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This study compared Web-based assessment techniques with traditional paper-based methods of commonly used measures of alcohol use. Test-retest reliabilities were obtained, and tests of validity were conducted. A total of 255 participants were randomly assigned to 1 of 3 conditions: paper-based (P&P), Web-based (Web), or Web-based with interruption (Web-I). Follow-up assessments 1 week later indicated reliabilities ranging from .59 to .93 within all measures and across all assessment methods. Significantly high test-retest reliability coefficients support the use of these measures for research and clinical applications. Furthermore, no significant differences were found between assessment techniques, suggesting that Web-based methods are a suitable alternative to more traditional methods. This cost-efficient alternative has the advantage of minimizing data collection and entry errors while increasing survey accessibility.

The diverse collections of microorganisms associated with humans and other animals, collectively referred to as their "microbiome," are critical for host health, but the mechanisms that govern their assembly are poorly understood. This has made it difficult to identify consistent host factors that explain variation in microbiomes across hosts, despite large-scale sampling efforts. While ecological theory predicts that the movement, or dispersal, of individuals can have profound and predictable consequences on community assembly, its role in the assembly of animal-associated microbiomes remains underexplored. Here, we show that dispersal of microorganisms among hosts can contribute substantially to microbiome variation, and is able to overwhelm the effects of individual host factors, in an experimental test of ecological theory. We manipulated dispersal among wild-type and immune-deficient knockout zebrafish and observed that interhost dispersal had a large effect on the diversity and composition of intestinal microbiomes. Interhost dispersal was strong enough to overwhelm the effects of host factors, largely eliminating differences between wild-type and immune-deficient hosts, regardless of whether dispersal occurred within or between genotypes, suggesting dispersal can independently alter the ecology of microbiomes. Our observations are consistent with a predictive model that assumes metacommunity dynamics and are likely mediated by dispersal-related microbial traits. These results illustrate the importance of microbial dispersal to animal microbiomes and motivate its integration into the study of host-microbe systems.

Biological diversity depends on the interplay between evolutionary diversification and ecological mechanisms allowing species to coexist. Current research increasingly integrates ecology and evolution over a range of timescales, but our common conceptual framework for understanding species coexistence requires better incorporation of evolutionary processes. Here, we focus on the idea of evolutionarily stable communities (ESCs), which are theoretical endpoints of evolution in a community context. We use ESCs as a unifying framework to highlight some important but under‐appreciated theoretical results, and we review empirical research relevant to these theoretical predictions. We explain how, in addition to generating diversity, evolution can also limit diversity by reducing the effectiveness of coexistence mechanisms. The coevolving traits of competing species may either diverge or converge, depending on whether the number of species in the community is low (undersaturated) or high (oversaturated) relative to the ESC. Competition in oversaturated communities can lead to extinction or neutrally coexisting, ecologically equivalent species. It is critical to consider trait evolution when investigating fundamental ecological questions like the strength of different coexistence mechanisms, the feasibility of ecologically equivalent species, and the interpretation of different patterns of trait dispersion.

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L-929 cells were killed when approximately 50 viable Rickettsia prowazekii organisms per L-cell were centrifuged onto a monolayer. The glycerophospholipids of the L-cell were hydrolyzed to lysophosphatides and free fatty acids. Concomitantly, there was a loss of membrane integrity as shown by release of lactate dehydrogenase and 86Rb and permeability to trypan blue dye. No glycerophospholipid hydrolysis or cytotoxicity occurred when the rickettsiae were inactivated by heat, UV irradiation, N-ethylmaleimide, or metabolic inhibitors before their addition to the L-929 cells. On the other hand, treatment of the L-929 cells with the cytoskeleton agents colchicine or cytochalasin B or with Nethylmaleimide inhibited neither the phospholipase A activity nor the loss of membrane integrity. Cytochalasin B-treated cells could be damaged by even small numbers of rickettsiae. We suggest that this phospholipase A activity is used by the rickettsiae to escape from the phagosomes into the cytoplasm of host cells.

Longitudinal data from 81 undergraduates (47 women and 34 men) were used for concurrent and predictive validation of binge drinking measures. Results suggest relative strengths and weaknesses of different binge definitions. The conventional binge measure of ^5 drinks in a row (24 drinks in a row for women) yielded higher prevalence estimates and higher sensitivity but less specificity than other quantityfrequency measures using alcohol-related problems as the criterion. Alternative binge measures resulted in lower prevalence rates and sensitivity but higher specificity for alcohol-related problems. Only a subset of students exhibited heavy drinking patterns consistently over time. Such consistent heavy drinking was significantly more strongly associated with increased risk of adverse alcohol-related consequences.

The use of emergent Web-based computer technology offers an unprecedented opportunity to conduct cross-sectional and longitudinal research studies in a cost-efficient manner while increasing survey accessibility to study participants and providing a more accurate data collection alternative to researchers (Miller, 1997). Costs associated with traditional assessment methods, such as publishing and distributing paper surveys, mailing materials to and telephoning study participant reminders, and data collection and entry are eliminated. The estimated costs to develop, publish, and maintain Web-based surveys are significantly lower (Schmidt, 1997). In addition, the data retrieved from Web-based surveys are potentially more accurate and more complete, and they provide essentially clean data moments after the survey is completed. The Web may prove superior to paper because it potentially provides increased accessibility; capability for dynamic and interactive forms, which eliminate the