163 research outputs found

    Adaptive model based control for wastewater treatment plants

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    In biological wastewater treatment, nitrogen and phosphorous are removed by activated sludge. The process requires oxygen input via aeration of the activated sludge tank. Aeration is responsible for about 60% of the energy consumption of a treatment plant. Hence optimization of aeration can contribute considerably to the increase of energy-efficiency in wastewater treatment. To this end, we introduce an adaptive model based control strategy for aeration called adaptive WOMBAT. The strategy is an improvement of the original WOMBAT, which has been successfully implemented at wastewater treatment plant Westpoort in Amsterdam. In this paper we propose to improve the physics-based model by introducing automatic parameter adaptation. In an experimental model setup the adaptive model based control algorithm proves to result in better effluent quality with less energy consumption. Moreover, it is able to react to the varying circumstances of a real treatment plant and can, therefore, operate without human supervision

    Occupancy rate

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    Integrated patient-to-room and nurse-to-patient assignment in hospital wards

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    Assigning patients to rooms and nurses to patients are critical tasks within hospitals that directly affect patient and staff satisfaction, quality of care, and hospital efficiency. Both patient-to-room assignments and nurse-to-patient assignments are typically agreed upon at the ward level, and they interact in several ways such as jointly determining the walking distances nurses must cover between different patient rooms. This motivates to consider both problems jointly in an integrated fashion. This paper presents the first optimization models and algorithms for the integrated patient-to-room and nurse-to-patient assignment problem. We provide a mixed integer programming formulation of the integrated problem that considers the typical objectives from the single problems as well as additional objectives that can only be properly evaluated when integrating both problems. Moreover, motivated by the inherent complexity that results from integrating these two NP-hard and already computationally challenging problems, we devise an efficient heuristic for the integrated patient-to-room and nurse-to-patient assignment problem. To evaluate the running time and quality of the solution obtained with the heuristic, we conduct extensive computational experiments on both artificial and real-world instances. The artificial instances are generated by a parameterized instance generator for the integrated problem that is made freely available

    Four applications of embodied cognition

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    This article presents the views of four sets of authors, each taking concepts of embodied cognition into problem spaces where the new paradigm can be applied. The first considers consequences of embodied cognition on the legal system. The second explores how embodied cognition can change how we interpret and interact with art and literature. The third examines how we move through archi- tectural spaces from an embodied cognition perspective. And the fourth addresses how music cogni- tion is influenced by the approach. Each contribution is brief. They are meant to suggest the potential reach of embodied cognition, increase the visibility of applications, and inspire potential avenues for research

    Integrated scheduling of tasks and gynecologists to improve patient appointment scheduling:a case study

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    Like many hospital departments, the gynecology department of the Jeroen Bosch Hospital experienced difficulties with scheduling outpatient appointments at the medically preferred times. Despite the time invested in creating the schedule, the compliance of the achieved schedules with the preferences of gynecologists is low, and the number of scheduled outpatient clinic hours is unbalanced over the weeks. To overcome this unbalanced scheduling, we develop a scheduling methodology that, opposed to existing methods, simultaneously assigns task types and gynecologists to shifts. This enables us to (1) explore the complete solution space to obtain better schedules, and (2) take into account different specializations and working hours of the gynecologists. To this end, we first present a Mixed Integer Linear Programming (MIP) approach for this scheduling problem that has the objective to increase compliance of the soft constraints. Preliminary results achieved with this MIP model show the potential of the chosen approach and were the motivation to develop two heuristic approaches, which are better suited for practical purposes. Based on several realistic test instances, the scheduling approaches appear promising for the hospital to apply for gynecologist scheduling, as they improve patient access times, comply better with preferences of the gynecologists, significantly reduce the time spent on creating the schedules, and do not require MIP solvers

    Loss of expression of FANCD2 protein in sporadic and hereditary breast cancer

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    Fanconi anemia (FA) is a recessive disorder associated with progressive pancytopenia, multiple developmental defects, and marked predisposition to malignancies. FA is genetically heterogeneous, comprising at least 12 complementation groups (A–M). Activation of one of the FA proteins (FANCD2) by mono-ubiquitination is an essential step in DNA damage response. As FANCD2 interacts with BRCA1, is expressed in proliferating normal breast cells, and FANCD2 knockout mice develop breast tumors, we investigated the expression of FANCD2 in sporadic and hereditary invasive breast cancer patients to evaluate its possible role in breast carcinogenesis. Two tissue microarrays of 129 and 220 sporadic breast cancers and a tissue microarray containing 25 BRCA1 germline mutation-related invasive breast cancers were stained for FANCD2. Expression results were compared with several clinicopathological variables and tested for prognostic value. Eighteen of 96 (19%) sporadic breast cancers and two of 21 (10%) BRCA1-related breast cancers were completely FANCD2-negative, which, however, still showed proliferation. In the remaining cases, the percentage of FANCD2-expressing cells correlated strongly with mitotic index and percentage of cells positive for the proliferation markers Ki-67 and Cyclin A. In immunofluorescence double staining, coexpression of FANCD2 and Ki-67 was apparent. In survival analysis, high FANCD2 expression appeared to be prognostically unfavorable for overall survival (p = 0.03), independent from other major prognosticators (p = 0.026). In conclusion, FANCD2 expression is absent in 10–20% of sporadic and BRCA1-related breast cancers, indicating that somatic inactivating (epi)genetic events in FANCD2 may be important in both sporadic and hereditary breast carcinogenesis. FANCD2 is of independent prognostic value in sporadic breast cancer

    The Cellular Phenotype of Roberts Syndrome Fibroblasts as Revealed by Ectopic Expression of ESCO2

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    Cohesion between sister chromatids is essential for faithful chromosome segregation. In budding yeast, the acetyltransferase Eco1/Ctf7 establishes cohesion during DNA replication in S phase and in response to DNA double strand breaks in G2/M phase. In humans two Eco1 orthologs exist: ESCO1 and ESCO2. Both proteins are required for proper sister chromatid cohesion, but their exact function is unclear at present. Since ESCO2 has been identified as the gene defective in the rare autosomal recessive cohesinopathy Roberts syndrome (RBS), cells from RBS patients can be used to elucidate the role of ESCO2. We investigated for the first time RBS cells in comparison to isogenic controls that stably express V5- or GFP-tagged ESCO2. We show that the sister chromatid cohesion defect in the transfected cell lines is rescued and suggest that ESCO2 is regulated by proteasomal degradation in a cell cycle-dependent manner. In comparison to the corrected cells RBS cells were hypersensitive to the DNA-damaging agents mitomycin C, camptothecin and etoposide, while no particular sensitivity to UV, ionizing radiation, hydroxyurea or aphidicolin was found. The cohesion defect of RBS cells and their hypersensitivity to DNA-damaging agents were not corrected by a patient-derived ESCO2 acetyltransferase mutant (W539G), indicating that the acetyltransferase activity of ESCO2 is essential for its function. In contrast to a previous study on cells from patients with Cornelia de Lange syndrome, another cohesinopathy, RBS cells failed to exhibit excessive chromosome aberrations after irradiation in G2 phase of the cell cycle. Our results point at an S phase-specific role for ESCO2 in the maintenance of genome stability
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