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This paper proposes a reliability and performance analysis and modeling methodology for mission-oriented k-out-of-n systems. The system is assumed to suffer both independent internal failures and external common cause shocks, of which arrivals are both modeled by Poisson processes. Periodic missions are assigned to the system due to a fixed schedule. A performance measure is introduced based on the mission workload and number of components working in the system. By modeling the failure modes on such systems with a Markov chain model, the defined reliability and performance is given in analytical forms. In a following numerical example, we illustrate the reliability and performance for such systems by the proposed approach.

This paper presents a new approach for pupil localization in multi-view eyeballs under ordinary light conditions. There are two key steps. The first step is eye detection, which is obtained by facial key points using Active Shape Mode. Face detection is also used to provide the initial search area and enhance the searching speed for facial key points. The second step is the pupil localization process. In this stage, eye gray distribution obtained by sliding window technique is used to provide the coarse position of pupil, and similar local area analysis method is employed to provide pupil's fine position. A set of experiments on different eyeball positions are also presented. The experimental results show that the proposed method can perform well when the eye keeps normal and narrowed slightly, or gazes left, right and up. While the eye looks down, the localization effect needs to be improved further.

Histone proteins are essential for chromatin formation, and histone gene expression is coupled to DNA synthesis. In metazoans, the histone RNA binding protein HBP/SLBP is involved in post-transcriptional control of histone gene expression. In vitro assays have demonstrated that human HBP/SLBP is involved in histone mRNA 3′ end formation and translation. We have inhibited human HBP/SLBP expression by RNA interference to determine its function during the mitotic cell cycle. Inhibition of HBP/SLBP expression resulted in the inhibition of histone gene expression and DNA synthesis, the inhibition of cell cycle progression in S phase and the inhibition of cell proliferation. These findings indicate that human HBP/SLBP is essential for the coordinate synthesis of DNA and histone proteins and is required for progression through the cell division cycle.

Facial expression plays an important role in non-verbal social communication, emotion expression and affective recognition. To make the reorganization of facial expression more effectively, researchers try to recognize facial expression by the recognition of facial action units. In this paper, in order to identify lip AUs, we adopt Gabor wavelet transformation as the feature extraction method and Adaboost-SVM (combination of Adaboost and SVM) as the pattern classifier. Compared with the traditional non-cascaded Adboost algorithms in which the number of weak classifiers actually is fixed beforehand, a process of number optimization is added to ensure the minimum number of the weak classifies combination with the highest recognition rate. To test the effect of the given solution, 150 images from frontal faces for training and 100 images for prediction are collected. Compared with traditional SVM, the proposed system with Adaboost-SVM can not only improve the recognition accuracy from 79.0% to 83.0%, but also speed up AU classification process obviously.

This paper presents a new approach for pupil localization. The whole system can be divided into two stages: eyes detection and pupil localization. In the first stage, ASM method is used to locate the facial feature points, in which Adaboost algorithm is used to detect human face and provide the original searching position. In the second stage, gray distribution of the eyes is analyzed. The local area with lowest gray intensity is assumed the candidate of pupil. Finally, similar local area analysis technique is employed to adjust the position of the candidate pupil area. Experimental results validate the effects of our approach.

In metazoans, accurate replication of chromosomes is ensured by the coupling of DNA synthesis to the synthesis of histone proteins. Expression of replication-dependent histone genes is restricted to S-phase by a combination of cell cycle-regulated transcriptional and post-transcriptional control mechanisms and is linked to DNA replication by a poorly understood mechanism involving checkpoint kinases [Su, Gao, Schneider, Helt, Weiss, O'Reilly, Bohmann and Zhao (2004) EMBO J. 23, 1133–1143; Kaygun and Marzluff (2005) Nat. Struct. Mol. Biol. 12, 794–800]. Here we propose a model for the molecular mechanisms that link these two important processes within S-phase, and propose roles for multiple checkpoints in this mechanism.

Here, we report that the two recently identified E2F subunits, E2F7 and E2F8, are induced in cells treated with DNA-damaging agents where they have an important role in dictating the outcome of the DNA-damage response. The DNA-damage-dependent induction coincides with the binding of E2F7 and E2F8 to the promoters of certain E2F-responsive genes, most notably that of the E2F1 gene, in which E2F7 and E2F8 coexist in a DNA-binding complex. As a consequence, E2F7 and E2F8 repress E2F target genes, such as E2F1, and reducing the level of each subunit results in an increase in E2F1 expression and activity. Importantly, depletion of either E2F7 or E2F8 prevents the cell-cycle effects that occur in response to DNA damage. Thus, E2F7 and E2F8 act upstream of E2F1, and influence the ability of cells to undergo a DNA-damage response. E2F7 and E2F8, therefore, underpin the DNA-damage response.

DNA and histone synthesis are coupled and ongoing replication is required to maintain histone gene expression. Here, we expose S phase–arrested cells to the kinase inhibitors caffeine and LY294002. This uncouples DNA replication from histone messenger RNA (mRNA) abundance, altering the efficiency of replication stress–induced histone mRNA down-regulation. Interference with caffeine-sensitive checkpoint kinases ataxia telangiectasia and Rad3 related (ATR)/ataxia telangiectasia mutated (ATM) does not affect histone mRNA down- regulation, which indicates that ATR/ATM alone cannot account for such coupling. LY294002 potentiates caffeine's ability to uncouple histone mRNA stabilization from replication only in cells containing functional DNA-activated protein kinase (DNA-PK), which indicates that DNA-PK is the target of LY294002. DNA-PK is activated during replication stress and DNA-PK signaling is enhanced when ATR/ATM signaling is abrogated. Histone mRNA decay does not require Chk1/Chk2. Replication stress induces phosphorylation of UPF1 but not hairpin-binding protein/stem-loop binding protein at S/TQ sites, which are preferred substrate recognition motifs of phosphatidylinositol 3-kinase–like kinases, which indicates that histone mRNA stability may be directly controlled by ATR/ATM- and DNA-PK–mediated phosphorylation of UPF1.