454 research outputs found

    Compressive Hyperspectral Imaging Using Progressive Total Variation

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    Compressed Sensing (CS) is suitable for remote acquisition of hyperspectral images for earth observation, since it could exploit the strong spatial and spectral correlations, llowing to simplify the architecture of the onboard sensors. Solutions proposed so far tend to decouple spatial and spectral dimensions to reduce the complexity of the reconstruction, not taking into account that onboard sensors progressively acquire spectral rows rather than acquiring spectral channels. For this reason, we propose a novel progressive CS architecture based on separate sensing of spectral rows and joint reconstruction employing Total Variation. Experimental results run on raw AVIRIS and AIRS images confirm the validity of the proposed system.Comment: To be published on ICASSP 2014 proceeding

    Antitumor Trans Platinum DNA Adducts: NMR and HPLC Study of the Interaction Between a trans-Pt Iminoether Complex and the Deoxy Decamer d(CCTCGCTCTC)·d(GAGAGCGAGG)

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    The single-stranded oligonucleotide 5â€Č-d(CCTCGCTCTC) (I) was reacted with the antitumor trans platinum iminoderivative trans-[PtCl2{E-HN = C(OMe)Me}2] (trans-EE) and subsequently annealed with its complementary strand 5â€Č-d(GAGAGCGAGG) (II). The platinated duplex was characterized by 1D and 2D proton NMR spectroscopy at 600 MHz. In agreement with previous studies by different techniques trans-EE was found to form a monofunctional adduct with the duplex involving the guanine residue. The modification by trans-EE has been found to induce only minor local distortion in the duplex geometry. Two key crosspeaks observed in the NOESY map corresponding to a close contact between G5-H8 and the methoxy and the methyl group, respectively, enabled us to dock the trans-EE complex with the duplex by geometry optimization. The results support the idea that the antitumor activity of trans-EE is related to lesion of DNA fundamentally different from that of cisplatin. Unexpectedly, the NOESY spectra indicated that at the high NaCl concentration used (0.2 M) the duplex was found to undergo slow deplatination. This was subsequently proved by HPLC. In a separate experiment on platination of the single strand in a salt free environment the HPLC analysis showed that the monofunctional adduct was not deplatinated, however, after 24 hours, additidnal minor isomers were detected

    Effect of mofezolac-galactose distance in conjugates targeting cyclooxygenase (COX)-1 and CNS GLUT-1 carrier

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    Neuroinflammation is the earliest stage of several neurological and neurodegenerative diseases. In the case of neurodegenerative disorders, it takes place about 15Ăą 20 years before the appearance of specific neurodegenerative clinical symptoms. Constitutive microglial COX-1 is one of the pro-inflammatory players of the neuroinflammation. Novel compounds 3, 14 and 15 (Galmof0, Galmof5and Galmof11, respectively) were projected, and their synthetic methodologies developed, by linking by an ester bond, directly or through a C5 or C11 unit linker the highly selective COX-1 inhibitor mofezolac (COXs selectivity index > 6000) to galactose in order to obtain substances capable to cross blood-brain barrier (BBB) and control the CNS inflammatory response. 3, 14 and 15 (Galmofs) were prepared in good to fair yields. Galmof0(3) was found to be a selective COX-1 inhibitor (COX-1 IC50= 0.27 ĂŽÂŒM and COX-2 IC50= 3.1 ĂŽÂŒM, selectivity index = 11.5), chemically and metabolically stable, and capable to cross Caco-2 cell monolayer, resembling BBB, probing that its transport is GLUT-1-mediated. Furthermore, Galmof0(3) powerfully inhibits PGE2release higher than mofezolac (1) in LPS-stimulated mouse BV2 microglial cell line, a worldwide recognized neuroinflammation model. In addition, Fingerprints for Ligands and Proteins (FLAP) was used to explain the different binding interactions of Galmofs with the COX-1 active site

    Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory

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    We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 80∘80^\circ and energies in excess of 4 EeV (4×10184 \times 10^{18} eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional information on any observed anisotropies. No deviation from isotropy is observed on any angular scale in the energy range between 4 and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no other deviation from isotropy is observed for moments beyond the dipole one. The corresponding pp-values obtained after accounting for searches blindly performed at several angular scales, are 1.3×10−51.3 \times 10^{-5} in the case of the angular power spectrum, and 2.5×10−32.5 \times 10^{-3} in the case of the needlet analysis. While these results are consistent with previous reports making use of the same data set, they provide extensions of the previous works through the thorough scans of the angular scales.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Calibration of the Logarithmic-Periodic Dipole Antenna (LPDA) Radio Stations at the Pierre Auger Observatory using an Octocopter

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    An in-situ calibration of a logarithmic periodic dipole antenna with a frequency coverage of 30 MHz to 80 MHz is performed. Such antennas are part of a radio station system used for detection of cosmic ray induced air showers at the Engineering Radio Array of the Pierre Auger Observatory, the so-called Auger Engineering Radio Array (AERA). The directional and frequency characteristics of the broadband antenna are investigated using a remotely piloted aircraft (RPA) carrying a small transmitting antenna. The antenna sensitivity is described by the vector effective length relating the measured voltage with the electric-field components perpendicular to the incoming signal direction. The horizontal and meridional components are determined with an overall uncertainty of 7.4^{+0.9}_{-0.3} % and 10.3^{+2.8}_{-1.7} % respectively. The measurement is used to correct a simulated response of the frequency and directional response of the antenna. In addition, the influence of the ground conductivity and permittivity on the antenna response is simulated. Both have a negligible influence given the ground conditions measured at the detector site. The overall uncertainties of the vector effective length components result in an uncertainty of 8.8^{+2.1}_{-1.3} % in the square root of the energy fluence for incoming signal directions with zenith angles smaller than 60{\deg}.Comment: Published version. Updated online abstract only. Manuscript is unchanged with respect to v2. 39 pages, 15 figures, 2 table

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 60∘60^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law E−γE^{-\gamma} with index Îł=2.70±0.02 (stat)±0.1 (sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25 (stat)−1.2+1.0 (sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Ultrahigh-energy neutrino follow-up of Gravitational Wave events GW150914 and GW151226 with the Pierre Auger Observatory

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    On September 14, 2015 the Advanced LIGO detectors observed their first gravitational-wave (GW) transient GW150914. This was followed by a second GW event observed on December 26, 2015. Both events were inferred to have arisen from the merger of black holes in binary systems. Such a system may emit neutrinos if there are magnetic fields and disk debris remaining from the formation of the two black holes. With the surface detector array of the Pierre Auger Observatory we can search for neutrinos with energy above 100 PeV from point-like sources across the sky with equatorial declination from about -65 deg. to +60 deg., and in particular from a fraction of the 90% confidence-level (CL) inferred positions in the sky of GW150914 and GW151226. A targeted search for highly-inclined extensive air showers, produced either by interactions of downward-going neutrinos of all flavors in the atmosphere or by the decays of tau leptons originating from tau-neutrino interactions in the Earth's crust (Earth-skimming neutrinos), yielded no candidates in the Auger data collected within ±500\pm 500 s around or 1 day after the coordinated universal time (UTC) of GW150914 and GW151226, as well as in the same search periods relative to the UTC time of the GW candidate event LVT151012. From the non-observation we constrain the amount of energy radiated in ultrahigh-energy neutrinos from such remarkable events.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
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