Please cite this article in press as: Ripple, W.J., (2011), doi:10.1016/j.biocon.2011.11.005 The 1995/1996 reintroduction of gray wolves (Canis lupus) into Yellowstone National Park after a 70 year absence has allowed for studies of tri-trophic cascades involving wolves, elk (Cervus elaphus), and plant species such as aspen (Populus tremuloides), cottonwoods (Populus spp.), and willows (Salix s...

Spatial interactions between trees influence forest community succession. The objective of this study was to investigate how shifts in composition and proximity tree species affect stand development over time mixed systems. At six locations across the Fishlake National Forest, Utah, USA, stands where facilitation has been documented previously, tree-ring samples were collected from aspen subalp...

the understanding of the dynamic behavior of distillation columns has received considerable attention because distillation is one of the most widely used unit operations in chemical process industries. this paper reports a dynamic simulation study of the possible distillation columns sequences of dew pointing unit in the second phase of south pars gas refinery. in this unit, three columns are u...

The photoperiod is an important environmental signal for plants, and influences a wide range of physiological processes. For woody species in northern latitudes, cessation of growth is induced by short photoperiods. In many plant species, short photoperiods stop elongational growth after a few weeks. It is known that plant daylength detection is mediated by Phytochrome A (PHYA) in the woody hyb...

Although many species of bats select roost sites in large trees that are in open areas, intraspecific variation in roost-site selection may exist. We collected data on the roosting behaviour of little brown bats in the Cypress Hills, Saskatchewan, to determine the extent of intraspecific variation in roost-site selection. In addition, we examined the thermal microclimate of the tree-roosts sele...

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...

The Cu-Cl thermochemical cycle for hydrogen production was selected on the basis of its high efficiency and moderate temperature requirements. The modeling and simulation of Cu-Cl thermochemical cycle for hydrogen production is investigated in Aspen Plus. Since this cycle is a high energy-consuming process, the heat integration technique is implemented to recover the waste heat such that the pr...

In this work we use adjusted parameters obtained with Simulated Annealing and those from Dechema Collection [1] for the NRTL model, in order to analyze their effect in the design, optimization, and control of homogeneous azeotropic distillation columns. For the design of the azeotropic sequences we use short design methodologies [2, 3], while a multiobjective genetic algorithm with constraints ...

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...