1,143 research outputs found

    ‘Risking enchantment’: how are we to view the smoking person?

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    The idea of the smoking person portrayed in public health has been criticised as being based on too narrow a view of human nature. This article discusses that view: that of a person with a stable core and epiphenomenal ‘behaviours’ that can be removed by rational persuasion or Pavlovian manipulation, and examines social scientific critiques of it. The social sciences explore the meanings smoking has for individuals and portray human identity as malleable, the result of ongoing interactions with human and non-human others. Aspects of smokers’ experience revealed in qualitative research – descriptions of cigarettes as ‘companions’ or ‘friends’, deep reliance, sensual pleasure – are sometimes difficult to articulate but can be given full voice in the context of the literary arts. We explore some examples of these sources and argue that a complete picture of smoking meanings is impossible without reference to them. We take a pragmatic approach, following the philosopher William James, who argued that emotional and spiritual experiences contribute to the truth of human existence as much as material explanations, to suggest that this understanding should be part of a critical but supportive engagement with public health research in order to develop more nuanced and humane approaches to smoking cessation

    Book Reviews

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    El Conflicto Honduras-El Salvador y El Orden Juridico Internacional -- On July 14, 1969, the armed forces of El Salvador invaded Honduras... This book provides an almost hourly account of the events preceding the conflict, the war plans executed before the conflict started, the initiation of Inter-American System machinery for settling disputes, the heated discussions among the representatives of the different nations of the OAS, and the consequences of the war itself. Also included is the necessary background on the political and economic conditions prevailing in both countries before the war and a thorough analysis of what role law and international legal machinery played--or might have played--at different stages of the conflict. Reviewed by Jorge L. Carro ============================= United States Foreign Relations Law: Documents and Sources, Vol. 1 (Executive Agreements). Michael J. Glennon and Thomas M. Franck Dobbs Ferry, New York: Oceania Publications, Inc., 1980. Pp. ix, 474. 40.00.-- This volume on United States executive agreements is the first of a multivolume series providing important documents and other materials dealing with the foreign relations power of the federal government and its constituent parts. Reviewed by David S.Clark =========================== Towards a New International Economic Order Mohammed Bedjaoui New York and London: Holmes & Meier Publishers,1979. Pp. 287. 16.50. When tracing the ideologies that animate and condition the current North-South debate over what has come to be called the New International Economic Order, MIT economist Jagdish Bhagwati identifies two dominant schools of thought regarding the existing international economic order. Reviewed by Burns H. Westo

    Changes in the growth mode of electrodeposited silver layers : Surface rearrangements induced by the presence of lead adatoms

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    The surface characteristics of Ag electrodeposits prepared on polyfaceted Pt(sc) electrodes have been followed through complete Pb upd/stripping voltammetry. The growth mode of Ag overlayers at constant temperature depends on both the cathodic electrodeposition overvoltage and the silver ion concentration in solution. Ag surface rearrangements can be induced by either holding the potential or Pb upd/stripping cycling in the potential range where the degree of surface coverage by Pb adatoms is between 0 and 1. The voltammograms of Ag overlayers at the monolayer level show considerable changes compared with those obtained for thicker Ag overlayers. The present results allow us to establish a correlation between the development of rough electrodeposits and the surface diffusion properties of metal atoms.Instituto de Investigaciones FisicoquĂ­micas TeĂłricas y Aplicada

    Electrochemical kinetics and growth modes of silver deposits on polyfaceted platinum spherical electrodes

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    The Ag electrodeposition on Pt spherical substrates was investigated over a wide range of experimental conditions to establish a correlation between the kinetics of the process and the different growth modes of the Ag overlayer. At Ed ≊ Erev, the electrodeposition of the first Ag layer obeys a combined adsorption-desorption and nucleation and 2-D growth process under diffusion control. At Ed ≊ Erev, the formation of the 2-D Ag layer proceeds through an adsorption mechanism, whereas the formation of the 3-D Ag layer fits a progressive nucleation and 3-D growth mechanism under diffusion control. Finally, when Ed rev, a potential threshold related to Ag dendritic growth, the kinetics of the reaction apparently obeys a progressive nucleation and 1-D growth. This process is triggered at edges and corners of large Ag crystals. Dendritic growth takes place outside the diffusion layer defined around the Pt substrate sphere. In this case migration plays a substantial role in the process.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

