Stops making sense: translational trade-offs and stop codon reassignment

Background Efficient gene expression involves a trade-off between (i) premature termination of protein synthesis; and (ii) readthrough, where the ribosome fails to dissociate at the terminal stop. Sense codons that are similar in sequence to stop codons are more susceptible to nonsense mutation, and are also likely to be more susceptible to transcriptional or translational errors causing premature termination. We therefore expect this trade-off to be influenced by the number of stop codons in the genetic code. Although genetic codes are highly constrained, stop codon number appears to be their most volatile feature. Results In the human genome, codons readily mutable to stops are underrepresented in coding sequences. We construct a simple mathematical model based on the relative likelihoods of premature termination and readthrough. When readthrough occurs, the resultant protein has a tail of amino acid residues incorrectly added to the C-terminus. Our results depend strongly on the number of stop codons in the genetic code. When the code has more stop codons, premature termination is relatively more likely, particularly for longer genes. When the code has fewer stop codons, the length of the tail added by readthrough will, on average, be longer, and thus more deleterious. Comparative analysis of taxa with a range of stop codon numbers suggests that genomes whose code includes more stop codons have shorter coding sequences. Conclusions We suggest that the differing trade-offs presented by alternative genetic codes may result in differences in genome structure. More speculatively, multiple stop codons may mitigate readthrough, counteracting the disadvantage of a higher rate of nonsense mutation. This could help explain the puzzling overrepresentation of stop codons in the canonical genetic code and most variants.

Stress testing credit risk: the Great Depression scenario

By employing Moody’s corporate default and rating transition data spanning the last 90 years we explore how much capital banks should hold against their corporate loan portfolios to withstand historical stress scenarios. Specifically, we will focus on the worst case scenario over the observation period, the Great Depression. We find that migration risk and the length of the investment horizon are critical factors when determining bank capital needs in a crisis. We show that capital may need to rise more than three times when the horizon is increased from 1 year, as required by current and future regulation, to 3 years. Increases are still important but of a lower magnitude when migration risk is introduced in the analysis. Further, we find that the new bank capital requirements under the so-called Basel 3 agreement would enable banks to absorb Great Depression-style losses. But, such losses would dent regulatory capital considerably and far beyond the capital buffers that have been proposed to ensure that banks survive crisis periods without government support.

Mites Parasitic on Australasian and African Spiders Found in the Pet Trade; a Redescription of Ljunghia pulleinei Womersley

Parasitic mites associated with spiders are spreading world-wide through the trade in tarantulas and other pet species. Ljunghia pulleinei Womersley, a mesostigmatic laelapid mite originally found in association with the mygalomorph spider Selenocosmia stirlingi Hogg (Theraphosidae) in Australia, is redescribed and illustrated on the basis of specimens from the African theraphosid spider Pterinochilus chordatus (Gersta¨cker) kept in captivity in the British Isles (Wales). The mite is known from older original descriptions of Womersley in 1956; the subsequent redescription of Domrow in 1975 seems to be questionable in conspecificity of treated specimens with the type material. Some inconsistencies in both descriptions are recognised here as intraspecific variability of the studied specimens. The genus Arachnyssus Ma, with species A. guangxiensis (type) and A. huwenae, is not considered to be a valid genus, and is included in synonymy with Ljunghia Oudemans. A new key to world species of the genus Ljunghia is provided.

Good practice transfer within small construction specialist trade contractors

Government and institutionally-driven ‘good practice transfer’ initiatives are consistently presented as a means to enhance construction firm and industry performance. Two implicit tenets of these initiatives appear to be: knowledge embedded in good practice will transfer automatically; and, the potential of implementing good practice will be capitalised regardless of the context where it is to be used. The validity of these tenets is increasingly being questioned and, concurrently, more nuanced knowledge production understandings are being developed which recognise and incorporate context-specificity. This research contributes to this growing, more critical agenda by examining the actual benefits accrued from good practice transfer from the perspective of a small specialist trade contracting firm. A concept model for successful good practice transfer is developed from a single longitudinal case study within a small heating and plumbing firm. The concept model consists of five key variables: environment, strategy, people, technology, and organisation of work. The key findings challenge the implicit assumptions prevailing in the existing literature and support a contingency approach that argues successful good practice transfer is not just adopting and mechanistically inserting into the firm, but requires addressing ‘behavioural’ aspects. For successful good practice transfer, small specialist trade contracting firms need to develop and operationalise organisation slack, mechanisms for scanning external stimuli and absorbing knowledge. They also need to formulate and communicate client-driven external strategies; to motive and educate people at all levels; to possess internal or accessible complementary skills and knowledge; to have ‘soft focus’ immediate/mid-term benefits at a project level; and, to embed good practice in current work practices.

The information content of REIT credit rating actions and transparency

We examine the short-run and long-run price reaction of equity REIT shares following credit rating actions, testing the transparency of the REIT structure. Generally, the economic effect on the stock price is subdued for both upgrades and downgrades compared to prior literature examining the broader U.S. equity market. An examination of trading volume revealed a significant increase in trading in reaction to downgrade credit rating changes, with a more subdued response to upgrades. The findings support the notion that REITs are more publicly forthcoming about the expectation of positive news in comparison to negative news.

Registering scents as community trade marks

While the registrability of scents as Community trade marks has become source of much controversy, the possibility of trademarking scents represents a great potential for the industry. In the aftermath of the Sieckmann case, which has raised the threshold of registrability for scent marks, companies have refrained from submitting new smell-mark applications. Despite the difficulties in registering scents as trademarks, however, it is not impossible to meet the Sieckmann criteria and file successful scent mark applications. This article explains how this could be possible; it reviews all objections in registering scents as trademarks and brings new light into this topic by way of a comprehensive analysis of the conditions under which scents can be registered as Community trade marks.

The "Fair trade nation": market-oriented development in devolved European regions

Scholars have largely ignored the roles played by government and public sector institutions in the fair trade movement. This article addresses the knowledge gap through examining government involvement in fair trade networks in the context of European devolution and the localization of international development action. Proposing a relational view of fair trade networks, and considering the Fair Trade Nation as a social category for development, it highlights how power sources outside the centralized nation-state permit a political community to associate itself with fair trade. Research from Wales demonstrates that government acts in a leadership role rather than as regulator, conferring political voice and finance while enhancing its international credentials and contributing to the politics of nation-building. Our conclusion is cautious; campaigners celebrate political commitment to fair trade embodied within the category of the Fair Trade Nation, but evidence suggests that government reliance on the market as a vehicle for decentralized development action is limited by how the Fair Trade Nation is currently executed.

Reframing 'crisis' in fair trade coffee production: trajectories of agrarian change in Nicaragua

A focus on crisis provides a methodological window to understand how agrarian change shapes producer engagement in fair trade. This orientation challenges a seperation between the market and development, situating fair trade within global processes that incorporate agrarian histories of social change and conflict. Reframing crisis as a condition of agrarian life, rather than emphasizing its cyclical manifestation within the global economy, reveals how market-driven development encompasses the material conditions of peoples' existence in ambiguous and contradictory ways. Drawing on the case of coffee production in Nicaragua, experiences of crisis demonstrate that greater attention needs to be paid to the socioeconomic and political dimensions of development within regional commodity assemblages to address entrenched power relations and unequal access to land and resources. This questions moral certainties when examining the paradox of working in and against the market, and suggests that a better understanding of specific trajectories of development could improve fair trade's objective of enhancing producer livelihoods.