Study of the Top-quark Pair Production in Association with a Bottom-quark Pair from Fast Simulations at the LHC

A large number of top quarks will be produced at the Large Hadron Collider (LHC) for Run II period. This will allow us to measure the rare processes from the top sector in great details. We present the study of the top-quark pair production in association with a bottom-quark pair (ttbb) from fast simulations for the Compact Muon Solenoid (CMS) experiment. The differential distributions of ttbb are compared with the top-quark pair production with two additional jets (ttjj) and with the production in association with the Higgs (ttH), where the Higgs decays to a bottom-quark pair. The significances of ttbb process in the dileptonic and semileptonic decay mode are calculated with the data corresponding to an integrated luminosity of 10 fb-1, which is foreseen to be collected in the early Run II period. This study will be an important input in searching for new physics beyond the standard model as well as in searching for ttH process where the Yukawa coupling with the top quark can be directly measured.Comment: 12 pages, 12 figure

Cryptanalysis of a Homomorphic Public-Key Cryptosystem

The aims of this research are to give a precise description of a new homomorphic public-key encryption scheme proposed by Grigoriev and Ponomarenko [7] in 2004 and to break Grigoriev and Ponomarenko homomorphic public-key cryptosystem. Firstly, we prove some properties of linear fractional transformations. We analyze the X_n-representation algorithm which is used in the decryption scheme of Grigoriev and Ponomarenko homomorphic public-key cryptosystem and by these properties of the linear fractional transformations, we correct and modify the X_n-representation algorithm. We implement the modified X_n-representation algorithm by programming it and we prove the correctness of the modified X_n-representation algorithm. Secondly, we find an explicit formula to compute the X(n,S)-representations of elements of the group \Lambda_n. The X(n,S)-representation algorithm is used in the decryption scheme of Grigoriev and Ponomarenko homomorphic public-key cryptosystem and we modify the X(n,S)-representation algorithm. We implement the modified X(n,S)-representation algorithm by programming it and we justify the modified X(n,S)-representation algorithm. By these two modified X_n-representation algorithm and X(n,S)-representation algorithm, we make its decryption scheme more efficient. Thirdly, by using those properties of the linear fractional transformations, we design new X_1-representation algorithms I and II and we mainly use these two X_1-representation algorithms to break Grigoriev and Ponomarenko homomorphic public-key cryptosystem. We implement the algorithms by programming them and we prove the correctness of these two algorithms. Fourthly, we analyze Grigoriev and Ponomarenko homomorphic public-key cryptosystem and we give a clear description of Grigoriev and Ponomarenko scheme with a practical example. We also consider implementation issues for its practical applications. Lastly, we show several attack methods with examples and experiments according as the attack methods and so we break Grigoriev and Ponomarenko homomorphic public-key cryptosystem

Inelastic scattering in a monolayer graphene sheet; a weak-localization study

Charge carriers in a graphene sheet, a single layer of graphite, exhibit much distinctive characteristics to those in other two-dimensional electronic systems because of their chiral nature. In this report, we focus on the observation of weak localization in a graphene sheet exfoliated from a piece of natural graphite and nano-patterned into a Hall-bar geometry. Much stronger chiral-symmetry-breaking elastic intervalley scattering in our graphene sheet restores the conventional weak localization. The resulting carrier-density and temperature dependence of the phase coherence length reveal that the electron-electron interaction including a direct Coulomb interaction is the main inelastic scattering factor while electron-hole puddles enhance the inelastic scattering near the Dirac point.Comment: 12 pages, 3 figures, submitted to PR

Increased fucosyl glycoconjugate by Mycoplasma hyopneumoniae enhances adherences of Pasteurella multocida type A in the ciliated epithelial cells of the respiratory tract

BACKGROUND: The objective of this study was to elucidate the pathogenic mechanisms of how Mycoplasma hyopneumoniae enhances secondary Pasteurella multocida type A infection which leads to porcine enzootic pneumonia in infected pigs. Sixteen pigs were experimentally infected with M. hyopneumoniae and then euthanized at 7, 14, 21 and 28 days post inoculation. In situ hybridization for M. hyopneumoniae DNA and Ulex europaeus agglutinin-I (UEA-I) lectin histochemistry for fucosyl glycoconjugate, was performed in serial lung sections to determine alteration of fucosyl glycoconjugate in M. hyopneumoniae-infected bronchial and bronchiolar epithelium. Bacterial overlay assay was performed to determine the affinity of P. multocida type A with L-fucose. RESULTS: The luminal surface of bronchial and bronchiolar epithelial cells that were stained with UEA-I always showed hybridization signals for M. hyopneumoniae but it was negative in the unaffected parts of the lung from M. hyopneumoniae-infected pigs and in lung from negative control pigs. Colocalization of M. hyopneumoniae and UEA-I was especially prominent in the luminal surface of bronchial and bronchiolar epithelial cells in serial section of lung. The mean number of M. hyopneumoniae-positive cells correlated with the mean number of UEA-I-positive cells in lungs from infected pigs throughout the experiment. All eight P. multocida type A isolates from naturally occurring enzootic pneumonia, bound strongly at levels of 2 μg and 5 μg of L-fucose. CONCLUSIONS: The results of the present study demonstrate that M. hyopneumoniae increases the L-fucose composition to enhance adherence of P. multocida type A to the bronchial and bronchiolar epithelial cells

A Low-Profile WLAN Antenna with Inductor and Tuning Stub for Broadband Impedance Matching

This paper presents a low-profile multiband antenna suitable for wireless local area networks (WLANs), using a chip inductor and tuning stub for broadband impedance matching. The proposed antenna is compact 12×10×1 mm3 and covers three bands: 2.4-GHz (2.400–2.484 GHz), 5.2-GHz (5.150–5.350 GHz), and 5.8-GHz (5.725–5.825 GHz). The measured 10-dB bandwidths are 12.0% (2.28–2.57 GHz) in the lower band for 2.4-GHz WLANs and 39.1% (4.81–7.15 GHz) in the upper band for 5 GHz-WLANs. The measured peak gain of the antenna is between 2.7 and 4.39 dBi and the radiation patterns are omnidirectional