A GIS model to predict the location of fossil packrat ( Neotoma ) middens in central Nevada

Fossil packrat ( Neotoma ) middens provide an important source of paleoecologic data in the arid West. This study describes and tests a predictive GIS model that uses the eights-of-evidence method for determining areas with a high probability of containing fossil middens in central Nevada. Model variables included geology, elevation, and aspect. Geology was found to be the most important variable tested. We produced a map of 4 probability classes validated by field-checking 21 randomly selected 1-km 2 sites throughout the study area. Our high-probability category reduced the search area to only 3.5% of the total study area. Fossil middens were found on 8 of 21 sites (38%). Geologic types that contained middens were granite, limestone, and volcanic tuff. A 2nd run of the model with the new midden localities added to the training set helped narrow the total search area even further. This analysis demonstrates that the weights-of-evidence method provides an effective tool both for guiding research design and for helping locate midden sites within specific localities. With only a limited training dataset and a simple set of mapped criteria, a model can be constructed that is both predictive and testable. We intend to continue development of the model to improve our ability to predict the location of Pleistocene-age middens and to locate middens on low-probability sites. This method, designed for mineral exploration, has wide potential application within the natural sciences.     

Genetic variation and population structure in the cliff chipmunk, Eutamias dorsalis , in the Great Basin of western Utah

Allelic variation at 21 of 39 electrophoretically resolved enzyme loci was used to examine patterns of geographic differentiation and population structure in six allopatric samples of Eutamias dorsalis . Coefficients of genetic similarity for paired combinations of E. dorsalis samples ranged from 0.955 to 0.975, except for one population that was 0.900. Conservative genic divergence among five populations is proposed to be the result of relatively recent isolation events. High positive F 18 values and chi– square analyses confirm a significant excess of homozygotes at several loci at the five localities for which sample sizes were statistically adequate. This may be partly attributable to inbreeding, a Wahlund effect, linkage disequilibrium, posttranslational modification, or some combination of these; but at present some of these alternatives cannot be excluded in favor of a single explanation. Some samples were collected across altitudinal gradients of over 800 m, suggesting that a Wahlund effect may be the most likely explanation for low levels of heterozygosity in these populations.     

Influence of black-tailed prairie dog towns ( Cynomys ludovicianus ) on carnivore distributions in the Oklahoma Pandhandle

Carnivores were recorded at prairie dog towns and non-prairie dog town paired sites in the Oklahoma Panhandle over 4 sampling sessions from October 1995 to February 1997. We established carnivore presence through the use of baited tracking plates dusted with chalk and matched with infrared-triggered cameras. Five carnivore species were recorded at both prairie dog towns and paired sites across the Oklahoma Panhandle. Of these, 4 were recorded with sufficient regularity to permit analyses. Carnivores were analyzed at prairie dog towns across the entire Panhandle and in the Panhandle's westernmost county (Cimarron County) only. Canids showed no significant preference for prairie dog towns or other areas. In the Oklahoma Panhandle and Cimarron County only, occurrence of swift fox ( Vulpes velox ) between prairie dog towns and control sites was insignificant. Badgers ( Taxidea taxus ) and spotted skunks ( Spilogale putorius ) occurred significantly more often at prairie dog towns in Cimarron County but not in the Panhandle. No single mustelid species showed a significant association with either prairie dog towns or non-prairie dog town habitats. Our results indicate that whereas prairie dog towns do attract some carnivore species, the presumption that prairie dogs are ""keystone species"" for so many organisms (especially threatened or endangered species) in the current plains ecosystem may not be as clear as previously thought.     

