Can Inheritances Alleviate the Fiscal Burden of an Aging Population?

With pay as you go schemes in place, population aging will impose a heavy fiscal burden on young and future cohorts. However, these cohorts may also profit from larger inheritances as the number of heirs declines. The aim of this paper is to explore the compensating potential of private intergenerational transfers. A dynamic, computable general equilibrium model is employed allowing for a pay as you go scheme, various bequest motives, and an endogenous labor supply. The findings are twofold. First, the increase in future generations' inheritances is insufficient to make up for the demographic burden. Second, increasing the inheritance tax during the demographic transition may alleviate the fiscal burden of future generations by improving overall efficiency. Copyright 2003, International Monetary Fund

Branding in the red meat sector - A conjoint study from Germany

During the last years, low price products (e.g., private label) gain increasing market shares in the German meat market. Compared to other countries the share of branded meat from integrated production chains is very low and most fresh meat is sold unlabelled. This study analyzes the advantages of brands from an information economic perspective and emphasizes branding as an important quality assurance and signaling tool. As brand exte nsions offer the opportunity to introduce brands to new markets at much lower costs we examine the brand transfer from the poultry to the red meat market taking Wiesenhof, the German brand leader for chicken and poultry, as an example. We use conjoint and cluster analysis to calculate willingness to pay and market shares for different consumer segments. The results demonstrate, that branded meat reaches almost two third of market share while the low priced private label always gets the lowest proportions of consumer preferences. Given the choice, customers do not always prefer the cheapest offer but trust in branded meat even more. This market potential is actually not used to advantage. The overall total market share of meat brands lies below 5%.Branding, quality signal, brand extension, meat market, Marketing,

Functional analysis of conserved amino acid residues in the C-terminus of ACC Synthase [abstract]

Abstract only availableEthylene is an important plant hormone that regulates growth, development, and stress response. Synthesis of ethylene from its immediate precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), is catalyzed by ACC oxidase. ACC is produced from S-adenosy1-L-methionine (SAM) in a reaction catalyzed by ACC synthase (ACS). ACS is the rate limiting enzyme of ethylene biosynthesis. Selected isoforms of ACS are substrates of MPK6 and MPK3, the two Arabidopsis stress-responsive mitogen-activated protein kinases (MAPKs). Phosphorylation of ACS6 by MPK6 stabilizes the ACS protein, thus, elevating the levels of cellular ACS activity and ethylene production. Expression of ACS6DDD, a gain-of-function ACS6 mutant that mimics the phosphorylated form of ACS6, shows constitutive ethylene production and ethylene-induced phenotypes. Analysis of Arabidopsis ACS6 and its orthologs from other species in the database revealed conserved charged amino acids (AAs) in addition to the MAPK phosphorylation sites in their C-termini. We hypothesized that these conserved residues may be involved in the regulation of ACS stability. We used site-directed mutagenesis to mutate the conserved charged residues to neutral AAs: Ala, Ile, or Leu in the ACS6WT or ACS6DDD background using the polymerase chain reaction (PCR)-based method. Mutation was confirmed by DNA sequencing. Mutated ACS6 genes were transformed into Arabidopsis plants. The stability of ACS6 protein was tested in vivo to determine if the mutation enhances or diminishes its stability. Ethylene production was used as an output reading and the levels of ACS6 protein were determined by immunoblot analysis. Mutation of positively charged AAs to neutral residues makes the ACS6 protein more stable, whereas the mutation of the negatively charged AAs which are close to the phosphorylation sites destabilizes it. Interestingly, deletion of the C-terminus stabilizes the ACS6 protein, suggesting that C-terminus is required for ACS6 degradation. We observed ethylene-induced phenotypes such as short hairy roots and epinastic leaves in ethylene-overproducing seedlings.Dudley & Virgie Alexander Gif

Querying Proofs (Work in Progress)

We motivate and introduce the basis for a query language designed for inspecting electronic representations of proofs. We argue that there is much to learn from large proofs beyond their validity, and that a dedicated query language can provide a principled way of implementing a family of useful operations

