Mixing of Xi_c and Xi_c' Baryons

The mixing angle between the Xi_c and Xi_c' baryons is shown to be small, with a negligible shift in the Xi_c masses.Comment: One missprint corrected. The numerator of Eq. (12) should read {2[(Sigma_c^{*++}-Sigma_c^{++})-(Xi_c^{*+}-Xi_c^{'+})]} The correct equation was used in the calculation so no other change is mad

A study of systems implementation languages for the POCCNET system

The results are presented of a study of systems implementation languages for the Payload Operations Control Center Network (POCCNET). Criteria are developed for evaluating the languages, and fifteen existing languages are evaluated on the basis of these criteria

A Spatially Explicit Census Reveals Population Structure and Recruitment Patterns for a Narrowly Endemic Pine, Pinus torreyana

We conducted a census of the rare pine, Pinus torreyana ssp.  torreyana, in order to determine: a) what is the population size and is it stable, growing or declining; b) what is the spatial variation in population structure; c) what is the spatial patterning of trees in different life stages; and, d) what environmental factors are related to seedling recruitment?  Trees were classified into four stages classes: adult (160 cm tall with cones); sub-adult (160 cm without cones); saplings (30-160 cm), and seedlings (30 cm).  Stem diameter was measured for adults and sub-adults, and height for saplings and seedlings.  Stands were defined by spatial clustering of the tree map.  Univariate and bivariate point pattern analyses were used to explore spatial patterns for adult and juvenile trees and identify potential stand development processes such as density dependence, dispersal limitations, and patchy recruitment.  Logistic regression was used to analyze seedling establishment and survival in relation to environmental variables derived from digital maps.  We expected to find little or no recruitment based on earlier studies.  Instead, 5422 trees were mapped and measured, and tree size had “reverse J-shaped†distribution suggestive of a recruiting population.  However, population structure was variable among stands.  The predominant spatial pattern detected for adult and juvenile trees was clustering at lag distances 10 m.  Bivariate pattern analysis did not suggest repulsion between adult and juvenile size classes.  Seedlings tended to be found close to adults and on certain soil types.  Taken together, this suggests that the clustered patterns resulting from patchy recruitment and survival of juveniles persist over time.