High-resolution N-body Simulations of Galactic Cannibalism: The Magellanic Stream

Hierarchical clustering represents the favoured paradigm for galaxy formation throughout the Universe; due to its proximity, the Magellanic system offers one of the few opportunities for astrophysicists to decompose the full six-dimensional phase-space history of a satellite in the midst of being cannibalised by its host galaxy. The availability of improved observational data for the Magellanic Stream and parallel advances in computational power has led us to revisit the canonical tidal model describing the disruption of the Small Magellanic Cloud and the consequent formation of the Stream. We suggest improvements to the tidal model in light of these recent advances.Comment: 6 pages, 4 figures, LaTeX (gcdv.sty). Refereed contribution to the 5th Galactic Chemodynamics conference held in Swinburne, July 2003. Accepted for publication in PASA. Version with high resolution figures available at http://astronomy.swin.edu.au/staff/tconnors/publications.htm

International consensus (ICON) on treatment of Ménière's disease

Objective: To present the international consensus for recommendations for Ménière's disease (MD) treatment. Methods: Based on a literature review and report of 4 experts from 4 continents, the recommendations have been presented during the 21st IFOS congress in Paris, in June 2017 and are presented in this work. Results: The recommendation is to change the lifestyle, to use the vestibular rehabilitation in the intercritic period and to propose psychotherapy. As a conservative medical treatment of first line, the authors recommend to use diuretics and Betahistine or local pressure therapy. When medical treatment fails, the recommendation is to use a second line treatment, which consists in the intratympanic injection of steroids. Then as a third line treatment, depending on the hearing function, could be either the endolymphatic sac surgery (when hearing is worth being preserved) or the intratympanic injection of gentamicin (with higher risks of hearing loss). The very last option is the destructive surgical treatment labyrinthectomy, associated or not to cochlear implantation or vestibular nerve section (when hearing is worth being preserved), which is the most frequent option

Biological and physical oceanographic observations pertaining to the trawl fishery in a region of persistent coastal upwelling

An upwelling episode in the Point Sal region of the central California coast is examined by using data obtained by a data buoy. The episodes was interrupted by the abrupt abatement of the strong wind which promotes coastal upwelling. The mean hourly upwelling index is calculated to be higher than the 20 year mean monthly value. During 3 days of light wind commercial bottom trawl operations were possible. Shipboard estimates of chlorophyll content in surface waters during trawling show the high concentrations that are indicative of a rich biomass of phytoplankton, a result of the upwelling episode. Satellite imagery shows the extent of the upwelling water to be of the order of 100 km offshore; the result of many upwelling episodes. Shipboard echo sounder data show the presence of various delmersal species and of zooplakton; the latter graze on the phytoplankton in the upper euphotic layers. The fish catch data are recorded according to species for 2 days of trawling, and the catch per trawl hour is recorded

Conceptualizations of Nature and Scientific Literacy, Part I: Research Methodology

If we may paraphrase and adapt from feminist scholars, there are voices of people that need to be heard if scholars intend to have a valid understanding of people and their behavior. The feminist scholars were of course seeking ways of making women’s voices heard but the importance of their work exceeds gender issues. It is important for restoring the image of people as persons rather than as objects of research. As we have undertaken it, the foundational perspective of worldview research is that one must hear from students and science teachers about themselves. We thus suggest it is important for science educators to understand the fundamental, culturally based beliefs about the world that students and teachers bring to class; because, science education is successful only to the extent that science can find a niche in the cognitive and cultural milieus of students. The purpose of this article is to present an new interpretive methodology for exploring worldview presuppositions about the natural world through the language and ideas voluntarily expressed by science teachers and students. The methodology addresses the broad question, What is it that people think about nature or the natural world? The research objective of the methodology is to map the qualitatively different conceptualizations of nature held by people and thus to better understand the place science finds in those conceptualizations. The methodology is a modified naturalistic inquiry, interview technique. The audio taped interviews are semi-structured in that an interview involves elicitation devices designed to encourage a person to talk at length about nature. The findings are assertions based on concept maps and first person interpretive narratives derived from the interviews. The intention is to develop working hypotheses in the form of interpretive assertions through an emergent design. While the method described here is specifically about the essence of nature, similar methodology is used for investigating other worldview categories with respect to science understanding.

