Liquidity and Competition in Unregulated Markets

Despite reputedly widespread market manipulation and insider trading, we find surprisingly high liquidity and low transactions costs for actively traded securities on the NYSE between 1890 and 1910, decades before SEC regulation. Moreover, market makers behave largely as predicted in theory: stocks with liquid markets and competitive market makers (cross-trading at the rival Consolidated Exchange) trade with substantially lower quoted bid-ask spreads and with less anti-competitive behavior (price discreteness). Effective spreads, illiquidity, and volume all improve monotonically over time. Notably, the asymmetric information component of effective spreads increases in relative and absolute terms from 1900 to 1910.

I want to know: Willingness to pay for unconditional veto power

Abstract In the Yes/No game, like in the ultimatum game, proposer and responder can share a monetary reward. In both games the proposer suggests a reward distribution which the responder can accept or reject (yielding 0-payoffs). The games only differ in that the responder does (not) learn the suggested reward distribution in the Ultimatum (Yes/No) game. Although an opportunistic responder would always accept and therefore should not be willing to pay for knowing the proposal, earlier results (Güth, PsycINFO classification: 3020 JEL classification: D82, C9

Soziale Kosten des Glücksspiels in Casinos: Studie zur Erfassung der durch die Schweizer Casinos verursachten sozialen Kosten

"Nach Inkrafttreten des neuen Spielbankengesetzes im April 2000 veränderte sich die Glücksspiel- bzw. Casinolandschaft in der Schweiz grundlegend. Seit 2003 stehen dauerhaft 19 Casinos in Betrieb, deren Nutzung über die Jahre stetig zugenommen hat. Im Jahr 2008 erreichte der Bruttospielertrag der Casinos rund 992 Mio. Fr. Die Spielbankenabgabe zuhanden der AHV und der Standortkantone der B-Casinos betrug 517 Mio. Fanken. Einer der Hauptvorbehalte gegen die Zulassung von Spielbanken war und ist die vermutete Zunahme von Glücksspielsucht mit ihren gesellschaftlich und wirtschaftlich negativen Auswirkungen. Um zu beurteilen, ob die Anforderungen im Bereich des Sozialschutzes innerhalb der Casinos ausreichend sind, hat die ESBK u.a. eine Studie zu den durch die Eröffnung der Casinos verursachten sozialen Kosten in Auftrag gegeben. Mit der Erarbeitung der Studie wurde das Büro für arbeits- und sozialpolitische Studien (BASS) beauftragt. Die forschungsleitenden Fragen wurden von der ESBK vorgegeben: Wie hoch sind die gesellschaftlich zu tragenden Kosten? Wer finanziert/trägt die Kosten, wer verursacht sie? Welche Aussagen lassen sich zur Entwicklung der Kostensituation machen? Wie lässt sich die Kostensituation im Vergleich einschätzen? Welche Aussagen lassen sich über die Wirksamkeit der Sozialkonzepte machen?(...)" (Autorenreferat

Challenges and pitfalls of experimental bariatric procedures in rats

Introduction: The impact of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on obesity and obesity-related diseases is unquestionable. Up to now, the technical descriptions of these techniques in animals/rats have not been very comprehensive. Methods: For SG and RYGB, operating time, learning curve, and intraoperative mortality in relation to weight of the rat and type of anesthesia were recorded. Furthermore, a review of the literature on experimental approaches towards SG and RYGB in rats was carried out, merging in a detailed technical description for both procedures. Results: The data presented here revealed that the mean operating time for SG (69.4 +/- 22.2 min (SD)) was shorter than for RYGB (123.0 +/- 20.7 min). There is a learning curve for both procedures, resulting in a reduced operating time of up to 60% in SG and 35% in RYGB (p < 0.05; t-test). However, with increased weight, operating time increases to about 80 min for SG and about 120 min for RYGB. Obese rats have an increased intraoperative mortality rate of up to 50%. After gaseous anesthesia the mortality can be even higher. The literature search revealed 40 papers dealing with SG and RYGB in rats. 18 articles (45%) contained neither photographs nor illustrations; 14 articles (35%) did not mention the applied type of anesthesia. The mortality rate was described in 15 papers (37.5%). Conclusion: Experimental obesity surgery in rats is challenging. Because of the high mortality in obese rats operated under gaseous anesthesia, exercises to establish the techniques should be performed in small rats using intraperitoneal anesthesia. Copyright (C) 2012 S. Karger GmbH, Freibur

