Trading strategies and trading profits in experimental asset markets with cumulative information

We study the use of trading strategies and their profitability in experimental asset markets with asymmetrically informed traders. We find that insiders make most of their profits from trades which are initiated by their limit orders especially at the beginning of a period and when the change in their fundamental information is large. The average informed lose most with market orders and their losses are highest at the beginning of a period when they can be exploited by insiders. Uninformed traders act as liquidity providers. They place the highest number of limit orders and end up with the market return

Bubble or no Bubble - The Impact of Market Model on the Formation of Price Bubbles in Experimental Asset Markets

For the past two decades a market model introduced by Smith, Suchanek, and Williams (1988, henceforth SSW) has dominated experimental research on financial markets. In SSW the fundamental value of the traded asset is determined by the expected value of a finite stream of dividend payments. This setup implies a deterministically falling fundamental value with a predetermined end of the life-span of the asset and extremely high dividend-payouts. We present a new market model in which we implement the fundamental value by adopting a random walk process. Compared to SSW-markets, prices in the new markets (SAVE) are more efficient and end-of-experiment imbalances common in SSW-markets are not observed. Our results demonstrate, that implicit features of the SSW market model contribute to bubble formation

Verlauf Endothelialer Vorgängerzellen (EPC) bei monopolardepressiven Patienten unter dem Einfluss antidepressiver Medikamente

In 2009 a first report showed that Endothelial Progenitor Cells could play a role in affective disorders (DOME et al. 2009). So this article focuses if there is any development of endothelial progenitor cells in depressed patients during their stay in hospital and tries to identify possible influencing factors such as age, sex or drugs. We also had a look at the so called circulating endothelial cells (CECs), with some really interesting results. In observing the development of EPCs and leukocytes in depressive patients during their stay at the clinic, especially the development of CD146-positive cells seems to be very interesting. The results suggest that the significant decrease of the CD146 positive cells could be correlated (because of the improved mood of patients at discharge) with an improvement of the vascular situation. This could be associated with neoangiogenesis in that areas of the brain, in which a decrease in volume is already described in depressed patients. The results of the leucocytes support once more the stress hypothesis of depression. This is evidenced by the increased leucocyte cell count on admission and their significant decrease until the end of therapy.Nachdem 2009 bekannt wurde, dass Endotheliale Vorgängerzellen bei Depressionen eine Rolle spielen können (DOME et al. 2009), nimmt sich diese Dissertation zum Thema, wie sich die Endothelialen Vorgängerzellen bei depressiven Patienten im Verlauf ihres stationären Aufenthalts entwickeln, und versucht mögliche Einflussfaktoren wie Alter, Geschlecht oder Medikamente zu identifizieren. Dabei wird auch ein besonderes Augenmerk auf die Entwicklung der Gruppe der Zirkulierenden Endothelialen Zellen (CECs) gelegt. Bei der Beobachtung des Verlaufs der EPCs und Leukozyten von depressiven Patienten während ihres Aufenthalts in der Psychiatrischen Universitätsklinik Erlangen scheint vor allem die Entwicklung der CD146 positiven Zellen sehr interessant. Die Ergebnisse lassen darauf schließen, dass der signifikante Abfall der CD146 positiven Zellen im Verlauf der Behandlung aufgrund der gebesserten Stimmungslage der Patienten bei Entlassung mit einer Verbesserung der Gefäßsituation zusammenhängt. Dies könnte mit Neoangiogenese in den Gebieten des Gehirns vergesellschaftet sein, in welchen bei depressiven Patienten eine Volumenabnahme beschrieben wird. Die Leukozytenergebnisse untermauern einmal mehr die Stresshypothese der Depression. Dies wird durch die erhöhten Leukozytenwerte bei Aufnahme und ihren signifikanten Abfall bis zum Ende der Therapie deutlich

Vergleichende bilaterale magnetresonanztomographische Untersuchung der Hufregion im Niederfeld-MRT

