Oregon State University

About: Oregon State University is a education organization based out in Corvallis, Oregon, United States. It is known for research contribution in the topics: Population & Climate change. The organization has 28192 authors who have published 64044 publications receiving 2634108 citations. The organization is also known as: Oregon Agricultural College & OSU.

Distance learning applied to control engineering laboratories

Abstract: Distance learning is an emerging paradigm where students, teachers, and equipment may be at different geographic locations. At the College of Engineering of Oregon State University, we have developed and demonstrated an innovative real-time remote-access control engineering teaching laboratory. Our remote laboratory uses the Internet to provide complete access to the usual laboratory facilities. In addition, remote power control, network reliability, and safety features are integrated into our experimental hardware and software design. Remotely located students are able to develop, compile, debug, and run controllers in real time on the experiments in our laboratory. Students can watch the experiment in real time from a remote workstation, hear the sounds in the laboratory, and interact with other laboratory users. Students can effectively use the laboratory from anywhere on the Internet.

Unicellular Cyanobacterial Distributions Broaden the Oceanic N2 Fixation Domain

Abstract: Nitrogen (N 2 )–fixing microorganisms (diazotrophs) are an important source of biologically available fixed N in terrestrial and aquatic ecosystems and control the productivity of oligotrophic ocean ecosystems. We found that two major groups of unicellular N 2 -fixing cyanobacteria (UCYN) have distinct spatial distributions that differ from those of Trichodesmium , the N 2 -fixing cyanobacterium previously considered to be the most important contributor to open-ocean N 2 fixation. The distributions and activity of the two UCYN groups were separated as a function of depth, temperature, and water column density structure along an 8000-kilometer transect in the South Pacific Ocean. UCYN group A can be found at high abundances at substantially higher latitudes and deeper in subsurface ocean waters than Trichodesmium . These findings have implications for the geographic extent and magnitude of basin-scale oceanic N 2 fixation rates.

Safety and efficiency conflicts in hydraulic architecture: scaling from tissues to trees

Abstract: Tree hydraulic architecture exhibits patterns that propagate from tissue to tree scales. A challenge is to make sense of these patterns in terms of trade-offs and adaptations. The universal trend for conduits per area to decrease with increasing conduit diameter below the theoretical packing limit may reflect the compromise between maximizing the area for conduction versus mechanical support and storage. Variation in conduit diameter may have two complementary influences: one being compromises between efficiency and safety and the other being that conduit tapering within a tree maximizes conductance per growth investment. Area-preserving branching may be a mechanical constraint, preventing otherwise more efficient top-heavy trees. In combination, these trends beget another: trees have more, narrower conduits moving from trunks to terminal branches. This pattern: (1) increases the efficiency of tree water conduction; (2) minimizes (but does not eliminate) any hydraulic limitation on the productivity or tissue growth with tree height; and (3) is consistent with the scaling of tree conductance and sap flow with size. We find no hydraulic reason why tree height should scale with a basal diameter to the two-thirds power as recently claimed; it is probably another mechanical constraint as originally proposed. The buffering effect of capacitance on the magnitude of transpiration-induced xylem tension appears to be coupled to cavitation resistance, possibly alleviating safety versus efficiency trade-offs.

Novel bacterial and archaeal lineages from an in situ growth chamber deployed at a Mid-Atlantic Ridge hydrothermal vent.

Abstract: The phylogenetic diversity was determined for a microbial community obtained from an in situ growth chamber placed on a deep-sea hydrothermal vent on the Mid-Atlantic Ridge (23°22* N, 44°57* W). The chamber was deployed for 5 days, and the temperature within the chamber gradually decreased from 70 to 20°C. Upon retrieval of the chamber, the DNA was extracted and the small-subunit rRNA genes (16S rDNA) were amplified by PCR using primers specific for the Archaea or Bacteria domain and cloned. Unique rDNA sequences were identified by restriction fragment length polymorphisms, and 38 different archaeal and bacterial phylotypes were identified from the 85 clones screened. The majority of the archaeal sequences were affiliated with the Thermococcales (71%) and Archaeoglobales (22%) orders. A sequence belonging to the Thermoplasmales confirms that thermoacidophiles may have escaped enrichment culturing attempts of deep-sea hydrothermal vent samples. Additional sequences that represented deeply rooted lineages in the low-temperature eurarchaeal (marine group II) and crenarchaeal clades were obtained. The majority of the bacterial sequences obtained were restricted to the Aquificales (18%), the « subclass of the Proteobacteria («-Proteobacteria) (40%), and the genus Desulfurobacterium (25%). Most of the clones (28%) were confined to a monophyletic clade within the «-Proteobacteria with no known close relatives. The prevalence of clones related to thermophilic microbes that use hydrogen as an electron donor and sulfur compounds (S 0 ,S O 4, thiosulfate) indicates the importance of hydrogen oxidation and sulfur metabolism at deep-sea hydrothermal vents. The presence of sequences that are related to sequences from hyperthermophiles, moderate thermophiles, and mesophiles suggests that the diversity obtained from this analysis may reflect the microbial succession that occurred in response to the shift in temperature and possible associated changes in the chemistry of the hydrothermal fluid.