545 research outputs found
Certification as Sabotage: Lessons from Guantanamo Bay
One of President Obama\u27s most public failures was his inability to close the prison at Guantanamo Bay. He had campaigned against the facility throughout the 2008 election, and on his second day in office signed an executive order ordering the base closed within a year. But eight years later the prison remained defiantly open
Studies on the structure and metabolism of polysaccharides
1. Periodate Oxidation of Glycogens. Proceedings of
the Biochemical Society, 17 July 1953. Biochem.J.,
1953, , xx. •
2. Multiple - branching in Arnylopectin. With E.L. Hirst.
Chem. and Ind., 1954, 224. •
3. The Alkali- stability and Molecular Size of Glycogens.
With C.T. Greenwood. Proc. Chem. Soc. , 1957, 26. •
4. Observations on the Absorption Spectra of Polysaccharide -
Iodine Complexes. With A.R. Archibald and A. Wright.
Proceedings of the Biochemical Society, 25 March 1960.
Biochem.J. , 1960, 7,2, in the press. •
5. a -1 :4- Glucosans. Part II. The Molecular Structure
of the Liver Glycogen from a Case of von Gierke's
Disease. J.Chem.Soc., 1954, 3527. •
6. a- 1:4- Glucosans. Part III. The Molecular Structure
of Brewer's Yeast Glycogen. With Khin Maung.
J.Chem.Soc., 1955, 867. •
7. a -1 :4- Glucosans. Part IV. A re- examination of the
Molecular Structure of Floridean Starch. With
I.D. Fleming and E.L. Hirst. J.Chem.Soc., 1936, 2831. •
8. a -1 : 4- Glucosans . Part V. End -group Assay of
Glycogens by Periodate Oxidation, and the Oxidation of
Maltose by Sodium Metaperiodate. With A.R. Archibald.
J.Chem.Soc., 1957, 2205. •
9. a- 1 :4- Glucosans. Part VI. Further Studies on the
Molecular Structures of Glycogens. With A. Margaret
Liddle. J.Chem.Soc., 1957, 3432. •
10. a -1 :4- Glucosans. Part VII. The Enzymic Degradation
and Molecular Structure of Amylase. With J.M.G.
Cowie, I.D. Fleming and C.T. Greenwood. J.Chem.Soc.,
1957, 4430. •
11. a -1 :4- Glucosans. Part VIII. Multiple- branching in
Glycogen and Amylopectin. With A. Margaret Liddle.
J.Chem.Soc., 1957, 4708. •
12. a- 1:4- Glucosans. Part IX. The Molecular Structure
of a Starch -type Polysaccharide from Dunaliella
bioculata. With B.P. Eddy and I.D. Fleming.
J.Chem.Soc., 1958, 2827. •
13. a -1 : 4 -Gluco sans. Part 10. Glycogen Structure and
Rigor Mortis in Mammalian Muscles. With R.A. Lawrie
and A. Wright. Biochem.J., 1959, u, 485. •
14. Physicochemical Studies on Starches. Part XII.
The Molecular Weight of Glycogens in Aqueous Solution.
With W.A.J. Bryce, C.T. Greenwood and I.G. Jones.
J.Chem.Soc., 1958, 711. •
15. Biochemical Investigation of a Case of Glycogen-Storage
Disease (von Gierke's Disease). With A. Calderbank,
P.W. Kent, J. Lorber and A. Wright. Biochem.J.,
1960, 1.4, 223. •
16. Studies on the Metabolism of the Protozoa. Part 6.
The Glycogens of the Parasitic Flagellates
Trichomonas foetus and Trichomonas gallinae.
With J.F. Ryley. Biochem.J., 1955, .53, 369. •
17. Structure of a Reserve Polysaccharide (Leucosin) from
Ochromonas malhamensis. With A.R. Archibald and
J.F. Ryley. Chem. and Ind., 1958, 1516. •
18. Studies on the Metabolism of
The Molecular Structure of a
from Chilomonas paramecium.
E.L. Hirst and J.F. Ryley.
the Protozoa. Part VIII.
Starch -type Polysaccharide
With A.R. Archibald,
J.Chem.Soc., 1960, 556. •
19. A Comparison of IsoLichenin and Lichenin from Iceland
Moss (Cetraria islandica). With N.B. Chanda and
E.L. Hirst. J.Chem.Soc., 1957, 1951. •
20. Periodate Oxidation of Laminarin. With F.B. Anderson
and E.L. Hirst. Chem. and Ind., 1957, 1178. •
21. The Constitution of Laminarin. Part III.
The Fine Structure of Insoluble Laminarin.
