Late Quaternary arthropods from the Colorado Plateau, Arizona and Utah

Late Quaternary-age arthropods were recovered from dry cave deposits and packrat middens located in the Grand Canyon, Canyonlands, and Glen Canyon region of the Colorado Plateau. This Quaternary data resource has not been analyzed before from the Colorado Plateau national parks. Radiocarbon dates on the various deposits containing arthropods range from 1510 to 30,660 yr B.P. The fossil assemblages yielded 57 identified taxa of insects, arachnids, and millipedes, including 15 taxa taken to the species level. The information from the fossil insect record of the Colorado Plateau is not yet sufficiently detailed to permit precise paleoenvironmental reconstructions. However, preliminary conclusions suggest a cooler, moister climatic regime during the late Wisconsin glacial and a mosaic of vegetation types, such as grassland and shrubby communities, unlike the present vegetation at the localities.     

Holocene bison from Arches National Park, southeastern Utah

An artifact constructed from a bison ( Bison bison ) hornsheath was recovered from the surface of a sandstone shelter also containing skeletal remains of bison and bighorn ( Ovis Canadensis ). Radiocarbon dating of bison, bighorn, and the artifact indicate that all co-occurred on the central Colorado Plateau, southeastern Utah, either between A. D. 1405 and A. D. 1420, or between A. D. 1535 and A. D. 1605. Skeletal remains of the bison imply that the animal was of the local faunal community during the transition between Protohistoric and Historic time.     

A physical map of the mouse genome

A physical map of a genome is an essential guide for navigation, allowing the location of any gene or other landmark in the chromosomal DNA. We have constructed a physical map of the mouse genome that contains 296 contigs of overlapping bacterial clones and 16,992 unique markers. The mouse contigs were aligned to the human genome sequence on the basis of 51,486 homology matches, thus enabling use of the conserved synteny (correspondence between chromosome blocks) of the two genomes to accelerate construction of the mouse map. The map provides a framework for assembly of whole-genome shotgun sequence data, and a tile path of clones for generation of the reference sequence. Definition of the human-mouse alignment at this level of resolution enables identification of a mouse clone that corresponds to almost any position in the human genome. The human sequence may be used to facilitate construction of other mammalian genome maps using the same strategy.     

Late Quaternary vegetation and climate in the Escalante River Basin on the central Colorado Plateau

Five alcoves (rock shelters) in the Forty-Mile Canyon—Willow Gulch area of the Escalante River Basin in southeastern Utah yielded rich deposits of late Quaternary macrobotanical remains. The deposits were sampled and the contents identified in order to construct a chronology of vegetational change. Fourteen radiocarbon dates indicate that the fossils were deposited between 12,690 and 7510 yr B.P. (years before present). Ninety-one plant taxa were identified, 62 to species. Six species were common to all alcoves: Gambel oak ( Quercus gambelii ), box-elder ( Acer negundo ), prickly pear ( Opuntia subgenus Platyopuntia), skunkbush ( Rhus aromatica var. trilobata ), serviceberry ( Amelanchier utahensis ), and Indian ricegrass ( Oryzopsis hymenoides ). Late Pleistocene samples (>11,000 yr B.P.) contain extralocal, elevationally depressed species such as Douglas fir ( Pseudotsuga menziesii ), spruce ( Picea sp.), and mountain mahogany ( Cercocarpus ledifolius ), and mesophytic species such as rose ( Rosa woodsii ) and water birch ( Betula occidentalis ). Early Holocene samples (11,000-8000 yr B.P.) contain no elevationally depressed conifers, and the remaining mesophytic species decrease in relative abundance. Reticulated hackberry ( Celtis reticulata ) becomes common. The terminal Early Holocene sample (8000-7000 yr B.P.) contains abundant Gambel oak and prickly pear, but little else. Paleoclimatic interpretations for the Late Pleistocene correspond well to those of most other workers on the Colorado Plateau. Climates that were wetter and at least seasonally cooler than they are today are inferred from the macrobotanical assemblage. However, the increased moisture is attributed to higher stream base levels and increased groundwater rather than directly to increased precipitation. Early Holocene climates are interpreted as warmer and drier than those of the Late Pleistocene but still wetter than the present climate. Groundwater levels appear to be decreasing due to stream entrenchment. Terminal Early Holocene climates were much warmer and at least seasonally drier. By the end of the period, groundwater levels had decreased so much that the alcoves were unable to sustain plant communities; stream base level was probably near the present level.     

Developing Ourselves as Police Leaders: How Can We Inquire Collaboratively in a Hierarchical Organization?

