Calcium Pyrophosphate Crystal Deposition: The Effect of Soluble Iron in a Kinetic Study Using a Gelatin Matrix Model

The kinetics of calcium pyrophosphate dihydrate (CPPD) crystal growth was studied by allowing calcium and pyrophosphate (PPi-4) ions to diffuse through a denatured collagen matrix (biological grade gelatin) in the presence of either ferric or ferrous ions. Ferric and, to some extent, ferrous ions blocked the migration of the PPi-4 diffusion gradient. This retardation in the [PPi-4] gradient led to numerous changes in the patterns of CPPD crystal formation. At the initial stages of crystal growth, the iron ions induced more crystal growth compared to control. At later incubation times, ferrous and ferric ions enhanced crystal growth at the expense of crystal nucleation. The presence of both ferrous and ferric ions resulted in the more rapid formation of the two crystals observed in vivo, triclinic CPPD and monoclinic CPPD. Further, both ferrous and ferric ions also reduced the solubility of the crystalline material in the broad diffuse band which formed when the Ca+2 and PPi-4 gradients first met. In this system, the presence of either ferrous or ferric ions increased the amount of hydroxyproline included in the crystalline precipitates. Iron was also incorporated into the crystals, particularly into the triclinic CPPD and monoclinic CPPD crystals

Calcium Pyrophosphate Crystal Deposition: The Effect of Monosodium Urate and Apatite Crystals in a Kinetic Study Using a Gelatin Matrix Model

The kinetics of calcium pyrophosphate dihydrate (CPPD) crystal growth was studied by allowing calcium and pyrophosphate (PPi-4) ions to diffuse through a denatured collagen matrix (biological grade gelatin) in the presence of either monosodium urate monohydrate (MSU) or hydroxyapatite (HA) crystals. In this in vitro model system, MSU crystals significantly altered the kinetics of PPi-4 ionic diffusion through the gelatin matrix by allowing the [PPi-4] gradient to fall off much more rapidly, suggesting an increased level of scavenging of PPi-4 ions into crystalline materials. Even more significantly, the presence of MSU crystals markedly influenced the crystal growth morphology of triclinic CPPD, producing that observed in vivo. A large number of epitaxially dimensional matches between MSU and triclinic (t) and monoclinic (m) CPPD were identified, suggesting that MSU crystals can epitaxially induce CPPD crystal growth. This finding supports the hypothesis that the association of urate gout and CPPD crystal deposition disease is based on the nucleating potential of MSU crystals for CPPD crystal growth. In contrast, the HA crystal structure did not appear to serve as a nucleating agent for CPPD crystals. However, HA crystals did serve as effective traps for PPi-4 ions and their presence led to more stable CPPD crystal growth

Calcium Pyrophosphate Crystal Deposition: A Kinetic Study Using a Type I Collagen Gel Model

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is characterized by deposits of triclinic (t) and monoclinic (m) CPPD crystals in articular and fibrocartilage. Many investigators have attempted to model CPPD crystal growth using both solution and a variety of gel systems. We have investigated the effect of type I collagen fibrils on CPPD crystal nucleation and growth using an ionic diffusion model. Collagen was isolated from porcine menisci using a pepsin solubilization procedure and gelled in three layers, with one containing 10 mM pyrophosphate (PPi) plus physiologic ions, the middle containing only the ions, while the third contained 25 mM Ca plus physiologic ions. Initially, amorphorous calcium pyrophosphate formed at the Ca-PPi interface. Monoclinic CPPD crystallized in 6 weeks when the [Ca] was between 2 and 3 mM and the [PPi] was between 50 and 75 μM. At 13 weeks, t-CPPD formed when the [Ca] was also between 2 and 3 mM, but the PPi was less than 25 μM. One of the most striking differences between this system and all previous solution and gel model systems is the total absence of orthorhombic calcium pyrophosphate tetrahydrate (o-CPPT) from the gels made of collagen fibrils in near native conformation. Further, crystals of t-CPPD appear as large single crystals with the classic prismatic growth habit observed in vivo, and crystals of m-CPPD also evidence the in vivo rod habit. In contrast, the crystal growth habits of t-CPPD, m-CPPD, and o-CPPT grown in all of the other model systems never matched that observed in vivo. When compared to the previous studies, these results, particularly the crystal growth habit data, suggest that the native collagen fibrils themselves can nucleate CPPD crystal formation

