WorldWideScience

Sample records for chemical theory impact

  1. Impact of solar system exploration on theories of chemical evolution and the origin of life

    Science.gov (United States)

    Devincenzi, D. L.

    1983-01-01

    The impact of solar system exploration on theories regarding chemical evolution and the origin of life is examined in detail. Major findings from missions to Mercury, Venus, the moon, Mars, Jupiter, Saturn, and Titan are reviewed and implications for prebiotic chemistry are discussed. Among the major conclusions are: prebiotic chemistry is widespread throughout the solar system and universe; chemical evolution and the origin of life are intimately associated with the origin and evolution of the solar system; the rate, direction, and extent of prebiotic chemistry is highly dependent upon planetary characteristics; and continued exploration will increase understanding of how life originated on earth and allow better estimates of the likelihood of similar processes occurring elsewhere.

  2. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    1969-01-01

    High Resolution NMR: Theory and Chemical Applications focuses on the applications of nuclear magnetic resonance (NMR), as well as chemical shifts, lattices, and couplings. The book first offers information on the theory of NMR, including nuclear spin and magnetic moment, spin lattice relaxation, line widths, saturation, quantum mechanical description of NMR, and ringing. The text then ponders on instrumentation and techniques and chemical shifts. Discussions focus on the origin of chemical shifts, reference compounds, empirical correlations of chemical shifts, modulation and phase detection,

  3. Quasi-chemical Theories of Associated Liquids

    CERN Document Server

    Pratt, L R; Pratt, Lawrence R.; Violette, Randall A. La

    1998-01-01

    It is shown how traditional development of theories of fluids based upon the concept of physical clustering can be adapted to an alternative local clustering definition. The alternative definition can preserve a detailed valence description of the interactions between a solution species and its near-neighbors, i.e., cooperativity and saturation of coordination for strong association. These clusters remain finite even for condensed phases. The simplest theory to which these developments lead is analogous to quasi-chemical theories of cooperative phenomena. The present quasi-chemical theories require additional consideration of packing issues because they don't impose lattice discretizations on the continuous problem. These quasi-chemical theories do not require pair decomposable interaction potential energy models. Since calculations may be required only for moderately sized clusters, we suggest that these quasi-chemical theories could be implemented with computational tools of current electronic structure the...

  4. Chemical organization theory: towards a theory of constructive dynamical systems

    OpenAIRE

    Dittrich, Peter; di Fenizio, Pietro Speroni

    2005-01-01

    Complex dynamical networks consisting of many components that interact and produce each other are difficult to understand, especially, when new components may appear. In this paper we outline a theory to deal with such systems. The theory consists of two parts. The first part introduces the concept of a chemical organization as a closed and mass-maintaining set of components. This concept allows to map a complex (reaction) network to the set of organizations, providing a new view on the syste...

  5. A Unified Theory of Chemical Reactions

    CERN Document Server

    Aubry, S

    2014-01-01

    We propose a new and general formalism for elementary chemical reactions where quantum electronic variables are used as reaction coordinates. This formalism is in principle applicable to all kinds of chemical reactions ionic or covalent. Our theory reveals the existence of an intermediate situation between ionic and covalent which may be almost barrierless and isoenegetic and which should be of high interest for understanding biochemistry.

  6. Impact of Artificial Intelligence on Economic Theory

    OpenAIRE

    Tshilidzi Marwala

    2015-01-01

    Artificial intelligence has impacted many aspects of human life. This paper studies the impact of artificial intelligence on economic theory. In particular we study the impact of artificial intelligence on the theory of bounded rationality, efficient market hypothesis and prospect theory.

  7. Using chemical organization theory for model checking

    OpenAIRE

    Kaleta, Christoph; Richter, Stephan; Dittrich, Peter

    2009-01-01

    Motivation: The increasing number and complexity of biomodels makes automatic procedures for checking the models' properties and quality necessary. Approaches like elementary mode analysis, flux balance analysis, deficiency analysis and chemical organization theory (OT) require only the stoichiometric structure of the reaction network for derivation of valuable information. In formalisms like Systems Biology Markup Language (SBML), however, information about the stoichiometric coefficients re...

  8. College Impact Theories Past and Present

    Science.gov (United States)

    Ozaki, C. Casey

    2016-01-01

    This chapter critically examines the fit and applicability of foundational college impact theories to the community college context and students. Implications for the literature and campuses are explored.

  9. Molecular orbital calculations using chemical graph theory

    CERN Document Server

    Dias, Jerry Ray

    1993-01-01

    Professor John D. Roberts published a highly readable book on Molecular Orbital Calculations directed toward chemists in 1962. That timely book is the model for this book. The audience this book is directed toward are senior undergraduate and beginning graduate students as well as practicing bench chemists who have a desire to develop conceptual tools for understanding chemical phenomena. Although, ab initio and more advanced semi-empirical MO methods are regarded as being more reliable than HMO in an absolute sense, there is good evidence that HMO provides reliable relative answers particularly when comparing related molecular species. Thus, HMO can be used to rationalize electronic structure in 1t-systems, aromaticity, and the shape use HMO to gain insight of simple molecular orbitals. Experimentalists still into subtle electronic interactions for interpretation of UV and photoelectron spectra. Herein, it will be shown that one can use graph theory to streamline their HMO computational efforts and to arrive...

  10. Phase evolution theory for polymer blends with extreme chemical dispersity: parameterization of DDFT simulations and application to poly(propylene) impact copolymers

    NARCIS (Netherlands)

    Fraaije, J.G.E.M.; Nath, S.K.; Remerie, K.; Groenewold, J.

    2011-01-01

    DDFT is applied to phase formation in homopolymer/copolymer blends in which the copolymer is extremely disperse with a uniform chemical composition distribution. Such systems develop a core/shell structure with a thick interface. This study is motivated by peculiarities in the phase evolution of ind

  11. Chemical applications of molecular quantum theory

    International Nuclear Information System (INIS)

    Molecular systems of chemical interest are investigated with the aid of molecular quantum theory. The self-consistent field (SCF) method is used to predict the molecular structures of ClF2, ClF4 and Cl3 radicals, and the ions ClF2+, ClF2-, ClF4+ and ClF4-. The ClF2 and Cl3 radicals are predicted to be bent with bond angles of 145.20 and 158.60, respectively, while the ions ClF2+ and ClF2- are predicted to be bent with a bond angle of 97.40 and linear, respectively. The geometry predictions for the ClF4 radical and the ClF4+ ion are found to be notably basis set dependent. The ClF4- ion is predicted to be square-planar. Multi-configuration self-consistent field (MCSCF) calculations have yielded the dipole moment function for the 1sigma+ state of HI, which qualitatively confirms the experimental finding that the dipole derivative at R/sub e/ is negative. The 2sigma+ F + H2 potential energy surface is studied extensively with the configuration interaction (CI) method. The most complete calculations yield an activation energy of 2.74 kcal/mole and an exothermicity of 30.0 kcal/mole. The production of a potential energy surface of ''chemical accuracy'' for this system is found to be more difficult than previously believed. The simplest hydrophobic model, the water-methane system, is studied with the SCF method in order to determine the nature and magnitude of the interaction. The most favorable geometric arrangement corresponds to an attraction of 0.5 kcal/mole

  12. Trends in information theory-based chemical structure codification.

    Science.gov (United States)

    Barigye, Stephen J; Marrero-Ponce, Yovani; Pérez-Giménez, Facundo; Bonchev, Danail

    2014-08-01

    This report offers a chronological review of the most relevant applications of information theory in the codification of chemical structure information, through the so-called information indices. Basically, these are derived from the analysis of the statistical patterns of molecular structure representations, which include primitive global chemical formulae, chemical graphs, or matrix representations. Finally, new approaches that attempt to go "back to the roots" of information theory, in order to integrate other information-theoretic measures in chemical structure coding are discussed.

  13. Practical impact of group communication theory

    OpenAIRE

    Schiper, A.

    2003-01-01

    Practical impact of group communication theory Andre Schiper Group communication is an important topic in fault-tolerant distributed applications. The paper summarizes the main contributions of practical importance that contributed to our current understanding of group communication. These contributions are classified into ''abstractions'' and ''specifications'', ''paradigms'', ''system models'', ''algorithms'', and ''theoretical results''. Some open issues are discussed at the end of the ...

  14. CALCULATION AND APPLICATION OF ENVIRONMENTAL IMPACT INDEX OF CHEMICAL COMPOUND BASED ON FUZZY OPTIMAL SELECTION THEORY%基于多目标模糊优选理论的化合物环境影响指数确定及应用

    Institute of Scientific and Technical Information of China (English)

    孙力; 贺高红; 樊希山; 姚平经

    2004-01-01

    Environment impact (EI) is a multi- decision-making, multi-objective and multi-criteria system with uncertainties and ambiguities, and environment impact index (EII) of a chemical compound is difficult to calculate appropriately with traditional methods. In this paper, fuzzy optimal selection theory based on the concept of relative importance degree is adopted to determine relativity of the degree of environment impact of chemical compounds as EII, and environment impact assessment (EIA) of a chemical process is done with values of compounds EII to select alternatives that cause less pollution to the environment. It is useful in further process optimization. The paper presents a practical application to the treatment of process condensate in a synthesis ammonia plant to illustrate the procedure, and the calculation result demonstrates the feasibility, practicability, and effectiveness of the suggested method.

  15. Using game theory to improve safety within chemical industrial parks

    CERN Document Server

    Reniers, Genserik

    2013-01-01

    Though the game-theoretic approach has been vastly studied and utilized in relation to economics of industrial organizations, it has hardly been used to tackle safety management in multi-plant chemical industrial settings. Using Game Theory for Improving Safety within Chemical Industrial Parks presents an in-depth discussion of game-theoretic modelling which may be applied to improve cross-company prevention and -safety management in a chemical industrial park.   By systematically analyzing game-theoretic models and approaches in relation to managing safety in chemical industrial parks, Using Game Theory for Improving Safety within Chemical Industrial Parks explores the ways game theory can predict the outcome of complex strategic investment decision making processes involving several adjacent chemical plants. A number of game-theoretic decision models are discussed to provide strategic tools for decision-making situations.   Offering clear and straightforward explanations of methodologies, Using Game Theor...

  16. Quasi-chemical Theories of Associated Liquids

    OpenAIRE

    Pratt, Lawrence R.; LaViolette, Randall A.

    1998-01-01

    It is shown how traditional development of theories of fluids based upon the concept of physical clustering can be adapted to an alternative local clustering definition. The alternative definition can preserve a detailed valence description of the interactions between a solution species and its near-neighbors, i.e., cooperativity and saturation of coordination for strong association. These clusters remain finite even for condensed phases. The simplest theory to which these developments lead i...

  17. The correlation theory of the chemical bond

    CERN Document Server

    Szalay, Szilárd; Szilvási, Tibor; Veis, Libor; Legeza, Örs

    2016-01-01

    The notion of chemical bond is a very useful concept in chemistry. It originated at the beginning of chemistry, it is expressive for the classically thinking mind, and the errors arising from the approximative nature of the concept can often be ignored. In the first half of the twentieth century, however, we learned that the proper description of the microworld is given by quantum mechanics. Quantum mechanics gives more accurate results for chemical systems than any preceding model, however, it is very inexpressive for the classically thinking mind. The quantum mechanical description of the chemical bond is given in terms of delocalized bonding orbitals, or, alternatively, in terms of correlations of occupations of localized orbitals. However, in the latter case, multiorbital correlations were treated only in terms of two-orbital correlations, although the structure of multiorbital correlations is far richer; and, in the case of bonds established by more than two electrons, multiorbital correlations represent...

  18. Impact damage assessment by using peridynamic theory

    Science.gov (United States)

    Oterkus, Erkan; Guven, Ibrahim; Madenci, Erdogan

    2012-12-01

    This study presents an application of peridynamic theory for predicting residual strength of impact damaged building components by considering a reinforced panel subjected to multiple load paths. The validity of the approach is established first by simulating a controlled experiment resulting in mixed-mode fracture of concrete. The agreement between the PD prediction and the experimentally observed behavior is remarkable especially considering the simple material model used for the concrete. Subsequently, the PD simulation concerns damage assessment and residual strength of a reinforced panel under compression after impact due to a rigid penetrator.

  19. Closing in on chemical bonds by opening up relativity theory.

    Science.gov (United States)

    Whitney, Cynthia K

    2008-03-01

    This paper develops a connection between the phenomenology of chemical bonding and the theory of relativity. Empirical correlations between electron numbers in atoms and chemical bond stabilities in molecules are first reviewed and extended. Quantitative chemical bond strengths are then related to ionization potentials in elements. Striking patterns in ionization potentials are revealed when the data are viewed in an element-independent way, where element-specific details are removed via an appropriate scaling law. The scale factor involved is not explained by quantum mechanics; it is revealed only when one goes back further, to the development of Einstein's special relativity theory. PMID:19325749

  20. Closing in on chemical bonds by opening up relativity theory.

    Science.gov (United States)

    Whitney, Cynthia K

    2008-03-01

    This paper develops a connection between the phenomenology of chemical bonding and the theory of relativity. Empirical correlations between electron numbers in atoms and chemical bond stabilities in molecules are first reviewed and extended. Quantitative chemical bond strengths are then related to ionization potentials in elements. Striking patterns in ionization potentials are revealed when the data are viewed in an element-independent way, where element-specific details are removed via an appropriate scaling law. The scale factor involved is not explained by quantum mechanics; it is revealed only when one goes back further, to the development of Einstein's special relativity theory.

  1. On the theory of time dilation in chemical kinetics

    CERN Document Server

    Baig, Mirza Wasif

    2012-01-01

    The rates of chemical reactions are not absolute but their magnitude depends upon the relative speeds of the moving observers. This has been proved by unifying theories of chemical kinetics, which are transition state theory, collision theory and Marcus theory, with the special theory of relativity. Lorentz transformations of Boltzmann constant and energy spacing between permitted quantum levels of molecules are quantum mechanically proved to be Lorentz variant. The relativistic statistical thermodynamics has been developed to explain quasiequilibrium existing between reactants and activated complex. The newly formulated Lorentz transformation of the rate constant from Arrhenius Equation, of the collision frequency and of the Eyring and Marcus equations renders the rate law also Lorentz variant. For a moving observer moving at fractions of the speed of light along the reaction coordinate the transition state possess less kinetic energy to sweep translation over it. This results in the slower transformation of...

  2. Three-dimensional DEM theory and its application to impact mechanics

    Institute of Scientific and Technical Information of China (English)

    唐志平

    2001-01-01

    In this paper, three-dimensional (3D) DEM theory has been explored and applied to impact simulation. The calculated results fit the experimental observation quite well, showing that this method can be applied to the simulation of the impact responses and the analysis of the mechanisms for materials and structures with defects, heterogeneity, multi-phase, even with phase and chemical changes.

  3. Chemical Abstracts Service Chemical Registry System: History, Scope, and Impacts.

    Science.gov (United States)

    Weisgerber, David W.

    1997-01-01

    Describes the history, scope, and applications of the Chemical Abstracts Service Chemical Registry System, a computerized database that uniquely identifies chemical substances on the basis of their molecular structures. Explains searching the system is and discusses its use as an international resource. (66 references) (Author/LRW)

  4. Closing in on Chemical Bonds by Opening up Relativity Theory

    Directory of Open Access Journals (Sweden)

    Cynthia Kolb Whitney

    2008-03-01

    Full Text Available This paper develops a connection between the phenomenology of chemical bonding and the theory of relativity. Empirical correlations between electron numbers in atoms and chemical bond stabilities in molecules are first reviewed and extended. Quantitative chemical bond strengths are then related to ionization potentials in elements. Striking patterns in ionization potentials are revealed when the data are viewed in an element-independent way, where element-specific details are removed via an appropriate scaling law. The scale factor involved is not explained by quantum mechanics; it is revealed only when one goes back further, to the development of Einstein’s special relativity theory.

  5. Monoamine theories of depression: historical impact on biomedical research.

    Science.gov (United States)

    Mulinari, Shai

    2012-01-01

    Monoamine theories associate depression with reduced brain monoamine levels. These theories achieved broad popularity in the mid-1960s. The present article reviews the historical development of monoamine theories and their subsequent impact on biomedical research. Alleged divisions between West European and US researchers over competing versions of the theories are investigated using bibliometrics. Subsequently, the application of monoamine theories in the NIMH Collaborative Program on the Psychobiology of Depression is covered. The article argues that the impact of monoamine theories is best explained by the ability of researchers, governmental agencies, and pharmaceutical companies to invoke theories that advance various projects and agendas.

  6. Mesoscopic Kinetic Basis of Macroscopic Chemical Thermodynamics: A Mathematical Theory

    CERN Document Server

    Ge, Hao

    2016-01-01

    From a mathematical model that describes a complex chemical kinetic system of $N$ species and $M$ elementrary reactions in a rapidly stirred vessel of size $V$ as a Markov process, we show that a macroscopic chemical thermodynamics emerges as $V\\rightarrow\\infty$. The theory is applicable to linear and nonlinear reactions, closed systems reaching chemical equilibrium, or open, driven systems approaching to nonequilibrium steady states. A generalized mesoscopic free energy gives rise to a macroscopic chemical energy function $\\varphi^{ss}(\\vx)$ where $\\vx=(x_1,\\cdots,x_N)$ are the concentrations of the $N$ chemical species. The macroscopic chemical dynamics $\\vx(t)$ satisfies two emergent laws: (1) $(\\rd/\\rd t)\\varphi^{ss}[\\vx(t)]\\le 0$, and (2)$(\\rd/\\rd t)\\varphi^{ss}[\\vx(t)]=\\text{cmf}(\\vx)-\\sigma(\\vx)$ where entropy production rate $\\sigma\\ge 0$ represents the sink for the chemical energy, and chemical motive force $\\text{cmf}\\ge 0$ is non-zero if the system is driven under a sustained nonequilibrium chemos...

  7. Theory of nanoscale friction on chemically modified graphene

    Science.gov (United States)

    Ko, Jae-Hyeon; Kim, Yong-Hyun

    2013-03-01

    Recently, it is known from FFM experiments that friction force on graphene is significantly increased by chemical modification such as hydrogenation, oxidization, and fluorination, whereas adhesion properties are altered marginally. A novel nanotribological theory on two-dimensional materials is proposed on the basis of experimental results and first-principles density-functional theory (DFT) calculations. The proposed theory indicates that the total lateral stiffness that is the proportional constant of friction force is mostly associated with the out-of-plane bending stiffness of two-dimensional materials. This contrasts to the case of three-dimensional materials, in which the shear strength of materials determines nanoscale friction. We will discuss details of DFT calculations and how to generalize the current theory to three dimensional materials.

  8. Impact of Deconstruction on Translation Theory

    Institute of Scientific and Technical Information of China (English)

    庄浩

    2009-01-01

    Deconstruction theory is a translation theory which is worthy our great attention. This paper expounds the effects of deconstruction theory on translation theory and practice, points out the limitations of the theory, and puts forward the necessity to construct a new translation standard after deconstruction. The ideas and methods it illustrated bring us many new inspirations, which have important reference value and significance to reconstruct Chinese translation theory.

  9. Financial Crisis 2008 Impact on China Chemical Fiber Industry

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    On Jun. 10-12, 2009, The 15th China’s International Chemical Fiber Conference, with the theme of "Financial Crisis and Chemical Fiber Industry", was held at Hangzhou, Zhejiang Province. During the conference, the China Chemical Fiber Association released a speech on "The Impact of Global Financial Crisis on China Chemical Fiber Industry and Response Strategies". Here in the following part, we will focus on the part of the impact of financial crisis on Chinese chemical fiber industry. In our next issue, we will go on with the part of Response Strategies.

  10. Fourth-Order Vibrational Transition State Theory and Chemical Kinetics

    Science.gov (United States)

    Stanton, John F.; Matthews, Devin A.; Gong, Justin Z.

    2015-06-01

    Second-order vibrational perturbation theory (VPT2) is an enormously successful and well-established theory for treating anharmonic effects on the vibrational levels of semi-rigid molecules. Partially as a consequence of the fact that the theory is exact for the Morse potential (which provides an appropriate qualitative model for stretching anharmonicity), VPT2 calculations for such systems with appropriate ab initio potential functions tend to give fundamental and overtone levels that fall within a handful of wavenumbers of experimentally measured positions. As a consequence, the next non-vanishing level of perturbation theory -- VPT4 -- offers only slight improvements over VPT2 and is not practical for most calculations since it requires information about force constants up through sextic. However, VPT4 (as well as VPT2) can be used for other applications such as the next vibrational correction to rotational constants (the ``gammas'') and other spectroscopic parameters. In addition, the marriage of VPT with the semi-classical transition state theory of Miller (SCTST) has recently proven to be a powerful and accurate treatment for chemical kinetics. In this talk, VPT4-based SCTST tunneling probabilities and cumulative reaction probabilities are give for the first time for selected low-dimensional model systems. The prospects for VPT4, both practical and intrinsic, will also be discussed.

  11. The Impact of Price on Chemical Fertilizer Demand in China

    OpenAIRE

    Huang, Wen-fang; Du, Cheng; John K. Dagsvik

    2012-01-01

    Since 1998, the national policies on chemical fertilizer in China have been concentrated in limiting price plus subsidizing, abolishing agricultural tax, giving direct subsidies to farmers, and other aspects. In order to analyze the impact of national policies on the consumption of chemical fertilizer, this article selects the consumption of chemical fertilizer per unit, chemical fertilizer price index and farmers' net income in different provinces during the period 1998-2007 as variables, to...

  12. Chemical Graph Theory and the Sherlock Holmes Principle

    Directory of Open Access Journals (Sweden)

    Alexandru T. Balaban

    2013-07-01

    Full Text Available The development of chemical applications of graph theory is reviewed from a personal perspective. Graph-theoretical methods for finding all graphs fulfilling certain mathematical conditions followed by eliminating chemically impossible solutions are equivalent to the ‘Sherlock Holmes principle’. For molecular graphs, this is illustrated by monocyclic aromatic systems and by valence isomers of annulenes. Using dualist graphs for benzenoids and diamond hydrocarbons it was possible to develop simple encoding systems that allowed convenient enumerations of isomers. Starting with the invention of reaction graphs in 1966 that included the Petersen graph which is also the 5-cage (the smallest graph with girth 5 two gaps were filled by discovering the first 10-cage and the unique 11-cage, showing how chemical clues can lead to interesting mathematical developments. Graphs of a third type are represented by synthon graphs that are helping chemical synthesis. Connections between chemical structure and molecular properties allow the design of biologically active substances on the basis of quantitative structure-activity relationships (QSARs. Some of the simplest tools for QSAR are topological indices and they are briefly discussed.

  13. Chemical reactions modulated by mechanical stress: extended Bell theory.

    Science.gov (United States)

    Konda, Sai Sriharsha M; Brantley, Johnathan N; Bielawski, Christopher W; Makarov, Dmitrii E

    2011-10-28

    A number of recent studies have shown that mechanical stress can significantly lower or raise the activation barrier of a chemical reaction. Within a common approximation due to Bell [Science 200, 618 (1978)], this barrier is linearly dependent on the applied force. A simple extension of Bell's theory that includes higher order corrections in the force predicts that the force-induced change in the activation energy will be given by -FΔR - ΔχF(2)∕2. Here, ΔR is the change of the distance between the atoms, at which the force F is applied, from the reactant to the transition state, and Δχ is the corresponding change in the mechanical compliance of the molecule. Application of this formula to the electrocyclic ring-opening of cis and trans 1,2-dimethylbenzocyclobutene shows that this extension of Bell's theory essentially recovers the force dependence of the barrier, while the original Bell formula exhibits significant errors. Because the extended Bell theory avoids explicit inclusion of the mechanical stress or strain in electronic structure calculations, it allows a computationally efficient characterization of the effect of mechanical forces on chemical processes. That is, the mechanical susceptibility of any reaction pathway is described in terms of two parameters, ΔR and Δχ, both readily computable at zero force.

  14. Renormalization group theory impact on experimental magnetism

    CERN Document Server

    Köbler, Ulrich

    2010-01-01

    Spin wave theory of magnetism and BCS theory of superconductivity are typical theories of the time before renormalization group (RG) theory. The two theories consider atomistic interactions only and ignore the energy degrees of freedom of the continuous (infinite) solid. Since the pioneering work of Kenneth G. Wilson (Nobel Prize of physics in 1982) we know that the continuous solid is characterized by a particular symmetry: invariance with respect to transformations of the length scale. Associated with this symmetry are particular field particles with characteristic excitation spectra. In diamagnetic solids these are the well known Debye bosons. This book reviews experimental work on solid state physics of the last five decades and shows in a phenomenological way that the dynamics of ordered magnets and conventional superconductors is controlled by the field particles of the infinite solid and not by magnons and Cooper pairs, respectively. In the case of ordered magnets the relevant field particles are calle...

  15. Endocrine Disrupting Chemical Impacts on Aquatic Systems

    Science.gov (United States)

    Jobling, Susan

    2014-07-01

    We often talk about the importance of water, but one area that's often overlooked is the safety of our water supply. How many people actually think about the purity of their water when they turn on the tap? We may have real reason to be concerned because our water delivery systems and treatment technology seem to be stuck in the past, relying on old water treatment and water delivery systems. While these systems still do a great job filtering out particles, parasites and bacteria, they usually fail to remove 21st century contaminants like pesticides, industrial chemicals, lead, pharmaceuticals and arsenic. Indeed our water contains already a whole plethora of things in daily commerce and pharmaceuticals are increasingly showing up in the water supply, including antibiotics, anti-convulsants, mood altering medications and sex hormones. As the world's dependence on chemicals grows, our water supplies will continue to feel the effects, which inevitably will touch every person on this planet...

  16. Impact of oil on groundwater chemical composition

    Science.gov (United States)

    Brakorenko, N. N.

    2015-11-01

    The objective of the paper is to characterize the chemical composition of groundwater samples from the monitoring wells drilled in the petrol station areas within the vicinity of Tomsk. The level of contamination has increased since many macro - and microcomponent concentrations (such as petroleum products, chlorine, sulphates, carbon dioxide and lead, etc.) in groundwater samples of the present study is higher than that in previous period samples.

  17. VERIFICATION OF SOCIAL IMPACT THEORY CLAIMS IN SOCIAL MEDIA CONTEXT

    OpenAIRE

    Imran Mir; Arshad Zaheer

    2012-01-01

    Social media explosion changed the way of communication. It affected the ways companies used to interact with their consumers. Most important it changed the way consumers used to think. Present study attempts to verify the claims and assumptions of social impact theory in the social media environment. Based on social impact theory present study examines the impa ct of number of users (NUs) on the perceived credibility of user generated content (PCUGC). Furthermo re, ...

  18. VERIFICATION OF SOCIAL IMPACT THEORY CLAIMS IN SOCIAL MEDIA CONTEXT

    Directory of Open Access Journals (Sweden)

    Imran Mir

    2012-04-01

    Full Text Available Social media explosion changed the way of communication. It affected the ways companies used to interact with their consumers. Most important it changed the way consumers used to think. Present study attempts to verify the claims and assumptions of social impact theory in the social media environment. Based on social impact theory present study examines the impa ct of number of users (NUs on the perceived credibility of user generated content (PCUGC. Furthermo re, it examines the impact of PCUGC on the consumer attitude towards the product related content embedded in UGC (ATUGC. Empirical evidence was collected from a random sample of 459 students. Results substantiate the claims and assumptions of the social impact theory in the social media context. Results show positive impact of NUs on PCUGC. Similarly, they show positive relationship between PCUGC and ATUGC

  19. Potential Impacts of Spilled Hydraulic Fracturing Fluid Chemicals on Water Resources: Types, volumes, and physical-chemical properties of chemicals

    Science.gov (United States)

    Hydraulic fracturing (HF) fluid chemicals spilled on-site may impact drinking water resources. While chemicals generally make up <2% of the total injected fluid composition by mass, spills may have undiluted concentrations. HF fluids typically consist of a mixture of base flui...

  20. Density versus chemical potential in holographic field theories

    CERN Document Server

    Nogueira, Fernando

    2011-01-01

    We study the relationship between charge density ({\\rho}) and chemical potential ({\\mu}) for an array of Lorentz invariant 3 + 1 dimensional holographic field theories with the minimal structure of a conserved charge. The systems considered include Dp-Dq probe brane constructions and probe and backreacted 'bottom-up' models with gauge and scalar fields. In all cases, at large density, the relationship is well modelled by a power law behaviour of the form {\\rho} $\\propto$ {\\mu}^{\\alpha}. A variety of powers {\\alpha} are found in the brane systems while in most of the bottom-up models {\\alpha} is determined by the underlying conformal symmetry. Further, it is demonstrated that basic thermodynamical and causality constraints demand {\\alpha} \\geq 1, a condition that was realized in each system considered.

  1. The Impact of Price on Chemical Fertilizer Demand in China

    Institute of Scientific and Technical Information of China (English)

    John K.Dagsvik

    2012-01-01

    Since 1998,the national policies on chemical fertilizer in China have been concentrated in limiting price plus subsidizing,abolishing agricultural tax,giving direct subsidies to farmers,and other aspects.In order to analyze the impact of national policies on the consumption of chemical fertilizer,this article selects the consumption of chemical fertilizer per unit,chemical fertilizer price index and farmers’net income in different provinces during the period 1998-2007 as variables,to conduct regression analysis of chemical fertilizer expenditure function,and calculate the price elasticity and income elasticity of chemical fertilizer demand in different provinces over the decade based on the regression results.The results show that at present the basic consumption of chemical fertilizer for agricultural development in China is 0.35 t/hm 2 ,and the consumption of chemical fertilizer is excessive in some provinces;the chemical fertilizer market has not been really established,and the price has little impact on demand.This indicates that the chemical fertilizer is essential for agricultural economic development,and it increases along with the increase of farmers’income; the intervention of the national policy in chemical fertilizer price is a fundamental reason for the rising demand for chemical fertilizer.This also to some extent indicates that the policy effect of merely using environmental taxes to change farmers’consumption of chemical fertilizer is limited;there is a need to transform the existing policies purely promoting agricultural economic development,toward giving different subsidies in accordance with whether the farmers’fertilization pattern is beneficial to the environment.

  2. Theory of rotational transition in atom-diatom chemical reaction

    Science.gov (United States)

    Nakamura, Masato; Nakamura, Hiroki

    1989-05-01

    Rotational transition in atom-diatom chemical reaction is theoretically studied. A new approximate theory (which we call IOS-DW approximation) is proposed on the basis of the physical idea that rotational transition in reaction is induced by the following two different mechanisms: rotationally inelastic half collision in both initial and final arrangement channels, and coordinate transformation in the reaction zone. This theory gives a fairy compact expression for the state-to-state transition probability. Introducing the additional physically reasonable assumption that reaction (particle rearrangement) takes place in a spatially localized region, we have reduced this expression into a simpler analytical form which can explicitly give overall rotational state distribution in reaction. Numerical application was made to the H+H2 reaction and demonstrated its effectiveness for the simplicity. A further simplified most naive approximation, i.e., independent events approximation was also proposed and demonstrated to work well in the test calculation of H+H2. The overall rotational state distribution is expressed simply by a product sum of the transition probabilities for the three consecutive processes in reaction: inelastic transition in the initial half collision, transition due to particle rearrangement, and inelastic transition in the final half collision.

  3. Quasi-chemical Theory for the Statistical Thermodynamics of the Hard Sphere Fluid

    OpenAIRE

    Pratt, Lawrence R.; LaViolette, Randall A.; Gomez, Maria A.; Gentile, Mary E.

    2001-01-01

    We develop a quasi-chemical theory for the study of packing thermodynamics in dense liquids. The situation of hard-core interactions is addressed by considering the binding of solvent molecules to a precisely defined `cavity' in order to assess the probability that the `cavity' is entirely evacuated. The primitive quasi-chemical approximation corresponds to a extension of the Poisson distribution used as a default model in an information theory approach. This primitive quasi-chemical theory i...

  4. A Theory of Decomposition of Complex Chemical Networks using the Hill Functions

    CERN Document Server

    Chikayama, Eisuke

    2014-01-01

    The design and synthesis of complex and large mimicked biochemical networks de novo is an unsolved problem in synthetic biology. To address this limitation without resorting to ad hoc computations and experiments, a predictive mathematical theory is required to reduce these complex chemical networks into natural physico-chemical expressions. Here we provide a mathematical theory that offers a physico-chemical expression for a large chemical network that is almost arbitrarily both nonlinear and complex. Unexpectedly, the theory demonstrates that such networks can be decomposed into reactions based solely on the Hill equation, a simple chemical logic gate. This theory, analogous to implemented electrical logic gates or functional algorithms in a computer, is proposed for implementing regulated sequences of functional chemical reactions, such as mimicked genes, transcriptional regulation, signal transduction, protein interaction, and metabolic networks, into an artificial designed chemical network.

  5. The Impact of Flow Injection on Modern Chemical Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    There is no doubt that Flow Injection Analysis (FIA) has had a profound impact on the ways and means that modern analytical chemical procedures are performed. This is amply reflected in the voluminous scientific literature, which by the middle of 2004 passed more than 14,500 FIA-publications in i......There is no doubt that Flow Injection Analysis (FIA) has had a profound impact on the ways and means that modern analytical chemical procedures are performed. This is amply reflected in the voluminous scientific literature, which by the middle of 2004 passed more than 14,500 FIA...... and preconcentration procedures. In recent years, FIA has been supplemented by Sequential Injection Analysis (SIA) and the Lab-on-Valve (LOV) approach. Following a brief historic introduction and an account of the impact of FIA in academia, the lecture will describe these two new generations of FIA, accompanied...

  6. 76 FR 76935 - Impact of Implementing the Chemical Weapons Convention (CWC) on Commercial Activities Involving...

    Science.gov (United States)

    2011-12-09

    ... Bureau of Industry and Security Impact of Implementing the Chemical Weapons Convention (CWC) on... implementation of the Chemical Weapons Convention (CWC), through the Chemical Weapons Convention Implementation Act (CWCIA), and the Chemical Weapons Convention Regulations (CWCR), has had on commercial...

  7. Concept of REACH and impact on evaluation of chemicals.

    Science.gov (United States)

    Foth, H; Hayes, Aw

    2008-01-01

    Industrial chemicals have been in use for many decades and new products are regularly invented and introduced to the market. Also for decades, many different chemical laws have been introduced to regulate safe handling of chemicals in different use patterns. The patchwork of current regulation in the European Union is to be replaced by the new regulation on industrial chemical control, REACH. REACH stands for registration, evaluation, and authorization of chemicals. REACH entered force on June 1, 2007. REACH aims to overcome limitations in testing requirements of former regulation on industrial chemicals to enhance competitiveness and innovation with regard to manufacture safer substances and to promote the development of alternative testing methods. A main task of REACH is to address data gaps regarding the properties and uses of industrial chemicals. Producers, importers, and downstream users will have to compile and communicate standard information for all chemicals. Information sets to be prepared include safety data sheets (SDS), chemical safety reports (CSR), and chemical safety assessments (CSA). These are designed to guarantee adequate handling in the production chain, in transport and in use and to prevent the substances from being released to and distributed within the environment. Another important aim is to identify the most harmful chemicals and to set incentives to substitute them with safer alternatives. On one hand, REACH will have substantial impact on the basic understanding of the evaluation of chemicals. However, the toxicological sciences can also substantially influence the workability of REACH that supports the transformation of data to the information required to understand and manage acceptable and non acceptable risks in the use of industrial chemicals. The REACH regulation has been laid down in the main document and 17 Annexes of more than 849 pages. Even bigger technical guidance documents will follow and will inform about the rules for

  8. Quasi-chemical theory with a soft cutoff

    Energy Technology Data Exchange (ETDEWEB)

    Chempath, Shaji [Los Alamos National Laboratory; Pratt, Lawrence R [TULANE UNIV; Paulaitis, Michael E [OHIO STATE UNIV

    2008-01-01

    In view of the wide success of molecular quasichemical theory of liquids, this paper develops the soft-cutoff version of that theory. This development allows molecular dynamics simulations to be used for the calculation of solvation free energy, whereas the hard-cutoff version of the theory needs Monte Carlo simulations. This development also shows how fluids composed of molecules with smooth repulsive interactions can be treated analogously to the molecular-field theory of the hard-sphere fluid. In the treatment of liquid water, quasichemical theory with soft-cutoff conditioning does not change the fundamental convergence characteristics of the theory using hard-cutoff conditioning. In fact, hard cutoffs are found here to work better than softer ones in that case.

  9. Impact origin of the Sudbury structure: Evolution of a theory

    Science.gov (United States)

    Lowman, Paul D., Jr.