This paper gives a practical account of a recent 18-month long action inquiry project, in which the author facilitated (and co-inquired with) a mixed group of police managers with the intention of improving our own leadership practices. Six phases of the inquiry are identified—doing the groundwork, getting the group together, creating a safe environment, sustaining the inquiry, accounting for the learning, and bridging the gaps. It is argued that such forms of collaborative inquiry are particularly well suited to addressing the uniquely complex phenomenon of leadership, and some tangible benefits for members of the project and for the organization as a whole are identified. Particular attention is paid to the politics and practicalities of doing collaborative inquiry in an overtly hierarchical organization, concluding that action inquiry must be crafted to its particular circumstances and context to realize its considerable potential to help us improve both individual practice and organizational performance.     

Snake Creek Burial Cave and a review of the Quaternary mustelids of the Great Basin

Snake Creek Burial Cave (SCBC), east central Nevada, is a unique paleontological deposit. The cave is the first natural trap excavated in the Great Basin and one of the few localities describing a valley-bottom community. The recovery of extinct Camelops sp. (camel) and Equus spp. (horse), in addition to radiometric dates, indicates at least some of the deposits to be of late Pleistocene age. Eight mustelid species have been identified from SCBC, including three species not previously reported from the late Rancholabrean of the Great Basin: Mustela nigripes (black-footed ferret), M. nivalis (least weasel), and Gulo gulo (wolverine). A review of late Pleistocene deposits indicates that there are more species of mustelids recovered from Snake Creek Burial Cave than from any other locality in the Great Basin.     

Late Pleistocene microtine rodents from Snake Creek Burial Cave, White Pine County, Nevada

A total of 395 microtine rodent specimens recovered from Snake Creek Burial Cave (SCBC) are referred to Microtus sp. and Lemmiscus curtatus . Radiocarbon and Uranium series dates indicated an age for these fossils of between 9460 ± 160 yr. B.P. and 15,100 ± 700 yr. B.P. The sample of lower first molars of Lemmiscus includes 4-, 5-, and 6-closed triangle morphotypes. Earlier reports of the 4-closed triangle morphotype are from Irvingtonian deposits in Colorado, Nevada, and New Mexico and from early Rancholabrean deposits in Washington. The morphotype is not known in living populations of Lemmiscus . SCBC specimens constitute the youngest record of the 4-closed triangle morphotype and are the only specimens reported from the late Rancholabrean. The time of disappearance of Lemmiscus with this molar morphology is unknown, but populations with this morphotype possibly became extinct at or near the end of the Pleistocene.     

A stop-codon mutation in the BRI gene associated with familial British dementia

Familial British dementia (FBD), previously designated familial cerebral amyloid angiopathy-British type, is an autosomal dominant disorder of undetermined origin characterized by progressive dementia, spasticity, and cerebellar ataxia, with onset at around the fifth decade of life. Cerebral amyloid angiopathy, non-neuritic and perivascular plaques and neurofibrillary tangles are the predominant pathological lesions. Here we report the identification of a unique 4K protein subunit named ABri from isolated amyloid fibrils. This highly insoluble peptide is a fragment of a putative type-II single-spanning transmembrane precursor that is encoded by a novel gene, BRI, located on chromosome 13. A single base substitution at the stop codon of this gene generates a longer open reading frame, resulting in a larger, 277-residue precursor. Release of the 34 carboxy-terminal amino acids from the mutated precursor generates the ABri amyloid subunit. The mutation creates a cutting site for the restriction enzyme XbaI, which is useful for detecting asymptomatic carriers. Antibodies against the amyloid or homologous synthetic peptides recognize both parenchymal and vascular lesions in FBD patients. A point mutation at the stop codon of BRI therefore results in the generation of the ABri peptide, which is deposited as amyloid fibrils causing neuronal disfunction and dementia.     

Stem growth and longevity dynamics for Salix arizonica dorn

Diameter-age relationships of Salix arizonica (Arizona willow) stems were investigated for 5 populations on the Markagunt, Paunsaugunt, and Sevier plateaus in southern and central Utah. Of the 430 stems studied, none exceeded 26 mm in diameter at ground level (estimated age of 19 yr). Equations developed for predicting age from stem diameters consistently accounted for over 90% of the observed variation. Slopes of predictive equations were homogenous across the 3 sites considered in detail. At 2 sties 46% and 38% of the stems exceed 10 mm (～ 7 yr old) diameter at ground level. At a 3rd site, no stems survived to exceed that size. Stem-age profiles at specific sites may thus be useful for assessing the relative favorability of local environments for the species.