Kinetics of Dark Oxygen Uptake of Pocillopora damicornis

Colonies of Pocillopora damicornis were placed in a sealed aquarium in the dark. Water velocity was altered and measured in 10 different experiments. During each experiment, seawater in the aquarium was supersaturated with oxygen (02 ) and then O2 concentration was measured through time until the concentration in the aquarium decreased to 0.3 mg O2 1-1 . Resulting O2 uptake curves were interpreted as a function of water velocity. Rate of O2 uptake fit a hyperbolic equation (d02 /dt = Vm02 /Ks + O2 ) . Maximum uptake rate (Vm ) varied between 0.12 and 0.27 mg O2 1- 1 min " (mean = 0. 18), and the half-saturation constant (Ks ) varied between 0.86 and 2.52 mg O2 1-1. Both Vm and K, did not vary with water velocity, indicating that in these experiments, water motion had little influence on either diffusive boundary layers near the coral tissue or the metabolic rate of O2 uptake. Even supersaturated concentrations of O2 did not completely saturate the uptake capacity of this enzyme system

Scandium triflate catalyzed ester synthesis using primary amides

AbstractA scandium triflate (ScOTf)3 catalyzed methodology has been developed to synthesize esters from primary amides. Various primary and secondary aliphatic alcohols have been shown to react in n-heptane with a range of primary amides for 24h

Modelling the future of the Hawaiian honeycreeper : an ecological and epidemiological problem

The Hawaiian honeycreeper (Drepanididae) faces the threat of extinction; this is believed to be due primarily to predation from alien animals, endemic avian malaria (Plasmodium relictum) and climate change. A deterministic SI modelling approach is developed, incorporating these three factors and a metapopulation approach in conjunction with a quasi-equilibrium assumption to simplify the vector populations. This enables the qualitative study of the behaviour of the system. Numerical results suggest that although (partial) resistance to avian malaria may be advantageous for individual birds, allowing them to survive infection, this allows them to become carriers of infection and hence greatly increases the spread of this disease. Predation obviously reduces the life-expectancy of honeycreepers, but in turn this reduces the spread of infection from resistant carriers; therefore the population-level impact of predation is reduced. Various control strategies proposed in the literature are also considered and it is shown that predation control could either help or hinter, depending upon resistance of the honeycreeper species. Captive propagation or habitat restoration may be the best feasible solution to the loss of both heterogeneity within the population and the loss of the species as a whole

Sponges and ascidians control removal of particulate organic nitrogen from coral reef water

10 pages, 5 figures, 5 tables.-- This is HIMB contribution 1199 and SOEST contribution 6596We studied removal rates of plankton and total particulate organic nitrogen (PON) by benthic reef communities from the overlying water in a large experimental flume. The flume was filled with mixtures of coral and coral rubble, and biomass of plankton was measured as water was recirculated over the experimental benthic community. All planktonic particle types, picoplankton, nanoplankton, microplankton, and total PON, decreased in concentration at rates proportional to their biomass. The mean first-order rate constant for the decrease in particle concentration was 96 ± 61 × 10-6 m s-1, corresponding to PON uptake of 10 mmol N m-2 d -1. Synechococcus sp. and heterotrophic bacteria were the major sources of PON. Particulate organic nitrogen removed by rubble and live coral assemblages was directly related to sponge and ascidian biomass (number and area) on the coral and coral rubble. Uptake of PON was about the same as the previously measured uptake of dissolved inorganic nitrogen into these coral reef communities, making it an important flux of nitrogen into the reef. © 2005, by the American Society of Limnology and Oceanography, Inc.Support for this work was provided by a postdoctoral fellowship from the Ministerio de Educación y Cultura (MEC) and a Ramón y Cajal research contract to M.R. This paper was funded in part by NOAA project R/CR-1, which is sponsored by the University of Hawaii Sea Grant College Program, School of Ocean and Earth Science Technology (SOEST), under grant NA 86RG0041. Additional funding was provided by CISNet (NOAA project NA 870A0531) and TransCom (Transfer at Community level) project (REN2002-01631/MAR)Peer Reviewe

FIRI - a Far-Infrared Interferometer

Half of the energy ever emitted by stars and accreting objects comes to us in the FIR waveband and has yet to be properly explored. We propose a powerful Far-InfraRed Interferometer mission, FIRI, to carry out high-resolution imaging spectroscopy in the FIR. This key observational capability is essential to reveal how gas and dust evolve into stars and planets, how the first luminous objects in the Universe ignited, how galaxies formed, and when super-massive black holes grew. FIRI will disentangle the cosmic histories of star formation and accretion onto black holes and will trace the assembly and evolution of quiescent galaxies like our Milky Way. Perhaps most importantly, FIRI will observe all stages of planetary system formation and recognise Earth-like planets that may harbour life, via its ability to image the dust structures in planetary systems. It will thus address directly questions fundamental to our understanding of how the Universe has developed and evolved - the very questions posed by ESA's Cosmic Vision.Comment: Proposal developed by a large team of astronomers from Europe, USA and Canada and submitted to the European Space Agency as part of "Cosmic Vision 2015-2025

Effect of Interband Transitions on the c axis Penetration Depth of Layered Superconductors

The electromagnetic response of a system with two planes per unit cell involves, in addition to the usual intraband contribution, an added interband term. These transitions affect the temperature dependence and the magnitude of the zero temperature c-axis penetration depth. When the interplane hopping is sufficiently small, the interband transitions dominate the low temperature behaviour of the penetration depth which then does not reflect the linear temperature dependence of the intraband term and in comparison becomes quite flat even for a d-wave gap. It is in this regime that the pseudogap was found in our previous normal state calculations of the c-axis conductivity, and the effects are connected.Comment: 8 pages, 5 figure

ATLAS Tracking Event Data Model

In this report the event data model (EDM) relevant for tracking in the ATLAS experiment is presented. The core component of the tracking EDM is a common track object which is suited to describe tracks in the innermost tracking sub-detectors and in the muon detectors in offline as well as online reconstruction. The design of the EDM was driven by a demand for modularity and extensibility while taking into account the different requirements of the clients. The structure of the track object and the representation of the tracking-relevant information are described in detail

PET/MRI attenuation estimation in the lung: A review of past, present, and potential techniques

Positron emission tomography/magnetic resonance imaging (PET/MRI) potentially offers several advantages over positron emission tomography/computed tomography (PET/CT), for example, no CT radiation dose and soft tissue images from MR acquired at the same time as the PET. However, obtaining accurate linear attenuation correction (LAC) factors for the lung remains difficult in PET/MRI. LACs depend on electron density and in the lung, these vary significantly both within an individual and from person to person. Current commercial practice is to use a single-valued population-based lung LAC, and better estimation is needed to improve quantification. Given the under-appreciation of lung attenuation estimation as an issue, the inaccuracy of PET quantification due to the use of single-valued lung LACs, the unique challenges of lung estimation, and the emerging status of PET/MRI scanners in lung disease, a review is timely. This paper highlights past and present methods, categorizing them into segmentation, atlas/mapping, and emission-based schemes. Potential strategies for future developments are also presented

Nonlinear stability of oscillatory wave fronts in chains of coupled oscillators

We present a stability theory for kink propagation in chains of coupled oscillators and a new algorithm for the numerical study of kink dynamics. The numerical solutions are computed using an equivalent integral equation instead of a system of differential equations. This avoids uncertainty about the impact of artificial boundary conditions and discretization in time. Stability results also follow from the integral version. Stable kinks have a monotone leading edge and move with a velocity larger than a critical value which depends on the damping strength.Comment: 11 figure