Tailoring the spatial degree of freedom of light is an essential step towards the realization of advanced optical manipulation tools. A topical challenge consists of device miniaturization for ...improved performance and enhanced functionality at the micron scale. We demonstrate a novel approach that combines the additive three-dimensional (3D) structuring capability of laser polymerization and the subtractive subwavelength resolution patterning of focused ion beam lithography. As a case in point hybrid (dielectric/metallic) micro-optical elements that deliver a well-defined topological shaping of light are produced. Here we report on hybrid 3D binary spiral zone plates with unit and double topological charge. Their optical performances are compared to corresponding 2D counterparts both numerically and experimentally. Cooperative refractive capabilities without compromising topological beam shaping are shown. Realization of advanced designs where the dielectric architecture itself is endowed with singular properties is also discussed.
Two glycolytic enzymes, phosphoglycerate mutase (PGM) and enolase from Saccharomyces cerevisiae have been chosen to detect complex formation between active centers (a/c), using molecular dynamics ...simulation. Enzymes have been separated by 10 Å distance and placed in a water box of size 173 × 173 × 173 Å. Three different orientations where a/c of PGM and enolase were positioned toward each other have been used for investigation. The two initial 3-phosphoglycerate substrates at near active centers of initial structure of PGM have been replaced with final 2-phosphoglycerate products. 150mM of NaCl have been added to the system to observe binding activity in the near physiological conditions. Analysis of interaction energies and conformation changes for 3ns simulation indicates that PGM and enolase do show binding affinity between their near active regions. Moreover the similarity between final conformations of the first two orientations with the initial conformation of the third orientation suggests that complex formation between a/c of enzymes is not confined only by discussed orientations. Clear interaction of enolase with C-terminal tail of PGM has been recorded. These results suggest that substrate direct transfer mechanism may exist between enzymes.
Two glycolytic enzymes, phosphoglycerate mutase (PGM) and enolase from Saccharomyces cerevisiae, have been chosen to detect complex formation and possible channeling, using molecular dynamics ...simulation. The enzymes were separated by 10 angstroms distance and placed in a water-filled box of size 173 x 173 x 173 angstroms. Three different orientations have been investigated. The two initial 3-phosphoglycerate substrate molecules near the active centers of the initial structure of PGM have been replaced with final product (2-phosphoglycerate) molecules, and 150 mM NaCl together with three Mg2+ ions have been added to the system to observe post-catalytic activity under near-physiological conditions. Analysis of interaction energies and conformation changes for 3 nsec simulation indicates that PGM and enolase do show binding affinity between their near active regions, which is necessary for channeling to occur. Interaction of the C-terminal residues Ala239 and Val240 of PGM (which partially "cap" the 2-phosphoglycerate) with enolase also favors the existence of channeling.
The paper describes an application of the tree classification method Random Forest (RF), as used in the analysis of data from the ground-based gamma telescope MAGIC. In such telescopes, cosmic ...gamma-rays are observed and have to be discriminated against a dominating background of hadronic cosmic-ray particles. We describe the application of RF for this gamma/hadron separation. The RF method often shows superior performance in comparison with traditional semi-empirical techniques. Critical issues of the method and its implementation are discussed. An application of the RF method for estimation of a continuous parameter from related variables, rather than discrete classes, is also discussed.
Recently, the Galactic center has been reported to be a source of very high energy (VHE) g-rays by the CANGAROO, VERITAS, and HESS experiments. The energy spectra as measured by these experiments ...show substantial differences. In this Letter we present MAGIC observations of the Galactic center, resulting in the detection of a differential g-ray flux consistent with a steady, hard-slope power law, described as dN sub(g)/(dA dt dE) = (2.9 c 0.6) x 10 super(-12)(E/TeV) super(-2.2c0.2) cm super(-2) s super(-1) TeV super(-1). The g-ray source is centered at (R.A., decl.) = (17 super(h)45 super(m)20 super(s), -292'). This result confirms the previous measurements by the HESS experiment and indicates a steady source of TeV g-rays. We briefly describe the observational technique used and the procedure implemented for the data analysis, and we discuss the results in the perspective of different models proposed for the acceleration of the VHE g-rays.
Unfolding of differential energy spectra in the MAGIC experiment Albert, J.; Antoranz, P.; Armada, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2007, Volume:
583, Issue:
2
Journal Article
Peer reviewed
Open access
The paper describes the different methods, used in the MAGIC experiment, to unfold experimental energy distributions of cosmic ray particles (
γ
-rays). Questions and problems related to the ...unfolding are discussed. Various procedures are proposed which can help to make the unfolding robust and reliable. The different methods and procedures are implemented in the MAGIC software and are used in most of the analyses.
In 2005 and 2006, the MAGIC telescope observed very high energy gamma-ray emission from the distant BL Lac object PG 1553+113. The overall significance of the signal was 8.8 s for 18.8 hr of ...observation time. The light curve shows no significant flux variations on a daily timescale; the flux level during 2005 was, however, significantly higher compared to 2006. The differential energy spectrum between 690 and 500 GeV is well described by a power law with photon index = 4.2 c 0.3. The combined 2005 and 2006 energy spectrum provides an upper limit of z = 0.74 on the redshift of the object.
FADC signal reconstruction for the MAGIC telescope Albert, J.; Aliu, E.; Antoranz, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2008, Volume:
594, Issue:
3
Journal Article
Peer reviewed
Open access
Until April 2007 the Major Atmospheric Gamma ray Imaging Cherenkov (MAGIC) telescope used a 300
MSamples/s flash analog-to-digital converter (FADC) system to sample the shaped photomultiplier tube ...(PMT) signals produced by the captured Cherenkov photons of air showers. Different algorithms to reconstruct the signal from the read-out samples (extractors) have been implemented and are described and compared. Criteria based on the obtained charge and time resolution/bias are defined and used to judge the different extractors, by applying them to calibration, cosmic and pedestal signals. The achievable charge and time resolution have been derived as functions of the number of incident photo-electrons.
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