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In a replicated field experiment we studied the effects of natural densities of two exotic consumers, the predatory and herbivorous signal crayfish (Pacifastacus leniusculus) and the predatory rainbow trout (Oncorhynchus mykiss), on multiple trophic levels of a pond community. The goals were to: (1) determine the individual and combined effects of predators on macroinvertebrates, macrophytes, and periphytic algae; (2) evaluate the strength of direct and indirect interactions in a food web influenced by omnivores; and (3) evaluate the relative importance of direct and indirect predator effects on mortality and growth of a native frog species, Rana temporaria. The experiment showed that both signal crayfish and rainbow trout had strong effects on multitrophic levels of a littoral pond community, through direct consumption and indirect effects on lower trophic levels. Crayfish had weak but significant negative effects on the biomass of predatory invertebrates and greatly reduced the biomass of snails, the most abundant invertebrate grazers. Although the number of active herbivorous tadpoles tended to be higher in crayfish cages relative to control cages, the proportion of surviving froglets was lower in crayfish cages than in control cages, possibly due to crayfish predation on injured tadpoles. The size of surviving froglets did not differ from controls, but tadpoles in crayfish cages often suffered tail injuries. Macrophyte coverage decreased as a result of crayfish consumption and nonconsumptive fragmentation. However, the biomass of periphyton increased in crayfish cages relative to controls, probably due to reduced grazing from snails. In contrast, trout had strong negative effects on the biomass of both predatory invertebrates and insect grazers, whereas trout had less effect on snail biomass than did crayfish. Also, in contrast to crayfish cages, the number of active tadpoles in trout cages was lower than in controls, probably due to a combination of trout predation and trout‐induced reduced tadpole activity. Trout had a strong negative impact on froglet survival, and froglets in trout cages metamorphosed at a smaller size and had reduced growth rates compared to froglets in crayfish and control cages. As with crayfish, the biomass of periphyton increased in trout cages relative to controls, which may be due to a combination of both density and trait‐mediated trout effects on tadpole grazing. In treatments with multiple predators the effects of crayfish and trout on caged communities were independent, and there were few interactions. Mostly effects of combined predators reflected those in single predator cages. Our results demonstrate that noninteracting, introduced multiple predators can have strong direct and indirect effects on multiple trophic levels in pond communities. Trophic cascades may develop in aquatic food webs even with omnivores such as crayfish, and in complex habitats with trout. These strong indirect effects are mediated through both predation on important grazers (i.e., the crayfish–snail–pe...

The increasing complexity of randomized clinical trials and the practice of obtaining a wide variety of measurements from study participants have made the consideration of multiple endpoints a critically important issue in the design, analysis, and interpretation of clinical trials. Failure to consider important outcomes can limit the validity and utility of clinical trials; specifying multiple endpoints for the evaluation of treatment efficacy, however, can increase the rate of false positive conclusions about the efficacy of a treatment. We describe the use of multiple endpoints in the design, analysis, and interpretation of pain clinical trials, and review available strategies and methods for addressing multiplicity. To decrease the probability of a Type I error (i.e., the likelihood of obtaining statistically significant results by chance) in pain clinical trials, the use of gatekeeping procedures and other methods that correct for multiple analyses is recommended when a single primary endpoint does not adequately reflect the overall benefits of treatment. We emphasize the importance of specifying in advance the outcomes and clinical decision rule that will serve as the basis for determining that a treatment is efficacious and the methods that will be used to control the overall Type I error rate.

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The influence of pronation and supination of the foot on the joints of the ankle/foot complex was analyzed three dimensionally by roetgen stereophotogrammetry in eight healthy volunteers. Radiopaque markers were introduced into the tibia, talus, calcaneus, navicular, medial cuneiform, and first metatarsal bones. The subjects stood on a platform that was tilted in 10 degree-steps from 20 degrees of pronation to 20 degrees of supination. Pairs of x-ray exposure were made in each position. Calculation of resulting joint deviations from the neutral position showed that the largest amounts of motion occurred in the talonavicular joint followed by the talocalcaneal joint, in the latter case mainly in supination. The joints proximal and distal to the medial cunriform also participated substantially in the total motion registered. The tibia showed an average of 0.2 degrees of external rotation for each degree of supination of the foot.

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Pomatoschistus minutus show paternal care in a resource defence mating system. We investigated the effect of nest‐site availability on parasitic spawning. Each experimental pool contained four potentially nest‐building males, four females and nests‐sites in shortage (2) or excess (6). Both treatments were conducted in two populations; one with natural nest‐sites in excess, one with a nest‐site shortage. Microsatellite‐DNA revealed that all nest‐holders had fertilized most of the eggs they tended. Yet, 35% of the nests contained eggs fertilized by another male and 14.4% of the males had performed parasitic spawning. There was no site or treatment effect. Several females spawned in two nests, which coincided with parasitic spawnings, suggesting a cost to the nest‐holder in terms of lost mating success. Nest‐holders with and without eggs and non‐nesting males all spawned parasitically, generating a significantly lower opportunity for sexual selection compared to if there had been no parasitic spawning.

In an in vivo kinematical investigation, the movements of the ankle/food complex induced by external rotation of the leg from an internally rotated position were analyzed by roentgen stereophotogrammetry. Radiopaque markers were introduced into the tibia, talus, calcaneus, navicular, medial cuneiform, and first metatarsal bones of eight healthy volunteers. Rotations occurring between these bones after 10 degrees increments of leg rotation were calculated in three dimensions. Movement of the leg from an internally rotated position to the neutral was found to induce motion mainly as internal rotation of the talus in relation to the tibia. Further external rotation induced motion mainly in the talonavicular and talocalcaneal joints, whereas a smaller amount of motion was seen in the joint between the navicular and the medial cuneiform.