Detection Strategies for Extreme Mass Ratio Inspirals

The capture of compact stellar remnants by galactic black holes provides a unique laboratory for exploring the near horizon geometry of the Kerr spacetime, or possible departures from general relativity if the central cores prove not to be black holes. The gravitational radiation produced by these Extreme Mass Ratio Inspirals (EMRIs) encodes a detailed map of the black hole geometry, and the detection and characterization of these signals is a major scientific goal for the LISA mission. The waveforms produced are very complex, and the signals need to be coherently tracked for hundreds to thousands of cycles to produce a detection, making EMRI signals one of the most challenging data analysis problems in all of gravitational wave astronomy. Estimates for the number of templates required to perform an exhaustive grid-based matched-filter search for these signals are astronomically large, and far out of reach of current computational resources. Here I describe an alternative approach that employs a hybrid between Genetic Algorithms and Markov Chain Monte Carlo techniques, along with several time saving techniques for computing the likelihood function. This approach has proven effective at the blind extraction of relatively weak EMRI signals from simulated LISA data sets.Comment: 10 pages, 4 figures, Updated for LISA 8 Symposium Proceeding

Qatar-2: A K dwarf orbited by a transiting hot Jupiter and a more massive companion in an outer orbit

We report the discovery and initial characterization of Qatar-2b, a hot Jupiter transiting a V = 13.3 mag K dwarf in a circular orbit with a short period, P_ b = 1.34 days. The mass and radius of Qatar-2b are M_p = 2.49 M_j and R_p = 1.14 R_j, respectively. Radial-velocity monitoring of Qatar-2 over a span of 153 days revealed the presence of a second companion in an outer orbit. The Systemic Console yielded plausible orbits for the outer companion, with periods on the order of a year and a companion mass of at least several M_j. Thus Qatar-2 joins the short but growing list of systems with a transiting hot Jupiter and an outer companion with a much longer period. This system architecture is in sharp contrast to that found by Kepler for multi-transiting systems, which are dominated by objects smaller than Neptune, usually with tightly spaced orbits that must be nearly coplanar

The Mock LISA Data Challenges: from Challenge 3 to Challenge 4

The Mock LISA Data Challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of one or more datasets containing simulated instrument noise and gravitational waves from sources of undisclosed parameters. Participants analyze the datasets and report best-fit solutions for the source parameters. Here we present the results of the third challenge, issued in Apr 2008, which demonstrated the positive recovery of signals from chirping Galactic binaries, from spinning supermassive--black-hole binaries (with optimal SNRs between ~ 10 and 2000), from simultaneous extreme-mass-ratio inspirals (SNRs of 10-50), from cosmic-string-cusp bursts (SNRs of 10-100), and from a relatively loud isotropic background with Omega_gw(f) ~ 10^-11, slightly below the LISA instrument noise.Comment: 12 pages, 2 figures, proceedings of the 8th Edoardo Amaldi Conference on Gravitational Waves, New York, June 21-26, 200

Massive Black Hole Binary Inspirals: Results from the LISA Parameter Estimation Taskforce

The LISA Parameter Estimation (LISAPE) Taskforce was formed in September 2007 to provide the LISA Project with vetted codes, source distribution models, and results related to parameter estimation. The Taskforce's goal is to be able to quickly calculate the impact of any mission design changes on LISA's science capabilities, based on reasonable estimates of the distribution of astrophysical sources in the universe. This paper describes our Taskforce's work on massive black-hole binaries (MBHBs). Given present uncertainties in the formation history of MBHBs, we adopt four different population models, based on (i) whether the initial black-hole seeds are small or large, and (ii) whether accretion is efficient or inefficient at spinning up the holes. We compare four largely independent codes for calculating LISA's parameter-estimation capabilities. All codes are based on the Fisher-matrix approximation, but in the past they used somewhat different signal models, source parametrizations and noise curves. We show that once these differences are removed, the four codes give results in extremely close agreement with each other. Using a code that includes both spin precession and higher harmonics in the gravitational-wave signal, we carry out Monte Carlo simulations and determine the number of events that can be detected and accurately localized in our four population models.Comment: 14 pages, 2 figures, 5 tables, minor changes to match version to be published in the proceedings of the 7th LISA Symposium. For more information see the Taskforce's wiki at http://www.tapir.caltech.edu/dokuwiki/lisape:hom

Supplement: "Going the Distance: Mapping Host Galaxies of LIGO and Virgo Sources in Three Dimensions Using Local Cosmography and Targeted Follow-up" (2016, ApJL, 829, L15)

This is a supplement to the Letter of Singer et al., in which we demonstrated a rapid algorithm for obtaining joint 3D estimates of sky location and luminosity distance from observations of binary neutron star mergers with Advanced LIGO and Virgo. We argued that combining the reconstructed volumes with positions and redshifts of possible host galaxies can provide large-aperture but small field of view instruments with a manageable list of targets to search for optical or infrared emission. In this Supplement, we document the new HEALPix-based file format for 3D localizations of gravitational-wave transients. We include Python sample code to show the reader how to perform simple manipulations of the 3D sky maps and extract ranked lists of likely host galaxies. Finally, we include mathematical details of the rapid volume reconstruction algorithm

