La classe des graphes de groupes libres à groupes d'arêtes cycliques constitue une source importante d'exemples en théorie géométrique des groupes, en particulier dans le cadre des groupes hyperboliques. Un résultat récent de Wilton montre qu'un tel groupe à un bout et hyperbolique contient un sous-groupe de surface, répondant à une question attribuée à Gromov. Cette thèse est consacrée à l'étude de ces groupes lorsqu'ils se présentent comme des groupes fondamentaux de certains complexes carrés à courbure négative ou nulle. Les complexes carrés en question, appelés graphes tubulaires de graphes, sont obtenus en attachant des tubes (un tube est un produit cartésien d'un cercle avec l'intervalle unitaire) à une collection finie de graphes finis. Le but principal de cette thèse est de construire deux décompositions de base pour les groupes fondamentaux de graphes tubulaires de graphes : leur décomposition de Grushko et leur décomposition JSJ. Dans la première partie de la thèse, nous développons un algorithme en temps polynomial, dont l'entrée est un graphe tubulaire de graphes, et qui produit le scindement de Grushko de son groupe fondamental. Comme application, nous obtenons une version alternative d'un algorithme de Stallings, qui prend un ensemble fini de mots W dans un groupe libre F de rang fini, et décide s'il existe ou non un scindement libre de F relatif à W. Dans la deuxième partie de la thèse, nous développons un algorithme en temps doublement exponentiel, dont l'entrée est un graphe tubulaire de graphes avec un groupe fondamental hyperbolique à un bout, et qui produit le scindement JSJ du groupe fondamental. Nous remarquons qu'il s'agit du premier algorithme sur les scindements JSJ de groupes avec une borne effective sur la complexité de temps. La principale raison de l'efficacité de cet algorithme est que certaines propriétés asymptotiques du groupe, qui déterminent si le groupe se scinde au dessus un sous-groupe cyclique, admettent des caractérisations locales en raison de la structure cubique CAT(0). Comme application de ce résultat, nous obtenons un algorithme en temps doublement exponentiel, dont l'entrée est un groupe libre F de rang fini muni d'un ensemble fini de sous-groupes cycliques W tels que F est librement indécomposable relatif à W, et qui produit le scindement JSJ de F relativement à W. Une conséquence des résultats ci-dessus est que le problème d'isomorphisme pour les groupes considérés se réduit à l'algorithme de Whitehead. / The class of graphs of free groups with cyclic edge groups constitutes an important source of examples in geometric group theory, particularly of hyperbolic groups. A recent result of Wilton shows that any such group which is one-ended and hyperbolic contains a surface subgroup, answering a question attributed to Gromov. This thesis is devoted to the study of these groups when they arise as fundamental groups of certain nonpositively curved square complexes. The square complexes in question, called tubular graphs of graphs, are obtained by attaching tubes (a tube is a Cartesian product of a circle with the unit interval) to a finite collection of finite graphs. The main goal of this thesis is to construct two fundamental decompositions, the Grushko decomposition and the JSJ decomposition, of the fundamental groups of tubular graphs of graphs. In the first part of the thesis we develop an algorithm of polynomial time-complexity that takes a tubular graph of graphs as input and returns the Grushko decomposition of its fundamental group. As an application, we obtain an alternative version of an algorithm of Stallings, which takes a finite set of words W in a finite rank free group F as input, and decides whether or not there exists a free splitting of F relative to W. In the second part of the thesis we develop an algorithm of double exponential time-complexity that takes a tubular graph of graphs with one-ended hyperbolic fundamental group as input and returns the JSJ decomposition of the fundamental group. We remark that this is the first algorithm on JSJ decompositions of groups with an effective bound on the time-complexity. The main reason for the efficiency of this algorithm is that certain asymptotic properties of the group, which determine whether the group splits over a cyclic subgroup, admit local characterisations due to the CAT(0) cubical structure of these groups. As an application of this result, we obtain an algorithm of double exponential time-complexity that takes a finite rank free group F and a finite set of maximal cyclic subgroups W such that F is freely indecomposable relative to W as input and returns the relative JSJ decomposition of F relative to W. A consequence of the above results is that the isomorphism problem for the groups under consideration is reduced to the Whitehead algorithm.