    1992-01-01

    This paper reviews the origin, development, and present status of the widely accepted theory, proposed by Robert S. Dietz in 1962, that the Sudbury structure was formed by meteoritic or asteroidal impact. The impact theory for the origin of the Sudbury structure seems supported by a nearly conclusive body of evidence. However, even assuming an impact origin to be correct, at least three major questions require further study: (1) the original size and shape of the crater, before tectonic deformation and erosion; (2) the source of the melt now forming the Sudbury Igneous Complex; and (3) the degree, if any, to which the Ni-Cu-platinum group elements are meteoritic. The history of the impact theory illustrates several under-appreciated aspects of scientific research: (1) the importance of cross-fertilization between space research and terrestrial geology; (2) the role of the outsider in stimulating thinking by insiders; (3) the value of small science, at least in the initial stages of an investigation, Dietz's first field work having been at his own expense; and (4) the value of analogies (here, between the Sudbury Igneous Complex and the maria), which although incorrect in major aspects, may trigger research on totally new lines. Finally, the Sudbury story illustrates the totally unpredictable and, by implication, unplannable nature of basic research, in that insight to the origin of the world's then-greatest Ni deposit came from the study of tektites and the Moon.

  10. Thermodynamic Branch in the Chemical System Response to External Impact

    CERN Document Server

    Zilbergleyt, B

    2012-01-01

    The paper gives an account of a detailed investigation of the thermodynamic branch as a path of the chemical system deviation from its isolated thermodynamic equilibrium under an external impact. For a combination of direct and reverse reactions in the same chemical system, full thermodynamic branch is presented by an S-shaped curve, whose ends asymptotically achieve appropriate initial states, which, in turn, are logistic ends of the opposite reactions. The slope tangents of the steepest parts of the curves, the areas of the maximum rate of the shift growth vs. the external thermodynamic force, occurred to be directly proportional to the force and, simultaneously, linearly proportional to the thermodynamic equivalent of chemical reaction, which is the ratio between the amount in moles of any reaction participant, transformed in an isolated system, along the reaction way from its initial state to thermodynamic equilibrium, to its stoichiometric coefficient. The found linearity is valid for arbitrary combinati...

  11. The Impact of Modeling Assumptions in Galactic Chemical Evolution Models

    CERN Document Server

    Côté, Benoit; Ritter, Christian; Herwig, Falk; Venn, Kim A

    2016-01-01

    We use the OMEGA galactic chemical evolution code to investigate how the assumptions used for the treatment of galactic inflows and outflows impact numerical predictions. The goal is to determine how our capacity to reproduce the chemical evolution trends of a galaxy is affected by the choice of implementation used to include those physical processes. In pursuit of this goal, we experiment with three different prescriptions for galactic inflows and outflows and use OMEGA within a Markov Chain Monte Carlo code to recover the set of input parameters that best reproduces the chemical evolution of nine elements in the dwarf spheroidal galaxy Sculptor. Despite their different degrees of intended physical realism, we found that all three prescriptions can reproduce in an almost identical way the stellar abundance trends observed in Sculptor. While the three models have the same capacity to fit the data, the best values recovered for the parameters controlling the number of Type Ia supernovae and the strength of gal...

  12. Managing the impacts of endocrine disrupting chemicals in wastewater-impacted streams

    Science.gov (United States)

    Journey, Celeste A.; Bradley, Paul M.; Kolpin, Dana W.; Bradley, Paul M.

    2013-01-01

    A revolution in analytical instrumentation circa 1920 greatly improved the ability to characterize chemical substances [1]. This analytical foundation resulted in an unprecedented explosion in the design and production of synthetic chemicals during and post-World War II. What is now often referred to as the 2nd Chemical Revolution has provided substantial societal benefits; with modern chemical design and manufacturing supporting dramatic advances in medicine, increased food production, and expanding gross domestic products at the national and global scales as well as improved health, longevity, and lifestyle convenience at the individual scale [1, 2]. Presently, the chemical industry is the largest manufacturing sector in the United States (U.S.) and the second largest in Europe and Japan, representing approximately 5% of the Gross Domestic Product (GDP) in each of these countries [2]. At the turn of the 21st century, the chemical industry was estimated to be worth more than $1.6 trillion and to employ over 10 million people, globally [2]. During the first half of the 20th century, the chemical sector expanded rapidly, the chemical industry enjoyed a generally positive status in society, and chemicals were widely appreciated as fundamental to individual and societal quality of life. Starting in the 1960s, however, the environmental costs associated with the chemical industry increasingly became the focus, due in part to the impact of books like “Silent Spring” [3] and “Our Stolen Future” [4] and to a number of highly publicized environmental disasters. Galvanizing chemical industry disasters included the 1976 dioxin leak north of Milan, Italy, the Love Canal evacuations in Niagara, New York beginning in 1978, and the Union Carbide leak in Bhopal, India in 1984 [2]. Understanding the environmental impact of synthetic compounds is essential to any informed assessment of net societal benefit, for the simple reason that any chemical substance that is in

  13. A semiclassical non-adiabatic theory for elementary chemical reactions

    CERN Document Server

    Aubry, Serge

    2014-01-01

    Electron Transfer (ET) reactions are modeled by the dynamics of a quantum two-level system (representing the electronic state) coupled to a thermalized bath of classical harmonic oscillators (representing the nuclei degrees of freedom). Unlike for the standard Marcus theory, the complex amplitudes of the electronic state are chosen as reaction coordinates. Then, the dynamical equations at non vanishing temperature become those of an effective Hamiltonian submitted to damping terms and their associated Langevin random forces. The advantage of this new formalism is to extend the original theory by taking into account both ionic and covalent interactions. The standard theory is recovered only when covalent interactions are neglected. Increasing these covalent interactions from zero, the energy barrier predicted by the standard theory first depresses, next vanish (or almost vanish) and for stronger covalent interactions, covalent bond formation takes place of ET. In biochemistry, the standard Marcus theory often ...

  14. Theory of the Kinetics of Chemical Potentials in Heterogeneous Catalysis

    OpenAIRE

    Cheng, Jun; Hu, P

    2011-01-01

    Simple and powerful: The reaction kinetics at surfaces of heterogeneous catalysts is reformulated in terms of the involved chemical potentials. Based on this formulism, an approach of searching for good catalysts is proposed without recourse to extensive calculations of reaction barriers and detailed kinetic analyses. (see picture; R=reactant, I=surface intermediate, P=product, and =standard chemical potential).

  15. Significance of vapor phase chemical reactions on CVD rates predicted by chemically frozen and local thermochemical equilibrium boundary layer theories

    Science.gov (United States)

    Gokoglu, Suleyman A.

    1988-01-01

    This paper investigates the role played by vapor-phase chemical reactions on CVD rates by comparing the results of two extreme theories developed to predict CVD mass transport rates in the absence of interfacial kinetic barrier: one based on chemically frozen boundary layer and the other based on local thermochemical equilibrium. Both theories consider laminar convective-diffusion boundary layers at high Reynolds numbers and include thermal (Soret) diffusion and variable property effects. As an example, Na2SO4 deposition was studied. It was found that gas phase reactions have no important role on Na2SO4 deposition rates and on the predictions of the theories. The implications of the predictions of the two theories to other CVD systems are discussed.

  16. Chemical Principles Revisited: Updating the Atomic Theory in General Chemistry.

    Science.gov (United States)

    Whitman, Mark

    1984-01-01

    Presents a descriptive overview of recent achievements in atomic structure to provide instructors with the background necessary to enhance their classroom presentations. Topics considered include hadrons, quarks, leptons, forces, and the unified fields theory. (JN)

  17. Stochastic chemical kinetics theory and (mostly) systems biological applications

    CERN Document Server

    Érdi, Péter

    2014-01-01

    This volume reviews the theory and simulation methods of stochastic kinetics by integrating historical and recent perspectives, presents applications, mostly in the context of systems biology and also in combustion theory. In recent years, due to the development in experimental techniques, such as optical imaging, single cell analysis, and fluorescence spectroscopy, biochemical kinetic data inside single living cells have increasingly been available. The emergence of systems biology brought renaissance in the application of stochastic kinetic methods.

  18. "Human Health Impact Characterization of Toxic Chemicals for Sustainable Design and Manufacturing

    OpenAIRE

    Yuan, Chris; Dornfeld, David

    2009-01-01

    A schematic method to characterize the human health impact of toxic chemicals is presented. This schematic method uses a streamlined three-tiered hierarchy process which includes intake, toxicity and persistence of a chemical release for its impact characterization. The human health impact of a chemical is represented by its position in a two-dimensional characterization plot, which enables the benchmarking of chemicals to be easily made by comparing the relative positions of the chemicals in...

  19. Explosive Containment Chamber Vulnerability to Chemical Munition Fragment Impact

    Energy Technology Data Exchange (ETDEWEB)

    Benham, R.A.; Fischer, S.H.; Kipp, M.E.; Martinez, R.R.

    1999-02-01

    Scenarios in which the explosive burster charge in a chemical munition accidentally detonates inside demilitarization containment chambers are analyzed. The vulnerability of an inner Auxiliary Pressure Vessel and the primary Explosive Containment Chamber to impact by fragments from the largest explosive charge expected to be placed in these chambers (M426, 8 inch, chemical, 7 lbs Comp B) is evaluated. Numerical (CTH) and empirical (ConWep) codes are used to characterize the munition fragments, and assess the consequences of their impact and penetration on the walls of these vessels. Both pristine and corroded configurations of the munition have been considered, with and without liquid agent fill. When the munition burster charge detonates, munition case fragments impact and perforate the Auxiliary Pressure Vessel wall, resulting in extensive breakup of this inner chamber and the formation of additional fragments. These residual munition case and Auxiliary Pressure Vessel fragments have sufficient mass and velocity to crater the Explosive Containment Chamber inner wall layer, with accompanying localized permanent deformation (bulging) of both the inner and outer chamber walls. The integrity of the Explosive Containment Chamber was retained under all of the APV / munition configurations considered in this study, with no evidence that primary (munition) or secondary (munition and Auxiliary Pressure Vessel) fragments will perforate the inner chamber wall. Limited analyses of munition detonation without the Auxiliary Pressure Vessel present indicate that some munition span fragments could form under those conditions that have sufficient mass and velocity to perforate the inner wall of the Explosive Containment Chamber.

  20. Chemical Reaction Rates from Ring Polymer Molecular Dynamics: Theory and Practical Applications

    CERN Document Server

    Suleimanov, Yury V; Guo, Hua

    2016-01-01

    This Feature Article presents an overview of the current status of Ring Polymer Molecular Dynamics (RPMD) rate theory. We first analyze theory and its connection to quantum transition state theory. We then focus on its practical application to prototypical chemical reactions in the gas phase, which demonstrate how accurate and reliable RPMD is for calculating thermal chemical reaction rates in multifarious cases. This review serves as an important checkpoint in RPMD rate theory development, which shows that RPMD is shifting from being just one of recent novel ideas to a well-established and validated alternative to conventional techniques for calculating thermal chemical rates. We also hope it will motivate further applications of RPMD to various chemical reactions.

  1. Empiricism or self-consistent theory in chemical kinetics?

    International Nuclear Information System (INIS)

    To give theoretical background for mechanochemical kinetics, we need first of all to find a possibility to predict the kinetic parameters for real chemical processes by determining rate constants and reaction orders without developing strictly specialized and, to a great extent, artificial models, i.e. to derive the kinetic law of mass action from 'first principles'. However, the kinetic law of mass action has had only an empirical basis from the first experiments of Gulberg and Waage until now, in contrast to the classical law of mass action for chemical equilibrium rigorously derived in chemical thermodynamics from equilibrium condition. Nevertheless, in this paper, an attempt to derive the kinetic law of mass action from 'first principles' is made in macroscopic formulation. It has turned out to be possible owing to the methods of thermodynamics of irreversible processes that were unknown in Gulberg and Waage's time

  2. The Lattice Compatibility Theory: Supports from the Generalized Simha-Somcynsky Chemical Physics-Related Theory

    OpenAIRE

    Boubaker, K; Colantoni, A; Petkova, P.

    2013-01-01

    The earliest models used in the study of lattice structures are mean field theories, which do not contain structural dependence. The Lattice Compatibility Theory (LCT) proposes here a novel framework where the measure of the disorder is based on Urbach tailing features and lattice matching features between the host matrix and doping agent intrinsic structures. This study has been implemented on a particular compound (BTO:Co) and refers to the Simha-Somcynsky (SS) theory, a mean field theory w...

  3. Supporting Alternative Strategies for Learning Chemical Applications of Group Theory

    Science.gov (United States)

    Southam, Daniel C.; Lewis, Jennifer E.

    2013-01-01

    A group theory course for chemists was taught entirely with process oriented guided inquiry learning (POGIL) to facilitate alternative strategies for learning. Students completed a test of one aspect of visuospatial aptitude to determine their individual approaches to solving spatial tasks, and were sorted into groups for analysis on the basis of…

  4. Fluctuation theory of solutions applications in chemistry, chemical engineering, and biophysics

    CERN Document Server

    Smith, Paul E

    2013-01-01

    There are essentially two theories of solutions that can be considered exact: the McMillan-Mayer theory and Fluctuation Solution Theory (FST). The first is mostly limited to solutes at low concentrations, while FST has no such issue. It is an exact theory that can be applied to any stable solution regardless of the number of components and their concentrations, and the types of molecules and their sizes. Fluctuation Theory of Solutions: Applications in Chemistry, Chemical Engineering, and Biophysics outlines the general concepts and theoretical basis of FST and provides a range of applications

  5. Theory for Diffusion-Limited Oscillating Chemical Reactions

    OpenAIRE

    Bussemaker, H. J.; Brito López, Ricardo

    1996-01-01

    A kinetic description of lattice-gas automaton models for reaction-diffusion systems is presented. It provides corrections to the mean-field rate equations in the diffusion-limited regime. When applied to the two-species Maginu model, the theory gives an excellent quantitative prediction of the effect of slow diffusion on the periodic oscillations of the average concentrations in a spatially homogeneous state.

  6. Theory for Diffusion-Limited Oscillating Chemical Reactions

    CERN Document Server

    Bussemaker, H J

    1997-01-01

    A kinetic description of lattice-gas automaton models for reaction-diffusion systems is presented. It provides corrections to the mean-field rate equations in the diffusion-limited regime. When applied to the two-species Maginu model, the theory gives an excellent quantitative prediction of the effect of slow diffusion on the periodic oscillations of the average concentrations in a spatially homogeneous state.

  7. A lattice theory for low energy fermions at finite chemical potential

    CERN Document Server

    Chen, J W; Chen, Jiunn-Wei; Kaplan, David B.

    2003-01-01

    We construct a lattice theory describing a system of interacting nonrelativistic spin s=1/2 fermions at finite chemical potential, which does not suffer from a sign problem. The theory is applicable whenever the interparticle separation is large compared to the range of the two-body potential. The theory could have applications to realistic atomic Bose-Einstein condensates and dilute neutron gases.

  8. Chemical deuteration in neutron scattering: Demand, supply and impact

    International Nuclear Information System (INIS)

    Molecular deuteration significantly increases the options in structure function investigations using Neutron Scatteringand diffraction techniques. There have been limited global initiatives in the field of molecular deuteration where the majority of these programs focus on biological deuteration of proteins and lipids, while more complex deuterated small molecules haven’t been widely available to the neutron community. This has limited the experiments that can be performed, and formed a bottle-neck for advancing the applications of neutron scattering. In this paper we will discuss the recent advancements and the impact of deuteration on the research outcomes achieved by using deuterated molecules produced by the chemical deuteration laboratories at the National Deuteration Facility in the Bragg Institute, ANSTO. Recent high-impact case studies will be presented which reveal the exciting and diverse characterisation studies which are now available for the neutron community. We describe here the synthesis and application of deuterated organic molecules used to investigate complex nanoscale systems in the fields of molecular electronics, structural biology, and biotechnology. The chemical deuteration of surfactants, sugars, heterocyclic and aromatic compounds has made possible a wide range of investigations. This includes the study of (i) the localisation of sugars in lipid membranes using neutron diffraction to give insights into cryoprotective mechanisms, (ii) the pH-responsiveness of the assembly of lipid digestion products in biologically relevant systems, and (iii) the structure and host-guest properties of metal-organic frameworks (MOFs) using neutron diffraction.

  9. Kinetic Theory of Positron-Impact Ionization in Gases

    CERN Document Server

    Boyle, G J; Cocks, D G; Dujko, S; White, R D

    2016-01-01

    A kinetic theory model is developed for positron-impact ionization (PII) with neutral, rarefied gases. Particular attention is given to the sharing of available energy between the post-ionization constituents. A simple model for the energy-partition function that qualitatively captures the physics of high-energy and near-threshold ionization is developed for PII, with free parameters that can be used to fit the model to experimental data. By applying the model to the measurements of Kover and Laricchia [1] for positrons in H2, the role of energy-partitioning in PII for positron thermalisation is studied. Although the overall thermalisation time is found to be relatively insensitive to the energy-partitioning, the mean energy profiles at certain times can differ by more than an order of magnitude for the various treatments of energy-partitioning. This can significantly impact the number and energy distribution of secondary electrons.

  10. Dynamics of prebiotic RNA reproduction illuminated by chemical game theory.

    Science.gov (United States)

    Yeates, Jessica A M; Hilbe, Christian; Zwick, Martin; Nowak, Martin A; Lehman, Niles

    2016-05-01

    Many origins-of-life scenarios depict a situation in which there are common and potentially scarce resources needed by molecules that compete for survival and reproduction. The dynamics of RNA assembly in a complex mixture of sequences is a frequency-dependent process and mimics such scenarios. By synthesizing Azoarcus ribozyme genotypes that differ in their single-nucleotide interactions with other genotypes, we can create molecules that interact among each other to reproduce. Pairwise interplays between RNAs involve both cooperation and selfishness, quantifiable in a 2 × 2 payoff matrix. We show that a simple model of differential equations based on chemical kinetics accurately predicts the outcomes of these molecular competitions using simple rate inputs into these matrices. In some cases, we find that mixtures of different RNAs reproduce much better than each RNA type alone, reflecting a molecular form of reciprocal cooperation. We also demonstrate that three RNA genotypes can stably coexist in a rock-paper-scissors analog. Our experiments suggest a new type of evolutionary game dynamics, called prelife game dynamics or chemical game dynamics. These operate without template-directed replication, illustrating how small networks of RNAs could have developed and evolved in an RNA world.

  11. Dynamics of prebiotic RNA reproduction illuminated by chemical game theory.

    Science.gov (United States)

    Yeates, Jessica A M; Hilbe, Christian; Zwick, Martin; Nowak, Martin A; Lehman, Niles

    2016-05-01

    Many origins-of-life scenarios depict a situation in which there are common and potentially scarce resources needed by molecules that compete for survival and reproduction. The dynamics of RNA assembly in a complex mixture of sequences is a frequency-dependent process and mimics such scenarios. By synthesizing Azoarcus ribozyme genotypes that differ in their single-nucleotide interactions with other genotypes, we can create molecules that interact among each other to reproduce. Pairwise interplays between RNAs involve both cooperation and selfishness, quantifiable in a 2 × 2 payoff matrix. We show that a simple model of differential equations based on chemical kinetics accurately predicts the outcomes of these molecular competitions using simple rate inputs into these matrices. In some cases, we find that mixtures of different RNAs reproduce much better than each RNA type alone, reflecting a molecular form of reciprocal cooperation. We also demonstrate that three RNA genotypes can stably coexist in a rock-paper-scissors analog. Our experiments suggest a new type of evolutionary game dynamics, called prelife game dynamics or chemical game dynamics. These operate without template-directed replication, illustrating how small networks of RNAs could have developed and evolved in an RNA world. PMID:27091972

  12. Chemical dehumidification by liquid desiccants: theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M.; Gasparella, A.; Longo, G.A. [Universita di Padova, Dip. di Tecnica e Gestione dei Sistemi Industriale, Vicenza (Italy)

    1999-06-01

    Chemical dehumidification of air by a liquid desiccant in a packed tower has been investigated both theoretically and experimentally for air conditioning and industrial applications. A computer model of a packed tower, able to determine heat and mass transfer between air and desiccant, has been developed and a parametrical study was carried out considering the solutions H{sub 2}O/LiBr and H{sub 2}O/CaCl{sub 2} to determine the optimum operative conditions. An experimental apparatus including a packed tower and a desiccant regenerator has been described together with experimental results: a set of 70 experimental runs with H{sub 2}O/LiBr. Data have been reported and compared against the results of the computer code simulations. (Author)

  13. Chemical dehumidification by liquid desiccants. Theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M.; Gasparella, A. [Instituto di Ingegneria Gestionale dell`Universita di Padova, Padova (Italy); Longo, G.A. [Instituto di Fisica Tecnica dell`Universita di Padova, Padova (Italy)

    1997-06-01

    Chemical dehumidification of air by a liquid desiccant in packed tower has been investigated both theoretically and experimentally for air conditioning and industrial applications. A computer model of a packed tower, able to determine the heat and mass transfer between air and desiccant, has been developed and a parametrical study was carried out considering the solutions H2O/LiBr and H2O/CaCl2 to determine the optimum operative conditions. An experimental apparatus including a packed tower and a desiccant regenerator has been describe together with experimental results: a set of 70 experimental runs with H2O/LiBr. Dat have been reported and compared against the results of the computer code simulations. 16 refs.

  14. Quasi-chemical Theory and the Statistical Thermodynamics of the Hard Sphere Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, L. R.; Laviolette, Randall Alexander; Gomez, M. A.; Gentile, M.

    2001-09-01

    We develop a quasi-chemical theory for the study of packing thermodynamics in dense liquids. The situation of hard-core interactions is addressed by considering the binding of solvent molecules to a precisely defined cavity in order to assess the probability that the cavity is entirely evacuated. The primitive quasi-chemical approximation corresponds to an extension of the Poisson distribution used as a default model in an information theory approach. This primitive quasi-chemical theory is in good qualitative agreement with the observations for the hard-sphere fluid of occupancy distributions that are central to quasi-chemical theories but begins to be quantitatively erroneous for the equation of state in the dense liquid regime of d3 > 0.6. How the quasi-chemical approach can be iterated to treat correlation effects is addressed. Consideration of neglected correlation effects leads to a simple model for the form of those contributions neglected by the primitive quasi-chemical approximation. These considerations, supported by simulation observations, identify a "break away" phenomena that requires special thermodynamic consideration for the zero (0) occupancy case as distinct from the rest of the distribution. An empirical treatment leads to a one-parameter model occupancy distribution that accurately fits the hard-sphere equation of state and observed distributions.

  15. Quasi-chemical Theory for the Statistical Thermodynamics of the Hard Sphere Fluid

    CERN Document Server

    Pratt, L R; Gómez, M A; Gentile, M E; Pratt, Lawrence R.; Violette, Randall A. La; Gomez, Maria A.; Gentile, Mary E.

    2001-01-01

    We develop a quasi-chemical theory for the study of packing thermodynamics in dense liquids. The situation of hard-core interactions is addressed by considering the binding of solvent molecules to a precisely defined `cavity' in order to assess the probability that the `cavity' is entirely evacuated. The primitive quasi-chemical approximation corresponds to a extension of the Poisson distribution used as a default model in an information theory approach. This primitive quasi-chemical theory is in good qualitative agreement with the observations for the hard sphere fluid of occupancy distributions that are central to quasi-chemical theories but begins to be quantitatively erroneous for the equation of state in the dense liquid regime of $\\rho d^3>$0.6. How the quasi-chemical approach can be iterated to treat correlation effects is addressed. Consideration of neglected correlation effects leads to a simple model for the form of those contributions neglected by the primitive quasi-chemical approximation. These c...

  16. Molecular cluster theory of chemical bonding in actinide oxide

    International Nuclear Information System (INIS)

    The electronic structure of actinide monoxides AcO and dioxides AcO2, where Ac = Th, U, Np, Pu, Am, Cm and Bk has been studied by molecular cluster methods based on the first-principles one-electron local density theory. Molecular orbitals for nearest neighbor clusters AcO10-6 and AcO12-8 representative of monoxide and dioxide lattices were obtained using non-relativistic spin-restricted and spin-polarized Hartree-Fock-Slater models for the entire series. Fully relativistic Dirac-Slater calculations were performed for ThO, UO and NpO in order to explore magnitude of spin-orbit splittings and level shifts in valence structure. Self-consistent iterations were carried out for NpO, in which the NpO6 cluster was embedded in the molecular field of the solid. Finally, a ''moment polarized'' model which combines both spin-polarization and relativistic effects in a consistent fashion was applied to the NpO system. Covalent mixing of oxygen 2p and Ac 5f orbitals was found to increase rapidly across the actinide series; metal s,p,d covalency was found to be nearly constant. Mulliken atomic population analysis of cluster eigenvectors shows that free-ion crystal field models are unreliable, except for the light actinides. X-ray photoelectron line shapes have been calculated and are found to compare rather well with experimental data on the dioxides

  17. 75 FR 69630 - Impact of Implementation of the Chemical Weapons Convention on Commercial Activities Involving...

    Science.gov (United States)

    2010-11-15

    ... Bureau of Industry and Security Impact of Implementation of the Chemical Weapons Convention on Commercial... implementation of the Chemical Weapons Convention (CWC), through the Chemical Weapons Convention Implementation Act (CWCIA) and the Chemical Weapons Convention Regulations (CWCR), has had on commercial...

  18. 77 FR 75145 - Impact of the Implementation of the Chemical Weapons Convention (CWC) on Commercial Activities...

    Science.gov (United States)

    2012-12-19

    ... Bureau of Industry and Security Impact of the Implementation of the Chemical Weapons Convention (CWC) on... implementation of the Chemical Weapons Convention (CWC), through the Chemical Weapons Convention Implementation Act (CWCIA) and the Chemical Weapons Convention Regulations (CWCR), has had on commercial...

  19. A new theory of chemical method to prevent spontaneous combustion of coal

    Institute of Scientific and Technical Information of China (English)

    LU Wei

    2009-01-01

    In order to prevent spontaneous combustion of coal from the source, based on the study on the mechanism of spontaneous combustion of coal, especially the process of coal to self-ignite and different activate structures have different activation for oxidization, the new theory and mechanism with chemical inhibition that can change the tendency of spontaneous combustion of coal and let the activate structures deactivate were brought forward. Therefore, coal was not self-ignited under a certain temperature when being chemically inhibited.

  20. Variation Theory: A Theory of Learning and a Useful Theoretical Framework for Chemical Education Research

    Science.gov (United States)

    Bussey, Thomas J.; Orgill, MaryKay; Crippen, Kent J.

    2013-01-01

    Instructors are constantly baffled by the fact that two students who are sitting in the same class, who have access to the same materials, can come to understand a particular chemistry concept differently. Variation theory offers a theoretical framework from which to explore possible variations in experience and the resulting differences in…

  1. Nobel Prize 1992: Rudolph A. Marcus: theory of electron transfer reactions in chemical systems

    International Nuclear Information System (INIS)

    A review of the theory developed by Rudolph A. Marcus is presented, who for his rating to the theory of electron transfer in chemical systems was awarded the Nobel Prize in Chemistry in 1992. Marcus theory has constituted not only a good extension of the use of a spectroscopic principle, but also has provided an energy balance and the application of energy conservation for electron transfer reactions. A better understanding of the reaction coordinate is exposed in terms energetic and establishing the principles that govern the transfer of electrons, protons and some labile small molecular groups as studied at present. Also, the postulates and equations described have established predictive models of reaction time, very useful for industrial environments, biological, metabolic, and others that involve redox processes. Marcus theory itself has also constituted a large contribution to the theory of complex transition

  2. Nuclear radiation as a probe of chemical bonding: the current interplay between theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Newton, M D

    1978-01-01

    After a survey of appropriate theoretical formalisms, recent confrontations of theory and experiment in the areas of neutron scattering, Moessbauer spectroscopy, and positron chemistry are discussed, with major emphasis on the degree to which simple concepts of chemical bonding can be refined by complementary use of the above experimental probes and the powerful techniques of computational quantum chemistry.

  3. Thermodynamics of large N gauge theories with chemical potentials in a 1/ D expansion

    Science.gov (United States)

    Morita, Takeshi

    2010-08-01

    In order to understand thermodynamical properties of N D-branes with chemical potentials associated with R-symmetry charges, we study a one dimensional large N gauge theory (bosonic BFSS type model) as a first step. This model is obtained through a dimensional reduction of a 1 + D dimensional SU( N) Yang-Mills theory and we use a 1 /D expansion to investigate the phase structure. We find three phases in the μ - T plane. We also show that all the adjoint scalars condense at large D and obtain a mass dynamically. This dynamical mass protects our model from the usual perturbative instability of massless scalars in a non-zero chemical potential. We find that the system is at least meta-stable for arbitrary large values of the chemical potentials in D → ∞ limit. We also explore the existence of similar condensation in higher dimensional gauge theories in a high temperature limit. In 2 and 3 dimensions, the condensation always happens as in one dimensional case. On the other hand, if the dimension is higher than 4, there is a critical chemical potential and the condensation happens only if the chemical potentials are below it.

  4. Power optimization of chemically driven heat engine based on first and second order reaction kinetic theory and probability theory

    Science.gov (United States)

    Zhang, Lei; Chen, Lingen; Sun, Fengrui

    2016-03-01

    The finite-time thermodynamic method based on probability analysis can more accurately describe various performance parameters of thermodynamic systems. Based on the relation between optimal efficiency and power output of a generalized Carnot heat engine with a finite high-temperature heat reservoir (heat source) and an infinite low-temperature heat reservoir (heat sink) and with the only irreversibility of heat transfer, this paper studies the problem of power optimization of chemically driven heat engine based on first and second order reaction kinetic theory, puts forward a model of the coupling heat engine which can be run periodically and obtains the effects of the finite-time thermodynamic characteristics of the coupling relation between chemical reaction and heat engine on the power optimization. The results show that the first order reaction kinetics model can use fuel more effectively, and can provide heat engine with higher temperature heat source to increase the power output of the heat engine. Moreover, the power fluctuation bounds of the chemically driven heat engine are obtained by using the probability analysis method. The results may provide some guidelines for the character analysis and power optimization of the chemically driven heat engines.

  5. Epigenome: A Biomarker or Screening Tool to Evaluate Health Impact of Cumulative Exposure to Chemical and Non-Chemical Stressors.

    Science.gov (United States)

    Olden, Kenneth; Lin, Yu-Sheng; Bussard, David

    2016-06-01

    Current risk assessment practices and toxicity information are hard to utilize for assessing the health impact of combined or cumulative exposure to multiple chemical and non-chemical stressors encountered in the "real world" environment. Non-chemical stressors such as heat, radiation, noise, humidity, bacterial and viral agents, and social factors, like stress related to violence and socioeconomic position generally cannot be currently incorporated into the risk assessment paradigm. The Science and Decisions report released by the National Research Council (NRC) in 2009 emphasized the need to characterize the effects of multiple stressors, both chemical and non-chemical exposures. One impediment to developing information relating such non-chemical stressors to health effects and incorporating them into cumulative assessment has been the lack of analytical tools to easily and quantitatively monitor the cumulative exposure to combined effects of stressors over the life course.

  6. Epigenome: A Biomarker or Screening Tool to Evaluate Health Impact of Cumulative Exposure to Chemical and Non-Chemical Stressors.

    Science.gov (United States)

    Olden, Kenneth; Lin, Yu-Sheng; Bussard, David

    2016-06-01

    Current risk assessment practices and toxicity information are hard to utilize for assessing the health impact of combined or cumulative exposure to multiple chemical and non-chemical stressors encountered in the "real world" environment. Non-chemical stressors such as heat, radiation, noise, humidity, bacterial and viral agents, and social factors, like stress related to violence and socioeconomic position generally cannot be currently incorporated into the risk assessment paradigm. The Science and Decisions report released by the National Research Council (NRC) in 2009 emphasized the need to characterize the effects of multiple stressors, both chemical and non-chemical exposures. One impediment to developing information relating such non-chemical stressors to health effects and incorporating them into cumulative assessment has been the lack of analytical tools to easily and quantitatively monitor the cumulative exposure to combined effects of stressors over the life course. PMID:27534725

  7. Tharsis Formation by Chemical Plume Due to Giant Impact Event

    Science.gov (United States)

    Fleck, J.; Weeraratne, D. S.; Olson, P.

    2014-12-01

    Tharsis formed early in the history of Mars, likely during the Noachian but later than the hemispheric crustal dichotomy that it partially overprints (Johnson and Phillips, 2005; Solomon et al., 2005; Wenzel et al., 2004). It has been suggested that the crustal dichotomy may have been formed by a giant impact (Andrews-Hanna et al., 2008; Marinova et al., 2008; Nimmo et al., 2008). Several models have been proposed to explain a localized orogeny, but predict multiple, evenly-spaced plumes or have instability growth and rise times which are longer than Tharsis formation. We use fluid dynamic experiments to model the differentiation process during Mars accretion using low viscosity glucose syrup solutions and an emulsion of liquid gallium for the metal-rich magma ocean and a high viscosity glucose syrup for the mantle. Our experiments demonstrate the formation of metal-silicate diapirs from metal emulsion drops that form a pond at the base of the magma ocean. The diapirs descend through the underlying mantle with trailing conduit of low viscosity silicate material. The silicate material is buoyant and eventually ascends back through the conduit. Remaining emulsion drops that do not adhere with the diapir fall through the conduit, forcing the buoyant molten silicate material to exit the conduit laterally and ascend along a new trajectory. The time elapsed between diapir formation and ascent of the chemical plume in experiments scales with the time between the formation of the crustal dichotomy on Mars and the formation of Tharsis. Our model offers an explanation for the rapid formation of Tharsis on the edge of the crustal dichotomy via a single large upwelling event followed by smaller upwellings producing and the late stages of effusive volcanism observed in the Tharsis region.

  8. Effective Polyakov loop models for QCD-like theories at finite chemical potential

    CERN Document Server

    Scior, Philipp

    2016-01-01

    We study genuine finite density effects in QCD-like theories with three-dimensional Polyakov-loop effective theories for heavy quarks. These are derived from the full QCD-like theories by combined strong-coupling and hopping expansions. In particular, we investigate the cold and dense regimes of phase diagrams where we expect to find Bose-Einstein-condensation of diquark baryons or a fermionic first-order liquid-gas transition, depending on the gauge group of the theory. In two-color QCD, for example, we observe evidence of a continuous zero-temperature transition to finite diquark density when the quark chemical potential $\\mu$ reaches half the diquark mass, i.e. without binding energy. In G$_2$-QCD we observe, in addition to this "Silver Blaze" onset of diquark density, a second transition in the density towards an exponential increase by roughly $3\\mu/T$ corresponding to a finite density of G$_2$-nucleons.

  9. Incorporating Health Impacts from Exposure to Chemicals in Food Packaging in LCA

    OpenAIRE

    Ernstoff, Alexi; Trier, Xenia; Jolliet, Oliver; Fantke, Peter

    2014-01-01

    Life cycle assessments (LCA) on the environmental and public health impacts of food and beverage packaging materials have found some advantages to plastic over glass. Entirely missing from these evaluations are the health impacts of possible chemical, e.g. endocrine dis-ruptor, exposure through migration of chemicals from the packaging into the food product. We build a framework based on a life cycle perspective to predict which chemicals may be in a package that are not intentionally added i...

  10. COSMO-RSC: Second-Order Quasi-Chemical Theory Recovering Local Surface Correlation Effects.

    Science.gov (United States)

    Klamt, A

    2016-03-31

    The conductor-like screening model for realistic solvation (COSMO-RS) was introduced 20 years ago and meanwhile has become an important tool for the prediction of fluid phase equilibrium properties. Starting from quantum chemical information about the surface polarity of solutes and solvents, it solves the statistical thermodynamics of molecules in liquid phases by the very efficient approximation of independently pairwise interacting surfaces, which meanwhile was shown to be equivalent to Guggenheim's quasi-chemical theory. One of the basic limitations of COSMO-RS, as of any quasi-chemical model, is the neglect of neighbor information, i.e., of local correlations of surface types on the molecular surface. In this paper we present the completely novel concept of using the first-order COSMO-RS contact probabilities for the construction of local surface correlation functions. These are fed as an entropic correction for the pair interactions into a second COSMO-RS self-consistency loop, which yields new contact probabilities, enthalpies, free energies and activity coefficients recovering much of the originally lost neighbor effects. By a novel analytic correction for concentration dependent interactions, the resulting activity coefficients remain exactly Gibbs-Duhem consistent. The theory is demonstrated on the example of a lattice Monte Carlo fluid of dimerizing pseudomolecules. In this showcase the strong deviations of the lattice Monte Carlo fluid from quasi-chemical theory are almost perfectly reproduced by COSMO-RSC.

