Country-Specific Effects of Reputation and Information: A Comparison of Online Auctions in Germany, the UK, and the US

Empirical studies on the effect of sellers’ reputation on closing prices in online auctions present mixed results. A large number of studies addresses reputational effects in one country, especially in the US. Only a small number of cross-country studies inspect the moderating role of institutional frameworks on bidder behavior. The purpose of this paper is to examine if country-specific differences in the formal and informal institutional framework influence the effects of reputation and information signals on final prices in online auctions. From the perspective of the New Institutional Economics, management decisions and individuals’ characteristics are affected by the institutional framework, which consists of cultural aspects as well as a set of social and legal rules and regulations. Therefore, bidders that are influenced by one institutional framework have different preferences, expectations, and perceptions about reputation and information in online auctions than individuals socialized by another institutional framework. In order to examine the effects of reputation and information on prices as well as to asses cross-country similarities and differences in these effects, a sample of 6,166 homogenous online auctions, conducted on the respective eBay websites in Germany, the UK, and the US, is analyzed. The results suggest that either the effects of reputation and product information variables vary significantly across countries or that different variables have an impact on prices in different countries. It can be concluded that country-specific institutional frameworks influence bidder behavior in international online auction markets.reputation, information, online auctions, cross-country studies

Treatment with rapamycin or rapamycin in combination with metformin contributes to mechanisms of mitochondrial proteostasis in vivo and in vitro

2018 Spring.Includes bibliographical references.This dissertation describes three sets of experiments with an overall objective of understanding how lifespan-extending treatments influence mechanisms of mitochondrial protein homeostasis (proteostasis). The specific aims of the three experiments were to 1) determine how the mTORC1 inhibitor rapamycin (Rap), or the anti-diabetes medication metformin in combination with rapamycin (Met+Rap) influence mitochondrial protein synthesis in young mice, and to determine if there are sex-specific differences in protein synthesis following treatment with Rap or Met+Rap; 2) examine the influence of Met+Rap treatment on protein synthesis in the heart, liver, and skeletal muscle of older mice and to determine if there are sex-specific differences in protein synthesis following Met+Rap treatment in old mice; 3) and, finally, to investigate the regulation of how protein turnover contributes to maintaining proteostasis during Rap and Met+Rap treatment, and the contribution of autophagic and mitophagic flux to protein turnover in cultured skeletal myotubes. In the first experiment, both Rap and Met+Rap treatments lowered mitochondrial protein synthesis in male mice compared to control in skeletal muscle. However, in female mice, only Met+Rap treatment significantly lowered skeletal muscle mitochondrial protein synthesis compared to control. Additionally, both Rap and Met+Rap treatments significantly elevated skeletal muscle mitochondrial protein synthesis in female animals compared to males. However, in the heart and liver tissue, there were no differences in mitochondrial protein synthesis between treatments or sexes. In the second experiment, Met+Rap treatment lowered protein synthesis in all three tissues, but in a fraction-specific manner. independent of sex-differences in old mice. For the third experiment, we measured protein synthesis and protein breakdown in cultured skeletal myotubes treated with Rap and Met+Rap. Rap treatment significantly increased mitochondrial protein:DNA compared to control, while Met+Rap did not. We demonstrate that autophagic flux is a large (29%) contributing process to degradation of mitochondrial proteins. Additionally, mitochondrial fission is not essential for mitochondrial protein degradation. The data from these experiments demonstrate that despite sexually dimorphic effects on lifespan, Rap and Met+Rap treatments both enhance the contribution of protein synthesis to maintaining proteostasis in vivo. Further, we demonstrate that both Rap and Met+Rap treatment increased protein:DNA in cultured skeletal myotubes. In summary, these data demonstrate that Rap and Met+Rap treatments increase proteostatic mechanisms, and further research is required to improve the understanding of how Met+Rap treatment influences lifespan

Country-Specific Effects of Reputation and Information: A Comparison of Online Auctions in Germany, the UK, and the US

