904 resultados para Formation of the historian
Resumo:
The impact and content of English as a subject on the curriculum is once more the subject of lively debate. Questions of English sets out to map the development of English as a subject and how it has come to encompass the diversity of ideas that currently characterise it. Drawing on a combination of historical analysis and recent research findings Robin Peel, Annette Patterson and Jeanne Gerlach bring together and compare important new insights on curriculum development and teaching practice from England, Australia and the United States. They also discuss the development of teacher training, highlighting the variety of ways in which teachers build their own beliefs and knowledge about English.
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The anionic heterocumulene SCCCN- was generated in the gas phase by collisional activation of the radical anion of 1,2-dicyanoethylenedithiolate. The mechanism of this reaction, as well as the structures of neutral and anionic products, was investigated by hybrid density functional theory (DFT) calculations. Dissociation to form SCCCN- and SCN is proposed to occur by a radical directed cyano migration reaction, with calculations suggesting this is the lowest energy fragmentation pathway available to the precursor anion. In contrast, the even-electron protonated 1,2-dicyanoethylenedithiolate anion fragmented by loss of HCN.
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We present a determination of Delta(f)H(298)(HOO) based upon a negative. ion thermodynamic cycle. The photoelectron spectra of HOO- and DOO- were used to measure the molecular electron affinities (EAs). In a separate experiment, a tandem flowing afterglow-selected ion flow tube (FA-SIFT) was used to measure the forward and reverse rate constants for HOO- + HCdropCH reversible arrow HOOH + HCdropC(-) at 298 K, which gave a value for Delta(acid)H(298)(HOO-H). The experiments yield the following values: EA(HOO) = 1.078 +/- 0.006 eV; T-0((X) over tilde HOO - (A) over tilde HOO) = 0.872 +/- 0.007 eV; EA(DOO) = 1.077 +/- 0.005 eV; T-0((X) over tilde DOO - (A) over tilde DOO) = 0.874 +/- 0.007 eV; Delta(acid)G(298)(HOO-H) = 369.5 +/- 0.4 kcal mol(-1); and Delta(acid)H(298)(HOO-H) = 376.5 +/- 0.4 kcal mol(-1). The acidity/EA thermochemical cycle yields values for the bond enthalpies of DH298(HOO-H) = 87.8 +/- 0.5 kcal mol(-1) and Do(HOO-H) = 86.6 +/- 0.5 kcal mol(-1). We recommend the following values for the heats of formation of the hydroperoxyl radical: Delta(f)H(298)(HOO) = 3.2 +/- 0.5 kcal mol(-1) and Delta(f)H(0)(HOO) = 3.9 +/- 0.5 kcal mol(-1); we recommend that these values supersede those listed in the current NIST-JANAF thermochemical tables.
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Red blood cells (RBCs) are nonnucleated liquid capsules, enclosed in deformable viscoelastic membranes with complex three dimensional geometrical structures. Generally, RBC membranes are highly incompressible and resistant to areal changes. However, RBC membranes show a planar shear deformation and out of plane bending deformation. The behaviour of RBCs in blood vessels is investigated using numerical models. All the characteristics of RBC membranes should be addressed to develop a more accurate and stable model. This article presents an effective methodology to model the three dimensional geometry of the RBC membrane with the aid of commercial software COMSOL Multiphysics 4.2a and Fortran programming. Initially, a mesh is generated for a sphere using the COMSOL Multiphysics software to represent the RBC membrane. The elastic energy of the membrane is considered to determine a stable membrane shape. Then, the actual biconcave shape of the membrane is obtained based on the principle of virtual work, when the total energy is minimised. The geometry of the RBC membrane could be used with meshfree particle methods to simulate motion and deformation of RBCs in micro-capillaries
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The coat protein gene of physalis mottle tymovirus (PhMV) was over expressed in Escherichia coli using pET-3d vector. The recombinant protein was found to self assemble into capsids in vivo. The purified recombinant capsids had an apparent s value of 56.5 S and a diameter of 29(±2) nm. In order to establish the role of amino and carboxy-terminal regions in capsid assembly, two amino-terminal deletions clones lacking the first 11 and 26 amino acid residues and two carboxy-terminal deletions lacking the last five and ten amino acid residues were constructed and overexpressed. The proteins lacking N-terminal 11 (PhCPN1) and 26 (PhCPN2) amino acid residues self assembled into T = 3 capsids in vivo, as evident from electron microscopy, ultracentrifugation and agarose gel electrophoresis. The recombinant, PhCPN1 and PhCPN2 capsids were as stable as the empty capsids formed in vivo and encapsidated a small amount of mRNA. The monoclonal antibody PA3B2, which recognizes the epitope within region 22 to 36, failed to react with PhCPN2 capsids while it recognized the recombinant and PhCPN1 capsids. Disassembly of the capsids upon treatment with urea showed that PhCPN2 capsids were most stable. These results demonstrate that the N-terminal 26 amino acid residues are not essential for T = 3 capsid assembly in PhMV. In contrast, both the proteins lacking the C-terminal five and ten amino acid residues were present only in the insoluble fraction and could not assemble into capsids, suggesting that these residues are crucial for folding and assembly of the particles.