  11. Sustainable Material Selection of Toxic Chemicals in Design and Manufacturing From Human Health Impact Perspective

    OpenAIRE

    Yuan, Chris; Dornfeld, David

    2009-01-01

    Toxic chemicals used in product design and manufacturing are grave concerns due to their significant impact on human health. Sustainable material selections are needed by industry to reduce the overall impact of toxic chemicals in both design and manufacturing. In this paper, we integrate the human health impact assessment into standard material selection process for developing a sustainable material selection metric for decision support in design and manufacturing. A schematic method is pres...

  12. A density functional theory-based chemical potential equalisation approach to molecular polarizability

    Indian Academy of Sciences (India)

    Amita Wadehra; Swapan K Ghosh

    2005-09-01

    The electron density changes in molecular systems in the presence of external electric fields are modeled for simplicity in terms of the induced charges and dipole moments at the individual atomic sites. A chemical potential equalisation scheme is proposed for the calculation of these quantities and hence the dipole polarizability within the framework of density functional theory based linear response theory. The resulting polarizability is expressed in terms of the contributions from individual atoms in the molecule. A few illustrative numerical calculations are shown to predict the molecular polarizabilities in good agreement with available results. The usefulness of the approach to the calculation of intermolecular interaction needed for computer simulation is highlighted.

  13. Concept of chemical bond and aromaticity based on quantum information theory

    CERN Document Server

    Szilvási, T; Legeza, Ö

    2015-01-01

    Quantum information theory (QIT) emerged in physics as standard technique to extract relevant information from quantum systems. It has already contributed to the development of novel fields like quantum computing, quantum cryptography, and quantum complexity. This arises the question what information is stored according to QIT in molecules which are inherently quantum systems as well. Rigorous analysis of the central quantities of QIT on systematic series of molecules offered the introduction of the concept of chemical bond and aromaticity directly from physical principles and notions. We identify covalent bond, donor-acceptor dative bond, multiple bond, charge-shift bond, and aromaticity indicating unified picture of fundamental chemical models from ab initio.

  14. Assessment of chemical emissions in life cycle impact assessment - focus on low substance data availability and

    DEFF Research Database (Denmark)

    Larsen, Henrik Fred

    2004-01-01

    a low data demand ecotoxicity effect indicator to be used together with a fate indicator, when estimating the potential impact of chemical emissions. The results of the case study document that for LCAs on printed matter, the inclusion of chemical-related impact categories can be decisive...... for the outcome, and it shows that chemical-related impact categories are poorly or not at all included in previous studies. The share for the total environmental impact of for example the printing process in the case study is reduced from 41% to 10%, if the chemical-related impact categories are excluded. So...... associated selection methods EDIP-selection (revised version) and Priofactor. A statistical test of correlation in ranking between EDIP97, Priofactor, CPM and EURAM shows significant correlation in all cases. The main reason for this result is that a common perception of what makes a substance...

  15. Self-theories and Alternative Variables: Impacts on IQ and Intelligence

    OpenAIRE

    Taylor, Kari D

    2013-01-01

    Dweck (1999) proposes that self-theories – a person’s beliefs about themselves - lead to differences in motivation and achievement. Although self-theories are found to be influential in children, this study examines their effects in a university, student population. Through the use of online questionnaires and replication and expansion of two previous studies, this investigation looked at the impact of self-theories on achievement; the effect inducing self-theories had on attributions and r...

  16. Thermodynamics of Large N Gauge Theories with Chemical Potentials in a 1/D Expansion

    CERN Document Server

    Morita, Takeshi

    2010-01-01

    In order to understand thermodynamical properties of N D-branes with chemical potentials associated with R-symmetry charges, we study a one dimensional large N gauge theory (bosonic BFSS type model) as a first step. This model is obtained through a dimensional reduction of a 1+D dimensional SU(N) Yang-Mills theory and we use a 1/D expansion to investigate the phase structure. We find three phases in the \\mu-T plane. We also show that all the adjoint scalars condense at large D and obtain a mass dynamically. This dynamical mass protects our model from the usual perturbative instability of massless scalars in a non-zero chemical potential. We find that the system is at least meta-stable for arbitrary large values of the chemical potentials in D \\to \\infty limit. We also explore the existence of similar condensation in higher dimensional gauge theories in a high temperature limit. In 2 and 3 dimensions, the condensation always happens as in one dimensional case. On the other hand, if the dimension is higher than...

  17. NATO Advanced Research Workshop on The Theory of Chemical Reaction Dynamics

    CERN Document Server

    1986-01-01

    The calculation of cross sections and rate constants for chemical reactions in the gas phase has long been a major problem in theoretical chemistry. The need for reliable and applicable theories in this field is evident when one considers the significant recent advances that have been made in developing experimental techniques, such as lasers and molecular beams, to probe the microscopic details of chemical reactions. For example, it is now becoming possible to measure cross sections for chemical reactions state selected in the vibrational­ rotational states of both reactants and products. Furthermore, in areas such as atmospheric, combustion and interstellar chemistry, there is an urgent need for reliable reaction rate constant data over a range of temperatures, and this information is often difficult to obtain in experiments. The classical trajectory method can be applied routinely to simple reactions, but this approach neglects important quantum mechanical effects such as tunnelling and resonances. For al...

  18. Incorporating Health Impacts from Exposure to Chemicals in Food Packaging in LCA

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Trier, Xenia; Jolliet, Oliver;

    2014-01-01

    Life cycle assessments (LCA) on the environmental and public health impacts of food and beverage packaging materials have found some advantages to plastic over glass. Entirely missing from these evaluations are the health impacts of possible chemical, e.g. endocrine dis-ruptor, exposure through...... migration of chemicals from the packaging into the food product. We build a framework based on a life cycle perspective to predict which chemicals may be in a package that are not intentionally added ingredients, and we apply this approach to the US EPA’s CPCAT database. In total we find 1,154 chemicals...... within the CPCAT database related to food-contact materials; out of these 107 are potential endocrine disruptors according to the TEDX list of endocrine disruptors. We also build a framework in an effort to begin harmonizing LCA to include health impacts of chemical exposure related to food packaging...

  19. Spectroscopic Observation of Chemical Interaction Between Impact-induced Vapor Clouds and the Ambient Atmosphere

    Science.gov (United States)

    Sugita, S.; Heineck, J. T.; Schultz, P. H.

    2000-01-01

    Chemical reactions within impact-induced vapor clouds were observed in laboratory experiments using a spectroscopic method. The results indicate that projectile-derived carbon-rich vapor reacts intensively with atmospheric nitrogen.

  20. Application of Chemically Accelerated Biotreatment to Reduce Risk in Oil-Impacted Soils

    Energy Technology Data Exchange (ETDEWEB)

    Paterek, J.R.; Bogan, W.W.; Sirivedhin; Tanita

    2003-03-06

    Research was conducted in six major focus areas: (1) Evaluation of the process using 6 test soils with full chemical and physical characteristics to determine controlling factors for biodegradation and chemical oxidation; (2) Determination of the sequestration time on chemical treatment suspectability; (3) Risk factors, i.e. toxicity after chemical and biological treatment; (4) Impact of chemical treatment (Fenton's Reagent) on the agents of biodegradation; (5) Description of a new genus and its type species that degrades hydrocarbons; and (6) Intermediates generate from Fenton's reagent treatment of various polynuclear aromatic hydrocarbons.

  1. Chemical Footprint Method for Improved Communication of Freshwater Ecotoxicity Impacts in the Context of Ecological Limits

    DEFF Research Database (Denmark)

    Bjørn, Anders; Diamond, Miriam; Birkved, Morten;

    2014-01-01

    The ecological footprint method has been successful in communicating environmental impacts of anthropogenic activities in the context of ecological limits. We introduce a chemical footprint method that expresses ecotoxicity impacts from anthropogenic chemical emissions as the dilution needed...... capacity was likely exceeded for most European countries and all landlocked metropolitan areas. The second case study indicated that peak application of pesticides alone was likely to exceed Denmark's freshwater dilution capacity in 1999-2011. The uncertainty assessment showed that better spatially...

  2. IM:PACT: Course Redesign Theory and Practice

    OpenAIRE

    Doan, Tomalee; Levesque-Bristol, Chantal; Attardo, Donalee

    2012-01-01

    Presented to Department of Athletics, Purdue University, West Lafayette, IN.. Examines active learning. collaborative learning and team-based approaches through multiple choice questions. Describes faculty involvement in student-centered learning and role of technology in IMPACT and innovative learning spaces.. Provides stats for course redesign through Instruction Matters Purdue Academic Course Transformation (IMPACT),

  3. Numerical modeling of chemical spills and assessment of their environmental impacts

    Science.gov (United States)

    Chemical spills in surface water bodies often occur in modern societies, which cause significant impacts on water quality, eco-environment and drinking water safety. In this paper, chemical spill contamination in water resources was studied using a depth-integrated computational model, CCHE2D, for p...

  4. The Impact of Cognitive Load Theory on Learning Astronomy

    Science.gov (United States)

    Foster, Thomas M.

    2010-01-01

    Every student is different, which is the challenge of astronomy education research (AER) and teaching astronomy. This difference also provides the greatest goal for education researchers - our GUT - we need to be able to quantify these differences and provide explanatory and predictive theories to curriculum developers and teachers. One educational theory that holds promise is Cognitive Load Theory. Cognitive Load Theory begins with the well-established fact that everyone's working memory can hold 7 ± 2 unique items. This quirk of the human brain is why phone numbers are 7 digits long. This quirk is also why we forget peoples’ names after just meeting them, leave the iron on when we leave the house, and become overwhelmed as students of new material. Once the intricacies of Cognitive Load are understood, it becomes possible to design learning environments to marshal the resources students have and guide them to success. Lessons learned from Cognitive Load Theory can and should be applied to learning astronomy. Classroom-ready ideas will be presented.

  5. Chemical fractionation resulting from the hypervelocity impact process on metallic targets

    Science.gov (United States)

    Libourel, Guy; Ganino, Clément; Michel, Patrick; Nakamura, Akiko

    2016-10-01

    In a regime of hypervelocity impact cratering, the internal energy deposited in target + projectile region is large enough to melt and/or vaporize part of the material involved, which expands rapidly away from the impact site. Fast and energetic impact processes have therefore important chemical consequences on the projectile and target rock transformations during major impact events. Several physical and chemical processes occurred indeed in the short duration of the impact, e.g., melting, coating, mixing, condensation, crystallization, redox reactions, quenching, etc., all concurring to alter both projectile and target composition on the irreversible way.In order to document such hypervelocity impact chemical fractionation, we have started a program of impact experiments by shooting doped (27 trace elements) millimeter–sized basalt projectiles on metallic target using a two stages light gas gun. With impact velocity in the range from 0.25 to 7 km.s-1, these experiments are aimed i) to characterize chemically and texturally all the post-mortem materials (e.g., target, crater, impact melt, condensates, and ejectas), in order ii) to make a chemical mass balance budget of the process, and iii) to relate it to the kinetic energy involved in the hypervelocity impacts for scaling law purpose. Irrespective of the incident velocities, our preliminary results show the importance of redox processes, the significant changes in the ejecta composition (e.g., iron enrichment) and the systematic coating of the crater by the impact melt [1]. On the target side, characterizations of the microstructure of the shocked iron alloys to better constrain the shielding processes. We also show how these results have great implications in our understanding on the current surface properties of small bodies, and chiefly in the case of M-type asteroids. [1] Ganino C, Libourel G, Nakamura AM & Michel P (2015) Goldschmidt Abstracts, 2015 990.

  6. Low Energy Effective Theory of QCD at High Isospin Chemical Potential

    CERN Document Server

    Cohen, Thomas D

    2015-01-01

    The goal of this paper is to arrive at a low energy effective theory of QCD with two massless flavors of quarks at very high isospin density and zero baryon density. In a seminal paper by Son and Stephanov in the year 2001, it was conjectured that the low energy dynamics of QCD with two light flavors at asymptotically high isospin density was described by that of a pure Yang-Mills effective Lagrangian. Since the existence of a first order deconfinement phase transition with increasing temperature is a feature of every pure SU(N) Yang-Mills theory with N greater than or equal to 3, the regime considered in this paper is also expected to exhibit a first order deconfinement phase transition with increasing temperature. However, the low energy constants(LEC) of this pure Yang-Mills theory have not been calculated till date. We calculate the LEC s for this effective theory which in turn enables us to calculate the critical temperature of the deconfinement transition as a function of the isospin chemical potential ...

  7. Developing density functional theory for Bose-Einstein condensates. The case of chemical bonding

    International Nuclear Information System (INIS)

    Since the nowadays growing interest in Bose-Einstein condensates due to the expanded experimental evidence on various atomic systems within optical lattices in weak and strong coupling regimes, the connection with Density Functional Theory is firstly advanced within the mean field framework at three levels of comprehension: the many-body normalization condition, Thomas-Fermi limit, and the chemical hardness closure with the inter-bosonic strength and universal Hohenberg-Kohn functional. As an application the traditional Heitler-London quantum mechanical description of the chemical bonding for homopolar atomic systems is reloaded within the non-linear Schrödinger (Gross-Pitaevsky) Hamiltonian; the results show that a two-fold energetic solution is registered either for bonding and antibonding states, with the bosonic contribution being driven by the square of the order parameter for the Bose-Einstein condensate density in free (gas) motion, while the associate wave functions remain as in classical molecular orbital model

  8. Developing density functional theory for Bose-Einstein condensates. The case of chemical bonding

    Energy Technology Data Exchange (ETDEWEB)

    Putz, Mihai V., E-mail: mvputz@cbg.uvt.ro [Laboratory of Physical and Computational Chemistry, Chemistry Department, West University of Timisoara, Str. Pestalozzi No. 16, 300115 Timisoara, Romania and Theoretical Physics Institute, Free University Berlin, Arnimallee 14, 14195 Berlin (Germany)

    2015-01-22

    Since the nowadays growing interest in Bose-Einstein condensates due to the expanded experimental evidence on various atomic systems within optical lattices in weak and strong coupling regimes, the connection with Density Functional Theory is firstly advanced within the mean field framework at three levels of comprehension: the many-body normalization condition, Thomas-Fermi limit, and the chemical hardness closure with the inter-bosonic strength and universal Hohenberg-Kohn functional. As an application the traditional Heitler-London quantum mechanical description of the chemical bonding for homopolar atomic systems is reloaded within the non-linear Schrödinger (Gross-Pitaevsky) Hamiltonian; the results show that a two-fold energetic solution is registered either for bonding and antibonding states, with the bosonic contribution being driven by the square of the order parameter for the Bose-Einstein condensate density in free (gas) motion, while the associate wave functions remain as in classical molecular orbital model.

  9. Analysis Of Names Of Organic Chemical Compounds By Using Parser Combinators And The Generative Lexicon Theory

    Directory of Open Access Journals (Sweden)

    Marcio de Souza Dias

    2011-11-01

    Full Text Available This work proposes OCLAS (Organic Chemistry Language Ambiguity Solver, an automatic system to analyze syntactically and semantically Organic Chemistry compound names and to generate the pictures of their chemical structures. If both parses detect that the input name corresponds to a theoreticallypossible organic chemical compound, the system generates its molecular structure picture, whether or not the name respects the current official nomenclature. This capacity of treating even names which, in spite of do not respect the constraints of the official nomenclatures, correspond to theoretically possible organic compound, represents an advance of OCLAS compared to other existing systems. OCLAS counts on the following tools: Generative Lexicon Theory (GLT, Parser Combinators and the Language Clean and an extension of the Xymtec package of Latex. The implemented system represents a helpful and friendly utilitarian as an automatic Organic Chemistry instructor.

  10. Analysis Of Names Of Organic Chemical Compounds By Using Parser Combinators And The Generative Lexicon Theory

    Directory of Open Access Journals (Sweden)

    Márcio de Souza Dias

    2011-10-01

    Full Text Available This work proposes OCLAS (Organic Chemistry Language Ambiguity Solver, an automatic system to analyze syntactically and semantically Organic Chemistry compound names and to generate the pictures of their chemical structures. If both parses detect that the input name corresponds to a theoretically possible organic chemical compound, the system generates its molecular structure picture, whether or not the name respects the current official nomenclature. This capacity of treating even names which, in spite of do not respect the constraints of the official nomenclatures, correspond to theoretically possible organic compound, represents an advance of OCLAS compared to other existing systems. OCLAS counts on the following tools: Generative Lexicon Theory (GLT, Parser Combinators and the Language Clean and an extension of the Xymtec package of Latex. The implemented system represents a helpful and friendly utilitarian as an automatic Organic Chemistry instructor.

  11. Analysis of marine ecological compensation for environmental risk caused by chemical spill based on game theory

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiwei; Yang Zhifeng; Huang Xinyu

    2009-01-01

    The problem of marine environmental risk is ultimately the result of game theory between the marine environmental managers and the enterprise of potential environmental risk.This paper analyzes the internal economic relationship that whether the "protection" policy is applied between the protection action of marine environmental managers and the chemical enterprise, The result shows that the key factor whether the enterprise adopt the "protection" policy or not is the amount of penalty and the government's cost of execution, and the compulsive ecological compensation is obligatory from the angle of stimulating the enterprise of canontcal action and adopting the "protection" policy.To build the ecological compensation mechanism based on the environmental risk will effectively improve the level of management in sea area and decrease the probability of chemical spill.

  12. Quantum chemical methods for the investigation of photoinitiated processes in biological systems: theory and applications.

    Science.gov (United States)

    Dreuw, Andreas

    2006-11-13

    With the advent of modern computers and advances in the development of efficient quantum chemical computer codes, the meaningful computation of large molecular systems at a quantum mechanical level became feasible. Recent experimental effort to understand photoinitiated processes in biological systems, for instance photosynthesis or vision, at a molecular level also triggered theoretical investigations in this field. In this Minireview, standard quantum chemical methods are presented that are applicable and recently used for the calculation of excited states of photoinitiated processes in biological molecular systems. These methods comprise configuration interaction singles, the complete active space self-consistent field method, and time-dependent density functional theory and its variants. Semiempirical approaches are also covered. Their basic theoretical concepts and mathematical equations are briefly outlined, and their properties and limitations are discussed. Recent successful applications of the methods to photoinitiated processes in biological systems are described and theoretical tools for the analysis of excited states are presented. PMID:17009357

  13. Impact Theory of Mass Extinctions and the Invertebrate Fossil Record

    Science.gov (United States)

    Alvarez, Walter; Kauffman, Erle G.; Surlyk, Finn; Alvarez, Luis W.; Asaro, Frank; Michel, Helen V.

    1984-03-01

    There is much evidence that the Cretaceous-Tertiary boundary was marked by a massive meteorite impact. Theoretical consideration of the consequences of such an impact predicts sharp extinctions in many groups of animals precisely at the boundary. Paleontological data clearly show gradual declines in diversity over the last 1 to 10 million years in various invertebrate groups. Reexamination of data from careful studies of the best sections shows that, in addition to undergoing the decline, four groups (ammonites, cheilostomate bryozoans, brachiopods, and bivalves) were affected by sudden truncations precisely at the iridium anomaly that marks the boundary. The paleontological record thus bears witness to terminal-Cretaceous extinctions on two time scales: a slow decline unrelated to the impact and a sharp truncation synchronous with and probably caused by the impact.

  14. Analysis of abused drugs by selected ion monitoring: quantitative comparison of electron impact and chemical ionization

    International Nuclear Information System (INIS)

    A comparison was made of the relative sensitivities of electron impact and chemical ionization when used for selected ion monitoring analysis of commonly abused drugs. For most of the drugs examined chemical ionization using ammonia as the reactant gas gave the largest single m/e ion current response per unit weight of sample. However, if maximum sensitivity is desired it is important to evaluate electron impact and chemical ionization with respect to both maximum response and degree of interference from background and endogenous materials

  15. Derivation of the chemical-equilibrium rate coefficient using scattering theory

    Science.gov (United States)

    Mickens, R. E.

    1977-01-01

    Scattering theory is applied to derive the equilibrium rate coefficient for a general homogeneous chemical reaction involving ideal gases. The reaction rate is expressed in terms of the product of a number of normalized momentum distribution functions, the product of the number of molecules with a given internal energy state, and the spin-averaged T-matrix elements. An expression for momentum distribution at equilibrium for an arbitrary molecule is presented, and the number of molecules with a given internal-energy state is represented by an expression which includes the partition function.

  16. Effect of discontinuities in Kohn-Sham-based chemical reactivity theory

    CERN Document Server

    Hellgren, M

    2012-01-01

    We provide a new derivation of a formula for the Fukui function of density-functional chemical reactivity theory which incorporates the discontinuities in the Kohn-Sham reference system. Orbital relaxations are described in terms of the exchange-correlation (XC) kernel, i.e., the derivative of the XC potential with respect to the density and it is shown that in order to correctly measure the reactivity toward a nucleophilic reagent a discontinuity of the XC kernel has to be taken into account. The importance of this finding is illustrated in model molecular systems.

  17. Areca Fiber Reinforced Epoxy Composites: Effect of Chemical Treatments on Impact Strength

    Directory of Open Access Journals (Sweden)

    S. Dhanalakshmi

    2015-06-01

    Full Text Available In this research work, impact strength of untreated, alkali treated, potassium permanganate treated, benzoyl chloride treated and acrylic acid treated areca fiber reinforced epoxy composites were studied under 40%, 50%, 60% and 70% fiber loadings. Impact strength increased with increase in fiber loading up to 60% and then showed a decline for all untreated and chemically treated areca fiber reinforced epoxy composites. The acrylic acid treated areca fiber reinforced epoxy composites with 60% fiber loading showed highest impact strength of 28.28 J/mm2 amongst all untreated and chemically treated areca/epoxy composites with same 60% fiber loading.

  18. The Ongoing Impact of Modular Localization on Particle Theory

    Science.gov (United States)

    Schroer, Bert

    2014-08-01

    Modular localization is the concise conceptual formulation of causal localization in the setting of local quantum physics. Unlike QM it does not refer to individual operators but rather to ensembles of observables which share the same localization region, as a result it explains the probabilistic aspects of QFT in terms of the impure KMS nature arising from the local restriction of the pure vacuum. Whereas it played no important role in the perturbation theory of low spin particles, it becomes indispensible for interactions which involve higher spin s≥1 fields, where is leads to the replacement of the operator (BRST) gauge theory setting in Krein space by a new formulation in terms of stringlocal fields in Hilbert space. The main purpose of this paper is to present new results which lead to a rethinking of important issues of the Standard Model concerning massive gauge theories and the Higgs mechanism. We place these new findings into the broader context of ongoing conceptual changes within QFT which already led to new nonperturbative constructions of models of integrable QFTs. It is also pointed out that modular localization does not support ideas coming from string theory, as extra dimensions and Kaluza-Klein dimensional reductions outside quasiclassical approximations. Apart from hologarphic projections on null-surfaces, holograhic relations between QFT in different spacetime dimensions violate the causal completeness property, this includes in particular the Maldacena conjecture. Last not least, modular localization sheds light onto unsolved problems from QFT's distant past since it reveals that the Einstein-Jordan conundrum is really an early harbinger of the Unruh effect.

  19. The Impact of Quantum Cosmology on Quantum Field Theory

    OpenAIRE

    Esposito, Giampiero

    1995-01-01

    The basic problem of quantum cosmology is the definition of the quantum state of the universe, with appropriate boundary conditions on Riemannian three-geometries. This paper describes recent progress in the corresponding analysis of quantum amplitudes for Euclidean Maxwell theory and linearized gravity. Within the framework of Faddeev-Popov formalism and zeta-function regularization, various choices of mixed boundary conditions lead to a deeper understanding of quantized gauge fields and qua...

  20. The Impact of Electronic Media Violence: Scientific Theory and Research

    OpenAIRE

    Huesmann, L. Rowell

    2007-01-01

    Since the early 1960s research evidence has been accumulating that suggests that exposure to violence in television, movies, video games, cell phones, and on the internet increases the risk of violent behavior on the viewer’s part just as growing up in an environment filled with real violence increases the risk of them behaving violently. In the current review this research evidence is critically assessed, and the psychological theory that explains why exposure to violence has detrimental eff...

  1. The ongoing impact of modular localization on particle theory

    CERN Document Server

    Schroer, Bert

    2014-01-01

    Modular localization is the concise conceptual formulation of causal localization in the setting of local quantum physics. Unlike QM it does not refer to individual operators but rather to ensembles of observables which share the same localization region, as a result it explains the probabilistic aspects of QFT in terms of the impure KMS nature arising from the local restriction of the pure vacuum. Whereas it played no important role in the perturbation theory of low spin particles, it becomes indispensible for interactions which involve higher spin s fields, where is leads to the replacement of the operator (BRST) gauge theory setting in Krein space by a new formulation in terms of stringlocal fields in Hilbert space. The main purpose of this paper is to present new results which lead to a rethinking of important issues of the Standard Model concerning massive gauge theories and the Higgs mechanism. We place these new findings into the broader context of ongoing conceptual changes within QFT which already le...

  2. Theory and Practice of Transboundary Environmental Impact Assessment

    NARCIS (Netherlands)

    Bastmeijer, C.J.; Koivurova, T.

    2008-01-01

    Environmental Impact Assessment (EIA) is a well-established instrument of environmental law and policy that aims to ensure that potential adverse environmental effects of human activities are assessed before decisions on such activities are made. The instrument is increasingly being applied in respe

  3. A Collective Impact Ionization Theory of Lock-On

    Energy Technology Data Exchange (ETDEWEB)

    HJALMARSON, HAROLD P.; KAMBOUR, CHARLES; KANG, SAMSOO; LOUBRIEL, GUILLERMO M.; MYLES, CHARLES W.; WAKE, DOUGLAS RAYMON; ZUTAVERN, FRED J.

    1999-09-02

    PhotoConductive semiconductor switches (PCSS's), such as optically-triggered GaAs switches, have been developed for a variety of applications. Such switches exhibit unique properties associated with lock-on, a phenomenon associated with bistable switching. In this paper lock-on is explained in terms of collective impact ionization.

  4. Including chemical-related impact categories in LCA on printed matter does it matter?

    DEFF Research Database (Denmark)

    Larsen, Henrik Fred; Hansen, Morten Søes; Hauschild, Michael Zwicky

    2004-01-01

    Introduction Existing product Life Cycle Assessments (LCA¡¦s) on offset printed matter all point at paper as the overall dominating contributor to the impacts from the life-cycle of this category of products. This dominating role of paper is primarily founded in the energy-related impact categories...... global warming, acidification and nutrification. The studies focus on energy consumption including the emissions and impact categories related to energy. The chemical-related impact categories comprising ecotoxicity and human toxicity are not included at all or only to a limited degree. In this paper we...... include these chemical-related impact categories by making use of some of the newest knowledge about emissions from the production at the printing industry combined with knowledge about the composition of the printing materials used during the production of offset printed matter. This paper is based...

  5. The limits of local correlation theory: electronic delocalization and chemically smooth potential energy surfaces.

    Science.gov (United States)

    Subotnik, Joseph E; Sodt, Alex; Head-Gordon, Martin

    2008-01-21

    Local coupled-cluster theory provides an algorithm for measuring electronic correlation quickly, using only the spatial locality of localized electronic orbitals. Previously, we showed [J. Subotnik et al., J. Chem. Phys. 125, 074116 (2006)] that one may construct a local coupled-cluster singles-doubles theory which (i) yields smooth potential energy surfaces and (ii) achieves near linear scaling. That theory selected which orbitals to correlate based only on the distances between the centers of different, localized orbitals, and the approximate potential energy surfaces were characterized as smooth using only visual identification. This paper now extends our previous algorithm in three important ways. First, locality is now based on both the distances between the centers of orbitals as well as the spatial extent of the orbitals. We find that, by accounting for the spatial extent of a delocalized orbital, one can account for electronic correlation in systems with some electronic delocalization using fast correlation methods designed around orbital locality. Second, we now enforce locality on not just the amplitudes (which measure the exact electron-electron correlation), but also on the two-electron integrals themselves (which measure the bare electron-electron interaction). Our conclusion is that we can bump integrals as well as amplitudes, thereby gaining a tremendous increase in speed and paradoxically increasing the accuracy of our LCCSD approach. Third and finally, we now make a rigorous definition of chemical smoothness as requiring that potential energy surfaces not support artificial maxima, minima, or inflection points. By looking at first and second derivatives from finite difference techniques, we demonstrate complete chemical smoothness of our potential energy surfaces (bumping both amplitudes and integrals). These results are significant both from a theoretical and from a computationally practical point of view. PMID:18205484

  6. Managing the effects of endocrine disrupting chemicals in wastewater-impacted streams

    Science.gov (United States)

    Bradley, Paul M.; Kolpin, Dana W.

    2013-01-01

    A revolution in analytical instrumentation circa 1920 greatly improved the ability to characterize chemical substances. This analytical foundation resulted in an unprecedented explosion in the design and production of synthetic chemicals during and post-World War II. What is now often referred to as the 2nd Chemical Revolution has provided substantial societal benefits; with modern chemical design and manufacturing supporting dramatic advances in medicine, increased food production, and expanding gross domestic products at the national and global scales as well as improved health, longevity, and lifestyle convenience at the individual scale. Presently, the chemical industry is the largest manufacturing sector in the United States (U.S.) and the second largest in Europe and Japan, representing approximately 5% of the Gross Domestic Product (GDP) in each of these countries. At the turn of the 21st century, the chemical industry was estimated to be worth more than $1.6 trillion and to employ over 10 million people, globally. During the first half of the 20th century, the chemical sector expanded rapidly, the chemical industry enjoyed a generally positive status in society, and chemicals were widely appreciated as fundamental to individual and societal quality of life. Starting in the 1960s, however, the environmental costs associated with the chemical industry increasingly became the focus, due in part to the impact of books like “Silent Spring” and “Our Stolen Future” and to a number of highly publicized environmental disasters. Galvanizing chemical industry disasters included the 1976 dioxin leak north of Milan, Italy, the Love Canal evacuations in Niagara, New York beginning in 1978, and the Union Carbide leak in Bhopal, India in 1984. Understanding the environmental impact of synthetic compounds is essential to any informed assessment of net societal benefit, for the simple reason that any chemical substance that is in commercial production or use will

  7. Vegetation change impacts on soil organic carbon chemical composition in subtropical forests

    Science.gov (United States)

    Guo, Xiaoping; Meng, Miaojing; Zhang, Jinchi; Chen, Han Y. H.

    2016-07-01

    Changes in the chemical composition of soil organic carbon (SOC) might strongly affect the global carbon cycle as it controls the SOC decomposition rate. Vegetation change associated with long-term land use changes is known to strongly impact the chemical composition of SOC; however, data on the impacts of vegetation change following disturbance events of short durations and succession that occur frequently in forest ecosystems via diverse management objectives on SOC chemical composition are negligible. Here we examined the impacts of vegetation changes on the chemical composition of SOC by sampling soils of native broad-leaved forests, planted mixed broad-leaved and coniferous forests, and tea gardens in eastern China. We used nuclear magnetic resonance spectroscopy to quantify SOC chemical composition. We found that among all components of SOC chemical composition, alkyl carbon (C) and aryl C were more liable to change with vegetation than other SOC components. Soil pH was negatively correlated to the relative abundances of alkyl C and N-alkyl C, and Shannon’s index of overstory plant species was positively correlated to the relative abundances of phenolic C and aromaticity. Our results suggest that vegetation changes following short disturbance events and succession may strongly alter SOC chemical composition in forest ecosystems.

  8. Vegetation change impacts on soil organic carbon chemical composition in subtropical forests.

    Science.gov (United States)

    Guo, Xiaoping; Meng, Miaojing; Zhang, Jinchi; Chen, Han Y H

    2016-01-01

    Changes in the chemical composition of soil organic carbon (SOC) might strongly affect the global carbon cycle as it controls the SOC decomposition rate. Vegetation change associated with long-term land use changes is known to strongly impact the chemical composition of SOC; however, data on the impacts of vegetation change following disturbance events of short durations and succession that occur frequently in forest ecosystems via diverse management objectives on SOC chemical composition are negligible. Here we examined the impacts of vegetation changes on the chemical composition of SOC by sampling soils of native broad-leaved forests, planted mixed broad-leaved and coniferous forests, and tea gardens in eastern China. We used nuclear magnetic resonance spectroscopy to quantify SOC chemical composition. We found that among all components of SOC chemical composition, alkyl carbon (C) and aryl C were more liable to change with vegetation than other SOC components. Soil pH was negatively correlated to the relative abundances of alkyl C and N-alkyl C, and Shannon's index of overstory plant species was positively correlated to the relative abundances of phenolic C and aromaticity. Our results suggest that vegetation changes following short disturbance events and succession may strongly alter SOC chemical composition in forest ecosystems. PMID:27403714

  9. The Impact of Labov's Contribution to general Linguistic Theory

    DEFF Research Database (Denmark)

    Gregersen, Frans; Cornips, Leonie

    2016-01-01

    century which is Chomskyan theoretical linguistics, i.e. as either a supplement or an alternative. Variation at the level of closely related languages, at the level of the language community, and at the level of the individual, have all been treated by Chomskyans under various headings, thus giving...... evidence that empirical results stemming from variationist sociolinguistics cannot be ignored. However, the treatment has not led to an integration of variation into Chomskyan theory, nor could it. In the final section we outline what a Labovian materialist alternative to Chomskyan idealism could be. We...

  10. The impact of electronic media violence: scientific theory and research.

    Science.gov (United States)

    Huesmann, L Rowell

    2007-12-01

    Since the early 1960s, research evidence has been accumulating that suggests that exposure to violence in television, movies, video games, cell phones, and on the Internet increases the risk of violent behavior on the viewer's part, just as growing up in an environment filled with real violence increases the risk of them behaving violently. In the current review this research evidence is critically assessed and the psychological theory that explains why exposure to violence has detrimental effects for both the short and long-term is elaborated. Finally the size of the "media violence effect" is compared with some other well-known threats to society to estimate how important a threat it should be considered. PMID:18047947

  11. Environmental Impact on Chemical/Oil Spill in the Persian Gulf

    OpenAIRE

    Haeger, Steven D.; Ward, Mathew; Peter C. Chu; Williams, Charles L.; Clem, Travis

    2008-01-01

    Seventh International Symposium on Environmental Problems in Coastal Regions An attack on, or chemical spill near, Iraq’s oil terminals could have disastrous effects on economy. The impact from chemical spill is highly dependent upon environmental conditions that can either adversely affect continued operations or hinder the safety of personnel. Operational planners’ ability to create legitimate scenarios to train and combat these situations is the key to continued safe ...

  12. Absolute Hydration Free Energies of Ions, Ion-Water Clusters, and Quasi-chemical Theory

    CERN Document Server

    Asthagiri, D; Ashbaugh, H S; Pratt, Lawrence R.

    2003-01-01

    Experimental studies on ion-water clusters have provided insights into the microscopic aspects of hydration phenomena. One common view is that extending those experimental studies to larger cluster sizes would give the single ion absolute hydration free energies not obtainable by classical thermodynamic methods. This issue is reanalyzed in the context of recent computations and molecular theories on ion hydration, particularly considering the hydration of H$^+$, Li$^+$, Na$^+$, and HO$^-$ ions and thence the hydration of neutral ion pairs. The hydration free energies of neutral pairs computed here are in good agreement with experimental results, whereas the calculated absolute hydration free energies, and the excess chemical potentials, deviate consistently from some recently tabulated hydration free energies based on ion-water cluster data. We show how the single ion absolute hydration free energies are not separated from the potential of the phase in recent analyses of ion-water cluster data, even in the li...

  13. The impact of chemical pollution on the resilience of soils under multiple stresses: A conceptual framework for future research.

