University of Mannheim

About: University of Mannheim is a education organization based out in Mannheim, Germany. It is known for research contribution in the topics: Context (language use) & Politics. The organization has 4448 authors who have published 12918 publications receiving 446557 citations. The organization is also known as: Uni Mannheim & UMA.

Sulfur availability regulates plant growth via glucose-TOR signaling.

Abstract: Growth of eukaryotic cells is regulated by the target of rapamycin (TOR). The strongest activator of TOR in metazoa is amino acid availability. The established transducers of amino acid sensing to TOR in metazoa are absent in plants. Hence, a fundamental question is how amino acid sensing is achieved in photo-autotrophic organisms. Here we demonstrate that the plant Arabidopsis does not sense the sulfur-containing amino acid cysteine itself, but its biosynthetic precursors. We identify the kinase GCN2 as a sensor of the carbon/nitrogen precursor availability, whereas limitation of the sulfur precursor is transduced to TOR by downregulation of glucose metabolism. The downregulated TOR activity caused decreased translation, lowered meristematic activity, and elevated autophagy. Our results uncover a plant-specific adaptation of TOR function. In concert with GCN2, TOR allows photo-autotrophic eukaryotes to coordinate the fluxes of carbon, nitrogen, and sulfur for efficient cysteine biosynthesis under varying external nutrient supply.

The impact of a carbon tax on manufacturing: evidence from microdata

Abstract: We estimate the impact of a carbon tax on manufacturing plants using panel data from the UK production census. Our identification strategy builds on the comparison of outcomes between plants subject to the full tax and plants that paid only 20% of the tax. Exploiting exogenous variation in eligibility for the tax discount, we find that the carbon tax had a strong negative impact on energy intensity and electricity use. There is no evidence of an adverse impact on employment, revenue or plant exit.

An Economist's Guide to Digital Music

Abstract: In this guide, we discuss the impact of digitalization on the music industry. We rely on market and survey data at the international level as well as expert statements from the industry. The guide investigates recent developments in legal and technological protection of digital music and describes new business models as well as consumers' attitude towards music downloads and audio-streaming. We conclude the guide by a discussion of the evolution of the music industry.

Measuring and Managing Consumer Sentiment in an Online Community Environment

Abstract: As social media and virtual communities increase in popularity, the spread of word of mouth becomes easier, challenging firms to measure and manage the success of marketing initiatives in online community environments. This research examines how consumers react to firms' active participation in consumer-to-consumer conversations in an online community setting. The authors develop a tailored community-matched measure of consumer reaction (consumer sentiment) and analyze more than 115,000 consumer posts from ten online forums with active firm participation. The results indicate that consumers show diminishing returns to active firm engagement, which, at very high levels, can undermine consumer sentiment. Further subgroup analyses by conversation type indicate that these relationships hold for conversations that address consumers' functional needs but do not hold for conversations that address social needs. Finally, the results show diminishing returns to firm engagement for consumers primarily interested in...

A note on fast Fourier transforms for nonequispaced grids

Abstract: In this paper, we are concerned with fast Fourier transforms for nonequispaced grids. We propose a general efficient method for the fast evaluation of trigonometric polynomials at nonequispaced nodes based on the approximation of the polynomials by special linear combinations of translates of suitable functions ϕ. We derive estimates for the approximation error. In particular, we improve the estimates given by Dutt and Rokhlin [7]. As a practical consequence, we obtain a criterion for the choice of the parameters involved in the fast transforms.