411 research outputs found

    Task Structure Abstraction

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    This paper explores the idea of using formalised abstraction as means of describing various operations on structured representations of planing, scheduling and resource allocation problems. We define a notion of structures on tasks, relations and resources. Each task consists of task parameters and an inductively defined substructure. The task parameters denote domain variables constrained by the relations of the structure while resources formalises resource constraints, typically presupposing the semantics of some global constraint. A notion of consistency of such structures is briefly outlined. We go on characterise properties of safeness and certain conservation properties on operations We claim that such properties are relevant to problem domains where tasks on several different types or levels of resources has to scheduled simultaneously or by partitioning the problem into several subproblems that has then to be coordinated. Finally we present, in some detail, a model of such a problem from the rail transport industry formalised as several task structures. We show how operations on these can be seen as solvers for the various subproblems but also used to transform a specification or a solution of one subproblem into a specification of an other one. We claim that properties of such operations can be used to characterise reasoning in coordination problems

    Decreased incidence of postoperative stroke following off-pump coronary artery bypass: Reply

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    ACOOR Rapport 2: Översikt av tekniker och metoder

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    I arbetet med att modellera ett produktionsplaneringsproblem i järnvägsindustrin har vi identifierat ett antal metoder och tekniker som vi hävdar är användbara även utanför järnvägsdomänen. I denna rapport presenterar vi kort problemställningarna i järnvägsdomänen, presenterar de viktigaste av de tekniker vi identifierat, använt och utvecklat samt indikerar en del andra problemdomäner för vilka vi bedömer att dessa tekniker skulle kunna användas

    Some Key Jurisprudential Issues of the Twenty-First Century

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    The objective of this study was to estimate the dispersal rate in an organism assumed to be confined to tree stands with unbroken continuity. We used the lichen-forming ascomycete Cliostomum corrugatum, which is largely confined to old oak stands. Five populations, with pairwise distances ranging from 6.5 to 83 km, were sampled in Ostergotland, south-eastern Sweden. DNA sequence data from an intron in the small subunit nuclear ribosomal RNA gene was obtained from 85 samples. Nearly all molecular variance (99.6%) was found within populations and there were no signs of isolation-by-distance. The absolute number of immigrants per population per generation (estimated to 30 years), inferred by Bayesian MCMC, was found to be between 1 and 5. Altogether, evidence suggests abundant gene flow in the history of our sample. A simulation procedure demonstrated that we cannot know whether effective dispersal is ongoing or if it ceased at the time when oaks started to decrease dramatically around 400 years BP. However, a scenario where effective dispersal ceased already at the time when the postglacial reinvasion of oak had reached the region around 6000 years BP is unlikely. Vegetation history suggests that the habitat of C. corrugatum was patchily distributed in the landscape since the early Holocene. Combined with the high dispersal rate estimate, this suggests that the species has been successful at frequently crossing distances of at least several kilometres and possibly that it has primarily been limited by the availability of habitat rather than by dispersal.Original Publication:Hakan Lattman, Louise Lindblom, Jan-Eric Mattsson, Per Milberg, Morten Skage and Stefan Ekman, Estimating the dispersal capacity of the rare lichen Cliostomum corrugatum, 2009, BIOLOGICAL CONSERVATION, (142), 8, 1870-1878.http://dx.doi.org/10.1016/j.biocon.2009.03.026Copyright: Elsevier Science B.V., Amsterdam.http://www.elsevier.com

    Boganmeldelser

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    Analysis of and prognostic information from disseminated tumour cells in bone marrow in primary breast cancer: a prospective observational study

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    Background Disseminated tumour cells (DTCs) in the bone marrow of patients with breast cancer have been identified as an independent predictor of poor prognosis in patients with non-metastatic disease. This prospective study aimed to evaluate the presence and prognostic value of DTCs in the bone marrow of female patients with primary breast cancer. Methods Between 1999 and 2003, bone marrow aspirates were obtained from patients at the time of surgery for primary invasive breast cancer. DTCs in bone marrow were identified using monoclonal antibodies against cytokeratins for detection of epithelial cells. The detection of DTCs was related to clinical follow-up with distant disease-free survival (DDFS) and breast cancer-specific survival as endpoints. Bone marrow aspirates from adult healthy bone marrow donors were analysed separately. Results DTCs were analysed in 401 patients, and cytokeratin-positive cells were found in 152 of these (38%). An immunofluorescence (IF) staining procedure was used in 327 patients, and immunocytochemistry (IC) was performed in 74 patients. The IF-based method resulted in 40% DTC-positive cases, whereas 30% were positive using IC (p = 0.11). The presence of DTCs in bone marrow was not significantly related to patient or tumour characteristics. The presence of DTCs was not a prognostic factor for DDFS (IF: hazards ratio [HR], 2.2; 95% confidence interval [CI], 0.63–2.2; p = 0.60; IC: HR, 0.84; 95% CI, 0.09–8.1; p = 0.88). Significant prognostic factors were lymph node metastases, oestrogen receptor positivity, Nottingham histological grade, and tumour size using Cox univariate analysis. The analyses were positive for epithelial cells in bone marrow from adult healthy donors in 19 (25%) samples. Conclusions The detection of DTCs in bone marrow in primary breast cancer was previously shown to be a predictor of poor prognosis. We were not able to confirm these results in a prospective cohort including unselected patients before the standard procedure was established. Future studies with a standardised patient protocol and improved technique for isolating and detecting DTCs may reveal the clinical applications of DTC detection in patients with micrometastases in the bone marrow.BioMed Central open acces

    No germline mutations in supposed tumour suppressor genes SAFB1 and SAFB2 in familial breast cancer with linkage to 19p

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    <p>Abstract</p> <p>Background</p> <p>The scaffold attachment factor B1 and B2 genes, <it>SAFB1/SAFB2 </it>(both located on chromosome 19p13.3) have recently been suggested as tumour suppressor genes involved in breast cancer development. The assumption was based on functional properties of the two genes and loss of heterozygosity of intragenic markers in breast tumours further strengthened the postulated hypothesis. In addition, linkage studies in Swedish breast cancer families also indicate the presence of a susceptibility gene for breast cancer at the 19p locus. Somatic mutations in <it>SAFB1/SAFB2 </it>have been detected in breast tumours, but to our knowledge no studies on germline mutations have been reported. In this study we investigated the possible involvement of <it>SAFB1/SAFB2 </it>on familiar breast cancer by inherited mutations in either of the two genes.</p> <p>Results</p> <p>Mutation analysis in families showing linkage to the <it>SAFB1/2 </it>locus was performed by DNA sequencing. The complete coding sequence of the two genes <it>SAFB1 </it>and <it>SAFB2 </it>was analyzed in germline DNA from 31 affected women. No missense or frameshift mutations were detected. One polymorphism was found in <it>SAFB1 </it>and eight polymorphisms were detected in <it>SAFB2</it>. MLPA-anlysis showed that both alleles of the two genes were preserved which excludes gene inactivation by large deletions.</p> <p>Conclusion</p> <p><it>SAFB1 </it>and <it>SAFB2 </it>are not likely to be causative of the hereditary breast cancer syndrome in west Swedish breast cancer families.</p
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