The MRPC-based ALICE Time-Of-Flight detector: status and performance

The large Time-Of-Flight (TOF) array is one of the main detectors devoted to charged hadron identification in the mid-rapidity region of the ALICE experiment at the LHC. It allows separation among pions, kaons and protons up to a few GeV/c, covering the full azimuthal angle and -0.9 < eta < 0.9. The TOF exploits the innovative MRPC technology capable of an intrinsic time resolution better than 50 ps with an efficiency close to 100% and a large operational plateau; the full array consists of 1593 MRPCs covering a cylindrical surface of 141 m2. The TOF detector has been efficiently taking data since the first pp collisions recorded in ALICE in December 2009. In this report, the status of the TOF detector and the performance achieved for both pp and Pb--Pb collisions are described.Comment: 4 pages, 6 figure

Photonic magnetic metamaterial basics

Cataloged from PDF version of article.In the present study, we provide a detailed analysis for the study of photonic metamaterials. We demonstrate the polarization and orientation dependent transmission response of split ring resonators at the infrared and visible band. We provided optical measurements only for one case, in which electric component of the incident field was coupled to planar split ring resonator array. We consecutively studied (i) frequency tuning, (ii) effect of resonator density, (iii) shifting magnetic resonance frequency by changing the resonator shape, and (iv) effect of metal loss and plasma frequency. The study provides an overlook for the candidate applications such as the enhancement of power passing through an electrically small hole, negative index metamaterials and optical metamaterial absorbers. (C) 2010 Elsevier B.V. All rights reserved

Maternal and neonatal effects of adding morphine to low‑dose bupivacaine for epidural labor analgesia

Aim: Labor is one of the most painful experiences a woman may face during her lifetime. One of the most effective methods used for eliminating this pain is epidural analgesia. The aim of this study to determine the impact of adding morphine to low‑dose bupivacaine epidural anesthesia on labor and neonatal outcomes, and maternal side effects.Materials and Methods: This is a prospective randomized double‑blind study comparing two regimens of anesthetic agents used for epidural anesthesia in labor. A total of 120 pregnant women were randomized into two groups with 60 subjects in each study arm. A catheter was inserted, and 0.1% bupivacaine + 2 μg/mL fentanyl in 15 mL saline were given to Group bupivacaine‑fentanyl (Group BF), while 0.0625% bupivacaine + 2 μg/ml fentanyl + 2 mg morphine in 15 mL saline were given to Group bupivacaine‑fentanyl‑morphine (Group BFM) with no test dosing from the needle. No morphine was added to the subsequent epidural injections in Group BFM.Results: The total dose of bupivacaine was significantly lower in Group BFM relative to Group BF (P = 0.0001). The visual analogu scalescores at 15, 30, and 45 min were significantly lower in Group BF compared to thosein Group BFM (P = 0.0001, P = 0.001, and P = 0.006, respectively). The second stage of labor was significantly shorter in Group BFM relative to Group BF (P = 0.027 and P = 0.003, respectively). The satisfaction with analgesia following the first dose was higher in the nonmorphine group (P = 0.0001). However, maternal postpartum satisfaction was similar in both groups. Either nausea or vomiting was recorded in eight patients in Group BFM.Conclusion: We believe that epidural analgesia comprised of a low‑dose local anaesthetic and 2 mg morphine provides a painless labor that significantly reducesthe use of local anesthetic without changing the efficiency of the analgesic, ensuring the mother’s satisfaction without leading to an adverse effect on the mother or foetus, while mildly (but significantly) shortening the second stage of labor.Key words: Bupivacaine, epidural analgesia, fentanyl, morphine, painless labo

Design of Miniaturized Narrowband Absorbers Based on Resonant-Magnetic Inclusions

