2,753 research outputs found
RGS9-1 is required for normal inactivation of mouse cone phototransduction
Purpose: To test the hypothesis that Regulator of G-protein Signaling 9 (RGS9-1) is necessary for the normal inactivation of retinal cones.
Methods: Mice having the gene RGS9-1 inactivated in both alleles (RGS9-1 -/-) were tested between the ages 8-10 weeks
with electroretinographic (ERG) protocols that isolate cone-driven responses. Immunohistochemistry was performed with a primary antibody against RGS9-1 (anti-RGS9-1c), with the secondary conjugated to fluorescein isothiocyanate, and
with rhodamine-conjugated peanut agglutinin.
Results: (1) Immunohistochemistry showed RGS9-1 to be strongly expressed in the cones of wildtype (WT is C57BL/6)
mice, but absent from the cones of RGS9-1 mice. (2) Cone-driven b-wave responses of dark-adapted RGS9-1 -/- mice had saturating amplitudes and sensitivities in the midwave and UV regions of the spectrum equal to or slightly greater than those of WT (C57BL/6) mice. (3) Cone-driven b-wave and a-wave responses of RGS9-1 -/- mice recovered much more slowly than those of WT after a strong conditioning flash: for a flash estimated to isomerize 1.2% of the M-cone pigment and 0.9% of the UV-cone pigment, recovery of 50% saturating amplitude was approximately 60-fold slower than in WT.
Conclusions: (1) The amplitudes and sensitivities of the cone-driven responses indicate that cones and cone-driven neurons in RGS9-1 -/- mice have normal generator currents. (2) The greatly retarded recovery of cone-driven responses of RGS9-1 -/- mice relative to those of WT mice establishes that RGS9-1 is required for normal inactivation of the cone
phototransduction cascades of both UV- and M-cones
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Serving GODAE Data and Products to the Ocean Community
The Global Ocean Data Assimilation Experiment (GODAE [http://
www.godae.org]) has spanned a decade of rapid technological development. The ever-increasing volume and diversity of oceanographic data produced by in situ instruments, remote-sensing platforms, and computer simulations have driven
the development of a number of innovative technologies that are essential for connecting scientists with the data that they need. This paper gives an overview of the technologies that have been developed and applied in the course of GODAE, which now provide users of oceanographic data with the capability to discover, evaluate, visualize, download, and analyze data from all over the world. The key to this
capability is the ability to reduce the inherent complexity of oceanographic data by providing a consistent, harmonized view of the various data products. The challenges of data serving have been addressed over the last 10 years through the cooperative skills and energies of many individuals
Global consequences of afforestation and bioenergy cultivation on ecosystem service indicators
Land management for carbon storage is discussed as being indispensable for climate change mitigation because of its large potential to remove carbon dioxide from the atmosphere, and to avoid further emissions from deforestation. However, the acceptance and feasibility of land-based mitigation projects depends on potential side effects on other important ecosystem functions and their services. Here, we use projections of future land use and land cover for different land-based mitigation options from two land-use models (IMAGE and MAgPIE) and evaluate their effects with a global dynamic vegetation model (LPJ-GUESS). In the land-use models, carbon removal was achieved either via growth of bioenergy crops combined with carbon capture and storage, via avoided deforestation and afforestation, or via a combination of both. We compare these scenarios to a reference scenario without land-based mitigation and analyse the LPJ-GUESS simulations with the aim of assessing synergies and trade-offs across a range of ecosystem service indicators: carbon storage, surface albedo, evapotranspiration, water runoff, crop production, nitrogen loss, and emissions of biogenic volatile organic compounds.