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An Ocean General Circulation Model of the Indian Ocean with high horizontal (0.25 degrees x 0.25 degrees) and vertical (40 levels) resolutions is used to study the dynamics and thermodynamics of the Arabian Sea mini warm pool (ASMWP), the warmest region in the northern Indian Ocean during January-April. The model simulates the seasonal cycle of temperature, salinity and currents as well as the winter time temperature inversions in the southeastern Arabian Sea (SEAS) quite realistically with climatological forcing. An experiment which maintained uniform salinity of 35 psu over the entire model domain reproduces the ASMWP similar to the control run with realistic salinity and this is contrary to the existing theories that stratification caused by the intrusion of low-salinity water from the Bay of Bengal into the SEAS is crucial for the formation of ASMWP. The contribution from temperature inversions to the warming of the SEAS is found to be negligible. Experiments with modified atmospheric forcing over the SEAS show that the low latent heat loss over the SEAS compared to the surroundings, resulting from the low winds due to the orographic effect of Western Ghats, plays an important role in setting up the sea surface temperature (SST) distribution over the SEAS during November March. During March-May, the SEAS responds quickly to the air-sea fluxes and the peak SST during April-May is independent of the SST evolution during previous months. The SEAS behaves as a low wind, heat-dominated regime during November-May and, therefore, the formation and maintenance of the ASMWP is not dependent on the near surface stratification.
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Ceric ammonium sulfate, CAS, oxidizes naphthalene to 1,4-naphthoquinone in essentially quantitative yield in CH3CN-dil. H2SO4. Stoichiometric studies indicate that 6 mol of CAS are required for the oxidation of 1 mol of naphthalene to 1,4-naphthoquinone. Kinetic investigations reveal that the reaction takes place through initial formation of a 1:1 complex of naphthalene and cerium(IV) in an equilibrium step followed by slow decomposition of the complex to naphthalene radical cation. Kinetic results on the effects of acid strength, polarity of the medium, temperature and substituents are in accordance with this mechanism. Further conversion of the radical cation into 1,4-naphthoquinone takes place in fast steps involving a further 5 mol of cerium(IV) and 2 mol of H2O.
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Reduction behaviour of Fe3+/Al2O3 obtained by the decomposition of the oxalate precursor has been investigated by employing X-ray diffraction (XRD), Mössbauer spectroscopy and electron paramagnetic resonance (EPR) spectroscopy. Calcination of Fe3+/Al2O3 at or below 1070 K yields mainly a poorly ordered, fine particulate form of ?-Al2�xFexO3. Calcination at or above 1220 K yields ?-Al2�xFexO3. Reduction of Fe3+/Al2O3 samples calcined at or below 1070 K gives the FeAl2O4 spinel on reduction at 870 K; samples calcined at or above 1220 K give Al2-xFexO3 with a very small proportion of metallic iron. Fe3+/Al2O3 samples calcined at 1220 K or above yield metallic iron and a very small proportion of the spinel on reduction below 1270 K. In the samples reduced at or above 1270 K, the main product is metallic iron in both ferromagnetic and superparamagnetic forms. The oxalate precursor route yields more metallic iron than the sol�gel route.
