82 research outputs found
Robust Gravitational Wave Burst Detection and Source Localization in a Network of Interferometers Using Cross Wigner Spectra
We discuss a fast cross-Wigner transform based technique for detecting
gravitational wave bursts, and estimating the direction of arrival, using a
network of (three) non co-located interferometric detectors. The performances
of the detector as a function of signal strength and source location, and the
accuracy of the direction of arrival estimation are investigated by numerical
simulations.Comment: accepted in Class. Quantum Gravit
Iterative message-passing-based algorithms to detect spreading codes
This thesis tackles the issue of the rapid acquisition of spreading codes in Direct-Sequence Spread-Spectrum (DS/SS) communication systems. In particular, a new algorithm is proposed that exploits the experience of the iterative
decoding of modern codes (LDPC and turbo codes) to detect these sequences. This new method is a Message-Passing-based algorithm.
Specifically, instead of correlating the received signal with local replicas of the transmitted linear feedback shift register (LFSR) sequence, an iterative Message-Passing algorithm is implemented to be run on a loopy graph. In particular, these graphical models are designed by manipulating the generating polynomial structure of the considered LFSR sequence.
Therefore, this contribution is a detailed analysis of the detection technique based on Message-Passing algorithms to acquire m-Sequences and Gold codes. More in detail, a unified treatment to design and implement a specific set of graphical models for these codes is reported. A theoretical study on the acquisition time performance and their comparison to the standard algorithms (full-parallel, simple-serial, and hybrid searches) is done. A preliminary architectural design is also provided. Finally, the analysis is also enriched by comparing this new technique to the standard algorithms in terms of computational complexity and (missed/wrong/correct) acquisition probabilities as derived by simulations
Software-Defined Radio Technologies forGNSS Receivers: A Tutorial Approach to a SimpleDesign and Implementation
The field of satellite navigation has witnessed the
advent of a number of new systems and technologies: after
the landmark design and development of the Global Positioning
System (GPS), a number of new independent Global Navigation
Satellite Systems (GNSSs) were or are being
developed all over the world: Russia's GLONASS, Europe's
GALILEO, and China's BEIDOU-2, to mention a few. In this ever-changing context, the availability of reliable and flexible receivers is becoming a priority for a host of
applications, including research, commercial, civil, and military.
Flexible means here both easily upgradeable for future needs
and/or on-the-fly reprogrammable to adapt to different signal
formats. An effective approach to meet these design goals is the
software-defined radio (SDR) paradigm. In the last few years, the
availability of new processors with high computational power
enabled the development of (fully) software receivers whose
performance is comparable to or better than that of conventional
hardware devices, while providing all the advantages of a flexible
and fully configurable architecture. The aim of this tutorial paper
is surveying the issue of the general architecture and design
rules of a GNSS software receiver, through a comprehensive
discussion of some techniques and algorithms, typically applied
in simple PC-based receiver implementations
The Araucaria Project. The Distance to the Small Magellanic Cloud from Near-Infrared Photometry of RR Lyrae Variables
We have obtained deep infrared J and K band observations of nine 4.9x4.9
arcmin fields in the Small Magellanic Cloud (SMC) with the ESO New Technology
Telescope equipped with the SOFI infrared camera. In these fields, 34 RR Lyrae
stars catalogued by the OGLE collaboration were identified. Using different
theoretical and empirical calibrations of the infrared
period-luminosity-metallicity relation, we find consistent SMC distance moduli,
and find a best true distance modulus to the SMC of 18.97 +/- 0.03
(statistical) +/- 0.12 (systematic) mag which agrees well with most independent
distance determinations to this galaxy, and puts the SMC 0.39 mag more distant
than the LMC for which our group has recently derived, from the same technique,
a distance of 18.58 mag.Comment: AJ submitted and accepte
In BCR-ABL1 Positive B-Cell Acute Lymphoblastic Leukemia, Steroid Therapy Induces Hypofibrinogenemia
Hypofibrinogenemia (HF) in adult acute lymphoblastic leukemia (ALL) of B lineage is
uncommon and mostly associated with asparaginase (ASP) delivery. Since we noticed a significant
reduction in fibrinogen (FBG) plasma levels even before the first ASP dose, we aim to assess the
levels of FBG during induction treatment and explore if the FBG fall correlated with therapies other
than asparaginase and/or specific leukemia biological features. We retrospectively analyzed FBG
levels in 115 patients with B-ALL. In 74 (64%) out of 115 patients FBG decline occurred during the
steroid prephase. In univariate analysis, such a steroid-related HF was significantly associated with
BCR-ABL1 rearrangement (p = 0.00158). None of those experiencing HF had significant modifications
of liver function tests during induction treatment. Our retrospective study suggests that in B-ALL,
steroid therapy can also induce HF and that such an event is preferentially observed in patients
carrying BCR-ABL1 rearrangements. The pathogenesis of this phenomenon is still unclear. We attempt
to explain it by applying the International Society of Thrombosis and Hemostasis-Disseminated
Intravascular Coagulation score (ISTH-DIC score); nonetheless additional studies are needed to
clarify further the mechanisms of HF in this subset of patients
Multicenter Observational Retrospective Study on Febrile Events in Patients with Acute Myeloid Leukemia Treated with Cpx-351 in "Real-Life": The SEIFEM Experience
: In the present study, we aimed to evaluate the absolute risk of infection in the real-life setting of AML patients treated with CPX-351. The study included all patients with AML from 30 Italian hematology centers of the SEIFEM group who received CPX-351 from July 2018 to June 2021. There were 200 patients included. Overall, 336 CPX-351 courses were counted: all 200 patients received the first induction cycle, 18 patients (5%) received a second CPX-351 induction, while 86 patients (26%) proceeded with the first CPX-351 consolidation cycle, and 32 patients (10%) received a second CPX-351 consolidation. A total of 249 febrile events were recorded: 193 during the first or second induction, and 56 after the first or second consolidation. After the diagnostic work-up, 92 events (37%) were classified as febrile neutropenia of unknown origin (FUO), 118 (47%) were classifiable as microbiologically documented infections, and 39 (17%) were classifiable as clinically documented infections. The overall 30-day mortality rate was 14% (28/200). The attributable mortality-infection rate was 6% (15/249). A lack of response to the CPX-351 treatment was the only factor significantly associated with mortality in the multivariate analysis [p-value: 0.004, OR 0.05, 95% CI 0.01-0.39]. Our study confirms the good safety profile of CPX-351 in a real-life setting, with an incidence of infectious complications comparable to that of the pivotal studies; despite prolonged neutropenia, the incidence of fungal infections was low, as was infection-related mortality
Covid-19 and the role of smoking: the protocol of the multicentric prospective study COSMO-IT (COvid19 and SMOking in ITaly).
