150 research outputs found
Plant Manage
ABSTRACT We examined the impacts of mechanical shredding (i.e., shredding plants and leaving biomass in the system) of the water chestnut ( Trapa natans ) on water quality and nutrient mobilization in a control and experimental site in Lake Champlain (Vermont-New York). A 1-ha plot was mechanically shredded within 1 h on 26 July, 1999. Broken plant material was initially concentrated on the lake surface of the experimental station after shredding, and was noticeable on the lake surface for 19 d. Over a two week period after shredding, concentrations of total nitrogen (N) and phosphorus (P), and soluble reactive P increased in the lower water column of the experimental station, coinciding with decomposition of water chestnut. Sediments in the control and experimental stations exhibited very low rates of N and P release and could not account for increases in nutrient concentrations in the water column after mechanical shredding. Shredded plant material deployed in mesh bags at the experimental station lost ~ 70% of their total mass, and 42% N and 70% P within 14 d, indicating substantial nutrient mobilization via autolysis and decomposition. Chlorophyll a concentrations increased to 35 g/L at the experimental station on day 7 after shredding, compared to a concentration of 4 g/L at the control station, suggesting uptake of mobilized nutrients by phytoplankton. Disruption of the surface canopy of water chestnut by shredding was associated with marked increases in turbidity and dissolved oxygen, suggesting increased mixing at the experimental site
Predicting the effect of climate change on temperate shallow lakes with the ecosystem model PCLake
Changes in phosphorus content of two aquatic macrophytes according to water velocity, trophic status and time period in hardwater streams
DAAM is required for thin filament formation and Sarcomerogenesis during muscle development in Drosophila.
During muscle development, myosin and actin containing filaments assemble into the highly organized sarcomeric structure critical for muscle function. Although sarcomerogenesis clearly involves the de novo formation of actin filaments, this process remained poorly understood. Here we show that mouse and Drosophila members of the DAAM formin family are sarcomere-associated actin assembly factors enriched at the Z-disc and M-band. Analysis of dDAAM mutants revealed a pivotal role in myofibrillogenesis of larval somatic muscles, indirect flight muscles and the heart. We found that loss of dDAAM function results in multiple defects in sarcomere development including thin and thick filament disorganization, Z-disc and M-band formation, and a near complete absence of the myofibrillar lattice. Collectively, our data suggest that dDAAM is required for the initial assembly of thin filaments, and subsequently it promotes filament elongation by assembling short actin polymers that anneal to the pointed end of the growing filaments, and by antagonizing the capping protein Tropomodulin
Institutional investors and corporate governance
We provide a comprehensive overview of the role of institutional investors in corporate governance with three main components. First, we establish new stylized facts documenting the evolution and importance of institutional ownership. Second, we provide a detailed characterization of key aspects of the legal and regulatory setting within which institutional investors govern portfolio firms. Third, we synthesize the evolving response of the recent theoretical and empirical academic literature in finance to the emergence of institutional investors in corporate governance. We highlight how the defining aspect of institutional investors – the fact that they are financial intermediaries – differentiates them in their governance role from standard principal blockholders. Further, not all institutional investors are identical, and we pay close attention to heterogeneity amongst institutional investors as blockholders
Spatial pattern of a fish assemblage in a seasonal tropical wetland: effects of habitat, herbaceous plant biomass, water depth, and distance from species sources
The influence of Ceratophyllum demersum L. and Stratiotes aloides L. on richness and diversity of aquatic vegetation in the lakes of mid-eastern Poland
Patterns in fish species composition and assemblage structure in the upper Salado River lakes, Pampa Plain, Argentina
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