39,630 research outputs found
Measurement of the differential and double-differential Drell-Yan cross sections in proton-proton collisions at root s=7 TeV
No full textMeasurements of the differential and double-differential Drell-Yan cross sections are presented using an integrated luminosity of 4.5 (4.8) fb−1 in the dimuon (dielectron) channel of proton-proton collision data recorded with the CMS detector at the LHC at s√ = 7 TeV. The measured inclusive cross section in the Z-peak region (60–120 GeV) is σ(ℓℓ) = 986.4 ± 0.6 (stat.) ± 5.9 (exp. syst.) ± 21.7 (th. syst.) ± 21.7 (lum.) pb for the combination of the dimuon and dielectron channels. Differential cross sections dσ/dm for the dimuon, dielectron, and combined channels are measured in the mass range 15 to 1500 GeV and corrected to the full phase space. Results are also presented for the measurement of the double-differential cross section d2σ/dm d|y| in the dimuon channel over the mass range 20 to 1500 GeV and absolute dimuon rapidity from 0 to 2.4. These measurements are compared to the predictions of perturbative QCD calculations at next-to-leading and next-to-next-to-leading orders using various sets of parton distribution functions
Measurement of the low-mass Drell-Yan differential cross section at √s = 7 TeV using the ATLAS detector
No full textThe differential cross section for the process Z/γ ∗ → ℓℓ (ℓ = e, μ) as a function of dilepton invariant mass is measured in pp collisions at s√ = 7 TeV at the LHC using the ATLAS detector. The measurement is performed in the e and μ channels for invariant masses between 26 GeV and 66 GeV using an integrated luminosity of 1.6 fb−1 collected in 2011 and these measurements are combined. The analysis is extended to invariant masses as low as 12 GeV in the muon channel using 35 pb−1 of data collected in 2010. The cross sections are determined within fiducial acceptance regions and corrections to extrapolate the measurements to the full kinematic range are provided. Next-to-next-to-leading-order QCD predictions provide a significantly better description of the results than next-to-leading-order QCD calculations, unless the latter are matched to a parton shower calculation
Cloning and analysis of pppg1 , an inducible endopolygalacturonase gene from the oomycete plant pathogen Phytophthora parasitica
No full textSelection of internal control genes for real-time quantitative RT-PCR assays in the oomycete plant pathogen Phytophthora parasitica
No full textDistinguishing models of new physics at the LHC
No full textThe work presented in this thesis explores ways of distinguishing models of physics beyond the Standard Model at the Large Hadron Collider (LHC). The focus is puton supersymmetric models, in particular the Minimal Supersymmetric Standard Model (MSSM) and the E6-inspired Supersymmetric Standard Model (E6SSM), which are wellknown and well motivated models.The muon decay channel of the pseudoscalar and heavy Higgs bosons in the MSSM is studied. It is shown that these decays to muons, in some scenarios, make it possible to measure the widths of these Higgs bosons at the LHC. This is the only known way of measuring this width at the LHC. The decays to muons also allow for the mass to be measured accurately which together with the width measurement offers a uniqueopportunity to pin down the value of the model parameter tan Beta, which could be used to distinguish different scenarios within the MSSM and potentially in its extensions.Gluino cascade decays are investigated as a tool to distinguish the MSSM from more complex models, with the E6SSM as an example. It is shown that the longer cascadedecays of the E6SSM gluinos provide less missing transverse momentum and higher lepton multiplicity, implying the higher importance of multi-lepton searches at the LHC in models with a richer low-energy particle content. The three-lepton channel is shown to be a good discriminator between the models. In the case of a gluino discovery one would typically expect a signal in this channel if it is an E6SSM gluino but not if it is an MSSM gluino.Furthermore, the implications of limits from dark matter and Z' searches on the Higgs sector and other collider phenomenology are discussed. These implications are important to constrain and differentiate models. In addition, the contribution to fine-tuning from the Z' mass is discussed as an important measure of how attractive a model is, which should be considered by model builder
Lyman break galaxies and the star formation rate of the Universe at z ~ 6
No full textWe determine the space density of UV-luminous starburst galaxies at z≈ 6 using deep HST ACS SDSS-i′ (F775W) and SDSS-z′ (F850LP) and VLT ISAAC J and Ks band imaging of the Chandra Deep Field South. We find eight galaxies and one star with (i′−z′) > 1.5 to a depth of z′AB= 25.6 (an 8σ detection in each of the 3 available ACS epochs). This corresponds to an unobscured star formation rate of ≈15 h−270 M⊙ yr−1 at z= 5.9, equivalent to L* for the Lyman-break population at z= 3–4 (ΩΛ= 0.7, ΩM= 0.3). We are sensitive to star-forming galaxies at 5.6 ≲z≲ 7.0 with an effective comoving volume of ≈1.8 × 105h−370 Mpc3 after accounting for incompleteness at the higher redshifts due to luminosity bias. This volume should encompass the primeval subgalactic-scale fragments of the progenitors of about a thousand L* galaxies at the current epoch. We determine a volume-averaged global star formation rate of (6.7 ± 2.7) × 10−4h70 M⊙ yr−1 Mpc−3 at z∼ 6 from rest-frame UV selected starbursts at the bright end of the luminosity function: this is a lower limit because of dust obscuration and galaxies below our sensitivity limit. This measurement shows that at z∼ 6 the star formation density at the bright end is a factor of ∼6 times less than that determined by Steidel et al. for a comparable sample of UV-selected galaxies at z= 3–4, and so extends our knowledge of the star formation history of the Universe to earlier times than previous work and into the epoch where reionization may have occurred
Cultural identities as reflected in the literature of the Northern and Southern dynasties period (4th-6th centuries A.D.)