Profound changes in higher education induced by the reforms of the New Public Management (NPM) have led to administrative growth, professionalism, managerialism, and higher relevance of the economic principle. As a further consequence, the importance of the organizational perspective has increased. Thus, questions about effective organizational structures and their design frameworks have become more crucial. The contingency approach provides insights into these questions because it investigates the effectiveness of organizational structures in different situations. Based on expert interviews with faculty managers and subsequent qualitative content analysis, in-depth insights are gained regarding criteria of effectiveness of German faculties, dimensions of their organizational structure, and their contextual factors from their subjective perception. Furthermore, it is possible to renew the approach, to refute criticism, and to build a reference framework as a precursor for developing new theories.

I denna studie har utvecklingen av industriellt underhåll studerats och företaget Quant Services Sweden AB har använts som inspirationskälla. Fallstudien för att testa denna studie har gjorts på Viverk AB.Under min tid som underhållsingenjör på Quant har jag upptäckt utvecklingsmöjligheter för industriellt underhåll, service och eftermarknad. Med stöd av andra studier inom industri 4,0 har jag lyckats få fram vilka teknologier och på vilket sätt man kan nyttja dessa teknologier för att stärka sig själva i den internationella marknaden och även stärka sin konkurrenskraft. En analys har gjorts av Quants nuvarande tillstånd och vilket gap som finns för industri 4,0, och med vilka teknologier man kan fylla detta gap. Jag har även fört diskussioner med andra ingenjörer inom bolaget för att bedöma behovet av ett sådant arbete. Tre fallstudier har utförts för att testa teorin i detta arbete, fallstudierna har utförts på ett annat företag för att påvisa den bredda implementeringen och möjligheterna med andra bolag än det aktuella. Fallstudierna har gjorts på ett företag som heter Viverk AB, som är en tillverkare av industriella tvättmaskiner.3D-printning (additiv tillverkning) är den primära teknologin som studerats vilket även resultatet påvisat. Resultatet av studien visar att underhåll, service och eftermarknad kan implementera ett nytt digitalt verktyg, i Quants fall kan det förslagsvis namnges quant3D för att vara konsekvent utmed Quants andra digitala verktyg.Verktygets syfte är att optimera reservdelsförsörjningen på maskinparken.Detta verktyg kan även stödjas med Digital tvilling (Digital Twins), Artificiell intelligens (Artificial Intelligence), Generativ design (Generative Design) och Sakernas Internet (Internet of Things [IoT]) för att skapa ett komplett Digitalt Verktyg (Digital Toolbox) till sina kunder, vilket resulterar i en bättre reservdelsförsörjning och ständiga förbättringar (Continuous Improvement). Meningen med förbättringsarbetet är att optimera underhållsavdelningen och minimera tiden för oplanerade stopp i produktionen, vilket är underhållets primära mål, det vill säga att syftet är att uppnå högre teknisk tillgänglighet på maskinerna. Fallstudien som har utförts visar även att det finns en vinst i att med hjälp av additiv tillverkning får kortare tid i oplanerade stopp. / In this study, the development of industrial maintenance has been studied andthe company Quant Services Sweden AB has been used as a source of inspiration. The case study to test this study has been done at Viverk AB.During my time as a maintenance engineer at Quant, I have discovered opportunities for industrial maintenance, service, and aftermarket. With the support of other studies in industry 4.0, I have managed to identify which technologies and in what way you can use these and strengthen yourself in the international market and strengthen your competitiveness.An analysis has been made of Quant's current state and what gap there is for industry 4.0, and with what technologies one can fill this gap. I have also had discussions with other engineers within the company to assess the need for such work. Three case studies have been carried out to test the theory in this work, the case studies have been carried out at another company to demonstrate the wide implementation and the possibilities with other companies than the current one. The case studies have been done at a company called Viverk AB, which is a manufacturer of industrial washing machines.3D printing (additive manufacturing) is the primary technology studied, the results of which have also been demonstrated. The result of the study shows that maintenance, service, and aftermarket can implement a new digital tool, in Quant's case it can be named quant3D to be consistent with Quant's other digital tools. The purpose of the tool is to optimize the supply of spare parts on the machine parkThis tool can also be supported with Digital Twins, Artificial Intelligence, Generative Design and the Internet of Things (IoT) to create a complete Digital Toolbox for their customers, resulting in a better supply of spare parts and continuous improvement (CI).The purpose of the improvement work is to optimize the maintenance department and minimize the time for unplanned stops in production, which is the primary goal of maintenance, that is the purpose to achieve higher technical availability on the machines. The case study that has been carried out also shows that there is a profit in using additive manufacturing to reduce the time in unplanned stops.

