3,575 research outputs found
A novel CMB polarization likelihood package for large angular scales built from combined WMAP and Planck LFI legacy maps
We present a CMB large-scale polarization dataset obtained by combining WMAP
Ka, Q and V with Planck 70 GHz maps. We employ the legacy frequency maps
released by the WMAP and Planck collaborations and perform our own Galactic
foreground mitigation technique, which relies on Planck 353 GHz for polarized
dust and on Planck 30 GHz and WMAP K for polarized synchrotron. We derive a
single, optimally-noise-weighted, low-residual-foreground map and the
accompanying noise covariance matrix. These are shown, through
analysis, to be robust over an ample collection of Galactic masks. We use this
dataset, along with the Planck legacy Commander temperature solution, to build
a pixel-based low-resolution CMB likelihood package, whose robustness we test
extensively with the aid of simulations, finding excellent consistency. Using
this likelihood package alone, we constrain the optical depth to reionazation
at C.L., on 54\% of the sky. Adding the
Planck high- temperature and polarization legacy likelihood, the Planck
lensing likelihood and BAO observations we find
in a full CDM exploration. The
latter bounds are slightly less constraining than those obtained employing
\Planck\ HFI CMB data for large angle polarization, that only include EE
correlations. Our bounds are based on a largely independent dataset that does
include also TE correlations. They are generally well compatible with Planck
HFI preferring slightly higher values of . We make the low-resolution
Planck and WMAP joint dataset publicly available along with the accompanying
likelihood code.Comment: The WMAP+LFI likelihood module is available on
\http://www.fe.infn.it/u/pagano/low_ell_datasets/wmap_lfi_legacy
Oil Spills and Slicks imaged by Synthetic Aperture Radar
Oil spills and slicks occur in the ocean around the world due to natural seeps, oil extraction, transportation, and consumption. Satellite synthetic aperture radar (SAR) has proven to be an efficient tool for identifying and classifying oil on the sea surface. This information can be used to monitor
areas for potential illegal marine discharge or to respond to an oil spill incident. When used to monitor shipping lanes or drilling platforms, timely analysis can identify offending parties and lead to prosecution. Following an oil spill such as that from the Deepwater Horizon rig in the Gulf of Mexico in 2010, SAR can be used to direct response activities and optimize available resources
La stima del campo di gravità da dati GOCE: i risultati finali dell’approccio space-wise
In questo lavoro vengono presentati i risultati finali del processamento dati della missione GOCE tramite l’approccio space-wise, da oltre vent’anni studiato ed implementato presso il Politecnico di Milano. In particolare sono stati elaborati i dati di tutta la missione, da novembre 2009 ad ottobre 2013, corrispondente ad oltre cento milioni di epoche. Questo periodo include sia la fase iniziale, durata quasi 3 anni, con il satellite all’altezza nominale di 255 km, sia la fase finale di abbassamento dell’orbita nella quale il satellite è stato lentamente portato fino a 224 km passando attraverso periodi intermedi di misura a quota costante. La fase di preprocessamento dati per la ricerca e la correzione di outlier è stata svolta in modo semi-automatico con una supervisione continua da parte dell’operatore e per questo motivo è stata molto onerosa; tuttavia l’eliminazione degli outlier, presenti in maggior numero nell’ultima fase di abbassamento dell’orbita, è cruciale per il raggiungimento di un risultato soddisfacente, indipendentemente dal metodo di analisi successivamente utilizzato. L’approccio space-wise è sostanzialmente un approccio iterativo di collocazione, che richiede la modellizzazione sia della correlazione temporale dell’errore di misura del gradiometro a bordo del satellite, sia della correlazione spaziale del segnale di gravità che si vuole recuperare. In particolare, l’idea base di questo approccio è quella di ridurre l’enorme mole di dati lungo orbita su una griglia globale all’altezza del satellite applicando la collocazione su aree locali, ciascuna caratterizzata da una covarianza del segnale adattata localmente. In questo modo il livello del filtraggio del dato risulta controllato localmente, diversamente da quanto avviene negli approcci diretto e time-wise dove viene applicata una regolarizzazione globale alla stima ai minimi quadrati dei coefficienti delle armoniche sferiche. Il risultato di questo processamento consiste quindi in griglie globali di derivate seconde del potenziale gravitazionale a una risoluzione spaziale di 0.2°x0.2°. Da queste griglie si deriva un modello globale in armoniche sferiche attraverso integrazione numerica. Sia per le griglie che per i coefficienti armonici viene fornita una stima dell’errore calcolata tramite un’opportuna simulazione Monte Carlo. Il contenuto informativo dei prodotti space-wise è stato valutato confrontandoli con altre griglie e altri modelli globali disponibili. Questo confronto mette in rilievo l’ovvia debolezza della collocazione locale nella stima dei gradi medio-bassi del campo gravitazionale, ma anche la sua miglior capacità di recuperare i più alti degree, ovvero i dettagli del campo. In questo senso l’approccio space-wise può fornire un risultato complementare a quello degli altri due approcci ufficiali all’analisi dati GOCE
Tadalafil modulates aromatase activity and androgen receptor expression in a human osteoblastic cell in vitro model
Purpose Phosphodiesterase type-5 inhibitor (PDE5i)
tadalafil administration in men with erectile dysfunction is
associated with increased testosterone/estradiol ratio, leading
to hypothesize a potential increased effect of androgen
action on target tissues. We aimed to characterize, in a cellular
model system in vitro, the potential modulation of
aromatase and sex steroid hormone receptors upon exposure
to tadalafil (TAD).
