Equity and ecotax reform in the EU: achieving a 10 per cent reduction in CO2 emissions using excise duties

This paper considers the distributional effects of imposing additional excise duties on energy products according to carbon content. The assumed duties escalate from 1999 to 2010 and achieve levels reducing CO2 emissions by 10 per cent below baseline by 2010 for 11 EU member states. By 2010, real personal disposable incomes are 1.6 per cent above baseline and employment is 1.2 per cent above, assuming that the change is tax-revenue-neutral. The study concludes that the changes will be weakly regressive for nearly all the member states in the study if revenues are used to reduce employers’ taxes and strongly progressive if they are given back lump-sum to households.

Recent advances in understanding mammalian prion structure

Prions are lethal pathogens, which cause fatal neurodegenerative diseases in mammals. They are unique infectious agents and are composed of self-propagating multi-chain assemblies of misfolded host-encoded prion protein (PrP). Understanding prion structure is fundamental to understanding prion disease pathogenesis however to date, the high-resolution structure of authentic ex vivo infectious prions remains unknown. Advances in determining prion structure have been severely impeded by the difficulty in recovering relatively homogeneous prion particles from infected brain and definitively associating infectivity with the PrP assembly state. Recently, however, images of highly infectious ex vivo PrP rods that produce prion-strain specific disease phenotypes in mice have been obtained using cryo-electron microscopy and atomic force microscopy. These images have provided the most detailed description of ex vivo mammalian prions reported to date and have established that prions isolated from multiple strains have a common hierarchical structure. Misfolded PrP is assembled into 20 nm wide rods containing two fibers, each with double helical repeating substructure, separated by a characteristic central gap 8-10 nm in width. Irregularly structured material with adhesive properties distinct to that of the fibers is present within the central gap of the rod. Prions are clearly distinguishable from non-infectious recombinant PrP fibrils generated in vitro and from all other propagating protein structures so far described in other neurodegenerative diseases. The basic architecture of mammalian prions appears to be exceptional and fundamental to their lethal pathogenicity

How Do Minimum Payment Changes Affect Credit Card Arbitrage?

This paper examines how changes in the minimum payment percentage and effective maturity of introductory offers affect credit card arbitrage.  Credit Card arbitrage involves taking a cash advance on, or making purchases against, a credit card that offers a low or zero percent introductory interest rate.  The proceeds are deposited into a Federal Deposit Insurance Corporation (FDIC) insured money market account.  Profits from this strategy are dependent on factors including the minimum payment due on the credit card each month.  Recently, under pressure from the U.S. Office of the Comptroller of the Currency, some banks have increased the minimum monthly payment percentage on their cards.  We measure the sensitivity of Credit Card arbitrage profits to changes in the offer maturity and the required minimum monthly credit card payment.  We also analyze how offer duration changes with changes in the minimum monthly payment.  These calculations represent an important contribution to the literature because of the unique pattern of credit card loan payments

Direct cell-to-cell exchange of matter in synthetic clostridium syntrophies enabling CO2 fixation and an expanded metabolic space.

In microbial fermentations to produce metabolites, at least 33% of the sugar-substrate carbon is lost as CO2 during pyruvate decarboxylation to acetyl-CoA. Previous attempts to reduce this carbon loss focused on engineering a single organism. In nature, microorganisms live in complex communities where syntrophic interactions result in superior resource utilization. Microbial communities are ubiquitous in nature and have a wide range of applications, including production of biofuels and chemicals. Syntrophic and other microbial co-cultures/consortia carry out efficient bio-transformations that are the result of multiple complementary metabolic systems working together. It is now well appreciated that the capabilities of multi-microorganism systems cannot be predicted by the sum of their parts. Rather, synergistic interactions at different levels often result in better overall performance of these systems. Importantly, integration of diverse metabolic systems through syntrophic dependencies make co-culture systems robust to environmental fluctuations. Clostridium organisms are of major importance for developing new technologies to produce biofuels and chemicals. Three major types of Clostridium organisms have been the focus of studies for the sustainable production of fuels and chemicals. Solventogenic clostridia utilize a large variety of biomass-derived carbohydrates (hexoses, pentoses, disaccharides, and hemicellulose), and can produce C2-C4 chemicals. Acetogenic clostridia can fix inorganic H2, CO2, and CO to generate C2 acids and alcohols. Other specialized clostridia possess diverse biosynthetic capabilities for production of a wide variety of metabolites including C4 – C8 carboxylic acids and alcohols, which could serve as commodity chemicals, biofuels, or biofuel precursors. Here, we first examined a synthetic syntrophy consisting of the solventogen Clostridium acetobutylicum, which converts simple and complex carbohydrates into a variety of chemicals, and the acetogen C. ljungdahlii, which fixes CO2. This synthetic co-culture achieved carbon recoveries into C2-C4 alcohols almost to the limit of substrate-electron availability, with minimal H2 and CO2 release. The syntrophic co-culture produced robust metabolic outcomes over a broad range of starting population ratios of the two organisms. Significantly, the co-culture exhibited unique direct cell-to-cell interactions and material exchange among the two microbes, which enabled unforeseen rearrangements in the metabolism of the individual species that resulted in the production of non-native metabolites, namely isopropanol and 2,3-butanediol. Next, we expanded this co-culture system to include C. kluyveri, which can metabolite ethanol and acetate to produce C6 and C8 carboxylic acids. Both C. acetobutylicum and C. ljungdahlii produce ethanol and acetate, which makes C. kluyveri and ideal partner for a triple synthetic co-culture system capable to converting biomass-derived carbohydrates to C6 and C8 chemicals. Supported by the National Science Foundation through the US Army Research Office (ARO; Award No. W911NF-17-1-0343) and the US Department of Energy (DOE; Award No. DE-SC0019155)