Genetic draft, selective interference, and population genetics of rapid adaptation

To learn about the past from a sample of genomic sequences, one needs to understand how evolutionary processes shape genetic diversity. Most population genetic inference is based on frameworks assuming adaptive evolution is rare. But if positive selection operates on many loci simultaneously, as has recently been suggested for many species including animals such as flies, a different approach is necessary. In this review, I discuss recent progress in characterizing and understanding evolution in rapidly adapting populations where random associations of mutations with genetic backgrounds of different fitness, i.e., genetic draft, dominate over genetic drift. As a result, neutral genetic diversity depends weakly on population size, but strongly on the rate of adaptation or more generally the variance in fitness. Coalescent processes with multiple mergers, rather than Kingman's coalescent, are appropriate genealogical models for rapidly adapting populations with important implications for population genetic inference.Comment: supplementary illustrations and scripts are available at http://webdav.tuebingen.mpg.de/interference

Factors influencing the nematode community during composting and nematode-based criteria for compost maturity

Pilot studies indicate that shifts in the nematode species composition, life strategies and feeding behavior during composting appear to be fairly consistent and, therefore, promising as a potential tool to assess compost maturity. However, this has been only based on a limited number of, mainly, non-replicated observations. In this study, we tested whether the nematode community succession patterns are recurrent for parallel processes and assessed the relationship between the changes in the nematode community and potential important variables (i.e., temperature, duration of composting and the microbial community). The nematode and microbial community of three simultaneously running Controlled Farm Composting and a reference Green Waste composting process were analyzed through time. Bacterial-feeding enrichment opportunists were most numerous during and directly after the heat peaks. Subsequently, the bacterial-feeding/predator community dominated and the fungal-feeding nematodes became more dominant during maturation, confirming general community patterns from previous experiments. Nematode abundances significantly fluctuated with temperature and the relative abundance of fungal-feeding nematodes increased as the duration of the curing process increased. The amount of fungal-feeding nematodes was associated significantly with both duration of composting and temperature, and the F/(F + B) ratio was only significantly associated with duration of composting. Based on these results, and additional data from an industrial reference compost process and on available literature, a Nematode-based Index of Compost Maturity (NICM) is proposed, combining four nematode-based criteria (i.e., nematode abundance, F/(F + B) ratio, the presence of more than one fungal-feeding taxon and the presence of diplogasterids). Nevertheless, the NICM should be considered as work in progress which should be tested for a wider range of composts from diverse feedstock mixtures, locations (sites) and composting techniques, to validate the use of the index and allow more reliable interpretation of particular values of this index

A Barometer Element for Radio-Sondes

The barometer unit described herein has proven to be extremely reliable when used on balloon flights to high altitudes. It consists of an aneroid element which moves an arm, making a series of contacts with no mechanical amplification involved. Working on the digital principle it gives its information when certain definite pressures have been reached

Vibrating Vane, Absolute Gas Pressure Gauge

An oscillating rectangular vane suspended by a fine quartz fiber is used to determine the absolute pressure of the gas in which it is located. Aside from being an absolute instrument, the advantages of such a device are (1) simplicity, (2) the fact that it does not change the pressure when an observation is made as do many other types of gauges, and (3) the absence of a heated filament which may decompose the gas under study

Millikan-Teacher and Friend

As a result of support by Addison-Wesley Publishing Company, the American Association of Physics Teachers has established an annual lectureship, named in honor of Robert A. Millikan. It is anticipated that this will bring to each summer meeting of the Association a physicist who will speak on a topic of current interest and that the summer meeting will thus have a feature comparable with the Richtmyer Lecture at the annual meeting. The committee responsible for the first Millikan Lecture chose H. V. Neher, long time associate of Millikan. This highly suitable choice was as appropriate as was Neher's choice of a topic- Millikan himself. The editors of the American Journal of Physics are grateful for permission to publish this pleasantly informal biographical lecture, spiced as it is with personal reminiscences

Preferences for redistribution around the world

Gender, income, education and self-employment are robust predictors for individual support for redistribution in the OECD. In addition, considerations of social status, the fairness of the allocation mechanism, perceived moral worth of the poor and individual autonomy are important. The results for the OECD are compared to those for a large sample of non-OECD countries which also include less developed economies. Neither gender, nor self-employment, nor fairness considerations exhibit a robust association with preferences for redistribution. However, education, income, individual autonomy and moral worth of the poor remain important determinants. On average, preferences for redistribution indicate that within the OECD, there is no desire to change redistributive policies. In contrast, in the sample of non-OECD countries, on average there is a desire to redistribute less. --preferences for redistribution,social rivalry effect,social identity,survey data,World Values Survey

Universal central extensions of direct limits of Lie superalgebras

We show that the universal central extension of a direct limit of perfect Lie superalgebras L_i is (isomorphic to) the direct limit of the universal central extensions of L_i. As an application we describe the universal central extensions of some infinite rank Lie superalgebras

Income Inequality and Self-Reported Values

This paper offers a comprehensive econometric investigation of the impact of income inequality on the values endorsed by people. Using survey data from all thirty-four OECD countries over a period of almost thirty years, the following dimensions of value systems are investigated: work ethic, civism, obedience, honesty, altruism, and tolerance. In most cases, no robust effects from inequality on values are detected. However, there is evidence that a more unequal income distribution strengthens the work ethic of the population. Thus, income inequality seems to generate work incentives not only via the pecuniary reward of work but also through the symbolic reward it receives