Is There a Rationale for Rebating Environmental Levies?

Political pressure often exists for rebating environmental levies, particularly when incomplete regulatory coverage allegedly creates an “unlevel playing field” with other, unregulated firms or industries. This paper assesses the conditions under which rebating environmental levies is justified for the regulated sector. It combines a theoretical approach based on second-best modeling with numerical simulations aimed at determining the most sensitive parameters. We find that if an adequate tax on production can be levied in the unregulated sector, no rebate is justified for the regulated sector. Moreover, even in the case of constrained taxation in the unregulated sector, a tax rebate or a subsidy in the regulated sector is not necessarily a welfare-increasing policy. The exception occurs when the goods of the competing sectors are close substitutes. We find that these kinds of policy contraints can be quite costly in terms of welfare.environmental levy, tax rebate, fiscal distortions

On the usefulness of imprecise Bayesianism in chemical kinetics

International audienceBayesian methods are growing ever more popular in chemical kinetics. The reasons for this and general challenges related to kinetic parameter estimation are shortly reviewed. Most authors content themselves with using one single (mostly uniform) prior distribution. The goal of this paper is to go into some serious issues this raises. The problems of confusing knowledge and ignorance and of reparametrisation are examined. The legitimacy of a probabilistic Ockham’s razor is called into question. A synthetic example involving two reaction models was used to illustrate how merging the parameter space volume with the model accuracy into a single number might be unwise. Robust Bayesian analysis appears to be a simple andstraightforward way to avoid the problems mentioned throughout this article

Biodiesel via in situ wet microalgae biotransformation: Zwitter-type ionic liquid supported extraction and transesterification

The production of biodiesel derived from microalgae is among the most forthcoming technologies that provide an ecologic alternative to fossil fuels. Herein, a method was developed that enables the direct extraction and conversion of algal oil to biodiesel without prior isolation. The reaction occurs in aqueous media catalyzed by immobilized Candida antarctica lipase B (Novozyme 435). Zwitter-type ionic liquids were used as cocatalyst to improve the selectivity and reactivity of the enzyme. In a model reaction with sunflower oil, 64% biodiesel was obtained. Applying this method to a slurry of whole-cell Chlorella zof ingiensis in water resulted in 74.8% of lipid extraction, with 27.7% biotransformation products and up to 16% biodiesel. Factors that reduced the lipase activity with whole-cell algae were subsequently probed and discussed. This "in situ" method shows an improvement to existing methods, since it integrates the oil extraction and conversion into an one-pot procedure in aqueous conditions. The extraction is nondisruptive, and is a model for a greener algae to biodiesel process

Numerical optimisation for model evaluation in combustion kinetics

Numerical optimisation related to the estimation of kinetic parameters and model evaluation is playing an increasing role in combustion as well as in other areas of applied energy research. The present work aims at presenting the current probability-based approaches along applications to real problems of combustion chemical kinetics. The main methods related to model and parameter evaluation have been explicated. An in-house program for the systematic adjustment of kinetic parameters to experimental measurements has been described and numerically validated. The GRI (Gas research institute) mechanism (version 3.0) has been shown to initially lead to results which are greatly at variance with experimental data concerning the combustion of CH3CH3 and C2H6C2H6. A thorough optimisation of all parameters has been performed with respect to these profiles. A considerable improvement could be reached and the new predictions appear to be compatible with the measurement uncertainties. It was also found that neither GRI 3.0 nor three other reaction mechanisms considered during the present work should be employed (without prior far-reaching optimisation) for numerical simulations of combustors and engines where CH3CH3 and C2H6C2H6 play an important role. Overall, this study illustrates the link between optimisation methods and model evaluation in the field of combustion chemical kinetics

First Evaluation of an Index of Low Vagally-Mediated Heart Rate Variability as a Marker of Health Risks in Human Adults: Proof of Concept.

Multiple studies have demonstrated low vagally-mediated heart rate variability (HRV) being associated with a range of risk factors for heart disease and stroke, including inflammation, hyperglycemia, hyperlipidemia, and hypertension. Yet, no cut point exists that indicates elevated risk. In the present study we sought to identify a cut point-value for HRV that is associated with elevated risk across a range of known risk factors. METHODS:A total of 9550 working adults from 19 study sites took part in a health assessment that included measures of inflammation, hyperglycemia, hyperlipidemia, and hypertension and vagally-mediated HRV (Root mean square of successive differences between normal heartbeats (RMSSD)). Multiple age and sex adjusted logistic regressions were calculated per risk factor (normal versus clinical range), with RMSSD being entered in binary at different cut points ranging from 15-39 msec with a 2 msec increment. RESULTS:For daytime RMSSD, values below 25 ± 4 indicated elevated risk (odds ratios (OR) 1.5-3.5 across risk factors). For nighttime RMSSD, values below 29 ± 4 indicated elevated risk (OR 1.2-2.0). CONCLUSION:These results provide the first evidence that a single value of RMSSD may be associated with elevated risk across a range of established cardiovascular risk factors and may present an easy to assess novel marker of cardiovascular risk

Line Extensions erfolgreich managen : welche Faktoren sind kritisch?

