From bacteria to multicellular animals, most organisms exhibit declines in survivorship or reproductive performance with increasing age ("senescence"). Evidence for senescence in clonal plants, however, is scant. During asexual growth, we expect that somatic mutations, which negatively impact sexual fitness, should accumulate and contribute to senescence, especially among long-lived clonal plan...

BACKGROUND Previous studies have shown that plants often have species-specific effects on soil properties. In high elevation forests in the Southern Rocky Mountains, North America, areas that are dominated by a single tree species are often adjacent to areas dominated by another tree species. Here, we assessed soil properties beneath adjacent stands of trembling aspen, lodgepole pine, and Engel...

STUDY DESIGN Randomized controlled trial. OBJECTIVE The aim of the study was to compare and contrast the restrictiveness and tissue-interface pressure (TIP) characteristics of 2 standard and 2 adjustable cervical collars. SUMMARY OF BACKGROUND DATA This study compared the restrictiveness and TIP of 4 commercially available cervical collars (2 standard and 2 adjustable). Adjustable collars o...

Concentrations of cellulose, lignin and nutrients in the stemwood of four clones of 7-year-old hybrid aspen (Populus tremula L. x P. tremuloides Michx.) were studied on 50 permanent experimental plots established for the afforestation of abandoned agricultural lands in Estonia. Quantitative evaluation of hybrid aspen chemical components indicated a relatively high cellulose and low acid-insolub...

Increasing concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have the potential to affect tree physiology and structure, and hence forest feedbacks on climate. Here, we investigated how elevated concentrations of CO2 (+45%) and O3 (+35%), alone and in combination, affected conductance for mass transfer at the leaf and canopy levels in pure aspen (Populus tremuloides...

A number of successful applications of automated planning and scheduling applications to spacecraft operations have recently been reported in the literature. However, these applications have been oneof-a-kind applications that required a substantial amount of development effort. In this paper, we describe ASPEN, a modular, reconfigurable application framework which is capable of supporting a wi...

Researchers from a number of disciplines have long sought the ability to estimate the functional attributes of plant canopies, such as photosynthetic capacity, using remotely sensed data. To date, however, this goal has not been fully realized. In this study, fresh-leaf reflectance spectroscopy (λ=450-2500 nm) and a partial least-squares regression (PLSR) analysis were used to estimate key dete...

Methyl Tert-butyl Ether (MTBE) is an important chemical used as an octane booster in gasoline to replace tetra ethyl lead. Maximum production of the MTBE can be achieved using reactive distillation (RD) process at the optimum operating conditions and column configuration. However, optimizing the column configuration such as tray or catalyst location is experimentally expensive. Therefore, a rel...