6,023 research outputs found
Novel schedule for treatment of inflammatory breast cancer
Inflammatory breast cancer (IBC) is the most aggressive form of this tumor, with the clinical and biological characteristics of a rapidly proliferating disease. This tumor is always diagnosed at advanced stages, atleast stage IIIB (locally advanced), so its management requires an integrated multidisciplinary approach with a systemic therapy followed by surgery and radiation therapy. Patients with IBC usually have a worse prognosis but the achievement of a pathologic complete response after neoadjuvant chemotherapy may have good rates of overall survival. We present the case of a 47 year old women with IBC, luminal B and with high proliferative index; she was successfully treated with a sequential schedule of chemotherapy (anthracyclines dose-dense/carboplatin+ taxane/Cyclophosphamide Methotrexate Fluorouracil), hormone-therapy, complementary radiotherapy and finally surgery until the achievement of a complete clinical and pathological response.
Luminal B inflammatory breast cancer with high proliferation index can benefit from sequential schedules of neoadjuvant chemotherapy and hormonal treatment and this can result in pathological complete response
Mitochondrial Function as a Determinant of Life Span
Average human life expectancy has progressively increased over many decades largely due to improvements in nutrition, vaccination, antimicrobial agents, and effective treatment/prevention of cardiovascular disease, cancer, etc. Maximal life span, in contrast, has changed very little. Caloric restriction (CR) increases maximal life span in many species, in concert with improvements in mitochondrial function. These effects have yet to be demonstrated in humans, and the duration and level of CR required to extend life span in animals is not realistic in humans. Physical activity (voluntary exercise) continues to hold much promise for increasing healthy life expectancy in humans, but remains to show any impact to increase maximal life span. However, longevity in Caenorhabditis elegans is related to activity levels, possibly through maintenance of mitochondrial function throughout the life span. In humans, we reported a progressive decline in muscle mitochondrial DNA abundance and protein synthesis with age. Other investigators also noted age-related declines in muscle mitochondrial function, which are related to peak oxygen uptake. Long-term aerobic exercise largely prevented age-related declines in mitochondrial DNA abundance and function in humans and may increase spontaneous activity levels in mice. Notwithstanding, the impact of aerobic exercise and activity levels on maximal life span is uncertain. It is proposed that age-related declines in mitochondrial content and function not only affect physical function, but also play a major role in regulation of life span. Regular aerobic exercise and prevention of adiposity by healthy diet may increase healthy life expectancy and prolong life span through beneficial effects at the level of the mitochondrion
Searching for star-planet magnetic interaction in CoRoT observations
Close-in massive planets interact with their host stars through tidal and
magnetic mechanisms. In this paper, we review circumstantial evidence for
star-planet interaction as revealed by the photospheric magnetic activity in
some of the CoRoT planet-hosting stars, notably CoRoT-2, CoRoT-4, and CoRoT-6.
The phenomena are discussed in the general framework of activity-induced
features in stars accompanied by hot Jupiters. The theoretical mechanisms
proposed to explain the activity enhancements possibly related with hot Jupiter
are also briefly reviewed with an emphasis on the possible effects at
photospheric level. The unique advantages of CoRoT and Kepler observations to
test these models are pointed out.Comment: Invited review paper accepted by Astrophysics and Space Science, 13
pages, 5 figure
Signatures of Star-planet interactions
Planets interact with their host stars through gravity, radiation and
magnetic fields, and for those giant planets that orbit their stars within
10 stellar radii (0.1 AU for a sun-like star), star-planet
interactions (SPI) are observable with a wide variety of photometric,
spectroscopic and spectropolarimetric studies. At such close distances, the
planet orbits within the sub-alfv\'enic radius of the star in which the
transfer of energy and angular momentum between the two bodies is particularly
efficient. The magnetic interactions appear as enhanced stellar activity
modulated by the planet as it orbits the star rather than only by stellar
rotation. These SPI effects are informative for the study of the internal
dynamics and atmospheric evolution of exoplanets. The nature of magnetic SPI is
modeled to be strongly affected by both the stellar and planetary magnetic
fields, possibly influencing the magnetic activity of both, as well as
affecting the irradiation and even the migration of the planet and rotational
evolution of the star. As phase-resolved observational techniques are applied
to a large statistical sample of hot Jupiter systems, extensions to other
tightly orbiting stellar systems, such as smaller planets close to M dwarfs
become possible. In these systems, star-planet separations of tens of stellar
radii begin to coincide with the radiative habitable zone where planetary
magnetic fields are likely a necessary condition for surface habitability.Comment: Accepted for publication in the handbook of exoplanet
Testing the recovery of stellar rotation signals from Kepler light curves using a blind hare-and-hounds exercise
We present the results of a blind exercise to test the recoverability of
stellar rotation and differential rotation in Kepler light curves. The
simulated light curves lasted 1000 days and included activity cycles, Sun-like
butterfly patterns, differential rotation and spot evolution. The range of
rotation periods, activity levels and spot lifetime were chosen to be
representative of the Kepler data of solar like stars. Of the 1000 simulated
light curves, 770 were injected into actual quiescent Kepler light curves to
simulate Kepler noise. The test also included five 1000-day segments of the
Sun's total irradiance variations at different points in the Sun's activity
cycle.