Trotz der zahlreichen astrophysikalisch und kosmologisch überzeugenden Beweise für Dunkle Materie bleibt ihre wahre Natur unbekannt. Eine Motivation für die Suche nach Dunkler Materie am Large Hadron Collider (LHC) und insbesondere mit dem ATLAS-Experiment ist die besonders vielversprechende Möglichkeit, dass Wechselwirkungen zwischen gewöhnlicher Materie und Dunkler Materie durch neue Spin-0-Teilchen vermittelt werden. Solche Teilchen würden das Standardmodell um einen potentiellen Dunklen Sektor erweitern, zu dem die Teilchen der Dunklen Materie gehören. ähnlich wie das Higgs-Boson interagieren diese neuen Mediatoren am stärksten mit den schwersten Teilchen über Kopplungen vom Yukawa-Typ, wodurch sie empfänglicher für die damit verbundene Produktion durch Quarks mit schwerem Flavour werden. Diese Dissertation präsentiert die Ergebnisse der statistischen Kombination von zwei Suchen, die auf die mit Dunkler Materie verbundene Produktion von einem Top-Quark-Paar oder einem einzelnen Top-Quark, jeweils zwei geladenen Leptonen im Endzustand, abzielen. Diese beiden Kanäle weisen komplementäre Eigenschaften auf, und eine Kombination kann die Empfindlichkeit gegenüber Dunkle-Materie-Signalen erheblich verbessern. Diese Kombination wird unter Verwendung von 139 fb-1 pp-Kollisionsdaten durchgeführt, die bei einer Schwerpunktsenergie von 13 TeV erzeugt und vom ATLAS-Detektor am LHC aufgezeichnet wurden. Die Ergebnisse der Kombination werden in Bezug auf vereinfachte Modelle für Dunklen Materie mit einem skalaren oder pseudoskalaren Spin-0-Mediator interpretiert. Die statistische Kombination weitet die bei einem Konfidenzniveau von 95% ausgeschlossenen Massen auf bis zu 350 GeV sowohl für skalare als auch für pseudoskalare Mediatoren aus. Die beobachteten Ausschlu{\ss}grenzen des Wirkungsquerschnitts werden für den ska\-laren (pseudoskalaren) Mediator um 20%(30%) gegenüber dem Besten des einzelnen Kanals verbessert. / Despite the multiple astrophysical and cosmological compelling evidences for Dark Matter, its true nature remains unknown. A motivation to dark matter searches at the Large Hadron Collider (LHC), and in particular in the ATLAS experiment, is the especially promising possibility that interactions between ordinary matter and dark matter are mediated by new spin-0 particles. Such particles would extend the Standard Model with a potential dark sector, to which dark matter particles belong. Similarly to the Higgs boson, these new mediators interact strongest with the heaviest particles via Yukawa-type couplings, making them more prone to associated production with heavy-flavour quarks. This thesis presents the results of the statistical combination of two searches targeting dark matter associated production with a top quark pair and a single top quark, targeting two charged leptons in the final state. These two channels present in fact complementary properties and a combination could enhance significantly the sensitivity to dark matter signals. This combination is carried out using 139 fb-1 of pp collision data produced at centre-of-mass of 13 TeV recorded by the ATLAS detector at the LHC. The results of the combination are interpreted in terms of simplified dark matter models with a spin-0 scalar or pseudoscalar mediator particle. The statistical combination extends the exclusion at 95 % Confidence Level (CL) of masses up to 350 GeV for both scalar and pseudoscalar mediators. The observed upper limits on the cross-section are improved up by 20 %(30 %) for scalar(pseudoscalar) mediator with respect to the best of the individual channel.