Laboratory fattening and dietary-fat effects on Meadow voles ( Microtus pennsylvanicus )

When removed from the field and maintained under laboratory conditions, meadow voles exhibited significant change in body composition. Voles increased body mass due primarily to large gains in lipid mass combined with small losses in fat-free mass. Lipid deposition amounts increased as dietary fat was increased, and animals demonstrated a leveling of body mass instead of continuous unregulated obesity. When dietary fat content was changed, lipid deposition or utilization responded directly. Thus, meadow voles regulate overall body mass and body composition (lipid and fat-free mass) at levels that correspond to dietary quality (fat) and abundance in the laboratory, and they deposit considerably more lipid than do animals in the field. Our experiments demonstrate that food quality has a substantial effect on the body composition of wild-caught animals maintained in the laboratory.     

基于分布式无线智能传感器网络的结构模态识别

利用美国伊利诺伊大学结构健康监测项目组研制的ISM400无线智能传感器,分别采用分布式和集中式数据采集方法,对一个简支层压板进行了振动测试试验.采用自然环境激励技术(NExT)和特征系统实现算法(ERA)相结合的一种时域联合算法,仅利用输出信号对结构模态参数进行识别,并将识别结果与有限元模型的计算结果进行了对比分析.根据分布式与集中式两种数据采集处理方法识别的振动频率和模态振型,与有限元数值模拟结果吻合较好,验证了基于分布式数据采集的无线智能传感器网络在结构模态识别中的可行性.在大型土木工程结构需要布置大量传感器时,分布式无线智能传感器网络因其高度集成化和节约电源等优点,比采用传统的集中式数据采集方法更加高效实用.     

Hymenaea protera sp.n. (Leguminosae,Caesalpinioideae) from Dominican amber has African affinities

Hymenaea protera is described from amber originating from La Toca mine in the Dominican Republic. The fossil species is characterized by the presence of reduced petals as well as distinctly clawed showy petals with cordate to reniform bases and a glabrous, verrucose ovary with long hirsute hairs at its base and along one margin. The fossil species most closely resembles the extantH. verrucosa Gaertner which occurs in East Africa and adjacent islands. These findings are interpreted as supporting a hypothesis that the genusHymenaea arose in the late Cretaceous on the combined South American-African continents and that Cretaceous and early Tertiary landmass movements were significant in determining the present amphi-Atlantic distribution of the genus. It is proposed that at least the majority, if not all, of the amber recovered from La Toca mine and other mines in the vicinity with similar-aged deposits originated fromH. protera.     

All together now: The circular organization in a university Hospital. Part II. Implementation

The first part of this two-part series described the initial impetus driving a university hospital's planned change project, the planning process itself, and the interventions that were identified to meet our goals. This article describes and discusses the interventions—the implementation of our version of Ackoff's circular organization and issues related to barriers, selected outcomes, the change process, evaluation, and the project's significance to nursing.     

ADVANCES IN DECISION ANALYSIS AND SYSTEMS ENGINEERING FOR MANAGING LARGE-SCALE ENTERPRISES IN A VOLATILE WORLD： INTEGRATING BENEFITS, OPPORTUNITIES, COSTS AND RISKS （BOCR） WITH THE BUSINESS MOTIVATION MODEL （BMM）

1. Introduction Recent advances in Information and Communication Technologies (ICT) have occurred in a number of areas includinginformation quality (Chutimaskul and Wangpipatwong 2004), strategy (Sha, Hung and Lin 2004) organization (Crowne 2004), technological change (Mitchell 2004), and utility1. Introduction Recent advances in Information and Communication Technologies (ICT) have occurred in a number of areas includinginformation quality (Chutimaskul and Wangpipatwong 2004), strateg…     

A new model of glucocorticoid-induced metanephric maldevelopment

Summary A new experimental model of glucocortocoid-induced tubular cyst formation has been developed in metanephric organ culture. The addition of cortisol (1.4×10^–5 M) to chemically defined serum-free culture medium produces cystic changes during in vitro nephrogenesis. The model isolates the role of glucocorticoids in experimental cyst formation.Acknowledgment. This work has been supported by Basil O'Connor Starter Research Grant No.5-349 from the March of Dimes Birth Defects Foundation.