Geological Survey of Victoria: Southeast Lachlan Crustal Transect

United States Geological Survey

Zigzag Survey Designs in Line Transect Sampling

Zigzag survey lines are frequently used in shipboard and aerial line transect surveys of animal populations. Analysis proceeds assuming that coverage probability through the survey region is uniform. We show that the two types of zigzag design that are in wide use do not generally have this property, and explore the degree of bias in abundance estimates that can be anticipated. We construct a z...

An Extended Lachlan Splitting Theorem

We show that the top of any diamond with bottom 0 in the r.e. degrees is also the top of a stack of n diamonds with bottom 0. Let R be the upper semilattice of the recursively enumerable degrees. A minimal pair consists of two incomparable r.e. degrees with innmum equal to the recursive degree 0. An r.e. degree is cappable if it is one half of a minimal pair. An r.e. degree a is the top of a di...

On a Theorem of Lachlan and Martin

In [3] we raised the following question: does there exist a recursively enumerable degree d such that 0(n)<d(n)<0(n+1) for all wjSO? This question was answered affirmatively by Lachlan [l] and by Martin [2]. Lachlan's proof combines a familiar priority argument with the fixed point theorem of Kleene. Martin's proof is a new form of priority argument based on Theorem 3 of section 6 of [3]. In th...

U . S . Geological Survey Karst Interest Group

Congress mandated the establishment of the National Cave and Karst Research Institute in October 1998 to further the science of speleology by facilitating research, to enhance public education, and to promote environmentally sound cave and karst management. Considerable progress has been made during the tenure of the Interim Director (2000-2002) toward making the Institute operational. The scop...