Exclusive Dealing

In this paper, we provide a conceptual framework for understanding the phenomenon of exclusive dealing, and we explore the motivations for and effects of its use. For a broad class of models, we characterize the outcome of a contracting game in which manufacturers may employ exclusive dealing provisions in their contracts. We then apply this characterization to a sequence of specialized settings. We demonstrate that exclusionary contractual provisions may be irrelevant, anticompetitive, or efficiency-enhancing, depending upon the setting. More specifically, we exhibit the potential for anticompetitive effects in non-coincident markets (that is, markets other than the ones in which exclusive dealing is practiced), and we explore the potential for the enhancement of efficiency in a setting where common representation gives rise to incentive conflicts. In each instance, we describe the manner in which equilibrium outcomes would be altered by a ban on exclusive dealing. We demonstrate that a ban may have surprisingly subtle and unintended effects.

Load fluctuations drive actin network growth

The growth of actin filament networks is a fundamental biological process that drives a variety of cellular and intracellular motions. During motility, eukaryotic cells and intracellular pathogens are propelled by actin networks organized by nucleation-promoting factors, which trigger the formation of nascent filaments off the side of existing filaments in the network. A Brownian ratchet (BR) mechanism has been proposed to couple actin polymerization to cellular movements, whereby thermal motions are rectified by the addition of actin monomers at the end of growing filaments. Here, by following actin--propelled microspheres using three--dimensional laser tracking, we find that beads adhered to the growing network move via an object--fluctuating BR. Velocity varies with the amplitude of thermal fluctuation and inversely with viscosity as predicted for a BR. In addition, motion is saltatory with a broad distribution of step sizes that is correlated in time. These data point to a model in which thermal fluctuations of the microsphere or entire actin network, and not individual filaments, govern motility. This conclusion is supported by Monte Carlo simulations of an adhesion--based BR and suggests an important role for membrane tension in the control of actin--based cellular protrusions.Comment: To be published in PNA

Somatostatin treatment attenuates proteinuria and prevents weight loss in NZB/W F1 mice

Somatostatin, a naturally occurring neuropeptide, is an immunomodulator which inhibits humoral and cell mediated immunity as well as secretion of proinflammatory cytokines. The objective of this study was to examine the effects of a somatostatin analogue on the severity of glomerulonephritis in the female NZB/W F1 murine model of systemic lupus erythematosus (SLE). Twenty female NZB/W F1 mice were treated at 23 weeks of age with 10 mg/kg of the somatostatin analogue Sandostatin-LAR, IM every four weeks. Ten control mice received IM injection of vehicle. Mice were assessed at fourweek intervals for weight change, proteinuria, anti-DNA antibodies and splenocyte cytokine profile. The mice were sacrificed at age 34.5 weeks. Kidneys were collected and evaluated by light and immunofluorescence (IF) microscopy. Spleens were collected and splenocyte intracellular cytokines were measured by FACS analysis. In the treatment group significantly less proteinuria was observed four weeks after the second somatostatin analogue injection (dipstik scale: ϩ2.07 Ϯ 0.95 versus. ϩ3.5 Ϯ 1.08, P ϭ 0.0002). The treated mice did not lose weight while the control group lost weight over time (P ϭ 0.016). No differences were noted between the groups in anti-DNA antibody titres, cytokine profile or the severity of lupus nephritis as assessed by light and IF microscopy. Somatostatin analogue treatment attenuated proteinuria and prevented weight loss in NZB/W F1 mice, suggesting a possible beneficial effect on renal parameters and systemic manifestations of the disease. Further studies will be needed to assess the value of somatostatin analogue treatment in lupus nephritis, utilizing higher doses, at different stages of the disease, for longer periods. Lupus (2006) 15, 526-531

Consumer confidence indices and stock markets’ meltdowns

Consumer confidence indices (CCIs) are a closely monitored barometer of countries’ economic health and an informative forecasting tool. Using European and US data, we provide a case study of the two recent stock market meltdowns (the post-dotcom bubble correction of 2000–2002 and the 2007–2009 decline at the beginning of the financial crisis) to contribute to the discussion on their appropriateness as proxies for stock markets’ investor sentiment. Investor sentiment should positively covary with stock market movements (DeLong, Shleifer, Summers, and Waldmann 1990); however, we find that the CCI–stock market relationship is not universally positive.We also do not find support for the information effect documented in the previous literature, but identify a more subtle relationship between consumer expectations about future household finances and stock market fluctuations

Proof-theoretic Analysis of Rationality for Strategic Games with Arbitrary Strategy Sets

In the context of strategic games, we provide an axiomatic proof of the statement Common knowledge of rationality implies that the players will choose only strategies that survive the iterated elimination of strictly dominated strategies. Rationality here means playing only strategies one believes to be best responses. This involves looking at two formal languages. One is first-order, and is used to formalise optimality conditions, like avoiding strictly dominated strategies, or playing a best response. The other is a modal fixpoint language with expressions for optimality, rationality and belief. Fixpoints are used to form expressions for common belief and for iterated elimination of non-optimal strategies.Comment: 16 pages, Proc. 11th International Workshop on Computational Logic in Multi-Agent Systems (CLIMA XI). To appea

Different effects of sevoflurane, desflurane, and isoflurane on early and late left ventricular diastolic function in young healthy adults†

Background Knowledge on the effects of volatile anaesthetics on left ventricular (LV) diastolic function in humans in vivo is limited. We tested the hypothesis that sevoflurane, desflurane, and isoflurane do not impair LV diastolic function in young healthy humans. Methods Sixty otherwise healthy subjects (aged 18-48 yr) undergoing minor procedures under general anaesthesia were studied. After randomization for the anaesthetic, transthoracic echocardiographic examinations were performed at baseline and under anaesthesia with 1 minimum alveolar concentration (MAC) of the volatile anaesthetics during spontaneous breathing and intermittent positive pressure ventilation (IPPV). Peak early (E′) and late (A′) diastolic velocities of the mitral annulus were studied as the main echocardiographic indicators of diastolic function. Results During anaesthesia with 1 MAC under spontaneous breathing, E′ increased with desflurane (P<0.001), was not significantly different with isoflurane (P=0.030), and decreased with sevoflurane (P=0.006). During IPPV, E′ was similar to baseline with desflurane (P=0.550), insignificantly decreased with isoflurane (P=0.029), and decreased with the sevoflurane group (P<0.001). In contrast, A′ was similarly reduced in all groups during spontaneous breathing without further changes during IPPV. Haemodynamic changes were comparable in all study groups. Conclusions The findings of this in vivo study indicate that desflurane and isoflurane, and most likely sevoflurane, have no relevant direct negative effect on early diastolic relaxation in young healthy humans. In contrast, all three volatile anaesthetics appear to impair late diastolic LV filling during atrial contraction. Trial Registration #: NCT002445

To Ban or Not to Ban: Foreign Lobbying and Cross National Externalities

This paper studies the costs and benefits of foreign lobbying. We show how and when foreign lobbying can help internalize cross national externalities. We argue that this is an often overlooked benefit of foreign lobbying. We also study under what conditions a constitutional rule banning foreign lobbying is in the national interest of a country. A key factor in this calculus is whether the interests of foreign lobby groups and domestic unorganized groups coincide or not. We illustrate the logic with examples from trade policy and environmental regulation