Optimal Rules for Patent Races

There are two important rules in a patent race: what an innovator must accomplish to receive the patent and the allocation of the benefits that flow from the innovation. Most patent races end before R&D is completed and the prize to the innovator is often less than the social benefit of the innovation. We study the optimal combination of prize and minimal accomplishment necessary to obtain a patent in a dynamic multistage innovation race. A planner, who cannot distinguish between competing firms, chooses the innovation stage at which the patent is awarded and the magnitude of the prize to the winner. We examine both social surplus and consumer surplus maximizing patent race rules. We show that a key consideration is the efficiency costs of transfers and of monopoly power to the patentholder. We show that races are undesirable only when efficiency costs are low, firms have similar technologies, and the planner maximizes social surplus. However, in all other circumstances, the optimal policy spurs innovative effort through a race of nontrivial duration. Races are also used to filter out inferior innovators.

Molecular and behavioral analysis of magneto-aerotaxis in Magnetospirillum gryphiswaldense

Magnetotactic bacteria (MTB) contain nanometer-sized crystals of a magnetic iron mineral enabling directed swimming along geomagnetic field lines. However, although this unique behavior was discovered already 40 years ago, it still has remained poorly understood at the cellular level and the molecular mechanisms responsible for sensing environmental stimuli and transducing signals to the flagellar motors have been unknown. Therefore, the major goal of this thesis was to investigate the swimming behavior of Magnetospirillum gryphiswaldense both at the behavioral and molecular level. Individual motors of tethered M. gryphiswaldense cells were found to rotate both clockwise and counterclockwise with equal speed. Cells swam at speeds of up to 60 µm s-1 and commonly displayed runs of several hundred µm in length. In striking contrast to E. coli, which reorients the cell body between run intervals at random angles, motor switching events caused swimming reversals with reorientation angles close to 180°. The sensory repertoire of M. gryphiswaldense was analyzed by classical macroscopic chemotaxis assays, and aerotaxis was found to be the dominant behavior. In addition to the strong microaerophilic response in oxygen gradients, I observed tactic bands also under anoxic conditions within gradients of the alternative electron acceptor nitrate, suggesting that aerotaxis is part of a general redox or energy taxis mechanism. The aerotactic response of M. gryphiswaldense was furthermore analyzed by recording and tracking single cells under controlled atmospheric conditions in a gas perfusion chamber. Compared to other well-studied bacteria, M. gryphiswaldense displayed unusually low swimming reversal rates (<0.1 s-1) under equilibrium conditions. Abruptly shifting oxygen levels from 2% to 0% only slightly increased reversal rates, whereas a reverse shift from 0% to 2% caused a transient threefold increase in reversal rates that was directly followed by an extraordinarily sustained smooth-swimming phase without return to pre-stimulus levels. Apart from 56 putative genes encoding chemoreceptors that might be involved in magnetotaxis, four putative chemotaxis operons (cheOp1-4) were identified in the genome of M. gryphiswaldense, containing genes commonly involved in signal transduction from chemoreceptors to the flagellar motors. Single or combined deletions of cheOp2-4 did not have any pronounced effect on motility or aerotaxis. In striking contrast, deletion of cheOp1, which comprises only the canonical set of chemotaxis genes (cheAWYBR), caused individual cells to swim straight without reversing, resulting in a complete loss of aerotaxis. When analyzed under oxic conditions, most MTB possess a clear directional preference corresponding to downward movement in their natural habitat, referred to as “polar magneto-aerotaxis”. Although cultivated strains of magnetotactic spirilla were previously assumed to lack any directional preference, in this work polar swimming behavior could be restored in M. gryphiswaldense through repeated cultivation of cells in magnetic fields superimposed on oxygen gradients. Individual cells displayed a gradual bias of swimming runs with one of the cell poles leading that depended on ambient oxygen levels. In anoxic microdroplets, addition of 2% oxygen rapidly reversed the overall swimming direction of the entire population. However, in the absence of CheOp1 swimming polarity could be no longer selected and no reversal of swimming bias was observed. These findings for the first time show that there is a direct molecular link between aerotactic