In our mitigation simulations cumulative carbon storage by year 2099 ranged between 55 and 89âŻGtC. Other ecosystem service indicators were influenced heterogeneously both positively and negatively, with large variability across regions and land-use scenarios. Avoided deforestation and afforestation led to an increase in evapotranspiration and enhanced emissions of biogenic volatile organic compounds, and to a decrease in albedo, runoff, and nitrogen loss. Crop production could also decrease in the afforestation scenarios as a result of reduced crop area, especially for MAgPIE land-use patterns, if assumed increases in crop yields cannot be realized. Bioenergy-based climate change mitigation was projected to affect less area globally than in the forest expansion scenarios, and resulted in less pronounced changes in most ecosystem service indicators than forest-based mitigation, but included a possible decrease in nitrogen loss, crop production, and biogenic volatile organic compounds emissions
Effect of the cation structure on the properties of homobaric imidazolium ionic liquids
In this work we investigate the structureâproperty relationships in a series of alkylimidazolium ionic liquids with almost identical molecular weight. Using a combination of theoretical calculations and experimental measurements, we have shown that re-arranging the alkyl side chain or adding functional groups results in quite distinct features in the resultant ILs. The synthesised ILs, although structurally very similar, cover a wide spectrum of properties ranging from highly fluid, glass forming liquids to high melting point crystalline salts. Theoretical ab initio calculations provide insight on minimum energy orientations for the cations, which then are compared to experimental X-ray crystallography measurements to extract information on hydrogen bonding and to verify our understanding of the studied structures. Molecular dynamics simulations of the simplest (core) ionic liquids are used in order to help us interpret our experimental results and understand better why methylation of C2 position of the imidazolium ring results in ILs with such different properties compared to their non-methylated analogues
Instanton classical solutions of SU(3) fixed point actions on open lattices
We construct instanton-like classical solutions of the fixed point action of
a suitable renormalization group transformation for the SU(3) lattice gauge
theory. The problem of the non-existence of one-instantons on a lattice with
periodic boundary conditions is circumvented by working on open lattices. We
consider instanton solutions for values of the size (0.6-1.9 in lattice units)
which are relevant when studying the SU(3) topology on coarse lattices using
fixed point actions. We show how these instanton configurations on open
lattices can be taken into account when determining a few-couplings
parametrization of the fixed point action.Comment: 23 pages, LaTeX, 4 eps figures, epsfig.sty; some comments adde
Locality and topology with fat link overlap actions
We study the locality and topological properties of fat link clover overlap
(FCO) actions. We find that a small amount of fattening (2-4 steps of APE or 1
step of HYP) already results in greatly improved properties compared to the
Wilson overlap (WO). We present a detailed study of the localisation of the FCO
and its connection to the density of low modes of . In contrast to
the Wilson overlap, on quenched gauge backgrounds we do not find any dependence
of the localization of the FCO on the gauge coupling. This suggests that the
FCO remains local in the continuum limit. The FCO also faithfully reproduces
the zero mode wave functions of typical lattice instantons, not like the Wilson
overlap. After a general discussion of different lattice definitions of the
topological charge we also show that the FCO together with the Boulder charge
are likely to satisfy the index theorem in the continuum limit. Finally, we
present a high statistics computation of the quenched topological
susceptibility with the FCO action.Comment: 19 pages, LaTe
High-pressure structural, elastic and electronic properties of the scintillator host material, KMgF_3
The high-pressure structural behaviour of the fluoroperovskite KMgF_3 is
investigated by theory and experiment. Density functional calculations were
performed within the local density approximation and the generalized gradient
approximation for exchange and correlation effects, as implemented within the
full-potential linear muffin-tin orbital method. In situ high-pressure powder
x-ray diffraction experiments were performed up to a maximum pressure of 40 GPa
using synchrotron radiation. We find that the cubic Pm\bar{3}m crystal symmetry
persists throughout the pressure range studied. The calculated ground state
properties -- the equilibrium lattice constant, bulk modulus and elastic
constants -- are in good agreement with experimental results. By analyzing the
ratio between the bulk and shear modulii, we conclude that KMgF_3 is brittle in
nature. Under ambient conditions, KMgF_3 is found to be an indirect gap
insulator with the gap increasing under pressure.Comment: 4 figure
Effect of vessel wettability on the foamability of "ideal" surfactants and "real-world" beer heads
The ability to tailor the foaming properties of a solution by controlling its chemical composition is highly desirable and has been the subject of extensive research driven by a range of applications. However, the control of foams by varying the wettability of the foaming vessel has been less widely reported. This work investigates the effect of the wettability of the side walls of vessels used for the in situ generation of foam by shaking aqueous solutions of three different types of model surfactant systems (non-ionic, anionic and cationic surfactants) along with four different beers (Guinness Original, Banksâs Bitter, Bass No 1 and Harvest Pale). We found that hydrophilic vials increased the foamability only for the three model systems but increased foam stability for all foams except the model cationic system. We then compared stability of beer foams produced by shaking and pouring and demonstrated weak qualitative agreement between both foam methods. We also showed how wettability of the glass controls bubble nucleation for beers and champagne and used this effect to control exactly where bubbles form using simple wettability patterns
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Auxiliary feedwater system risk-based inspection guide for the J. M. Farley Nuclear Power Plant
In a study sponsored by the US Nuclear Regulatory Commission (NRC), Pacific Northwest Laboratory has developed and applied a methodology for deriving plant-specific risk-based inspection guidance for the auxiliary feedwater (AFW) system at pressurized water reactors that have not undergone probabilistic risk assessment(PRA). This methodology uses existing PRA results and plant operating experience information. Existing PRA-based inspection guidance recently developed for the NRC for various plants was used to identify generic component failure modes. This information was then combined with plant-specific and industry-wide component information and failure data to identify failure modes and failure mechanisms for the AFW system at the selected plants. J. M. Farley was selected as the second plant for study. The product of this effort is a prioritized listing of AFW failures which have occurred at the plant and at other PWRs. This listing is intended for use by NRC inspectors in the preparation of inspection plans addressing AFW risk-important at the J. M. Farley plant. 23 refs., 1 fig., 1 tab
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