Automatisierte Berechnung von Feynman-Graphen

Die Berechnung von experimentell überprüfbaren Vorhersagen aus dem Standardmodell mit Hilfe störungstheoretischer Methoden ist schwierig. Die Herausforderungen liegen in der Berechnung immer komplizierterer Feynman-Integrale und dem zunehmenden Umfang der Rechnungen für Streuprozesse mit vielen Teilchen. Neue mathematische Methoden müssen daher entwickelt und die zunehmende Komplexität durch eine Automatisierung der Berechnungen gezähmt werden. In Kapitel 2 wird eine kurze Einführung in diese Thematik gegeben. Die nachfolgenden Kapitel sind dann einzelnen Beiträgen zur Lösung dieser Probleme gewidmet. In Kapitel 3 stellen wir ein Projekt vor, das für die Analysen der LHC-Daten wichtig sein wird. Ziel des Projekts ist die Berechnung von Einschleifen-Korrekturen zu Prozessen mit vielen Teilchen im Endzustand. Das numerische Verfahren wird dargestellt und erklärt. Es verwendet Helizitätsspinoren und darauf aufbauend eine neue Tensorreduktionsmethode, die Probleme mit inversen Gram-Determinanten weitgehend vermeidet. Es wurde ein Computerprogramm entwickelt, das die Berechnungen automatisiert ausführen kann. Die Implementierung wird beschrieben und Details über die Optimierung und Verifizierung präsentiert. Mit analytischen Methoden beschäftigt sich das vierte Kapitel. Darin wird das xloopsnosp-Projekt vorgestellt, das verschiedene Feynman-Integrale mit beliebigen Massen und Impulskonfigurationen analytisch berechnen kann. Die wesentlichen mathematischen Methoden, die xloops zur Lösung der Integrale verwendet, werden erklärt. Zwei Ideen für neue Berechnungsverfahren werden präsentiert, die sich mit diesen Methoden realisieren lassen. Das ist zum einen die einheitliche Berechnung von Einschleifen-N-Punkt-Integralen, und zum anderen die automatisierte Reihenentwicklung von Integrallösungen in höhere Potenzen des dimensionalen Regularisierungsparameters $epsilon$. Zum letzteren Verfahren werden erste Ergebnisse vorgestellt. Die Nützlichkeit der automatisierten Reihenentwicklung aus Kapitel 4 hängt von der numerischen Auswertbarkeit der Entwicklungskoeffizienten ab. Die Koeffizienten sind im allgemeinen Multiple Polylogarithmen. In Kapitel 5 wird ein Verfahren für deren numerische Auswertung vorgestellt. Dieses neue Verfahren für Multiple Polylogarithmen wurde zusammen mit bekannten Verfahren für andere Polylogarithmus-Funktionen als Bestandteil der CC-Bibliothek ginac implementiert.

AN EXPERIMENTAL EVALUATION OF THE PERFORMANCE OF A VORTEX-DRIVEN AIR LIFT PUMP

A prototype vortex-driven air lift pump was developed and experimentally evaluated. It was designed to be easily manufactured and scalable for arbitrary riser diameters. The model tested fit in a 2 inch diameter riser with six air injection nozzles through which airwas injected helically around the perimeter of the riser at an angle of 70º from pure tangential injection. The pump was intended to transport both water and sediment over a large range of submergence ratios. A test apparatus was designed to be able to simulate deep water or oceanic environments. The resulting test setup had a finite reservoir; over the course of a test, the submergence ratio varied from 0.48 to 0.39. For air injection pressures ranging from 10 to 60 psig and for air flow rates of 6 to 15 scfm, the induced water discharge flow rates varied only slightly, due to the limited range of available submergence ratios. The anticipated simulation of deep water environment, with a corresponding equivalent increase in thesubmergence ratio, proved unattainable. The pump prototype successfully transported both water and sediment (sand). Thepercent volume yield of the sediment was in an acceptable range. The pump design has been subsequently used successfully in a 4 inch configuration in a follow-on project. A computer program was written in Matlab to simulate the pump characteristics. The program output water pressures at the location of air injection which were physicallycompatible with the experimental data.

