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Search Results: 1 - 10 of 23384 matches for " Richard Louis "
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The Evolution of Environmental Policy in the People’s Republic of China
Richard Louis Edmonds
Journal of Current Chinese Affairs , 2011,
Abstract: This paper outlines how the evolution of China’s policy and study of the environment are reflected in the scholarly literature, paying special attention to the impact of the country’s environmental developments on international relations. In particular, it examines accounts of how China has moved from an isolated national scientific and environmental control infrastructure into the centre of international environmental debates as its society has opened and the geographical scale of ecological problems has expanded. The paper also identifies the continuing inhibitors to China’s ability to control environmental degradation – including lack of transparency, elite manipulation, and bureaucratic weaknesses – despite the opening of China’s system to limited participation of civil society in its environmental debates.
Do Black Holes Form?
Richard Gass,Louis Witten
Physics , 1992,
Abstract: We argue that the collapse of a non-rotating object into a black hole has not been proved to be dynamically stable. There are unstable modes and one should explore whether they may be excited. This paper is withdrawn for revisions and clarification
Maximal Ergodic Inequalities for Banach Function Spaces
Richard de Beer,Louis Labuschagne
Mathematics , 2013,
Abstract: We analyse the Transfer Principle, which is used to generate weak type maximal inequalities for ergodic operators, and extend it to the general case of $\sigma$-compact locally compact Hausdorff groups acting measure-preservingly on $\sigma$-finite measure spaces. We show how the techniques developed here generate various weak type maximal inequalities on different Banach function spaces, and how the properties of these function spaces influence the weak type inequalities that can be obtained. Finally, we demonstrate how the techniques developed imply almost sure pointwise convergence of a wide class of ergodic averages.
DNA Polymerase: Structural Homology, Conformational Dynamics, and the Effects of Carcinogenic DNA Adducts
Richard G. Federley,Louis J. Romano
Journal of Nucleic Acids , 2010, DOI: 10.4061/2010/457176
Abstract: DNA replication is vital for an organism to proliferate and lying at the heart of this process is the enzyme DNA polymerase. Most DNA polymerases have a similar three dimensional fold, akin to a human right hand, despite differences in sequence homology. This structural homology would predict a relatively unvarying mechanism for DNA synthesis yet various polymerases exhibit markedly different properties on similar substrates, indicative of each type of polymerase being prescribed to a specific role in DNA replication. Several key conformational steps, discrete states, and structural moieties have been identified that contribute to the array of properties the polymerases exhibit. The ability of carcinogenic adducts to interfere with conformational processes by directly interacting with the protein explicates the mutagenic consequences these adducts impose. Recent studies have identified novel states that have been hypothesised to test the fit of the nascent base pair, and have also shown the enzyme to possess a lively quality by continually sampling various conformations. This review focuses on the homologous structural changes that take place in various DNA polymerases, both replicative and those involved in adduct bypass, the role these changes play in selection of a correct substrate, and how the presence of bulky carcinogenic adducts affects these changes. 1. Introduction Accurate replication of genomic DNA is imperative for the successful proliferation of an organism. The enzyme DNA polymerase is responsible for catalyzing the template-directed addition of a deoxyribonucleoside- -triphosphate (dNTP1) to a growing DNA strand and must do so rapidly and with high fidelity. It is known that the thermodynamics of base pairing alone are insufficient to account for the incredibly low error rates achieved during DNA synthesis [1], and that the DNA polymerase imposes constraints on the selection of a correct nucleotide for incorporation into the primer. Utilizing the thermodynamics of base pairing alone can only account for an accuracy of 1 mistake in 150 nucleotides incorporated, whereas polymerases are known to have error frequencies ranging from to [2, 3]. DNA polymerases must not only ensure accurate synthesis through selection of a correct dNTP, but they also must prevent the incorporation of incorrect substrates such as ribonucleoside- -triphophates (rNTPs). Therefore, a stringent mechanism must be in place for rejection of correctly base pairing nucleotides having a ribose hydroxyl. In addition, some DNA polymerases must cope with reading templates
Estudo de algumas rea??es oxoacidobásicas no solvente NaCl fundido entre 1100K e 1200K
Koeller, Sérgio Luiz;Combes, Richard Louis;
Química Nova , 2002, DOI: 10.1590/S0100-40422002000200010
Abstract: equilibrium constants (k) of some oxoacidbasic reactions in molten nacl in the temperature range of 1100k to 1200k, have been measured potentiometrically with a calcia stabilized zirconia oxide ion (o2-) indicator electrode. in molten nacl at 1100k the pks values (in molality scale) for hcl/h2o and ho-/h2o are respectively 11.0 ± 0.3; 1.6 ± 0.3 and the pks for cao is 4.3 ± 0.3. the results have been compared with those determined previously by combes for the molten equimolar nacl-kcl mixture and are in good agreement with literature data and gives some qualitative explanation of the comparison of oxoacidbasic properties between molten nacl and nacl-kcl.
