286 research outputs found
SMATASY - A program for the model independent description of the Z resonance
SMATASY is an interface for the ZFITTER package and may be used for the model
independent description of the Z resonance at LEP 1 and SLC. It allows the
determination of the Z mass and width and its resonance shape parameters r and
j for cross-sections and their asymmetries. The r describes the peak height and
j the interference of the Z resonance with photon exchange in each scattering
channel and for , , , etc.
separately. Alternatively, the helicity amplitudes for a given scattering
channel may be determined. We compare our formalism with other model
independent approaches. The model independent treatment of QED corrections in
SMATASY is applicable also far away from the Z peak.Comment: 25 pages (LaTeX), 5 figures, 1 table, see also
http://www-zeuthen.desy.de/~riemann/ or
http://hpl3sn02.cern.ch/homepages/gruenew
A simple recurrent neural network for solution of linear programming: Application to a Microgrid
The aim of this paper is to present a simple new class of recurrent neural networks, which solves linear programming. It is considered as a sliding mode control problem, where the network structure is based on the Karush-Kuhn-Tucker (KKT) optimality conditions, and the KKT multipliers are the control inputs to be implemented with finite time stabilizing terms based on the unit control, instead of common used activation functions. Thus, the main feature of the proposed network is the fixed number of parameters despite of the optimization problem dimension, which means, the network can be easily scaled from a small to a higher dimension problem. The applicability of the proposed scheme is tested on real-time optimization of an electrical Microgrid prototype.Consejo Nacional de Ciencia y Tecnologí
A Fixed Time Convergent Dynamical System to Solve Linear Programming
The aim of this paper is to present a new dynamical system which solves linear programming. Its design is considered as a sliding mode control problem, where its structure is based on the Karush-Kuhn-Tucker optimality conditions, and its multipliers are the control inputs to be implemented by using fixed time stabilizing terms with vectorial structure, based on the unit control, instead of common terms used in other approaches. Thus, the main features of the proposed system are the fixed convergence time to the programming solution and the fixed parameters number despite of the optimization problem dimension. That is, there is a time independent to the initial conditions in which the system converges to the solution and, the proposed structure can be easily scaled from a small to a higher dimension problem. The applicability of the proposed scheme is tested on real-time optimization of an electrical Microgrid prototype.Consejo Nacional de Ciencia y Tecnologí
A recurrent neural network for real time electrical microgrid prototype optimization
The aim of this paper is to present a new class of recurrent neural networks, which solve linear programming. It is considered as a sliding mode control problem, where the network structure is based on the Karush-Kuhn-Tucker (KKT) optimality conditions, and the KKT multipliers are the control inputs to be implemented with fixed time stabilizing terms, instead of common used activation functions. Thus, the main feature of the proposed network is its fixed convergence time to the solution, which means, there it is a time independent to the initial conditions in which the network converges to the optimization solution. The applicability of the proposed scheme is tested on real-time optimization of an electrical microgrid prototype.Consejo Nacional de Ciencia y Tecnologí
Self-Assembly and Conformation of Tetrapyridilporphyrin on the Ag(111) Surface
We present a low-temperature scanning tunneling microscopy (STM) study on the supramolecular ordering of tetrapyridyl-porphyrin (TPyP) molecules on Ag(111). Vapor deposition in a wide substrate temperature range reveals that TPyP molecules easily diffuse and self-assemble into large, highly ordered chiral domains. We identify two mirror-symmetric unit cells, each containing two differently oriented molecules. From an analysis of the respective arrangement it is concluded that lateral intermolecular interactions control the packing of the layer, while its orientation is induced by the coupling to the substrate. This finding is corroborated by molecular mechanics calculations. High-resolution STM images recorded at 15 K allow a direct identification of intramolecular features. This makes it possible to determine the molecular conformation of TPYP on Ag(111). The pyridyl groups are alternately rotated out of the porphyrin plane by an angle of 60°
Life Cycle oriented Risk Management for PPP-Projects in Public Real Estate