Empirical studies on the effect of sellers' reputation on closing prices in online auctions present mixed results. A large number of studies addresses reputational effects in one country, especially in the US. Only a small number of cross-country studies inspect the moderating role of institutional frameworks on bidder behavior. The purpose of this paper is to examine if country-specific differences in the formal and informal institutional framework influence the effects of reputation and information signals on final prices in online auctions. From the perspective of the New Institutional Economics, management decisions and individuals' characteristics are affected by the institutional framework, which consists of cultural aspects as well as a set of social and legal rules and regulations. Therefore, bidders that are influenced by one institutional framework have different preferences, expectations, and perceptions about reputation and information in online auctions than individuals socialized by another institutional framework. In order to examine the effects of reputation and information on prices as well as to asses cross-country similarities and differences in these effects, a sample of 6,166 homogenous online auctions, conducted on the respective eBay websites in Germany, the UK, and the US, is analyzed. The results suggest that either the effects of reputation and product information variables vary significantly across countries or that different variables have an impact on prices in different countries. It can be concluded that country-specific institutional frameworks influence bidder behavior in international online auction markets

Power limits and a figure of merit for stimulated Brillouin scattering in the presence of third and fifth order loss

We derive a set of design guidelines and a figure of merit to aid the engineering process of on-chip waveguides for strong Stimulated Brillouin Scattering (SBS). To this end, we examine the impact of several types of loss on the total amplification of the Stokes wave that can be achieved via SBS. We account for linear loss and nonlinear loss of third order (two-photon absorption, 2PA) and fifth order, most notably 2PA-induced free carrier absorption (FCA). From this, we derive an upper bound for the output power of continuous-wave Brillouin-lasers and show that the optimal operating conditions and maximal realisable Stokes amplification of any given waveguide structure are determined by a dimensionless parameter $\mathcal{F}$ involving the SBS-gain and all loss parameters. We provide simple expressions for optimal pump power, waveguide length and realisable amplification and demonstrate their utility in two example systems. Notably, we find that 2PA-induced FCA is a serious limitation to SBS in silicon and germanium for wavelengths shorter than 2200nm and 3600nm, respectively. In contrast, three-photon absorption is of no practical significance

Impact of nonlinear loss on Stimulated Brillouin Scattering

We study the impact of two-photon absorption (2PA) and fifth-order nonlinear loss such as 2PA-induced free-carrier absorption in semiconductors on the performance of Stimulated Brillouin Scattering devices. We formulate the equations of motion including effective loss coefficients, whose explicit expressions are provided for numerical evaluation in any waveguide geometry. We find that 2PA results in a monotonic, algebraic relationship between amplification, waveguide length and pump power, whereas fifth-order losses lead to a non-monotonic relationship. We define a figure of merit for materials and waveguide designs in the presence of fifth-order losses. From this, we determine the optimal waveguide length for the case of 2PA alone and upper bounds for the total Stokes amplification for the case of 2PA as well as fifth-order losses. The analysis is performed analytically using a small-signal approximation and is compared to numerical solutions of the full nonlinear modal equations

Clarification of the circulatory patho-physiology of anaesthesia - Implications for high-risk surgical patients