Fruit yogurt: any erosive potential regarding teeth?

OBJECTIVE: The capability of drinks and foods to resist pH changes brought about by salivary buffering may play an important role in the dental erosion process in children. The aim of the present study was to test fruit yogurt, a popular snack for children, and the degrees of saturation (pK-pl) with respect to hydroxyapatite and fluorapatite to determine their erosive potential. METHOD AND MATERIALS: A variety of fruit yogurt was tested. To test the pH, 8 readings were taken with a pH electrode for each yogurt. Calcium content was detected by atomic absorption spectrophotometer, phosphorus by the inductively coupled plasma method, and fluoride content by ion chromatography. The degrees of saturation of hydroxyapatite and fluorapatite were calculated by use of a computer program. Statistical analysis was performed using 2-tailed analysis of variance (P < .05) and a post hoc test (Tukey) to determine differences between groups. RESULTS: The pH of each fruit concentrate was significantly different, except for banana yogurt. Except for the phosphorus content of raspberry yogurt, the calcium and phosphorus content for each fruit concentrate were significantly different. Fluoride levels were the same for all yogurts tested, and the degrees of saturation of hydroxyapatite and fluorapatite was positive, indicating supersaturation. CONCLUSION: It could be stated that fruit yogurt has no erosive potential.

[Computer-aided surgery of the paranasal sinuses and the anterior skull base]

Endoscopic or microscopic surgery for chronic rhinosinusitis with or without nasal polyps is a routine intervention in daily practice. It is often a delicate and difficult minimally invasive intervention in a narrow space, with a tunnel view of 4 mm in the case of endoscopy and frequent bleeding in chronically inflamed tissue. Therefore, orientation in such a "labyrinth" is often difficult. In the case of polyp recurrence or tumors, the normal anatomical landmarks are often missing, which renders orientation even more difficult. In such cases, computer-aided navigation together with images such as those from computed tomography or magnetic resonance imaging can support the surgeon to make the operation more accurate and, in some cases, faster. Computer-aided surgery also has great potential for education.

Social Networks Analysis

This morning Dr. Risser will introduce you to the basic ideas of social network analysis. You will learn some history behind the study of social networks. Dr. Risser will introduce you to mathematical measures of social networks including centrality measures and measures of spread and cohesion. You will also learn how to use a computer program to analyze social network data

How to Create Posters

This morning Ms. Hayden will introduce you to a computer program designed to help you create a poster for presentation tomorrow.

Reduced frontal activation with increasing 2nd language proficiency

The factors influencing the degree of separation or overlap in the neuronal networks responsible for the processing of first and second language are still subject to investigation. This longitudinal study investigates how increasing second language proficiency influences activation differences during lexico-semantic processing of first and second language. Native English speaking exchange students learning German were examined with functional magnetic resonance imaging while reading words in three different languages at two points in time: at the beginning of their stay (day 1) and 5 months later (day 2), when second language proficiency had significantly increased. On day 1, second language words evoked more frontal activation than words from the mother tongue. These differences were diminished on day 2. We therefore conclude that with increasing second language proficiency, lexico-semantic processing of second language words needs less frontal control. Our results demonstrate that lexico-semantic processing of first and second language converges onto similar networks as second language proficiency increases.

The Topology of Auditory and Visual Perception, Linguistic Communication, and Interactive Written Discourse

In this article, it is shown that IWD incorporates topological perceptual characteristics of both spoken and written language, and it is argued that these characteristics should not be ignored or given up when synchronous textual CMC is technologically developed and upgraded.