    Kinetics and Mechanism of Gold Dendrite Electroformation on C(0001) : Activation Energy for Gold Adatom Surface Diffusion

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    Au electrodeposition on C(0001) from aqueous solutions with different concentrations of AuCl3·HCl, at a constant ionic mass transport rate (jL), in the temperature range 275 ≀ T ≀ 313 K, results in the initial formation of nanometer-sized Au islands consisting of a central core and symmetrically distributed branches with the island fractal dimension Df = 1.6. For all values of T, the time dependence of the Au island radius fulfills a r ∝ tn relationship with n = 0.25 ± 0.05. At constant T, the density of Au islands (Ns) increases according to Ns ∝ jLX with X = 0.69 ± 0.03. At constant jL, the value of Ns decreases as T is increased, following an Arrhenius-type relationship. Kinetic data are consistent with a growth mechanism involving surface diffusion of Au adatoms from the island core towards branch tips. From the dependence of Ns on T at constant jL, the activation energy for Au adatom surface diffusion results in Ea* ≈ 11 Kcal/mol. This figure is slightly smaller than Ea* ≈ 14 Kcal/mol that has been reported for Au atom surface diffusion in Cl--ion free acid solutions.Instituto de Investigaciones FisicoquĂ­micas TeĂłricas y Aplicada

    Electrochemical formation of palladium islands on HOPG: Kinetics, morphology, and growth mechanisms

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    Scanning tunneling microscopy (STM) and conventional electrochemical techniques were utilized to investigate the growth kinetics and mechanism of palladium island electroformation on highly oriented pyrolitic graphite (HOPG) from aqueous acid palladium chloride solutions at 298 K. Initially, the electrodeposition reaction at low cathodic overpotentials involves an activation process in which a PdCl2 surface intermediate is formed. At intermediate overpotentials, the growth of palladium islands involves a progressive nucleation and growth model under diffusion control, whereas at high overpotentials, the bulk discharge of soluble palladium species undergoes a free convective-diffusion process. As the cathodic overpotential is shifted negatively, the aspect ratio of the islands, defined as the ratio of the maximum height of the island to the island radius, and the island size decrease, whereas the island density increases. As the cathodic overpotential becomes a few millivolts more positive than the threshold potential of the hydrogen evolution reaction, the island shape changes from a compact disk to a quasi-2D dense radial Pd(111) island. The formation of a dense radial morphology and its small departure from a perfect 2D pattern indicates the presence of weak step-edge energy barriers, as expected from theoretical calculations for Pd(111). These results stress the key role of step-edge energy barriers in determining growth patterns during metal electrodeposition.Instituto de Investigaciones FisicoquĂ­micas TeĂłricas y AplicadasFacultad de Ciencias Exacta

    Growth mode transition involving a potential-dependent isotropic to anisotropic surface atom diffusion change. Gold electrodeposition on HOPG followed by STM

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    The electrodeposition of gold on highly oriented pyrolytic graphite (HOPG) from acid aqueous solutions was studied by using electrochemical techniques complemented with ex-situ scanning tunneling microscopy (STM). The kinetics of gold electrodeposition is consistent with a nucleation and three-dimensional growth process under diffusion control from the solution side. As the applied potential moves in the negative direction, the gold crystal density increases, and the crystal shape changes from a Euclidean to a dendritic fractal morphology. This transition can be assigned to the anisotropic surface diffusion of gold adatoms induced by the applied electric potential. A model including a potential-dependent energy barrier at step edges accounts for the morphology transition for gold electrodeposition on HOPG.Instituto de Investigaciones FisicoquĂ­micas TeĂłricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

    Growth of three-dimensional silver fractal electrodeposits under damped free convection

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    Quasispherical three-dimensional Ag electrodeposits grown at constant potential and damped free convection exhibit a quasi-isotropic radial growth up to a critical radius rc≃0.3 cm and a mass fractal dimension DM=2.5. For r≫rc, DM→3. The product vrη’ is nearly constant, vr being the radial growth velocity, and η’ the apparent medium viscosity. It appears that vr is determined by the Laplacian field operating between cathode and anode.Instituto de Investigaciones FisicoquĂ­micas TeĂłricas y Aplicada
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