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Phase relations in the pseudoternary system CaO-CoO-SiO2 have been established at 1323 K. Three quaternary oxides were found to be stable: CaCoSi2O6 with clinopyroxene (Cpx), Ca2CoSi2O7 with melilite (Mel), and CaCoSiO4 with olivine (Ol) structures. The Gibbs energies of formation of the quaternary oxides from their component binary oxides were measured using solid-state galvanic cells incorporating yttria-stabilized zirconia as the solid electrolyte in the temperature range of 1000-1324 K. The results can be summarized as follows: CoO (rs) + CaO (rs) + 2SiO(2) (Qtz) --> CaCoSi2O6 (Cpx), Delta G(f)(0) = -117920 + 11.26T (+/-150) J/mol CoO (rs) + 2CaO (rs) + 2SiO(2) (Qtz) --> Ca2CoSi2O7 (Mel), Delta G(f)(0) = -192690 + 2.38T (+/-130) J/mol CoO (rs) + CaO (rs) + SiO2 (Qtz) --> CaCoSiO2 (Ol), Delta G(f)(0) = -100325 + 2.55T (+/-100) J/mol where rs = rock salt (NaCl) structure and Qtz = quartz. The uncertainty limits correspond to twice the standard error estimate. The experimentally observed miscibility gaps along the joins CaO-CoO and CaCoSiO4-Co2SiO4 were used to calculate the excess free energies of mixing for the solid solutions CaxCo1-xO and (CayCo1-y)CoSiO4:Delta G(E) = X(1 - X)[31975X + 26736 (1 - X)] J/mol and Delta G(E) = 23100 (+/-250) Y(1 - Y) J/mol. A T-X phase diagram for the binary CaO-CoO was computed from the thermodynamic information; the diagram agrees with information available in the literature. The computed miscibility gap along the CaCoSiO4-Co2SiO4 join is associated with a critical temperature of 1389 (+/-15) K. Stability fields for the various solid solutions and the quaternary compounds are depicted on chemical-potential diagrams for SiO2, CaO, and CoO at 1323 K.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): The U.S. Geological Survey is working to define a hydroclimatic data network. The Geological Survey collects stream discharge data at more than 7000 sites throughout the United States. Many of these stations are operated to supply information about specific activities such as flood control, irrigation projects, or hydropower generation. As a beginning, the Geological Survey will attempt to identify stations that represent natural streamflow. Several lists of stations representing "natural" streamflow have been complied in the past. While there is some overlap among these lists, a consistent compilation is preferred. The present effort is to produce one list identifying those stations having periods of record which would be suitable for mesoscale climatic analyses.
Resumo:
Ure2p is the protein determinant of the Saccharomyces cerevisiae prion state [URE3]. Constitutive overexpression of the HSP70 family member SSA1 cures cells of [URE3]. Here, we show that Ssa1p increases the lag time of Ure2p fibril formation in vitro in the presence or absence of nucleotide. The presence of the HSP40 co-chaperone Ydj1p has an additive effect on the inhibition of Ure2p fibril formation, whereas the Ydj1p H34Q mutant shows reduced inhibition alone and in combination with Ssa1p. In order to investigate the structural basis of these effects, we constructed and tested an Ssa1p mutant lacking the ATPase domain, as well as a series of C-terminal truncation mutants. The results indicate that Ssa1p can bind to Ure2p and delay fibril formation even in the absence of the ATPase domain, but interaction of Ure2p with the substrate-binding domain is strongly influenced by the C-terminal lid region. Dynamic light scattering, quartz crystal microbalance assays, pull-down assays and kinetic analysis indicate that Ssa1p interacts with both native Ure2p and fibril seeds, and reduces the rate of Ure2p fibril elongation in a concentration-dependent manner. These results provide new insights into the structural and mechanistic basis for inhibition of Ure2p fibril formation by Ssa1p and Ydj1p.
Resumo:
Ure2p is the protein determinant of the Saccharomyces cerevisiae prion state [URE3]. Constitutive overexpression of the HSP70 family member SSA1 cures cells of [URE3]. Here, we show that Ssa1p increases the lag time of Ure2p fibril formation in vitro in the presence or absence of nucleotide. The presence of the HSP40 co-chaperone Ydj1p has an additive effect on the inhibition of Ure2p fibril formation, whereas the Ydj1p H34Q mutant shows reduced inhibition alone and in combination with Ssa1p. In order to investigate the structural basis of these effects, we constructed and tested an Ssa1p mutant lacking the ATPase domain, as well as a series of C-terminal truncation mutants. The results indicate that Ssa1p can bind to Ure2p and delay fibril formation even in the absence of the ATPase domain, but interaction of Ure2p with the substrate-binding domain is strongly influenced by the C-terminal lid region. Dynamic light scattering, quartz crystal microbalance assays, pull-down assays and kinetic analysis indicate that Ssa1p interacts with both native Ure2p and fibril seeds, and reduces the rate of Ure2p fibril elongation in a concentration-dependent manner. These results provide new insights into the structural and mechanistic basis for inhibition of Ure2p fibril formation by Ssa1p and Ydj1p.