Durch die Einführung der MRT-Untersuchung am stehenden sedierten Pferd ist deren Anzahl deutlich angestiegen. Hierbei stellen sich neue Fragen und Herausforderungen bezüglich der Einschätzung der Vielzahl an auftretenden Signalveränderungen. Es ergeben sich aber auch neue Möglichkeiten bezüglich der statistischen Auswertung von Befunden mit aussagekräftigen Fallzahlen. In dieser Studie sollte daher untersucht werden, wie Signalveränderungen statistisch verwendbar beschrieben und eingestuft werden können. Weiterhin sollte die Verteilung der Befunde insgesamt und bei der bilateralen Untersuchung der Vordergliedmaßen bestimmt werden. Mögliche Rückschlüsse auf deren klinische Bedeutung sollten gezogen werden. Hierzu wurden 120 bilaterale Niederfeld-MRT-Untersuchungen der Hufregion (240 Gliedmaßen) am stehenden Pferd durch zwei Tierärzte gesichtet und eine Befundbeschreibung mit einem Einstufungsschema (Grade 1-4) entsprechend dem vorgefundenen Spektrum an Signalveränderungen erstellt. Durch Anwendung und Zusammenfassung 66 wiederholte Diskussion der verschiedenen Kriterien im 1. Bewertungsdurchgang wurden die Beschreibungen und Grade auf Grundlage bestehender Literatur ausgearbeitet. In einem 2. Bewertungsdurchgang wurden die Strukturen eingestuft und die Ergebnisse statistisch ausgewertet. Hierbei wurden die generellen Häufigkeiten der Signalabweichungen erfasst und deren Zusammenhang zum Auftreten von unilateralen oder bilateralen Lahmheiten beachtet. Signalabweichungen am Strahlbein, der Tiefen Beugesehne und dem Hufgelenk standen deutlich im Vordergrund. Hierbei waren Strahlbeinveränderungen signifikant häufiger bei beidseitig lahmen Pferden zu finden, während Sehnenveränderungen deutlich häufiger bei einseitig lahmen Pferden vorgefunden wurden. Hufgelenkveränderungen wurden hingegen nicht signifikant vermehrt bei bilateralen oder unilateralen Lahmheiten festgestellt. Die Fesselbein-Strahlbein-Hufbeinbänder zeigten eine Häufung von Signalabweichungen bei lahmen Gliedmaßen, wobei diese vermehrt in Zusammenhang mit starken Veränderungen des Strahlbeins zu beobachten waren. Bei den übrigen Strukturen ließ sich kein statistisch aussagekräftiger Zusammenhang feststellen, da die Fallzahlen mit dem deutlichsten Befund an diesen Strukturen zu gering für eine Auswertung waren. Die entstandene Befundbeschreibung mit Einstufungsschema ermöglicht Vergleiche der MRT-Veränderungen z.B. mit klinischen Parametern. Signalabweichungen bestimmter Strukturen konnten statistisch eindeutig mit dem Auftreten und der Art der Lahmheit in Verbindung gebracht werden, während dies bei anderen Strukturen nicht möglich war. Hieraus ergeben sich Hinweise für die Einschätzung der Befunde und ihrer klinischen Relevanz. Insbesondere geringgradige Befunde sollten vorsichtig bewertet werden, da diese auch häufig bei nicht lahmen Gliedmaßen auftraten. Weitere statistische Vergleiche mit klinischen Parametern sind möglich und notwendig um das Krankheitsbild des „Equinen palmaren Fußsyndroms“ weiter zu untersuchen.As a result of adopting MRI examinations for standing sedated horses their number has increased significantly. In this respect there are new questions and challenges being faced regarding estimating the huge number of occurring signal changes. New possibilities also arise regarding the statistical analysis of findings with convincing number of examined cases. In this study therefore it should be investigated how signal changes can be suitably described and classified statistically. Furthermore, the distribution of the findings as a whole and in the bilateral investigations of the forelimbs should be ascertained. Possible conclusions should be drawn regarding their clinical significance. Concerning this, 120 bilateral low-field-MRI examinations of the foot (240 limbs) on a standing horse were looked at by two veterinarians and a description of the analysis with a classification scheme (grades 1-4) corresponding to the existing spectrum of signal changes was compiled. By applying and repeatedly discussing the various Summary 68 criteria in the first evaluation round the descriptions and grades were worked out on the basis of existing literature. In a second evaluation round the structures were classified and the results statistically evaluated. In this regard the general frequency of signal deviations was recorded and its connection to the occurrence of unilateral or bilateral lameness was observed. Signal deviations at the navicular bone, deep digital flexor tendon and the coffin joint noticeably prevailed. In this respect changes to the navicular bone were found significantly more frequently in bilaterally lame horses while changes in tendons were found significantly more often in unilaterally lame horses. In contrast, changes in the coffin joint were not significantly more in bilateral or unilateral lameness. The collateral sesamoidean ligaments showed an accumulation of signal deviations at lame limbs, whereby this was observed more frequently in connection with pronounced changes of the navicular bone. In the remaining structures no statistically significant connection was found as the number of examined cases with the most significant results at these structures was too low for an evaluation. The related description of the findings with a classification scheme enables comparisons of MRI changes e.g. with clinical parameters. Signal deviations of certain structures were found to be clearly statistically associated with the occurrence and type of lameness, while this was not possible at other structures. This provides useful information for evaluating findings and their clinical relevance. Low-grade findings should be interpreted with caution since these also occurred frequently at non-lame limbs Further statistical comparisons with clinical parameters are possible and necessary in order to further examine the clinical picture of the equine palmar foot syndrome

