188 research outputs found

    JP3D compression of solar data-cubes: photospheric imaging and spectropolarimetry

    Full text link
    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,λ\lambda] 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

    Full text link
    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

    Full text link
    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

    Full text link
    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

    Full text link
    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

    Get PDF
    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

    Get PDF
    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

    Tissue‐resonance interaction method for the noninvasive diagnosis of prostate cancer: analysis of a multicentre clinical evaluation

    Get PDF
    OBJECTIVETo determine, in a multicentre prospective study, the accuracy of the tissue‐resonance 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 67.4 years) scheduled to have prostatic biopsies (because of a prostate‐specific, PSA, antigen level of ≄4 ng/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 level 9.3 ng/mL, sd 8.8; mean prostate volume 62.0 mL, 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%; P < 0.001). 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
    • 

    corecore