105 research outputs found

    An evolutionary approach to a combined mixed integer programming model of seaside operations as arise in container ports

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    This paper puts forward an integrated optimisation model that combines three distinct problems, namely berth allocation, quay crane assignment, and quay crane scheduling that arise in container ports. Each one of these problems is difficult to solve in its own right. However, solving them individually leads almost surely to sub-optimal solutions. Hence, it is desirable to solve them in a combined form. The model is of the mixed-integer programming type with the objective being to minimize the tardiness of vessels and reduce the cost of berthing. Experimental results show that relatively small instances of the proposed model can be solved exactly using CPLEX. Large scale instances, however, can only be solved in reasonable times using heuristics. Here, an implementation of the genetic algorithm is considered. The effectiveness of this implementation is tested against CPLEX on small to medium size instances of the combined model. Larger size instances were also solved with the genetic algorithm, showing that this approach is capable of finding the optimal or near optimal solutions in realistic times

    Clinical significance of Neutrophil gelatinase-associated lipocalin(NGAL) expression in primary rectal cancer

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    <p>Abstract</p> <p>Background</p> <p>Emerging evidence has demonstrated that Neutrophil gelatinase-associated lipocalin (NGAL) is up-regulated in multiple malignancies, including oesophagus cancer, and plays a critical role in tumorigenesis and progression. However, till now, little is known about the role of NGAL in human rectal cancer. Its association with clinicopathologic characteristics and expression of MMP-9, one of its target genes, has not been reported systematically in rectal cancer. Therefore, to further determine the potential involvement of NGAL in rectal cancer, we have evaluated the expression level of NGAL mRNA by real time RT-PCR, and further elucidated the correlation of NGAL mRNA expression with clinicopathologic features and MMP-9 in rectal cancer.</p> <p>Methods</p> <p>100 paired samples of rectal cancer and adjacent normal tissues obtained from inpatients undergoing surgical operation were allocated into two groups (cancer group and control group). The mRNA expression of NGAL and MMP-9 was determined by real-time RT-PCR. The association between their expression and clinicopathological characteristics of rectal cancer were analysised.</p> <p>Results</p> <p>Among the 100 rectal cancers, 69 cases of NGAL mRNA up-regulation were observed. NGAL mRNA up-regulation was positively correlated with MMP-9 (<it>r</it><sub>s </sub>= 0.393, <it>p </it>< 0.001). In rectal cancer, NGAL mRNA overexpression was significantly associated with depth of invasion (<it>p </it>= 0.028), lymph node metastasis (<it>p </it>= 0.009), venous involvement (<it>p </it>= 0.023) and advanced pTNM stage (<it>p </it>= 0.011).</p> <p>Conclusion</p> <p>In human rectal cancer, NGAL mRNA expression was elevated. NGAL mRNA up-regulation was correlated significantly with tumor progression and MMP-9 mRNA overexpression in rectal cancer, suggesting a more aggressive phenotype. NGAL could be used for rectal cancer characterization.</p

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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    Measurement of the bbb\overline{b} dijet cross section in pp collisions at s=7\sqrt{s} = 7 TeV with the ATLAS detector

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