Desynchronization of pulse-coupled oscillators with delayed excitatory coupling

Collective behavior of pulse-coupled oscillators has been investigated widely. As an example of pulse-coupled networks, fireflies display many kinds of flashing patterns. Mirollo and Strogatz (1990) proposed a pulse-coupled oscillator model to explain the synchronization of South East Asian fireflies ({\itshape Pteroptyx malaccae}). However, transmission delays were not considered in their model. In fact, the presence of transmission delays can lead to desychronization. In this paper, pulse-coupled oscillator networks with delayed excitatory coupling are studied. Our main result is that under reasonable assumptions, pulse-coupled oscillator networks with delayed excitatory coupling can not achieve complete synchronization, which can explain why another species of fireflies ({\itshape Photinus pyralis}) rarely synchronizes flashing. Finally, two numerical simulations are given. In the first simulation, we illustrate that even if all the initial phases are very close to each other, there could still be big variations in the times to process the pulses in the pipeline. It implies that asymptotical synchronization typically also cannot be achieved. In the second simulation, we exhibit a phenomenon of clustering synchronization

A diffusion Monte Carlo study of small para-Hydrogen clusters

Ground state energies and chemical potentials of parahydrogen clusters are calculated from 3 to 40 molecules using the diffusion Monte Carlo technique with two different pH2-pH2 interactions. This calculation improves a previous one by the inclusion of three-body correlations in the importance sampling, by the time step adjustement and by a better estimation of the statistical errors. Apart from the cluster with 13 molecules, no other magic clusters are predicted, in contrast with path integral Monte Carlo results

The development of a cislunar space infrastructure

The primary objective of this Advanced Mission Design Program is to define the general characteristics and phased evolution of a near-Earth space infrastructure. The envisioned foundation includes a permanently manned, self-sustaining base on the lunar surface, a space station at the Libration Point between earth and the moon (L1), and a transportation system that anchors these elements to the Low Earth Orbit (LEO) station. The implementation of this conceptual design was carried out with the idea that the infrastructure is an important step in a larger plan to expand man's capabilities in space science and technology. Such expansion depends on low cost, reliable, and frequent access to space for those who wish to use the multiple benefits of this environment. The presence of a cislunar space infrastructure would greatly facilitate the staging of future planetary missions, as well as the full exploration of the lunar potential for science and industry. The rationale for, and a proposed detailed scenario in support of, the cislunar space infrastructure are discussed

On-farm demonstrations of low-input methods for establishing legumes in central Queensland

In 2010 a three year Meat and Livestock Australia funded Producer Demonstration Site (PDS) was established to demonstrate low-input sowing strategies for achieving legume establishment in buffel grass (Pennisetum ciliare) pastures in central Queensland. Butterfly pea (Clitoria ternatea), burgundy bean (Macroptillium bracteatum) and siratro (Macroptillium atropurpureum cv. siratro and cv. Aztec atro) were sown by broadcast, direct drill and crocodile seeder methods. Intensive herd impact applied immediately post sowing was trialled to determine if seed germination and establishment would benefit from animal induced soil disturbance. Treatments with soil disturbance at sowing (direct drill and crocodile seeder) recorded higher first year legume numbers than broadcasting. Despite excellent rainfall in the first two years of the trial, strong population declines across all treatments were recorded in subsequent years, with similar plant populations per hectare recorded between treatments at the conclusion of the trial. The results from the application of herd impact were inconclusive. Siratro was the only species to persist within the buffel grass dominated pastures. This trial demonstrated that low-input sowing methods with little or no removal of grass competition achieved poor plant populations. Industry needs to adopt longer fallow management for moisture storage and control of grass when establishing legumes into existing grass pastures

Documentation of the data analysis system for the gamma ray monitor aboard OSO-H

The programming system is presented which was developed to prepare the data from the gamma ray monitor on OSO-7 for scientific analysis. The detector, data, and objectives are described in detail. Programs presented include; FEEDER, PASS-1, CAL1, CAL2, PASS-3, Van Allen Belt Predict Program, Computation Center Plot Routine, and Response Function Programs

A Multi-signal Variant for the GPU-based Parallelization of Growing Self-Organizing Networks

Among the many possible approaches for the parallelization of self-organizing networks, and in particular of growing self-organizing networks, perhaps the most common one is producing an optimized, parallel implementation of the standard sequential algorithms reported in the literature. In this paper we explore an alternative approach, based on a new algorithm variant specifically designed to match the features of the large-scale, fine-grained parallelism of GPUs, in which multiple input signals are processed at once. Comparative tests have been performed, using both parallel and sequential implementations of the new algorithm variant, in particular for a growing self-organizing network that reconstructs surfaces from point clouds. The experimental results show that this approach allows harnessing in a more effective way the intrinsic parallelism that the self-organizing networks algorithms seem intuitively to suggest, obtaining better performances even with networks of smaller size.Comment: 17 page

Electromagnetic Transition Strengths in Heavy Nuclei

We calculate reduced B(E2) and B(M1) electromagnetic transition strengths within and between K-bands in support of a recently proposed model for the structure of heavy nuclei. Previously, only spectra and a rough indication of the largest B(E2) strengths were reported. The present more detailed calculations should aid the experimental identification of the predicted $0^+$, $1^+$ and $2^+$ bands and, in particular, act to confirm or refute the suggestion that the model $0^+$ and $2^+$ bands correspond to the well known and widespread beta and gamma bands. Furthermore they pinpoint transitions which can indicate the presence of a so far elusive $1^+$ band by feeding relatively strongly into or out of it. Some of these transitions may already have been measured in $^{230}$Th, $^{232}$Th and $^{238}$U.Comment: 10 pages, 1 Figure, submitted to Physical Review