Investment Horizons and Price Indeterminacy in Financial Markets

We examine how different investment horizons, and consequently the number of hands through which a security passes during its life, affect prices in a laboratory market populated by overlapping generations of investors. We find that (i) price deviations are larger in markets populated only by short-horizon investors compared to markets with long-horizon investors; (ii) for a given maturity of security, price deviations increase as investment horizons shrink (and frequency of transfers increases); and (iii) short investment horizons create upward pressure on prices when liquidity is high and downward pressure when liquidity is low

Hot Hand Belief and Gambler's Fallacy in Teams: Evidence from Investment Experiments

In laboratory experiments we explore the effects of communication and group decision making on investment behavior and on subjects proneness to behavioral biases. Most importantly, we show that communication and group decision making does not impact subjects overall proneness to biases like gamblers fallacy and hot hand belief. However, groups decide differently than individuals as they rely significantly less on useless outside advice from experts and choose the risk-free option less frequently. Finally, we document gender differences in investment behavior: groups of two female subjects choose the risk-free investment more often and are slightly more prone to the hot hand belief than groups of two male subjects

Speculation and Price Indeterminacy in Financial Markets: An Experimental Study

To explore how speculative trading influences prices in financial markets, we conduct a laboratory market experiment with speculating investors (who do not collect dividends and trade only for capital gains) and dividend-collecting investors. Moreover, we operate markets at two different levels of money supply. We find that in phases with only speculating investors present (i) price deviations from fundamentals are larger; (ii) prices are more volatile; (iii) mispricing increases with the number of transfers until maturity; and (iv) speculative trading pushes prices upward (downward) when the supply of money is high (low). These results suggest that controlling the money supply can help to stabilize asset prices

Success Factors of Communities for User Driven Content: the Case of Ciao.com

Virtual communities that produce “user driven content ” are a relatively new phenomenon. In this study we present the findings of an exploratory empirical study that focus on the success factors that stimulate content production from the perspective of community members. One main finding is that methods or tools that advance the transparency of what is going on in the community platform results in more content production. This accents the importance of new tools like RSS for example. Furthermore an ambiguous role of sociological motives was found. On the one hand there is statistical evidence that sociological motives and content production activities are closely linked. But on the other hand our descriptive data indicates only very weak sociological forces at work. We discuss some causes that may explain this result. KEYWORDS: Virtual communities, user driven content, exploratory empirical stud

Frequency- adaptive control of a three-phase single-stage grid-connected photovoltaic system under grid voltage sags

The low-voltage ride-through service is carried out in this paper according to the voltage profile described by the IEC 61400-21 European normative when short-duration voltage sags happen, and some instantaneous reactive power is delivered to the grid in accordance with the Spanish grid code; the mandatory limitation of the amplitude of the three-phase inverter currents to its nominal value is carried out with a novel control strategy, in which a certain amount of instantaneous constant active power can also be delivered to the grid when small or moderate voltage sags happen. A Multiple second order generalized integrator frequency-locked loop synchronization algorithm is employed in order to estimate the system frequency without harmonic distortions, as well as to output the positive- and the negative- sequence of the αβ quantities of the three-phase grid voltages when balanced and unbalanced voltage sags happen in a frequency- adaptive scheme. The current control is carried out in the stationary reference frame, which guarantees the cancellation of the harmonic distortions in the utility grid currents using a Harmonic compensation structure, and the implementation of a constant active power control in order to protect the DC link capacitor from thermal stresses avoiding the appearance of large harmonic distortions at twice the fundamental frequency in the DC link voltage. A case study of a three-phase single-stage grid-connected PV system with a maximum apparent power about 500 kVA is tested with several simulations using MATLAB/SIMULINK firstly, and secondly, with some experiments using the Controller hardware-in-the-loop (CHIL) simulation technique for several types of voltage sags in order to do the final validation of the control algorithms.This work was supported by the project “Nuevas topologías para convertidores en MT para grandes Instalaciones Fotovoltaicas” from the Spanish Government (Ref. TEC2016-80136-P) (A. B. Rey-Boué) and the European Community’s Horizon 2020 Program (H2020/2014-2020) in project “ERIGrid” (Grant Agreement No. 654113) under the Trans-national Access (TA) User Project: 04.003-201