Functional analysis of conserved amino acid residues in the C-terminus of ACC synthase

Abstract only availableEthylene is an important plant hormone that regulates growth, development, and stress response. Synthesis of Ethylene from its immediate precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), is catalyzed by ACC oxidase. ACC is produced from S-Adenosy1-L-Methionine (SAM) in a reaction catalyzed by ACC synthase (ACS). ACS is the rate limiting enzyme of ethylene biosynthesis. Selected isoforms of ACS are substrates of MPK6 and MPK3, the two Arabidopsis stress-responsive mitogen-activated protein kinases (MAPKs). Phosphorylation of ACS6 by MPK6 stabilizes the ACS protein, thus, elevating the levels of cellular ACS activity and ethylene production. Expression of ACS6DDD, a gain-of-function ACS6 mutant that mimics the phosphorylated form of ACS6, shows constitutive ethylene production and ethylene-induced phenotypes. Analysis of Arabidopsis ACS6 and its orthologs from other species in the database revealed conserved charged amino acids (AAs) in addition to the MAPK phosphorylation sites in their C-termini. We hypothesized that these conserved residues may be involved in the regulation of ACS stability. We used site-directed mutagenesis to mutate the conserved residues to Ala, Ile, or Leu in the ACS6WT or ACS6DDD background using the polymerase chain reaction (PCR). Mutation was confirmed by DNA sequencing. ACS6 mutant gene was transformed into Arabidopsis plants. The stability of ACS6 protein was tested in vivo to determine if the mutation enhances or diminishes its stability. Ethylene production was used as an output reading and the levels of ACS6 protein were determined by immunoblot analysis. Mutation of positively charged AAs makes the ACS6 protein more stable, whereas the mutation of the negatively charged AAs which are close to the phosphorylation sites destabilizes it. Interestingly, deletion of the C-terminus stabilizes the ACS6 protein, suggesting that C-terminus is required for ACS6 degradation. We observed ethylene-regulated morphologies like short hairy main roots and epinastic leaves in ethylene-overproducing seedlings.MU Monsanto Undergraduate Research Fellowshi

High-frequency operation of a DC/AC/DC system for HVDC applications

Voltage ratings for HVdc point-to-point connections are not standardized and tend to depend on the latest available cable technology. DC/DC conversion at HV is required for interconnection of such HVdc schemes as well as to interface dc wind farms. Modular multilevel voltage source converters (VSCs), such as the modular multilevel converter (MMC) or the alternate arm converter (AAC), have been shown to incur significantly lower switching losses than previous two- or three-level VSCs. This paper presents a dc/ac/dc system using a transformer coupling two modular multilevel VSCs. In such a system, the capacitors occupy a large fraction of the volume of the cells but a significant reduction in volume can be achieved by raising the ac frequency. Using high frequency can also bring benefits to other passive components such as the transformer but also results in higher switching losses due to the higher number of waveform steps per second. This leads to a tradeoff between volume and losses which has been explored in this study and verified by simulation results with a transistor level model of 30-MW case study. The outcome of the study shows that a frequency of 350 Hz provides a significant improvement in volume but also a penalty in losses compared to 50 Hz

Design and Fabrication of Three-Dimensional Scaffolds for Tissue Engineering of Human Heart Valves

We developed a new fabrication technique for 3-dimensional scaffolds for tissue engineering of human heart valve tissue. A human aortic homograft was scanned with an X-ray computer tomograph. The data derived from the X-ray computed tomogram were processed by a computer-aided design program to reconstruct a human heart valve 3-dimensionally. Based on this stereolithographic model, a silicone valve model resembling a human aortic valve was generated. By taking advantage of the thermoplastic properties of polyglycolic acid as scaffold material, we molded a 3-dimensional scaffold for tissue engineering of human heart valves. The valve scaffold showed a deviation of only +/- 3-4% in height, length and inner diameter compared with the homograft. The newly developed technique allows fabricating custom-made, patient-specific polymeric cardiovascular scaffolds for tissue engineering without requiring any suture materials. Copyright (c) 2008 S. Karger AG, Base