No full textDuring the period of the Northern and Southern dynasties of China identity questions became serious in a society thrown into disorder by political, religious and ethnic problems. This thesis uses three books written in the sixth century to
discuss how educated Chinese faced identity problems and how they dealt with them.
The Buddhist monk Huijiao, dealt with the problems of sinifying a foreign religion. He constructed many different identities in addition to the Buddhist one for the monks in his book Gaoseng zhuan, (Lives of Eminent Monks), a collection of biographies of Buddhist monks, to bring Buddhism closer to Chinese tradition and more acceptable by Confucian standards. Through the identity construction he
also made responses to anti-Buddhist ideas.
Yang Xuanzhi's Luoyang qielan ji, (Record of the Monasteries of Luoyang), deals with the identity problems of Chinese officials serving a Xianbei regime in
the north and of the short-lived capital of the Northern Wei in Luoyang. Yang reconstructed a Chinese identity for the lost capital as a true heir of Chinese tradition, as were the emperors, princes and officials who lived there. He created an identity defined not by ethnicity but by culture.
Yan Zhitui's Tanshi jiaxun, (Family Instruction of the Yan Clan), is a book which tells his descendants how to construct and maintain the future identity of his
own family. He drew on his own experience of recovering from repeated political catastrophes to set out an identity that would help the family to survive disordered times and maintain their status in society
Early-warning signal recognition methods in flawed sandstone subjected to uniaxial compression
No full textTo investigate the precursor information related to rock fracturing, a series of indoor uniaxial compression tests are conducted on flawed sandstone. Four methods of identifying potential precursors to rock catastrophic failure, namely, cumulative acoustic emission (AE) activity, AE b-value, inter-event time function, and critical slowing down, are discussed. The results show that the four precursory identification methods can reasonably identify the early-warning signal, subcritical failure, and final catastrophic failure of flawed sandstone involving the whole loading process. The minimum b-value is correspondingly obtained when the specimen approaches failure. The inter-event rate of AE multi-parameters shows a significant increase, following a power law distribution. By comparison with the other three precursor identification methods, the time intervals of AE parameters-based variance between the precursory signal and its corresponding tripping points become increasingly shortened. Additionally, the precursory characteristics of variance of AE multi-parameters are more accurate and reliable than that of autocorrelation coefficient
A privacy-preserving cryptosystem for IoT E-healthcare
No full textPrivacy preservation has become a prerequisite for modern applications in the cloud, social media, Internet of things (IoT), and E- healthcare systems. In general, health and medical data contain images and medical information about the patients and such personal data should be kept confidential in order to maintain the patients’ privacy. Due to limitations in digital data properties, traditional encryption schemes over textual and structural one-dimension data cannot be applied directly to e-health data. In addition, when personal data are sent over the open channels, patients may lose privacy of data contents. Hence, a secure lightweight keyframe extraction method is highly required to ensure timely, correct, and privacy-preserving e-health services. Besides this, it is inherently difficult to achieve a satisfied level of security in a cost-effective way while considering the constraints of real-time e-health applications. In this paper, we propose a privacy preserving chaos-based encryption cryptosystem for patients’ privacy protection. The proposed cryptosystem can protect patient's images from a compromised broker. In particular, we propose a fast probabilistic cryptosystem to secure medical keyframes that are extracted from wireless capsule endoscopy procedure using a prioritization method. The encrypted images produced by our cryptosystem exhibits randomness behavior, which guarantee computational efficiency as well as a highest level of security for the keyframes against various attacks. Furthermore, it processes the medical data without leaking any information, thus preserving patient's privacy by allowing only authorized users for decryption. The experimental results and security analysis from different perspectives verify the excellent performance of our encryption cryptosystem compared to other recent encryption schemes
Molecular evidence that aphid-transmitted Alpinia mosaic virus is a tentative member of the genus Macluravirus
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