With F.B. Anderson, E.L. Hirst and A.G. Ross.
J.Chem.Soc., 1958, 3233. •
22. The Molecular Structure of Glycogens.
Adv. Carbohydrate Chem. , 1957, 12, 261. •
23. Structural Analysis of Polysaccharides. Royal
Institute of Chemistry; Lectures, Monographs and
Reports, 1959, No.2. •
24. The Composition and Structure of Polysaccharides;
Structural Analysis of Polysaccharides by Methylation;
Structural Analysis of Polysaccharides by Periodate
Oxidation. Contributions to the Chemical Section of
the 'Biochemists Handbook' to be published in 1960
by E. and F. Spon Ltd. (Abstract). •
25. Observations on the Carbohydrase Activity of certain
Seaweed Extracts. With W.A.M. Duncan and A.G. Ross.
Proceedings of the Biochemical Society, 9 April 1954.
Biochem.J., 1954, 2, xviii. •
26. Enzyme Systems in Marine Algae. Part 1. The
Carbohydrase Activities of Unfractionated Extracts of
Cladophora rupestris, Laminaria digitata, Rhodrmenia
palmata and Ulva lactuca. With W.A.M. Duncan and
A.G. Ross. Biochem.J., 1956, 6 , 44. •
27. Enzyme Systems in Marine Algae. Part 2. Trans -a-
Glucosylation by Extracts of Cladophora rupestris.
With W.A.M. Duncan. Biochem.J., 1958, §.2, 343. •
28. Enzyme Systems in Marine Algae. Part 3. Trans -ß-
Glucosylation by Extracts of Cladophora rupestres and
Ulva lactuca. With W.A.M. Duncan and J.L. Thompson.
Biochem.J., 1959, ,7 , 295. •
29. The Action of 3- Amylase, Muscle Phosphorylase and Potato
Phosphorylase on some Glycogens. With A. Margaret
Liddle. Proceedings of the Biochemical Society,
16 September 1955. Biochem.J., 1955, 61, xii. •
30. Observations on Barley (3- Glucosidases. Proceedings of the
Biochemical Society, 16 September 1955. Biochem.J.,
1955, 61, xiii. •
31 Observations on the Specificity of Yeast Isoamylase.
With Khin Maung. Chem. and Ind., 1955, 950.
32. Yeast Branching Enzyme. With Khin Maung.
Proceedings of the Biochemical Society, 13 April 1956.
Biochem.J., 1956, L, 16P. •
33. Mechanism of the Degradation of Potato Amylose by
ß- Amylase. With J.M.G. Cowie, I.D. Fleming and
C.T. Greenwood. Chem. and Ind., 1957, 634. •
34. Observations on the Specificity of R- Enzyme.
With I.D. Fleming. Chem. and Ind., 1958, 831. •
35. Enzymic Conversion of Amylopectin into a Glycogen -Type
Polysaccharide. With Zeenat H. Gunja. Chem. and Ind.,
1959, 1017. •
36. Physicochemical Studies on Starches. Part IX. The
Mechanism of the ß- Amylolysis of Amylose and the Nature
of the p -Limit Dextrin. With J.M.G. Cowie, I.D.
Fleming and C.T. Greenwood. J.Chem.Soc., 1958, 697. •
37. Studies on Carbohydrate -Metabolizing Enzymes. Part 1.
Trans -ß- Glucosylation by Barley Enzymes.
With F.B. Anderson. Biochem.J., 1959, 71, 407. •
38. Studies on Carbohydrate -Metabolizing Enzymes. Part 2.
Trans -a- Glucosylation by Extracts of Tetrahymena
pyriformis. With A.R. Archibald. Biochem.J., 1959, 7, 292. •
39. Studies on Carbohydrate -Metabolizing Enzymes. Part 3.
Yeast Branching Enzyme. With Z.H. Gunja and Khin
Maung. Biochem.J., 1960, 75, 441. (page proof) . •
40. Studies on Carbohydrate -Metabolizing Enzymes. Part 4.
The Action of Z- Enzyme on Starch -type Polysaccharides.
With W.L. Cunningham, A. Wright and I.D. Fleming.