Five teams took part in the blind exercise, plus two teams who participated
after the content of the light curves had been released. The methods used
included Lomb-Scargle periodograms and variants thereof, auto-correlation
function, and wavelet-based analyses, plus spot modelling to search for
differential rotation. The results show that the `overall' period is well
recovered for stars exhibiting low and moderate activity levels. Most teams
reported values within 10% of the true value in 70% of the cases. There was,
however, little correlation between the reported and simulated values of the
differential rotation shear, suggesting that differential rotation studies
based on full-disk light curves alone need to be treated with caution, at least
for solar-type stars.
The simulated light curves and associated parameters are available online for
the community to test their own methods.Comment: Accepted for publication in MNRAS. Accepted, 13 April 2015. Received,
26 March 2015; in original form, 9 November 201
Constraints on the Mode and Extent of Sedimentary Rock Alteration in Hyper-Arid and Hypo-Thermal Environments
Geologic evidence suggests that the surface of Mars has been dominated by cold, dry, and relatively stable environmental conditions over the past ~3.5 Ga. These conditions differ from those pre-sumed to be present prior to ~3.5 Ga, when observa-tions indicate that the martian surface was at least in-termittently able to support the prolonged flow of liq-uid water. Despite the more than 75% of martian his-tory dominated by cold, dry, and stable conditions, few investigations have studied weathering and alteration processes that may influence the martian surface dur-ing this time. Please see attachment
The GAPS Programme with HARPS-N at TNG. III: The retrograde orbit of HAT-P-18b
The measurement of the Rossiter-McLaughlin effect for transiting exoplanets
places constraints on the orientation of the orbital axis with respect to the
stellar spin axis, which can shed light on the mechanisms shaping the orbital
configuration of planetary systems. Here we present the interesting case of the
Saturn-mass planet HAT-P-18b, which orbits one of the coolest stars for which
the Rossiter-McLaughlin effect has been measured so far. We acquired a
spectroscopic time-series, spanning a full transit, with the HARPS-N
spectrograph mounted at the TNG telescope. The very precise radial velocity
measurements delivered by the HARPS-N pipeline were used to measure the
Rossiter-McLaughlin effect. Complementary new photometric observations of
another full transit were also analysed to obtain an independent determination
of the star and planet parameters. We find that HAT-P-18b lies on a
counter-rotating orbit, the sky-projected angle between the stellar spin axis
and the planet orbital axis being lambda=132 +/- 15 deg. By joint modelling of
the radial velocity and photometric data we obtain new determinations of the
star (M_star = 0.770 +/- 0.027 M_Sun; R_star= 0.717 +/- 0.026 R_Sun;
Vsin(I_star) = 1.58 +/- 0.18 km/s) and planet (M_pl = 0.196 +/- 0.008 M_J; R_pl
= 0.947 +/- 0.044 R_J) parameters. Our spectra provide for the host star an
effective temperature T_eff = 4870 +/- 50 K, a surface gravity of log(g_star) =
4.57 +/- 0.07 cm/s, and an iron abundance of [Fe/H] = 0.10 +/- 0.06. HAT-P-18b
is one of the few planets known to transit a star with T_eff < 6250 K on a
retrograde orbit. Objects such as HAT-P-18b (low planet mass and/or relatively
long orbital period) most likely have a weak tidal coupling with their parent
stars, therefore their orbits preserve any original misalignment. As such, they
are ideal targets to study the causes of orbital evolution in cool
main-sequence stars.Comment: 5 pages, 2 figure
The HADES RV Programme with HARPS-N@TNG IV. Time resolved analysis of the Ca ii H&K and H{\alpha} chromospheric emission of low-activity early-type M dwarfs
M dwarfs are prime targets for planet search programs, particularly of those
focused on the detection and characterization of rocky planets in the habitable
zone. Understanding their magnetic activity is important because it affects our
ability to detect small planets, and it plays a key role in the
characterization of the stellar environment. We analyze observations of the Ca
II H&K and H{\alpha} lines as diagnostics of chromospheric activity for
low-activity early-type M dwarfs. We analyze the time series of spectra of 71
early-type M dwarfs collected for the HADES project for planet search purposes.
The HARPS-N spectra provide simultaneously the H&K doublet and the H{\alpha}
line. We develop a reduction scheme able to correct the HARPS-N spectra for
instrumental and atmospheric effects, and to provide flux-calibrated spectra in
units of flux at the stellar surface. The H&K and H{\alpha} fluxes are compared
with each other, and their variability is analyzed. We find that the H and K
flux excesses are strongly correlated with each other, while the H{\alpha} flux
excess is generally less correlated with the H&K doublet. We also find that
H{\alpha} emission does not increase monotonically with the H&K line flux,
showing some absorption before being filled in by chromospheric emission when
H&K activity increases. Analyzing the time variability of the emission fluxes,
we derive a tentative estimate of the rotation period (of the order of a few
tens of days) for some of the program stars, and the typical lifetime of
chromospheric active regions (a few stellar rotations). Our results are in good
agreement with previous studies. In particular, we find evidence that the
chromospheres of early-type M dwarfs could be characterized by different
filaments coverage, affecting the formation mechanism of the H{\alpha} line. We
also show that chromospheric structure is likely related to spectral type
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