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

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

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

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

Regular Expression Matching and Operational Semantics

Many programming languages and tools, ranging from grep to the Java String library, contain regular expression matchers. Rather than first translating a regular expression into a deterministic finite automaton, such implementations typically match the regular expression on the fly. Thus they can be seen as virtual machines interpreting the regular expression much as if it were a program with some non-deterministic constructs such as the Kleene star. We formalize this implementation technique for regular expression matching using operational semantics. Specifically, we derive a series of abstract machines, moving from the abstract definition of matching to increasingly realistic machines. First a continuation is added to the operational semantics to describe what remains to be matched after the current expression. Next, we represent the expression as a data structure using pointers, which enables redundant searches to be eliminated via testing for pointer equality. From there, we arrive both at Thompson's lockstep construction and a machine that performs some operations in parallel, suitable for implementation on a large number of cores, such as a GPU. We formalize the parallel machine using process algebra and report some preliminary experiments with an implementation on a graphics processor using CUDA.Comment: In Proceedings SOS 2011, arXiv:1108.279

Role of Asian summer monsoon subsystems in the inter-hemispheric progression of deglaciation

The responses of Asian monsoon subsystems to both hemispheric climate forcing and external orbital forcing are currently issues of vigorous debate. The Indian summer monsoon is the dominant monsoon subsystem in terms of energy flux, constituting one of Earth’s most dynamic expressions of ocean–atmosphere interactions. Yet, the Indian summer monsoon is grossly under-represented in Asian monsoon palaeoclimate records. Here, we present high-resolution records of Indian summer monsoon- induced rainfall and fluvial runoff recovered in a sediment core from the Bay of Bengal across Termination II, 139–127 thousand years ago, including coupled measurements of the oxygen isotopic composition and Mg/Ca, Mn/Ca, Nd/Ca and U/Ca ratios in surface-ocean-dwelling foraminifera. Our data reveal a millennial-scale transient strengthening of the Asian monsoon that punctuates Termination II associated with an oscillation of the bipolar seesaw. The progression of deglacial warming across Termination II emerges first in the Southern Hemisphere, then the tropics in tandem with Indian summer monsoon strengthening, and finally the Northern Hemisphere. We therefore suggest that the Indian summer monsoon was a conduit for conveying Southern Hemisphere latent heat northwards, thereby promoting subsequent Northern Hemisphere deglaciation

Instability in the Molecular Dynamics Step of Hybrid Monte Carlo in Dynamical Fermion Lattice QCD Simulations

We investigate instability and reversibility within Hybrid Monte Carlo simulations using a non-perturbatively improved Wilson action. We demonstrate the onset of instability as tolerance parameters and molecular dynamics step sizes are varied. We compare these findings with theoretical expectations and present limits on simulation parameters within which a stable and reversible algorithm is obtained for physically relevant simulations. Results of optimisation experiments with respect to tolerance prarameters are also presented

Droplets Transport in a Microfluidic Chip for In Vitro Compartmentalisation

In vitro compartmentalisation is an emerging technology for protein evolution and selection. In this presentation, we will report the development of a microdrop-based microfluidic platform for in vitro enzyme evolution and selection applications. A microfluidic chip has been developed and fabricated using the standard photolithography method in conjunction with electroplating and hot embossing techniques. A cross channel geometry was used to focus liquid flows for droplet generation. To realize on-chip compartmentalised bio-reactions, two droplet generators were fabricated on the same chip. Experiments have been carried out to measure droplet size, generation rate and speed using a photographic technique. Droplet size was found to be decreasing with increasing focusing oil flow rate for a given aqueous phase flow rate. When two droplet generators are used in the same chip, the droplets may be generated asynchronously due to different flow conditions. If the droplets were significantly smaller than channel size, the faster moving droplets could pass the slower moving droplets with little coalescence. If the droplets were of the channel size, the faster moving droplets would break or fuse with the slow droplets. To achieve high rate of droplet fusion, active control should be in place for synchronous generation and fusion

Late Maastrichtian carbon isotope stratigraphy and cyclostratigraphy of the Newfoundland Margin (Site U1403, IODP Expedition 342)

Earth’s climate during the Maastrichtian (latest Cretaceous) was punctuated by brief warming and cooling episodes, accompanied by perturbations of the global carbon cycle. Superimposed on a long-term cooling trend, the middle Maastrichtian is characterized by deep-sea warming and relatively high values of stable carbon-isotope ratios, followed by strong climatic variability towards the end of the Cretaceous. A lack of knowledge on the timing of climatic change inhibits our understanding of underlying causal mechanisms. We present an integrated stratigraphy from Integrated Ocean Drilling Program (IODP) Site U1403, providing an expanded deep ocean record from the North Atlantic (Expedition 342, Newfoundland Margin). Distinct sedimentary cyclicity suggests that orbital forcing played a major role in depositional processes, which is confirmed by statistical analyses of high resolution elemental data obtained by X-ray fluorescence (XRF) core scanning. Astronomical calibration reveals that the investigated interval encompasses seven 405-kyr cycles (Ma4051 to Ma4057) and spans the 2.8 Myr directly preceding the Cretaceous/Paleocene (K/Pg) boundary. A high-resolution carbon-isotope record from bulk carbonates allows us to identify global trends in the late Maastrichtian carbon cycle. Low-amplitude variations (up to 0.4‰) in carbon isotopes at Site U1403 match similar scale variability in records from Tethyan and Pacific open-ocean sites. Comparison between Site U1403 and the hemipelagic restricted basin of the Zumaia section (northern Spain), with its own well-established independent cyclostratigraphic framework, is more complex. Whereas the pre-K/Pg oscillations and the negative values of the Mid-Maastrichtian Event (MME) can be readily discerned in both the Zumaia and U1403 records, patterns diverge during a ~ 1 Myr period in the late Maastrichtian (67.8–66.8 Ma), with Site U1403 more reliably reflecting global carbon cycling. Our new carbon isotope record and cyclostratigraphy offer promise for Site U1403 to serve as a future reference section for high-resolution studies of late Maastrichtian paleoclimatic change