Dynamic Duopoly with Intertemporal Capacity Constraints

We analyze strategic firm behavior in settings where the production stage is followed by several periods during which only sales take place. We analyze the dynamics of the market structure, the development of prices and sales over time, and the implications for profits and consumer surplus. Two specific settings are analyzed. In the first, a firm can commit up-front to a sales strategy that does not depend on the actual sales of its competitor. In this case there is a unique Nash equilibrium and price increases over time. In the second setting,there is no commitment and firms can adjust their sales in response to observed supply of their competitor in the previous period. It is shown that in this case a subgame perfect Nash equilibrium does not always exist. Equilibria can have surprising features. For some parameter constellations, price may decrease over time. It is also possible that the firm increases its pro�t by destroying some of its production. When firms have equal size, the equilibrium outcome is the same in both the commitment and the non-commitment setting. In general, the setting without commitment is bene�cial to the larger firm, whereas the setting with commitment leads to higher pro�ts for the smaller firm.mathematical economics;

Distribution and thickness of the surface contaminations on STM tungsten tips, studied by AES/SEM and ARXPS

The combination of Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and angle resolved X-ray photoelectron spectroscopy (ARXPS) has been applied to the analysis of the distribution of elements at the surface region of electrochemically etched tungsten tips and the determination of the thickness of a layer with oxygen and carbon contamination. Auger line profiling revealed a homogeneous distribution of oxygen and significant enrichment of carbon on the W tip between 0 and 1.5 μm from the top. The thickness of the contamination layer on various W materials, electrochemically etched, was found to be 1.35±0.15 nm as measured using ARXPS, and was estimated to be about 1–3 nm as measured by AES

Intraguild predation behaviour of ladybirds in semi-field experiments explains invasion success of Harmonia axyridis

Harmonia axyridis has been introduced as a biological control agent in Europe and the USA. Since its introduction, it has established and spread, and it is now regarded as an invasive alien species. It has been suggested that intraguild predation is especially important for the invasion success of H. axyridis. The aim of this study was to compare the intraguild predation behaviour of three ladybird species (Coccinella septempunctata, Adalia bipunctata, and H. axyridis). Predation behaviour was investigated in semi-field experiments on small lime trees (Tilia platyphyllos). Two fourth-instar larvae placed on a tree rarely made contact during 3-hour observations. When placed together on a single leaf in 23%–43% of the observations at least one contact was made. Of those contacts 0%–27% resulted in an attack. Harmonia axyridis attacked mostly heterospecifics, while A. bipunctata and C. septempunctata attacked heterospecifics as often as conspecifics. In comparison with A. bipunctata and C. septempunctata, H. axyridis was the most successful intraguild predator as it won 86% and 44% of heterospecific battles against A. bipunctata and C. septempunctata respectively, whilst A. bipunctata won none of the heterospecific battles and C. septempunctata won only the heterospecific battles against A. bipunctata. Coccinella septempunctata dropped from a leaf earlier and more often than the other two species but was in some cases able to return to the tree, especially under cloudy conditions. The frequency with which a species dropped did not depend on the species the larva was paired with. The results of these semi-field experiments confirm that H. axyridis is a strong intraguild predator as a consequence of its aggressiveness and good defence against predation from heterospecific species. The fact that H. axyridis is such a strong intraguild predator helps to explain its successful establishment as invasive alien species in Europe and the USA

Health-related quality of life and cardiac rehabilitation: Does body mass index matter?

OBJECTIVE: To investigate the relation between body mass index class and changes in health-related quality of life in patients participating in cardiac rehabilitation. DESIGN: Prospective cohort study. PATIENTS: A total of 503 patients with acute coronary syndrome. METHODS: Data from the OPTICARE trial were used, in which health-related quality of life was measured with the MacNew Heart Disease HRQOL Instrument at the start, directly after, and 9 months after completion of cardiac rehabilitation. Patients were classed as normal weight, overweight, or obese. RESULTS: During cardiac rehabilitation, global health-related quality of life improved in patients in all classes of body mass index. Patients classed as overweight had a significantly greater improvement in social participation than those classed as normal weight (5.51-6.02 compared with 5.73-5.93, respectively; difference in change 0.30, p = 0.025). After completion of cardiac rehabilitation, health-related quality of life continued to improve similarly in patients in all classes of body mass index. CONCLUSION: Health-related quality of life improved during cardiac rehabilitation in patients of all classes of body mass index. Patients classed as overweight showed the greatest improvement. The beneficial effects were maintained during extended follow-up after completion of cardiac rehabilitation