Background: Circulating long-chain (LCSFAs) and very long-chain saturated fatty acids (VLSFAs) have been differentially linked to risk of incident heart failure (HF). In patients with heart failure with preserved ejection fraction (HFpEF), associations of blood SFA levels with patient characteristics are unknown. Methods: From the Aldo-DHF-RCT, whole blood SFAs were analyzed at baseline in n = 404 using the HS-Omega-3-Index methodology. Patient characteristics were 67 8 years, 53% female, NYHA II/III (87%/13%), ejection fraction 50%, E/e’ 7.1 1.5; and median NT-proBNP 158 ng/L (IQR 82–298). Spearman´s correlation coefficients and linear regression analyses, using sex and age as covariates, were used to describe associations of blood SFAs with metabolic phenotype, functional capacity, cardiac function, and neurohumoral activation at baseline and after 12-month follow-up (12 mFU). Results: In line with prior data supporting a potential role of de novo lipogenesis-related LCSFAs in the development of HF, we showed that baseline blood levels of C14:0 and C16:0 were associated with cardiovascular risk factors and/or lower exercise capacity in patients with HFpEF at baseline/12 mFU. Contrarily, the three major circulating VLSFAs, lignoceric acid (C24:0), behenic acid (C22:0), and arachidic acid (C20:0), as well as the LCSFA C18:0, were broadly associated with a lower risk phenotype, particularly a lower risk lipid profile. No associations were found between cardiac function and blood SFAs. Conclusions: Blood SFAs were differentially linked to biomarkers and anthropometric markers indicative of a higher- /lower-risk cardiometabolic phenotype in HFpEF patients. Blood SFA warrant further investigation as prognostic markers in HFpEF. One Sentence Summary: In patients with HFpEF, individual circulating blood SFAs were differentially associated with cardiometabolic phenotype and aerobic capacity.

Text in Afrikaans / Summaries in English and Afrikaans / In die veertigerjare het Robert Gordis aanhalings in die boek Prediker uitgewys. Diethelm Michel en Norman Whybray het die aanhalingshipotese ondersteun, terwyl Michael Fox nie ten gunste daarvan was nie. Whybray het kriteria saarngestel op grond waarvan hy aanhalings uit ouer wysheidsmateriaal kon onderskei. Fox kon op grond van sy eie kriteria geen aanhalings identifiseer nie. Om vas te st el of die Prediker we! uit ouer wysheidsmateriaal aanhaal, word eerstens gekyk na hoe die wysheid in Israel ontstaan het en wat die boek Prediker se verhouding tot ander wysheidsgeskrifte is. Hie ma word die histories-kritiese bestudering van die boek onder die loep geneem alvorens die navorsingsgeskiedenis van aanhalings nagegaan word. Prediker 9-11 word ondersoek om te bepaal of die Prediker we! uit vroeere wysheidsmateriaal aanhaal. Ten slotte word die vraag gevra of Bybelvertalings aanhalings moet uitlig ten einde die teks beter verstaanbaar te maak. / In the forties, Robert Gordis pointed out that quotations do occur in the book Ecclesiastes. Diethelm Michel and Norman Whybray endorsed this hypothesis of quotations, while Michael Fox has taken a stance against it. Whybray compiled criteria to distinguish older wisdom sayings in the book Ecclesiastes. Fox applied his own criteria and could not find any quotations. To determine if the author (Qohelet) does quote from older wisdom material, we take a look how the wisdom developed in Israel and what the book's relation was to other wisdom books. Then the contribution of the historical-critical methods to the understanding of the book is surveyed before die research history of quotations is discussed. Ecclesiastes 9-11 is examined to determine if Qohelet really quotes from older wisdom material. Finally, we ask the question whether quotations should be highlighted in Bible translations in order to improve understanding of the text. / Biblical and Ancient studies / M.A.(Biblical Studies)

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Aerospace Report No. TOR-0059(6110-01)-3, section 1.3.3 outlines the design and performance requirements of SGLS (Space Ground Link Subsystem) services. GDP Space Systems has developed a single card slot FSK (Frequency Shift Keying)/AM (Amplitude Modulation) demodulator. An application of this service is the US Air Force Satellite Command and Ranging System. The SGLS signal is tri-tone-FSK, amplitude modulated by a modified triangle wave at half the data rate. First generation FSK/AM demodulators had poor noise performance because the signal tones were filtered and processed at IF frequencies (65, 76 and 95 kHz). Second generation demodulators suffer from "threshold" due to non-linear devices in the signal path before the primary noise filtering. The GDP Space Systems demodulator uses a 0-Hz- IF topology and avoids both of these shortcomings. In this approach, the signal is first noncoherently down converted to baseband by linear devices, then it is filtered and processed. This paper will discuss the GDP 0-Hz-IF FSK/AM (SGLS) demodulator.

