Liquidity Effects of Changes in a Pan-European Stock Index

Adding or deleting a security to or from an index can influence the share price considerably. A possible explanation that has been brought forward in the literature is the liquidity hypothesis according to which an increase in liquidity after an addition is responsible for the observed rise in value. In the following paper, we examine liquidity effects on securities that have been added to or deleted from the pan- European index STOXX 50 between 1998 and 2003, using bid-ask spreads as indicators for liquidity. While there is a medium term price effect, bid-ask spreads do not change significantly due to the index addition or deletion. Regression analysis shows that the explanatory power of bid- ask spreads for the observed price effect is negligible. As a consequence of our empirical findings, the liquidity hypothesis has to be rejected for the STOXX 50. This result, however, does not appear particularly surprising, as the STOXX 50 is composed of already highly liquid securities whose trading liquidity appears not to depend on membership in an international index. A possible explanation for the rejection of the liquidity hypothesis is that the applicability of the liquidity hypothesis hinges on the liquidity class of the stocks concerned before being added. Marginal increases of liquidity due to an index addition might decline with larger initial liquidity of the stocks added. Subsequent studies could focus on the particular shape of this 'liquidity curve' of stocks.Pan-European stock index, index effect, STOXX, liquidity, price effect

Valuing Joint Ventures Using Real Options

As the valuation of strategic measures becomes increasingly important, relatively few articles have discussed the valuation methods pertained for joint ventures. This paper shows that real options contribute to a better valuation of joint venture projects through superior reflection of the value drivers compared to traditional valuation methodology. Particularly, the strategic value of a joint venture and the value of flexibility that stems from a less than full commitment can be determined using options valuation. Besides reviewing the basics of real options, the paper discusses the key levers of joint ventures and shows the power of real options in the valuation process. We apply four option types (option to defer, option to expand/acquisition option, option to innovate, and option to abandon) to an imaginary joint venture example and show how to use the Black/Scholes and binomial valuation techniques to value these options. Of the four option types, particularly the option to innovate is important, as it allows to reflect the strategic value of a joint venture generating future business opportunities. Despite its advantages, this valuation methodology also has some drawbacks that are discussed in the concluding section.Joint ventures, real options, option valuation, Black/Scholes model, binomial option valuation

Wavefront sensing in the human eye

Fortschritte in der chirurgischen Technik zur Korrektur von refraktionsbedingten Sehfehlern haben es ermöglicht, dass heute die Form der Hornhautvorderfläche auch ortsaufgelöst geändert werden kann. Die Refraktionsmessungen am menschlichen Auge beschränkten sich allerdings auf die Messung von Sphäre und Astigmatismus, und zwar bei einer einzigen Pupillengrösse. Im Zuge dieser Arbeit wurde - basierend auf einem Hartmann-Shack Sensor - ein Wellenfrontmessgerät zur ortsaufgelösten Refraktionsmessung des Auges entwickelt, das den diagnostischen Anforderungen gerecht wird, die sich aus den neuen Möglichkeiten der Augenchirurgie ergeben. Der Aufbau des Gerätes wird beschrieben. Die Ergebnisse von Messungen an Test-Optiken werden dargestellt und mit den theoretischen Möglichkeiten verglichen. Die Ergebnisse von Messungen an menschlichen Augen führen zu Einschätzungen über die tatsächliche und die erforderliche notwendige Auflösung des Geräts. Die Reproduzierbarkeit der Ergebnisse wird geprüft. Weitergehend wurde noch ein aktiver Senk-Matrix-Spiegel in das Gerät implementiert, der die Wellenfront korrigieren und dem Patienten seine aberrationsfreie Sehfähigkeit demonstrieren kann. Es zeigt sich: Das Gerät ist in der Lage, die Refraktionsmessungen einfach, schnell und reproduzierbar durchzuführen, und zwar mit einer Genauigkeit, die die Erfordernisse noch übertrifft

Quality of Life in Teduglutide-Treated Patients with Short Bowel Syndrome Intestinal Failure—A Nested Matched Pair Real-World Study

Background: Quality of life (QoL) data of chronic intestinal failure (cIF) patients treated with the GLP-2 analogue teduglutide are scarce. This study aims to analyze QoL changes over time in teduglutide-treated patients and compare the results to a matched non-treated cIF control group in a real-world setting. Methods: QoL data (SF-36 and SBS-QoL(TM)) were obtained from adult cIF patients being treated with teduglutide and compared to previously collected QoL data from a PNLiver trial (DRKS00010993), during which patients had been therapy naive. The dataset was then extended by a pairwise matched control group (non-teduglutide-treated PNLiver trial patients) and follow-up data from this group were collected accordingly. Results: Median teduglutide treatment duration and the follow-up period of controls were both 4.3 years. SBS-QoL(TM) subscales and the SBS-QoL(TM) sum score showed significant improvements over time in teduglutide-treated patients, as well as for the SF-36 physical and mental component summary scores (all p < 0.02), while non-treated patients showed no significant changes in any of the mentioned scores. Significant differences of QoL changes between treated and non-treated patients were seen for both SF-36 summary scores (p = 0.031 and 0.012). Conclusions: We herein demonstrate for the first time that QoL significantly improved during teduglutide treatment in SBS-cIF patients in a real-world setting compared to individually matched non-treated SBS-cIF patients, indicating relevant clinical benefits

Retreatment with interferon-alpha and ribavirin in primary interferon-alpha non-responders with chronic hepatitis C