Student Reflections on a Study Abroad Course to the 2008 Summer Olympics in Beijing

The authors lead a study abroad trip to Beijing, China during the 2008 Summer Olympic Games. Included are reflections from the students who participated. Throughout the visit, students had the opportunity to complete learning outside of the traditional classroom setting. In addition, various challenges were faced and overcome which also constituted a learning experience and was the cause of reflection. The country of China and all of its historical landmarks had a great impression on these students, especially the day that was spent at the Great Wall. Finally, being able to be at the Olympic Games was a life-changing experience, from the Opening Ceremony to the events that were attended. In all, it was a thoroughly worthwhile adventure and one that we hope to replicate every two years

Expression of the coat protein genes of PNRSV and PDV in the synergistic disease peach stunt

Simultaneous infections of peach (Prunus persica Batsch L.) with the two ilarviruses, Prunus necrotic ringspot virus (PNRSV) and Prune dwarf virus (PDV), produce a synergistic disease referred to as “peach stunt”. Previous work showed significant differences in the expression of the coat protein (CP) genes. In the presence of PNRSV, an up to 17- fold reduction in the amount of (+) strand RNA 3 of PDV, as compared to similar trees infected with PDV alone, was observed. However, the presence of PDV had no effect on the concentration of (+) strand RNA 3 of PNRSV (Scott et al., 2001). This work re-examines and extends these observations using multiplex real-time PCR. Probes to both the plus and minus strands of the RNA 3 of each virus were designed and synthesized. The comparative CT method (ΔΔCT) was used for relative quantitation of gene expression. A reduction in the amount of (+) strand RNA 3 of PDV observed in the earlier work was not seen using real-time PCR. However, in a time course experiment with samples collected at 14-day intervals for 6 weeks, there was a substantial increase in the concentration of the (+) strand of RNA 3 of PDV after 14 days irrespective of whether the virus was present as a sole infecting agent or as a co-infection with PNRSV. At this same point in time there was a decrease in concentration of (+) of the RNA 3 of PNRSV. By the next sample date the concentrations of the (+) strand of RNA 3 of both viruses had returned to “normal”. The results are discussed in relation to the most extensively studied plant viral synergism synergism (PVY and PVX) and to known changes in concentration of PNRSV and PDV based on earlier observations made using ELISA. Keywords: Peach, Prunus necrotic ringspot virus, Prune dwarf virus, peach stunt disease, molecular interaction, Multiplex real-time PC

Assembly and force measurement with SPM-like probes in holographic optical tweezers

We report a high fidelity tomographic reconstruction of the quantum state of photon pairs generated by parametric down-conversion with orbital angular momentum (OAM) entanglement. Our tomography method allows us to estimate an upper and lower bound for the entanglement between the down-converted photons. We investigate the two-dimensional state subspace defined by the OAM states ±ℓ and superpositions thereof, with ℓ=1, 2, ..., 30. We find that the reconstructed density matrix, even for OAMs up to around ℓ=20, is close to that of a maximally entangled Bell state with a fidelity in the range between F=0.979 and F=0.814. This demonstrates that, although the single count-rate diminishes with increasing ℓ, entanglement persists in a large dimensional state space

Leaving Elementary School with a Sense of Order in Nature

Ninth graders in Arizona high schools have just left their elementary, general science education and are at the start of more specialized secondary science education. They are beginning a course of study that will form the foundation for tertiary education and employment after high school graduation. The research asked, Who are these kids entering high school science courses? The researchers noted that one of the key objectives of elementary education is to foster in children the concept that nature is inherently orderly and thus amenable to scientific investigation. Since the concept of order or disorder is fundamental in one’s perception of reality, the researchers reasoned that the qualitative worldview interviews on nature would be revealing of these concepts. The research led to this assertion: After nine years of schooling, ninth graders show no consistent understanding of the order in nature on which science is predicated. Instead, students often name drop school science topics such as the ozone layer, rain forests, or the big bang theory