The dissertation describes Pd0-catalyzed formal 1,3-diaza-Claisen rearrangement and the design and development of cationic 1,3-diaza-Claisen rearrangement. Our previous work has shown that isocyanates react with azanorbornenes and azabicyclo[2.2.2]octenes under thermal conditions to afford zwitterionic intermediates that undergo a thermal 1,3-diaza-Claisen rearrangement to give both ureas and isoureas. However, some azanorbornenes and azabicyclooctenes failed to rearrange or proceeded in low yields. To address these challenging substrates for the thermal 1,3-diaza-Claisen rearrangement, we have developed a Pd0-catalyzed formal 1,3-diaza-Claisen rearrangement. Interestingly, under Pd0-catalyzed condition, both isocyanates with electron-withdrawing groups and isocyanates without electron-withdrawing groups react with azanorbornenes and azabicyclo[2.2.2]octenes to provide ureas as the only products in high yields. More importantly, the reactions that failed under thermal conditions were all successful under Pd0-catalysis. In addition to azanorbornenes and azabicyclo[2.2.2]octenes, other ring systems were also investigated. Pd0 catalysis has broadened the scope of tertiary allylic amines that react with isocyanates to afford 1,3-diaza-Claisen rearrangement products. In the presence of p-TsCl and NEt3, allylaminopropyl benzyl ureas were initially dehydrated to form protonated carbodiimides whose presence was confirmed by the infrared absorption frequency at 2100 cm-1 which is the characteristic band of -N=C=N-; then the in situ generated protonated carbodiimides were poised for further cationic 1,3-diaza-Claisen rearrangement to afford synthetically challenging guanidines. The effect of acid on the rearrangement was ascertained by the fact that no rearrangement product was observed by simply heating free base carbodiimide 3.10 in benzene at reflux. Other dehydration reagents, such as Tf2O, Ts2O, MsCl were also investigated, and none of them provide satisfactory results. A selection of allyamino benzyl ureas with different tether length, substituents, or in varied ring systems, were synthesized to explore the scope of this methodology. This methodology works best at allylaminopropyl benzyl ureas, and the substituents on the benzyl group does not seem to affect the reaction rate in a significant way.