Line Extensions stellen eine der wichtigsten produktpolitischen Alternativen von Pharmaunternehmen dar. Im wesentlichen handelt es sich hierbei um die Einführung eines Kombinationspräparates, einer neuen Darreichungsform oder einer neuen Dosierung. Für viele Produktmanager stellt sich die Frage, unter welchen Bedingungen eine Line Extension zu einem Erfolg wird. Einen entscheidenden Einfluß hat die strategische Ausgangssituation, die u.a. durch die Wettbewerbsintensität des avisierten Marktes und die Merkmale der Muttermarke (z.B. Goodwill-Potential) beschrieben wird. Diese Faktoren sind vom Produktmanager nicht zu beeinflussen, können aber in einer langfristig ausgerichteten Programmplanung berücksichtigt werden. Steuerbar sind dagegen die strategischen und operativen Instrumente des Produktmanagements wie die Markierung als strategische Option, die Preisstellung, der Werbedruck oder der Einsatz des Außendiensts. Der wirkungsvolle Einsatz dieser Instrumente steht dabei in engem Zusammenhang mit dem Innovationsgrad der Line Extension und hat somit Konsequenzen für die Beurteilung ihrer Effizienz. Die Autoren untersuchen und diskutieren die Bedingungen erfolgreicher Line Extensions am Beispiel von 64 Neuprodukteinführungen aus drei Produktmärkten und vier europäischen Ländern. Die empirischen Ergebnisse bilden eine verläßliche Grundlage für die Prognose des Erfolgs von Line Extensions anhand ihres erreichbaren Marktanteils

Die simultane Messung von Kannibalisierungs-, substitutiven Konkurrenz- und Neukäuferanteilen am Absatz von line extensions auf der Basis aggregierter Daten

Die Bedeutung von line extensions als produktpolitische Alternative ist nach wie vor ungebrochen. Die Schätzungen ihres Anteils an Neuprodukteinführungen in den Konsumgütermärkten reichen von 80-95%. Ein Problem, das fast immer mit der Einführung einer line extension verbunden sein dürfte, ist das der Kannibalisierung. Aber nicht nur der Umfang der Kannibalisierung ist für die Beurteilung von Produktstrategien von Bedeutung. Der Absatz eines jeden Produktes kann grundsätzlich in die drei Komponenten Kannibalisierung, Wettbewerbssubstitution und Neukäufer aufgespalten werden. Die Autoren stellen eine einfache Methode zur Dekomposition des line extension Absatzes vor. Die einzelnen Absatzkomponenten können mit Least Squares-Methoden empirisch gemessen werden. Eine Anwendung auf line extensions im Pharmamarkt demonstriert das Anwendungspotential des vorgeschlagenen Modells

Joint Antenna Selection and Phase-Only Beamforming Using Mixed-Integer Nonlinear Programming

In this paper, we consider the problem of joint antenna selection and analog beamformer design in downlink single-group multicast networks. Our objective is to reduce the hardware costs by minimizing the number of required phase shifters at the transmitter while fulfilling given distortion limits at the receivers. We formulate the problem as an L0 minimization problem and devise a novel branch-and-cut based algorithm to solve the resulting mixed-integer nonlinear program to optimality. We also propose a suboptimal heuristic algorithm to solve the above problem approximately with a low computational complexity. Computational results illustrate that the solutions produced by the proposed heuristic algorithm are optimal in most cases. The results also indicate that the performance of the optimal methods can be significantly improved by initializing with the result of the suboptimal method.Comment: to be presented at WSA 201

Economic Feasibility of Commercial Algae Oil Production in the United States

A Monte Carlo simulation model was constructed to analyze the economic feasibility of growing algae as a renewable fuel source. Increasing growth rates, pond water depth, oil content, and facility size are important for ensuring the economic viability of a commercial algae facility.algae, renewable, fuel, feedstock, microalgae, Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Production Economics, Resource /Energy Economics and Policy, Risk and Uncertainty,