Getting better or getting worse? Consumer responses to decreasing, constant, and ascending multi-dimensional price profiles

This research investigates consumer preferences for different multi-dimensional price profiles. Drawing on research on price affect, we investigate whether consumers prefer descending monthly installments (e.g., 40, 30, 20, 10) over constant (e.g., 25, 25, 25, 25), or ascending ones (e.g., 10, 20, 30, 40). Results of a field experiment with a sample of 1,628 German car buyers corroborate the hypothesized profile effect. In the experiment, participants were asked to evaluate different finance offers for a new car that all had the same present value but differed in terms of how the installments unfolded over time. Consistent with the hypotheses, decreasing monthly installments are evaluated more favorably than constant installments, which, in turn are evaluated more favorably than ascending installments. Furthermore, the results provide evidence for the underlying process by showing that the impact of different MDP profiles is mediated by positive affect. Finally, it was hypothesized that consumers' individual differences (i.e., debt aversion, financial expectations, and product category knowledge) would exert a moderating influence on evaluations of different price profiles; these hypotheses, however, were only partially confirmed. Theoretical and managerial implications are discusse

COMPUTER-GENERATED CARS YOU HAVE TO LOVE: HOW IMAGE MORPHING AND WARPING HELP DESIGNERS TO OPTIMIZE THEIR DESIGN SKETCHES

Although product design is considered as a core determinant of a product\u27s market success, systematic approaches that allow managers to increase a product\u27s visual attractiveness are not available. The present research addresses this gap by adapting an approach that was originally developed in research on human facial attractiveness to a product design context. In particular, we propose that image morphing and warping techniques can be used to identify and manipulate those design features that drive a product\u27s perceived attractiveness. Moreover, we also develop a computer-assisted interface that allows consumers to individually determine their optimal car design. Three studies with real consumers focusing on the automotive market confirm the viability and the usefulness of our approach. From a managerial perspective, the approach may increase the effectiveness of design efforts and may help in integrating consumers\u27 preferences in an early stage of the product design process

Stability analysis of digital microwave power amplifiers

This work presents a stability analysis of microwave power amplifiers (PAs) driven by binary pulse trains, as in the case of class-S PAs. First, using a simplified digital PA test bench in class-D configuration, different qualitative behaviors are obtained when varying the pulsewidth, including subharmonic and incommensurable oscillations. The mechanisms affecting the stability properties are studied with a harmonic balance-based formulation, by means of pole-zero identification and bifurcation detection. A sufficiently high number of harmonic components must be considered, together with the Krylov decomposition for an efficient computation of the inverse of the Jacobian matrix. It is demonstrated that, when varying the pulsewidth, the distinct pairs of complex-conjugate poles may shift to the right-hand side of the complex plane and, therefore, lead to different kinds of unstable behavior. This phenomenon is related to the dependence of the critical poles on the average value of the input signal. Boundaries of the various types of unstable behavior are traced in the plane defined by the pulse repetition rate and pulsewidth, using bifurcation detection techniques. All the predicted phenomena have been confirmed experimentally. In a second step, the algorithms derived from the simple class-D circuit are transferred to study the stability of a more complex tri-band class-S amplifier. It has been analyzed versus the input bitrate, obtaining a fully stable behavior that has been validated experimentally.This work has been supported by the Spanish Government under contract TEC2014-60283-C3-1-R, the European Regional Development Fund (ERDF/FEDER) and the Parliament of Cantabria (12.JP02.64069)

The influence of stimulus ambiguity on category and attitude formation

Existing research on categorical ambiguity has mostly examined how consumers assimilate new products into familiar product categories. Extending these findings, this research investigates whether and under what circumstances consumers either create new mental categories for hybrid products or integrate them into existing categories. Specifically, we propose that this effect is influenced by the degree of product ambiguity and the availability of a new category label. We find that as ambiguity increases, the probability of new category creation augments, but product evaluation deteriorates. However, we also find that a new category label can reduce the effects of ambiguity and can improve product evaluation. Thus, the results fill the existing gap in research on the cognitive integration of hybrid products and shed light on how managers may position these products successfull

Buchbesprechungen aus Botanik und Naturschutz in Hessen Bd. 20

Folgende Publikationen werden rezensiert: Garve & al.: Verbreitungsatlas Niedersachsen, Hölzel & al.: Stromtalwiesen, Lübcke & Frede: Naturschutzgebiete in Hessen Band 4, Notizbuch 68 der Kasseler Schule, Riecken & al.: Rote Liste Biotoptypen, Schulz & Dengler: Verbreitungsatlas Moose Schleswig-Holstein, Szabo: Wandern – Erkennen – Heile

Population ecology and life-history tactics of shallow, sand-bottom crustaceans at Kaikoura