Software als Schutzgegenstand des Europäischen Urheberrechts

After 20 years of silence, two recent references from the Czech Republic (Bezpečnostní softwarová asociace, Case C-393/09) and from the English High Court (SAS Institute, Case C-406/10) touch upon several questions that are fundamental for the extent of copyright protection for software under the Computer Program Directive 91/25 (now 2009/24) and the Information Society Directive 2001/29. In Case C-393/09, the European Court of Justice held that “the object of the protection conferred by that directive is the expression in any form of a computer program which permits reproduction in different computer languages, such as the source code and the object code.” As “any form of expression of a computer program must be protected from the moment when its reproduction would engender the reproduction of the computer program itself, thus enabling the computer to perform its task,” a graphical user interface (GUI) is not protected under the Computer Program Directive, as it does “not enable the reproduction of that computer program, but merely constitutes one element of that program by means of which users make use of the features of that program.” While the definition of computer program and the exclusion of GUIs mirror earlier jurisprudence in the Member States and therefore do not come as a surprise, the main significance of Case C-393/09 lies in its interpretation of the Information Society Directive. In confirming that a GUI “can, as a work, be protected by copyright if it is its author’s own intellectual creation,” the ECJ continues the Europeanization of the definition of “work” which began in Infopaq (Case C-5/08). Moreover, the Court elaborated this concept further by excluding expressions from copyright protection which are dictated by their technical function. Even more importantly, the ECJ held that a television broadcasting of a GUI does not constitute a communication to the public, as the individuals cannot have access to the “essential element characterising the interface,” i.e., the interaction with the user. The exclusion of elements dictated by technical functions from copyright protection and the interpretation of the right of communication to the public with reference to the “essential element characterising” the work may be seen as welcome limitations of copyright protection in the interest of a free public domain which were not yet apparent in Infopaq. While Case C-393/09 has given a first definition of the computer program, the pending reference in Case C-406/10 is likely to clarify the scope of protection against nonliteral copying, namely in how far the protection extends beyond the text of the source code to the design of a computer program and where the limits of protection lie as regards the functionality of a program and mere “principles and ideas.” In light of the travaux préparatoires, it is submitted that the ECJ is also likely to grant protection for the design of a computer program, while excluding both the functionality and underlying principles and ideas from protection under the European copyright directives.

Temporal lobe white matter asymmetry and language laterality in epilepsy patients.

Recent studies using diffusion tensor imaging (DTI) have advanced our knowledge of the organization of white matter subserving language function. It remains unclear, however, how DTI may be used to predict accurately a key feature of language organization: its asymmetric representation in one cerebral hemisphere. In this study of epilepsy patients with unambiguous lateralization on Wada testing (19 left and 4 right lateralized subjects; no bilateral subjects), the predictive value of DTI for classifying the dominant hemisphere for language was assessed relative to the existing standard-the intra-carotid Amytal (Wada) procedure. Our specific hypothesis is that language laterality in both unilateral left- and right-hemisphere language dominant subjects may be predicted by hemispheric asymmetry in the relative density of three white matter pathways terminating in the temporal lobe implicated in different aspects of language function: the arcuate (AF), uncinate (UF), and inferior longitudinal fasciculi (ILF). Laterality indices computed from asymmetry of high anisotropy AF pathways, but not the other pathways, classified the majority (19 of 23) of patients using the Wada results as the standard. A logistic regression model incorporating information from DTI of the AF, fMRI activity in Broca's area, and handedness was able to classify 22 of 23 (95.6%) patients correctly according to their Wada score. We conclude that evaluation of highly anisotropic components of the AF alone has significant predictive power for determining language laterality, and that this markedly asymmetric distribution in the dominant hemisphere may reflect enhanced connectivity between frontal and temporal sites to support fluent language processes. Given the small sample reported in this preliminary study, future research should assess this method on a larger group of patients, including subjects with bi-hemispheric dominance.