sensing and the determination of magnetotactic polarity, through the sensory pathway CheOp1. In a joint project in the last part of this thesis, I demonstrated how magnetotactic behavior can be manipulated through artificial recruitment of polarly localized CheW1-GFP fusion proteins to midcell anchors. GFP-labelled proteins were trapped by expressing GFP-binding nanobodies on the magnetosome membrane surface (referred to as “nanotrap”). By varying the expression level of the nanobody, a gradual knockdown of magneto-aerotaxis was achieved.Magnetotaktische Bakterien (MTB) enthalten wenige Nanometer große Kristalle magnetischer Eisenminerale, die ihnen die faszinierende Fähigkeit verleihen, sich entlang der Feldlinien des Erdmagnetfelds fortzubewegen. Obwohl diese besondere Form bakteriellen Schwimmverhaltens bereits vor nunmehr 4 Jahrzenten entdeckt wurde, ist das Verhalten einzelner Zellen, sowie die Mechanismen, die der Reizerkennung und Signaltransduktion zum Flagellenmotor zugrunde liegen, bis heute nur wenig erforscht. Das Ziel dieser Doktorarbeit war daher, die molekularen Grundlagen der Magnetotaxis im Modellorganismus Magnetospirillum gryphiswaldense zu charakterisieren und die Motilität einzelner Zellen detailliert zu untersuchen. Im ersten Teil meiner Arbeit konnte ich zeigen, dass die Flagellenmotoren von M. gryphiswaldense jeweils mit gleicher Geschwindigkeit in beide Drehrichtungen rotieren und dadurch die Zellen auf bis zu 60 µm s-1 beschleunigen. Im Gegensatz zu E. coli, das während häufiger Taumelphasen seine Ausrichtung ändert, werden die oft mehrere hundert Mikrometer langen, geraden Schwimmepisoden von M. gryphiswaldense durch Umkehrvorgänge unterbrochen, die eine Änderung der Schwimmrichtung um ca. 180° bewirken. Bei der Untersuchung des allgemeinen chemotaktischen Verhaltens in makroskopischen Tests zeigte sich, dass die mikroaerophile Antwort von M. gryphiswaldense stark dominiert. Da unter Ausschluss von Sauerstoff zudem Bandenbildung in künstlich hergestellten Nitratgradienten beobachtet wurde, kann davon ausgegangen werden, dass das dominante aerotaktische Verhalten Teil einer umfassenderen Redox- oder Energietaxis ist. Die Aerotaxis von M. gryphiswaldense wurde anschließend unter kontrollierten atmosphärischen Bedingungen auf Einzelzellebene untersucht. Im Vergleich zu anderen gut erforschten Bakterien wurden unter Gleichgewichtsbedingungen nur relativ wenige Umkehrvorgänge registriert (<0.1 s-1), und ein abruptes Absenken des Sauerstoffgehalts von 2% auf 0% führte zu einer lediglich geringen Zunahme der Umkehrvorgänge. Nach einer plötzlichen Anhebung des Sauerstoffgehalts von 0% auf 2% stieg dagegen die Umkehrfrequenz kurzzeitig um das Dreifache an. Im Anschluss hieran wurden jedoch bemerkenswerterweise über lange Zeiträume fast keine Umkehrvorgänge registriert und selbst nach 80 s lag die Umkehrfrequenz unter dem Ausgangswert. In der genomischen Sequenz von M. gryphiswaldense wurden neben 56 Chemorezeptor-Genen insbesondere vier mutmaßliche Chemotaxisoperons (cheOp1-4) identifiziert. Während die Deletion von cheOp2-4(sowohl einzeln als auch in Kombination)keinen deutlichen Einfluss auf das Schwimmverhalten hatte, wurde nach Deletion von cheOp1 ein komplett nicht-aerotaktischer Phänotyp beobachtet, gekennzeichnet durch lange, ununterbrochene Schwimmepisoden. Unter sauerstoffgesättigten Bedingungen weisen die meisten MTB eine klare Richtungspräferenz auf, sogenanntes „polares Schwimmverhalten“. Obwohl den in Reinkultur verfügbaren Magnetospirillen diese Fähigkeit traditionell abgesprochen wurde, konnte im Rahmen der vorliegenden Arbeit durch wiederholte Kultivierung von M. gryphiswaldense in Sauerstoffgradienten, die von Magnetfeldern überlagert waren, polares Verhalten erzeugt werden. Die Mehrzahl der Zellen wies eine graduelle Bevorzugung einer Schwimmrichtung auf, die sich durch Variation des Sauerstoffgehalts beeinflussen ließ. Dies wurde durch Beobachtungen an zunächst anaerobisierten Zellpopulationen untermauert, die bei Zuführung von 2% Sauerstoff kollektiv ihre Vorzugsschwimmrichtung änderten. Nach Deletion von cheOp1 wurde im Gegensatz dazu keine Wiederherstellung der Schwimmpolarität beobachtet, was den Schluss nahe legt, dass ein direkter Zusammenhang zwischen der durch cheOp1 kodierten Signaltransduktionskaskade und der molekularen Determination der magnetotaktischen Polarität existiert. Im letzten Abschnitt dieser Arbeit konnte ich im Rahmen eines Kooperationsprojekt zeigen, wie durch Expression von GFP-bindenden nanobodies auf der Magnetosomenoberfläche die native Lokalisierung von GFP-markierten Signaltransduktionskomponenten künstlich verändert wird. Durch Variation der Kopienzahl des nanobodies wurde das CheW1-GFP Fusionsprotein in unterschiedlichem Umfang zur Zellmitte verschoben, was einen graduellen Ausfall der Magneto-Aerotaxis bewirkte

