Decomposition Methods and Network Design Problems

Decomposition based approaches are recalled from primal and dual point of view. The possibility of building partially disaggregated reduced master problems is investigated. This extends the idea of aggregated-versus-disaggregated formulation to a gradual choice of alternative level of aggregation. Partial aggregation is applied to the linear multicommodity minimum cost flow problem. The possibility of having only partially aggregated bundles opens a wide range of alternatives with different trade-offs between the number of iterations and the required computation for solving it. This trade-off is explored for several sets of instances and the results are compared with the ones obtained by directly solving the natural node-arc formulation. An iterative solution process to the route assignment problem is proposed, based on the well-known Frank Wolfe algorithm. In order to provide a first feasible solution to the Frank Wolfe algorithm, a linear multicommodity min-cost flow problem is solved to optimality by using the decomposition techniques mentioned above. Solutions of this problem are useful for network orientation and design, especially in relation with public transportation systems as the Personal Rapid Transit. A single-commodity robust network design problem is addressed. In this, an undirected graph with edge costs is given together with a discrete set of balance matrices, representing different supply/demand scenarios. The goal is to determine the minimum cost installation of capacities on the edges such that the flow exchange is feasible for every scenario. A set of new instances that are computationally hard for the natural flow formulation are solved by means of a new heuristic algorithm. Finally, an efficient decomposition-based heuristic approach for a large scale stochastic unit commitment problem is presented. The addressed real-world stochastic problem employs at its core a deterministic unit commitment planning model developed by the California Independent System Operator (ISO).

Association between parental guilt and oral health problems in preschool children

Parents may feel guilty about their children's oral problems, which can affect their quality of life. The aim of this study was to assess the presence of parental guilt and its association with early childhood caries (ECC), traumatic dental injuries (TDI) and malocclusion (AMT) in preschool children. All 2 to 5 year-old children (N = 305), and their parents, seeking dental care at the University of São Paulo Dental School one-week Screening Programme, were asked to participate in the study, and 260 agreed. Children were examined by two calibrated dentists, and their parents answered a socioeconomic and ECOHIS questionnaire; the question on guilt was used as the dependent variable. Regression analyses examined the association between parental guilt and ECC, TDI, AMT and socioeconomic factors. A total of 35.8% of parents felt guilty. This was only associated with caries severity. No association was found between guilt and TDI, AMT or socioeconomic factors. ECC was present in 63.8% of the children; the mean (± sd) dmf-t score was 7.29 (± 2.78). Thus, the number of parents feeling guilty increases with the increase of their children's dental caries severity. Parental guilt is related to caries but is not associated with TDI or AMT.

[Erectile dysfunction in depression and under treatment with antidepressants -- current treatment options]

Erectile dysfunction (ED) is a common problem in the general population, but also a symptom of both treated and untreated depression. As a side effect of antidepressant medication, erectile dysfunction appears to be one of the principal reasons for discontinuing antidepressant treatment. Avoiding or switching antidepressants is problematic, as this may lead to an increase in depressive symptoms. Our review shows that oral phosphodiesterase inhibitors are an option in treating both ED resulting from depression and from antidepressant medication.

Economic Talc Deposits of Montana and Related Firing Problems

This thesis has to do with a study of the produc­tion of talc in Montana, describing the local geology of each deposit, and a description of the laboratory tests that were made on various grades of Montana talc in an attempt to determine why some grades of talc can be burned in solid forms while others must be ground, mixed with a binder and molded.

Executive compensation and executive incentive problems: an empirical analysis

The question of whether the design of the corporate executive pay package reflects an attempt to reduce agency costs between shareholders an managers is adressed. The components of senior executive pay are found to vary systematically across firms in a manner that cannot easily be explained by tax effects, and which would indicate that individual elements of pay are aimed at controlling for limited horizon and risk exposure problems. Managerial decisions and the structure of managerial pay therefore appear to be interrelated.

Expression and Regulation of Human Cytochrome P450 4F Isoforms in Tissue Samples and Under TNF-Alpha Challenges

CYP4F (Cytochrome P4504F) enzymes metabolize endogenous molecules including leukotrienes, prostaglandins and arachidonic acid. The involvement of these endogenous compounds in inflammation has led to the hypothesis that changes in the inflamed tissue environment may affect the expression of CYP4Fs during the pro-inflammatory state, which in turn may modulate inflammatory conditions during the anti-inflammatory state. We demonstrated that inflamed tissues have different levels of CYP4F isoform expression profiles in a number of human samples when compared to the average population. The CYP4F isoform expression levels change with the degree of inflammation present in tissue. Further investigation in cell culture studies revealed that inflammatory cytokines, in particular TNF-α, play a role in regulating the expression of the CYP4F family. One of the isoforms, CYP4F11, had different characteristics than that of the other five CYP4F family members. CYP4F11 metabolizes xenobiotics while the other isoforms metabolize endogenous compounds with higher affinity. CYP4F11 also was expressed at high quantities in the brain, and was up-regulated by TNF-α, while the other isoforms were not expressed at high quantities in the brain and were down-regulated by TNF-α. We identified the AP-1 protein of the JNK pathway as the signaling protein that causes significant increase in CYP4F11 expression. Since TNF-α stimulation causes a simultaneous activation of both JNK pathway and NF-κB signaling, we investigated further the role that NF-κB plays on expression of the CYP4F11 gene. We concluded that although there is a significant increase in CYP4F11 expression in the presence of TNF-α, the activation of NF-κB signaling inhibits CYP4F11 expression in a time dependent manner. The expression of CYP4F11 is only significantly increased after 24 hours of treatment with TNF-α; at shorter time points NF-κB signaling overpowers the JNK pathway activation. We believe that these findings may in the future lead to improved drug design for modulating inflammation.

Concentration, Working Speed and Memory: Cognitive Problems in Young Childhood Cancer Survivors and Their Siblings.

BACKGROUND Cognitive problems can have a negative effect on a person's education, but little is known about cognitive problems in young childhood cancer survivors (survivors). This study compared cognitive problems between survivors and their siblings, determined if cognitive problems decreased during recent treatment periods and identified characteristics associated with the presence of a cognitive problem in survivors. METHODS As part of the Swiss Childhood Cancer Survivor Study, a questionnaire was sent to all survivors, aged 8-20 years, registered in the Swiss Childhood Cancer Registry, diagnosed at age <16 years, who had survived ≥5 years. Parent-reported (aged 8-15 years) and self-reported (aged 16-20 years) cognitive problems (concentration, working speed, memory) were compared between survivors and siblings. Multivariable logistic regression was used to identify characteristics associated with cognitive problems in survivors. RESULTS Data from 840 survivors and 247 siblings were analyzed. More often than their siblings, survivors reported problems with concentration (12% vs. 6%; P = 0.020), slow working speed (20% vs. 8%; P = 0.001) or memory (33% vs. 15%; P < 0.001). Survivors from all treatment periods were more likely to report a cognitive problem than were siblings. Survivors of CNS tumors (OR = 2.82 compared to leukemia survivors, P < 0.001) and those who had received cranial irradiation (OR = 2.10, P = 0.010) were most severely affected. CONCLUSION Childhood cancer survivors, even those treated recently (2001-2005), remain at risk to develop cognitive problems, suggesting a need to improve therapies. Survivors with cognitive problems should be given the opportunity to enter special education programs. Pediatr Blood Cancer © 2014 Wiley Periodicals, Inc.