    Science.gov (United States)

    Schaeffer, Andreas; Amelung, Wulf; Hollert, Henner; Kaestner, Matthias; Kandeler, Ellen; Kruse, Jens; Miltner, Anja; Ottermanns, Richard; Pagel, Holger; Peth, Stephan; Poll, Christian; Rambold, Gerhard; Schloter, Michael; Schulz, Stefanie; Streck, Thilo; Roß-Nickoll, Martina

    2016-10-15

    Soils are faced with man-made chemical stress factors, such as the input of organic or metal-containing pesticides, in combination with non-chemical stressors like soil compaction and natural disturbance like drought. Although multiple stress factors are typically co-occurring in soil ecosystems, research in soil sciences on this aspect is limited and focuses mostly on single structural or functional endpoints. A mechanistic understanding of the reaction of soils to multiple stressors is currently lacking. Based on a review of resilience theory, we introduce a new concept for research on the ability of polluted soil (xenobiotics or other chemical pollutants as one stressor) to resist further natural or anthropogenic stress and to retain its functions and structure. There is strong indication that pollution as a primary stressor will change the system reaction of soil, i.e., its resilience, stability and resistance. It can be expected that pollution affects the physiological adaption of organisms and the functional redundancy of the soil to further stress. We hypothesize that the recovery of organisms and chemical-physical properties after impact of a follow-up stressor is faster in polluted soil than in non-polluted soil, i.e., polluted soil has a higher dynamical stability (dynamical stability=1/recovery time), whereas resilience of the contaminated soil is lower compared to that of not or less contaminated soil. Thus, a polluted soil might be more prone to change into another system regime after occurrence of further stress. We highlight this issue by compiling the literature exemplarily for the effects of Cu contamination and compaction on soil functions and structure. We propose to intensify research on effects of combined stresses involving a multidisciplinary team of experts and provide suggestions for corresponding experiments. Our concept offers thus a framework for system level analysis of soils paving the way to enhance ecological theory. PMID:27372890

  14. Rate constants of chemical reactions from semiclassical transition state theory in full and one dimension

    Science.gov (United States)

    Greene, Samuel M.; Shan, Xiao; Clary, David C.

    2016-06-01

    Semiclassical Transition State Theory (SCTST), a method for calculating rate constants of chemical reactions, offers gains in computational efficiency relative to more accurate quantum scattering methods. In full-dimensional (FD) SCTST, reaction probabilities are calculated from third and fourth potential derivatives along all vibrational degrees of freedom. However, the computational cost of FD SCTST scales unfavorably with system size, which prohibits its application to larger systems. In this study, the accuracy and efficiency of 1-D SCTST, in which only third and fourth derivatives along the reaction mode are used, are investigated in comparison to those of FD SCTST. Potential derivatives are obtained from numerical ab initio Hessian matrix calculations at the MP2/cc-pVTZ level of theory, and Richardson extrapolation is applied to improve the accuracy of these derivatives. Reaction barriers are calculated at the CCSD(T)/cc-pVTZ level. Results from FD SCTST agree with results from previous theoretical and experimental studies when Richardson extrapolation is applied. Results from our implementation of 1-D SCTST, which uses only 4 single-point MP2/cc-pVTZ energy calculations in addition to those for conventional TST, agree with FD results to within a factor of 5 at 250 K. This degree of agreement and the efficiency of the 1-D method suggest its potential as a means of approximating rate constants for systems too large for existing quantum scattering methods.

  15. Rate constants of chemical reactions from semiclassical transition state theory in full and one dimension.

    Science.gov (United States)

    Greene, Samuel M; Shan, Xiao; Clary, David C

    2016-06-28

    Semiclassical Transition State Theory (SCTST), a method for calculating rate constants of chemical reactions, offers gains in computational efficiency relative to more accurate quantum scattering methods. In full-dimensional (FD) SCTST, reaction probabilities are calculated from third and fourth potential derivatives along all vibrational degrees of freedom. However, the computational cost of FD SCTST scales unfavorably with system size, which prohibits its application to larger systems. In this study, the accuracy and efficiency of 1-D SCTST, in which only third and fourth derivatives along the reaction mode are used, are investigated in comparison to those of FD SCTST. Potential derivatives are obtained from numerical ab initio Hessian matrix calculations at the MP2/cc-pVTZ level of theory, and Richardson extrapolation is applied to improve the accuracy of these derivatives. Reaction barriers are calculated at the CCSD(T)/cc-pVTZ level. Results from FD SCTST agree with results from previous theoretical and experimental studies when Richardson extrapolation is applied. Results from our implementation of 1-D SCTST, which uses only 4 single-point MP2/cc-pVTZ energy calculations in addition to those for conventional TST, agree with FD results to within a factor of 5 at 250 K. This degree of agreement and the efficiency of the 1-D method suggest its potential as a means of approximating rate constants for systems too large for existing quantum scattering methods. PMID:27369506

  16. Local and linear chemical reactivity response functions at finite temperature in density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Franco-Pérez, Marco, E-mail: francopj@mcmaster.ca, E-mail: ayers@mcmaster.ca, E-mail: jlgm@xanum.uam.mx, E-mail: avela@cinvestav.mx [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México, D.F. 09340 (Mexico); Ayers, Paul W., E-mail: francopj@mcmaster.ca, E-mail: ayers@mcmaster.ca, E-mail: jlgm@xanum.uam.mx, E-mail: avela@cinvestav.mx [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Gázquez, José L., E-mail: francopj@mcmaster.ca, E-mail: ayers@mcmaster.ca, E-mail: jlgm@xanum.uam.mx, E-mail: avela@cinvestav.mx [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México, D.F. 09340 (Mexico); Vela, Alberto, E-mail: francopj@mcmaster.ca, E-mail: ayers@mcmaster.ca, E-mail: jlgm@xanum.uam.mx, E-mail: avela@cinvestav.mx [Departamento de Química, Centro de Investigación y de Estudios Avanzados (Cinvestav), Av. Instituto Politécnico Nacional 2508, México, D.F. 07360 (Mexico)

    2015-12-28

    We explore the local and nonlocal response functions of the grand canonical potential density functional at nonzero temperature. In analogy to the zero-temperature treatment, local (e.g., the average electron density and the local softness) and nonlocal (e.g., the softness kernel) intrinsic response functions are defined as partial derivatives of the grand canonical potential with respect to its thermodynamic variables (i.e., the chemical potential of the electron reservoir and the external potential generated by the atomic nuclei). To define the local and nonlocal response functions of the electron density (e.g., the Fukui function, the linear density response function, and the dual descriptor), we differentiate with respect to the average electron number and the external potential. The well-known mathematical relationships between the intrinsic response functions and the electron-density responses are generalized to nonzero temperature, and we prove that in the zero-temperature limit, our results recover well-known identities from the density functional theory of chemical reactivity. Specific working equations and numerical results are provided for the 3-state ensemble model.

  17. On inelastic reactive collisions in kinetic theory of chemically reacting gas mixtures

    Science.gov (United States)

    Kremer, Gilberto M.; Silva, Adriano W.; Alves, Giselle M.

    2010-07-01

    A kinetic theory for a simple reversible reaction-characterized by a binary mixture of ideal gases whose constituents denoted by A and B undergo a reaction of the type A+A⇌B+B-is developed by considering the reactive collisions as inelastic ones. The geometry of the collision is taken into account in the line-of-centers differential cross section by allowing that a chemical reaction may occur only when the energy of the relative velocity in the direction of the line which joins the centers of the molecules at collision is larger than the activation energy. It is shown that the restitution coefficients: (i) depend explicitly on the reaction heat and on the relative translational energy in the direction of the line which joins the centers of the molecules during an inelastic collision; (ii) vanish when the reaction heat is zero; (iii) are larger or smaller than one depending on the direction of the reaction and on the sign of the reaction heat. First approximations to the distribution functions are determined from the system of Boltzmann equations for the last stage of a chemical reaction. It is shown that the deviations from the Maxwellian distribution functions and the production terms of the particle number densities: (i) vanish when the reaction heat is zero provided that the affinity is close to zero and (ii) are negative or positive depending on the sign of the reaction heat and on the direction of the reaction.

  18. A general theory of impacts and mass extinctions, and the consequences of large-body impact on the Earth

    Science.gov (United States)

    Rampino, M. R.

    1994-01-01

    The theory that large-body impacts are the primary cause of mass extinctions of life on the Earth now has a sound theoretical and observational foundation. A convergence of evidence suggests that the biosphere may be a sensitive detector of large impact events, which result in the recorded global mass extinction pulses. The astronomically observed flux of asteroids and comets in the neighborhood of the Earth, and the threshold impact size calculated to produce a global environment catastrophe, can be used to predict a time history of large impact events and related mass extinctions of life that agrees well with the record of approx. 24 extinction events in the last 540 m.y.

  19. Impact of supersonic and subsonic aircraft on ozone: Including heterogeneous chemical reaction mechanisms

    Science.gov (United States)

    Kinnison, Douglas E.; Wuebbles, Donald J.

    1994-01-01

    Preliminary calculations suggest that heterogeneous reactions are important in calculating the impact on ozone from emissions of trace gases from aircraft fleets. In this study, three heterogeneous chemical processes that occur on background sulfuric acid aerosols are included and their effects on O3, NO(x), Cl(x), HCl, N2O5, ClONO2 are calculated.

  20. Exploring the Impact of Argumentation on Pre-Service Science Teachers' Conceptual Understanding of Chemical Equilibrium

    Science.gov (United States)

    Aydeniz, Mehmet; Dogan, Alev

    2016-01-01

    This study examines the impact of argumentation on pre-service science teachers' (PST) conceptual understanding of chemical equilibrium. The sample consisted of 57 first-year PSTs enrolled in a teacher education program in Turkey. Thirty two of the 57 PSTs who participated in this study were in the experimental group and 25 in the control group.…

  1. Online Data Resources in Chemical Engineering Education: Impact of the Uncertainty Concept for Thermophysical Properties

    Science.gov (United States)

    Kim, Sun Hyung; Kang, Jeong Won; Kroenlein, Kenneth; Magee, Joseph W.; Diky, Vladimir; Muzny, Chris D.; Kazakov, Andrei F.; Chirico, Robert D.; Frenkel, Michael

    2013-01-01

    We review the concept of uncertainty for thermophysical properties and its critical impact for engineering applications in the core courses of chemical engineering education. To facilitate the translation of developments to engineering education, we employ NIST Web Thermo Tables to furnish properties data with their associated expanded…

  2. Building a model based on scientific consensus for Life Cycle Impact Assessment of chemicals:

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky; Huijbregts, Mark; Jolliet, Olivier;

    2008-01-01

    Achieving consensus among scientists is often a challenge - particularly in model development. In this article we describe a recent scientific consensus-building process for Life Cycle Impact Assessment (LCIA) models applied to chemical emissions - including the strategy, execution, and results...

  3. Impact of supersonic and subsonic aircraft on ozone: Including heterogeneous chemical reaction mechanisms

    International Nuclear Information System (INIS)

    Preliminary calculations suggest that heterogeneous reactions are important in calculating the impact on ozone from emissions of trace gases from aircraft fleets. In this study, three heterogeneous chemical processes that occur on background sulfuric acid aerosols are included and their effects on O3, NOx, Clx, HCl, N2O5, ClONO2 are calculated

  4. Legacy of a Chemical Factory Site: Contaminated Groundwater Impacts Stream Macroinvertebrates

    DEFF Research Database (Denmark)

    Rasmussen, Jes J.; McKnight, Ursula S.; Sonne, Anne Thobo;

    2016-01-01

    Legislative and managing entities of EU member states face a comprehensive task because the chemical and ecological impacts of contaminated sites on surface waters must be assessed. The ecological assessment is further complicated by the low availability or, in some cases, absence of ecotoxicity ...

  5. Assessment of impacts at the advanced test reactor as a result of chemical releases at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    This report provides an assessment of potential impacts at the Advanced Test Reactor Facility (ATR) resulting from accidental chemical spill at the Idaho Chemical Processing Plant (ICPP). Spills postulated to occur at the Lincoln Blvd turnoff to ICPP were also evaluated. Peak and time weighted average concentrations were calculated for receptors at the ATR facility and the Test Reactor Area guard station at a height above ground level of 1.0 m. Calculated concentrations were then compared to the 15 minute averaged Threshold Limit Value - Short Term Exposure Limit (TLV-STEL) and the 30 minute averaged Immediately Dangerous to Life and Health (IDLH) limit. Several different methodologies were used to estimate source strength and dispersion. Fifteen minute time weighted averaged concentrations of hydrofluoric acid and anhydrous ammonia exceeded TLV-STEL values for the cases considered. The IDLH value for these chemicals was not exceeded. Calculated concentrations of ammonium hydroxide, hexone, nitric acid, propane, gasoline, chlorine and liquid nitrogen were all below the TLV-STEL value

  6. Continuous, weighted Lorenz theory and applications to the study of fractional relative impact factors

    OpenAIRE

    Egghe, Leo

    2005-01-01

    This paper introduces weighted Lorenz curves of a continuous variable, extending the discrete theory as well as the non-weighted continuous model. Using publication scores (in function of time) as the weights and citation scores (in function of time) as the dependent variables, we can construct an “impact Lorenz curve” in which one can read the value of any fractional impact factor, i.e. an impact factor measured at the time that a certain fraction of the citations is obtained or measured at ...

  7. Researching the Impact of Teacher Professional Development Programmes Based on Action Research, Constructivism, and Systems Theory

    Science.gov (United States)

    Zehetmeier, Stefan; Andreitz, Irina; Erlacher, Willibald; Rauch, Franz

    2015-01-01

    This paper deals with the topic of professional development programmes' impact. Concepts and ideas of action research, constructivism, and systems theory are used as a theoretical framework and are combined to describe and analyse an exemplary professional development programme in Austria. Empirical findings from both quantitative and qualitative…

  8. Dust as interstellar catalyst - II. How chemical desorption impacts the gas

    CERN Document Server

    Cazaux, S; Dulieu, F; Hocuk, S

    2015-01-01

    Context. Interstellar dust particles, which represent 1% of the total mass, are recognized to be very powerful interstellar catalysts in star-forming regions. The presence of dust can have a strong impact on the chemical composition of molecular clouds. While observations show that many species that formed onto dust grains populate the gas phase, the process that transforms solid state into gas phase remains unclear. Aims. The aim of this paper is to consider the chemical desorption process, i.e. the process that releases solid species into the gas phase, in astrochemical models. These models allow determining the chemical composition of star-forming environments with an accurate treatment of the solid-phase chemistry. Methods. In paper I we derived a formula based on experimental studies with which we quantified the efficiencies of the chemical desorption process. Here we extend these results to astrophysical conditions. Results. The simulations of astrophysical environments show that the abundances of gas-p...

  9. Impact of self-reported multiple chemical sensitivity on everyday life: a qualitative study

    DEFF Research Database (Denmark)

    Skovbjerg, Sine; Brorson, Stig; Rasmussen, Alice;

    2009-01-01

    BACKGROUND: Multiple chemical sensitivity (MCS) is a descriptive term covering symptoms attributed to exposure to common airborne chemicals. There are no internationally accepted criteria, but it has been suggested that MCS is a chronic and disabling condition. However, details of the impact of M...... on individual consequences and the social and psychological factors that may be associated with MCS is needed in order to add to our understanding of this condition and to the provision of more satisfactory healthcare......., a duration of MCS of at least 1 year, and with different occupational conditions. RESULTS: MCS may severely influence different aspects of everyday life, including lifestyle, social relations, and occupational conditions. Avoiding common airborne chemicals was the most prevalent coping strategy, which...... implied creating a chemical-free living space and limiting social activities. Experiences with healthcare management were overall reported as negative in terms of not receiving acknowledgement of the reported symptoms. CONCLUSIONS: MCS may have serious implications for daily functioning. Further research...

  10. Dynamic behavior of chemical reactivity indices in density functional theory: A Bohn-Oppenheimer quantum molecular dynamics study

    Indian Academy of Sciences (India)

    Shubin Liu

    2005-09-01

    Dynamic behaviors of chemical concepts in density functional theory such as frontier orbitals (HOMO/LUMO), chemical potential, hardness, and electrophilicity index have been investigated in this work in the context of Bohn-Oppenheimer quantum molecular dynamics in association with molecular conformation changes. Exemplary molecular systems like CH$^{+}_{5}$ , Cl- (H2O)30 and Ca2+ (H2O)15 are studied at 300 K in the gas phase, demonstrating that HOMO is more dynamic than LUMO, chemical potential and hardness often fluctuate concurrently. It is argued that DFT concepts and indices may serve as a good framework to understand molecular conformation changes as well as other dynamic phenomena.

  11. Impact of Child Maltreatment on Attachment and Social Rank Systems: Introducing an Integrated Theory.

    Science.gov (United States)

    Sloman, Leon; Taylor, Peter

    2016-04-01

    Child maltreatment is a prevalent societal problem that has been linked to a wide range of social, psychological, and emotional difficulties. Maltreatment impacts on two putative evolved psychobiological systems in particular, the attachment system and the social rank system. The maltreatment may disrupt the child's ability to form trusting and reassuring relationships and also creates a power imbalance where the child may feel powerless and ashamed. The aim of the current article is to outline an evolutionary theory for understanding the impact of child maltreatment, focusing on the interaction between the attachment and the social rank system. We provide a narrative review of the relevant literature relating to child maltreatment and these two theories. This research highlights how, in instances of maltreatment, these ordinarily adaptive systems may become maladaptive and contribute to psychopathology. We identify a number of novel hypotheses that can be drawn from this theory, providing a guide for future research. We finally explore how this theory provides a guide for the treatment of victims of child maltreatment. In conclusion, the integrated theory provides a framework for understanding and predicting the consequences of maltreatment, but further research is required to test several hypotheses made by this theory.

  12. Impact of Child Maltreatment on Attachment and Social Rank Systems: Introducing an Integrated Theory.

    Science.gov (United States)

    Sloman, Leon; Taylor, Peter

    2016-04-01

    Child maltreatment is a prevalent societal problem that has been linked to a wide range of social, psychological, and emotional difficulties. Maltreatment impacts on two putative evolved psychobiological systems in particular, the attachment system and the social rank system. The maltreatment may disrupt the child's ability to form trusting and reassuring relationships and also creates a power imbalance where the child may feel powerless and ashamed. The aim of the current article is to outline an evolutionary theory for understanding the impact of child maltreatment, focusing on the interaction between the attachment and the social rank system. We provide a narrative review of the relevant literature relating to child maltreatment and these two theories. This research highlights how, in instances of maltreatment, these ordinarily adaptive systems may become maladaptive and contribute to psychopathology. We identify a number of novel hypotheses that can be drawn from this theory, providing a guide for future research. We finally explore how this theory provides a guide for the treatment of victims of child maltreatment. In conclusion, the integrated theory provides a framework for understanding and predicting the consequences of maltreatment, but further research is required to test several hypotheses made by this theory. PMID:25948552

  13. Perceived consequences of evolution: College students perceive negative personal and social impact in evolutionary theory

    Science.gov (United States)

    Brem, Sarah K.; Ranney, Michael; Schindel, Jennifer

    2003-03-01

    Evolutionary science has consequences for individuals and society, ranging from the way we interpret human behavior to our notions of spirituality and the purpose of our existence. Popular portrayals of evolution depict a paradoxical theory, a source of knowledge and human connections, but also a threat to our humanity and freedom. Using quantitative and qualitative methodology, we examined how college-educated adults (n = 135) from diverse ethnic and religious backgrounds perceive the impact of evolutionary theory on individuals and society. We identified a continuum of perspectives, ranging from strong creationist to strong evolutionist. Using the model of knowledge as an ecology (Demastes, Good, & Peebles, Science Education, 79, 637-666, 1995; Nardi & O'Day, Information ecologies: Using technology with heart, MIT Press, Cambridge, MA, 1999), we examined the relationships among participants' beliefs, their perceptions regarding the social and personal impact of evolutionary theory, their prior exposure to and knowledge of evolutionary theory, and their opinions regarding the teaching of evolution. Evolutionists and creationists differed in their prior exposure to evolutionary theory, and their opinions about some aspects of teaching, but showed striking similarities regarding perceived impact. All groups viewed the consequences of accepting evolutionary principles in a way that might be considered undesirable: increased selfishness and racism, decreased spirituality, and a decreased sense of purpose and self-determination. From a science education perspective, this one-sided interpretation is troublesome because it runs counter to the available evidence and theories in evolutionary science, and we consider ways of fostering more balanced presentation and appraisal of evolutionary theory.

  14. Correlation of 1H NMR Chemical Shift for Aqueous Solutions by Statistical Associating Fluid Theory Association Model

    Institute of Scientific and Technical Information of China (English)

    许波; 李浩然; 王从敏; 许映杰; 韩世钧

    2005-01-01

    1H NMR chemical shifts of binary aqueous mixtures of acylamide, alcohol, dimethyl sulphoxide (DMSO), and acetone are correlated by statistical associating fluid theory (SAFT) association model. The comparison between SAFT association model and Wilson equation shows that the former is better for dealing with aqueous solutions. Finally, the specialties of both models are discussed.

  15. Setting the most robust effluent level under severe uncertainty: application of information-gap decision theory to chemical management.

    Science.gov (United States)

    Yokomizo, Hiroyuki; Naito, Wataru; Tanaka, Yoshinari; Kamo, Masashi

    2013-11-01

    Decisions in ecological risk management for chemical substances must be made based on incomplete information due to uncertainties. To protect the ecosystems from the adverse effect of chemicals, a precautionary approach is often taken. The precautionary approach, which is based on conservative assumptions about the risks of chemical substances, can be applied selecting management models and data. This approach can lead to an adequate margin of safety for ecosystems by reducing exposure to harmful substances, either by reducing the use of target chemicals or putting in place strict water quality criteria. However, the reduction of chemical use or effluent concentrations typically entails a financial burden. The cost effectiveness of the precautionary approach may be small. Hence, we need to develop a formulaic methodology in chemical risk management that can sufficiently protect ecosystems in a cost-effective way, even when we do not have sufficient information for chemical management. Information-gap decision theory can provide the formulaic methodology. Information-gap decision theory determines which action is the most robust to uncertainty by guaranteeing an acceptable outcome under the largest degree of uncertainty without requiring information about the extent of parameter uncertainty at the outset. In this paper, we illustrate the application of information-gap decision theory to derive a framework for setting effluent limits of pollutants for point sources under uncertainty. Our application incorporates a cost for reduction in pollutant emission and a cost to wildlife species affected by the pollutant. Our framework enables us to settle upon actions to deal with severe uncertainty in ecological risk management of chemicals.

  16. Review of the toxicity of chemical mixtures: Theory, policy, and regulatory practice.

    Science.gov (United States)

    McCarty, L S; Borgert, C J

    2006-07-01

    An analysis of current mixture theory, policy, and practice was conducted by examining standard reference texts, regulatory guidance documents, and journal articles. Although this literature contains useful theoretical concepts, clear definitions of most terminology, and well developed protocols for study design and statistical analysis, no general theoretical basis for the mechanisms and interactions of mixture toxicity could be discerned. There is also a poor understanding of the relationship between exposure-based and internal received dose metrics. This confounds data interpretation and limits reliable determinations of the nature and extent of additivity. The absence of any generally accepted classification scheme for either modes/mechanisms of toxic action or of mechanisms of toxicity interactions is problematic as it produces a cycle in which research and policy are interdependent and mutually limiting. Current regulatory guidance depends heavily on determination of toxicological similarity concluded from the presence of a few prominent constituents, assumed from a common toxicological effect, or presumed from an alleged similar toxic mode/mechanism. Additivity, or the lack of it, is largely based on extrapolation of existing knowledge for single chemicals in this context. Thus, regulatory risk assessment protocols lack authoritative theoretical underpinnings, creating substantial uncertainty. Development of comprehensive classification schemes for modes/mechanisms of toxic action and mechanisms of interaction is needed to ensure a sound theoretical foundation for mixture-related regulatory activity and provide a firm basis for iterative hypothesis development and experimental testing.

  17. A Theory for Market Impact: How Order Flow Affects Stock Price

    CERN Document Server

    Gerig, Austin

    2007-01-01

    It is known that the impact of transactions on stock price (market impact) is a concave function of the size of the order, but there exists little quantitative theory that suggests why this is so. I develop a quantitative theory for the market impact of hidden orders (orders that reflect the true intention of buying and selling) that matches the empirically measured result and that reproduces some of the non-trivial and universal properties of stock returns (returns are percent changes in stock price). The theory is based on a simple premise, that the stock market can be modeled in a mechanical way - as a device that translates order flow into an uncorrelated price stream. Given that order flow is highly autocorrelated, this premise requires that market impact (1) depends on past order flow and (2) is asymmetric for buying and selling. I derive the specific form for the dependence in (1) by assuming that current liquidity responds to information about all currently active hidden orders (liquidity is a measure...

  18. Impacts of non-geometric moduli on effective theory of 5D supergravity

    CERN Document Server

    Sakamura, Yutaka

    2013-01-01

    5D supergravity generically has non-geometric moduli other than the radion that belong to 5D vector multiplets. We summarize the impacts of such moduli on 4D effective theory of 5D supergravity on S^1/Z_2. We mainly discuss the structure of the effective Kahler potential including the one-loop quantum corrections. As an illustrative example, we construct a model in which the size of the extra dimension is stabilized at an exponentially large value compared to the Planck length, which is similar to the LARGE volume scenario in string theory.

  19. The Younger Dryas ET Impact Theory and Terminal Pleistocene Mammalian Extinctions in North America

    Science.gov (United States)

    Erlandson, J. M.; Kennett, D. J.; Kennett, J.; Braje, T.; Culleton, B.

    2007-05-01

    Despite decades of intensive study and debate, no consensus has been reached on what caused the extinction of North America's mammalian megafauna at the end of the Pleistocene. In a scholarly standoff, prominent scientists have shown that neither "human overkill" or "climate change" models adequately account for the patterns found in the paleontological and archaeological records of North America. The Younger Dryas ET Impact theory may dramatically alter this debate, adding a catastrophic trigger to help explain the rapid extinction of many large mammals about 12,900 years ago. New data suggest that an extraterrestrial impact focused in northern and eastern North America may have devastated the megafauna through: (1) direct mortality caused by the impacts shock wave, debris, and massive wildfires; (2) dramatic reduction of terrestrial food supplies, rapid climatic change, and ecological reorganization; and (3) coup-de-grace effects of surviving human populations rapidly expanding after the impact.

  20. The impact of Einsteinian relativity and quantum physics theories on conceptualizations of the self in psychology

    Science.gov (United States)

    Rechberger, Elke Ruth

    1999-11-01

    Prior to the 1600s c.e., the church was the final authority for theories about the universe and humanity's role within it. However, when the mathematical theories put forth by scientists such as Copernicus and Galileo refuted traditional theological explanations about the cosmos, a shift to science as the premiere authority for theories was established, a tradition which continues to this day. In the following century, the work of Newton set forth a theory of the universe operating as a machine, where all things were potentially knowable, measurable, and predictable. His mechanistic hypotheses helped substantiate a corollary philosophy known as modernism. In the early 1900s, Einstein's theories about light and relativity began to indicate a universe significantly less absolute. His work set the stage for the development of quantum physics theories, whose hallmarks are probability, uncertainty, and complementarity. Quantum physics theories helped substantiate the philosophy known as postmodernism, where truth is nonexistent, reality is a subjectively constructed phenomenon, and the concept of an individual self is considered an illusion. Given that developments in physics have had profound impact across academic disciplines, including psychology, this study examine the effect of major revolutions in physics to corollary developments in theories about the self in psychology. It is the assertion of this work that modernist conceptualization of the self is one that is highly individualistic and defined in mechanistic terms, whereas the postmodern conceptualization of the self is significantly more socially constructed and has more interpersonally fluid, amorphous boundaries. Implications for conceptualizations of the self from either the modern or postmodern paradigm are discussed, as well as suggestions for future theory development.

  1. [Research in Mexico on the health impact of environmental chemical pollutants].

    Science.gov (United States)

    Ortega-Ceseña, J; Carreón-Valencia, T; López-Carrillo, L; Chávez-Ayala, R; Hernández-Avila, M

    1993-01-01

    This paper is intended to offer a qualitative and quantitative diagnosis on publications concerned with human health impact of exposure to environmental chemical pollutants in Mexico. The review of these subjects included scientific papers on studies carried out in Mexico, published both in Mexican and international journals. The articles were analyzed according to the following criteria: chemical pollutants, type of study and institution that conducted it, study population, design, and analysis of data. The article concludes that publications in this field are scarce. Moreover, this review showed that there is little diversity, limited methodology and an unequal distribution of the human and material resources for research. All this indicates a rudimentary level of scientific knowledge in Mexico regarding public health implications of chemical pollutants. PMID:8128296

  2. Bader’s Theory of Atoms in Molecules (AIM) and its Applications to Chemical Bonding

    Indian Academy of Sciences (India)

    P SHYAM VINOD KUMAR; V RAGHAVENDRA; V SUBRAMANIAN

    2016-10-01

    In this perspective article, the basic theory and applications of the “Quantum Theory of Atoms in Molecules” have been presented with examples from different categories of weak and hydrogen bonded molecular systems.

  3. Simulating behaviour change interventions based on the theory of planned behaviour: Impacts on intention and action.

    Science.gov (United States)

    Fife-Schaw, Chris; Sheeran, Paschal; Norman, Paul

    2007-03-01

    The theory of planned behaviour (TPB; Ajzen, 1991) has been used extensively to predict social and health behaviours. However, a critical test of the TPB is whether interventions that increased scores on the theory's predictors would engender behaviour change. The present research deployed a novel technique in order to provide this test. Statistical simulations were conducted on data for 30 behaviours (N=211) that estimated the impact of interventions that generated maximum positive changes in attitudes, subjective norms and perceived behavioural control (PBC) on subsequent intentions and behaviour. Findings indicated that interventions that maximized TPB variables had a substantial impact on behavioural intentions. Although TPB maximization increased the proportion of the sample that performed respective behaviours by 28% compared with baseline, the behaviour of a substantial minority of the sample (26%) did not change. The research also identified several interactions among TPB variables in predicting simulated intention and behaviour scores and investigated the mediating role of intentions in predicting behaviour. PMID:17355718

  4. The impact of new life sciences innovation on political theories of justice

    OpenAIRE

    Papaioannou, Theo

    2009-01-01

    New life sciences innovation offers the possibility of new conceptions of human nature with significant impact on liberal theories of justice. So far, nature as such has been thought to be something given and beyond human control. Thus, to define something as natural has meant the same thing as to relegate it to the realm of fortune or misfortune, rather than justice or injustice. However, the successful decoding of the human genome and subsequent advances in genomics-based technologies begi...

  5. Chemical precursor impact on the properties of Cu2ZnSnS4 absorber layer

    Science.gov (United States)

    Vashistha, Indu B.; Sharma, Mahesh C.; Sharma, S. K.

    2016-04-01

    In present work impact of different chemical precursor on the deposition of solar absorber layer Cu2ZnSnS4 (CZTS) were studied by Chemical Bath Deposition (CBD) method without using expensive vacuum facilities and followed by annealing. As compared to the other deposition methods, CBD method is interesting one because it is simple, reproducible, non-hazardous, cost effective and well suited for producing large-area thin films at low temperatures, although effect of precursors and concentration plays a vital role in the deposition. So, the central theme of this work is optimizing and controlling of chemical reactions for different chemical precursors. Further Effect of different chemical precursors i.e. sulphate and chloride is analyzed by structural, morphological, optical and electrical properties. The X-ray diffraction (XRD) of annealed CZTS thin film revealed that films were polycrystalline in nature with kestarite tetragonal crystal structure. The Atomic Force micrographs (AFM) images indicated total coverage compact film and as well as growth of crystals. The band gap of annealed CZTS films was found in the range of optimal band gap by absorption spectroscopy.

  6. The Lack of Chemical Equilibrium does not Preclude the Use of the Classical Nucleation Theory in Circumstellar Outflows

    Science.gov (United States)

    Paquette, John A.; Nuth, Joseph A., III

    2011-01-01

    Classical nucleation theory has been used in models of dust nucleation in circumstellar outflows around oxygen-rich asymptotic giant branch stars. One objection to the application of classical nucleation theory (CNT) to astrophysical systems of this sort is that an equilibrium distribution of clusters (assumed by CNT) is unlikely to exist in such conditions due to a low collision rate of condensable species. A model of silicate grain nucleation and growth was modified to evaluate the effect of a nucleation flux orders of magnitUde below the equilibrium value. The results show that a lack of chemical equilibrium has only a small effect on the ultimate grain distribution.

  7. Chemical footprint method for improved communication of freshwater ecotoxicity impacts in the context of ecological limits.

    Science.gov (United States)

    Bjørn, Anders; Diamond, Miriam; Birkved, Morten; Hauschild, Michael Zwicky

    2014-11-18

    The ecological footprint method has been successful in communicating environmental impacts of anthropogenic activities in the context of ecological limits. We introduce a chemical footprint method that expresses ecotoxicity impacts from anthropogenic chemical emissions as the dilution needed to avoid freshwater ecosystem damage. The indicator is based on USEtox characterization factors with a modified toxicity reference point. Chemical footprint results can be compared to the actual dilution capacity within the geographic vicinity receiving the emissions to estimate whether its ecological limit has been exceeded and hence whether emissions can be expected to be environmentally sustainable. The footprint method was illustrated using two case studies. The first was all inventoried emissions from European countries and selected metropolitan areas in 2004, which indicated that the dilution capacity was likely exceeded for most European countries and all landlocked metropolitan areas. The second case study indicated that peak application of pesticides alone was likely to exceed Denmark's freshwater dilution capacity in 1999-2011. The uncertainty assessment showed that better spatially differentiated fate factors would be useful and pointed out other major sources of uncertainty and some opportunities to reduce these. PMID:25347848

  8. The impact of infield biomass burning on PM levels and its chemical composition.

    Science.gov (United States)

    Dambruoso, P; de Gennaro, G; Di Gilio, A; Palmisani, J; Tutino, M

    2014-12-01

    In the South of Italy, it is common for farmers to burn pruning waste from olive trees in spring. In order to evaluate the impact of the biomass burning source on the physical and chemical characteristics of the particulate matter (PM) emitted by these fires, a PM monitoring campaign was carried out in an olive grove. Daily PM10 samples were collected for 1 week, when there were no open fires, and when biomass was being burned, and at two different distances from the fires. Moreover, an optical particle counter and a polycyclic aromatic hydrocarbon (PAH) analyzer were used to measure the high time-resolved dimensional distribution of particles emitted and total PAHs concentrations, respectively. Chemical analysis of PM10 samples identified organic and inorganic components such as PAHs, ions, elements, and carbonaceous fractions (OC, EC). Analysis of the collected data showed the usefulness of organic and inorganic tracer species and of PAH diagnostic ratios for interpreting the impact of biomass fires on PM levels and on its chemical composition. Finally, high time-resolved monitoring of particle numbers and PAH concentrations was performed before, during, and after biomass burning, and these concentrations were seen to be very dependent on factors such as weather conditions, combustion efficiency, and temperature (smoldering versus flaming conditions), and moisture content of the wood burned. PMID:24310905

  9. Advancing the theory and practice of impact assessment: Setting the research agenda

    International Nuclear Information System (INIS)

    Impact assessment has been in place for over 40 years and is now practised in some form in all but two of the world's nations. In this paper we reflect on the state of the art of impact assessment theory and practice, focusing on six well-established forms: EIA, SEA, policy assessment, SIA, HIA and sustainability assessment. We note that although the fundamentals of impact assessment have their roots in the US National Environmental Policy Act 1969 (NEPA) each branch of the field is distinct in also drawing on other theoretical and conceptual bases that in turn shape the prevailing discourse in each case, generating increasing degrees of specialisation within each sub-field. Against this backdrop, we consider the strengths and weaknesses of collective impact assessment practice, concluding that although there are substantial strengths, the plethora of specialist branches is generating a somewhat confusing picture and lack of clarity regarding how the pieces of the impact assessment jigsaw puzzle fit together. We use this review to suggest an overarching research agenda that will enable impact assessment to evolve in line with changing expectations for what it should deliver. -- Highlights: ► Strengths, weakness, opportunities and threats for IA are explored in this paper ► EIA, SEA, policy assessment, SIA, HIA and sustainability assessment are reviewed ► Diversity of practice is both a strength and weakness in the current economic climate ► There are opportunities to simplify IA by focusing on common and fundamental elements ► Continued research into theory related to IA effectiveness is also essential

  10. Free energy of liquid water on the basis of quasi-chemical theory and ab initio molecular dynamics

    CERN Document Server

    Asthagiri, D; Kress, J D; Pratt, Lawrence R.

    2003-01-01

    We use ab initio molecular dynamics as a basis for quasi-chemical theory evaluation of the free energy of water near conventional liquid thermodynamic states. The PW91, PBE, and revised PBE (rPBE) functionals are employed. The oxygen radial density distribution, gOO(r), using the rPBE functional is in reasonable agreement with current experiments, whereas the PW91 and PBE functionals predict a more structured gOO(r). The diffusion coefficient with the rPBE functional is in reasonable accord with experiments. Using a maximum entropy procedure, we obtain x_0 from the coordination number distribution x_n for oxygen atoms having n neighbors. Likewise, we obtain p_0 from p_n, the probability of observing cavities of specified radius containing n water molecules. The probability x_0 is a measure of the local chemical interactions and is central to the quasi-chemical theory of solutions. The probability p_0, central to the theory of liquids, is a measure of the free energy required to open cavities of defined sizes ...

