Search results for "3-YEAR"
showing 4 items of 4 documents
Evolutionary Hysteresis and Ratchets in the Evolution of Periodical Cicadas
2019
It has been previously hypothesized that the perfectly synchronized mass emergence of periodical cicadas (Magicicada spp.) evolved as a result of a switch from size-based to age-based emergence. In the former case, cicada nymphs emerge immediately (at the first opportunity) on reaching maturity, whereas in the latter case, nymphs wait in order to emerge at a specific age. Here we use an individual-based model to simulate the cicada life cycle and to study the evolution of periodicity. We find that if age-based emergence evolves in a constant abiotic environment, it typically results in a population that is protoperiodic, and synchronous emergence of the whole population is not achieved. How…
Hybridization selects for prime‐numbered life cycles in Magicicada: An individual‐based simulation model of a structured periodical cicada population
2020
Abstract We investigate competition between separate periodical cicada populations each possessing different life‐cycle lengths. We build an individual‐based model to simulate the cicada life cycle and allow random migrations to occur between patches inhabited by the different populations. We show that if hybridization between different cycle lengths produces offspring that have an intermediate life‐cycle length, then predation acts disproportionately to select against the hybrid offspring. This happens because they emerge in low densities without the safety‐in‐numbers provided by either parent population. Thus, prime‐numbered life cycles that can better avoid hybridization are favored. How…
OARSI/OMERACT Initiative to Define States of Severity and Indication for Joint Replacement in Hip and Knee Osteoarthritis. An OMERACT 10 Special Inte…
2011
Objective.To define pain and physical function cutpoints that would, coupled with structural severity, define a surrogate measure of “need for joint replacement surgery,” for use as an outcome measure for potential structure-modifying interventions for osteoarthritis (OA).Methods.New scores were developed for pain and physical function in knee and hip OA. A cross-sectional international study in 1909 patients was conducted to define data-driven cutpoints corresponding to the orthopedic surgeons’ indication for joint replacement. A post hoc analysis of 8 randomized clinical trials (1379 patients) evaluated the prevalence and validity of cutpoints, among patients with symptomatic hip/knee OA.…
Vārdu krājuma aktivizēšana 2 – 3 gadus veciem bērniem didaktiskajās rotaļās
2022
Kvalifikācijas darba tēma: “Vārdu krājuma aktivizēšana 2 – 3 gadus veciem bērniem didaktiskajās rotaļās”. Kvalifikācijas darba autore: Elīna Šustere. Kvalifikācijas darba mērķis: teorētiski izpētīt un praktiski pārbaudīt 2 – 3 gadus vecu bērnu vārdu krājuma aktivizēšanas iespējas didaktiskajās rotaļās. Pētījuma teorētiskajā daļā tika analizēta zinātniskā literatūra par bērnu runas un valodas attīstības likumsakarībām un vārda krājuma aktivizēšanas iespējām, izmantojot didaktiskās rotaļas. Pētījuma empīriskajā daļā ir atspoguļoti vecāku aptaujas rezultāti, kas parāda katra bērna aktīvā vārdu krājuma lielumu, kā arī katra bērna raksturojums. Tajā ir ietverta pētījumā iegūto datu analīze un pē…