Quantitative random sampling of a shallow, sand bottom exposed to unpredictable storm wave action at Kaikoura, New Zealand, between Oct. 1978 and Oct. 1980 provided detailed information on the population biologies of five crustaceans, the large myodocopid ostracod Cyaloleberis zealandiaa, and the gammaridean amphipods Hippomedon whero, Patuki roperi, Metaphoxus littoralis and Paraphoxus australis. Data for each species included seasonal changes in population density and structure, cohort composition, age at maturity, longevity, frequency and occurrence of breeding, egg size, duration of embryonic development, brood size and mortality, number of instars and broods per life-time and population sex ratios. The biology of myodocopid ostracods is reviewed and discussed with respect to Cyaloleberis and the question of instar size variations in ostracods generally is explored. Results for the amphipods are discussed in relation to current knowledge of amphipod biology. Utilization of the sand habitat was examined by comparing species population densities and compositions in ripples and in troughs at different times. Species sediment-depth distributions in ripples and in troughs were investigated in two successive months by sectioning cores into five layers. In some species juveniles, males and females inhabited different depths and other species were more abundant in either ripples or troughs. Sediment depths inhabited are discussed with respect to species burrowing rates, food, and an optimal sediment depth where niche overlap, and presumably competition also, is greatest. Recolonization of defaunated sand by each species was monitored over 1, 4, 8, 16 and 26 days initially and over 1 and 26 - 39 days during each of five subsequent months. Initial results showed remarkably fast recolonization by some species and changes in species population densities as recolonization proceeded. Within species the relative recolonization rates of juveniles, males and females may differ along with the sizes of recolonizing and control species subgroups. However, the experiments in subsequent months revealed that the pattern of species recolonization may change with time in response to no obvious factors. Results of the preceeding chapters are brought together in a final discussion of crustacean life-history tactics. Sediment depths inhabited provided a ranking of species habitat stabilities and mortality risks, both greatest at the sand surface. Population parameters, including net reproductive rates and innate capacities for increase, confirmed the ranking, but comparisons with species combinations of life-history traits strongly disagree with the predictions of two theories, r- and K-selection and bet-hedging. The failure of these theories is principally due to the existence of phylogenetic constraints, the lack of viable genetic alternatives for a trait. A new theory is required that encompasses phylogenetic constraints and recognizes the possibility of several equally successful combinations of traits in a given situation. Such a theory based on established ideas of costs of reproduction and of larger offspring from larger eggs being ecologically fitter must incorporate recent ideas on growth rates, body size and size-specific mortality

Isolation and genome sequencing of four Arctic marine Psychrobacter strains exhibiting multicopper oxidase activity

Moghadam MS, Albersmeier A, Winkler A, et al. Isolation and genome sequencing of four Arctic marine Psychrobacter strains exhibiting multicopper oxidase activity. BMC Genomics. 2016;17(1): 117

In-vitro and in-vivo imaging of coronary artery stents with Heartbeat OCT

To quantify the impact of cardiac motion on stent length measurements with Optical Coherence Tomography (OCT) and to demonstrate in vivo OCT imaging of implanted stents, without motion artefacts. The study consists of: clinical data evaluation, simulations and in vivo tests. A comparison between OCT-measured and nominal stent lengths in 101 clinically acquired pullbacks was carried out, followed by a simulation of the effect of cardiac motion on stent length measurements, experimentally and computationally. Both a commercial system and a custom OCT, capable of completing a pullback between two consecutive ventricular contractions, were employed. A 13 mm long stent was implanted in the left anterior descending branch of two atherosclerotic swine and imaged with both OCT systems. The analysis of the clinical OCT images yielded an average difference of 1.1 ± 1.6 mm, with a maximum difference of 7.8 mm and the simulations replicated the statistics observed in clinical data. Imaging with the custom OCT, yielded an RMS error of 0.14 mm at 60 BPM with the start of the acquisition synchronized to the cardiac cycle. In vivo imaging with conventional OCT yielded a deviation of 1.2 mm, relative to the length measured on ex-vivo micro-CT, while the length measured in the pullback acquired by the custom OCT differed by 0.20 mm. We demonstrated motion artefact-free OCT-imaging of implanted stents, using ECG triggering and a rapid pullback