Solubilidade do SrO em NaCl-Kcl fundido a 727oC
Combes, Richard Louis;Koeller, Sérgio Luiz;
Química Nova , 2000, DOI: 10.1590/S0100-40422000000100008
Abstract: the solubility product value of sro has been found to be equal to 10-4,2 (molality scale) in molten equimolar mixture of nacl and kcl at 727oc, using a potentiometric method involving a calcia stabilized zirconia membrane electrode. this value, which is in a logical agreement with other alkaline-earth oxide determined solubilities, is compared to those of 10-5,8, 10-3,0 and 10-3,08 (molality scale) found in the litterature 33, 22 and 5 years ago, respectively. such discrepencies have called the attention of the authors, their possible reasons (methodology, titrating agent) are analyzed and a theoretical discussion, for considering the authors' value as more reliable, is given in this paper.
Entanglement entropy in particle decay
Lello, Louis;Boyanovsky, Daniel;Holman, Richard
High Energy Physics - Phenomenology , 2013,
Abstract: The decay of a parent particle into two or more daughter particles results in an entangled quantum state, as a consequence of conservation laws in the decay process. We use the Wigner-Weisskopf formalism to construct an approximation to this state that evolves in time in a {\em manifestly unitary} way. We then construct the entanglement entropy for one of the daughter particles by use of the reduced density matrix obtained by tracing out the unobserved states and follow its time evolution. We find that it grows over a time scale determined by the lifetime of the parent particle to a maximum, which when the width of the parent particle is narrow, describes the phase space distribution of maximally entangled Bell-like states.
Solubilidade do SrO em NaCl-Kcl fundido a 727oC
Combes Richard Louis,Koeller Sérgio Luiz
Química Nova , 2000,
Abstract: The solubility product value of SrO has been found to be equal to 10-4,2 (molality scale) in molten equimolar mixture of NaCl and KCl at 727oC, using a potentiometric method involving a calcia stabilized zirconia membrane electrode. This value, which is in a logical agreement with other alkaline-earth oxide determined solubilities, is compared to those of 10-5,8, 10-3,0 and 10-3,08 (molality scale) found in the litterature 33, 22 and 5 years ago, respectively. Such discrepencies have called the attention of the authors, their possible reasons (methodology, titrating agent) are analyzed and a theoretical discussion, for considering the authors' value as more reliable, is given in this paper.
Estudo de algumas rea es oxoacidobásicas no solvente NaCl fundido entre 1100K e 1200K
Koeller Sérgio Luiz,Combes Richard Louis
Química Nova , 2002,
Abstract: Equilibrium constants (K) of some oxoacidbasic reactions in molten NaCl in the temperature range of 1100K to 1200K, have been measured potentiometrically with a calcia stabilized zirconia oxide ion (O2-) indicator electrode. In molten NaCl at 1100K the pKs values (in molality scale) for HCl/H2O and HO-/H2O are respectively 11.0 ± 0.3; 1.6 ± 0.3 and the pKs for CaO is 4.3 ± 0.3. The results have been compared with those determined previously by Combes for the molten equimolar NaCl-KCl mixture and are in good agreement with literature data and gives some qualitative explanation of the comparison of oxoacidbasic properties between molten NaCl and NaCl-KCl.
Superhorizon entanglement entropy from particle decay in inflation
Louis Lello,Daniel Boyanovsky,Richard Holman
Physics , 2013, DOI: 10.1007/JHEP04(2014)055
Abstract: In inflationary cosmology all particle states decay as a consequence of the lack of kinematic thresholds. The decay of an initial single particle state yields an \emph{entangled quantum state of the product particles}. We generalize and extend a manifestly unitary field theoretical method to obtain the time evolution of the quantum state. We consider the decay of a light scalar field with mass $M\ll H$ with a cubic coupling in de Sitter space-time. Radiative corrections feature an infrared enhancement manifest as poles in $\Delta=M^2/3H^2$ and we obtain the quantum state in an expansion in $\Delta$. To leading order in $\Delta$ the pure state density matrix describing the decay of a particle with sub-horizon wavevector is dominated by the emission of superhorizon quanta, describing \emph{entanglement between superhorizon and subhorizon fluctuations and correlations across the horizon}. Tracing over the superhorizon degrees of freedom yields a mixed state density matrix from which we obtain the entanglement entropy. Asymptotically this entropy grows with the \emph{physical} volume as a consequence of more modes of the decay products crossing the Hubble radius. A generalization to localized wave packets is provided. The cascade decay of single particle states into many particle states is discussed. We conjecture on \emph{possible} impact of these results on non-gaussianity and on the ``low multipole anomalies'' of the CMB.
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