J.Chem.Soc., 1960, in the press. (Accepted February 1960). •
41. The Enzymic Degradation of Starch and Glycogen.
Ann.Re orts, Chem.Soc., 1954, Q, 288. •
42. The Enzymic Degradation of Polysaccharides.
Quart. Revs. , 1955, 2, 73 •
43. The Properties of P- Enzyme, Glycogen Phosphorylase,
Q- Enzyme and Branching Enzyme. Contributions to the
Enzymological Section of the 'Biochemists Handbook' to
be published in 1960 by E. and F. Spon Ltd. •
44 Trans a- and ß- Glucosylation Reactions. Bull.Soc.Chim.
Biol., 1960, in the press. (Submitted February 1960)
Versatile and controlled functionalization of polyferrocenylsilane-<i>b</i>-polyvinylsiloxane block copolymers using a <i>N</i>-hydroxysuccinimidyl ester strategy
Results from a set of three-dimensional numerical experiments of a hot Jupiter atmosphere
We present highlights from a large set of simulations of a hot Jupiter
atmosphere, nominally based on HD 209458b, aimed at exploring both the
evolution of the deep atmosphere, and the acceleration of the zonal flow or
jet. We find the occurrence of a super-rotating equatorial jet is robust to
changes in various parameters, and over long timescales, even in the absence of
strong inner or bottom boundary drag. This jet is diminished in one simulation
only, where we strongly force the deep atmosphere equator-to-pole temperature
gradient over long timescales. Finally, although the eddy momentum fluxes in
our atmosphere show similarities with the proposed mechanism for accelerating
jets on tidally-locked planets, the picture appears more complex. We present
tentative evidence for a jet driven by a combination of eddy momentum transport
and mean flow.Comment: 26 pages, 22 Figures. Accepted for publication in Astronomy and
Astrophysic
Accuracy tests of radiation schemes used in hot Jupiter global circulation models
The treatment of radiation transport in global circulation models (GCMs) is crucial to correctly describe Earth and exoplanet atmospheric dynamics processes. The two-stream approximation and correlated-k method are currently state-of-the-art approximations applied in both Earth and hot Jupiter GCM radiation schemes to facilitate rapid calculation of fluxes and heating rates. Their accuracy have been tested extensively for Earth-like conditions, but verification of the methods' applicability to hot Jupiter-like conditions is lacking in the literature. We are adapting the UK Met Office GCM, the Unified Model (UM), for the study of hot Jupiters, and present in this work the adaptation of the Edwards-Slingo radiation scheme based on the two-stream approximation and the correlated-k method. We discuss the calculation of absorption coefficients from high temperature line lists and highlight the large uncertainty in the pressure-broadened line widths. We compare fluxes and heating rates obtained with our adapted scheme to more accurate discrete ordinate (DO) line-by-line (LbL) calculations ignoring scattering effects. We find that, in most cases, errors stay below 10 % for both heating rates and fluxes using ~ 10 k-coefficients in each band and a diffusivity factor D = 1.66. The two-stream approximation and the correlated-k method both contribute non-negligibly to the total error. We also find that using band-averaged absorption coefficients, which have previously been used in radiative-hydrodynamical simulations of a hot Jupiter, may yield errors of ~ 100 %, and should thus be used with caution.European Community’s Seventh Framework Programme FP7/2007-2013Science & Technology Facilities Council (STFC)Royal Societ
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Homo- and heterodehydrocoupling of phosphines mediated by alkali metal catalysts
Catalytic chemistry that involves the activation and transformation of main group substrates is relatively undeveloped and current examples are generally mediated by expensive transition metal species. Herein, we describe the use of inexpensive and readily available tBuOK as a catalyst for P–P and P–E (E = O, S, or N) bond formation. Catalytic quantities of tBuOK in the presence of imine, azobenzene hydrogen acceptors, or a stoichiometric amount of tBuOK with hydrazobenzene, allow efficient homodehydrocoupling of phosphines under mild conditions (e.g. 25 °C and < 5 min). Further studies demonstrate that the hydrogen acceptors play an intimate mechanistic role. We also show that our tBuOK catalysed methodology is general for the heterodehydrocoupling of phosphines with alcohols, thiols and amines to generate a range of potentially useful products containing P–O, P–S, or P–N bonds
Studies on β-glucanases. Some properties of a bacterial endo-β-(1→3)-glucanase system
Observable signatures of wind-driven chemistry with a fully consistent three dimensional radiative hydrodynamics model of HD 209458b (dataset)
