188 research outputs found
JP3D compression of solar data-cubes: photospheric imaging and spectropolarimetry
Hyperspectral imaging is an ubiquitous technique in solar physics
observations and the recent advances in solar instrumentation enabled us to
acquire and record data at an unprecedented rate. The huge amount of data which
will be archived in the upcoming solar observatories press us to compress the
data in order to reduce the storage space and transfer times. The correlation
present over all dimensions, spatial, temporal and spectral, of solar data-sets
suggests the use of a 3D base wavelet decomposition, to achieve higher
compression rates. In this work, we evaluate the performance of the recent
JPEG2000 Part 10 standard, known as JP3D, for the lossless compression of
several types of solar data-cubes. We explore the differences in: a) The
compressibility of broad-band or narrow-band time-sequence; I or V stokes
profiles in spectropolarimetric data-sets; b) Compressing data in
[x,y,] packages at different times or data in [x,y,t] packages of
different wavelength; c) Compressing a single large data-cube or several
smaller data-cubes; d) Compressing data which is under-sampled or super-sampled
with respect to the diffraction cut-off
Primordial fluctuations from quantum gravity: 16-cell topological model
We present a numerical analysis of an Hartle-Hawking state for the early
universe, in the deep quantum regime, computed using the covariant Loop Quantum
Gravity formalism, in a truncation defined by 16-cell and in a simplified case
where the dynamics is defined by SU(2) BF theory. We compute mean geometry,
fluctuations and correlations. The results are consistent with the hypothesis
that refining the triangulation does not affect the global physical picture
substantially.Comment: 17 page
A Probabilistic Approach to the Drag-Based Model
The forecast of the time of arrival of a coronal mass ejection (CME) to Earth
is of critical importance for our high-technology society and for any future
manned exploration of the Solar System. As critical as the forecast accuracy is
the knowledge of its precision, i.e. the error associated to the estimate. We
propose a statistical approach for the computation of the time of arrival using
the drag-based model by introducing the probability distributions, rather than
exact values, as input parameters, thus allowing the evaluation of the
uncertainty on the forecast. We test this approach using a set of CMEs whose
transit times are known, and obtain extremely promising results: the average
value of the absolute differences between measure and forecast is 9.1h, and
half of these residuals are within the estimated errors. These results suggest
that this approach deserves further investigation. We are working to realize a
real-time implementation which ingests the outputs of automated CME tracking
algorithms as inputs to create a database of events useful for a further
validation of the approach.Comment: 18 pages, 4 figure
Sterile neutrinos: the necessity for a 5 sigma definitive clarification
Several different experiments have hinted to the existence of "anomalies" in
the neutrino sector, implying the possible presence of additional sterile
neutrinos or of other options. A definitive experimental search, capable to
clarify either in favour or against all these anomalies at the appropriate > 5
sigma level has been proposed by the ICARUS-NESSIE Collaboration. The technique
is based on two innovative concepts, namely (1) a large mass Liquid Argon Time
Projection Chamber (LAr-TPC) now in full operation at LNGS and (2) the search
for spectral differences in two identical detectors at different distances
along the (anti-)neutrino line(s).Comment: 7 pages, 4 figures, 1 tabl
TRANSLATE -- A Monte Carlo Simulation of Electron Transport in Liquid Argon
The microphysics of electron and photon propagation in liquid argon is a key
component of detector design and calibrations needed to construct and perform
measurements within a wide range of particle physics experiments. As
experiments grow in scale and complexity, and as the precision of their
intended measurements increases, the development of tools to investigate
important microphysics effects impacting such detectors becomes necessary. In
this paper we present a new time-domain Monte Carlo simulation of electron
transport in liquid argon. The simulation models the TRANSport in Liquid Argon
of near-Thermal Electrons (TRANSLATE) with the aim of providing a multi-purpose
software package for the study and optimization of detector environments, with
a particular focus on ongoing and next generation liquid argon neutrino
experiments utilizing the time projection chamber technology. TRANSLATE builds
on previous work of Wojcik and Tachiya, amongst others, introducing additional
