Optimal control problems with delays in state and control and mixed control-state constraints

Optimal control problems with delays in state and control variables are studied. Constraints are imposed as mixed control-state inequality constraints. Necessary optimality conditions in the form of Pontryagin's minimum principle are established. The proof proceeds by augmenting the delayed control problem to a nondelayed problem with mixed terminal boundary conditions to which Pontryagin's minimum principle is applicable. Discretization methods for the delayed control problem are discussed which amount to solving a large-scale nonlinear programming problem. It is shown that the Lagrange multipliers associated with the programming problem provide a consistent discretization of the advanced adjoint equation for the delayed control problem. An analytical example and two numerical examples from chemical engineering and economics illustrate the results

Das Bistum Konstanz 1. Das Stift St. Stephan in Konstanz

Helmut Maurer, Das Bistum Konstanz 1: Das Stift St. Stephan in Konstanz (Germania Sacra N. F. 15), Berlin/New York 1982

Das Bistum Konstanz 5. Die Konstanzer Bischöfe vom Ende des 6. Jahrhunderts bis 1206

Helmut Maurer, Das Bistum Konstanz 5 [nicht 2!]: Konstanzer Bischöfe 6. Jahrhundert bis 1206 (Germania Sacra N. F. 42,1), Berlin/New York 2003

Celiac axis infusion chemotherapy in advanced nonresectable pancreatic cancer

Summary: Conclusion: Based on these data we suggest that regional intra-arterial chemotherapy for advanced pancreatic cancer seems not to be superior to common treatment modalities, such as combined radiochemotherapy. Background: The prognosis for advanced pancreatic cancer is very poor. No standard treatment is available. Recently, better survival and quality of life was reported from regional cancer treatment via celiac axis infusion. In an attempt to confirm these results we conducted a phase II study of intra-arterial chemotherapy for nonresectable pancreatic cancer. Methods: From May 1994 to February 1995, 12 consecutive patients with biopsy-proven advanced ductal carcinoma of the exocrine pancreas were given intra-arterial infusions consisting of Mitoxantrone, 5-FU+ folinic acid, and Cisplatin via a transfemorally placed catheter in the celiac axis. Six patients were classified as UICC stage III and six as stage IV with the liver as the sole site of distant metastasis. Nine patients had primary and three had recurrent pancreatic carcinoma after a Whipple procedure. Nonresectability of primary tumors was assessed in all patients by laparotomy or laparoscopy. Results: A total of 31 cycles of chemotherapy (mean 2.6 cycles/patient) was administered. Catheter placement was technically feasible in all cycles. A groin hematoma was the only catheter complication. The follow-up by CT sans at 2-mo intervals revealed partial remission in 1 patient (8%), temporary stable disease in 4 patients (33%), and disease progression in 7 patients (58%). The same response was obtained after analyzing the CA 19-9 course. Median survival in stage III patients was 8.5 mo (3-12 mo) and in stage IV patients 5 mo (2-11 mo). Toxicity according to WHO criteria consisted of grade III (4 events), grade II (10 events), and grade I (17 events), mainly resulting from leucopenia and diarrhea/vomiting. Nine of 11 patients experienced temporary relief of pain immediately after regional treatmen

Implementation of a Wiki-based Information and Communication System for Academia Europaea

In recent years, online collaboration tools such as wikis have experienced a tremendous expansion. Their success and popularity is due to their simple and efficient content creation facilities. Moreover, the formatting syntax is basically easy to learn allowing users to easily create and edit web content and thus share knowledge with each other.Despite these advantages, the content creation process is still obscure if authors belong to a computer inexperienced user group. In this paper we present our experiences, challenges, and problems with a specific application of a wiki-based system called the Academia Europaea Information and Communication System. Furthermore, key solutions for bypassing user interaction barriers are discussed throughout this paper

Optimal control of normalized simr models with vaccination and treatment

We study a model based on the so called SIR model to control the spreading of a disease in a varying population via vaccination and treatment. Since we assume that medical treatment is not immediate we add a new compartment, M, to the SIR model. We work with the normalized version of the proposed model. For such model we consider the problem of steering the system to a specified target. We consider both a fixed time optimal control problem with L-1 cost and the minimum time problem to drive the system to the target. In contrast to the literature, we apply different techniques of optimal control to our problems of interest. Using the direct method, we first solve the fixed time problem and then proceed to validate the computed solutions using both necessary conditions and second order sufficient conditions. Noteworthy, we perform a sensitivity analysis of the solutions with respect to some parameters in the model. We also use the Hamiltonian Jacobi approach to study how the minimum time function varies with respect to perturbations of the initial conditions. Additionally, we consider a multi-objective approach to study the trade off between the minimum time and the social costs of the control of diseases. Finally, we propose the application of Model Predictive Control to deal with uncertainties of the model

The functional genome of CA1 and CA3 neurons under native conditions and in response to ischemia

<p>Abstract</p> <p>Background</p> <p>The different physiological repertoire of CA3 and CA1 neurons in the hippocampus, as well as their differing behaviour after noxious stimuli are ultimately based upon differences in the expressed genome. We have compared CA3 and CA1 gene expression in the uninjured brain, and after cerebral ischemia using laser microdissection (LMD), RNA amplification, and array hybridization.</p> <p>Results</p> <p>Profiling in CA1 vs. CA3 under normoxic conditions detected more than 1000 differentially expressed genes that belong to different, physiologically relevant gene ontology groups in both cell types. The comparison of each region under normoxic and ischemic conditions revealed more than 5000 ischemia-regulated genes for each individual cell type. Surprisingly, there was a high co-regulation in both regions. In the ischemic state, only about 100 genes were found to be differentially expressed in CA3 and CA1. The majority of these genes were also different in the native state. A minority of interesting genes (e.g. inhibinbetaA) displayed divergent expression preference under native and ischemic conditions with partially opposing directions of regulation in both cell types.</p> <p>Conclusion</p> <p>The differences found in two morphologically very similar cell types situated next to each other in the CNS are large providing a rational basis for physiological differences. Unexpectedly, the genomic response to ischemia is highly similar in these two neuron types, leading to a substantial attenuation of functional genomic differences in these two cell types. Also, the majority of changes that exist in the ischemic state are not generated de novo by the ischemic stimulus, but are preexistant from the genomic repertoire in the native situation. This unexpected influence of a strong noxious stimulus on cell-specific gene expression differences can be explained by the activation of a cell-type independent conserved gene-expression program. Our data generate both novel insights into the relation of the quiescent and stimulus-induced transcriptome in different cells, and provide a large dataset to the research community, both for mapping purposes, as well as for physiological and pathophysiological research.</p