We evaluated three possible functions of clonal growth related to genet persistence in the root-suckering understory tree pawpaw, Asimina triloba (L.) Dunal: (1) risk spreading through multiplication of stems, (2) enhanced establishment and survival of new stems, and (3) horizontal expansion growth of patches. The number, diameter growth, and spatial distribution of annual stem recruits were ex...

Hurricane winds can have large impacts on forest structure and dynamics. To date, most evaluations of hurricane impacts have focused on short-term responses after a hurricane, often lacked pre-hurricane measurements, and missed responses occurring over longer time scales. Here, we use a long-term data set (1974–2009, 35 years) of tree stems (.3 cm in diameter at 1.3 m aboveground) in four sites...

After total hip replacement, some cemented titanium stems show above-average early loosening rates. Increased release of wear particles and resulting reaction of the peri-prosthetic tissue were considered responsible. The objective was to develop a test method for analysing the abrasive wear behaviour of cemented stems and for generating wear particles at the interface with the bone cement. By ...

BACKGROUND AND PURPOSE Under physiological loads, debonded cemented femoral stems have been shown to move within their cement mantle and generate a fluid pump that may facilitate peri-prosthetic osteolysis by pressurizing fluid and circulating wear debris. The long-term physiological loading of rough and polished tapered stems in vitro has shown differences in performance, with greater interfac...

BACKGROUND AND PURPOSE High pressures around implants can cause bone lysis and loosening. We investigated how pressures are generated around cemented femoral stems. METHOD We compared the pressures generated by rough and polished tapered stems at their cement interfaces, in an in vitro model, before and after 1 million load cycles. RESULTS At the start of the study, the loading of both poli...

The roots of the understorey shrub Carapichea ipecacuanha (ipecac) have medicinal properties, and the uprooting of wild plants has supplied most of the world demand for this species. Although under severe population decline, C. ipecacuanha lacks legal protection. In the wild, the aerial stems of ipecac clump together to form clusters with well-defined borders. Cluster size may range from severa...

this paper provides an analysis of persian verbs within the framework of optimality theory. to be more specific, it mainly cocentrates on past and present stems of persian verbs. since analyzing this subject within the derivational framework would result phonological rules which are not natural, it is analysed by optimality theory which is one of the constraint-based approach. based on this, we...