  11. Chemical Assignment of Symmetry-Adapted Perturbation Theory Interaction Energy Components: The Functional-Group SAPT Partition.

    Science.gov (United States)

    Parrish, Robert M; Parker, Trent M; Sherrill, C David

    2014-10-14

    Recently, we introduced an effective atom-pairwise partition of the many-body symmetry-adapted perturbation theory (SAPT) interaction energy decomposition, producing a method known as atomic SAPT (A-SAPT) [Parrish, R. M.; Sherrill, C. D. J. Chem. Phys. 2014, 141, 044115]. A-SAPT provides ab initio atom-pair potentials for force field development and also automatic visualizations of the spatial contributions of noncovalent interactions, but often has difficulty producing chemically useful partitions of the electrostatic energy, due to the buildup of oscillating partial charges on adjacent functional groups. In this work, we substitute chemical functional groups in place of atoms as the relevant local quasiparticles in the partition, resulting in a functional-group-pairwise partition denoted as functional-group SAPT (F-SAPT). F-SAPT assigns integral sets of local occupied electronic orbitals and protons to chemical functional groups and linking σ bonds. Link-bond contributions can be further assigned to chemical functional groups to simplify the analysis. This approach yields a SAPT partition between pairs of functional groups with integral charge (usually neutral), preventing oscillations in the electrostatic partition. F-SAPT qualitatively matches chemical intuition and the cut-and-cap fragmentation technique but additionally yields the quantitative many-body SAPT interaction energy. The conceptual simplicity, chemical utility, and computational efficiency of F-SAPT is demonstrated in the context of phenol dimer, proflavine(+)-DNA intercalation, and a cucurbituril host-guest inclusion complex. PMID:26588139

  12. Environmental impact on the Northern Persian Gulf: a mine drift and chemical spill study centered on Iraq's oil terminals using Navy's ocean-atmospheric physical and chemical models

    OpenAIRE

    Williams, Charles L.

    2007-01-01

    Approved for public release; distribution is unlimited. An attack on, or chemical spill near, Iraq's oil terminals could have disastrous effects on Iraq's economy. The impacts from a drifting mine or chemical spill are highly dependent on environmental conditions that can either adversely effect continued operations or hinder the safety of personnel. Operation Planners' ability to create legitimate scenarios to train and combat these situations is key to continued safe operations of the ...

  13. The impact of chemical differentiation of white dwarfs on thermonuclear supernovae

    CERN Document Server

    Bravo, Eduardo; García-Berro, Enrique; Domínguez, Inmaculada

    2010-01-01

    Gravitational settling of 22Ne in cooling white dwarfs has been suggested to affect the outcome of thermonuclear supernovae. We investigate how the supernova energetics and nucleosynthesis are affected by this process. This is done using realistic chemical profiles obtained from state-of-the-art white dwarf cooling sequences. The cooling sequences provide a link between the white dwarf chemical structure and the age of the supernova progenitor system. The cooling sequence of a 1 M_sun white dwarf has been computed until freezing using an up-to-date stellar evolutionary code. Thereafter we have computed explosions of both Chandrasekhar mass and sub-Chandrasekhar mass white dwarfs, assuming spherical symmetry and neglecting convective mixing during the pre-supernova carbon simmering phase in order to maximize the effects of chemical separation. Neither gravitational settling of 22Ne nor chemical differentiation of 12C and 16O have an appreciable impact on the properties of Type Ia supernovae, unless there is a ...

  14. Estimated Energy Savings and Financial Impacts of Nanomaterials by Design on Selected Applications in the Chemical Industry

    Energy Technology Data Exchange (ETDEWEB)

    Thayer, Gary R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roach, J. Fred [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dauelsberg, Lori [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2006-03-01

    This study provides a preliminary analysis of the potential impact that nanotechnology could have on energy efficiency, economic competitiveness, waste reduction, and productivity, in the chemical and related industries.

  15. The impact of the chemical synthesis on the magnetic properties of intermetallic PdFe nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos-Rubio, I.; Insausti, M.; Muro, I. Gil de [Universidad del País Vasco, UPV/EHU, Dpto. de Química Inorgánica (Spain); Arias-Duque, D. Carolina; Hernández-Garrido, Juan Carlos [Universidad de Cadiz, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias (Spain); Rojo, T.; Lezama, L., E-mail: luis.lezama@ehu.es [Universidad del País Vasco, UPV/EHU, Dpto. de Química Inorgánica (Spain)

    2015-05-15

    Palladium-rich Iron nanoparticles in the 4–8 nm range have been produced by a combination of two methods: the thermal decomposition of organometallic precursors and the reduction of metallic salts by a polyol. Herein, it is shown how the details of the synthesis have a striking impact on the magnetic and morphological properties of the final products. In the synthesis of these bimetallic nanoparticles, the use of high reaction temperatures plays an essential role in attaining good chemical homogeneity, which has proved to have a key influence on the magnetic properties. Magnetic characterization has been performed by electron magnetic resonance and magnetization measurements, which have confirmed the superparamagnetic-like behavior at room temperature. No clear traces of magnetic polarization in palladium atoms have been detected. The combination of long-term stability and homogeneous chemical and magnetic properties makes these particles very suitable for a wide range of applications in nanotechnology.

  16. NSR&D FY15 Final Report. Modeling Mechanical, Thermal, and Chemical Effects of Impact

    Energy Technology Data Exchange (ETDEWEB)

    Long, Christopher Curtis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ma, Xia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zhang, Duan Zhong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-02

    The main goal of this project is to develop a computer model that explains and predicts coupled mechanical, thermal and chemical responses of HE under impact and friction insults. The modeling effort is based on the LANL-developed CartaBlanca code, which is implemented with the dual domain material point (DDMP) method to calculate complex and coupled thermal, chemical and mechanical effects among fluids, solids and the transitions between the states. In FY 15, we have implemented the TEPLA material model for metal and performed preliminary can penetration simulation and begun to link with experiment. Currently, we are working on implementing a shock to detonation transition (SDT) model (SURF) and JWL equation of state.

  17. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  18. Risk Assessment for Children Exposed to Beach Sands Impacted by Oil Spill Chemicals

    Directory of Open Access Journals (Sweden)

    Jennifer C. Black

    2016-08-01

    Full Text Available Due to changes in the drilling industry, oil spills are impacting large expanses of coastlines, thereby increasing the potential for people to come in contact with oil spill chemicals. The objective of this manuscript was to evaluate the health risk to children who potentially contact beach sands impacted by oil spill chemicals from the Deepwater Horizon disaster. To identify chemicals of concern, the U.S. Environmental Protection Agency’s (EPA’s monitoring data collected during and immediately after the spill were evaluated. This dataset was supplemented with measurements from beach sands and tar balls collected five years after the spill. Of interest is that metals in the sediments were observed at similar levels between the two sampling periods; some differences were observed for metals levels in tar balls. Although PAHs were not observed five years later, there is evidence of weathered-oil oxidative by-products. Comparing chemical concentration data to baseline soil risk levels, three metals (As, Ba, and V and four PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and dibenz[a,h]anthracene were found to exceed guideline levels prompting a risk assessment. For acute or sub-chronic exposures, hazard quotients, computed by estimating average expected contact behavior, showed no adverse potential health effects. For cancer, computations using 95% upper confidence limits for contaminant concentrations showed extremely low increased risk in the 10−6 range for oral and dermal exposure from arsenic in sediments and from dermal exposure from benzo[a]pyrene and benz[a]anthracene in weathered oil. Overall, results suggest that health risks are extremely low, given the limitations of available data. Limitations of this study are associated with the lack of toxicological data for dispersants and oil-spill degradation products. We also recommend studies to collect quantitative information about children’s beach play habits, which are

  19. Risk Assessment for Children Exposed to Beach Sands Impacted by Oil Spill Chemicals.

    Science.gov (United States)

    Black, Jennifer C; Welday, Jennifer N; Buckley, Brian; Ferguson, Alesia; Gurian, Patrick L; Mena, Kristina D; Yang, Ill; McCandlish, Elizabeth; Solo-Gabriele, Helena M

    2016-01-01

    Due to changes in the drilling industry, oil spills are impacting large expanses of coastlines, thereby increasing the potential for people to come in contact with oil spill chemicals. The objective of this manuscript was to evaluate the health risk to children who potentially contact beach sands impacted by oil spill chemicals from the Deepwater Horizon disaster. To identify chemicals of concern, the U.S. Environmental Protection Agency's (EPA's) monitoring data collected during and immediately after the spill were evaluated. This dataset was supplemented with measurements from beach sands and tar balls collected five years after the spill. Of interest is that metals in the sediments were observed at similar levels between the two sampling periods; some differences were observed for metals levels in tar balls. Although PAHs were not observed five years later, there is evidence of weathered-oil oxidative by-products. Comparing chemical concentration data to baseline soil risk levels, three metals (As, Ba, and V) and four PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and dibenz[a,h]anthracene) were found to exceed guideline levels prompting a risk assessment. For acute or sub-chronic exposures, hazard quotients, computed by estimating average expected contact behavior, showed no adverse potential health effects. For cancer, computations using 95% upper confidence limits for contaminant concentrations showed extremely low increased risk in the 10(-6) range for oral and dermal exposure from arsenic in sediments and from dermal exposure from benzo[a]pyrene and benz[a]anthracene in weathered oil. Overall, results suggest that health risks are extremely low, given the limitations of available data. Limitations of this study are associated with the lack of toxicological data for dispersants and oil-spill degradation products. We also recommend studies to collect quantitative information about children's beach play habits, which are necessary to more

  20. Risk Assessment for Children Exposed to Beach Sands Impacted by Oil Spill Chemicals

    Science.gov (United States)

    Black, Jennifer C.; Welday, Jennifer N.; Buckley, Brian; Ferguson, Alesia; Gurian, Patrick L.; Mena, Kristina D.; Yang, Ill; McCandlish, Elizabeth; Solo-Gabriele, Helena M.

    2016-01-01

    Due to changes in the drilling industry, oil spills are impacting large expanses of coastlines, thereby increasing the potential for people to come in contact with oil spill chemicals. The objective of this manuscript was to evaluate the health risk to children who potentially contact beach sands impacted by oil spill chemicals from the Deepwater Horizon disaster. To identify chemicals of concern, the U.S. Environmental Protection Agency’s (EPA’s) monitoring data collected during and immediately after the spill were evaluated. This dataset was supplemented with measurements from beach sands and tar balls collected five years after the spill. Of interest is that metals in the sediments were observed at similar levels between the two sampling periods; some differences were observed for metals levels in tar balls. Although PAHs were not observed five years later, there is evidence of weathered-oil oxidative by-products. Comparing chemical concentration data to baseline soil risk levels, three metals (As, Ba, and V) and four PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and dibenz[a,h]anthracene) were found to exceed guideline levels prompting a risk assessment. For acute or sub-chronic exposures, hazard quotients, computed by estimating average expected contact behavior, showed no adverse potential health effects. For cancer, computations using 95% upper confidence limits for contaminant concentrations showed extremely low increased risk in the 10−6 range for oral and dermal exposure from arsenic in sediments and from dermal exposure from benzo[a]pyrene and benz[a]anthracene in weathered oil. Overall, results suggest that health risks are extremely low, given the limitations of available data. Limitations of this study are associated with the lack of toxicological data for dispersants and oil-spill degradation products. We also recommend studies to collect quantitative information about children’s beach play habits, which are necessary to more

  1. Risk Assessment for Children Exposed to Beach Sands Impacted by Oil Spill Chemicals.

    Science.gov (United States)

    Black, Jennifer C; Welday, Jennifer N; Buckley, Brian; Ferguson, Alesia; Gurian, Patrick L; Mena, Kristina D; Yang, Ill; McCandlish, Elizabeth; Solo-Gabriele, Helena M

    2016-08-27

    Due to changes in the drilling industry, oil spills are impacting large expanses of coastlines, thereby increasing the potential for people to come in contact with oil spill chemicals. The objective of this manuscript was to evaluate the health risk to children who potentially contact beach sands impacted by oil spill chemicals from the Deepwater Horizon disaster. To identify chemicals of concern, the U.S. Environmental Protection Agency's (EPA's) monitoring data collected during and immediately after the spill were evaluated. This dataset was supplemented with measurements from beach sands and tar balls collected five years after the spill. Of interest is that metals in the sediments were observed at similar levels between the two sampling periods; some differences were observed for metals levels in tar balls. Although PAHs were not observed five years later, there is evidence of weathered-oil oxidative by-products. Comparing chemical concentration data to baseline soil risk levels, three metals (As, Ba, and V) and four PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and dibenz[a,h]anthracene) were found to exceed guideline levels prompting a risk assessment. For acute or sub-chronic exposures, hazard quotients, computed by estimating average expected contact behavior, showed no adverse potential health effects. For cancer, computations using 95% upper confidence limits for contaminant concentrations showed extremely low increased risk in the 10(-6) range for oral and dermal exposure from arsenic in sediments and from dermal exposure from benzo[a]pyrene and benz[a]anthracene in weathered oil. Overall, results suggest that health risks are extremely low, given the limitations of available data. Limitations of this study are associated with the lack of toxicological data for dispersants and oil-spill degradation products. We also recommend studies to collect quantitative information about children's beach play habits, which are necessary to more

  2. Impact of dust storm on chemical species of S, Cl and Ca in Shanghai atmosphere particles

    International Nuclear Information System (INIS)

    Background: Dust storm originated from the northwest region of China brought dust particles for Shanghai every spring, which resulted in serious particulate pollution. However, the studies of the impact of dust storm on the Shanghai atmospheric aerosols were limited to the concentrations of ions and elements. It is considered that the chemical species of atmospheric aerosols were much more necessary for the evaluation of the impact of dust storm on the particulate pollution in Shanghai. Purpose: Based on the elements concentration variations, backward trajectories of air masses and chlorine, calcium, sulfur species in aerosols during the dust event, the impact of dust storm on the chemical species of aerosols in Shanghai was studied. Methods: Elements concentrations of the samples were analyzed by X-ray fluorescence (XRF) based on synchrotron radiation. To identify the potential importance of different source regions on aerosol composition during dust events, the air mass trajectories were calculated by using the model HYSPLIT version 4 developed by NOAA/ARL. Chemical species of S, Cl, Ca were analyzed by synchrotron radiation X-ray absorption near edge structure (XANES). Sulfur K-edge XANES is capable of distinguishing various sulfate species in a non-destructive way and we used linear combination fitting procedure to quantify the concentrations of sulfate species in PM. Results: Elements concentration variations during the dust storm period showed that crust elements (Si, Al, Ca, K, Mg, Fe, Ti) in particles increased substantially during dust storm. However, pollution elements (S, Zn, Pb, Cu, V, Cr, As) from local region decreased by the clean effect of dust storm. Combined XANES of S, Cl, Ca in particulate samples with backward trajectories, the possible sources and reasons of their chemical species were studied. During dust storm, sulfur mainly existed as CaSO4·2H2O, Cl existed as organic chloride and Cl-, Ca existed as CaCO3. In the samples of other days

  3. Nanotopography Impact in Shallow Trench Isolation Chemical Mechanical Polishing-Dependence on Slurry Characteristics

    Institute of Scientific and Technical Information of China (English)

    Jea-Gun Park; Takeo Katoh; Ungyu Paik

    2004-01-01

    The nanotopography of the surface of silicon wafers has become an important issue in ULSI device manufacturing since it affects the post-chemical mechanical polishing (post-CMP) uniformity of the thickness deviation of dielectric films. In this study, the nanotopography impact was investigated in terms of its dependence on the characteristics of ceriabased slurries, such as the abrasive size, the grain size of the polycrystalline abrasive and the surfactant added to the slurry. It was found that the magnitude of the post-CMP oxide thickness deviation due to nanotopography increased with the surfactant concentration in the case of smaller abrasives but was almost independent of the concentration in the case of larger abrasives. The grain size of the polycrystalline abrasive did not affect the nanotopography impact.

  4. Incorporation of environmental impact criteria in the design and operation of chemical processes

    Directory of Open Access Journals (Sweden)

    P.E. Bauer

    2004-09-01

    Full Text Available Environmental impact assessment is becoming indispensable for the design and operation of chemical plants. Structured and consistent methods for this purpose have experienced a rapid development. The more rigorous and sophisticated these methods become, the greater is the demand for convenient tools. On the other hand, despite the incredible advances in process simulators, some aspects have still not been sufficiently covered. To date, applications of these programs to quantify environmental impacts have been restricted to straightforward examples of steady-state processes. In this work, a life-cycle assessment implementation with the aim of process design will be described, with a brief discussion of a dynamic simulation for analysis of transient state operations, such as process start-up. A case study shows the importance of this analysis in making possible operation at a high performance level with reduced risks to the environment.

  5. The impact of intellectual ability and metacognition on learning: New support for the threshold of problematicity theory

    NARCIS (Netherlands)

    Prins, Frans; Veenman, Marcel; Elshout, Jan

    2009-01-01

    Prins, F.J., Veenman, M.V.J., & Elshout, J.J. (2006). The impact of intellectual ability and metacognition on learning: New support for the threshold of problematicity theory. Learning & Instruction, 16 , 374-387.

  6. The Nature of the Chemical Process; 1, Symmetry Evolution - Revised Information Theory, Similarity Principle and Ugly Symmetry

    CERN Document Server

    Lin, S K

    2001-01-01

    Three laws of information theory have been proposed. Labeling by introducing nonsymmetry and formatting by introducing symmetry are defined. The function L (L=lnw, w is the number of microstates, or the sum of entropy and information, L=S+I) of the universe is a constant (the first law of information theory). The entropy S of the universe tends toward a maximum (the second law law of information theory). For a perfect symmetric static structure, the information is zero and the static entropy is the maximum (the third law law of information theory). Based on the Gibbs inequality and the second law of the revised information theory we have proved the similarity principle (a continuous higher similarity-higher entropy relation after the rejection of the Gibbs paradox) and proved the Curie-Rosen symmetry principle (a higher symmetry-higher stability relation) as a special case of the similarity principle. Some examples in chemical physics have been given. Spontaneous processes of all kinds of molecular interactio...

  7. Social impact theory based modeling for security analysis in the nuclear fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Tae Ho [Systemix Global Co. Ltd., Seoul (Korea, Republic of)

    2015-03-15

    The nuclear fuel cycle is investigated for the perspective of the nuclear non-proliferation. The random number generation of the Monte-Carlo method is utilized for the analysis. Five cases are quantified by the random number generations. These values are summed by the described equations. The higher values are shown in 52{sup nd} and 73{sup rd} months. This way could be a useful obligation in the license of the plant construction. The security of the nuclear fuel cycle incorporated with nuclear power plants (NPPs) is investigated using social impact theory. The dynamic quantification of the theory shows the non-secured time for act of terrorism which is considered for the non-secured condition against the risk of theft in nuclear material. For a realistic consideration, the meta-theoretical framework for modeling is performed for situations where beliefs, attributes or behaviors of an individual are influenced by those of others.

  8. The measurement of chemical persistence in the field by benchmarking : Theory and Experiment

    OpenAIRE

    Zou, Hongyan

    2015-01-01

    Persistence is one of the core criteria in chemical exposure and hazard assessment. It is often defined as the half-life for the removal of a chemical from a specified environment by transformation. Chemicals with long transformation half-lives may pose high risks for wildlife or humans and be subject to long-range transport to remote areas. It is challenging to measure persistence directly in the field in view of the complexity of the natural environment and spatial and temporal variability ...

  9. The Utility of Vulnerability and Social Capital Theories in Studying the Impact of Hurricane Katrina on the Elderly

    Science.gov (United States)

    Durant, Thomas J., Jr.

    2011-01-01

    The definition of a disaster is followed by an explanation of vulnerability and social capital theories. The importance of using a sound theoretical framework and the utility and efficacy of vulnerability and social capital theories in studying the impact of natural disasters on the elderly population are emphasized and discussed. The conclusion…

  10. Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) TRACI version 2.1 User’s Guide

    Science.gov (United States)

    TRACI 2.1 (the Tool for the Reduction and Assessment of Chemical and other environmental Impacts) has been developed for sustainability metrics, life cycle impact assessment, industrial ecology, and process design impact assessment for developing increasingly sustainable products...

  11. Positron-impact ionization of highly charged ions in lowest-order QED theory

    International Nuclear Information System (INIS)

    Lowest-order QED theory using distorted-wave states is applied to the calculation of positron-impact ionization cross sections for highly charged atomic ions. Electron and positron ionization cross sections for atomic ions are predicted to differ by substantial amounts in the threshold region. For highly charged ions like U90+, the smaller positron ionization cross section is more strongly affected by transverse photon interactions than the corresponding electron ionization cross section. At twice the threshold for U90+ ionization, the annihilation terms are found to reduce the positron cross section by about 12%

  12. Impact of environmentally based chemical hardness on uranium speciation and toxicity in six aquatic species.

    Science.gov (United States)

    Goulet, Richard R; Thompson, Patsy A; Serben, Kerrie C; Eickhoff, Curtis V

    2015-03-01

    Treated effluent discharge from uranium (U) mines and mills elevates the concentrations of U, calcium (Ca), magnesium (Mg), and sulfate (SO4 (2-) ) above natural levels in receiving waters. Many investigations on the effect of hardness on U toxicity have been experiments on the combined effects of changes in hardness, pH, and alkalinity, which do not represent water chemistry downstream of U mines and mills. Therefore, more toxicity studies with water chemistry encountered downstream of U mines and mills are necessary to support predictive assessments of impacts of U discharge to the environment. Acute and chronic U toxicity laboratory bioassays were realized with 6 freshwater species in waters of low alkalinity, circumneutral pH, and a range of chemical hardness as found in field samples collected downstream of U mines and mills. In laboratory-tested waters, speciation calculations suggested that free uranyl ion concentrations remained constant despite increasing chemical hardness. When hardness increased while pH remained circumneutral and alkalinity low, U toxicity decreased only to Hyalella azteca and Pseudokirchneriella subcapitata. Also, Ca and Mg did not compete with U for the same uptake sites. The present study confirms that the majority of studies concluding that hardness affected U toxicity were in fact studies in which alkalinity and pH were the stronger influence. The results thus confirm that studies predicting impacts of U downstream of mines and mills should not consider chemical hardness. Environ Toxicol Chem 2015;34:562-574. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of SETAC.

  13. Radioactive and hazardous chemical wastes. Impact on man and his environment

    International Nuclear Information System (INIS)

    The main objective of the various safety measures in all fields of human activities is to prevent deleterious effects of various agents on human health. Preventive health and safety measures therefore play an important role in achieving the main goal of the World Health Organization (WHO): 'Health for all by the year 2000'. The present WHO programme on environmental health emphasizes the prevention of chemical hazards as one of the most important environmental factors affecting human health. At the same time, protection from physical factors, including radiological protection, is part of this programme. Therefore, WHO compares health detriments from both physical and chemical agents. The paper describes the hazardous waste problems of great concern in industrialized countries. For instance, the Commission of the European Communities countries produce about 2x109 tonnes of waste per year, a rate which grows by 2 to 3% annually. This poses serious problems of pollution, particularly where the toxic ingredients do not decay. Special attention will also be given to the safe handling of high-level radioactive waste from the peaceful use of nuclear technology. These wastes have to be stored in safe storage facilities, or be disposed of without causing damage to man and his environment. The international measures to contain and control these wastes are described, including the activities of WHO within the Global Environmental Monitoring System and Regional Sea programmes of the United Nations Environment Programme. Guidelines and methodologies for the management of hazardous chemical and radioactive wastes are being developed through WHO to assist national authorities in this task. The paper pays special attention to a comparative assessment of environmental and public health impacts of toxic chemical and radioactive wastes. (author)

  14. Physico-chemical properties and cytotoxic effects of sugar-based surfactants: Impact of structural variations.

    Science.gov (United States)

    Lu, Biao; Vayssade, Muriel; Miao, Yong; Chagnault, Vincent; Grand, Eric; Wadouachi, Anne; Postel, Denis; Drelich, Audrey; Egles, Christophe; Pezron, Isabelle

    2016-09-01

    Surfactants derived from the biorefinery process can present interesting surface-active properties, low cytotoxicity, high biocompatibility and biodegradability. They are therefore considered as potential sustainable substitutes to currently used petroleum-based surfactants. To better understand and anticipate their performances, structure-property relationships need to be carefully investigated. For this reason, we applied a multidisciplinary approach to systematically explore the effect of subtle structural variations on both physico-chemical properties and biological effects. Four sugar-based surfactants, each with an eight carbon alkyl chain bound to a glucose or maltose head group by an amide linkage, were synthesized and evaluated together along with two commercially available standard surfactants. Physico-chemical properties including solubility, Krafft point, surface-tension lowering and critical micellar concentration (CMC) in water and biological medium were explored. Cytotoxicity evaluation by measuring proliferation index and metabolic activity against dermal fibroblasts showed that all surfactants studied may induce cell death at low concentrations (below their CMC). Results revealed significant differences in both physico-chemical properties and cytotoxic effects depending on molecule structural features, such as the position of the linkage on the sugar head-group, or the orientation of the amide linkage. Furthermore, the cytotoxic response increased with the reduction of surfactant CMC. This study underscores the relevance of a methodical and multidisciplinary approach that enables the consideration of surfactant solution properties when applied to biological materials. Overall, our results will contribute to a better understanding of the concomitant impact of surfactant structure at physico-chemical and biological levels. PMID:27137806

  15. Polar organic chemical integrative samplers for pesticides monitoring: impacts of field exposure conditions.

    Science.gov (United States)

    Lissalde, Sophie; Mazzella, Nicolas; Mazellier, Patrick

    2014-08-01

    This study focuses on how Polar Organic Chemical Integrative Samplers (POCIS) work in real environmental conditions. A selection of 23 polar pesticides and 8 metabolites were investigated by exposure of triplicates of integrative samplers in two rivers in France for successive 14-day periods. The pesticides and metabolites were trapped not only in Oasis HLB sorbent but also in the polyethersulfone (PES) membrane of the POCIS. The distribution of pesticides depended on the molecular structure. The use of the Performance Reference Compound (PRC) is also discussed here. The impact of some environmental parameters and exposure setup on the transfer of pesticides in POCIS sorbent was studied: river flow rate, biofouling on membranes, sampler holding design and position in the stream. Results show a significant impact of river flow velocity on PRC desorption, especially for values higher than 4 cm·s(-1). Some fouling was observed on the PES membrane which could potentially have an impact on molecule accumulation in the POCIS. Finally, the positioning of the sampler in the river did not have significant effects on pesticide accumulation, when perpendicular exposures were used (sampler positioning in front of the water flow). The POCIS with PRC correction seems to be a suitable tool for estimating time-weighted average (TWA) concentrations, for all the molecules except for one of the nine pesticides analyzed in these two French rivers.

  16. 78 FR 75910 - Impact of the Implementation of the Chemical Weapons Convention (CWC) on Legitimate Commercial...

    Science.gov (United States)

    2013-12-13

    ... Convention (CWC) on Legitimate Commercial Chemical, Biotechnology, and Pharmaceutical Activities Involving... Chemical Weapons Convention (CWC), through the Chemical Weapons Convention Implementation Act (CWCIA) and the Chemical Weapons Convention Regulations (CWCR), has had on commercial activities...

  17. Capabilities and Limitations of an Association Theory for Chemicals in Liquid or Supercritical Solvents

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios

    2012-01-01

    The cubic-plus-association (CPA) model is an equation of state (EoS) that combines the Soave–Redlich–Kwong (SRK) equation with the association term from Wertheim’s theory as used in statistical associating fluid theory (SAFT). In the form used here, the CPA EoS does not include separate terms....... The capabilities of the model are illustrated in the first two case studies: the phase behavior of mixtures used in the oxidation of 2-octanol in supercritical CO2 and the investigation of systems containing acetone, methanol, water, chloroform, and methyl acetate. In each case, both correlations of vapor...

  18. Mantle convection and plate tectonics: toward an integrated physical and chemical theory

    Science.gov (United States)

    Tackley

    2000-06-16

    Plate tectonics and convection of the solid, rocky mantle are responsible for transporting heat out of Earth. However, the physics of plate tectonics is poorly understood; other planets do not exhibit it. Recent seismic evidence for convection and mixing throughout the mantle seems at odds with the chemical composition of erupted magmas requiring the presence of several chemically distinct reservoirs within the mantle. There has been rapid progress on these two problems, with the emergence of the first self-consistent models of plate tectonics and mantle convection, along with new geochemical models that may be consistent with seismic and dynamical constraints on mantle structure.

  19. Modeling and simulation of chemically stimulated hydrogel layers using the multifield theory

    Science.gov (United States)

    Sobczyk, Martin; Wallmersperger, Thomas

    2016-04-01

    Polyelectrolyte hydrogels are ionic gels with viscoelastic properties. They are able to reversibly swell and deswell in response to different external stimuli. In the present work stacked layers of hydrogels - also referred to as hydrogel layers - under chemical stimulation are numerically investigated. For this, a set of coupled partial differential equations describing the chemical, the electrical and the mechanical field is solved by using the finite element method. The swelling behavior of the hydrogel layers - obtained by a novel approach for the osmotic pressure - is in excellent agreement with other investigations available in the literature.

  20. Ethical implications of democratic theory for U.S. public participation in environmental impact assessment

    International Nuclear Information System (INIS)

    Traditional mechanisms for public participation in environmental impact assessment under U.S. federal law have been criticized as ineffective and unable to resolve conflict. As these mechanisms are modified and new approaches developed, we argue that participation should be designed and evaluated not only on practical grounds of cost-effectiveness and efficiency, but also on ethical grounds based on democratic ideals. In this paper, we review and synthesize modern democratic theory to develop and justify four ethical principles for public participation: equal opportunity to participate, equal access to information, genuine deliberation, and shared commitment. We then explore several tensions that are inherent in applying these ethical principles to public participation in EIA. We next examine traditional NEPA processes and newer collaborative approaches in light of these principles. Finally, we explore the circumstances that argue for more in-depth participatory processes. While improved EIA participatory processes do not guarantee improved outcomes in environmental management, processes informed by these four ethical principles derived from democratic theory may lead to increased public engagement and satisfaction with government agency decisions. - Highlights: ► Four ethical principles based on democratic theory for public participation in EIA. ► NEPA and collaboration offer different strengths in meeting these principles. ► We explore tensions inherent in applying these principles. ► Improved participatory processes may improve public acceptance of agency decisions.

  1. Explaining the black-white gap in cognitive test scores: Toward a theory of adverse impact.

    Science.gov (United States)

    Cottrell, Jonathan M; Newman, Daniel A; Roisman, Glenn I

    2015-11-01

    In understanding the causes of adverse impact, a key parameter is the Black-White difference in cognitive test scores. To advance theory on why Black-White cognitive ability/knowledge test score gaps exist, and on how these gaps develop over time, the current article proposes an inductive explanatory model derived from past empirical findings. According to this theoretical model, Black-White group mean differences in cognitive test scores arise from the following racially disparate conditions: family income, maternal education, maternal verbal ability/knowledge, learning materials in the home, parenting factors (maternal sensitivity, maternal warmth and acceptance, and safe physical environment), child birth order, and child birth weight. Results from a 5-wave longitudinal growth model estimated on children in the NICHD Study of Early Child Care and Youth Development from ages 4 through 15 years show significant Black-White cognitive test score gaps throughout early development that did not grow significantly over time (i.e., significant intercept differences, but not slope differences). Importantly, the racially disparate conditions listed above can account for the relation between race and cognitive test scores. We propose a parsimonious 3-Step Model that explains how cognitive test score gaps arise, in which race relates to maternal disadvantage, which in turn relates to parenting factors, which in turn relate to cognitive test scores. This model and results offer to fill a need for theory on the etiology of the Black-White ethnic group gap in cognitive test scores, and attempt to address a missing link in the theory of adverse impact. PMID:25867168

  2. Do hormone-modulating chemicals impact on reproduction and development of wild amphibians?

    Science.gov (United States)

    Orton, Frances; Tyler, Charles R

    2015-11-01

    Globally, amphibians are undergoing a precipitous decline. At the last estimate in 2004, 32% of the approximately 6000 species were threatened with extinction and 43% were experiencing significant declines. These declines have been linked with a wide range of environmental pressures from habitat loss to climate change, disease and pollution. This review evaluates the evidence that endocrine-disrupting contaminants (EDCs) - pollutants that affect hormone systems - are impacting on wild amphibians and contributing to population declines. The review is limited to anurans (frogs and toads) as data for effects of EDCs on wild urodeles (salamanders, newts) or caecilians (limbless amphibians) are extremely limited. Evidence from laboratory studies has shown that a wide range of chemicals have the ability to alter hormone systems and affect reproductive development and function in anurans, but for the most part only at concentrations exceeding those normally found in natural environments. Exceptions can be found for exposures to the herbicide atrazine and polychlorinated biphenyls in leopard frogs (Rana pipiens) and perchlorate in African clawed frogs (Xenopus laevis). These contaminants induce feminising effects on the male gonads (including 'intersex' - oocytes within testes) at concentrations measured in some aquatic environments. The most extensive data for effects of an EDC in wild amphibian populations are for feminising effects of atrazine on male gonad development in regions across the USA. Even where strong evidence has been provided for feminising effects of EDCs, however, the possible impact of these effects on fertility and breeding outcome has not been established, making inference for effects on populations difficult. Laboratory studies have shown that various chemicals, including perchlorate, polychlorinated biphenyls and bromodiphenylethers, also act as endocrine disrupters through interfering with thyroid-dependent processes that are fundamental for

  3. Theory of Water Desalination by Porous Electrodes with Immobile Chemical Charge

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Hamelers, H.V.M.; Suss, M.E.

    2015-01-01

    In capacitive deionization (CDI), water is desalinated by storing ions in electrical double layers (EDLs) within the micropores of charged porous carbon electrodes. Recent experiments using chemically modified electrodes have shown differing, novel phenomena such as "inverted CDI," "enhanced CDI,

  4. Environmentally acceptable incineration of chlorinated chemical waste: review of theory and practice

    NARCIS (Netherlands)

    De Zeeuw, M.A.; Lemkowitz, S.M.

    1987-01-01

    Chlorinated hydrocarbons in the form of chemical waste, represent a threat to the environment and public health of the world. Their proper handling, removal and destruction is critical to long term safety. Increasingly strict government legislation is leading to an increase in the quantity of chlori

  5. Integrated assessment of the impact of chemical stressors on surface water ecosystems

    DEFF Research Database (Denmark)

    McKnight, Ursula S; Rasmussen, Jes J; Kronvang, Brian;

    2012-01-01

    The release of chemicals such as chlorinated solvents, pesticides and other xenobiotic organic compounds to streams, either from contaminated sites, accidental or direct application/release, is a significant threat to water resources. In this paper, different methods for evaluating the impacts......, an ecological model. The results showed that the hydromorphology, nutrients, biological oxygen demand and contaminants (pesticides and trichloroethylene from a contaminated site) originating from groundwater do not affect the good ecological status in the stream. In contrast, the evaluation by the novel SPEAR(pesticides......) index and TU indicated that the site is far from obtaining good ecological status - a direct contradiction to the ecological index currently in use in Denmark today - most likely due to stream sediment-bound pesticides arising from the spring spraying season. In order to generalise the findings...

  6. Combined use of meio- and macrobenthic indices to assess complex chemical impacts on a stream ecosystem

    Science.gov (United States)

    McKnight, Ursula S.; Sonne, Anne T.; Rasmussen, Jes J.; Traunspurger, Walter; Höss, Sebastian; Bjerg, Poul L.

