A Messy, but Instructive, Case Study in Design of Experiments

A company manufacturing fans wished to conduct an experimental design to determine the best combination of three factors affecting the breaking torque of the fans. Analysis of the data ceased to be straightforward when the authors found that the data failed the test for homogeneity of variances. After unsuccessfully attempting to transform the data and thereby meet the assumptions necessary to carry on the analysis, the authors relied upon a graphical analysis and a careful study of the means for each design point. This paper describes a statistically sound but novel strategy used to complete the analysis

Biogeography of Arkansas Mammals with Notes on Species of Questionable Status

Seventy-one native or re-introduced species of mammals were analyzed with respect to their geographical distributions and relationships to the four broad physiographical regions of Arkansas. Mammalian diversity in the Ozark Mountains, Ouachita Mountains/ Arkansas River Valley, Gulf Coastal Plain, and Mississippi Alluvial Plain/Crowley\u27s Ridge was not area dependent. The majority of mammalian species (44) occurs statewide with the greatest diversity in the interior highland regions. The Ozark Mountains contain the most species endemic to an area. Thirteen species which are of questionable status in Arkansas are discussed. The presence of the plains pocket gopher (Geomys bursarius), a second species of pocket gopher in Arkansas, is noted. New distributional maps for the desert shrew (Notiosorex crawfordi) and small-footed bat (Myotisleibii)are presented

Distribution of Baird\u27s Pocket Gopher (Geomys breviceps) In Arkansas; with Additional County Records

Recently, a population of pocket gophers in the north-central portion of Arkansas was determined to be the plains pocket gopher (Geomys Imrsarius), rather than Baird\u27s pocket gopher (Geomys breviceps). This changed the known range of both species extensively. A detailed examination of the known range of Baird\u27s pocket gophers (G. breviceps) in Arkansas resulted in 12 new county records. Biogeographically, G. breviceps appears to be found in all physiographic regions within the state with the possible exception ofCrowley\u27s ridge. It is most common in the Gulf Coastal Plain and rarest in the Mississippi Alluvial Plain. The distribution ofG. breviceps is consistent with the hypothesis that glaciation events, together withnorthward invasions from Louisiana and eastern Texas and eastward invasions from Oklahoma (around the Ouachita Mountains) were major creational forces in the establishment of the present G. breviceps distribution in Arkansas

Inferring Market Structure from Customer Response to Competing and Complementary Products

We consider customer influences on market structure, arguing that market structure should explain the extent to which any given set of market offerings are substitutes or complements. We describe recent additions to the market structure analysis literature and identify promising directions for new research in market structure analysis. Impressive advances in data collection, statistical methodology and information technology provide unique opportunities for researchers to build market structure tools that can assist “real-time” marketing decision-making.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46981/1/11002_2004_Article_5088105.pd

An improved predictive recognition model for Cys2-His2 zinc finger proteins

Cys2-His2 zinc finger proteins (ZFPs) are the largest family of transcription factors in higher metazoans. They also represent the most diverse family with regards to the composition of their recognition sequences. Although there are a number of ZFPs with characterized DNA-binding preferences, the specificity of the vast majority of ZFPs is unknown and cannot be directly inferred by homology due to the diversity of recognition residues present within individual fingers. Given the large number of unique zinc fingers and assemblies present across eukaryotes, a comprehensive predictive recognition model that could accurately estimate the DNA-binding specificity of any ZFP based on its amino acid sequence would have great utility. Toward this goal, we have used the DNA-binding specificities of 678 two-finger modules from both natural and artificial sources to construct a random forest-based predictive model for ZFP recognition. We find that our recognition model outperforms previously described determinant-based recognition models for ZFPs, and can successfully estimate the specificity of naturally occurring ZFPs with previously defined specificities

Vocational Implications of Post-polio Syndrome

Of more than 1,000,000 survivors of poliomyelitis living in the United States, about 80% experience symptoms associated with post-polio syndrome (PPS). New weakness, fatigue, and pain are the most common symptoms that may appear years after acute polio. PPS is reported to be the most prevalent progressive neuromuscular disease in North America. The physical symptoms of PPS can be severe enough to decrease an individual’s quality of life, significantly alter work function, and impose lifestyle changes. The psychological implications of battling once again with a disease that had stabilized decades ago can be devastating. Rehabilitation physicians and counselors knowledgeable of post-polio syndrome and its possible impact on employment can have a positive influence on persons with PPS

Vocational Implications of Post-polio Syndrome

Of more than 1,000,000 survivors of poliomyelitis living in the United States, about 80% experience symptoms associated with post-polio syndrome (PPS). New weakness, fatigue, and pain are the most common symptoms that may appear years after acute polio. PPS is reported to be the most prevalent progressive neuromuscular disease in North America. The physical symptoms of PPS can be severe enough to decrease an individual’s quality of life, significantly alter work function, and impose lifestyle changes. The psychological implications of battling once again with a disease that had stabilized decades ago can be devastating. Rehabilitation physicians and counselors knowledgeable of post-polio syndrome and its possible impact on employment can have a positive influence on persons with PPS