Methods Human osteoblast-like cells SAOS-2 were chosen
as an in vitro model system since osteoblasts are target
of steroid hormones. Cells were tested for viability upon
TAD exposure, which increased cell proliferation. Then,
cells were treated with/without TAD for several times to
evaluate potential modulation in PDE5, aromatase (ARO),
androgen (AR) and estrogen (ER) receptor expression.
Results Osteoblasts express significant levels of both PDE5
mRNA and protein. Exposure of cells to increasing concentrations
of TAD (10−8–10−7 M) decreased PDE5 mRNA and
protein expression. Also, TAD inhibited ARO mRNA and
protein expression leading to an increase in testosterone levels
in the supernatants. Interestingly, TAD increased total AR mRNA and protein expression and decreased ERα, with an
increased ratio of AR/ER, suggesting preferential androgenic
vs estrogenic pathway activation.
Conclusions Our results demonstrate for the first time
that TAD decreases ARO expression and increases AR
protein expression in human SAOS-2, strongly suggesting
a new control of steroid hormones pathway by PDE5i.
These findings might represent the first evidence of translational
actions of PDE5i on AR, which leads to hypothesize
a growing relevance of this molecule in men with
prostate cancer long-term treated with TAD for sexual
rehabilitation.
Keywords Tadalafil · Osteoblasts · Aromatase · Androgen
receptor · Estrogen recepto
Retrieval of phenological stages of onion fields during the first year of growth by means of C-band polarimetric SAR measurements
The phenological stages of onion fields in the first year of growth are estimated using polarimetric observables and single-polarization intensity channels. Experiments are undertaken on a time series of RADARSAT-2 C-band full-polarimetric synthetic aperture radar (SAR) images collected in 2009 over the Barrax region, Spain, where ground truth information about onion growth stages is provided by the European Space Agency (ESA)-funded agricultural bio/geophysical retrieval from frequent repeat pass SAR and optical imaging (AgriSAR) field campaign conducted in that area. The experimental results demonstrate that polarimetric entropy or copolar coherence when used jointly with the cross-polarized intensity allows unambiguously distinguishing three phenological intervals.This work was partially supported by the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER, under Project TEC2011-28201-C02-02
Study of second lightest neutralino spin measurement with ATLAS detector at LHC
One of the goals of the ATLAS experiment at the CERN Large Hadron Collider is to search for evidence of Supersymmetry (SUSY) signals. If SUSY would be discovered, it will be fundamental to measure the spin of the new particles in order to prove that they are indeed supersymmetric partners. Left-handed squark cascade decay to second lightest neutralino which further decays to slepton can represent a good opportunity for SUSY particles' spin measurement. Assuming the neutralino spin to be 1/2, the invariant mass distributions of some detectable final products of the reactions have to be charge asymmetric. In the present work the detectability of this charge asymmetry is analysed in the stau-coannihilation region and in the bulk region of the minimal Supergravity parameter space allowed by the latest experimental constraints. The criteria used to isolate the decay chain of interest and to reject the background, coming from both Standard Model and different SUSY decay channels, are described as obtained by suitable optimizations on Monte Carlo samples produced with the ATLAS fast simulation. The estimates of the residual contributions to background and of the applied cut efficiencies are presented. Results on charge asymmetry are then shown and discussed
Neutralino spin measurement with ATLAS detector at LHC
Minimal Supergravity (mSUGRA) [1] Supersimmetry breaking mechanism is a leading candidate for yielding new physics beyond the Standard Model (SM). Within mSUGRA framework masses, mixings and decays of all SUSY and Higgs particles are determined in terms of four input parameters and a sign: the common mass m 0 of scalar particles at the grand unification scale, the common fermion mass m 1/2, the common trilinear coupling A 0, the ratio of the Higgs vacuum expectation values tan β and the sign of the supersymmetric Higgs mass parameter μ. Once a signal of a physics beyond the Standard Model is seen at LHC, it will be fundamental to measure properties of new particles, like spin, in order to prove that they are indeed supersymmetric partners. The present work [2] is based on the spin analysis method proposed in [3] and allows the discrimination of different hypotheses for spin assignments. Some studies [4, 5] show that this method can also be used for the discrimination of SUSY from an Universal Extra Dimensions model which can mimick low energy SUSY at hadron colliders. In this report two selected points inside stau-coannihilation and bulk regions of the allowed mSUGRA parameter space are considered. Fast simulation [6] of the ATLAS detector was performed in order to investigate the feasibility of supersymmetric particles’ spin measurement