In den vergangenen Jahren wurde vermehrt das Gen, welches für Catechol-O-Methyltransferase codiert, als starker Kandidat für ein erhöhtes Schizophrenierisiko diskutiert. Grund dafür ist die zentrale Rolle der Catechol-O-Methyltransferase beim Katecholaminabbau im menschlichen präfrontalen Cortex. Aufgrund der zunehmend akzeptierten Tatsache, daß die singuläre Betrachtung einzelner Marker bei der komplexen genetischen Textur von Kandidatengenen nur wenig zur Erhellung komplexer Erkrankungen beizutragen vermag (Licinio, 2003), untersuchten wir neben dem Val108/158Met-Polymorphismus (rs4680) vier weitere, die COMT-Gen-Region umspannende SNPs (rs2097603, rs740603, rs4818, rs165599) an einer Stichprobe von 459 Schizophrenen und 150 Kontrollpersonen. Zwar ergab sich für den Marker rs740603 auf Intron 1 eine signifikante Allel- (p = 0.0060) und Genotypassoziation (p = 0.019), der funktionelle Val108/158Met-Polymorphismus (rs4680) zeigte aber keinen signifikanten Zusammenhang mit der Erkrankung. Zudem fand sich in unserer Haplotypanalyse keine Markerkombination, die in überdurchschnittlichem Zusammenhang mit schizophrenen Psychosen stand. Für die Untergruppe der zykloiden Psychosen ließ sich bei einem p-Wert von 0.031 eine 4-Marker-Kombination ermitteln, die die SNPs rs740603, rs4818, rs4680 und rs165599 einschliesst und die Region von Intron 1 bis 3´-UTR umspannt. Zusätzlich ergab sich in der Subgruppe der zykloiden Psychosen ein geschlechtsspezifischer Effekt im Sinne eines signifikanten 3-Marker-Haplotypen (rs4818-rs4680-rs165599) (p = .0044) in der Gruppe der Frauen (n = 27) mit rs165599 als stärkstem Einzelmarker. Aufgrund des komplexen genetischen Zusammenhangs zwischen den untersuchten Markern und der Erkrankung sollte auch in der zukünftigen Forschung eine differenzierte Betrachtung der verschiedenen schizophrenen Zustandsbilder angestrebt werden, wie dies die Klassifikation nach Leonhard ermöglicht. Neben gewebsspezifischen Transkriptionsfaktoren könnten auch epigenetische Faktoren, wie die Cytosinmethylierung von CpG-Stellen in promotorregulierenden Regionen, einen Erklärungsansatz für die Entstehung schizophrener Störungsbilder darstellen. / Since several years, the gene encoding catechol-O-methyltransferase (COMT) at chromosome 22q11 is discussed as a strong candidate for schizophrenia susceptibility due to its key function in degredation of catecholamines in the prefrontal cortex, a critical region of the human brain, involved in cognitive control processes, monitoring of information in working memory and in active judgments on information (Petrides, 2005). To test the association of the COMT gene locus with schizophrenia, we analysed five SNPs (rs2097603, rs740603, rs4818, rs4680, rs165599) spanning from the P2 promotor region (MB-COMT) to the 3´-UTR in 459 index cases, which fulfilled diagnistic criteria of schizophrenia according to DSM IV as well as 150 blood donors as population controls. According to differentiated psychopathology (Leonhard, 1999) probands were categorized into cycloid psychosis, unsystematic schizophrenia and systematic schizophrenia prior to genotyping. In intron 1 the marker rs740603 showed significant allele (p = 0.0060) and genotype (p = 0.019) association, but the functional Val105/158Met variant (rs4680) failed significant association with disease. Considering COMT haplotypes none of the marker combinations showed evidence for an association with schizophrenia. In the subgroup of cycloid psychosis we found 4-locus marker combinations rs740603-rs4818-rs4680-rs165599 associated with disease at p-level 0.031, spanning a region from intron 1 to the 3´-UTR. In conclusion, the genetic interaction of COMT SNPs and haplotypes and schizophrenia susceptibility appears complex across different populations and psychopathological phenotypes. Particularly structures potentially involved in mRNA expression levels need further scrutiny.