Anlässlich der Bedeutung und Tragweite des Risikomanagements für die erfolgreiche Abwicklung von Public Private Partnership-Projekten wurde von Juni 2008 bis Oktober 2010 das Forschungsprojekt „Lebenszyklusorientiertes Risikomanagement für PPP-Projekte im öffentlichen Hochbau“ an der Bauhaus-Universität Weimar umgesetzt. Gefördert wurde das Forschungsprojekt aus den Mitteln der Forschungsinitiative „Zukunft Bau“, welche durch das Bundesministerium für Verkehr, Bau und Stadtentwicklung (BMVBS) und dem Bundesamt für Bauwesen und Raumordnung (BBR) als Projektträger gemeinsam durchgeführt wird. Das Ziel des Forschungsprojektes bestand in der Entwicklung eines Integrierten Risikomanagementsystems (abgekürzt: IRMS), das die PPP-Vertragspartner zu einem zielgerichteten und wirtschaftlichen Umgang mit den inkludierten Risiken befähigen soll. Darüber hinaus soll das System eine projektspezifische und innerhalb des gegebenen Handlungsspielraums optimale Risikoverteilung ermöglichen. Der Forschungsbericht untergliedert sich in vier Teile, welche die Arbeitsergebnisse des Forschungsprojektes strukturiert darstellen. Zunächst werden im ersten Teil des Forschungsberichtes die Ergebnisse einer empirischen Untersuchung zum Ist-Zustand des Risikomanagements in PPP-Projekten des öffentlichen Hochbaus als Grundlage für die weiteren Untersuchungen und Ergebnisse des Forschungsprojektes analysiert. Der zweite Teil des Forschungsprojektes beinhaltet ein Kompendium bzw. Werkzeugkasten der Methoden des Risikomanagements. In ihm werden die Verfahren zur Erlangung von risikobezogenen Erkenntnissen oder praktischen Ergebnissen dargestellt und hinsichtlich ihrer Eigenschaften analysiert. Darüber hinaus werden Allokationskriterien auf der Grundlage der den PPP-Vertragspartnern real zur Verfügung stehenden Informationen definiert, die als Basis sowohl für die Selektion vorteilhafter Risikobewältigungsmaßnahmen als auch für den Nachweis der Vorteilhaftigkeit der Übernahme von Risiken für Auftragnehmer im Risikomanagementprozess dienen. Durch die Anwendung dieser Allokationskriterien im IRMS kann eine optimale Risikoverteilung sowohl für den einzelnen Projektpartner als auch das Gesamtprojekt erreicht werden. Im dritten Teil wird das integrierte Risikomanagement-Prozessmodell über den gesamten Projektlebenszyklus eines PPP-Hochbauprojektes unter Berücksichtigung der relevanten PPP-Vertragspartner dargestellt und erläutert. Es stellt einen wesentlichen Beitrag zur Standardisierung dar und bietet die Möglichkeit für die Praxis, ein Verständnis für die Abläufe und Anforderungen der anderen Vertragspartner weiter zu entwickeln. Das Modell besteht aus drei Ebenen. Auf der ersten Ebene werden die Prozesse aller PPP-Vertragspartner und ihre Interaktion über den Projektlebenszyklus in einer globalen Prozesslandkarte dargestellt. Die zweite Ebene bildet die vertragspartnerspezifischen Prozesslandkarten ab. Den höchsten Detaillierungsgrad weist die dritte Ebene mit den vertragspartnerspezifischen Risikomanagementprozessen auf. Sie bildet die Integration der einzelnen Phasen des Risikomanagementprozesses in die bestehende Ablauforganisation der PPP-Vertragspartner in Form von Prozessflussdiagrammen ab. Von herausragender Bedeutung innerhalb des Risikoprozessmodells ist der Standardprozess Risikoallokation, welcher bei allen Vertragspartnern in den einzelnen Projektphasen verwendet wird. Abhängig von der jeweiligen Zielstellung seiner Verwendung befähigt er sowohl zur Ermittlung der optimalen Risikoallokation unter dem gegebenen Handlungsspielraum des Anwenders als auch zur Auswahl einer optimalen Risikobewältigung für ein Einzelrisiko bzw. Risikobündel innerhalb eines bestehenden Steuerungskonzeptes. Der vierte Teil führt die Erkenntnisse der vorhergehenden Bände in der exemplarischen Ausgestaltung des IRMS zusammen. Es besteht aus dem auf die PPP-Prozesse abgestimmten integrierten Risikomanagement-Prozessmodell, den zu den einzelnen Prozessen gehörenden Methoden sowie organisationsspezifischen Festlegungen. Um die Anwendbarkeit eines solchen IRMS aufzuzeigen, wird exemplarisch die methodische Ausgestaltung des Standardprozesses Risikoallokation vorgestellt
Injury Causes and Severity in Pediatric Traumatic Brain Injury Patients Admitted to the Ward or Intensive Care Unit: A Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) Study
Background: Traumatic brain injury (TBI) is the leading cause of death and disability in children. It includes a range of different pathologies that differ considerably from adult TBI. Analyzing and understanding injury patterns of pediatric TBI is essential to establishing new preventive efforts as well as to improve clinical management.Methods: The multi-center, prospectively collected CENTER-TBI core and registry databases were screened and patients were included when younger than 18 years at enrollment and admitted to the regular ward (admission stratum) or intensive care unit (ICU stratum) following TBI. Patient demographics, injury causes, clinical findings, brain CT imaging details, and outcome (GOSE at 6 months follow-up) were retrieved and analyzed. Injury characteristics were compared between patients admitted to the regular ward and ICU and multivariate analysis of factors