Fourteen years of R/qtl: Just barely sustainable

R/qtl is an R package for mapping quantitative trait loci (genetic loci that contribute to variation in quantitative traits) in experimental crosses. Its development began in 2000. There have been 38 software releases since 2001. The latest release contains 35k lines of R code and 24k lines of C code, plus 15k lines of code for the documentation. Challenges in the development and maintenance of the software are discussed. A key to the success of R/qtl is that it remains a central tool for the chief developer's own research work, and so its maintenance is of selfish importance.Comment: Previously submission to First Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE), http://wssspe.researchcomputing.org.uk; revised for submission to the Journal of Open Research Software, http://openresearchsoftware.metajnl.com

STRATEGIC MANAGEMENT OF GENERAL MERCHANDISE

Agribusiness,

The impact of mass extinctions

In the years since Snowbird an explosive growth of research on the patterns, causes, and consequences of extinction was seen. The fossil record of extinction is better known, stratigraphic sections were scrutinized in great detail, and additional markers of environmental change were discovered in the rock record. However flawed, the fossil record is the only record that exists of natural extinction. Compilations from the primary literature contain a faint periodic signal: the extinctions of the past 250 my may be regulary spaced. The reality of the periodicity remains a subject for debate. The implications of periodicity are so profound that the debate is sure to continue. The greater precision from stratigraphic sections spanning extinction events has yet to resolve controversies concerning the rates at which extinctions occurred. Some sections seem to record sudden terminations, while others suggest gradual or steplike environmental deterioration. Unfortunately, the manner in which the strata record extinctions and compile stratigraphic ranges makes a strictly literal reading of the fossil record inadvisable. Much progress was made in the study of mass extinctions. The issues are more sharply defined but they are not fully resolved. Scenarios should look back to the phenomena they purport to explain - not just an iridium-rich layer, but the complex fabric of a mass extinction

Solar thermal energy receiver

A plurality of heat pipes in a shell receive concentrated solar energy and transfer the energy to a heat activated system. To provide for even distribution of the energy despite uneven impingement of solar energy on the heat pipes, absence of solar energy at times, or failure of one or more of the heat pipes, energy storage means are disposed on the heat pipes which extend through a heat pipe thermal coupling means into the heat activated device. To enhance energy transfer to the heat activated device, the heat pipe coupling cavity means may be provided with extensions into the device. For use with a Stirling engine having passages for working gas, heat transfer members may be positioned to contact the gas and the heat pipes. The shell may be divided into sections by transverse walls. To prevent cavity working fluid from collecting in the extensions, a porous body is positioned in the cavity

The Lewis Heat Pipe Code with Application to SP-100 GES Heat Pipes

The NASA Lewis Research Center has a thermal management program supporting SP-100 goals, which includes heat pipe radiator development. As a part of the program Lewis has elected to prepare an in-house heat pipe code tailored to the needs of its SP-100 staff to supplement codes from other sources. The latter, designed to meet the needs of the originating organizations, were deemed not entirely appropriate for use at Lewis. However, a review of their features proved most beneficial in the design of the Lewis code

Oil Price Indexing Of Natural Gas Prices: An Economic Analysis

Oil price indexing is a peculiar feature of the natural gas markets in Germany and other European countries. It is closely linked to the existence of local monopolies (at least de facto) and of the so called "take-or-pay" (TOP) contracts. After discussing the relation between these features and the motivations for oil price indexing, we formally analyze this strategy in a differentiated good oligoply with a monopolistic supplier of natural gas and competing oil distributors. Starting with a symmetric setting, we first point out how oil price indexing works as a collusive device. In a second step we account for the likely asymmetries between oil and gas distributors. We show that the result obtained under symmetry is not robust and we discuss how the impact of oil price indexing on prices, profits and welfare depends on the form and extent of the asymmetries. -- Die Ölpreisbindung des Erdgaspreises ist ein hervorstechendes Merkmal des Gasmarktes in Deutschland und anderen europäischen Ländern. Diese Besonderheit ist eng verknüpft mit der Existenz lokaler Monopole (trotz Liberalisierung bestehen diese bislang zumindest in Deutschland de facto weiterhin) und sogenannter "take-or-pay" Verträge (TOP contracts), d. h. fixer Abnahmeverpflichtungen zu einem an die Entwicklung des Ölpreises gekoppelten Abnahmepreises. Nach einer Diskussion der Beziehung zwischen diesen drei Besonderheiten des Erdgasmarktes und der möglichen Gründe für die Ölpreisbindung analysieren wir diese Strategie in einem Oligopolmodell mit differenzierten Produkten mit einem monopolistischen Erdgasanbieter und einem oder mehreren konkurrierenden Ölhändlern. Zunächst zeigen wir im Rahmen einer symmetrischen Spezifikation auf, wie die Ölpreisbindung die Kollusion zwischen Erdgas? und Ölanbietern ermöglicht. Anschließend berücksichtigen wir mögliche Asymmetrien zwischen den beiden Energieformen. Dabei zeigt sich, dass das Ergebnis bei Symmetrie nicht robust ist und wir diskutieren im Detail wie die Auswirkung der Ölpreisbindung auf Preise, Gewinne und Wohlfahrt von der Art und vom Ausmaß der Asymmetrien abhängt.Natural gas market,Oligopoly,oil price indexing,Take-or-pay contracts

Car Road Charging: Impact Assessment on German and Austrian Households

The authors apply a computable general equilibrium (CGE) modeling framework to carry out a two-country comparison for Austria and Germany assessing the impact of road charging (RC). The pricing policy measure is introduced for the private motorized transport mode and applies to the overall road network. To derive and compare distributional effects of passenger car RC, the mode-specific travel demand of private households is integrated into the CGE model. Furthermore, the modeling framework accounts for different household categories with respect to disposable net income and the corresponding travel demand profiles introduced in terms of behavioral mobility parameters as well as household travel expenditures. Comparing the country-specific results, we find country-specific differences in the impact of RC on household categories, as well as similarities. The differences that we find indicate the importance of particular parameters for the evaluation of infrastructure pricing policy reforms. We can relate differences to prevalent country-specific differences in sociodemographic characteristics, land use structure, territorial population distribution, as well as macroeconomic indicators. To add substance to the two-country impact assessment, a sensitivity analysis is carried out, introducing different RC revenue use schemes. We find differences in distributional effects under equity concerns to be closely related to the revenue use pattern as well as to country- and household-specific travel demand profiles.Computable general equilibrium model, redistributive effects, road charging