Background/Aims: Combination therapy with interferon-alpha (IFN-alpha) plus ribavirin is more efficacious than IFN-alpha monotherapy in previously untreated patients with chronic hepatitis C and patients with IFN-alpha relapse. Only limited data are available in IFN-alpha non-responders. In a multicenter trial we therefore evaluated the efficacy of combination therapy in IFN-alpha-resistant chronic hepatitis C. Methods: Eighty-two patients (mean age 46.8 years, 54 males, 28 females) with chronic hepatitis C were treated with IFN-alpha-2a (3 x 6 MIU/week) and ribavirin (14 mg/kg daily) for 12 weeks. Thereafter, treatment was continued only in virological responders (undetectable serum HCV RNA at week 12) with an IFN-alpha dose of 3 x 3 MIU/week and without ribavirin for a further 9 months. The primary study endpoint was an undetectable HCV RNA by RT-PCR at the end of the 24-week follow-up period. Results: After 12 weeks of combination therapy, an initial virological response was observed in 29 of 82 (35.4%) patients. Due to a high breakthrough rate after IFN-a dose reduction and ribavirin discontinuation, an end-of-treatment response was only achieved in 12 of 82 (14.6%) patients. After the follow-up period, a sustained virological response was observed in 8 of 82 (9.8%) patients. Infection with HCV genotype 3 was the only pretreatment parameter, which could predict a sustained response (HCV-1, 5%; HCV-3, 57.1%; p < 0.001). Conclusions: Despite a high initial response rate of 35.4%, sustained viral clearance was achieved only in 9.8% of the retreated primary IFN-alpha non-responders. Higher IFN-alpha induction and maintenance dose, as well as prolonged ribavirin treatment may possibly increase the virological response rates in non-responders, particularly in those infected by HCV-1

Liver transplantation in primary biliary cirrhosis: Risk assessment and 11-year follow-up

Background/Aims: Liver transplantation (LTx) is the only established treatment in patients with end-stage primary biliary cirrhosis (PBC). Although short-term survival after LTx in this group of patients is usually good, few data exist on the long-term survival. The optimal timing of transplantation is difficult. Thus, the aims of this study were to assess the long-term survival of patients with PBC after LTx and to identify potential predictive factors for a positive outcome. Methods: Survival of 28 patients with PBC who underwent LTx between 1985 and July 1999 in a single center was studied by Kaplan-Meier analysis and was compared to predicted survival without LTx using established prognostic models for PBC, the Mayo and European risk scores. Potential prognostic parameters obtained before LTx were tested for correlation to survival. Rates of bone fractures as markers of hepatic osteodystrophy were compared before and after LTx. Results: Median follow-up after LTx was 90 months with a maximum of 140 months. Actuarial survival of patients with PBC was 89% after 1, 5, and 10 years and was significantly better than estimated survival without LTx after 1-7 years as calculated by the Mayo and European risk scores. Of several parameters tested, only serum bilirubin and the prognostic scores, but no other liver function tests obtained immediately prior to transplantation were significantly correlated with survival after LTx. The duration of intensive care after LTx was not associated with any parameters obtained before LTx. Bone fractures were diagnosed in 43% of patients of whom the vast majority were osteopenic before LTx as determined by osteodensitometry. Conclusion: Longterm survival of a well-defined group of patients with PBC was excellent after LTx and was inversely correlated with preoperative serum bilirubin levels as well as Mayo and European risk scores. Copyright (C) 2000 S. Karger AG. Basel

Assessing Non-Invasive Liver Function in Patients With Intestinal Failure Receiving Total Parenteral Nutrition-Results From the Prospective PNLiver Trial

Liver abnormalities in intestinal failure (IF) patients receiving parenteral nutrition (PN) can progress undetected by standard laboratory tests to intestinal failure associated liver disease (IFALD). The aim of this longitudinal study is to evaluate the ability of non-invasive liver function tests to assess liver function following the initiation of PN. Twenty adult patients with IF were prospectively included at PN initiation and received scheduled follow-up assessments after 6, 12, and 24 months between 2014 and 2019. Each visit included liver assessment (LiMAx [Liver Maximum Capacity] test, ICG [indocyanine green] test, FibroScan), laboratory tests (standard laboratory test, NAFLD [non-alcoholic fatty liver disease] score, FIB-4 [fibrosis-4] score), nutritional status (bioelectrical impedance analysis, indirect calorimetry), and quality of life assessment. The patients were categorized post-hoc based on their continuous need for PN into a reduced parenteral nutrition (RPN) group and a stable parenteral nutrition (SPN) group. While the SPN group (n = 9) had significantly shorter small bowel length and poorer nutritional status at baseline compared to the RPN group (n = 11), no difference in liver function was observed between the distinct groups. Over time, liver function determined by LiMAx did continuously decrease from baseline to 24 months in the SPN group but remained stable in the RPN group. This decrease in liver function assessed with LiMAx in the SPN group preceded deterioration of all other investigated liver function tests during the study period. Our results suggest that the liver function over time is primarily determined by the degree of intestinal failure. Furthermore, the LiMAx test appeared more sensitive in detecting early changes in liver function in comparison to other liver function tests

Data Preservation at LEP

The four LEP experiments ALEPH, DELPHI, L3 and OPAL successfully recorded e+e- collision data during the years 1989 to 2000. As part of the ordinary evolution in High Energy Physics, these experiments can not be repeated and their data is therefore unique. This article briefly reviews the data preservation efforts undertaken by the four experiments beyond the end of data taking. The current status of the preserved data and associated tools is summarised.Comment: 7 pages, contribution to proceedings of the "First Workshop on Data Preservation and Long Term Analysis in HEP