AbstractThe paper examines the effects of anaesthesia on circulatory physiology and their implications regarding improvement in perioperative anaesthetic management. Changes to current anaesthetic practice, recommended recently, such as the use of flow monitoring in high risk patients, are already beginning to have an impact in reducing complications but not mortality [1]. Better understanding of the patho-physiology should help improve management even further. Analysis of selected individual clinical trials has been used to illustrate particular areas of patho-physiology and how changes in practice have improved outcome. There is physiological support for the importance of achieving an appropriate rate of oxygen delivery (DO2), particularly following induction of anaesthesia. It is suggested that ensuring adequate DO2 during anaesthesia will avoid development of oxygen debt and hence obviate the need to induce a high, compensatory, DO2 in the post-operative period. In contrast to the usual assumptions underlying strategies requiring a global increase in blood flow [1] by a stroke volume near maximization strategy, blood flow control actually resides entirely at the tissues not at the heart. This is important as the starting point for understanding failed circulatory control as indicated by ‘volume dependency’. Local adjustments in blood flow at each individual organ – auto-regulation – normally ensure the appropriate local rate of oxygen supply, i.e. local DO2. Inadequate blood volume leads to impairment of the regulation of blood flow, particularly in the individual tissues with least capable auto-regulatory capability. As demonstrated by many studies, inadequate blood flow first occurs in the gut, brain and kidney. The inadequate blood volume which occurs with induction of anaesthesia is not due to blood volume loss, but probably results from redistribution due to veno-dilation. The increase in venous capacity renders the existing blood volume inadequate to maintain venous return and pre-load. Blood volume shifted to the veins will, necessarily, also reduce the arterial volume. As a result stroke volume and cardiac output fall below normal with little or no change in peripheral resistance. The resulting pre-load dependency is often successfully treated with colloid infusion and, in some studies, ‘inotropic’ agents, particularly in the immediate post-operative phase. Treatment during the earliest stage of anaesthesia can avoid the build up of oxygen debt and may be supplemented by drugs which maintain or restore venous tone, such as phenylephrine; an alternative to volume expansion. Interpretation of circulatory patho-physiology during anaesthesia confirms the need to sustain appropriate oxygen delivery. It also supports reduction or even elimination of supplementary crystalloid maintenance infusion, supposedly to replace the “mythical” third space loss. As a rational evidence base for future research it should allow for further improvements in anaesthetic management

Retrospektive Analyse von Post-Processing-Algorithmen für digitale Röntgen-Thorax-Aufnahmen in der Neonatologie

In dieser Studie wurden die Post-Processing-Variationen S-Vue™ 3.02 Neonatal 1 - 4 bezüglich ihres Einflusses auf die Bildqualität von digitalen Röntgenaufnahmen untersucht. Ziel dieser Studie war es, zu untersuchen, ob diese Post-Processing-Variationen zu einer Verbesserung der Bildqualität von digitalen Röntgen-Thorax-Aufnahmen führen. 50 Röntgen-Thorax-Aufnahmen wurden postprozessiert und durch drei Fachärzte für Radiologie analysiert. Die deskriptive Häufigkeitsverteilung sowie die Inter-Rater-Reliabilität wurde ermittelt und eine Summenvektorberechnung durchgeführt. Die Ergebnisse der Summenvektorberechnung sind mit einem t-Test für verbundene Stichproben auf Signifikanz überprüft worden. Für die Post-Processing-Variation S-Vue™ 3.02 Neonatal 1 wurde sich am häufigsten bei den Kriterien Lungenstruktur (35,3 %) und zentrale Gefäße (38 %) entschieden. Bei der Beurteilung von retrokardialen Gefäßen (38,7 %) und bei dem Kriterium Rauscheindruck (44,7 %) wurde der Prozess Neonatal 2 präferiert. Neonatal 3 erhielt bei den Bewertungskriterien Knochenstruktur (48,7 %), Trachea (32,7 %) und Fremdmaterial (48 %) die beste Bewertung. Bei der Beurteilbarkeit im Sinne der Fragestellung (36,7 %) und der Beurteilung von Pneumothoraces (41,7 %) wurde Neonatal 4 am besten bewertet. Die Kappa-Koeffizienten lagen bei Werten von - 0,143 bis 0,2. Die Berechnung des Summenvektors und des t-Tests führte zu dem Ergebnis, dass Prozess Neonatal 4 mit 4,04 von 16 Punkten am besten bewertet wurde. Signifikant am schlechtesten wurde der Prozess 3 mit 2,54 Punkten bewertet (P < 0,05). Die deskriptive Häufigkeitsverteilung zeigt, dass die Post-Processing-Variationen für bestimmte Fragestellungen eine unterschiedlich gute Bildqualität liefern. Die geringen Werte der Kappa-Koeffizienten bedeuten ein niedriges Maß an Übereinstimmung zwischen den Radiologen. Durch die Berechnung des Summenvektors und des t-Tests konnte kein Verfahren dargelegt werden, welches signifikant besser bewertet wurde