LigaSure Impact™ versus conventional dissection technique in pylorus-preserving pancreatoduodenectomy in clinical suspicion of cancerous tumours on the head of the pancreas: study protocol for a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>The pp-Whipple procedure requires extensive preparation. The conventional preparation technique is done with scissors for dissection and ligatures, and with clips and sutures for hemostasis. This procedure is very time-consuming and requires numerous changes of instruments. The LigaSure™ device allows dissection and hemostasis for preparation with one instrument. Up to now there has been no comparison of the two techniques with regard to operating time and the patients' outcome. It is still unclear which technique has the optimal benefit/risk ratio for the patient.</p> <p>Methods/Design</p> <p>A single-center, randomized, single-blinded, controlled superiority trial to compare two different techniques for dissection in a pp-Whipple procedure. 102 patients will be included and randomized pre-operatively. All patients aged 18 years or older scheduled for primary elective pp-Whipple procedure who signed the informed consent will be included. The primary endpoint is the operating time of the randomized technique. Control Intervention: Conventional dissection technique; experimental intervention: LigaSureTM dissection technique. Duration of study: Approximately 15 months; follow up time: 3 years. The trial is registered at German ClinicalTrials Register (DRKS00000166).</p

Minimum Mutual Information Beamforming for Simultaneous Active Speakers

In this work, we consider an acoustic beamforming application where two speakers are simultaneously active. We construct one subband-domain beamformer in \emph{generalized sidelobe canceller} (GSC) configuration for each source. In contrast to normal practice, we then jointly optimize the \emph{active weight vectors} of both GSCs to obtain two output signals with \emph{minimum mutual information} (MMI). Assuming that the subband snapshots are Gaussian-distributed, this MMI criterion reduces to the requirement that the \emph{cross-correlation coefficient} of the subband outputs of the two GSCs vanishes. We also compare separation performance under the Gaussian assumption with that obtained from several super-Gaussian probability density functions (pdfs), namely, the Laplace, $K_0$, and $\Gamma$ pdfs. Our proposed technique provides effective nulling of the undesired source, but without the signal cancellation problems seen in conventional beamforming. Moreover, our technique does not suffer from the source permutation and scaling ambiguities encountered in conventional blind source separation algorithms. We demonstrate the effectiveness of our proposed technique through a series of far-field automatic speech recognition experiments on data from the \emph{PASCAL Speech Separation Challenge} (SSC). On the SSC development data, the simple delay-and-sum beamformer achieves a word error rate (WER) of 70.4\%. The MMI beamformer under a Gaussian assumption achieves a 55.2\% WER, which is further reduced to 52.0\% with a $K_0$ pdf, whereas the WER for data recorded with a close-talking microphone is 21.6\%

Laparoscopic mesh-augmented hiatoplasty without fundoplication as a method to treat large hiatal hernias

PURPOSE: Laparoscopic hiatal hernia repair with additional fundoplication is a commonly recommended standard surgical treatment for symptomatic large hiatal hernias with paraesophageal involvement (PEH). However, due to the risk of persistent side effects, this method remains controversial. Laparoscopic mesh-augmented hiatoplasty without fundoplication (LMAH), which combines hiatal repair and mesh reinforcement, might therefore be an alternative. METHODS: In this retrospective study of 55 (25 male, 30 female) consecutive PEH patients, the perioperative course and symptomatic outcomes were analyzed after a mean follow-up of 72 months. RESULTS: The mean DeMeester symptom score decreased from 5.1 to 1.8 (P < 0.001) and the gas bloating value decreased from 1.2 to 0.5 (P = 0.001). The dysphagia value was 0.7 before surgery and 0.6 (P = 0.379) after surgery. The majority of the patients were able to belch and vomit (96 and 92 %, respectively). Acid-suppressive therapy on a regular basis was discontinued in 68 % of patients. In 4 % of patients, reoperation was necessary due to recurrent or persistent reflux. A mesh-related stenosis that required endoscopic dilatation occurred in 2 % of patients. CONCLUSIONS: LMAH is feasible, safe and provides an anti-reflux effect, even without fundoplication. As operation-related side effects seem to be rare, LMAH is a potential treatment option for large hiatal hernias with paraesophageal involvement