    2016-04-01

    Ecosystem dynamics (e.g. temperature, inorganic nutrients) and properties (e.g. resilience, robustness), and ecological functions and services depend on the structure and diversity of biological communities, and the fluxes of energy and materials occurring within and across abiotic and biotic boundaries. The close interchange, i.e. multiple feedback loops, between hydrologic and biologic controls is also becoming increasingly evident. Holistic approaches are thus necessary for a robust understanding of ecosystem functioning and subsequent implementation of effective management practices across multiple spatial scales. Groundwater and surface water resources are under pressure from increasing global exploitation and anthropogenic impacts such as contamination by chemicals, leading to a severe degradation of essential ecological functions. Many of the environmental problems we face today have existed for decades; what has changed is our understanding of the key drivers, processes and impacts. The first reporting by European Member States (MS) on the status of their water bodies found that rivers and transitional waters were often in worse condition than lakes and coastal waters. This is not surprising considering that streams integrate all of the diverse stressors found within a catchment (e.g. contaminated sites; diffuse source pollution; water abstraction). The chemical status of a water body is relatively straightforward to assess, defined partly by environmental quality standards on priority substances and partly by additional regulations imposed by individual MS. However, the biological quality elements used for the classification of ecological status are only loosely defined, leaving MS free to develop their own assessment tools. Although useful for the individual MS, it impedes methodological standardization across different ecoregions, thus contributing to inconsistencies and data gaps across Europe. Moreover, despite the unambiguous importance of benthic

  7. Evolution of mechanical properties of silicate glasses: Impact of the chemical composition and effects of irradiation

    International Nuclear Information System (INIS)

    This thesis examines: (1) how the chemical composition changes the hardness, toughness, and stress corrosion cracking behavior in model pristine and (2) how external irradiation impact these properties. It is to be incorporated in the context of the storage of nuclear waste in borosilicate glass matrix, the structural integrity of which should be assessed. Eight simplified borosilicate glasses made of 3 oxides with modulated proportions (SiO2-B2O3-Na2O (SBN) have been selected and their hardness, toughness, and stress corrosion cracking behavior have been characterized prior and after irradiation. The comparative study of the non-irradiated SBN glasses provides the role played by the chemical composition. The sodium content is found to be the key parameter: As it increases, the glass plasticity increases, leading to changes in the mechanical response to strain. Hardness (Hv) and toughness (Kc) decrease since the flow under indenter increases. The analysis of the stress corrosion behavior evidences a clear shift of the SCC curves linked also to the glass plasticity. Four of the 8 simplified SBN glass systems highlight the influence of electron, light and heavy ions irradiations on the mechanical properties. Once again, the sodium content is a key parameter. It is found to inhibit the glass modification: Glasses with high sodium content are more stable. Ions irradiations highlight the predominant role of nuclear interaction in changing the glass properties. Finally, electronic interaction induced by helium and electron irradiation does not lead to the same structural/mechanical glasses variations. (author)

  8. Haematological malignancies in childhood in Croatia: Investigating the theories of depleted uranium, chemical plant damage and 'population mixing'

    International Nuclear Information System (INIS)

    Some of potential causes proposed to explain the reported increase of haematological malignancies in childhood during or after the war period in several countries include depleted uranium, chemical pollution and population mixing theory. The aim of this study was to define the population of Croatian children aged 0-14 years who were potentially exposed to each of those risks during the war and to investigate any possible association between the exposure and the incidence of haematological malignancies. The authors analyzed the data reported by the Cancer Registry of Croatia during the pre-war period (1986-1990), war period (1991-1995) and post-war period (1996-1999). In the group of 10 counties potentially exposed to depleted uranium and two counties where chemical war damage occurred, no significant difference in incidence of the studied haematological malignancies was noted in comparison to pre-war period. The incidence of lymphatic leukaemia significantly increased in four counties where population mixing had occurred during the war period, supporting the 'mixing theory'. In those counties, the incidence of Hodgkin's lymphoma decreased during and after the war. In Croatia as a whole, decreases in incidence of myeloid leukaemias during war and non-Hodgkin lymphoma after the war were noted

  9. Theory of water desalination by porous electrodes with fixed chemical charge

    OpenAIRE

    Biesheuvel, P. M.; Suss, M. E.; Hamelers, H.V.M.

    2015-01-01

    Water desalination by capacitive deionization (CDI) is performed via electrochemical cells consisting of two porous carbon electrodes. Upon transferring charge from one electrode to the other, ions are removed from the feedwater by electrosorption into electrical double layers (EDLs) within the micropores of the porous carbon. When using electrodes containing fixed chemical charge in the micropores, various counterintuitive observations have been made, such as "inverted CDI" where upon chargi...

  10. Impact of the post fire management in some soil chemical properties. First results.

    Science.gov (United States)

    Francos, Marcos; Pereira, Paulo; Alcañiz, Meritxell; Úbeda, Xavi

    2016-04-01

    Post-fire management after severe wildfires has impact on soil properties. In Mediterranean environments management of fire affected areas is a common practice. This intervention may change soil chemical properties of the soil such as major cations. The aim of this work is to study the impact of different types of forest management in soil extractable calcium, magnesium, sodium and potassium after a severe wildfire. The study area is located in Ódena (Catalonia, Spain). The wildfire occurred at July 27th of 2015 and burned 1235 ha. After the fire an experimental plot was designed 9 plots with 2x2 meters (4 square meters). The different managements were: a) clear-cuted area and wood removed, b) no treatment); and c) clear-cutted. The results of the first sampling showed significant differences among all treatments in extractable calcium, sodium and potassium. The amount of these extractable elements was high in clear-cutted treatment in comparison to the others. No differences were identified in extractable magnesium. Overall, in the immediate period after the fire, burned area management, changed the studied soil properties. We are currently studying the evolution of this soil properties in these plots with the time

  11. Legacy of a Chemical Factory Site: Contaminated Groundwater Impacts Stream Macroinvertebrates.

    Science.gov (United States)

    Rasmussen, Jes J; McKnight, Ursula S; Sonne, Anne Th; Wiberg-Larsen, Peter; Bjerg, Poul L

    2016-02-01

    Legislative and managing entities of EU member states face a comprehensive task because the chemical and ecological impacts of contaminated sites on surface waters must be assessed. The ecological assessment is further complicated by the low availability or, in some cases, absence of ecotoxicity data for many of the compounds occurring at contaminated sites. We studied the potential impact of a contaminated site, characterised by chlorinated solvents, sulfonamides, and barbiturates, on benthic macroinvertebrates in a receiving stream. Most of these compounds are characterised by low or unknown ecotoxicity, but they are continuously discharged into the stream by way of a long-lasting source generating long-term chronic exposure of the stream biota. Our results show that taxonomical density and diversity of especially sediment dwelling taxa were reduced by >50 % at the sampling sites situated in the primary inflow zone of the contaminated GW. Moreover, macroinvertebrate communities at these sampling sites could be distinguished from those at upstream control sites and sites situated along a downstream dilution gradient using multidimensional scaling. Importantly, macroinvertebrate indices currently used did not identify this impairment, thus underpinning an urgent need for developing suitable tools for the assessment of ecological effects of contaminated sites in streams.

  12. Social impact assessment in mining projects in Northern Finland: Comparing practice to theory

    Energy Technology Data Exchange (ETDEWEB)

    Suopajärvi, Leena, E-mail: leena.suopajarvi@ulapland.fi

    2013-09-15

    The paper discusses social impact assessments (SIA) for mining projects in light of the international principles and guidelines for such assessments and the academic literature in the field. The data consist of environmental impact assessment (EIA) programmes and reports for six mining projects that have started up in northern Finland in the 2000s. A first observation is that the role of the SIAs in the EIA programmes and reports studied was quite minor: measured in number of pages, the assessments account for three or four percent of the total. This study analyses the data collection, research methodology and conceptual premises used in the SIAs. It concludes that the assessments do not fully meet the high standards of the international principles and guidelines set out for them: for example, elderly men are over-represented in the data and no efforts were made to identify and bring to the fore vulnerable groups. Moreover, the reliability of the assessments is difficult to gauge, because the qualitative methods are not described and where quantitative methods were used, details such as non-response rates to questionnaires are not discussed. At the end of the paper, the SIAs are discussed in terms of Jürgen Habermas' theory of knowledge interests, with the conclusion that the assessments continue the empirical analytical tradition of the social sciences and exhibit a technical knowledge interest. -- Highlights: • Paper investigates social impact assessments in Finnish mining projects. • Role of social impact assessment is minor in whole EIA-process. • Mining SIAs give the voice for elderly men, vulnerable groups are not identified. • Assessment of SIAs is difficult because of lacking transparency in reporting. • SIAs belong to empirical analytical tradition with technical knowledge interest.

  13. Impact of Poultry Litter Cake, Cleanout, and Bedding following Chemical Amendments on Soil C and N Mineralization

    Directory of Open Access Journals (Sweden)

    Dexter B. Watts

    2012-01-01

    Full Text Available Poultry litter is a great alternative N source for crop production. However, recent poultry litter management changes, and increased chemical amendment use may impact its N availability. Thus, research was initiated to evaluate the effect that broiler cake and total cleanout litter amended with chemical additives have on C and N mineralization. A 35-day incubation study was carried out on a Hartsells fine sandy loam (fine-loamy, siliceous, subactive, thermic Typic Hapludults soil common to the USA Appalachian Plateau region. Three poultry litter components (broiler cake, total cleanout, and bedding material from a broiler house were evaluated and compared to a soil control. Chemical amendments lime (CaCO3, gypsum (CaSO4, aluminum sulfate (AlSO4, and ferrous sulfate (FeSO4 were added to the poultry litter components to determine their impact on C and N mineralization. Litter component additions increased soil C mineralization in the order of broiler cake > total cleanout > bedding > soil control. Although a greater concentration of organic C was observed in the bedding, broiler cake mineralized the most C, which can be attributed to differences in the C : N ratio between treatments. Chemical amendment in addition to the manured soil also impacted C mineralization, with AlSO4 generally decreasing mineralization. Nitrogen mineralization was also significantly affected by poultry litter component applications. Broiler cake addition increased N availability followed by total cleanout compared to soil control, while the bedding resulted in net N immobilization. Chemical amendments impacted N mineralization primarily in the broiler cake amended soil where all chemical amendments decreased mineralization compared to the no chemical amendment treatment. This short-term study (35-day incubation indicates that N availability to crops may be different depending on the poultry litter component used for fertilization and chemical amendment use which could

  14. Distribution of 90Sr in soil, rhizosphere and plants of the near impact zone of Krasnoyarsk mining-chemical plant

    International Nuclear Information System (INIS)

    This article is devoted to content of 90Sr in system 'soil - rhizosphere - plant' in a near impact zone of Krasnoyarsk mining-chemical plant. Also in the paper are shown a change of specific activity in environmental compartment at removal from Krasnoyarsk mining-chemical plant, accumulation of radiostrontium by rhizosphere, soil and roots of plants, its distribution in the top parts of plants. Also the comparison 90Sr and stable Sr in all studied objects was made.

  15. Wildfire Ash: Chemical Composition, Ash-Soil Interactions and Environmental Impacts

    Science.gov (United States)

    Brook, Anna; Hamzi, Seham; Wittenberg, Lea

    2015-04-01

    Of the five classical factors of soil formation, climate, parent material, topography, time, organisms, and recently recognized human activity, it is the latter factor which discretely includes fire and post-burn impact. However, it is considered that soil undergoing fire just experience a temporary removal of the top organic horizon, thus slightly modified and often labeled as 'temporarily disturbed' soil or soil 'under restoration/rehabilitation'. In fact the suggested seventh factor, post-burned produced ash, can act both dependently and independently of the other soil forming factors (Levin et al., 2013; Certini 2013). They are interdependent in cases where ash influences occur on time scales similar to 'natural' soil formation (Keesstra et ai., 2014) such as changes in vegetation. On the other hand, in post-fire areas a strong dependency is expected between soil-water retention mechanism, climate and topography. Wild-land fires exert many changes on the physical, chemical, mineralogical, biological, and morphological properties of soil that, in turn, affect the soil's hydrology and nutrient flux, modifying its ability to support vegetation and resist erosion. The ash produced by forest fires is a complex mixture composed of organic and inorganic particles characterized by vary physical-chemical and morphological properties. The importance of this study is straightforwardly related to the frequency and large-scales wildfires in Mediterranean region. In fact, wildfires are major environmental and land management concern in the world, where the number and severity of wildfires has increased during the past decades (Bodi, 2013). Certini (2013) assumed that cumulatively all of the vegetated land is burned in about 31 years annually affecting 330-430 Mha (over 3% of the Earth's surface) and wide range of land cover types worldwide including forests, peatlands, shrublands and grasslands. Whereas, the fire is identified as an important factor in soil formation, the

  16. Combined impact of lead, cadmium, polychlorinated biphenyls and non-chemical risk factors on blood pressure in NHANES

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Junenette L., E-mail: petersj@bu.edu; Patricia Fabian, M., E-mail: pfabian@bu.edu; Levy, Jonathan I., E-mail: jonlevy@bu.edu

    2014-07-15

    High blood pressure is associated with exposure to multiple chemical and non-chemical risk factors, but epidemiological analyses to date have not assessed the combined effects of both chemical and non-chemical stressors on human populations in the context of cumulative risk assessment. We developed a novel modeling approach to evaluate the combined impact of lead, cadmium, polychlorinated biphenyls (PCBs), and multiple non-chemical risk factors on four blood pressure measures using data for adults aged ≥20 years from the National Health and Nutrition Examination Survey (1999–2008). We developed predictive models for chemical and other stressors. Structural equation models were applied to account for complex associations among predictors of stressors as well as blood pressure. Models showed that blood lead, serum PCBs, and established non-chemical stressors were significantly associated with blood pressure. Lead was the chemical stressor most predictive of diastolic blood pressure and mean arterial pressure, while PCBs had a greater influence on systolic blood pressure and pulse pressure, and blood cadmium was not a significant predictor of blood pressure. The simultaneously fit exposure models explained 34%, 43% and 52% of the variance for lead, cadmium and PCBs, respectively. The structural equation models were developed using predictors available from public data streams (e.g., U.S. Census), which would allow the models to be applied to any U.S. population exposed to these multiple stressors in order to identify high risk subpopulations, direct intervention strategies, and inform public policy. - Highlights: • We evaluated joint impact of chemical and non-chemical stressors on blood pressure. • We built predictive models for lead, cadmium and polychlorinated biphenyls (PCBs). • Our approach allows joint evaluation of predictors from population-specific data. • Lead, PCBs and established non-chemical stressors were related to blood pressure.

  17. Combined impact of lead, cadmium, polychlorinated biphenyls and non-chemical risk factors on blood pressure in NHANES

    International Nuclear Information System (INIS)

    High blood pressure is associated with exposure to multiple chemical and non-chemical risk factors, but epidemiological analyses to date have not assessed the combined effects of both chemical and non-chemical stressors on human populations in the context of cumulative risk assessment. We developed a novel modeling approach to evaluate the combined impact of lead, cadmium, polychlorinated biphenyls (PCBs), and multiple non-chemical risk factors on four blood pressure measures using data for adults aged ≥20 years from the National Health and Nutrition Examination Survey (1999–2008). We developed predictive models for chemical and other stressors. Structural equation models were applied to account for complex associations among predictors of stressors as well as blood pressure. Models showed that blood lead, serum PCBs, and established non-chemical stressors were significantly associated with blood pressure. Lead was the chemical stressor most predictive of diastolic blood pressure and mean arterial pressure, while PCBs had a greater influence on systolic blood pressure and pulse pressure, and blood cadmium was not a significant predictor of blood pressure. The simultaneously fit exposure models explained 34%, 43% and 52% of the variance for lead, cadmium and PCBs, respectively. The structural equation models were developed using predictors available from public data streams (e.g., U.S. Census), which would allow the models to be applied to any U.S. population exposed to these multiple stressors in order to identify high risk subpopulations, direct intervention strategies, and inform public policy. - Highlights: • We evaluated joint impact of chemical and non-chemical stressors on blood pressure. • We built predictive models for lead, cadmium and polychlorinated biphenyls (PCBs). • Our approach allows joint evaluation of predictors from population-specific data. • Lead, PCBs and established non-chemical stressors were related to blood pressure.

  18. From Postmodernism to Postmodern Consumer. The Impact on the Consumption Theory

    Directory of Open Access Journals (Sweden)

    Dhouha JAZIRI BOUAGINA

    2014-06-01

    Full Text Available In most cases, the research focused on the discussion of Modernism-Postmodernism dichotomy without explicitly bringing to light the impact of this transition on the theory of consumption. Hence, the latter presents the objective of this literature gist overview. Drawing on Firat & Venkatech’s researches and many others, first, we attempt to shed lights on fundamental theoretical issues: What is the postmodern reflection? What are the main characteristics of modernism and postmodernism? The main critics explaining the transition from Modernism to Postmodernism? Second, the discussion moves toward highlighting the conditions and characteristics of the postmodern consumer. In this case, we aim to stress its relationship with the concept of the consumption lived experience. Hence, this literature review translates a progressive and critical theoretical analysis by highlighting the close relationship of the postmodernism with the emergence of the experiential approach.

  19. Impacts of biasing schemes in the one-loop integrated perturbation theory

    Science.gov (United States)

    Matsubara, Takahiko; Desjacques, Vincent

    2016-06-01

    The impact of biasing schemes on the clustering of tracers of the large-scale structure is analytically studied in the weakly nonlinear regime. For this purpose, we use the one-loop approximation of the integrated perturbation theory together with the renormalized bias functions of various, physically motivated Lagrangian bias schemes. These include the halo, peaks, and excursion set peaks model, for which we derive useful formulas for the evaluation of their renormalized bias functions. The shapes of the power spectra and correlation functions are affected by the different bias models at the level of a few percent on weakly nonlinear scales. These effects are studied quantitatively both in real and redshift space. The amplitude of the scale-dependent bias in the presence of primordial non-Gaussianity also depends on the details of the bias models. If left unaccounted for, these theoretical uncertainties could affect the robustness of the cosmological constraints extracted from galaxy clustering data.

  20. Impacts of biasing schemes in the one-loop integrated perturbation theory

    CERN Document Server

    Matsubara, Takahiko

    2016-01-01

    The impact of biasing schemes on the clustering of tracers of the large-scale structure is analytically studied in the weakly nonlinear regime. For this purpose, we use the one-loop approximation of the integrated perturbation theory (iPT) together with the renormalized bias functions of various, physically motivated Lagrangian bias schemes. These include the halo, peaks and excursion set peaks model, for which we derive useful formulae for the evaluation of their renormalized bias functions. The shapes of the power spectra and correlation functions are affected by the different bias models at the level of a few percent on weakly nonlinear scales. These effects are studied quantitatively both in real and redshift space. The amplitude of the scale-dependent bias in the presence of primordial non-Gaussianity also depends on the details of the bias models. If left unaccounted for, these theoretical uncertainties could affect the robustness of the cosmological constraints extracted from galaxy clustering data.

  1. Anthropogenic and impact spherules: Morphological similarity and chemical distinction – A case study from India and its implications

    Indian Academy of Sciences (India)

    Ambalika Niyogi; Jayanta K Pati; Suresh C Patel; Dipak Panda; Shiv K Patil

    2011-12-01

    This paper provides first report of silica-rich anthropogenic spherules of varying colour, shape, size, surface texture and chemical composition found in road-deposited sediments (RDS) of Allahabad city, Uttar Pradesh, India. Morphological details and lithophile elemental composition of the silica-rich spherules are compared to microtektites and impact spherules from India to demonstrate their striking morphological similarities and chemical variability. This study suggests the need to use spherule data carefully while assigning an impact origin to spherule-finds or spherule-bearing lithological horizons.

  2. Assessment of the impact of the European CO2 emissions trading scheme on the Portuguese chemical industry

    International Nuclear Information System (INIS)

    This paper describes an assessment of the impact of the enforcement of the European carbon dioxide (CO2) emissions trading scheme on the Portuguese chemical industry, based on cost structure, CO2 emissions, electricity consumption and allocated allowances data from a survey to four Portuguese representative units of the chemical industry sector, and considering scenarios that allow the estimation of increases on both direct and indirect production costs. These estimated cost increases were also compared with similar data from other European Industries, found in the references and with conclusions from simulation studies. Thus, it was possible to ascertain the impact of buying extra CO2 emission permits, which could be considered as limited. It was also found that this impact is somewhat lower than the impacts for other industrial sectors.

  3. Assessment of the impact of the European CO{sub 2} emissions trading scheme on the Portuguese chemical industry

    Energy Technology Data Exchange (ETDEWEB)

    Tomas, R.A.F. [Artenius Sines, Zona Industrial, 7520 Sines (Portugal); Ramoa Ribeiro, F.; Bordado, J.C.M. [Centro de Engenharia Quimica e Biologica, IBB-Instituto de Biotecnologia e Bioengenharia, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Santos, V.M.S. [Instituto Superior de Economia e Gestao, R. do Quelhas, 6, 1200-781 Lisboa (Portugal); Gomes, J.F.P. [Centro de Engenharia Quimica e Biologica, IBB-Instituto de Biotecnologia e Bioengenharia, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Departamento de Engenharia Quimica, Instituto Superior de Engenharia de Lisboa, R. Conselheiro Emidio Navarro 1949-014 Lisboa (Portugal)

    2010-01-15

    This paper describes an assessment of the impact of the enforcement of the European carbon dioxide (CO{sub 2}) emissions trading scheme on the Portuguese chemical industry, based on cost structure, CO{sub 2} emissions, electricity consumption and allocated allowances data from a survey to four Portuguese representative units of the chemical industry sector, and considering scenarios that allow the estimation of increases on both direct and indirect production costs. These estimated cost increases were also compared with similar data from other European Industries, found in the references and with conclusions from simulation studies. Thus, it was possible to ascertain the impact of buying extra CO{sub 2} emission permits, which could be considered as limited. It was also found that this impact is somewhat lower than the impacts for other industrial sectors. (author)

  4. An Evaluation of Financial Institutions: Impact on Consumption and Investment Using Panel Data and the Theory of Risk-Bearing.

    Science.gov (United States)

    Alem, Mauro; Townsend, Robert M

    2014-11-01

    The theory of the optimal allocation of risk and the Townsend Thai panel data on financial transactions are used to assess the impact of the major formal and informal financial institutions of an emerging market economy. We link financial institution assessment to the actual impact on clients, rather than ratios and non-performing loans. We derive both consumption and investment equations from a common core theory with both risk and productive activities. The empirical specification follows closely from this theory and allows both OLS and IV estimation. We thus quantify the consumption and investment smoothing impact of financial institutions on households including those running farms and small businesses. A government development bank (BAAC) is shown to be particularly helpful in smoothing consumption and investment, in no small part through credit, consistent with its own operating system, which embeds an implicit insurance operation. Commercial banks are smoothing investment, largely through formal savings accounts. Other institutions seem ineffective by these metrics.

  5. The dual impact of Freud's death and Freud's death instinct theory on the history of psychoanalysis.

    Science.gov (United States)

    Bergmann, Martin S

    2011-10-01

    Since I have ranged over a rather large territory in this presentation I will summarize my main points. I claim that the very way Freud created psychoanalysis made it impossible for it to continue to grow and develop as a unified movement after his death. Unlike other sciences, psychoanalysis had no way of differentiating its basic findings from what is yet to be discovered. I then reintroduced my differentiation between heretics, modifiers, and extenders, claiming that after Freud’s death there was less opportunity for heretics and more space for modifiers. I assigned a crucial role to the fact that Anna Freud did not succeed in expelling the Kleinians. In the second part of the paper I presented the view of those who made use of Freud’s death instinct theory and those who opposed it. Many analysts preferred to ignore dealing with it rather than state their opposition. My presentation was biased in favor of those who chose to work with the death instinct as a clinical reality,highlighting Ferenczi’s construction. I made the claim, so far as I know never made before, that Freud’s death instinct theory had a traumatic impact on the psychoanalytic movement because it greatly limited the belief in the curative power of our therapeutic work. After his announcement of the dual-instinct theory Freud withdrew his interest in psychoanalysis as a method of cure. By doing so he inflicted a narcissistic wound on psychoanalysis. I believe that the creativity of psychoanalysis will improve if we face this difficult chapter in our history.

  6. Theory of terahertz pumping of chemical environments in the condensed phase

    International Nuclear Information System (INIS)

    Newly emerged light-sources allow to generate fully synchronized, ultrashort and highly intense light pulses. With these light pulses, it is possible to initiate a process by a pump pulse and follow the dynamics via probe pulse in the femtosecond timescale. These pump-probe experiments play an important role for studying the chemical and biological processes in real time. Such techniques are also used to generate temperature-jump (T-jump) in ultrashort timescale to study the very fast kinetics of fundamental steps in chemical processes. Because of its biological and chemical relevance, T-jump experiments on liquid water have gained a lot of attention. Rather than acting as a passive environment, the dynamics of water during chemical and biological processes play a fundamental role in the solvation and stabilization of reaction intermediates. To target the O-H stretching mode of water with an infrared (IR) laser is a widely used mechanism to generate the T-jump in nanosecond to femtosecond timescales. With these techniques, T-jump has been limited only to few 10s of K so far. In this thesis, a new mechanism is investigated to generate T-jump up to few 100s of K in sub-ps timescale. The main portion of this thesis concentrates on the response of liquid water to sub-cycle THz pump pulses spectrally centered at 100 cm-1 (∝3 THz). The THz pump pulse with intensity of 5 x 1012 W/cm2 transfers a large amount of energy to inter- and intramolecular vibrations of water in sub-ps timescale. After the pump pulse, water reaches to a quasiequilibrium state, which is a gas-like hot liquid. The large energy gain in water causes significant structural modifications and vibrational shifting, which can be probed by timeresolved coherent x-ray scattering and time-resolved IR spectroscopy, respectively. Here, the interaction of THz pulse with water molecules is investigated from clusters to bulk water. We find it to be mainly described via the interaction of electric field with the

  7. Theory of terahertz pumping of chemical environments in the condensed phase

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Pankaj Kumar

    2015-12-15

    Newly emerged light-sources allow to generate fully synchronized, ultrashort and highly intense light pulses. With these light pulses, it is possible to initiate a process by a pump pulse and follow the dynamics via probe pulse in the femtosecond timescale. These pump-probe experiments play an important role for studying the chemical and biological processes in real time. Such techniques are also used to generate temperature-jump (T-jump) in ultrashort timescale to study the very fast kinetics of fundamental steps in chemical processes. Because of its biological and chemical relevance, T-jump experiments on liquid water have gained a lot of attention. Rather than acting as a passive environment, the dynamics of water during chemical and biological processes play a fundamental role in the solvation and stabilization of reaction intermediates. To target the O-H stretching mode of water with an infrared (IR) laser is a widely used mechanism to generate the T-jump in nanosecond to femtosecond timescales. With these techniques, T-jump has been limited only to few 10s of K so far. In this thesis, a new mechanism is investigated to generate T-jump up to few 100s of K in sub-ps timescale. The main portion of this thesis concentrates on the response of liquid water to sub-cycle THz pump pulses spectrally centered at 100 cm{sup -1} (∝3 THz). The THz pump pulse with intensity of 5 x 10{sup 12} W/cm{sup 2} transfers a large amount of energy to inter- and intramolecular vibrations of water in sub-ps timescale. After the pump pulse, water reaches to a quasiequilibrium state, which is a gas-like hot liquid. The large energy gain in water causes significant structural modifications and vibrational shifting, which can be probed by timeresolved coherent x-ray scattering and time-resolved IR spectroscopy, respectively. Here, the interaction of THz pulse with water molecules is investigated from clusters to bulk water. We find it to be mainly described via the interaction of

  8. An evaluation of the environmental impact assessment system in Vietnam: The gap between theory and practice

    International Nuclear Information System (INIS)

    Vietnam has one of the fastest growing economies in the world and has achieved significant socio-economic development in recent years. However this growth is placing increased pressure on an already depleted natural environment. Environmental impact assessment (EIA) is recognised by the Government and international organizations as an important tool in the management of the impacts of future development on the country's natural resource base. The Government's commitment to EIA has been demonstrated through the development and adoption of the Law on Environment Protection (Revised) in 2005 which sets out the requirements for EIA and which represents a major step in the development of a robust legislative framework for EIA in Vietnam. The Law on Environment Protection (Revised) 2005 has now been operational for several years and we have undertaken an evaluation of the resulting EIA system in Vietnam. We argue that while significant improvements have been achieved in the EIA policy framework, an important gap remains between EIA theory and practice. We contend that the basis of the current EIA legislation is strong and that future developments of the EIA system in Vietnam should focus on improving capacity of EIA practitioners rather than further substantial legislative change. Such improvements would allow the Vietnamese EIA system to emerge as an effective and efficient tool for environmental management in Vietnam and as a model EIA framework for other developing countries.

  9. Applications of the Information Theory to Problems of Molecular Electronic Structure and Chemical Reactivity

    Directory of Open Access Journals (Sweden)

    Roman F. Nalewajski

    2002-04-01

    Full Text Available Abstract: Recent studies on applications of the information theoretic concepts to molecular systems are reviewed. This survey covers the information theory basis of the Hirshfeld partitioning of molecular electron densities, its generalization to many electron probabilities, the local information distance analysis of molecular charge distributions, the charge transfer descriptors of the donor-acceptor reactive systems, the elements of a “thermodynamic” description of molecular charge displacements, both “vertical” (between molecular fragments for the fixed overall density and “horizontal” (involving different molecular densities, with the entropic representation description provided by the information theory. The average uncertainty measures of bond multiplicities in molecular “communication” systems are also briefly summarized. After an overview of alternative indicators of the information distance (entropy deficiency, missing information between probability distributions the properties of the “stockholder” densities, which minimize the entropy deficiency relative to the promolecule reference, are summarized. In particular, the surprisal analysis of molecular densities is advocated as an attractive information-theoretic tool in the electronic structure theory, supplementary to the familiar density difference diagrams. The subsystem information density equalization rules satisfied by the Hirshfeld molecular fragments are emphasized: the local values of alternative information distance densities of subsystems are equal to the corresponding global value, characterizing the molecule as a whole. These local measures of the information content are semi-quantitatively related to the molecular density difference function. In the density functional theory the effective external potentials of molecular fragments are defined, for which

  10. Recent Developments in the Theory of Mechanisms in Radiation Chemical Processes

    International Nuclear Information System (INIS)

    Recent developments in the mechanisms of radiation-initiated chemical reactions are reviewed. The role of ion molecule processes is reviewed, with particular reference to the radiation chemistry of methane. In this system, the existence of reactions of excited molecules, in addition to ionic processes is deduced. It is shown that, in the radiolysis of methane, unsaturated hydrocarbons play a considerable part in the mechanism of reaction. Developments in ionic polymerization and also polymerization under heterogenous conditions are reviewed. The importance of reactant purity, and also cleanliness of reaction vessels is discussed. The effect of an applied external potential in solid state polymerization is briefly reviewed. The importance of free-radical processes to radiation chemists is considered in the light of the Dow process for the production of ethyl bromide. (author)

  11. Computational organic chemistry: bridging theory and experiment in establishing the mechanisms of chemical reactions.

    Science.gov (United States)

    Cheng, Gui-Juan; Zhang, Xinhao; Chung, Lung Wa; Xu, Liping; Wu, Yun-Dong

    2015-02-11

    Understanding the mechanisms of chemical reactions, especially catalysis, has been an important and active area of computational organic chemistry, and close collaborations between experimentalists and theorists represent a growing trend. This Perspective provides examples of such productive collaborations. The understanding of various reaction mechanisms and the insight gained from these studies are emphasized. The applications of various experimental techniques in elucidation of reaction details as well as the development of various computational techniques to meet the demand of emerging synthetic methods, e.g., C-H activation, organocatalysis, and single electron transfer, are presented along with some conventional developments of mechanistic aspects. Examples of applications are selected to demonstrate the advantages and limitations of these techniques. Some challenges in the mechanistic studies and predictions of reactions are also analyzed.

  12. Biomass burning aerosol over the Amazon during SAMBBA: impact of chemical composition on radiative properties

    Science.gov (United States)

    Morgan, William; Allan, James; Flynn, Michael; Darbyshire, Eoghan; Hodgson, Amy; Liu, Dantong; O'shea, Sebastian; Bauguitte, Stephane; Szpek, Kate; Langridge, Justin; Johnson, Ben; Haywood, Jim; Longo, Karla; Artaxo, Paulo; Coe, Hugh

    2014-05-01

    Biomass burning represents one of the largest sources of particulate matter to the atmosphere, resulting in a significant perturbation to the Earth's radiative balance coupled with serious impacts on public health. Globally, biomass burning aerosols are thought to exert a small warming effect but with the uncertainty being 4 times greater than the central estimate. On regional scales, the impact is substantially greater, particularly in areas such as the Amazon Basin where large, intense and frequent burning occurs on an annual basis for several months. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to Black Carbon (BC) aerosol properties. Initial results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and a DMT Single Particle Soot Photometer (SP2). The physical, chemical and optical properties of the aerosols across the region will be characterized in order to establish the impact of biomass burning on regional air quality, weather and climate. The aircraft sampled a range of conditions including sampling of pristine Rainforest, fresh biomass burning plumes, regional haze and elevated biomass burning layers within the free troposphere. The aircraft sampled biomass burning aerosol across the southern Amazon in the states of Rondonia and Mato Grosso, as well as in a Cerrado (Savannah-like) region in Tocantins state. This presented a range of fire conditions, both in terms of their number, intensity, vegetation-type and their combustion efficiencies. Near-source sampling of fires in Rainforest environments suggested that smouldering combustion dominated, while flaming combustion dominated

  13. Chelating impact assessment of biological ad chemical chelates on metal extraction from contaminated soils

    International Nuclear Information System (INIS)

    Soil contamination is the result of uncontrolled waste dumping and poor practices by humans. Of all the pollutants heavy metals are of particular concern due to their atmospheric deposition, leaching capacity and non-biodegradability. Heavy metal containing effluent is discharged into the agricultural fields and water bodies. This results in the accumulation of heavy metals in soil and the crops grown on that soil. Studies have revealed detrimental impacts on soil fertility and the poor health of animals and humans. Phytoextraction is widely researched for remediation of heavy metal contaminated soil. To enhance the effect of phytoextraction heavy metals have to be available to the plants in soluble form. In this study the potential of different chelating agents was assessed in solubilizing the heavy metals making easy for plants to uptake them. For this purpose efficient chemical and biological chelating agent had to be identified. Along with that an optimum dose and application time for chemical chelating agent was determined. Ethylenediamine tetraacetic acid (EDTA), Diethylene triamine pentaacetic acid (DTPA), Nitriloacetic acid (NTA) were applied to the soil, containing Pb, Cr, Cu and Cd, at different concentrations and application time. Aspergillus niger and Aspergillus flavus were incubated in soil for different time periods. In correspondence with findings of the study, Pb and Cr were best solubilized by 5mM EDTA. For Cd and Cu 5mM DTPA carried out efficient chelation. NTA showed relatively inadequate solubilisation, although for Cr it performed equal to EDTA. A. niger and A. flavus instead of solubilizing adsorbed the metals in their biomass. Adsorption was mainly carried out by A. niger. (author)

  14. Theories of how the school environment impacts on student health: systematic review and synthesis.

    Science.gov (United States)

    Bonell, C P; Fletcher, A; Jamal, F; Wells, H; Harden, A; Murphy, S; Thomas, J

    2013-11-01

    Public-health interventions informed by theory can be more effective but complex interventions often use insufficiently complex theories. We systematically reviewed theories of how school environments influence health. We included 37 reports drawing on 24 theories. Narrative synthesis summarised and categorised theories. We then produced an integrated theory of school environment influences on student health. This integrated theory could inform complex interventions such as health promoting schools programmes. Using systematic reviews to develop theories of change might be useful for other types of 'complex' public-health interventions addressing risks at the individual and community levels.

  15. Global and Regional Impacts of HONO on the Chemical Composition of Clouds and Aerosols

    Science.gov (United States)

    Elshorbany, Y. F.; Crutzen, P. J.; Steil, B.; Pozzer, A.; Tost, H.; Lelieveld, J.