The emergency caused by Covid-19 pandemic raised interest in studying lifestyles and comorbidities as important determinants of poor Covid-19 prognosis. Data on tobacco smoking, alcohol consumption and obesity are still limited, while no data are available on the role of e-cigarettes and heated tobacco products (HTP). To clarify the role of tobacco smoking and other lifestyle habits on COVID-19 severity and progression, we designed a longitudinal observational study titled COvid19 and SMOking in ITaly (COSMO-IT). About 30 Italian hospitals in North, Centre and South of Italy joined the study. Its main aims are: 1) to quantify the role of tobacco smoking and smoking cessation on the severity and progression of COVID-19 in hospitalized patients; 2) to compare smoking prevalence and severity of the disease in relation to smoking in hospitalized COVID-19 patients versus patients treated at home; 3) to quantify the association between other lifestyle factors, such as e-cigarette and HTP use, alcohol and obesity and the risk of unfavourable COVID-19 outcomes. Socio-demographic, lifestyle and medical history information will be gathered for around 3000 hospitalized and 700-1000 home-isolated, laboratory-confirmed, COVID-19 patients. Given the current absence of a vaccine against SARS-COV-2 and the lack of a specific treatment for -COVID-19, prevention strategies are of extreme importance. This project, designed to highly contribute to the international scientific debate on the role of avoidable lifestyle habits on COVID-19 severity, will provide valuable epidemiological data in order to support important recommendations to prevent COVID-19 incidence, progression and mortality
The Third Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
We present 294 pulsars found in GeV data from the Large Area Telescope (LAT)
on the Fermi Gamma-ray Space Telescope. Another 33 millisecond pulsars (MSPs)
discovered in deep radio searches of LAT sources will likely reveal pulsations
once phase-connected rotation ephemerides are achieved. A further dozen optical
and/or X-ray binary systems co-located with LAT sources also likely harbor
gamma-ray MSPs. This catalog thus reports roughly 340 gamma-ray pulsars and
candidates, 10% of all known pulsars, compared to known before Fermi.
Half of the gamma-ray pulsars are young. Of these, the half that are undetected
in radio have a broader Galactic latitude distribution than the young
radio-loud pulsars. The others are MSPs, with 6 undetected in radio. Overall,
>235 are bright enough above 50 MeV to fit the pulse profile, the energy
spectrum, or both. For the common two-peaked profiles, the gamma-ray peak
closest to the magnetic pole crossing generally has a softer spectrum. The
spectral energy distributions tend to narrow as the spindown power
decreases to its observed minimum near erg s, approaching the
shape for synchrotron radiation from monoenergetic electrons. We calculate
gamma-ray luminosities when distances are available. Our all-sky gamma-ray
sensitivity map is useful for population syntheses. The electronic catalog
version provides gamma-ray pulsar ephemerides, properties and fit results to
guide and be compared with modeling results.Comment: 142 pages. Accepted by the Astrophysical Journal Supplemen
Buffered high charge spectrally-peaked proton beams in the relativistic-transparency regime
Spectrally-peaked proton beams of high charge (Ep » 8 MeV, DE » 4 MeV, N » 50 nC ) have been observed from the interaction of an intense laser (>1019 W cm−2) with ultrathin CH foils, as measured by spectrally-resolved full beam profiles. These beams are reproducibly generated for foil thicknesses 5–100 nm, and exhibit narrowing divergence with decreasing target thickness down to »8 for 5 nm. Simulations demonstrate that the narrow energy spread feature is a result of buffered acceleration of protons. The radiation pressure at the front of the target results in asymmetric sheath fields which permeate throughout the target, causing preferential forward acceleration. Due to their higher charge- to-mass ratio, the protons outrun a carbon plasma driven in the relativistic transparency regime
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