Hintergrund: Das visuelle Arbeitsgedächtnis ist eine Leistung des präfrontalen Kortex (PFC) und dient der kurzfristigen Speicherung und Manipulation visueller Information. Ein aufgabenspezifisches Modell des visuellen Arbeitsgedächtnisses unterteilt zwei inhaltlich und örtlich getrennte Subsysteme: Das visuell-räumliche Arbeitsgedächtnis (SWM) scheint vor allem im dorsolateralen PFC (DLPFC) und das visuell-bildliche (OWM) im ventrolateralen PFC (VLPFC) lokalisiert zu sein. Der Dopaminabbau im PFC wird entscheidend von dem Enzym Catechol-O-Methyltransferase (COMT) bestimmt. Es existiert ein funktioneller COMT-Val158Met-Polymorphismus, der aufgrund veränderter Enzymaktivität mit unterschiedlicher dopaminerger Aktivität im PFC verbunden ist. Ziele: Das Aufgabendesign zielte darauf ab, die funktionelle Trennung von SWM und OWM im PFC nachzuweisen und die aufgabenspezifische Hypothese zu testen. Als zweites Ziel der Studie sollte der mögliche Einfluss des COMT-Val158Met-Polymorphismus auf die Arbeitsgedächtnisleistung getestet werden. Methoden: Es wurden 100 körperlich und psychisch gesunde Probanden in einer funktionellen Nah-Infrarot Spektroskopie-Studie (fNIRS-Studie) mit einem visuellen Arbeitsgedächtnisparadigma untersucht. Die NIRS-Messung beruht auf dem Prinzip der neurovaskulären Kopplung. Es wurde eine rechteckige 30*6 cm große Messhaube über dem frontalen Kortex platziert und die Veränderungen von O2Hb und HHb während des Paradigmas bestimmt. Anschließend wurde eine Genotypisierung durchgeführt. Ergebnisse und Diskussion: Zwischen den Arbeitsgedächtnisaufgaben zeigte sich ein deutlicher linearer Zusammenhang für die Verhaltensdaten. Das SWM-Paradigma führte zu einem O2Hb-Anstieg und HHb-Abfall im DLPFC, womit sich eine selektive Aktivierung dieses Areals bestätigte. OWM-Aufgaben hingegen führten zu einem parallelen Anstieg von O2Hb und HHb im VLPFC. Mit der fNIRS-Untersuchung konnten Vorbefunde der funktionellen Bildgebung bestätigt werden, die eine aufgabenspezifische Gliederung des visuellen Arbeitsgedächtnisses postulieren. Ein funktioneller Zusammenhang zwischen dem COMT-Val158Met-Polymorphismus und dem Arbeitsgedächtnis konnte weder in den Verhaltensdaten noch in den Bildgebungsdaten nachgewiesen werden. Falls ein solcher Zusammenhang besteht, lag der fehlende Nachweis am ehesten in Task-Switching-Effekten des Studiendesigns begründet. / Objective: Visual working memory is an accomplishment of the prefrontal cortex (PFC), which serves the maintenance and manipulation of visual information over a short period of time. A ‘domain-specific’ model of visual working memory divides it into two functionally and spatially separated subsystems: Visual location-based memory (SWM) seems to be located in the dorsolateral PFC (DLPFC), visual objective-based memory (OWM) to be located in the ventrolateral PFC (VLPFC). The turnover of dopamine is critically tuned by the enzyme catechol-o-methyl-transferasis (COMT). There is a functional COMT-Val158Met-polymorphism which is associated with different dopaminergic levels in PFC due to a change in enzyme-activity. Aim: The task design was conceived to evaluate the functional dissociation of SWM and OWM in the PFC and to test the ‘dopamin-specific’ hypothesis. Secondly the study aims at testing the possible contribution of COMT-Val158Met-polymorphism to working memory. Methods: Therefore 100 somatically and mentally healthy subjects were assessed by an event-related functional near-infrared-study (fNIRS) with a visual working memory paradigm. The NIRS relies on the principle of neurovascular coupling. A 30*6 cm rectangle probeset was applied on the frontal cortex and changes in O2Hb and HHb were measured during the paradigms. After that, genotyping of the COMT-polymorphism was conformed. Results and Discussion: There was a significant linear dependence of working memory task in regard of behavioral data. SWM paradigm was accompanied by some increase in O2Hb and parallel decrease of HHb in the DLPFC which is in line with a selective activity of this area in SWM. OWM paradigm led to a parallel increase of O2Hb and HHb in the VLPFC. With the NIRS technique it was possible to replicate prior findings of functional imaging studies which postulated a ‘domain specific’ organization of the visual working memory. It was not possible however, to determine any connection between the COMT-Val158Met-polymorphism and the working memory in behavioral or functional imaging data. If there is such an interaction, the missing proof might be due to task-switching-effects in the design of the study.