Models of DNA sequence evolution

Models of DNA sequence evolution and methods for estimating evolutionary distances are needed for studying the rate and pattern of molecular evolution and for inferring the evolutionary relationships of organisms or genes. In this dissertation, several new models and methods are developed.^ The rate variation among nucleotide sites: To obtain unbiased estimates of evolutionary distances, the rate heterogeneity among nucleotide sites of a gene should be considered. Commonly, it is assumed that the substitution rate varies among sites according to a gamma distribution (gamma model) or, more generally, an invariant+gamma model which includes some invariable sites. A maximum likelihood (ML) approach was developed for estimating the shape parameter of the gamma distribution $(\alpha)$ and/or the proportion of invariable sites $(\theta).$ Computer simulation showed that (1) under the gamma model, $\alpha$ can be well estimated from 3 or 4 sequences if the sequence length is long; and (2) the distance estimate is unbiased and robust against violations of the assumptions of the invariant+gamma model.^ However, this ML method requires a huge amount of computational time and is useful only for less than 6 sequences. Therefore, I developed a fast method for estimating $\alpha,$ which is easy to implement and requires no knowledge of tree. A computer program was developed for estimating $\alpha$ and evolutionary distances, which can handle the number of sequences as large as 30.^ Evolutionary distances under the stationary, time-reversible (SR) model: The SR model is a general model of nucleotide substitution, which assumes (i) stationary nucleotide frequencies and (ii) time-reversibility. It can be extended to SRV model which allows rate variation among sites. I developed a method for estimating the distance under the SR or SRV model, as well as the variance-covariance matrix of distances. Computer simulation showed that the SR method is better than a simpler method when the sequence length $L>1,000$ bp and is robust against deviations from time-reversibility. As expected, when the rate varies among sites, the SRV method is much better than the SR method.^ The evolutionary distances under nonstationary nucleotide frequencies: The statistical properties of the paralinear and LogDet distances under nonstationary nucleotide frequencies were studied. First, I developed formulas for correcting the estimation biases of the paralinear and LogDet distances. The performances of these formulas and the formulas for sampling variances were examined by computer simulation. Second, I developed a method for estimating the variance-covariance matrix of the paralinear distance, so that statistical tests of phylogenies can be conducted when the nucleotide frequencies are nonstationary. Third, a new method for testing the molecular clock hypothesis was developed in the nonstationary case. ^

Design and implementation of a multicriteria medical decision support system for diagnosis and treatment

Health care providers face the problem of trying to make decisions with inadequate information and also with an overload of (often contradictory) information. Physicians often choose treatment long before they know which disease is present. Indeed, uncertainty is intrinsic to the practice of medicine. Decision analysis can help physicians structure and work through a medical decision problem, and can provide reassurance that decisions are rational and consistent with the beliefs and preferences of other physicians and patients. ^ The primary purpose of this research project is to develop the theory, methods, techniques and tools necessary for designing and implementing a system to support solving medical decision problems. A case study involving “abdominal pain” serves as a prototype for implementing the system. The research, however, focuses on a generic class of problems and aims at covering theoretical as well as practical aspects of the system developed. ^ The main contributions of this research are: (1) bridging the gap between the statistical approach and the knowledge-based (expert) approach to medical decision making; (2) linking a collection of methods, techniques and tools together to allow for the design of a medical decision support system, based on a framework that involves the Analytic Network Process (ANP), the generalization of the Analytic Hierarchy Process (AHP) to dependence and feedback, for problems involving diagnosis and treatment; (3) enhancing the representation and manipulation of uncertainty in the ANP framework by incorporating group consensus weights; and (4) developing a computer program to assist in the implementation of the system. ^

Beyond sexist beliefs: How do people decide to use gender-inclusive language?