A Cognitive Architecture Based on a Learning Classifier System with Spiking Classifiers

© 2015, Springer Science+Business Media New York. Learning classifier systems (LCS) are population-based reinforcement learners that were originally designed to model various cognitive phenomena. This paper presents an explicitly cognitive LCS by using spiking neural networks as classifiers, providing each classifier with a measure of temporal dynamism. We employ a constructivist model of growth of both neurons and synaptic connections, which permits a genetic algorithm to automatically evolve sufficiently-complex neural structures. The spiking classifiers are coupled with a temporally-sensitive reinforcement learning algorithm, which allows the system to perform temporal state decomposition by appropriately rewarding “macro-actions”, created by chaining together multiple atomic actions. The combination of temporal reinforcement learning and neural information processing is shown to outperform benchmark neural classifier systems, and successfully solve a robotic navigation task

Exploring How Aspiring Clinical Psychologists from Different Racial Groups Experience and Make Sense of their NHS Career Trajectory

Racial diversity in the clinical psychology workforce has increased in recent years. However, the profession is situated within a broader National Health Service (NHS) context where there is evidence of workforce racial inequity in staff recruitment, career development, and progression. Previous studies have focused on the experiences of trainee and qualified clinical psychologists from underrepresented racial backgrounds, and there exists little research on the experience of those racialised as White. Therefore, in this study I aimed to gain an insight into the lived experiences of aspiring clinical psychologists (ACPs) from different racial backgrounds working in the NHS, and how they made sense of their pre-qualification career trajectory. I conducted two racially homogenous online focus groups with Black British (n=5) and White British (n=5) ACPs with at least 6 months’ experience of working in NHS mental health services. I transcribed and analysed the focus groups using interpretative phenomenological analysis. My analysis yielded three whole-group themes. ACPs experienced and made sense of their pre-qualification career trajectories in relation to 1) the profession, 2) interpersonal relationships, and 3) sense of self. Stark differences emerged across racial groups, highlighting how ACPs experiences within the NHS are shaped by power in relation to race, institutional racism, and Whiteness. White British ACP group experiential themes (GETs) included ‘Whiteness as the norm in clinical psychology’, ‘I feel confident and supported’, and ‘Luck vs. Merit’. Black British ACPs GETs included ‘Being Black: An asset vs. Racism’, ‘Support: A luxury vs. A right’, and ‘Racism costs me energy’. I explored these findings in relation to existing literature, as well as the implications for policy and practice within clinical psychology

