Bayesian clustering algorithms ascertaining spatial population structure: a new computer program and a comparison study

On the basis of simulated data, this study compares the relative performances of the Bayesian clustering computer programs structure , geneland , geneclust and a new program named tess . While these four programs can detect population genetic structure from multilocus genotypes, only the last three ones include simultaneous analysis from geographical data. The programs are compared with respect to their abilities to infer the number of populations, to estimate membership probabilities, and to detect genetic discontinuities and clinal variation. The results suggest that combining analyses using tess and structure offers a convenient way to address inference of spatial population structure.     

Survival and recovery of perennial forage grasses under prolonged Mediterranean drought: I. Growth, death, water relations and solute content in herbage and stubble

Swards of Dactylis glomerata cultivars (cvs) KM2 and Lutetia and of Lolium perenne cvs Aurora and Vigor were grown under full irrigation or prolonged summer drought (80 d) in a field experiment in the South of France.
After irrigation was withheld, leaf extension rates of all cvs fell by 90% within 9–12 d, and rapid scorching of laminae followed. Tiller mortality at the end of the drought was very different in the cocksfoot cvs (4% for KM2 and 76% for Lutetia) and intermediate (41%) for both ryegrass cvs. Following re-watering, rates of herbage regrowth were closely correlated with tiller survival. Measured minerals contributed c . 0·52 MPa to osmotic potential in all treatments, whereas water-soluble carbohydrates (WSC) contributed 0·25 MPa under irrigation and 0·46 MPa during drought.
There was no systematic difference between the two species for summer survival under severe drought, but large differences between the cocksfoot cvs. The traits most strongly associated with superior survival were: (a) a deep root system and greater water uptake at depth; (b) low water and osmotic potentials in surviving laminae, i.e. better tolerance to dehydration; (c) large pool-size of WSC reserves (fructans having degree of polymerization >4) in entire tiller bases (stubble); (d) low accumulation of proline in stubble; (e) rapid nitrogen uptake after rewatering.     

Recycled Sandalistas: From Revolution to Resorts in the New Nicaragua

In the post-Sandinista period, Nicaragua has adjusted to the new terms of a neoliberal economy by turning to tourism development as a leading industry. As the nation is refashioned as a safe and desirable tourist destination, efforts have been made to conceal evidence of the recent revolutionary past that might discourage visitors from traveling to the country. Nevertheless, there are indications that selected images and memories of revolution are making a reappearance and may prove marketable for tourism. This article argues that the twin projects of neoliberalism and nationalism may be served by this seemingly contradictory process. The Nicaraguan case offers an example of how the past figures in the remaking of postrevolutionary nations for tourism in the era of globalization.     

Novel chloroplasts and unusual cellular ultrastructure in the "resurrection" plant Myrothamnus flabellifolia Welw. (Myrothamnaceae)

The vacuoles of three "resurrection" plants, Myrothamnus flabellifolia, Anastatica hierochuntica and Selaginella dregei were found to contain large quantities of osmiophilic material which may be part of the "resurrection" mechanism. Myrothamnus differed from the others by having mitochondria, and possibly plastids, which are separated from the remainder of the cytoplasm by sheaths or membranes during desiccation. Upon "resurrection" these barriers appear to be perforated and explain in part the faster rate of "resurrection" in Myrothamnus than in other "resurrection" plants. The chloroplasts of Myrothamnus are remarkable in that they possess "staircase" granum stacks of a type not previously described in any other plant tissue.     

Tangible evidence of historic Australian indigenous savanna management

Knowledge of historic indigenous management practices in north Australian tropical savannas can benefit contemporary management by providing a long‐term ecological context. This study provides understanding of how indigenous peoples managed their resources during the period of colonization by Europeans. Traditional management practices and resource use were observed by the European explorers and missionaries, anthropologists and ethnographers who followed. The historic record shows that the savannas were managed intensively by indigenous peoples, even during the colonization era. Across the region they used fire throughout the dry seasons, which is recognized by ecologists today. Importantly, and not previously reported in the ecological literature, they constructed water wells that provided them with extended use of country into the dry seasons, built and managed fisheries to enhance and extend their food supplies, and created extensive walking paths. These findings are significant because previous ecological research has assumed implicitly that indigenous people in the region were dependent on natural waters and therefore subject to seasonal availability of water to enable them to penetrate and live in dry country, and has given scant acknowledgement of manipulation of resources. The anthropological studies were compromised by the devastating social disruptions caused by the colonizers (mostly cattle ranchers and miners) and subsequent missionaries and government administrators. Despite these disruptions, the evidence demonstrates continuity of knowledge and management practices in much of the region. This history provides contemporary ecologists and managers with evidence of consistent patterns of resource management from earlier times. The evidence also shows that indigenous people were less at the mercy of the environment than has been assumed previously. The combined evidence suggests that contemporary management should consider that traditional management practices over many thousands of years were active and ubiquitous, and continued into the present era and probably shaped the biota of the region.     

DETERMINATION OF SENSORY OIL-WATER PARTITION COEFFICIENTS OF SINGLE AROMA COMPOUNDS COMBINING PANELIST FREE INTENSITY RATING AND THEORETICAL MODELING OF ODOR INTENSITY

Using an intensity rating with no external calibration, experiments were designed to measure the sensory oil-water partition coefficients of four aroma molecules (benzaldehyde, ethyl butyrate, linalool and acetophenone) as the ratios of concentration producing stimuli of equivalent intensities. Flavored water and oil phases were successively assessed for odor intensity by 24 panelists who were given total freedom regarding scaling strategy. Each session combined five concentration levels of three out of the four studied aromas in a solvent (water or oil). A predominant concentration effect was found for each aroma in both solvents and concentration dependencies of perceived intensity above water and oil were similar. Experimental data were modeled with Fechner, Stevens and Hill equations. Combining results above water and oil solutions to feed a common model led to the evaluation of an overall sensory oil-water partition coefficient for each aroma compound. All three models produced similar partition coefficient values for each aroma that were lower than the related instrumental partition coefficients. Biases previously detected when external calibration had been used were reduced in a large proportion while suggested enhancement of odor intensity by water vapor could not be excluded.