[1] Nitrogen fixation supports new production in the oligotrophic oceans and removes dinitrogen and carbon dioxide from mixed layer waters. N-fixation rates have been estimated in various ways but measurements are still too rare and factors limiting N-fixation are not yet fully understood. Here we present data from a transect along 10 N through the tropical Atlantic on the Meteor Cruise 55 wher...

N limitation to primary production and other ecosystem processes is widespread. To understand the causes and distribution of N limitation, we must understand the controls of biological N fixation. The physiology of this process is reasonably well characterized, but our understanding of ecological controls is sparse, except in a few cultivated ecosystems. We review information on the ecological ...

BACKGROUND Tibial eminence fractures occur most commonly in skeletally immature children. Several techniques using physeal-sparing fracture fixation have been described, but their structural properties have not been evaluated. PURPOSE To determine the strength and resistance to displacement of physeal-sparing techniques used to fix tibial eminence fractures. STUDY DESIGN Controlled laborato...

In a series of experiments, the currently fixated word (word n) and/or the word to the right of fixation (word n+1) either disappeared or was masked during readers' eye fixations. Consistent with prior research, when only word n disappeared or was masked, there was little disruption to reading. However, when word n+1 either disappeared or was masked (either at the onset of fixation on word n or...

Global com parisons suggest that rates o f N fixation in tropical rain forests m ay be am ong the highest on earth. However, data supporting this contention are rare, and the factors th a t regulate N hxation w ithin the biom e rem ain largely unknow n. W e conducted a full-factorial (N X P) fertilization experim ent in two lowland tropical rain forests in C osta Rica to explore the effects o f...

Background: Respiratory problems are common after long bone fractures. The objective of the present investigation is to evaluate the effect of early fixation of femoral shaft fracture on the incidence of respiratory problems. Methods: The results of early and late stabilization of femoral shaft fractures were studied in 150 patients. The patients were divided into two groups according to the st...

The recent detection of heterotrophic nitrogen (N(2)) fixation in deep waters of the southern Californian and Peruvian OMZ questions our current understanding of marine N(2) fixation as a process confined to oligotrophic surface waters of the oceans. In experiments with Crocosphaera watsonii WH8501, a marine unicellular diazotrophic (N(2) fixing) cyanobacterium, we demonstrated that the presenc...