cross-section processes up to ionization, thus modeling the full range of drift
electron scattering interactions. The simulation is validated by benchmarking
its performance with swarm parameters from data collected in experimental
setups operating in gas and liquid.Comment: 17 pages, 12 figure
Yersinia enterocolitica in Italy. A case of septicemia and abdominal aortic aneurysm infection
We report a case of Yersinia enterocolitica septicemia in a 63-year-old patient admitted to the Vascular Surgery Department of Umberto I Hospital (Rome, Italy) for an abdominal aortic aneurysm. The microorganism, recovered from both peripheral blood cultures and aneurysmatic aortic wall specimens, was identified as Y. enterocolitica using matrix-assisted laser desorption ionization-time of flight analysis (MALDI-TOF MS) and 16S rDNA gene sequencing. The isolate responsible for septicemia belonged to the O:9 serotype (biogroup 2). A genetic screening of the isolate made it possible to detect the presence of both the yst and ail genes, encoding a heat-stable enterotoxin and a protein involved in invasion/adherence and serum resistance, respectively. Our case contributes in enriching epidemiological data concerning Y. enterocolitica infections, which might represent severe complications in patients suffering from cardiovascular diseases. Moreover, this study, together with the others, should be regarded as valuable and useful tools for monitoring the rate of infections worldwide
Magnetic Resonance Cholangiopancreatography with Secretin Stimulation in the Diagnosis of Intraductal Papillary Mucinous Neoplasm: A Paradigmatic Case Report
Context. One of the characteristic findings of intraductal papillary mucinous neoplasms (IPMN) is the presence of a direct communication between the lesion and the ductal pancreatic system and when magnetic resonance cholangiopancreatography (MRCP) shows uncertain findings, it is useful to perform a MRCP after secretin stimulation (MRCP-S) which provides a better visualization of the ductal system. Case Report. We present a case of 51-year-old man in whom, during a CT follow-up for a renal tumour, was found a cystic lesion of the pancreas. To better evaluate the lesion and its suspected communication with the pancreatic system, MR with gadolinium and MRCP and MRCP-S were performed. With the MRCP and MRI it was not possible to identify a clear communication between the cystic lesion and the ductal system. MRCP-S showed an increase in signal intensity of the lesion and its communication with the ductal system, allowing us to classify the cystic lesion as a main duct in intraductal papillary mucinous neoplasm. The patient underwent a surgical duodenal pancreatectomy. The histological result of the specimen confirmed the diagnosis of adenocarcinoma IPMN. Conclusion. In this case MRCP-S has allowed a clearer identification of the cystic lesion allowing a correct diagnosis and treatment
Tissueâresonance interaction method for the noninvasive diagnosis of prostate cancer: analysis of a multicentre clinical evaluation
OBJECTIVETo determine, in a multicentre prospective study, the accuracy of the tissueâresonance interaction method (TRIMprob, new technology developed for the noninvasive analysis of electromagnetic anisotropy in biological tissues) in the diagnosis of prostate cancer.PATIENTS AND METHODSTwo hundred patients (mean age 67.4âyears) scheduled to have prostatic biopsies (because of a prostateâspecific, PSA, antigen level of â„4âng/mL or a suspicious digital rectal examination, DRE) were preliminarily examined while unaware of their clinical details using TRIMprob in five different centres. The final diagnosis obtained with TRIMprob was compared with the final histological diagnosis after extended biopsies.RESULTSOf the 188 evaluable patients (mean PSA levelâ9.3âng/mL, sd 8.8; mean prostate volume 62.0âmL, sd 32.4), 61 (32.4%) had a positive biopsy for adenocarcinoma of the prostate. The overall sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy of TRIMprob were 80%, 51%, 44%, 84% and 60%, respectively. The prostate cancer detection rate after biopsy was significantly higher in patients with a positive examination (49/111, 44%) than in patients with a negative TRIMprob (12/77, 15%; Pâ<â0.001). When TRIMprob results were combined with DRE findings the sensitivity and NPV both increased to 92%.CONCLUSIONTRIMprob seems to be a useful tool in the diagnosis of prostate cancer and can increase the accuracy of PSA or DRE results. The high NPV suggests that this new technology might be useful to reduce the indications for prostatic biopsy or repeated series of biopsies in patients suspected of having prostate cancer
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