Covariant Lagrange multiplier constrained higher derivative gravity with scalar projectors

We formulate higher derivative gravity with Lagrange multiplier constraint and scalar projectors. Its gauge-fixed formulation as well as vector fields formulation is developed and corresponding spontaneous Lorentz symmetry breaking is investigated. We show that the only propagating mode is higher derivative graviton while scalar and vector modes do not propagate. Despite to higher derivatives structure of the action, its first FRW equation is the first order differential equation which admits the inflationary universe solution.Comment: Physics Letters B published version. LaTeX 12 page

Crop Updates 2010 - Farming Systems

This session covers twenty papers from different authors: Pests and Disease 1. Preserving phosphine for use in Grain Storage Industry, Christopher R Newman, Department of Agriculture and Food Farming Systems Research 2. Demonstrating the benefits of grazing canola in Western Australia, Jonathan England, Stephen Gherardi and Mohammad Amjad, Department of Agriculture and Food 3. Buloke barley yield when pasture-cropped across subtropical perennial pastures, David Ferris, Department of Agriculture and Food, Phil Ward and Roger Lawes, CSIRO 4. Is pasture cropping viable in WA? Grower perceptions and EverCrop initiatives to evaluate, David Ferris, Tim Wiley, Perry Dolling, Department of Agriculture and Food, Philip Barrett-Lennard, Evergreen farming 5. Best-bet management for dual-purpose canola, John Kirkegaard, Susan Sprague, Hugh Dove and Walter Kelman, CSIRO, Canberra, Peter Hamblin, Agritech Research, Young, NSW 6. Pasture in cropping systems – with and without sheep, Brad Nutt and Angelo Loi, Department of Agriculture and Food 7. Can technology substitute for a lupin break? Wayne Parker, Department of Agriculture and Food 8. Canola row spacing with and without long term stubble retention on a sandy clay loam at Merredin, Glen Riethmuller, Department of Agriculture and Food 9. Impact of stubble retention on water balance and crop yield, Phil Ward1, Ken Flower2,3, Neil Cordingley2 and Shayne Micin1, 1CSIRO, Wembley, Western Australia, 2Western Australian No-Till Farmers Association, 3University of Western Australia Analysis and Modelling 10. Using POAMA rainfall forecasts for crop management in South-West WA, Senthold Asseng1, Peter McIntosh2,3, Mike Pook2,3, James Risbey2,3, Guomin Wang3, Oscar Alves3, Ian Foster4, Imma Farre4 and Nirav Khimashia1, 1CSIRO Plant Industry, Perth, 2CSIRO Marine and Atmospheric Research, Hobart, 3Centre for Australian Weather and Climate Research (CAWCR), A partnership between the Australian Bureau of Meteorology and CSIRO, Melbourne, 4Department of Agriculture and Food 11. Adaption to changing climates and variability – results of the Agribusiness Changing Climates regional workshop, Anderson W3, Beard D3, Blake J3, Grieve R1, Lang M3, Lemon J3, McTaggart R3, Gray D3, Price M2 and Stephens D3, 1Roderick Grieve Farm Management Consultants, 2Coffey International P/L, 3Department of Agriculture and Food 12. Farmers’ management of seasonal variability and climate change in WA, DA Beard, DM Gray, P Carmody, Department of Agriculture and Food 13. Is there a value in having a frost forecast for wheat in South-West WA? Imma Farre1, Senthold Asseng2, Ian Foster1 and Doug Abrecht3, 1Department of Agriculture and Food, CSIRO, Floreat, 2CSIRO Plant Industry, Perth 3Department of Agriculture and Food, Centre for Cropping Systems 14. Does buying rainfall pay? Greg Kirk, Planfarm Agricultural Consultants 15. Which region in the WA wheatbelt makes best use of rainfall? Peter Rowe, Bankwest Agribusiness 16. POAMA – the Predictive Ocean-Atmosphere Model for Australia, Guomin Wang and Oscar Alves, Centre for Australian Weather and Climate Research (CAWCR), A partnership between the Australian Bureau of Meteorology and CSIRO, Melbourne 17. Exploring the link between water use efficiency and farm profitability, Cameron Weeks, Planfarm and Peter Tozer, PRT Consulting Precision Agriculture 18. A plethora of paddock information is available – how does it stack up? Derk Bakker, Department of Agriculture and Food 18. Variable rate prescription mapping for lime inputs based on electromagnetic surveying and deep soil testing, Frank D’Emden, Quenten Knight and Luke Marquis, Precision Agronomics, Australia 19. Trial design and analysis using precision agriculture and farmer’s equipment, Roger Lawes, CSIRO Sustainable Ecosystems, Centre for Environment and Life Sciences, Floreat 20. Farmer perspectives of precision agriculture in Western Australia: Issues and the way forward, Dr Roger Mandel, Curtin Universit