SWECS tower dynamics analysis methods and results

Several different tower dynamics analysis methods and computer codes were used to determine the natural frequencies and mode shapes of both guyed and freestanding wind turbine towers. These analysis methods are described and the results for two types of towers, a guyed tower and a freestanding tower, are shown. The advantages and disadvantages in the use of and the accuracy of each method are also described

Symbiont 'bleaching' in planktic foraminifera during the Middle Eocene Climatic Optimum

Many genera of modern planktic foraminifera are adapted to nutrient-poor (oligotrophic) surface waters by hosting photosynthetic symbionts, but it is unknown how they will respond to future changes in ocean temperature and acidity. Here we show that ca. 40 Ma, some fossil photosymbiont-bearing planktic foraminifera were temporarily 'bleached' of their symbionts coincident with transient global warming during the Middle Eocene Climatic Optimum (MECO). At Ocean Drilling Program (ODP) Sites 748 and 1051 (Southern Ocean and mid-latitude North Atlantic, respectively), the typically positive relationship between the size of photosymbiont-bearing planktic foraminifer tests and their carbon isotope ratios (δ13C) was temporarily reduced for ∼100 k.y. during the peak of the MECO. At the same time, the typically photosymbiont-bearing planktic foraminifera Acarinina suffered transient reductions in test size and relative abundance, indicating ecological stress. The coincidence of minimum δ18O values and reduction in test size–δ13C gradients suggests a link between increased sea-surface temperatures and bleaching during the MECO, although changes in pH and nutrient availability may also have played a role. Our findings show that host-photosymbiont interactions are not constant through geological time, with implications for both the evolution of trophic strategies in marine plankton and the reliability of geochemical proxy records generated from symbiont-bearing planktic foraminifera

Hybrid meson decay from the lattice

We discuss the allowed decays of a hybrid meson in the heavy quark limit. We deduce that an important decay will be into a heavy quark non-hybrid state and a light quark meson, in other words, the de-excitation of an excited gluonic string by emission of a light quark-antiquark pair. We discuss the study of hadronic decays from the lattice in the heavy quark limit and apply this approach to explore the transitions from a spin-exotic hybrid to $\chi_b \eta$ and $\chi_b S$ where $S$ is a scalar meson. We obtain a signal for the transition emitting a scalar meson and we discuss the phenomenological implications.Comment: 18 pages, LATEX, 3 ps figure

Nitrogen Excretion from Beef Cattle for 6 Cover Crop Mixes as Estimated by a Nutritional Model

Excretion of nitrogen (N) from cattle within crop‐livestock systems is an important component of nutrient cycling, but measuring fecal and urinary N excretion in grazing cattle is a difficult and time consuming task. Nutritional models are available to estimate feed utilization and have been used to predict N excretion in grazing cattle. Using the Large Ruminant Nutrition Model, we predicted N losses from mature pregnant beef cows and growing beef heifers from compositional analysis of cover crop mixes grown in central South Dakota. All of the mixes used contained crude protein (CP) concentrations greater than cattle requirements. Estimates of both total fecal and urinary N excretion were greater for cows than heifers due to the greater BW and N intake of cows, however, the proportion of total N intake excreted in the feces was not predicted to differ between cattle maturities. Urinary excretion of N was predicted to be less for heifers, both when expressed as lb/d of N excreted or as a percentage of N intake. When accounting for potential stocking rate differences, it was predicted that slightly less urinary N excretion per acre could be expected by grazing younger cattle that utilize some N for growth compared to a mature animal

A Study of Labour Force Flows 1961-80. Quarterly Economic Commentary Special Article, May 1982

A Study of Labour Force Flows

Salmonella Typhimurium in the Australian egg industry: multidisciplinary approach to addressing the public health challenge and future directions

In Australia, numerous egg related human Salmonella Typhimurium outbreaks have prompted significant interest amongst public health authorities and the egg industry to jointly address this human health concern. Nationwide workshops on Salmonella and eggs were conducted in Australia for egg producers and regulatory authorities. State and National regulators representing Primary Production, Communicable Disease Control, Public Health and Food Safety and Food Standards Australia and New Zealand. All attendees participated in discussions aimed at evaluating current evidence based information, issues related to quality egg production and how to ensure safe eggs in the supply chain, identifying research gaps and practical recommendations. The perceptions from egg producers and regulatory authorities from various states were recorded during the workshops. We presented the issues discussed during the workshops including Salmonella in the farm environment, Salmonella penetration across egg shell, virulence in humans, food/egg handling in the supply chain and intervention strategies. We also discussed the perceptions from egg producers and regulators. Recommendations placed emphasis on future research needs, communication between industry and regulatory authorities and education of food handlers. Communication between regulators and industry is pivotal to control egg borne S. Typhimurium outbreaks and collaborative efforts are required to design effective and appropriate control strategies.Kapil K. Chousalkar, Margaret Sexton, Andrea McWhorter, Kylie Hewson, Glen Martin, Craig Shadbolt & Paul Goldsmit

Light hadron spectroscopy with O(a) improved dynamical fermions

We present the first results for the static quark potential and the light hadron spectrum using dynamical fermions at $\beta=5.2$ using an O(a) improved Wilson fermion action together with the standard Wilson plaquette action for the gauge part. Sea quark masses were chosen such that the pseudoscalar-vector mass ratio, m_PS/m_V$, varies from 0.86 to 0.67. Finite-size effects are studied by using three different volumes, 8^3\cdot 24, 12^3\cdot 24 and 16^3\cdot 24. Comparing our results to previous ones obtained using the quenched approximation, we find evidence for sea quark effects in quantities like the static quark potential and the vector-pseudoscalar hyperfine splitting.Comment: 38 pages, 14 Postscript figure, LaTe

Experimental analysis of movements by prairie rattlesnakes, Crotalus viridis , during hibernation

Prairie rattlesnakes from Colorado, USA, were subjected to two thermal treatments during hibernation. The control treatment was carried out in a surrogate den in St. Louis, MO, USA and followed the normal seasonal thermal regime. Experimental manipulations were carried out in a second den in St. Louis. These series of manipulations reversed or modified the thermal gradient normally expected in wild dens. Periodic observations of the snakes within the control and experimental dens provided corroborative data to support the hypothesis that entry to and exit from dens is regulated by a reversing thermal gradient within wild dens.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47740/1/442_2004_Article_BF00344649.pd