Cataloged from PDF version of article.In this paper, we present the design of miniaturized narrowband-microwave absorbers based on different kinds of magnetic inclusions. The operation of the proposed components originates from the resonance of a planar array of inclusions excited by an incoming wave with a given polarization. As in common absorber layouts, a 377 Omega resistive sheet is also used to absorb the electromagnetic energy of the impinging field. Since the planar array of magnetic inclusions behaves at its resonance as a perfect magnetic conductor, the resistive sheet is placed in close proximity of the resonating inclusions, without perturbing their resonance condition. In contrast to other typical absorber configurations presented in the literature, the absorber proposed in this paper is not backed by a metallic plate. This feature may be useful for stealth applications, as discussed thoroughly in the paper. The other interesting characteristic of the proposed absorbers is the subwavelength thickness, which has shown to depend only on the geometry of the basic resonant inclusions employed. At first, regular split-ring resonators (SSRs) disposed in an array configuration are considered and some application examples are presented. Absorbers based on SRRs are shown to reach thickness of the order of lambda(0)/20. In order to further squeeze the electrical thickness of the absorbers, multiple SRRs and spiral resonators are also used. The employment of such inclusions leads to the design of extremely thin microwave absorbers, whose thickness may even be close to lambda(0)/100. Finally, some examples of miniaturized absorbers suitable for a practical realization are proposed

Optically thin composite resonant absorber at the near-infrared band: a polarization independent and spectrally broadband configuration

Cataloged from PDF version of article.We designed, fabricated, and experimentally characterized thin absorbers utilizing both electrical and magnetic impedance matching at the near-infrared regime. The absorbers consist of four main layers: a metal back plate, dielectric spacer, and two artificial layers. One of the artificial layers provides electrical resonance and the other one provides magnetic resonance yielding a polarization independent broadband perfect absorption. The structure response remains similar for the wide angle of incidence due to the sub-wavelength unit cell size of the constituting artificial layers. The design is useful for applications such as thermal photovoltaics, sensors, and camouflage. (C)2011 Optical Society of Americ

Asymmetric Fabry-Perot-type transmission in photonic-crystal gratings with one-sided corrugations at a two-way coupling

Cataloged from PDF version of article.Strongly asymmetric Fabry-Perot-type transmission arising at the two-way coupling has been studied in the case of normal incidence for slabs of two-dimensional photonic crystals (PCs) with one-sided corrugations that are made of linear isotropic materials. Comparing to the scenario of unidirectional transmission known for the structures with broken spatial inversion symmetry that requires zero order being uncoupled, in the studied mechanism zero order is either the sole order or one of the orders that may be coupled to a Floquet-Bloch mode. Contrary to the earlier studies of asymmetric transmission at the coupled zero order, structures with nondeep corrugations are considered, which allow one to combine Fabry-Perot-type total-transmission maxima with diffractions in a desired way. At a proper choice of PC lattice and corrugation parameters, higher orders can dominate in Fabry-Perot-type transmission at the noncorrugated-side illumination and also at the total-transmission maxima, whereas only zero order contributes to the transmission at the corrugated-side illumination. As a result, strong asymmetry can be obtained without uncoupling of zero order but it invokes the unidirectional contribution of higher orders. The presented results show that the entire structure can be approximately decomposed into the two independent, regular and grating (nonregular), parts whose contributions to the transmission are additive. Multiple asymmetric transmission maxima can coexist with a rather high equivalent group index of refraction. Possible applications of the studied transmission mechanism are discussed

Chiral metamaterials with negative refractive index based on four "U" split ring resonators

A uniaxial chiral metamaterial is constructed by double-layered four "U" split ring resonators mutually twisted by 90 degrees. It shows a giant optical activity and circular dichroism. The retrieval results reveal that a negative refractive index is realized for circularly polarized waves due to the large chirality. The experimental results are in good agreement with the numerical results.Comment: 4 pages, 4 figures, Published as cover on AP

Probe of extra dimensions in gamma q->gamma q at the LHC

We have examined TeV scale effects of extra spatial dimensions through the processes gamma q-> gamma q where q=u,d,c,s,b, anti-u, anti-d, anti-c, anti-s, anti-b. These processes have been treated in a photon-proton collision via the main reaction pp-> p gamma p-> p gamma qX at the LHC. We have employed equivalent photon approximation for incoming photon beams and performed statistical analysis for various forward detector acceptances.Comment: 17 pages, 5 figure