The distribution of many woodland herbs extends 1000–2000 km in a north– south direction, yet the majority of these species grow clonally, have little recruitment by seed, and possess no obvious mechanism for long-distance seed dispersal. Although aware that woodland herbs disperse poorly, ecologists have tacitly assumed that, given long periods of time, even small dispersal distances would all...

BACKGROUND Serial Analysis of Gene Expression (SAGE) is a DNA sequencing-based method for large-scale gene expression profiling that provides an alternative to microarray analysis. Most analyses of SAGE data aimed at identifying co-expressed genes have been accomplished using various versions of clustering approaches that often result in a number of false positives. PRINCIPAL FINDINGS Here we...

SAGE is an open source computer algebra system implemented using an object-oriented categorical framework, with methods for objects, methods for their elements, and methods for their morphisms. Currently, SAGE has the ability to deal with abelian groups, permutation groups, and matrix groups over a finite field. This paper will present an overview of the implementations of the group-theoretical...

Greater sage-grouse Centrocercus urophasianus (Bonaparte) currently occupy approximately half of their historical distribution across western North America. Sage-grouse are a candidate for endangered species listing due to habitat and population fragmentation coupled with inadequate regulation to control development in critical areas. Conservation planning would benefit from accurate maps delin...

The time series of differences in coincident measurements of ozone by Stratospheric Aerosol and Gas Experiment (SAGE) and by Solar Backscattered Ultraviolet (SBUV), SBUV/2, Umkehr and Microwave Limb Sounder (MLS) are analyzed, and the slopes in the differences are calculated. SAGE ozone measurements are also compared against those by HALOE. The purpose of these comparisons is to look for statis...

Land use is an indicator of the interaction between human and the environment on the earth surface. Recently, an increasing attention has been paid to the issue of impact of land use and land cover change on environment and water quality. In this paper, we analyzed the land use and land cover change by using RS and GIS, and simulated its implications in runoff from 1991 to 2000 using SCS model ...

Discount rates were estimated for Limited Resource Woodland Owners (LRWOs) in North Carolina and Virginia, using a survey that asked landowners to choose between two harvesting scenarios with different payment amounts and rotation lengths. Our innovative sampling frame resulted in a more diverse set of respondents, with high proportions of minority and small woodland owners. The estimated annua...

GENETICS, SOCIAL SCIENCES Retraction for ‘‘PKNOX2 gene is significantly associated with substance dependence in European-origin women,’’ by Xiang Chen, Kelly Cho, Burton H. Singer, and Heping Zhang, which published online August 31, 2009, in Proc Natl Acad Sci USA (10.1073/pnas.0908521106). The authors wish to retract this paper because its publication violates the Gene Environment Association ...