2,482 research outputs found

    Chemical potentials of light flavor quarks from yield ratios of negative to positive particles in Au+Au collisions at RHIC

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    The transverse momentum spectra of π−\pi^{-}, π+\pi^{+}, K−K^{-}, K+K^{+}, pˉ\bar{p}, and pp produced in Au+Au collisions at center-of-mass energy sNN=7.7\sqrt{s_{NN}}=7.7, 11.5, 19.6, 27, 39, 62.4, 130, and 200200 GeV are analyzed in the framework of a multisource thermal model. The experimental data measured at midrapidity by the STAR Collaboration are fitted by the (two-component) standard distribution. The effective temperature of emission source increases obviously with the increase of the particle mass and the collision energy. At different collision energies, the chemical potentials of up, down, and strange quarks are obtained from the antiparticle to particle yield ratios in given transverse momentum ranges available in experiments. With the increase of logarithmic collision energy, the chemical potentials of light flavor quarks decrease exponentially.Comment: 9 pages, 2 figures. Advances in High Energy Physics, accepte

    Boomerang Connectivity Table Revisited. Application to SKINNY and AES

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    The boomerang attack is a variant of differential cryptanalysis which regards a block cipher E as the composition of two sub-ciphers, i.e., E = E1 o E0, and which constructs distinguishers for E with probability p2q2 by combining differential trails for E0 and E1 with probability p and q respectively. However, the validity of this attack relies on the dependency between the two differential trails. Murphy has shown cases where probabilities calculated by p2q2 turn out to be zero, while techniques such as boomerang switches proposed by Biryukov and Khovratovich give rise to probabilities greater than p2q2. To formalize such dependency to obtain a more accurate estimation of the probability of the distinguisher, Dunkelman et al. proposed the sandwich framework that regards E as Ẽ1 o Em o Ẽ0, where the dependency between the two differential trails is handled by a careful analysis of the probability of the middle part Em. Recently, Cid et al. proposed the Boomerang Connectivity Table (BCT) which unifies the previous switch techniques and incompatibility together and evaluates the probability of Em theoretically when Em is composed of a single S-box layer. In this paper, we revisit the BCT and propose a generalized framework which is able to identify the actual boundaries of Em which contains dependency of the two differential trails and systematically evaluate the probability of Em with any number of rounds. To demonstrate the power of this new framework, we apply it to two block ciphers SKINNY and AES. In the application to SKINNY, the probabilities of four boomerang distinguishers are re-evaluated. It turns out that Em involves5 or 6 rounds and the probabilities of the full distinguishers are much higher than previously evaluated. In the application to AES, the new framework is used to exclude incompatibility and find high probability distinguishers of AES-128 under the related-subkey setting. As a result, a 6-round distinguisher with probability 2−109.42 is constructed. Lastly, we discuss the relation between the dependency of two differential trails in boomerang distinguishers and the properties of components of the cipher

    Boomerang Connectivity Table Revisited

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    The boomerang attack is a variant of differential cryptanalysis which regards a block cipher EE as the composition of two sub-ciphers, i.e., E=E1∘E0E=E_1\circ E_0, and which constructs distinguishers for EE with probability p2q2p^2q^2 by combining differential trails for E0E_0 and E1E_1 with probability pp and qq respectively. However, the validity of this attack relies on the dependency between the two differential trails. Murphy has shown cases where probabilities calculated by p2q2p^2q^2 turn out to be zero, while techniques such as boomerang switches proposed by Biryukov and Khovratovich give rise to probabilities greater than p2q2p^2q^2. To formalize such dependency to obtain a more accurate estimation of the probability of the distinguisher, Dunkelman et al. proposed the sandwich framework that regards EE as E1~∘Em∘E0~\tilde{E_1}\circ E_m \circ \tilde{E_0}, where the dependency between the two differential trails is handled by a careful analysis of the probability of the middle part EmE_m. Recently, Cid et al. proposed the Boomerang Connectivity Table (BCT) which unifies the previous switch techniques and incompatibility together and evaluates the probability of EmE_m theoretically when EmE_m is composed of a single S-box layer. In this paper, we revisit the BCT and propose a generalized framework which is able to identify the actual boundaries of EmE_m which contains dependency of the two differential trails and systematically evaluate the probability of EmE_m with any number of rounds. To demonstrate the power of this new framework, we apply it to two block ciphers SKNNY and AES. In the application to SKNNY, the probabilities of four boomerang distinguishers are re-evaluated. It turns out that EmE_m involves 5 or 6 rounds and the probabilities of the full distinguishers are much higher than previously evaluated. In the application to AES, the new framework is used to exclude incompatibility and find high probability distinguishers of AES-128 under the related-subkey setting. As a result, a 6-round distinguisher with probability 2−109.422^{-109.42} is constructed. Lastly, we discuss the relation between the dependency of two differential trails in boomerang distinguishers and the properties of components of the cipher

