|
|
|
|
|
| Hosmer, David W.; Royston, Patrick. |
| In this paper, we describe a new Stata command, stlh, which estimates and tests for the significance of the time-varying regression coefficients in Aalen’s linear hazards model; see Aalen (1989). We see two potential uses for this command. One may use it as an alternative to a proportional hazards or other nonlinear hazards regression model analysis to describe the effects of covariates on survival time. A second application is to use the command to supplement a proportional hazards regression model analysis to assist in detecting and then describing the nature of time-varying effects of covariates through plots of the estimated cumulative regression coefficients, with confidence bands, from Aalen’s model. We illustrate the use of the command to perform... |
| Tipo: Journal Article |
Palavras-chave: Survival analysis; Survival-time regression models; Time-to-event analysis; Research Methods/ Statistical Methods. |
| Ano: 2002 |
URL: http://purl.umn.edu/116019 |
| |
|
|
| Martins,Alexandre Cristante; Marchioretto,Rafaella Migliavacca; Vieira,Ariane Tonetto; Stiehl-Alves,Eudes Maria; Santos,Eliane Kaltchuk dos; Souza-Chies,Tatiana Teixeira de. |
| ABSTRACT South Brazilian grasslands are among the most species-rich grasslands worldwide yet they have been suffering ongoing degradation due to land-use. Little is known about the reproductive ecology of the native species of these grasslands. Thus, our goal was to characterize seed traits and germination requirements of three native species of the tribe Tigridieae (Iridaceae, Iridoideae) due to its richness in the Pampa biome and the contrasting morphology, cytogenetics, and geographic distributions of its representatives. We tested if closely related species possess similar seed traits and whether species with wider distributions have broader germination requirements. Seed production and mass were estimated, and morphological analyses, germination... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dormancy; Functional traits; Germination; Grasslands; Iridaceae; Photoinhibition; Regeneration niche; Reproductive ecology; Seed morphology; Time-to-event analysis. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062020000400730 |
| |
|
|
|