When people use generic masculine language instead of more gender-inclusive forms, they communicate gender stereotypes and sometimes exclusion of women from certain social roles. Past research related gender-inclusive language use to sexist beliefs and attitudes. Given that this aspect of language use may be transparent to users, it is unclear whether people explicitly act on these beliefs when using gender-exclusive language forms or whether these are more implicit, habitual patterns. In two studies with German-speaking participants, we showed that spontaneous use of gender-inclusive personal nouns is guided by explicitly favorable intentions as well as habitual processes involving past use of such language. Further indicating the joint influence of deliberate and habitual processes, Study 2 revealed that language-use intentions are embedded in explicit sexist ideologies. As anticipated in our decision-making model, the effects of sexist beliefs on language emerged through deliberate mechanisms involving attitudes and intentions.

Analysis of participation in the federally mandated coal workers' health surveillance program

The Federal Coal Mine Health and Safety Act of 1969 required that periodic chest radiographs be offered to underground coal miners to protect the miners from the development of Coal Workers' Pneumoconiosis (CWP) and progression of the disease to progressive massive fibrosis (PMF). These examinations are administered by the National Institute for Occupational Safety and Health (NIOSH) through the Coal Workers' Health Surveillance Program (CWHSP). The mine operator is required to provide each miner with the opportunity to have the chest radiograph at no cost to the miner.^ Three rounds of examinations have been conducted since 1969 and the fourth is underway. The decrease in participation over rounds is of great concern if the incidence and progression of CWP are to be understood and controlled.^ This study developed rates of participation for each of 558 West Virginia underground coal mines who submitted or had NIOSH assigned plans for making chest radiographs available during the third round, July 1978 through December 1980. These rates were analyzed in relation to desired levels of participation and to reinforcing, predisposing and enabling factors presumed to affect rates of participation in disease prevention and surveillance programs.^ Two reinforcing factors, size of mine and inclusion of the mine in the National Coal Study (NCS) epidemiology research program, and the enabling factor, use of an on-site radiograph facility, demonstrated highly significant relationships to participation rates.^ The major findings of the study were: (1) Participation in the CWHSP is even lower than previously estimated; (2) CWHSP program evaluation is not systematic and program data base is not complete and comprehensive; and (3) NIOSH program policy is not clear and administration of the CWHSP is fragmented and lacks adequate fiscal and personnel resources. ^

Incidence of breast cancer in first-degree female relatives of men with newly diagnosed prostate cancer

Prostate cancer is the most common incident cancer and the second leading cause of death in men in the United States. Although numerous attempts have been made to identify risk factors associated with prostate cancer, the results have been inconsistent and conflicting. The only established risk factors are age and ethnicity. A positive family history of prostate cancer has also been shown to increase the risk two- to three-fold among close relatives.^ There are several similarities between breast and prostate cancer that make the relationship between the two of interest. (1) Histologically, both cancers are predominantly adenocarcinomas, (2) both organs have a sexual and/or reproductive role, (3) both cancers occur in hormone-responsive tissue, (4) therapy often consists of hormonal manipulation, (5) worldwide distribution patterns of prostate and breast cancer are positively correlated.^ A family history study was conducted to evaluate the aggregation of prostate cancer and co-aggregation of breast cancer in 149 patients referred to The University of Texas, M.D. Anderson Cancer Center with newly diagnosed prostate cancer. All patients were white, less than 75 years of age at diagnosis and permanent residents of the United States. Through a personal interview with the proband, family histories were collected on 1,128 first-degree relatives. Cancer diagnoses were verified through medical records or death certificate. Standardized incidence ratios were calculated using a computer program by Monson incorporating data from Connecticut Tumor Registry.^ In this study, familial aggregation of prostate cancer was verified only among the brothers, not among fathers. Although a statistically significant excess of breast cancer was not found, the increased point estimates in mothers, sisters and daughters are consistent with a co-aggregation hypothesis. Rather surprising was the finding of a seven-fold increased risk of prostate cancer and a three-fold increased risk of breast cancer among siblings in the presence of a maternal history of any cancer. Larger family history studies including high risk (African-Americans) and lower-risk groups (Hispanics) and incorporating molecular genetic evaluations should be conducted to determine if genetic differences play a role in the differential incidence rates across ethnic groups. ^