Posterior cortical atrophy and Alzheimer’s disease : a meta-analytic review of neuropsychological and brain morphometry studies
This paper presents the first systematic review and meta-analysis of neuropsychological and brain morphometry studies comparing posterior cortical atrophy (PCA) to typical Alzheimer's disease (tAD). Literature searches were conducted for brain morphometry and neuropsychological studies including a PCA and a tAD group. Compared to healthy controls (HC), PCA patients exhibited significant decreases in temporal, occipital and parietal gray matter (GM) volumes, whereas tAD patients showed extensive left temporal atrophy. Compared to tAD patients, participants with PCA showed greater GM volume reduction in the right occipital gyrus extending to the posterior lobule. In addition, PCA patients showed less GM volume loss in the left parahippocampal gyrus and left hippocampus than tAD patients. PCA patients exhibit significantly greater impairment in Immediate Visuospatial Memory as well as Visuoperceptual and Visuospatial Abilities than patients with tAD. However, tAD patients showed greater impairment in Delayed Auditory/Verbal Memory than patients with PCA. PCA is characterized by significant atrophy of the occipital and parietal regions and severe impairments in visuospatial functioning.JA is funded by a doctoral grant from the Foundation for Science and Technology, FCT (SFRH/BD/64457/2009, co-funded by FSE/POPH). JA and AS are funded by project PIC/IC/83290/2007, which is supported by FEDER (POFC-COMPETE) and FCT. JMS is supported by a fellowship of the project SwitchBox-FP7-HEALTH-2010-grant 259772-2. These organizations had no role in the study design, data collection, analysis, interpretation, or in the decision to submit the paper for publication
Planck intermediate results. XXIX. All-sky dust modelling with Planck, IRAS, and WISE observations
We present all-sky modelling of the high resolution Planck, IRAS, and WISE
infrared (IR) observations using the physical dust model presented by Draine
and Li in 2007 (DL). We study the performance and results of this model, and
discuss implications for future dust modelling. The present work extends the DL
dust modelling carried out on nearby galaxies using Herschel and Spitzer data
to Galactic dust emission. We employ the DL dust model to generate maps of the
dust mass surface density, the optical extinction Av, and the starlight
intensity parametrized by Umin. The DL model reproduces the observed spectral
energy distribution (SED) satisfactorily over most of the sky, with small
deviations in the inner Galactic disk and in low ecliptic latitude areas. We
compare the DL optical extinction Av for the diffuse interstellar medium with
optical estimates for 2 10^5 quasi-stellar objects (QSOs) observed in the Sloan
digital sky survey. The DL Av estimates are larger than those determined
towards QSOs by a factor of about 2, which depends on Umin. The DL fitting
parameter Umin, effectively determined by the wavelength where the SED peaks,
appears to trace variations in the far-IR opacity of the dust grains per unit
Av, and not only in the starlight intensity. To circumvent the model
deficiency, we propose an empirical renormalization of the DL Av estimate,
dependent of Umin, which compensates for the systematic differences found with
QSO observations. This renormalization also brings into agreement the DL Av
estimates with those derived for molecular clouds from the near-IR colours of
stars in the 2 micron all sky survey. The DL model and the QSOs data are used
to compress the spectral information in the Planck and IRAS observations for
the diffuse ISM to a family of 20 SEDs normalized per Av, parameterized by
Umin, which may be used to test and empirically calibrate dust models.Comment: Final version that has appeared in A&
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