rt_u-as329 - tracer experimentrt_u-as361 - transmission - equilibriumrt_u-as298 - transmission -relaxationrt_u-ar698 - emission - equilibriumrt_u-ar697 - emission - relaxationrt_u-ar586 - relaxationrt_u-ar412 - equilibriumtf_u-ar475 - start from spun up windstf_u-ar354 - resolution 96X60X33 start from spun up windstf_u-ar333 - resolution 72X45X33 start from spun up windstf_u-aq931 - timescale x 1e-8tf_u-aq930 - timescale x 1e-4tf_u-aq815 - resolution 72X45X33tf_u-aq814 - resolution 96X60X33tf-u-aq801 - chemical equilibriumtf_u-aq557 - standard Cooper and Showman 2006tf_u-aq800 - Initialise all carbon in COThe data contained in this submission is associated with the publication Drummond et al, ApJL, 2018.The article associated with this dataset is located in ORE at: http://hdl.handle.net/10871/31897We present a study of the effect of wind-driven advection on the chemical composition of hot Jupiter atmospheres using a fully-consistent 3D hydrodynamics, chemistry and radiative transfer code, the Met Office Unified Model (UM). Chemical modelling of exoplanet atmospheres has primarily been restricted to 1D models that cannot account for 3D dynamical processes. In this work we couple a chemical relaxation scheme to the UM to account for the chemical interconversion of methane and carbon monoxide. This is done consistently with the radiative transfer meaning that departures from chemical equilibrium are included in the heating rates (and emission) and hence complete the feedback between the dynamics, thermal structure and chemical composition. In this letter we simulate the well studied atmosphere of HD 209458b. We find that the combined effect of horizontal and vertical advection leads to an increase in the methane abundance by several orders of magnitude; directly opposite to the trend found in previous works. Our results demonstrate the need to include 3D effects when considering the chemistry of hot Jupiter atmospheres. We calculate transmission and emission spectra, as well as the emission phase curve, from our simulations. We conclude that gas-phase non-equilibrium chemistry is unlikely to explain the model–observation discrepancy in the 4.5 μm Spitzer/IRAC channel. However, we highlight other spectral regions, observable with the James Webb Space Telescope, where signatures of wind-driven chemistry are more prominant.BD and DKS acknowledge funding from the European Research Council (ERC) under the European Unions Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement no. 336792. NJM is part funded by a Leverhulme Trust Research Project Grant. JM and IAB acknowledge the support of a Met Office Academic Partnership secondment. ALC is funded by an STFC studentship. DSA acknowledges support from the NASA Astrobiology Program through the Nexus for Exoplanet System Science. This work used the DiRAC Complexity system, operated by the University of Leicester IT Services, which forms part of the STFC DiRAC HPC Facility. This equipment is funded by BIS National E-Infrastructure capital grant ST/K000373/1 and STFC DiRAC Operations grant ST/K0003259/1. DiRAC is part of the National E-Infrastructure
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The impact of two coupled cirrus microphysics-radiation parameterizations on the temperature and specific humidity biases in the tropical tropopause layer in a climate model
The impact of two different coupled cirrus microphysics-radiation parameterizations on the zonally averaged temperature and humidity biases in the tropical tropopause layer (TTL) of a Met Office climate model configuration is assessed. One parameterization is based on a linear coupling between a model prognostic variable, the ice mass mixing ratio, qi, and the integral optical properties. The second is based on the integral optical properties being parameterized as functions of qi and temperature, Tc, where the mass coefficients (i.e. scattering and extinction) are parameterized as nonlinear functions of the ratio between qi and Tc. The cirrus microphysics parameterization is based on a moment estimation parameterization of the particle size distribution (PSD), which relates the mass moment (i.e. second moment if mass is proportional to size raised to the power of 2 ) of the PSD to all other PSD moments through the magnitude of the second moment and Tc. This same microphysics PSD parameterization is applied to calculate the integral optical properties used in both radiation parameterizations and, thus, ensures PSD and mass consistency between the cirrus microphysics and radiation schemes. In this paper, the temperature-non-dependent and temperature-dependent parameterizations are shown to increase and decrease the zonally averaged temperature biases in the TTL by about 1 K, respectively. The temperature-dependent radiation parameterization is further demonstrated to have a positive impact on the specific humidity biases in the TTL, as well as decreasing the shortwave and longwave biases in the cloudy radiative effect. The temperature-dependent radiation parameterization is shown to be more consistent with TTL and global radiation observations
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