    2014-01-01

    Recently, realistic simulation of nitrous acid (HONO) based on the HONO / NOx ratio of 0.02 was found to have a significant impact on the global budgets of HOx (OH + HO2) and gas phase oxidation products in polluted regions, especially in winter when other photolytic sources are of minor importance. It has been reported that chemistry-transport models underestimate sulphate concentrations, mostly during winter. Here we show that simulating realistic HONO levels can significantly enhance aerosol sulphate (S(VI)) due to the increased formation of H2SO4. Even though in-cloud aqueous phase oxidation of dissolved SO2 (S(IV)) is the main source of S(VI), it appears that HONO related enhancement of H2O2 does not significantly affect sulphate because of the predominantly S(IV) limited conditions, except over eastern Asia. Nitrate is also increased via enhanced gaseous HNO3 formation and N2O5 hydrolysis on aerosol particles. Ammonium nitrate is enhanced in ammonia-rich regions but not under ammonia-limited conditions. Furthermore, particle number concentrations are also higher, accompanied by the transfer from hydrophobic to hydrophilic aerosol modes. This implies a significant impact on the particle lifetime and cloud nucleating properties. The HONO induced enhancements of all species studied are relatively strong in winter though negligible in summer. Simulating realistic HONO levels is found to improve the model measurement agreement of sulphate aerosols, most apparent over the US. Our results underscore the importance of HONO for the atmospheric oxidizing capacity and corroborate the central role of cloud chemical processing in S(IV) formation

  16. Nicolas Lémery (1645-1715 and his Physical-chemical Theory about Different Phenomena for Earth Sciences

    Directory of Open Access Journals (Sweden)

    Cándido Manuel GARCÍA CRUZ

    2016-06-01

    Full Text Available An unabridged translation of a work of Nicolas Lémery (1645–1715 is presented for the first time in Spanish, wherein this French chemist and apothecary attempts an explanation on physical and chemical basis of several significant phenomena in Earth Sciences, such as earthquakes, subterranean fires, hurricanes, lightning and thunder. This explanation had a common cause for all the aforementioned phenomena: the processes of mineral fermentation, in this case of sulfur and iron, as a heat source, within the corpuscular theory of matter and mechanistic philosophy, and likewise it represents an interesting contribution of the influence of chemistry on the incipient development of experimental geology at the dawn of the 18th Century. 

  17. Hydration of Krypton and Consideration of Clathrate Models of Hydrophobic Effects from the Perspective of Quasi-Chemical Theory

    CERN Document Server

    Ashbaugh, H S; Pratt, L R; Rempe, S B; Ashbaugh, Henry S.; Pratt, Lawrence R.; Rempe, Susan B.

    2002-01-01

    AIMD results on a liquid krypton-water system are compared to recent XAFS results for the radial hydration structure for a Kr atom in liquid water solution. The comparisons with the liquid solution results are satisfactory and significantly different from the radial distributions extracted from the data on the solid clathrate hydrate phase. The calculations also produce the coordination number distribution that can be examined for metastable coordination structures suggesting possibilities for clathrate-like organization; none are seen in these results. Clathrate pictures of hydrophobic hydration are discussed, as is the quasi-chemical theory that should provide a basis for clathrate pictures. Outer shell contributions are discussed and accurately estimated; they are positive and larger than the positive experimental hydration free energy of Kr(aq), implying that inner shell contributions must be negative. Clathrate-like inner shell coordination structures extracted from the simulation of the liquid, and then...

  18. Acid diffusion, standing waves, and information theory: a molecular-scale model of chemically amplified resist

    Science.gov (United States)

    Trefonas, Peter, III; Allen, Mary T.

    1992-06-01

    Shannon's information theory is adapted to analyze the photolithographic process, defining the mask pattern as the prior state. Definitions and constraints to the general theory are developed so that the information content at various stages of the lithographic process can be described. Its application is illustrated by exploring the information content within projected aerial images and resultant latent images. Next, a 3-dimensional molecular scale model of exposure, acid diffusion, and catalytic crosslinking in acid-hardened resists (AHR) is presented. In this model, initial positions of photogenerated acids are determined by probability functions generated from the aerial images and the local light intensity in the film. In order to simulate post-exposure baking processes, acids are diffused in a random walk manner, for which the catalytic chain length and the average distance between crosslinks can be set. Crosslink locations are defined in terms of the topologically minimized number required to link different chains. The size and location of polymer chains involved in a larger scale crosslinked network is established and related to polymer solubility. In this manner, the nature of the crosslinked latent image can be established. Good correlation with experimental data is found for the calculated percent insolubilization as a function of dose when the rms acid diffusion length is about 500 angstroms. Information analysis is applied in detail to the specific example of AHR chemistry. The information contained within the 3-D crosslinked latent image is explored as a function of exposure dose, catalytic chain length, average distance between crosslinks. Eopt (the exposure dose which optimizes the information contained within the latent image) was found to vary with catalytic chain length in a manner similar to that observed experimentally in a plot of E90 versus post-exposure bake time. Surprisingly, the information content of the crosslinked latent image remains

  19. Impact of poultry litter cake, cleanout, and bedding following chemical amendments on soil C and N mineralization

    Science.gov (United States)

    Poultry litter is a great alternative N source for crop production. However, recent poultry litter management changes and increased chemical amendment use may impact litter plant N availability. Thus, research was initiated to evaluate the effect that broiler house cake and total cleanout litter ame...

  20. A First Exploration of Health Impact Assessment of Chemical Exposure: Assigning Weights to Subclinical Effects Based on Animal Studies

    NARCIS (Netherlands)

    Burg, W. ter; Bokkers, B.G.H.; Kroese, E.D.; Schuur, A.G.

    2015-01-01

    ABSTRACT: Health impact assessments (HIA) have become an important tool for applying evidence-based policy. Recently, the concept of HIA has been introduced in the field of chemical substances. Two main issues are encountered, i.e., the focus of risk assessment is deriving safe levels and on first s

  1. Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil

    NARCIS (Netherlands)

    Sutton, N.B.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2014-01-01

    Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton’s reage

  2. X-rays in protoplanetary disks : Their impact on the thermal and chemical structure, a grid of models

    NARCIS (Netherlands)

    Aresu, G.; Kamp, I.; Meijerink, R.; Woitke, P.; Thi, W. F.; Spaans, M.

    2011-01-01

    X-rays impact protoplanetary disks hydrostatic, thermal and chemical structure. The range of efficiency of X-rays is explored using a grid modelling approach: different parameters affects the structure of the disk, this determines different contribution of the X-ray radiation to the chemistry and th

  3. Dempster-Shafer theory applied to regulatory decision process for selecting safer alternatives to toxic chemicals in consumer products.

    Science.gov (United States)

    Park, Sung Jin; Ogunseitan, Oladele A; Lejano, Raul P

    2014-01-01

    Regulatory agencies often face a dilemma when regulating chemicals in consumer products-namely, that of making decisions in the face of multiple, and sometimes conflicting, lines of evidence. We present an integrative approach for dealing with uncertainty and multiple pieces of evidence in toxics regulation. The integrative risk analytic framework is grounded in the Dempster-Shafer (D-S) theory that allows the analyst to combine multiple pieces of evidence and judgments from independent sources of information. We apply the integrative approach to the comparative risk assessment of bisphenol-A (BPA)-based polycarbonate and the functionally equivalent alternative, Eastman Tritan copolyester (ETC). Our results show that according to cumulative empirical evidence, the estimated probability of toxicity of BPA is 0.034, whereas the toxicity probability for ETC is 0.097. However, when we combine extant evidence with strength of confidence in the source (or expert judgment), we are guided by a richer interval measure, (Bel(t), Pl(t)). With the D-S derived measure, we arrive at various intervals for BPA, with the low-range estimate at (0.034, 0.250), and (0.097,0.688) for ETC. These new measures allow a reasonable basis for comparison and a justifiable procedure for decision making that takes advantage of multiple sources of evidence. Through the application of D-S theory to toxicity risk assessment, we show how a multiplicity of scientific evidence can be converted into a unified risk estimate, and how this information can be effectively used for comparative assessments to select potentially less toxic alternative chemicals.

  4. Early evaluation of potential environmental impacts of carbon nanotube synthesis by chemical vapor deposition.

    Science.gov (United States)

    Plata, Desirée L; Hart, A John; Reddy, Christopher M; Gschwend, Philip M

    2009-11-01

    The carbon nanotube (CNT) industry is expanding rapidly, yet little is known about the potential environmental impacts of CNT manufacture. Here, we evaluate the effluent composition of a representative multiwalled CNT synthesis by catalytic chemical vapor deposition (CVD) in order to provide data needed to design strategies for mitigating any unacceptable emissions. During thermal pretreatment of the reactant gases (ethene and H(2)), we found over 45 side-products were formed, including methane, volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). This finding suggests several environmental concerns with the existing process, including potential discharges of the potent greenhouse gas, methane (up to 1.7%), and toxic compounds such as benzene and 1,3-butadiene (up to 36000 ppmv). Extrapolating these laboratory-scale data to future industrial CNT production, we estimate that (1) contributions of atmospheric methane will be negligible compared to other existing sources and (2) VOC and PAH emissions may become important on local scales but will be small when compared to national industrial sources. As a first step toward reducing such unwanted emissions, we used continuous in situ measures of CNT length during growth and sought to identify which thermally generated compounds correlated with CNT growth rate. The results suggested that, in future CNT production approaches, key reaction intermediates could be delivered to the catalyst without thermal treatment. This would eliminate the most energetically expensive component of CVD synthesis (heating reactant gases), while reducing the formation of unintended byproducts. PMID:19924971

  5. Impact of endocrine-disrupting chemicals on reproductive function in zebrafish (Danio rerio).

    Science.gov (United States)

    Huang, Y; Wang, X L; Zhang, J W; Wu, K S

    2015-02-01

    The prevalence of endocrine-disrupting chemicals (EDCs) in the aquatic environment has been associated with the wide detection of alterations in the development and physiology of vertebrates. Zebrafish, as a model species, has been extensively used in toxicological research. In this review, we focus on recent published evidence of the harmful effects of EDCs on reproductive function in zebrafish, including skewed sex ratio, immature gonads, diminished sexual behaviour, decreased sperm count, reduced spawning and fertilization. These impairments mostly result from disruption to sex-steroid hormones induced by endocrine disruptors. We also discuss other effects of exposure to EDCs. In EDC exposure research, despite incomplete assessments of altered gonad histopathology and sexual behaviour, these present potential effective biomarkers or pathways for evaluating the reproductive function in zebrafish on EDC exposure. To date, the pernicious effects of some EDCs on the reproductive performance in laboratory zebrafish are well understood; however, similar alterations remain for further determination in wild-type fish and more kinds of EDCs. More studies should be performed under established scientific regulatory criteria to investigate the impact of EDCs on reproduction in zebrafish. Moreover, further research is required to explain the definite mechanism of sexual differentiation, which helps in understanding the shift of sexual phenotype with EDC exposure. PMID:25529055

  6. Global and regional impacts of HONO on the chemical composition of clouds and aerosols

    Science.gov (United States)

    Elshorban, Y. F.; Crutzen, P. J.; Steil, B.; Pozzer, A.; Tost, H.; Lelieveld, J.

    2013-09-01

    Nitrous acid (HONO) photolysis can significantly increase HOx (OH+HO2) radical formation, enhancing organic and inorganic oxidation products in polluted regions, especially during winter. It has been reported that chemistry-transport models underestimate sulphate concentrations, mostly during winter. Here we show that HONO can significantly enhance aerosol sulphate (S(VI)), mainly due to the increased formation of H2SO4. Even though in-cloud aqueous phase oxidation of dissolved SO2 (S(IV)) is the main source of S(VI), it appears that HONO related enhancement of H2O2 does not significantly affect sulphate because of the predominantly S(IV) limited conditions, except over eastern Asia. Nitrate is also increased via enhanced gaseous HNO3 formation and N2O5 hydrolysis on aerosol particles. Ammonium nitrate is enhanced in ammonia-rich regions but not under ammonia-limited conditions. Furthermore, particle number concentrations are also higher, accompanied by the transfer from hydrophobic to hydrophilic aerosol modes. This implies a significant impact on the particle lifetime and cloud nucleating properties. The HONO induced enhancements of all species studied are relatively strong in winter though negligible in summer. Simulating realistic HONO levels is found to improve the model-measurement agreement of sulphate aerosols, most apparent over the US. Our results underscore the importance of HONO for the atmospheric oxidizing capacity and the central role of cloud chemical processing in aerosol formation.

  7. The impact of the various chemical and physical factors on the degradation rate of bronopol.

    Science.gov (United States)

    Matczuk, M; Obarski, N; Mojski, M

    2012-10-01

    Bronopol (2-bromo-2-nitropropane-1,3-diol) is used as preservative in cosmetic industry. Its main role in commercial products consists in protection of the cosmetic composition stability by inhibiting the development of micro-organisms. Unfortunately, preservatives can also undergo the degradation processes. The aim of examinations was to prove that bronopol decomposes in aqueous solutions and storage conditions have a significance influence on its degradation rate. High-performance liquid chromatography method (methanol/water with hydrochloric acid 5:95 v/v) with spectrophotometric detection (210 nm) was used for examining the decomposition rate of bronopol. The impact of chemical (addition of cosmetics components: citric acid and/or sodium dodecylsulfate) and physical (elevated and ambient temperature, sunlight or ultraviolet radiation and air access) factors has been elaborated. Bronopol decomposes most rapidly (independently on the sample surrounding conditions) when it is in solution with sodium dodecylsulfate, the inverse dependence is observed in the presence of two compounds - citric acid and sodium dodecylsulfate. Additionally, the elevated temperature causes the acceleration of decomposition. Bronopol degradation by-products were also identified as methanol, formic acid, tris(hydroxymethyl)methane and 2-bromo-2-nitroethanol. PMID:22612984

  8. Teaching chemical reactions in the laboratory: linking theory and practice in teacher’s education and didactic action

    Directory of Open Access Journals (Sweden)

    Cleonice Puggian

    2013-03-01

    Full Text Available This paper presents the results of an investigation about chemistry teaching laboratory, describing the potential of a methodology that combines theoretical and hands on activities about chemical reactions. This proposal explores the curriculum content of high school chemistry, highlighting the teaching of chemical reactions, seeking the establishment of inter-relationships between the theoretical and practical knowledge inherent in the processes of school knowledge in Chemistry, challenging teachers to think about experimental activities not as an isolated moment in their class, but as an integral part of it. The methodology was qualitative in nature, adopting semi-structured interviews as instruments for data collection. The research was conducted with eight teachers of chemistry and seventy students from the second grade of high school from a technical school in Rio de Janeiro state. The results of this study indicate that this approach appears as an alternative to conducting laboratory experimental activities, contributing to a more formative and informative, less technical and fragmented teaching of chemistry in Basic Education. The research also shows that this approach supports teachers on their reflection of teaching practices, as well as on the planning and execution of experimental activities. We conclude that pedagogical proposals that articulate theory and practice are more effective in promoting the learning of high school students.

  9. APPLICATION OF CHEMICALLY ACCELERATED BIOTREATMENT TO REDUCE RISKIN OIL-IMPACTED SOILS

    Energy Technology Data Exchange (ETDEWEB)

    J.R. Paterek; W.W.Bogan; V. Trbovic; W. Sullivan

    2003-01-07

    The drilling and operation of gas/petroleum exploratory wells and the operations of natural gas and petroleum production wells generate a number of waste materials that are usually stored and/or processed at the drilling/operations site. Contaminated soils result from drilling operations, production operations, and pipeline breaks or leaks where crude oil and petroleum products are released into the surrounding soil or sediments. In many cases, intrinsic biochemical remediation of these contaminated soils is either not effective or is too slow to be an acceptable approach. This project targeted petroleum-impacted soil and other wastes, such as soil contaminated by: accidental release of petroleum and natural gas-associated organic wastes from pipelines or during transport of crude oil or natural gas; production wastes (such as produced waters, and/or fuels or product gas). Our research evaluated the process designated Chemically-Accelerated Biotreatment (CAB) that can be applied to remediate contaminated matrices, either on-site or in situ. The Gas Technology Institute (GTI) had previously developed a form of CAB for the remediation of hydrocarbons and metals at Manufactured Gas Plant (MGP) sites and this research project expanded its application into Exploration and Production (E&P) sites. The CAB treatment was developed in this project using risk-based endpoints, a.k.a. environmentally acceptable endpoints (EAE) as the treatment goal. This goal was evaluated, compared, and correlated to traditional analytical methods (Gas Chromatography (GC), High Precision Liquid Chromatography (HPLC), or Gas Chromatography-Mass Spectrometry (CGMS)). This project proved that CAB can be applied to remediate E&P contaminated soils to EAE, i.e. those concentrations of chemical contaminants in soil below which there is no adverse affect to human health or the environment. Conventional approaches to risk assessment to determine ''how clean is clean'' for soils

  10. The impact of chemical evolution on the observable properties of stellar populations

    CERN Document Server

    Tosi, M P

    2000-01-01

    The major effects of the chemical evolution of galaxies on the characteristics of their stellar populations are reviewed. A few examples of how the observed stellar properties derived from colour--magnitude diagrams can constrain chemical evolution models are given.

  11. Calculation of liquid-liquid equilibrium of aqueous two-phase systems using a chemical-theory-based excess Gibbs energy model

    Directory of Open Access Journals (Sweden)

    Pessôa Filho P. A.

    2004-01-01

    Full Text Available Mixtures containing compounds that undergo hydrogen bonding show large deviations from ideal behavior. These deviations can be accounted for through chemical theory, according to which the formation of a hydrogen bond can be treated as a chemical reaction. This chemical equilibrium needs to be taken into account when applying stability criteria and carrying out phase equilibrium calculations. In this work, we illustrate the application of the stability criteria to establish the conditions under which a liquid-phase split may occur and the subsequent calculation of liquid-liquid equilibrium using a chemical-theory-modified Flory-Huggins equation to describe the non ideality of aqueous two-phase systems composed of poly(ethylene glycol and dextran. The model was found to be able to correlate ternary liquid-liquid diagrams reasonably well by simple adjustment of the polymer-polymer binary interaction parameter.

  12. Chemical Species in the Vapor Phase of Hanford Double-Shell Tanks: Potential Impacts on Waste Tank Corrosion Processes

    Energy Technology Data Exchange (ETDEWEB)

    Felmy, Andrew R.; Qafoku, Odeta; Arey, Bruce W.; Boomer, Kayle D.

    2010-09-22

    The presence of corrosive and inhibiting chemicals on the tank walls in the vapor space, arising from the waste supernatant, dictate the type and degree of corrosion that occurs there. An understanding of how waste chemicals are transported to the walls and the affect on vapor species from changing supernatant chemistry (e.g., pH, etc.), are basic to the evaluation of risks and impacts of waste changes on vapor space corrosion (VSC). In order to address these issues the expert panel workshop on double-shell tank (DST) vapor space corrosion testing (RPP-RPT-31129) participants made several recommendations on the future data and modeling needs in the area of DST corrosion. In particular, the drying of vapor phase condensates or supernatants can form salt or other deposits at the carbon steel interface resulting in a chemical composition at the near surface substantially different from that observed directly in the condensates or the supernatants. As a result, over the past three years chemical modeling and experimental studies have been performed on DST supernatants and condensates to predict the changes in chemical composition that might occur as condensates or supernatants equilibrate with the vapor space species and dry at the carbon steel surface. The experimental studies included research on both the chemical changes that occurred as the supernatants dried as well as research on how these chemical changes impact the corrosion of tank steels. The chemical modeling and associated experimental studies were performed at the Pacific Northwest National Laboratory (PNNL) and the research on tank steel corrosion at the Savannah River National Laboratory (SRNL). This report presents a summary of the research conducted at PNNL with special emphasis on the most recent studies conducted in FY10. An overall summary of the project results as well as their broader implications for vapor space corrosion of the DST’s is given at the end of this report.

  13. The impact of soil uptake on the global distribution of molecular hydrogen: chemical transport model simulation

    Directory of Open Access Journals (Sweden)

    H. Yashiro

    2011-02-01

    Full Text Available The molecular hydrogen (H2 in the troposphere is highly influenced by the strength of H2 uptake by the terrestrial soil surface. The global distribution of H2 and its uptake by the soil are simulated by using a model called CHemical AGCM for Study of Environment and Radiative forcing (CHASER, which incorporates a 2-layered soil diffusion/uptake process component. The simulated distribution of deposition velocity over land reflects regional climate and has a global average of 3.3 × 10−2 cm s−1. In the region north of 30° N, the amount of soil uptake increases, particularly in the summer. However, the increase in the uptake becomes smaller in the winter season due to snow cover and a reduction in the biological activity at low temperatures. In the temperate and humid regions in the mid- and low-latitudes, the uptake is mostly influenced by the soil air ratio, which controls the gas diffusivity in the soil. In the semi-arid region, water stress and high temperature contribute to the reduction of biological activity, as well as to the seasonal variation in the deposition velocity. The comparison with the observations shows that the model reproduces both the distribution and seasonal variation of H2 relatively well. The global burden and tropospheric lifetime are 150 Tg and 2.0 yr, respectively. The seasonal variation of H2 in the northern high latitude is mainly controlled by the large seasonal change in soil uptake. In the Southern Hemisphere, the seasonal change in the net chemical production and inter-hemispheric transport are the dominant cause of the seasonal cycle. Large biomass burning impacts the magnitude of seasonal variation mainly in the tropics and subtropics. Both observation and model show large inter-annual variation, especially for the period 1997–1998, associated with the large biomass burning in tropics and northern high-latitudes. The soil uptake

  14. 40Ar/39Ar ages of lunar impact glasses: Relationships among Ar diffusivity, chemical composition, shape, and size

    Science.gov (United States)

    Zellner, N. E. B.; Delano, J. W.

    2015-07-01

    Lunar impact glasses, which are quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. This is because the Ar diffusion coefficient (at a constant temperature) is estimated to decrease by ∼3-4 orders of magnitude with an increasing fraction of non-bridging oxygens, X(NBO), over the compositional range of most lunar impact glasses with compositions from feldspathic to basaltic. Based on these relationships, lunar impact glasses with compositions and sizes sufficient to have retained ∼90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integrated temperatures of up to 290 K have been identified and are likely to have yielded reliable 40Ar/39Ar ages of formation. Additionally, ∼50% of the identified impact glass spheres have formation ages of ⩽500 Ma, while ∼75% of the identified lunar impact glass shards and spheres have ages of formation ⩽2000 Ma. Higher thermal stresses in lunar impact glasses quenched from hyperliquidus temperatures are considered the likely cause of poor survival of impact glass spheres, as well as the decreasing frequency of lunar impact glasses in general with increasing age. The observed age-frequency distribution of lunar impact glasses may reflect two processes: (i) diminished

  15. Long-range transport into the Arctic: Pathways, chemical impacts, and interannual variability

    Science.gov (United States)

    Duncan, B. N.; Liang, Q.

    2009-12-01

    We present a modeling and data analysis study of the variability and chemical impact of the import of anthropogenic pollution and biomass burning emissions into the Arctic. We apply principal component analysis (PCA) to a set of observed various trace gases and GEOS-5 tagged CO tracers to identify different air masses sampled by DC-8 aircraft during the NASA ARCTAS mission. The △O3/△CO ratio in individual air masses is calculated to understand the contribution of biomass burning and anthropogenic pollution to ozone in the Arctic troposphere. Anthropogenic plumes observed during both spring and summer show weak positive ozone productivity. Biomass burning plumes (mostly Siberian agricultural burning) observed during spring has a △O3/△CO ratio of 0.28 while the summertime boreal forest fires display a △O3/△CO ratio ~ 0, indicating very fresh plumes with little ozone production. We will analyze data from ARCTAS together with that from previous field missions, INTEX-A and INTEX-B, to further examine the interannual variability of the import of air masses into the Arctic. We will use a combination of observed trace gases and model age and source tracers in the NASA GEOS-5 GCM to assess the spatial/altitude variability of the transport pathways. We will correlate tracers of transport with a few well-known climate indices, i.e. the Arctic Oscillation and Pacific Decadal Oscillation, to understand the controlling dynamics of the interannual variability of import into the Arctic troposphere.

  16. Daily and hourly chemical impact of springtime transboundary aerosols on Japanese air quality

    Directory of Open Access Journals (Sweden)

    T. Moreno

    2012-09-01

    Full Text Available The regular eastward drift of transboundary aerosol intrusions from the Asian mainland into the NW Pacific region has a~pervasive impact on air quality in Japan, especially during springtime. Analysis of 24-h filter samples (ICP-AES and ICP-MS and hourly Streaker (PIXE samples of particulate matter collected continuously for six weeks reveal the chemistry of successive waves of natural mineral desert dust ("Kosa" and metalliferous sulphatic pollutants arriving in Western Japan during spring 2011. The main aerosol sources recognised by PMF analysis of Streaker data are mineral dust and fresh sea salt (both mostly in the coarser fraction PM2.5–10, As-bearing sulphatic aerosol (PM0.1–2.5, metalliferous sodic PM interpreted as aged, industrially contaminated marine aerosol, and ZnCu-bearing aerosols. Whereas mineral dust arrivals are typically highly transient, peaking over a few hours, sulphatic intrusions build up and decline more slowly, and are accompanied by notable rises in ambient concentrations of metallic trace elements such as Pb, As, Zn, Sn and Cd. The magnitude of the loss in regional air quality due to the spread and persistence of pollution from mainland Asia is especially clear when cleansing oceanic air advects westward across Japan, removing the continental influence and reducing concentrations of the more undesirable metalliferous pollutants by over 90%. Our new chemical database, especially the Streaker data, demonstrates the rapidly changing complexity of ambient air inhaled during these transboundary events, and implicates Chinese coal combustion as the main source of the anthropogenic aerosol component.

  17. Impacts of land use changes on physical and chemical soil properties in the Central Pyrenees

    Science.gov (United States)

    Nadal Romero, Estela; Hoitinga, Leo; Valdivielso, Sergio; Pérez Cardiel, Estela; Serrano Muela, Pili; Lasanta, Teodoro; Cammeraat, Erik

    2015-04-01

    Soils and vegetation tend to evolve jointly in relation to climate evolution and the impacts of human activity. Afforestation has been one of the main policies for environmental management of forest landscapes in Mediterranean areas. Afforestation has been based mainly on conifers because they are fast-growing species, and also because it was believed that this would lead to rapid restoration of soil properties and hydrological processes, and the formation of protective vegetation cover. This study analyses the effects of afforestation on physical and chemical soil properties. Specifically, we addressed this research question: (i) How do soil properties change after land abandonment? The 11 microsites considered were: Afforestation Pinus sylvestris (escarpment, terrace and close to the stem), Afforestation Pinus nigra (escarpment, terrace and close to the stem), natural shrubland, grasslands, bare lands, and undisturbed forest site (pine cover and close to the stem). An extensive single sampling was carried out in September 2014. We systematically collected 5 top soil samples (0-10 cm) and 3 deep soil samples (10-20 cm) per microsite (88 composite samples in total). These properties were analysed: (i) soil texture, (ii) bulk density, (iii) pH and electrical conductivity, (iv) total SOC, (v) Total Nitrogen, (vi) organic matter, (vii) CaCO3 and (viii) aggregate stability. Statistical tests have been applied to determine relationships between the different soil properties and are used to assess differences between different soil samples, land use areas and soil depths. Implications of reafforestation for soil development and environmental response are discussed. Acknowledgments This research was supported by a Marie Curie Intra-European Fellowship in the project "MED-AFFOREST" (PIEF-GA-2013-624974).

  18. Daily and hourly chemical impact of springtime transboundary aerosols on Japanese air quality

    Directory of Open Access Journals (Sweden)

    T. Moreno

    2013-02-01

    Full Text Available The regular eastward drift of transboundary aerosol intrusions from the Asian mainland into the NW Pacific region has a pervasive impact on air quality in Japan, especially during springtime. Analysis of 24-h filter samples with Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES and Mass Spectrometry (ICP-MS, and hourly Streaker with Particle Induced X-ray Emission (PIXE samples collected continuously for six weeks reveal the chemistry of successive waves of natural mineral desert dust ("Kosa" and metalliferous sulphatic pollutants arriving in western Japan during spring 2011. The main aerosol sources recognised by Positive Matrix Factorization (PMF analysis of Streaker data are mineral dust and fresh sea salt (both mostly in the coarser fraction PM2.5–10, As-bearing sulphatic aerosol (PM0.1–2.5, metalliferous sodic particulate matter (PM interpreted as aged, industrially contaminated marine aerosol, and ZnCu-bearing aerosols. Whereas mineral dust arrivals are typically highly transient, peaking over a few hours, sulphatic intrusions build up and decline more slowly, and are accompanied by notable rises in ambient concentrations of metallic trace elements such as Pb, As, Zn, Sn and Cd. The magnitude of the loss in regional air quality due to the spread and persistence of pollution from mainland Asia is especially clear when cleansing oceanic air advects westward across Japan, removing the continental influence and reducing concentrations of the undesirable metalliferous pollutants by over 90%. Our new chemical database, especially the Streaker data, demonstrates the rapidly changing complexity of ambient air inhaled during these transboundary events, and implicates Chinese coal combustion as the main source of the anthropogenic aerosol component.

  19. From mechanical to chemical impact of anchoring in seagrasses: The premises of anthropogenic patch generation in Posidonia oceanica meadows.

    Science.gov (United States)

    Abadie, Arnaud; Lejeune, Pierre; Pergent, Gérard; Gobert, Sylvie

    2016-08-15

    Intensive anchoring of leisure boats in seagrass meadows leads to mechanical damages. This anthropogenic impact creates bare mat patches that are not easily recolonized by the plant. Several tools are used to study human impacts on the structure of seagrass meadows but they are not able to assess the indirect and long term implication of mechanical destruction. We chose to investigate the possible changes in the substrate chemistry given contrasted boat impacts. Our observations show that hydrogen sulfide concentrations remain high at 15 and 20m depth (42.6μM and 18.8μM) several months after the highest period of anchoring during the summer. Moreover, our multidisciplinary study reveals that anchoring impacts of large boats at 15 and 20m depth can potentially change the seascape structure. By taking into account both structural and chemical assessments, different managing strategies must be applied for coastal areas under anthropogenic pressures. PMID:27289285

  20. Wildfire Ash: Chemical Composition, Ash-Soil Interactions and Environmental Impacts

    Science.gov (United States)

    Brook, Anna; Hamzi, Seham; Wittenberg, Lea

    2015-04-01

    Of the five classical factors of soil formation, climate, parent material, topography, time, organisms, and recently recognized human activity, it is the latter factor which discretely includes fire and post-burn impact. However, it is considered that soil undergoing fire just experience a temporary removal of the top organic horizon, thus slightly modified and often labeled as 'temporarily disturbed' soil or soil 'under restoration/rehabilitation'. In fact the suggested seventh factor, post-burned produced ash, can act both dependently and independently of the other soil forming factors (Levin et al., 2013; Certini 2013). They are interdependent in cases where ash influences occur on time scales similar to 'natural' soil formation (Keesstra et ai., 2014) such as changes in vegetation. On the other hand, in post-fire areas a strong dependency is expected between soil-water retention mechanism, climate and topography. Wild-land fires exert many changes on the physical, chemical, mineralogical, biological, and morphological properties of soil that, in turn, affect the soil's hydrology and nutrient flux, modifying its ability to support vegetation and resist erosion. The ash produced by forest fires is a complex mixture composed of organic and inorganic particles characterized by vary physical-chemical and morphological properties. The importance of this study is straightforwardly related to the frequency and large-scales wildfires in Mediterranean region. In fact, wildfires are major environmental and land management concern in the world, where the number and severity of wildfires has increased during the past decades (Bodi, 2013). Certini (2013) assumed that cumulatively all of the vegetated land is burned in about 31 years annually affecting 330-430 Mha (over 3% of the Earth's surface) and wide range of land cover types worldwide including forests, peatlands, shrublands and grasslands. Whereas, the fire is identified as an important factor in soil formation, the

  1. Application of density functional theory (DFT) to study the properties and degradation of natural estrogen hormones with chemical oxidizers

    Energy Technology Data Exchange (ETDEWEB)

    Rokhina, Ekaterina V.; Suri, Rominder P.S., E-mail: rominder.suri@temple.edu

    2012-02-15

    Estrone (E1), 17{beta}-estradiol (E2), estriol (E3), equilin (EQ) and 17{alpha}-estradiol (17{alpha}) estrogen hormones are released by humans and animals and have been detected in the environment and municipal wastewater treatment plants. The structural and electronic properties of natural hormone molecules are investigated by performing density functional theory calculations and used to predict their properties and chemical behavior. Quantitative structure property relationship (QSPR) approach is applied to correlate the estrogenicity associated with the natural estrogen hormones according to their molecular properties. The obtained relationship reveals the importance of the frontier molecular orbital energy in the interpretation of estrogenic activity of hormones, which is consistent with the previous research. Moreover, the obtained molecular descriptors also aid determination of the degradability of hormones, and to rationalize degradation pathways, with chemical oxidizers such as ozone and hydroxyl radical. Both types of interactions belong to the orbital-controlled reactions. The active sites determined by Fukui functions for the estrogen hormone molecules confirm the reaction pattern that initiates the attack of the aromatic ring for both ozone and hydroxyl radical. The reactive sites of the molecules are mapped with subsequent reaction intermediates and compared with experimental data obtained from the literature. - Highlights: Black-Right-Pointing-Pointer DFT methods described in this paper are suitable for predicting the degradation behavior of natural estrogen hormones. Black-Right-Pointing-Pointer Using QSAR, the estrogenicity of natural hormones was determined by DFT descriptors. Black-Right-Pointing-Pointer The sites of primary ozone and hydroxyl radical attack were predicted using DFT, and findings confirmed by experimental data.

  2. 40Ar/39Ar ages of lunar impact glasses: Relationships among Ar diffusivity, chemical composition, shape, and size

    CERN Document Server

    Zellner, N E B

    2015-01-01

    Lunar impact glasses, quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. Based on the relationships presented in this paper, lunar impact glasses with compositions and sizes sufficient to have retained 90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integra...

  3. Impact of NLTE on research of early chemical enrichment of the dwarf galaxies

    Science.gov (United States)

    Mashonkina, Lyudmila; Jablonka, Pascale; North, Pierre; Sitnova, Tatyana

    2016-08-01

    Based on high-resolution observed spectra, the non-local thermodynamic equilibrium (NLTE) line formation, and precise stellar atmosphere parameters, we present the first complete sample of dwarf spheroidal galaxies (dSphs) with accurate chemical abundances in the very metal-poor (VMP) regime. The obtained stellar elemental ratios are compared with chemical enrichment models, and we show that NLTE is a major step forward for studies of the dSph and the Milky Way (MW) chemical evolution.

  4. Impact of gamma irradiation on chemical composition of Melissa officinalis L.

    OpenAIRE

    Pereira, Eliana; Koike, Amanda; Antonio, Amilcar L.; Barros, Lillian; Ferreira, Isabel C. F. R.

    2014-01-01

    Food irradiation is increasingly recognized as an effective decontamination technique that ensures the chemical and organoleptic quality of the product. This decontamination method leads to a reduction in the application of chemical fumigants and preservatives, which are currently used by the food industry in order to provide higher safety for the consumer since it does not leave chemical residues in food. Melissa officinalis L. (commonly known as lemon balm) is used in several co...

  5. The Lattice Compatibility Theory LCT: Physical and Chemical Arguments from the Growth Behavior of Doped Compounds in terms of Bandgap Distortion and Magnetic Effects

    OpenAIRE

    Boubaker, K

    2013-01-01

    Physical and chemical arguments for the recently discussed materials-related Lattice Compatibility Theory are presented. The discussed arguments are based on some differences of Mn ions incorporation kinetics inside some compounds. These differences have been evaluated and quantified in terms of alteration of bandgap edges, magnetic patterns, and Faraday effect.

  6. Impact of chemically-modified tetracycline 3 on intertwined physiological, biochemical, and inflammatory networks in porcine sepsis/ARDS

    OpenAIRE

    Sadowsky, David; Nieman, Gary; Barclay, Derek; Mi, Qi; Zamora, Ruben; Constantine, Gregory; Golub, Lorne; Lee, Hsi-Ming; Roy, Shreyas; Gatto, Louis A; Vodovotz, Yoram

    2015-01-01

    Sepsis can lead to multiple organ dysfunction, including the Acute Respiratory Distress Syndrome (ARDS), due to intertwined, dynamic changes in inflammation and organ physiology. We have demonstrated the efficacy of Chemically-Modified Tetracycline 3 (CMT-3) at reducing inflammation and ameliorating pathophysiology in the setting of a clinically realistic porcine model of ARDS. Here, we sought to gain insights into the derangements that characterize sepsis/ARDS and the possible impact of CMT-...