Validation of automatic measurement of QT interval variability

Background Increased variability of beat-to-beat QT-interval durations on the electrocardiogram (ECG) has been associated with increased risk for fatal and non-fatal cardiac events. However, techniques for the measurement of QT variability (QTV) have not been validated since a gold standard is not available. In this study, we propose a validation method and illustrate its use for the validation of two automatic QTV measurement techniques. Methods Our method generates artificial standard 12-lead ECGs based on the averaged P-QRS-T complexes from a variety of existing ECG signals, with simulated intrinsic (QT interval) and extrinsic (noise, baseline wander, signal length) variations. We quantified QTV by a commonly used measure, short-term QT variability (STV). Using 28,800 simulated ECGs, we assessed the performance of a conventional QTV measurement algorithm, resembling a manual QTV measurement approach, and a more advanced algorithm based on fiducial segment averaging (FSA). Results The results for the conventional algorithm show considerable median absolute differences between the simulated and estimated STV. For the highest noise level, median differences were 4±6 ms in the absence of QTV. Increasing signal length generally yields more accurate STV estimates, but the difference in performance between 30 or 60 beats is small. The FSA algorithm proved to be very accurate, with most median absolute differences less than 0.5 ms, even for the highest levels of disturbance. Conclusions Artificially constructed ECGs with a variety of disturbances allow validation of QTV measurement procedures. The FSA algorithm provides highly accurate STV estimates under varying signal conditions, and performs much better than traditional beat-by-beat analysis. The fully automatic operation of the FSA algorithm enables STV measurement in large sets of ECGs

Polarization Correlations of 1S0 Proton Pairs as Tests of Bell and Wigner Inequalities

In an experiment designed to overcome the loophole of observer dependent reality and satisfying the counterfactuality condition, we measured polarization correlations of 1S0 proton pairs produced in 12C(d,2He) and 1H(d,He) reactions in one setting. The results of these measurements are used to test the Bell and Wigner inequalties against the predictions of quantum mechanics.Comment: 8 pages, 4 figure

Inactive and sedentary lifestyles amongst ambulatory adolescents and young adults with cerebral palsy

Background: To assess physical behaviour, including physical activity and sedentary behaviour, of ambulatory adolescents and young adults with cerebral palsy (CP). We compared participant physical behaviour to that of able-bodied persons and assessed differences related to Gross Motor Functioning Classification System (GMFCS) level and CP distribution (unilateral/bilateral). Methods. In 48 ambulatory persons aged 16 to 24 years with spastic CP and in 32 able-bodied controls, physical behaviour was objectively determined with an accelerometer-based activity monitor. Total duration, intensity and type of physical activity were assessed and sedentary time was determined (lying and sitting). Furthermore, distribution of walking bouts and sitting bouts was specified. Results: Adolescents and young adults with CP spent 8.6% of 24 hours physically active and 79.5% sedentary, corresponding with respectively 123 minutes and 1147 minutes per 24 hours. Compared to able-bodie

A study of the dopamine transporter using the TRACT assay, a novel in vitro tool for solute carrier drug discovery

Members of the solute carrier (SLC) transporter protein family are increasingly recognized as therapeutic drug targets. The majority of drug screening assays for SLCs are based on the uptake of radiolabeled or fluorescent substrates. Thus, these approaches often have limitations that compromise on throughput or the physiological environment of the SLC. In this study, we report a novel application of an impedance-based biosensor, xCELLigence, to investigate dopamine transporter (DAT) activity via substrate-induced activation of G protein-coupled receptors (GPCRs). The resulting assay, which is coined the 'transporter activity through receptor activation' (TRACT) assay, is based on the hypothesis that DAT-mediated removal of extracellular dopamine directly affects the ability of dopamine to activate cognate membrane-bound GPCRs. In two human cell lines with heterologous DAT expression, dopamine-induced GPCR signaling was attenuated. Pharmacological inhibition or the absence of DAT restored the apparent potency of dopamine for GPCR activation. The inhibitory potencies for DAT inhibitors GBR12909 (pIC50 = 6.2, 6.6) and cocaine (pIC50 = 6.3) were in line with values from reported orthogonal transport assays. Conclusively, this study demonstrates the novel use of label-free whole-cell biosensors to investigate DAT activity using GPCR activation as a readout. This holds promise for other SLCs that share their substrate with a GPCR.Medicinal Chemistr