Exploring the Modularity and Structure of Robots Evolved in Multiple Environments

Traditional techniques for the design of robots require human engineers to plan every aspect of the system, from body to controller. In contrast, the field of evolu- tionary robotics uses evolutionary algorithms to create optimized morphologies and neural controllers with minimal human intervention. In order to expand the capability of an evolved agent, it must be exposed to a variety of conditions and environments. This thesis investigates the design and benefits of virtual robots which can reflect the structure and modularity in the world around them. I show that when a robot’s morphology and controller enable it to perceive each environment as a collection of independent components, rather than a monolithic entity, evolution only needs to optimize on a subset of environments in order to maintain performance in the overall larger environmental space. I explore previously unused methods in evolutionary robotics to aid in the evolution of modularity, including using morphological and neurological cost. I utilize a tree morphology which makes my results generalizable to other mor- phologies while also allowing in depth theoretical analysis about the properties rel- evant to modularity in embodied agents. In order to better frame the question of modularity in an embodied context, I provide novel definitions of morphological and neurological modularity as well as create the sub-goal interference metric which mea- sures how much independence a robot exhibits with regards to environmental stimu- lus. My work extends beyond evolutionary robotics and can be applied to the opti- mization of embodied systems in general as well as provides insight into the evolution of form in biological organisms

Sourcing of low-tech omponents in high-tech environments

Problemställning: Low tech-komponenter anses enligt teoretiska rekommendationer ofta som icke kritiska. Dock har de egenskaper som en gång ansågs synnerligen low tech förmodligen förändrats och blivit mer komplexa i takt med att underliggande krav inom high tech-miljöer har ökat. Det är befogat att diskutera och kanske omdefiniera de eventuellt senare omprioriterade komponenterna, vilka i aggregerad form representerar en produkt på systemnivå. Hur borde processen för den eventuella omprioriteringen genomföras och vilka krav kommer att påverka företaget? Den ökade komplexiteten kring produktegenskaperna kan också innebära att leverantörer försöker bli unika, vilket implicit påverkar Sony Ericsson. Det vore därför synnerligen intressant att fastställa hur Sony Ericsson borde förhålla sig till leverantörsimplementerade strategier för low tech-komponenter samt hur sourcing som en funktion i ett high tech-bolag borde reagera till dessa förändrade förutsättningar och skiftade affärskontext. Syfte: Syftet med detta examensarbete är att ge förslag på hur sourcing av low-tech-komponenter kan förbättras för företag i dynamiska high-tech-miljöer. Metod: En case study-ansats har tillämpats för att möjliggöra undersökningen enligt det fastställda syftet. Metoden har anpassats för att kunna erhålla en undersökning på såväl komponent- som leverantörsnivå. Det valda case-företaget är Sony Ericsson då det verkar i en utpräglad high tech-kontext och strävar efter best practice inom sourcing. Både kvalitativa och kvantitativa undersökningsmetoder har använts för att säkerställa validitet och reliabilitet. Kvalitativa intervjuer hölls med flertalet anställda på Sony Ericsson inom olika divisioner för att skapa förståelse för komplexiteten i frågeställningen. Slutsatser: Portföljmodeller för inköp används i stor utsträckning och ses ofta som ett centralt verktyg för förbättrande av inköp eftersom effektivt differentierade inköps- och leverantörsstrategier kan implementeras. Dock är teoretiska komponentklassificeringar vanskliga då mycket har hänt sedan vedertagna modeller togs fram, i synnerhet inom high tech-miljöer. Till viss del är high tech-komponenter, såsom skruvar, på grund av sin produktutveckling och sina mer komplexa egenskaper felaktigt definierade. Vid förlitning på vedertagna teoretiska klassificeringar kan implementerade inköpsstrategier få förödande sourcing-konsekvenser. Vi hävdar att vissa sourcing-komponenter trots att de är teoretiskt klassificerade som icke kritiska de facto kan vara kritiska på en systemnivå och därför har stor vinstinverkan på företag. COMPASS-ramverket har framtagits som ett hjälpverktyg vid utvärdering och klassificering av komponenter men även vid bedömning av de tillhandahållande leverantörerna. I high tech-bolag är inköpsavdelningen ofta något mindre prioriterad relativt forsknings- och utvecklingsavdelningen. COMPASS-ramverket är designat för att skapa objectivitet eftersom ekonomiska och tekniska kompetenser är polariserade mellan de olika divisionerna. Som ett hjälpverktyg tillsammans med Kraljics portföljmodell tillåts företag säkerställa att sina begränsade resurser kan få en adekvat fördelning samt förbättra förutsättningarna för effektiv sourcing. Genom att applicera COMPASS-ramverket på Sony Ericsson har inte bara leverantörsberoendet minskat, utan validiteten och applicerbarheten av ramverket har även säkerställts