    A Novel Inward Gradient Self-Lubrication Layer with Soft Alloys and Its Lubricating Mechanism

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    A novel ceramic composite inward gradient distribution layer has been developed. The layer is a lubricating layer in which soft-metal lubricants are compounded into the ceramic matrix by high frequency induction infiltrating method. The design of the layer and its lubricating mechanism are investigated in the paper. The results show that the property of the layer greatly depends on the wetting angle of the soft-metal lubricants on the matrix and the proportion of Ag, Cu, Sn, and Pb as well as the infiltrating parameters. Based on a lot of experiments, a novel inward gradient layer with Pb28Sn19Ag6Cu has been developed. The layer has an excellent lubricating property (friction coefficient about 0.2~0.3 at 600°C). The research reveals the lubricating mechanism, observing the phenomenon that the soft-metal in the matrix diffuses out of the frictional surface, and measures the lubricating film thickness as about 20 μm on the worn surface

    Involvement of AmphiREL, a Rel-like gene identified in Brachiastoma belcheri, in LPS-induced response: Implication for evolution of Rel subfamily genes

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    AbstractRel/NF-κB family genes are important transcriptional factors regulating vital activities of immunity response, but no Rel/NF-κB gene has been identified in amphioxus. In this study, we have not only identified and characterized a Rel-like gene from Brachiastoma belcheri, but also extensively studied the evolution of Rel gene subfamily. We found that: 1) the amphioxus genome contains an AmphiREL gene encoding a Rel/NF-κB homolog, and AmphiREL gene was involved in the innate immune response of LPS stimulation in amphioxus. 2) Gene synteny comparison and structure comparison suggested that AmphiREL is an orthologous gene of human RELB, and is a paralogous gene of human RELA and REL. 3) Structural changes of Rel subfamily proteins are diverse during the evolution process, and imply their functional diversity. 4) The Rel subfamily genes have undergone very strong purifying selection. Together, our results provide important clues for understanding the evolution and function of Rel subfamily genes

    The complete mitochondrial genome of the rodent intra-arterial nematodes Angiostrongylus cantonensis and Angiostrongylus costaricensis

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    The two rodent intra-arterial nematodes, Angiostrongylus cantonensis and Angiostrongylus costaricensis, can cause human ill-health. The present study aimed to characterize and compare the mitochondrial (mt) genomes of these two species, and clarify their phylogenetic relationship and the position in the phylum Nematoda. The complete mt genomes of A. cantonensis and A. costaricensis are 13,497 and 13,585bp in length, respectively. Hence, they are the smallest in the class of Chromadorea characterized thus far. Like many nematode species in the class of Chromadorea, they encode 12 proteins, 22 transfer RNAs, and two ribosomal RNAs. All genes are located on the same strand. Nucleotide identity of the two mt genomes is 81.6%, ranging from 77.7% to 87.1% in individual gene pairs. Our mt genome-wide analysis identified three major gene arrangement patterns (II-1, II-2, and II-3) from 48 nematode mt genomes. Both patterns II-1 and II-2 are distinct from pattern II-3, which covers the Spirurida, supporting a closer relationship between Ascaridida and Strongylida rather than Spirurida. Thymine (T) was highly concentrated on coding strands in Chromadorea, but balanced between the two strands in Enoplea, probably due to the gene arrangement pattern. Interestingly, the gene arrangement pattern of mt genomes and phylogenetic analysis based on concatenated amino acids indicated a closer relationship between the order Ascaridida and Rhabditida rather than Spirurida as indicated in previous studies. These discrepancies call for new research, reassessing the position of the order of Ascaridida in the phylogenetic tree. Once consolidated, the findings are important for population genetic studies and target identificatio
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