331 research outputs found

    Soundness of workflow nets : classification, decidability, and analysis

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    Workflow nets, a particular class of Petri nets, have become one of the standard ways to model and analyze workflows. Typically, they are used as an abstraction of the workflow that is used to check the so-called soundness property. This property guarantees the absence of livelocks, deadlocks, and other anomalies that can be detected without domain knowledge. Several authors have proposed alternative notions of soundness and have suggested to use more expressive languages, e.g., models with cancellations or priorities. This paper provides an overview of the different notions of soundness and investigates these in the presence of different extensions of workflow nets. We will show that the eight soundness notions described in the literature are decidable for workflow nets. However, most extensions will make all of these notions undecidable. These new results show the theoretical limits of workflow verification. Moreover, we discuss some of the analysis approaches described in the literature

    De Arabische Regio, een Onzekere Toekomst

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    Modernity (Religion and Modernity

    Principles of Stakes Fairness in Sport

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    Fairness in sport is not just about assigning the top prizes to the worthiest competitors. It is also about the way the prize structure itself is organised. For many sporting competitions, although it may be acceptable for winners to receive more than losers, it can seem unfair for winners to take everything and for losers to get nothing. Yet this insight leaves unanswered some difficult questions about what stakes fairness requires and which principles of stakes fairness are appropriate for particular competitions. In this article I specify a range of different principles of stakes fairness (ten in total) that could regulate sporting competitions. I also put forward a theoretical method for pairing up appropriate principles of stakes fairness with given sporting competitions. Specifically, I argue that the underlying rationales for holding sporting competitions can provide useful guides for identifying appropriate principles of stakes fairness. I then seek to clarify and work through some of the implications of this method for a sample of real world controversies over sporting prize structures. I also attempt to refine the method in response to two possible objections from indeterminacy and relativism. Finally, I compare and contrast my conclusions with more general philosophical debates about justice

    MIR376A is a regulator of starvation-induced autophagy

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    Background: Autophagy is a vesicular trafficking process responsible for the degradation of long-lived, misfolded or abnormal proteins, as well as damaged or surplus organelles. Abnormalities of the autophagic activity may result in the accumulation of protein aggregates, organelle dysfunction, and autophagy disorders were associated with various diseases. Hence, mechanisms of autophagy regulation are under exploration. Methods: Over-expression of hsa-miR-376a1 (shortly MIR376A) was performed to evaluate its effects on autophagy. Autophagy-related targets of the miRNA were predicted using Microcosm Targets and MIRanda bioinformatics tools and experimentally validated. Endogenous miRNA was blocked using antagomirs and the effects on target expression and autophagy were analyzed. Luciferase tests were performed to confirm that 3’ UTR sequences in target genes were functional. Differential expression of MIR376A and the related MIR376B was compared using TaqMan quantitative PCR. Results: Here, we demonstrated that, a microRNA (miRNA) from the DlkI/Gtl2 gene cluster, MIR376A, played an important role in autophagy regulation. We showed that, amino acid and serum starvation-induced autophagy was blocked by MIR376A overexpression in MCF-7 and Huh-7 cells. MIR376A shared the same seed sequence and had overlapping targets with MIR376B, and similarly blocked the expression of key autophagy proteins ATG4C and BECN1 (Beclin 1). Indeed, 3’ UTR sequences in the mRNA of these autophagy proteins were responsive to MIR376A in luciferase assays. Antagomir tests showed that, endogenous MIR376A was participating to the control of ATG4C and BECN1 transcript and protein levels. Moreover, blockage of endogenous MIR376A accelerated starvation-induced autophagic activity. Interestingly, MIR376A and MIR376B levels were increased with different kinetics in response to starvation stress and tissue-specific level differences were also observed, pointing out to an overlapping but miRNA-specific biological role. Conclusions: Our findings underline the importance of miRNAs encoded by the DlkI/Gtl2 gene cluster in stress-response control mechanisms, and introduce MIR376A as a new regulator of autophagy

    Perinatal Mortality in Eastern Uganda: A Community Based Prospective Cohort Study

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    To achieve a child mortality reduction according to millennium development goal 4, it is necessary to considerably reduce neonatal mortality. We report stillbirth and early neonatal mortality risks as well as determinants of perinatal mortality in Eastern Uganda.A community-based prospective cohort study was conducted between 2006 and 2008. A total of 835 pregnant women were followed up for pregnancy outcome and survival of their children until 7 days after delivery. Mother's residence, age, parity, bed net use and whether delivery took place at home were included in multivariable regression analyses to identify risk factors for perinatal death.The stillbirth risk was 19 per 1,000 pregnancies and the early neonatal death risk 22 per 1,000 live births. Overall, the perinatal mortality risk was 41 [95%CI: 27, 54] per 1,000 pregnancies. Of the deaths, 47% followed complicated deliveries and 24% preterm births. Perinatal mortality was 63/1,000 pregnancies among teenage mothers, 76/1,000 pregnancies among nulliparous women and 61/1,000 pregnancies among women delivering at home who, after controlling for potential confounders, had a 3.7 (95%CI: 1.8, 7.4) times higher perinatal mortality than women who gave birth in a health facility. This association was considerably stronger among nulliparous women [RR 8.0 (95%CI: 2.9, 21.6)] than among women with a previous live birth [RR 1.8 (95%CI: 0.7, 4.5)]. All perinatal deaths occurred among women who did not sleep under a mosquito net. Women living in urban slums had a higher risk of losing their babies than those in rural areas [RR: 2.7 (95%CI: 1.4, 5.3)].Our findings strengthen arguments for ensuring that pregnant women have access to and use adequate delivery facilities and bed nets