Class-S Microwave Power Amplifiers with GaN Transistors

Die Arbeit präsentiert eine umfassende Analyse des Klasse-S-Konzepts im Mikrowellen-Frequenzbereich. Es werden Voltage-Mode (VMCS) und Current-Mode (CMCS) Klasse-S-Verstärker, die auf GaN-MMICs basieren, für das 450 MHz – Band entworfen, realisiert und messtechnisch charakterisiert. Die Beiträge der Arbeit gliedern sich in drei Hauptthemen. Zunächst wird ein Zeitbereichsmessplatz zur Analyse der in den Klasse-S-Verstärkern benutzten GaN Leistungsschalter-MMICs und ein Schalter-basiertes Transistormodell für Großsignalsimulationen von Schaltverstärkern im Zeitbereich, welches den direkten Zugang zu den parasitären Elementen des Transistors ermöglicht, entwickelt. Der Schwerpunkt dieser Arbeit liegt auf dem Entwurf, der Optimierung und der Analyse von Klasse-S-Verstärkern unter besonderer Betrachtung der dazugehörigen Ausgangsnetzwerke. Es wird eine detaillierte theoretische und praktische Untersuchung der Netzwerke für Voltage-Mode- und Current-Mode-Aufbau durchgeführt. Sie sind Schlüsselelemente für die Funktionsweise und die Effizienz des Klasse-S-Konzepts, besonders im Current-Mode, bei dem das Filter einen differentiellen Eingang hat. Realisiert wurden Verstärker sowohl in Current-Mode- (CMCS) als auch in Voltage-Mode-Topologie (VMCS) für das 450 MHz – Band. Die erreichten Ergebnisse stellen einen bedeutenden Fortschritt für den „State-of-the-Art“ von Klasse-S-Verstärkern im Mikrowellen-Frequenzbereich dar. Im Klasse-S-Betrieb mit einer 1-Ton Bandpass-ΔΣ (BPDS) Bitsequenz erreichen die VMCS- und CMCS-Verstärker Spitzeneffizienzen von 50 % und 41 % bei maximalen Ausgangsleistungen (Paus) von 3,4 W bzw. 9 W. Vermindert man die kodierte Signaleingangsleistung um 10 dB, dann fällt die Draineffizienz jedoch unter 10 %. Nach der Identifizierung der Hauptverlustmechanismen wurden verschiedene Ansätze zur Verbesserung der Effizienz, speziell bei power back-off, untersucht. Die Variation der Überabtastrate des BPDS-modulierten Signals führt zu keinen signifikanten Verbesserungen. Die Kodiereffizienz der Modulation jedoch spielt eine Schlüsselrolle im Hinblick auf Effizienz und Paus. Mit einem periodischen Rechtecksignal am Eingang, welches die maximale Kodiereffizienz aufweist, können Paus und Effizienz im Vergleich mit den BPDS-Resultaten annähernd verdoppelt werden. Im Zuge der Untersuchungen zur Kodierung des Eingangssignals wurden die Klasse-S-Verstärker auch mit einer Pulsweitenmodulation (PWM) zur Kodierung der Amplitude im back-off-Betrieb gestestet. Dabei zeigt eine Version des VMCS-Aufbaus ohne Freilaufdioden nun 83 % Draineffizienz bei Vollaussteuerung (Paus = 3 W) und eine Verbesserung bei 10 dB power back-off von 11 % (BPDS) auf 40 %. Die Effizienz des Current-Mode-Verstärkers erhöht sich mit solch einem PWM-Signal auf 20 % bei 10 dB back-off (10 % bei BPDS). Die erreichten Resultate bilden eine ausgezeichnete Grundlage für weitere Verbesserungen des Klasse-S-Konzepts im Hinblick auf Effizienz, speziell bei hohen power back-offs.This thesis provides a comprehensive experiment-based analysis of the class-S concept in the microwave frequency range, reporting on design procedures and measurement results of realized voltage- (VMCS) and current-mode (CMCS) class-S power amplifiers (PA) based on GaN-MMICs for the 450 MHz band. The work contributes to three main topics. First of all a time-domain measurement setup to analyze the digital power MMICs used in the class-S PAs and a switch-based transistor model for large-signal simulations of switch-mode PAs in time-domain, which provides direct access to the parasitic elements of the transistor, is developed. The main focus of this thesis is on the design, optimization and analysis of class-S PAs with special emphasis on the appropriate output networks. A detailed theoretical and practical analysis of the circuits for the current- and voltage-mode topology is given. The importance of odd- and even-mode input impedances is discussed in detail. They are key issues in maintaining class-S functionality and efficiency, especially in current-mode operation where the filter has a differential input. Amplifiers in both current- (CMCS) and voltage-mode (VMCS) topology were realized. They operate in the 450 MHz band and significantly advanced the state-of-the-art of class-S PAs in the microwave range. For class-S operation using a single-tone band-pass-ΔΣ (BPDS) bit sequence, the built-up VMCS and CMCS amplifiers show peak efficiencies of 50% and 41% with maximum output powers (Pout) of 3.4 W and 9 W, respectively. Varying the encoded signal input power from 0 dB (full-scale) down to 10 dB, efficiency drops below 10%. After identifying the main loss mechanisms, different approaches to enhance efficiency, especially at power back-off, were investigated: The oversampling ratio of the BPDS scheme does not lead to significant improvements. But coding efficiency of the modulation plays a key role with regard to efficiency and Pout. Using a periodic square-wave input signal with maximum coding efficiency, both Pout and efficiency are almost doubled compared to BPDS values. Along with the investigations on the coding schemes, the class-S PAs were tested with a pulse-width modulation (PWM) for amplitude in back-off operation. A voltage-mode version without freewheeling diodes now shows 83% efficiency at full-scale (Pout = 3 W) and an improvement at 10 dB power back-off from 11% (BPDS) to 40%. The efficiency of the current-mode PA is increased to 20% at 10 dB back-off (10% for BPDS) with such a PWM input signal. The obtained results represent an excellent base for further improvements regarding efficiency at high power back-off levels using the class-S concept

The isolation, preliminary characterization and biotransformation of a mutagen produced by Fusarium moniliforme Sheldon

Thesis (M. Sc. Agric.) -- University of Stellenbosch, 1982.Full text to be digitised and attached to bibliographic record