predicting an unfavorable outcome (GOSE 1-4) was performed. Results from the core study were compared to the registry dataset which includes larger patient numbers but no follow-up data.Results: Two hundred and twenty seven patients in the core dataset and 687 patients in the registry dataset were included in this study. In the core dataset, road-traffic incidents were the most common cause of injury overall and in the ICU stratum, while incidental falls were most common in the admission stratum. Brain injury was considered serious to severe in the majority of patients and concurrent injuries in other body parts were very common. Intracranial abnormalities were detected in 60% of initial brain CTs. Intra- and extracranial surgical interventions were performed in one-fifth of patients. The overall mortality rate was 3% and the rate of unfavorable outcome 10%, with those numbers being considerably higher among ICU patients. GCS and the occurrence of secondary insults could be identified as independent predictors for an unfavorable outcome. Injury characteristics from the core study could be confirmed in the registry dataset.Conclusion: Our study displays the most common injury causes and characteristics of pediatric TBI patients that are treated in the regular ward or ICU in Europe. Road-traffic incidents were especially common in ICU patients, indicating that preventive efforts could be effective in decreasing the incidence of severe TBI in children.</div
On the breaking of a plasma wave in a thermal plasma: I. The structure of the density singularity
The structure of the singularity that is formed in a relativistically large
amplitude plasma wave close to the wavebreaking limit is found by using a
simple waterbag electron distribution function. The electron density
distribution in the breaking wave has a typical "peakon" form. The maximum
value of the electric field in a thermal breaking plasma is obtained and
compared to the cold plasma limit. The results of computer simulations for
different initial electron distribution functions are in agreement with the
theoretical conclusions.Comment: 21 pages, 12 figure
Molecular Nanoscience and Engineering on Surfaces
Molecular engineering of low-dimensional materials exploiting controlled self-assembly and positioning of individual atoms or molecules at surfaces opens up new pathways to control matter at the nanoscale. Our research thus focuses on the study of functional molecules and supramolecular architectures on metal substrates. As principal experimental tools we employ low-temperature scanning tunneling microscopy and spectroscopy. Here we review recent studies in our lab at UBC: Controlled manipulation of single CO molecules, self-assembled biomolecular nanogratings on Ag(111) and their use for electron confinement, as well as the organisation, conformation, metalation and electronic structure of adsorbed porphyrins
Transplantation of Neural Precursor Cells Attenuates Chronic Immune Environment in Cervical Spinal Cord Injury
Inflammation after traumatic spinal cord injury (SCI) is non-resolving and thus still present in chronic injury stages. It plays a key role in the pathophysiology of SCI and has been associated with further neurodegeneration and development of neuropathic pain. Neural precursor cells (NPCs) have been shown to reduce the acute and sub-acute inflammatory response after SCI. In the present study, we examined effects of NPC transplantation on the immune environment in chronic stages of SCI. SCI was induced in rats by clip-compression of the cervical spinal cord at the level C6-C7. NPCs were transplanted 10 days post-injury. The functional outcome was assessed weekly for 8 weeks using the Basso, Beattie, and Bresnahan scale, the CatWalk system, and the grid walk test. Afterwards, the rats were sacrificed, and spinal cord sections were examined for M1/M2 macrophages, T lymphocytes, astrogliosis, and apoptosis using immunofluorescence staining. Rats treated with NPCs had compared to the control group significantly fewer pro-inflammatory M1 macrophages and reduced immunodensity for inducible nitric oxide synthase (iNOS), their marker enzyme. Anti-inflammatory M2 macrophages were rarely present 8 weeks after the SCI. In this model, the sub-acute transplantation of NPCs did not support survival and proliferation of M2 macrophages. Post-traumatic apoptosis, however, was significantly reduced in the NPC group, which might be explained by the altered microenvironment following NPC transplantation. Corresponding to these findings, reactive astrogliosis was significantly reduced in NPC-transplanted animals. Furthermore, we could observe a trend toward smaller cavity sizes and functional improvement following NPC transplantation. Our data suggest that transplantation of NPCs following SCI might attenuate inflammation even in chronic injury stages. This might prevent further neurodegeneration and could also set a stage for improved neuroregeneration after SCI
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