    Strongly Coupled Magnetic and Electronic Transitions in Multivalent Strontium Cobaltites

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    The topotactic phase transition in SrCoOx (x = 2.5-3.0) makes it possible to reversibly transit between the two distinct phases, i.e. the brownmillerite SrCoO2.5 that is a room-temperature antiferromagnetic insulator (AFM-I) and the perovskite SrCoO3 that is a ferromagnetic metal (FM-M), owing to their multiple valence states. For the intermediate x values, the two distinct phases are expected to strongly compete with each other. With oxidation of SrCoO2.5, however, it has been conjectured that the magnetic transition is decoupled to the electronic phase transition, i.e., the AFM-to-FM transition occurs before the insulator-to-metal transition (IMT), which is still controversial. Here, we bridge the gap between the two-phase transitions by density-functional theory calculations combined with optical spectroscopy. We confirm that the IMT actually occurs concomitantly with the FM transition near the oxygen content x = 2.75. Strong charge-spin coupling drives the concurrent IMT and AFM-to-FM transition, which fosters the near room-T magnetic transition characteristic. Ultimately, our study demonstrates that SrCoOx is an intriguingly rare candidate for inducing coupled magnetic and electronic transition via fast and reversible redox reactions

    MicroRNA-211 Expression Promotes Colorectal Cancer Cell Growth In Vitro and In Vivo by Targeting Tumor Suppressor CHD5

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    Background: Chromodomain-helicase-DNA-binding protein 5 (CHD5) is a newly identified tumor suppressor that is frequently downregulated in a variety of human cancers. Our previous work revealed that the low expression of CHD5 in colorectal cancer is correlated with CHD5 promoter CpG island hypermethylation. In this study, we investigated the effect of microRNA-211 (miR-211)-regulated CHD5 expression on colorectal tumorigenesis. Methodology/Principal Findings: miR-211 was predicted to target CHD5 by TargetScan software analysis. A stably expressing exogenous miR-211 colorectal cancer cell line (HCT-116 miR-211) was generated using lentiviral transduction and used as a model for in vitro and in vivo studies. The expression level of miR-211 in HCT-116 miR-211 cells was upregulated by 16-fold compared to vector control cells (HCT-116 vector). Exogenous miR-211 directly binds to the 39-untranslated region (39-UTR) of CHD5 mRNA, resulting in a 50 % decrease in CHD5 protein level in HCT-116 miR-211 cells. The levels of cell proliferation, tumor growth, and cell migration of HCT-116 miR-211 cells were significantly higher than HCT-116 vector cells under both in vitro and in vivo conditions, as determined using the methods of MTT, colony formation, flow cytometry, scratch assay, and tumor xenografts, respectively. In addition, we found that enforced expression of miR-211 in HCT-116 cells was able to alter p53 pathway-associated regulatory proteins, such as MDM2, Bcl-2, Bcl-xL, and Bax. Conclusion/Significance: Our results demonstrate that CHD5 is a direct target of miR-211 regulation. Enforced expression o

    Downregulation of microRNA-383 is associated with male infertility and promotes testicular embryonal carcinoma cell proliferation by targeting IRF1

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    Our previous studies have shown that microRNA-383 (miR-383) expression is downregulated in the testes of infertile men with maturation arrest (MA). However, the underlying mechanisms of miR-383 involved in the pathogenesis of MA remain unknown. In this study, we showed that downregulation of miR-383 was associated with hyperactive proliferation of germ cells in patients with mixed patterns of MA. Overexpression of miR-383 in NT2 (testicular embryonal carcinoma) cells resulted in suppression of proliferation, G1-phase arrest and induction of apoptosis, whereas silencing of miR-383 reversed these effects. The effects of miR-383 were mediated through targeting a tumor suppressor, interferon regulatory factor-1 (IRF1), and miR-383 was negatively correlated with IRF1 protein expression in vivo. miR-383 inhibited IRF1 by affecting its mRNA stability, which subsequently reduced the levels of the targets of IRF1, namely cyclin D1, CDK2 and p21. Downregulation of IRF1 or cyclin D1, but not that of CDK2, enhanced miR-383-mediated effects, whereas silencing of p21 partially inhibited the effects of miR-383. Moreover, miR-383 downregulated CDK4 by increasing proteasome-dependent degradation of CDK4, which in turn resulted in an inhibition of phosphorylated retinoblastoma protein (pRb) phosphorylation. These results suggest that miR-383 functions as a negative regulator of proliferation by targeting IRF1, in part, through inactivation of the pRb pathway. Abnormal testicular miR-383 expression may potentiate the connections between male infertility and testicular germ cell tumor
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