Chronology of laramide magmatism and stockwork fracture filling at the Red Hills porphyry Mo-Cu deposit, Presidio County, Texas

textThe Red Hills intrusive complex is the easternmost porphyry Mo-Cu system of Laramide age in southwestern North America. This study constrains the timing between igneous phases, and compares their geochemical characteristics with dikes from the Shafter silver deposit in order to support a possible link to a similar magmatic source. In addition, this study is the first to utilize SEM-CL techniques to document veining in a porphyry Mo system, comparing those to porphyry Cu systems. The high-K calc-alkaline igneous complex consists of early biotite porphyry (BP), biotite quartz monzonite porphyry (BQMP), quartz monzonite porphyry (QMP), quartz latite porphyry (QLP), and granodiorite porphyry (GP) with microgranular mafic enclaves. These magmas intruded Permian sandstones, siltstones, and dolostones, resulting in an extensive hornfels zone with local garnet skarn. U-Pb ages of zircon from the QLP and BQMP are 62.54 ± 0.49 Ma and 66.08 ± 0.31 Ma ages, respectively. When integrated with Gilmer's (2001) 60.2 ± 0.3 Ma molybdenite Re-Os age and ⁴⁰Ar/³⁹Ar sericite age of 61.58 ± 0.34 Ma, magmatism and hydrothermal activity may have spanned at least 6 My at Red Hills. Whole-rock and trace-element geochemistry suggest the Red Hills intrusions are sourced from an intermediate crustal melt and share a similar geochemical parent as dikes found in the Shafter carbonate-replacement-silver deposit. Potassic alteration is found in deep BP intercepts as mm-scale K-spar alteration halos and as shreddy biotite, which is pervasively overprinted by phyllic alteration. Intermediate argillic alteration caps the phyllic alteration zone and propylitic alteration extends east of the western mineralized part at Red Hills. Mo-Cu mineralization at Red Hills is confined to stockwork quartz veins and as disseminations within hydrothermally altered wallrock. The Red Hills intrusions have similar vein styles and, from youngest to oldest, the stockwork veining sequence involves: A veins (A1 and A2), B veins, D veins (D1 and D2), and hypogene alunite veins. Mo mineralization is confined to B veins and copper mineralization occurs later from phyllic overprinting in the form of copper sulfide inclusions in pyrite in wallrock and in D veins. SEM-CL of hydrothermal quartz reveals intricate quartz textures in relation to sulfide deposition within complex stockwork veins where fracture overprinting is common. A sequence of three stages of main-stage vein development and has been developed: 1) Fracturing in a semi-plastic magma formed sinuous veins filled with granular quartz that has internal wavy growth zones or homogenous CL texture. 2a) Fracturing under brittle conditions formed planar veins with euhedral, inward-oriented quartz that has oscillatory growth zones and bright luminescence. 2b) molybdenite deposition sites are associated with local dark-CL quartz in early quartz, while retaining primary growth textures. 3a) Dissolution of early quartz by retrograde solubility formed embayments along quartz grain boundaries. Following dissolution, euhedral, dark-CL quartz precipitated coevally with pyrite enriched in copper. When the hydrothermal activity ends, tectonic activity resulted in dark-CL microfractures and partial recrystallization may affect the stockwork veins.Geological Science

Neuro-Evolution for Emergent Specialization in Collective Behavior Systems

Eiben, A.E. [Promotor]Schut, M.C. [Copromotor