Summary of the Status of Harvest Mice, Cricetidae: Reithrodontomys, in Arkansas

Although four species of harvest mice, Reithrodoniomyx, are known to occur in Arkansas, the distributional status of the genus in the state is poorly understood. Recent museum specimens significantly extend the range of R. megalotix and R. fulvescens in the state. R. megalotis is shown to range south through Phillips Co. in eastern Arkansas, and R. fulvescens is shown to range throughout most of the state, now including most of the Mississippi Alluvial Plain. A new specimen of R. humulis from Delaware Co., Oklahoma, suggests that this species probably ranges throughout northwestern Arkansas. R montanus remains known only from Washington Co. in northwestern Arkansas

Speech Communication

Contains three reports on research facilities and systems.U. S. Air Force Cambridge Research Laboratories, Office of Aerospace Research, under Contract F19628-69-C-0044National Institutes of Health (Grant 2 ROl NB-04332-06

A principled approach to the measurement of situation awareness in commercial aviation

The issue of how to support situation awareness among crews of modern commercial aircraft is becoming especially important with the introduction of automation in the form of sophisticated flight management computers and expert systems designed to assist the crew. In this paper, cognitive theories are discussed that have relevance for the definition and measurement of situation awareness. These theories suggest that comprehension of the flow of events is an active process that is limited by the modularity of attention and memory constraints, but can be enhanced by expert knowledge and strategies. Three implications of this perspective for assessing and improving situation awareness are considered: (1) Scenario variations are proposed that tax awareness by placing demands on attention; (2) Experimental tasks and probes are described for assessing the cognitive processes that underlie situation awareness; and (3) The use of computer-based human performance models to augment the measures of situation awareness derived from performance data is explored. Finally, two potential example applications of the proposed assessment techniques are described, one concerning spatial awareness using wide field of view displays and the other emphasizing fault management in aircraft systems

Redox reactions with empirical potentials: Atomistic battery discharge simulations

Batteries are pivotal components in overcoming some of today's greatest technological challenges. Yet to date there is no self-consistent atomistic description of a complete battery. We take first steps toward modeling of a battery as a whole microscopically. Our focus lies on phenomena occurring at the electrode-electrolyte interface which are not easily studied with other methods. We use the redox split-charge equilibration (redoxSQE) method that assigns a discrete ionization state to each atom. Along with exchanging partial charges across bonds, atoms can swap integer charges. With redoxSQE we study the discharge behavior of a nano-battery, and demonstrate that this reproduces the generic properties of a macroscopic battery qualitatively. Examples are the dependence of the battery's capacity on temperature and discharge rate, as well as performance degradation upon recharge.Comment: 14 pages, 10 figure

A search for CO+ in planetary nebulae

We have carried out a systematic search for the molecular ion CO+ in a sample of 8 protoplanetary and planetary nebulae in order to determine the origin of the unexpectedly strong HCO+ emission previously detected in these sources. An understanding of the HCO+ chemistry may provide direct clues to the physical and chemical evolution of planetary nebulae. We find that the integrated intensity of the CO+ line may be correlated with that of HCO+, suggesting that the reaction of CO+ with molecular hydrogen may be an important formation route for HCO+ in these planetary nebulae.Comment: 6 pages, 4 figures, accepted for publication in MNRA

Solid state television camera system Patent

Solid state television camera system consisting of monolithic semiconductor mosaic sensor and molecular digital readout system

Speech Communication

Contains reports on three research projects.U. S. Air Force Cambridge Research Laboratories under Contract F19628-69-C-0044National Institutes of Health (Grant 5 RO1 NS04332-09)M.I.T. Lincoln Laboratory Purchase Order CC-57

Speech Communication

Contains reports on three research projects.National Institutes of Health (Grant 5 RO1 NS04332-13)National Institutes of Health (Grant 1 T32 NS07040-01)Joint Services Electronics Program (Contract DAAB07-75-C-1346

Speech Communication

Contains reports on two research projects.U.S. Navy Office of Naval Research (Contract N00014-67-A-0204-0064)National Institutes of Health (Grant 5 ROl NS04332-09)National Science Foundation (Grant GK-31353

Rarity in Astragalus: a California Perspective

Astragalus (Fabaceae), the largest genus of plants in the world with an estimated 3270 species, is known for large numbers of rare endemic species. An inventory of patterns of climatic, topographic, and edaphic diversity of Astragalus taxa in California (98 native species and 144 named taxa) provides a means to understand the occurrence of rarity in relation to climatic equitability and regional species richness of congeneric taxa. Most taxa in the genus have relatively small ranges of distribution, with 50% restricted geographically to a single Jepson Bioregion. The California Native Plant Society lists 51 Astragalus taxa (35% of the native Astragalus taxa) as rare, threatened, or endangered (RTE). Climate characteristics of geographic regions such as rainfall and temperature extremes show no obvious relationship to species richness or the proportion of listed taxa. Species richness is highest in the arid Great Basin (35 species and 53 taxa) combining both its components, followed by 29 species and 39 taxa in the Sierra Nevada East region that includes the White and Inyo Mountains. The Mojave Desert is also high in diversity with 32 species and 39 taxa, but in contrast the Sonoran Desert region is low with only 12 species and 14 taxa. Despite ranking highest in the number of Astragalus taxa present, the Great Basin regions are low in their proportion of RTE taxa (17%) compared to the South Coast Region (39.5%) and Mojave Desert (32%). Strong edaphic specialization is associated with the majority but not all RTE taxa. While no single ecophysiological adaptation can explain this pattern, it is significant that Astragalus taxa have the potential ability to develop symbiotic nitrogen fixation, and this trait is key to success in soils not conducive to growth of many potential competitors. Land use changes, alien grass invasion and grazing, among other threats, are increasing fragmentation of habitats for many rare taxa with consequent impacts on gene flow. The continued survival of rare and locally endemic taxa will require improved knowledge of their individual demographic traits and long-term population dynamics