  7. Chemically aged and mixed aerosols over the Central Atlantic Ocean - Potential impacts

    NARCIS (Netherlands)

    Astitha, M.; Kallos, G.; Spyrou, C.; O'Hirok, W.; Lelieveld, J.; Denier Gon, H.A.C. van der

    2010-01-01

    Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size dis

  8. Modelling the chemically aged and mixed aerosols over the eastern central Atlantic Ocean-potential impacts

    NARCIS (Netherlands)

    Astitha, M.; Kallos, G.; Spyrou, C.; O'Hirok, W.; Lelieveld, J.; Denier Gon, H.A.C. van der

    2010-01-01

    Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size dis

  9. Impact of sediment-seawater cation exchange on Himalayan chemical weathering fluxes

    Science.gov (United States)

    Lupker, Maarten; France-Lanord, Christian; Lartiges, Bruno

    2016-08-01

    Continental-scale chemical weathering budgets are commonly assessed based on the flux of dissolved elements carried by large rivers to the oceans. However, the interaction between sediments and seawater in estuaries can lead to additional cation exchange fluxes that have been very poorly constrained so far. We constrained the magnitude of cation exchange fluxes from the Ganga-Brahmaputra river system based on cation exchange capacity (CEC) measurements of riverine sediments. CEC values of sediments are variable throughout the river water column as a result of hydrological sorting of minerals with depth that control grain sizes and surface area. The average CEC of the integrated sediment load of the Ganga-Brahmaputra is estimated ca. 6.5 meq 100 g-1. The cationic charge of sediments in the river is dominated by bivalent ions Ca2+ (76 %) and Mg2+ (16 %) followed by monovalent K+ (6 %) and Na+ (2 %), and the relative proportion of these ions is constant among all samples and both rivers. Assuming a total exchange of exchangeable Ca2+ for marine Na+ yields a maximal additional Ca2+ flux of 28 × 109 mol yr-1 of calcium to the ocean, which represents an increase of ca. 6 % of the actual river dissolved Ca2+ flux. In the more likely event that only a fraction of the adsorbed riverine Ca2+ is exchanged, not only for marine Na+ but also Mg2+ and K+, estuarine cation exchange for the Ganga-Brahmaputra is responsible for an additional Ca2+ flux of 23 × 109 mol yr-1, while ca. 27 × 109 mol yr-1 of Na+, 8 × 109 mol yr-1 of Mg2+ and 4 × 109 mol yr-1 of K+ are re-absorbed in the estuaries. This represents an additional riverine Ca2+ flux to the ocean of 5 % compared to the measured dissolved flux. About 15 % of the dissolved Na+ flux, 8 % of the dissolved K+ flux and 4 % of the Mg2+ are reabsorbed by the sediments in the estuaries. The impact of estuarine sediment-seawater cation exchange appears to be limited when evaluated in the context of the long-term carbon cycle and

  10. Theories of managerial action and their impact on the conceptualisation of executive careers.

    OpenAIRE

    Alvarez, Jose L.

    1998-01-01

    In this paper I outline one of the developments in the social sciences and macro organizational theory that could be of special profit for academic work on careers. I argue that a theory of action perspective is timely because its assumptions fit extremely well with the heterogeneity and lability of today’s structures and the plurality and unpredictability they bring to careers. I suggest there are two basic potential contributions of theories of action to the field of careers. First, they en...

  11. Impact of Goal Orientation Theory on Social Capital: The Implications for Effective Team Cooperation in Uzbekistan Textile Industry

    OpenAIRE

    Akmal Hudaykulov; Xu Hongyi; Mostak Ahamed Galib

    2015-01-01

    The aim of the investigation was to identify and explain impact of performance orientation and learning orientation on the elements of social capital. A research model was based on goal orientation and social capital theory. A critical literature review on cooperation, social capital and goal orientation was conducted and the foundation for research was built. Ultimately cooperation within research and development teams in textile industry in Uzbekistan was assessed. Findings suggest there is...

  12. Meaning and impact of the notion of social contract in Rousseau and Kant. Scope and limitations in the democratic theory

    Directory of Open Access Journals (Sweden)

    Jefferson Jaramillo Marín

    2012-12-01

    Full Text Available This article reviews some of the similarities and differences about the political and legal foundation given to the notion of social contract by two modern thinkers: Jean Jacques Rousseau and Immanuel Kant. In the text, it is pointed the revolutionary part of the notion, from showing its principal meanings and impacts. Also, reflection is made on the scope and difficulties of the contractual proposal on the contemporary democratic theory.

  13. Impact Study of PMSG-Based Wind Power Penetration on Power System Transient Stability Using EEAC Theory

    OpenAIRE

    Zhongyi Liu; Chongru Liu; Gengyin Li; Yong Liu; Yilu Liu

    2015-01-01

    Wind turbines with direct-driven permanent magnet synchronous generators (PMSGs) are widely used in wind power generation. According to the dynamic characteristics of PMSGs, an impact analysis of PMSG-based wind power penetration on the transient stability of multi-machine power systems is carried out in this paper based on the theory of extended equal area criterion (EEAC). Considering the most severe PMSG integration situation, the changes in the system’s equivalent power-angle relationship...

  14. Chemical Production by Pulse-Laser Irradiation on Ices: Simulation of Impact Shock-Induced Chemistry on Icy Satellites

    Science.gov (United States)

    Nna-Mvondo, Delphine; Khare, B. N.; Ishihara, T.; McKay, C. P.; Cruikshank, D. P.; Borucki, W. J.

    2007-12-01

    Several icy satellites of the outer planets show a variety of impact cratering features. The effect of impact by extraterrestrial objects into the surface is commonly related to physical changes. Most of the research applied to impacts on ices has been developed to study and understand the cratering formation process and their physical, geophysical characteristics. Chemical changes and synthesis occurring on icy planetary surfaces are generally explained by the influence of UV photons and high-energy charged particles on ices. Nonetheless, impact process onto ices could be a source of local or global endogenic process and could be especially advantageous as an efficient energy source for driving interesting chemistry. Upon impact on icy surface, the kinetic energy of the impacting body is transferred to the ground liberating a great deal of stress energy which could initiate in situ aqueous melts of the ice, hydrolysis and other chemical reactions in the fracture zone beneath the crater. Here we present a novel experimental method to study the chemistry in planetary ices induced by impact shocks. Impact shocks were simulated in laboratory using a powerful pulsed laser (Q-switched Nd-YAG laser, 1064 nm). We have irradiated at 77K icy mixtures of H2O / CO2, H2O / Na2CO3, H2O / CH3OH and finally H2O / CH3OH / (NH4)2SO4. GC-MS and FTIR analyses show that hydrogen peroxide, carbon monoxide and methanol are formed in irradiated H2O / CO2 ices. Ice containing sodium carbonate generates under simulated impact CO and CO2 which are also produced in impacted H2O / CH3OH and H2O / CH3OH / (NH4)2SO4 ices. But, in both latter icy mixtures, methane and more complex molecules are also formed. We have detected acetone, methyl formate and dimethyl formal. Adding ammonium sulfate to ice containing methanol induces the production of N2O, HCN and CH3CN.

  15. Developing more positive attitudes towards mental health nursing in undergraduate students: part 2--The impact of theory and clinical experience.

    Science.gov (United States)

    Happell, B; Robins, A; Gough, K

    2008-09-01

    Previous research examining the impact of education on nursing students' attitudes towards mental health nursing as a career has highlighted clinical experience as the primary influencing factor and generally has not considered the impact of theory. The current study compared a cohort of second-year and a cohort of third-year nursing students from the same university. Second-year students had received more theory and clinical experience than their counterparts. Questionnaires were distributed to the total population of students before commencement of, and after completion of clinical placement. This paper examines students' perceived preparedness for and satisfaction with clinical experience, attitudes towards people with mental illness, and attitudes towards mental health nursing as a career option following the completion of differing amounts of theory and clinical experience. The results demonstrate some statistically significant differences with increased amounts of theory and clinical experience in the second-year cohort being positively influential. The findings suggest that an increased component of theoretical and clinical experience in psychiatric/mental health nursing is likely to produce more positive attitudes towards people with mental illness and psychiatric/mental health nursing. However, little difference in perceived preparedness for and satisfaction with clinical experience was noted between the two cohorts. PMID:18768004

  16. MEMIN: Chemical Modification of Projectile Spheres, Target Melts and Shocked Quartz in Hypervelocity Impact Experiments

    Science.gov (United States)

    Ebert, M.; Hecht, L.; Deutsch, A.; Kenkmann, T.

    2011-03-01

    We present results of hypervelocity cratering experiments using iron meteorite as projectile and a sandstone target. The ejecta show shock features (melting, PDFs, lechatelierite) and physical as well as chemical mixing between projectile and target.

  17. Brief Instrumental School-Based Mentoring for Middle School Students: Theory and Impact

    Science.gov (United States)

    McQuillin, Samuel D.; Lyons, Michael D.

    2016-01-01

    This study evaluated the efficacy of an intentionally brief school-based mentoring program. This academic goal-focused mentoring program was developed through a series of iterative randomized controlled trials, and is informed by research in social cognitive theory, cognitive dissonance theory, motivational interviewing, and research in academic…

  18. I can do that: the impact of implicit theories on leadership role model effectiveness.

    Science.gov (United States)

    Hoyt, Crystal L; Burnette, Jeni L; Innella, Audrey N

    2012-02-01

    This research investigates the role of implicit theories in influencing the effectiveness of successful role models in the leadership domain. Across two studies, the authors test the prediction that incremental theorists ("leaders are made") compared to entity theorists ("leaders are born") will respond more positively to being presented with a role model before undertaking a leadership task. In Study 1, measuring people's naturally occurring implicit theories of leadership, the authors showed that after being primed with a role model, incremental theorists reported greater leadership confidence and less anxious-depressed affect than entity theorists following the leadership task. In Study 2, the authors demonstrated the causal role of implicit theories by manipulating participants' theory of leadership ability. They replicated the findings from Study 1 and demonstrated that identification with the role model mediated the relationship between implicit theories and both confidence and affect. In addition, incremental theorists outperformed entity theorists on the leadership task. PMID:22143305

  19. Impact of environmental chemicals on key transcription regulators and correlation to toxicity end points within EPA's ToxCast program.

    Science.gov (United States)

    Martin, Matthew T; Dix, David J; Judson, Richard S; Kavlock, Robert J; Reif, David M; Richard, Ann M; Rotroff, Daniel M; Romanov, Sergei; Medvedev, Alexander; Poltoratskaya, Natalia; Gambarian, Maria; Moeser, Matt; Makarov, Sergei S; Houck, Keith A

    2010-03-15

    Exposure to environmental chemicals adds to the burden of disease in humans and wildlife to a degree that is difficult to estimate and, thus, mitigate. The ability to assess the impact of existing chemicals for which little to no toxicity data are available or to foresee such effects during early stages of chemical development and use, and before potential exposure occurs, is a pressing need. However, the capacity of the current toxicity evaluation approaches to meet this demand is limited by low throughput and high costs. In the context of EPA's ToxCast project, we have evaluated a novel cellular biosensor system (Factorial (1) ) that enables rapid, high-content assessment of a compound's impact on gene regulatory networks. The Factorial biosensors combined libraries of cis- and trans-regulated transcription factor reporter constructs with a highly homogeneous method of detection enabling simultaneous evaluation of multiplexed transcription factor activities. Here, we demonstrate the application of the technology toward determining bioactivity profiles by quantitatively evaluating the effects of 309 environmental chemicals on 25 nuclear receptors and 48 transcription factor response elements. We demonstrate coherent transcription factor activity across nuclear receptors and their response elements and that Nrf2 activity, a marker of oxidative stress, is highly correlated to the overall promiscuity of a chemical. Additionally, as part of the ToxCast program, we identify molecular targets that associate with in vivo end points and represent modes of action that can serve as potential toxicity pathway biomarkers and inputs for predictive modeling of in vivo toxicity. PMID:20143881

  20. Impact of Pinus Afforestation on Soil Chemical Attributes and Organic Matter in South Brazilian highlands

    Science.gov (United States)

    Pinheiro Dick, D.; Benvenuti Leite, S.; Dalmolin, R.; Almeida, H.; Knicker, H.; Martinazzo, R.

    2009-04-01

    The region known as Campos de Cima da Serra, located at 800 to 1400 m above sea level in the northeas of Rio Grande do Sul State, Brazil, is covered by a mosaic of natural grassland and Araucaria forest. Cattle raising, introduced by the first European settlers about 200 years ago, is the traditional economic activity in the region, occurring extensively and continuously on the natural pasture. In the last 30 years, while seeking for higher profits, local farmers have introduced agricultural crops and Pinus Taeda plantations in the original pasture lands. Pinus plantations are established in this area as dense monocultures and not as a sylvipastoral system, representing, thus, a severe threaten to the Campos' biodiversity. The soils are shallow, though very acidic (pH 4.2) and rich in exchangeable Al (28 to 47% of Al saturation), and present high contents of SOM in the surface layer (in general, higher than 4 %), which shows a low decomposition degree, as indicated by its high proportion of C-O alkyl groups (51 to 59 %). Considering that the biome sustainability of this region is being progressively affected by the change of land use and that systematic studies about exotic trees afforestation in that region are very scarce, our main objective was to investigate the impact of the introduction of Pinus on the SOM composition and chemical attributes of highland soils in 8 (Pi8) and 30 (Pi30) years old plantations, using as reference the original condition under native pasture (NP). In each studied Leptosol, soil samples were collected from three layers down to 15 cm ( 0-5 cm, 5-10 cm and 10-15 cm). Contents of exchangeable cations and of micronutrients and soil pH were determined. The SOM composition was investigated by means of elemental analyses, FTIR and fluorescence spectroscopy (three replicates). Prior to the spectroscopic analyses, samples were demineralized with 10% HF solution and organic matter loss was monitored. From the FTIR spectra, an aromaticity index

  1. Impact of Occupational Exposure to Chemicals in Life Cycle Assessment: A Novel Characterization Model Based on Measured Concentrations and Labor Hours.

    Science.gov (United States)

    Kijko, Gaël; Margni, Manuele; Partovi-Nia, Vahid; Doudrich, Greg; Jolliet, Olivier

    2015-07-21

    According to Lim et al., based on World Health Organization (WHO) data, hazardous chemicals in the workplace are responsible for over 370,000 premature deaths annually. Despite these high figures, life cycle impact assessment (LCIA) does not yet include a fully operational method to consider occupational impacts in its scope over the entire supply chain. This paper describes a novel approach to account for occupational exposure to chemicals by inhalation in LCA. It combines labor statistics and measured occupational concentrations of chemicals from the OSHA database to calculate operational LCIA characterization factors (i.e., intakes per hour worked and impact intensities for 19,069 organic chemical/sector combinations with confidence intervals across the entire U.S. manufacturing industry). For the seven chemicals that most contribute to the global impact, measured workplace concentrations range between 5 × 10(-4) and 3 × 10(3) mg/m(3). Carcinogenic impacts range over 4 orders of magnitude, from 1.3 × 10(-8) and up to 3.4 × 10(-4) DALY per blue-collar worker labor hour. The innovative approach set out in this paper assesses health impacts from occupational exposure to chemicals with population exposure to outdoor emissions, making it possible to integrate occupational exposure within LCIA. It broadens the LCIA scope to analyze hotspots and avoid impact shifting. PMID:26079305

  2. The impact of plant chemical diversity on plant-herbivore interactions at the community level.

    Science.gov (United States)

    Salazar, Diego; Jaramillo, Alejandra; Marquis, Robert J

    2016-08-01

    Understanding the role of diversity in ecosystem processes and species interactions is a central goal of ecology. For plant-herbivore interactions, it has been hypothesized that when plant species diversity is reduced, loss of plant biomass to herbivores increases. Although long-standing, this hypothesis has received mixed support. Increasing plant chemical diversity with increasing plant taxonomic diversity is likely to be important for plant-herbivore interactions at the community level, but the role of chemical diversity is unexplored. Here we assess the effect of volatile chemical diversity on patterns of herbivore damage in naturally occurring patches of Piper (Piperaceae) shrubs in a Costa Rican lowland wet forest. Volatile chemical diversity negatively affected total, specialist, and generalist herbivore damage. Furthermore, there were differences between the effects of high-volatility and low-volatility chemical diversity on herbivore damage. High-volatility diversity reduced specialist herbivory, while low-volatility diversity reduced generalist herbivory. Our data suggest that, although increased plant diversity is expected to reduce average herbivore damage, this pattern is likely mediated by the diversity of defensive compounds and general classes of anti-herbivore traits, as well as the degree of specialization of the herbivores attacking those plants. PMID:27129320

  3. Synthesis and Delivery of Peptides by Comet Impacts: A Possibility of Chemical Evolution in Enceladus's Subsurface Sea

    Science.gov (United States)

    Sugahara, H.; Mimura, K.

    2014-12-01

    Comet impacts are ubiquitous phenomena in the Solar system and the frequency was extremely high in the early history. Comets contain abundant organic materials, including bio-essential amino acids. Thus, it is proposed that comets have delivered organic molecules, which are important for the origins of life, to the outer solar bodies as well as the Earth. In the study, we conducted shock experiments on icy mixtures of amino acids (glycine and alanine), water ice, and forsterite at cryogenic condition (77 K), simulating comet impacts. The purpose of the study is to examine the effect of impact shock on amino acids in comets. We also focused on the oligomerization of amino acids to produce peptides. Peptides are important molecules for the origins of life, because they are building block of proteins and also act as catalysts to form other biomolecules. In the experiments, the starting mixture was kept frozen in a reaction capsule placed in liquid nitrogen (77K) and was impacted by a vertical propellant gun. The shock pressure range achieved in the experiments was 4.8-26.3 GPa. The results showed that amino acids were oligomerized into peptides up to tripeptides by impact shock at cryogenic condition. In addition, the yields of linear dipeptides were higher than those of cyclic diketopiperazines. These results are in contrast to the results of shock experiments to amino acid solutions at room temperature, which resulted in the synthesis of comparable amount of diketopiperazines to that of linear peptides (Blank et al., 2001). Thus, the cryogenic condition at impact shock would be a key to facilitate the formation of linear peptides. If we apply our results to the event of icy satellite formation, comet impacts should play an important role to supply linear peptides to the satellites. The shock-synthesized peptides would have been spread over the subsurface seas of the icy satellites (e.g. Enceladus) and might have been an important source for chemical evolution on the

  4. Dynamics, Miscibility, and Morphology in Polymer-Molecule Blends: The Impact of Chemical Functionality

    KAUST Repository

    Do, Khanh

    2015-10-22

    In the quest to improve the performance of organic bulk-heterojunction solar cells, many recent efforts have focused on developing molecular and polymer alternatives to commonly used fullerene acceptors. Here, molecular dynamics simulations are used to investigate polymer-molecule blends comprised of the polymer donor poly(3-hexylthiophene) (P3HT) with a series of acceptors based on trialkylsilylethynyl-substituted pentacene. A matrix of nine pentacene derivatives, consisting of systematic chemical variation both in the nature of the alkyl groups and electron-withdrawing moieties appended to the acene, is used to draw connections between the chemical structure of the acene acceptor and the nanoscale properties of the polymer-molecule blend. These connections include polymer and molecular diffusivity, donor-acceptor packing and interfacial (contact) area, and miscibility. The results point to the very significant role that seemingly modest changes in chemical structure play during the formation of polymer-molecule blend morphologies.

  5. Hydrogeo-chemical impacts of air sparging remediation on a semi-confined aquifer: evidences from field monitoring and modeling.

    Science.gov (United States)

    Fan, W; Yang, Y S; Lu, Y; Du, X Q; Zhang, G X

    2013-01-01

    Air sparging (AS) was explored for remediation of a petroleum contaminated semi-confined groundwater system in NE China. Physical, hydro-chemical and hydraulic behaviors in subsurface environment during AS were investigated with support of modeling to understand the hydrogeo-chemical impacts of AS on the aquifer. The responses of groundwater, dissolved oxygen and temperature indicated that the radius of influence of AS was up to 8-9 m, and a 3D boundary of the zone of influence (ZOI) was accordingly obtained with volume of 362 m(3). Water mounding unlike normal observations was featured by continuous up-lift and blocked dissipation. AS induced water displacement was calculated showing no obvious spreading of contaminant plume under this AS condition. Slug tests were employed before and after AS to reveal that the physical perturbation led to sharp increase in permeability and porosity. Modeling indicated that the regional groundwater flow field was not affected by AS except the physical perturbation in ZOI. Hydro-chemically increase of pH and Eh, and reduction of TDS, electrical conductivity and bicarbonate were observed in ZOI during AS. PHREEQC modeling inferred that these chemical phenomena were induced by the inorganic carbon transfer during air mixing.

  6. Towards validating use of self reported health (SRH) for community-based studies: Impact of environmental chemicals, sociodemographic variables, depression, and clinical indicators of health and nutrition

    Science.gov (United States)

    Environmental health impact assessment (HIA) studies, should consider social, behavioral, nutritional, dietary, environmental exposure and health risk factors at both the individual and community levels. Chemicals measured in blood or urine are often evaluated in relation to one ...

  7. APPLICATION OF CHEMICALLY ACCELERATED BIOTREATMENT TO REDUCE RISK IN OIL-IMPACTED SOILS

    Energy Technology Data Exchange (ETDEWEB)

    J.R. Paterek; W.W. Bogan; L.M. Lahner; V. Trbovic; E. Korach

    2001-05-01

    The overall program objective is to develop and evaluate integrated biological/physical/chemical co-treatment strategies for the remediation of wastes associated with the exploration and production of fossil energy. The specific objectives of this project are: chemical accelerated biotreatment (CAB) technology development for enhanced site remediation, application of the risk based analyses to define and support the rationale for environmental acceptable endpoints (EAE) for exploration and production wastes, and evaluate both the technological technologies in conjugation for effective remediation of hydrocarbon contaminated soils from E&P sites in the USA.

  8. Impact analysis of different chemical pre-treatments on colour of apple discs during drying process

    OpenAIRE

    Magdić, D.; Lukinac, Jasmina; Jokić, Stela; Čačić-Kenjerić, F.; Bilić, M.; Velić, D.

    2009-01-01

    The main purpose of this study was to compare colour changes of chemically pre-treated dried apple discs. Changes were observed by chromameter in L*a*b* colour model by using Minolta chromameter CR-400 and by image analysis system in RGB colour model. Apple discs variety "Gold Rush" were pre-treated and dried in laboratory tray drier at drying temperature 70 °C and at airflow velocity of 1.5 ms-1. Different chemical pre-treatments were applied on apple discs (dipping in 0.5% ascorbic acid sol...

  9. A path forward in the debate over health impacts of endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Zoeller, Robert T; Bergmann, Åke; Becher, Georg;

    2014-01-01

    and risk assessment reviewed the various aspects of the debate to identify the most significant areas of dispute and to propose a path forward. We identified four areas of debate. The first is about the definitions for terms such as "endocrine disrupting chemical", "adverse effects", and "endocrine system......Several recent publications reflect debate on the issue of "endocrine disrupting chemicals" (EDCs), indicating that two seemingly mutually exclusive perspectives are being articulated separately and independently. Considering this, a group of scientists with expertise in basic science, medicine...

  10. APPLICATION OF CHEMICALLY ACCELERATED BIOTREATMENT TO REDUCE RISK IN OIL-IMPACTED SOILS

    Energy Technology Data Exchange (ETDEWEB)

    J.R. Paterek; W.W. Bogan; L.M. Lahner; A. May

    2000-04-01

    The overall program objective is to develop and evaluate integrated biological/physical/chemical co-treatment strategies for the remediation of wastes associated with the exploration and production of fossil energy. The specific objectives of this project are: chemical accelerated biotreatment (CAB) technology development for enhanced site remediation, application of the risk based analyses to define and support the rationale for environmental acceptable endpoints (EAE) for exploration and production wastes, and evaluate both the technological technologies in conjugation for effective remediation of hydrocarbon contaminated soils from E&P sites in the USA.

  11. Olive oil pilot-production assisted by pulsed electric field: impact on extraction yield, chemical parameters and sensory properties.

    Science.gov (United States)

    Puértolas, Eduardo; Martínez de Marañón, Iñigo

    2015-01-15

    The impact of the use of pulsed electric field (PEF) technology on Arroniz olive oil production in terms of extraction yield and chemical and sensory quality has been studied at pilot scale in an industrial oil mill. The application of a PEF treatment (2 kV/cm; 11.25 kJ/kg) to the olive paste significantly increased the extraction yield by 13.3%, with respect to a control. Furthermore, olive oil obtained by PEF showed total phenolic content, total phytosterols and total tocopherols significantly higher than control (11.5%, 9.9% and 15.0%, respectively). The use of PEF had no negative effects on general chemical and sensory characteristics of the olive oil, maintaining the highest quality according to EU legal standards (EVOO; extra virgin olive oil). Therefore, PEF could be an appropriate technology to improve olive oil yield and produce EVOO enriched in human-health-related compounds, such as polyphenols, phytosterols and tocopherols.

  12. Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

    Science.gov (United States)

    Engling, G.; He, J.; Betha, R.; Balasubramanian, R.

    2014-08-01

    Biomass burning activities commonly occur in Southeast Asia (SEA), and are particularly intense in Indonesia during the dry seasons. The effect of biomass smoke emissions on air quality in the city state of Singapore was investigated during a haze episode in October 2006. Substantially increased levels of airborne particulate matter (PM) and associated chemical species were observed during the haze period. Specifically, the enhancement in the concentration of molecular tracers for biomass combustion such as levoglucosan by as much as two orders of magnitude and the diagnostic ratios of individual organic compounds indicated that biomass burning emissions caused a regional smoke haze episode due to their long-range transport by prevailing winds. With the aid of air mass backward trajectories and chemical mass balance modeling, large-scale forest and peat fires in Sumatra and Kalimantan were identified as the sources of the smoke aerosol, exerting a significant impact on air quality in downwind areas, such as Singapore.

  13. Assessing the regional impact of Indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

    Directory of Open Access Journals (Sweden)

    G. Engling

    2014-01-01

    Full Text Available Biomass burning activities commonly occur in Southeast Asia (SEA, and are particularly intense in Indonesia during dry seasons. The effect of biomass smoke emissions on air quality in the city state of Singapore was investigated during a haze episode in October 2006. Substantially increased levels of airborne particulate matter (PM and associated chemical species were observed during the haze period. Specifically, the enhancement in the concentration of molecular tracers for biomass combustion such as levoglucosan by as much as two orders of magnitude and diagnostic ratios of individual organic compounds indicated that biomass burning emissions caused a regional smoke haze episode due to their long-range transport by prevailing winds. With the aid of air mass back trajectories and chemical mass balance modeling, large-scale forest and peat fires in Sumatra and Kalimantan were identified as the sources of the smoke aerosol, exerting a significant impact on air quality in downwind areas, such as Singapore.

  14. The Impact of the South Asia High Bimodality on the Chemical Composition of the Upper Troposphere and Lower Stratosphere

    Institute of Scientific and Technical Information of China (English)

    YAN Ren-Chang; BIAN Jian-Chun; FAN Qiu-Jun

    2011-01-01

    The South Asia High (SAH) is the dominant feature of the circulation in the upper troposphere and lower stratosphere (UTLS) during the boreal summer, and the upper tropospheric anticyclonic circulation extends into the lower stratosphere. The preferred locations of the center of the SAH occur in two different regions, and the center can be located over the Iranian Plateau or over the Tibetan Plateau. This bimodality has an impact on the distribution of chemical constituents in the UTLS region. We analyzed water vapor (H20), carbon monoxide (CO), and ozone (03) data derived from the Aura Microwave Limb Sounder (MLS) and total column ozone data from the Ozone Monitoring Instrument (OMI). For the Iranian Plateau mode of the SAH, the tropospheric tracers exhibited a positive anomaly over the Iranian Plateau and a negative anomaly over the Tibetan Plateau, whereas the stratospheric tracer exhibited a negative and a positive anomaly over the Iranian Plateau and the Tibetan Plateau, respectively. For the Tibetan Plateau mode, however, the distribution of the anomaly was the reverse of that found for the chemical species in the UTLS region. Furthermore, the locations of the extrema within the anomaly seemed to differ across chemical species. The anomaly extrema for H20 occurred in the vicinity of the SAH ridgeline, whereas CO and O3 exhibited a northward shift of 4-8 degrees. These impacts of the variation in the SAH on the chemical constitutes in the UTLS region can be attributed in part to the dynamical structure delineated by the tropopause field and the temperature field at 100 hPa.

  15. Modeling of photolysis rates over Europe: impact on chemical gaseous species and aerosols

    Directory of Open Access Journals (Sweden)

    E. Real

    2010-07-01

    Full Text Available This paper evaluates the impact of photolysis rate calculation on European air composition and air quality monitoring. In particular, the impact of cloud parametrisation and the impact of aerosols on photolysis rates are analysed. Photolysis rates are simulated using the Fast-JX photolysis scheme and gas and aerosol concentrations over Europe are simulated with the regional model Polair3D of the Polyphemus platform. The photolysis scheme is first use to update the clear sky tabulation used in the previous Polair3D version. Important differences in photolysis rates are simulated, mainly due to updated cross-sections in the Fast-JX scheme. In the previous Polair3D version, clouds were taken into account by multiplying the clear-sky photolysis rates using a correction factor. In a second stage, the impact of clouds is taken into account more accurately by simulating them directly in the photolysis scheme. Differences in photolysis rates inside clouds are as high as differences between simulations with and without clouds. Outside clouds, the differences are small. The largest difference in gas concentrations is simulated for OH with a mean increase of its tropospheric burden of 4 to 5%.

    To take into account the impact of aerosols on photolysis rates, Polair3D and Fast-JX are coupled. Photolysis rates are updated every hour. Large impact on photolysis rates is observed at the ground, decreasing with altitude. The aerosol species that impact the most photolysis rates is dust especially in South Europe. Strong impact is also observed over anthropogenic emission regions (Paris, The Po and the Ruhr Valley where mainly nitrate and sulphate reduced the incoming radiation. Differences in photolysis rates lead to changes in gas concentrations, with the largest impact simulated for OH and NO concentrations. At the ground, monthly mean concentrations of both species are reduced over Europe by around 10 to 14% and their tropospheric burden by around 10

  16. Reactive hydro- end chlorocarbons in the troposphere and lower stratosphere : sources, distributions, and chemical impact

    NARCIS (Netherlands)

    Scheeren, H.A.

    2003-01-01

    The work presented in this thesis focuses on measurements of chemical reactive C2 C7 non-methane hydrocarbons (NMHC) and C1 C2 chlorocarbons with atmospheric lifetimes of a few hours up to about a year. The group of reactive chlorocarbons includes the most abundant atmospheric species with large

  17. Impact of environmental chemicals on the thyroid hormone function in pituitary rat GH3 cells

    DEFF Research Database (Denmark)

    Ghisari, Mandana; Bonefeld-Jørgensen, Eva

    2005-01-01

    -nonylphenol, 4-octylphenol), pesticides (prochloraz, iprodion, chlorpyrifos), PCB metabolites (OH-PCB 106, OH-PCB 121, OH-PCB 69) and brominated flame-retardants (tetrabromobisphenol A). The ED potential of a chemical was determined by its effect on the cell proliferation of TH-dependent rat pituitary GH3 cell...

  18. 76 FR 41365 - Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 2A Chemical...

    Science.gov (United States)

    2011-07-13

    ... requirements consistent with the international agreement adopted by the Organization for the Prohibition of... threshold. Legislative amendment of the Chemical Weapons Convention Implementation Act (CWCIA) is required in order to implement this proposed amendment to the CWCR. In addition, at U.S. national...

  19. 76 FR 41371 - Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 3 Chemical...

    Science.gov (United States)

    2011-07-13

    ... conform with the low concentration exemption adopted by the Organization for the Prohibition of Chemical... Implementation Act (CWCIA). Accordingly, publication and implementation of regulatory changes affecting this low..., consistent with U.S. national discretion, BIS is considering amending the CWCR reporting requirements...

  20. Study of Environmental Impacts Before and After Using the Organic-Chemical Fertilizer in Rice Paddy Fields

    OpenAIRE

    Wipawee KHAMWICHIT; Wipada SANONGRAJ; Sompop SANONGRAJ

    2006-01-01

    The environmental impact of an organic-chemical fertilizer developed by the Institute of National Science and Technology has been studied at Bansrangsabaeng Posai Ubonratchathani. The study revealed that the values of pH, EC, OC, total N, available P, and exchangeable K in soils from two varieties of rice tested Kor-Khor 10 and         Kor-Khor 15 paddy fields are almost the same. The concentrations of VOC, NH3, and CH4 in the air from the rice paddy fields mentioned above are lower than 0....

  1. Acute and Long-Term Impact of Chemical Weapons: Lessons from the Iran-Iraq War.

    Science.gov (United States)

    Haines, D D; Fox, S C

    2014-07-01

    Chemical weapons have given the human experience of warfare a uniquely terrifying quality that has inspired a general repugnance and led to periodic attempts to ban their use. Nevertheless, since ancient times, toxic agents have been consistently employed to kill and terrorize target populations. The evolution of these weapons is examined here in ways that may allow military, law enforcement, and scientific professionals to gain a perspective on conditions that, in the past, have motivated their use - both criminally and as a matter of national policy during military campaigns. Special emphasis is placed on the genocidal use of chemical weapons by the regime of Saddam Hussein, both against Iranians and on Kurdish citizens of his own country, during the Iran-Iraq War of 1980-88. The historical development of chemical weapons use is summarized to show how progressively better insight into biochemistry and physiology was adapted to this form of warfare. Major attributes of the most frequently used chemical agents and a description of how they affected military campaigns are explained. Portions of this review describing chemical-casualty care devote particular focus to Iranian management of neurotoxic (nerve) agent casualties due to the unique nature of this experience. Both nerve and blistering "mustard" agents were used extensively against Iranian forces. However, Iran is the only nation in history to have sustained large-scale attacks with neurotoxic weapons. For this reason, an understanding of the successes and failures of countermeasures to nerve-agent use developed by the Iranian military are particularly valuable for future civil defense and military planning. A detailed consideration of these strategies is therefore considered. Finally, the outcomes of clinical research into severe chronic disease triggered by mustard-agent exposure are examined in the context of the potential of these outcomes to determine the etiology of illness among US and Allied veterans

  2. Chemical fingerprint and impact of shipping emissions over a western Mediterranean metropolis: Primary and aged contributions

    International Nuclear Information System (INIS)

    An intensive monitoring campaign was carried out in the harbor of Barcelona (Spain) to quantify the contribution of primary shipping emissions (PSE) on PM10. Chemical composition of inorganic species, as well as OC and EC, was completed, and a source apportionment analysis by Positive Matrix Factorization was conducted. Among the 6 sources extracted, two were linked to harbor emissions: dusty materials released in different areas along the harbor and fuel–oil combustion. On average, harbor emissions accounted for 31% of the PM10 mass. Since the chemical signature of PSE was not determined neither their contribution was obtained, additional approaches were followed and mainly consisted in: 1) the evaluation of V/Ni and V/Cu ratios to identify those days affected by PSE; 2) the identification of the chemical components increasing under the influence of PSE; 3) the calculation of the daily and average PSE from their experimentally-determined chemical signature and the experimental concentrations of vanadium. As a result, the contribution of PSE was estimated in 0.84 μg m−3 (2.7% of PM10) and the residual fuel–oil combustion factor (3.6 μg m−3, 12% of PM10) was interpreted as aged shipping emissions. The present study splits the contribution of shipping emissions into primary and aged, and highlights the importance of atmospheric mixing and aging processes in western Mediterranean atmospheres. In the case of shipping emissions, the aged products were found to be dominant with respect to the primary ones even in the vicinity of the source. Highlights: • Primary and aged shipping emissions were quantified. • An experimental chemical profile for primary shipping emissions is provided. • Aged shipping emissions prevailed even in the proximity of the emission source

  3. Chemical fingerprint and impact of shipping emissions over a western Mediterranean metropolis: Primary and aged contributions

    Energy Technology Data Exchange (ETDEWEB)

    Pey, Jorge, E-mail: jorge.pey@univ-amu.fr [Institute of Environmental Assessment and Water Research, IDÆA-CSIC, 08034 Barcelona (Spain); Aix-Marseille Université, CNRS, LCE FRE 3416, 13331 Marseille (France); Department of Epidemiology, Lazio Region, 00198 Roma (Italy); Pérez, Noemí [Institute of Environmental Assessment and Water Research, IDÆA-CSIC, 08034 Barcelona (Spain); Department of Epidemiology, Lazio Region, 00198 Roma (Italy); Cortés, Joaquim [Autoriat Portuaria de Barcelona, 08002 Barcelona (Spain); Alastuey, Andrés; Querol, Xavier [Institute of Environmental Assessment and Water Research, IDÆA-CSIC, 08034 Barcelona (Spain)

    2013-10-01

    An intensive monitoring campaign was carried out in the harbor of Barcelona (Spain) to quantify the contribution of primary shipping emissions (PSE) on PM{sub 10}. Chemical composition of inorganic species, as well as OC and EC, was completed, and a source apportionment analysis by Positive Matrix Factorization was conducted. Among the 6 sources extracted, two were linked to harbor emissions: dusty materials released in different areas along the harbor and fuel–oil combustion. On average, harbor emissions accounted for 31% of the PM{sub 10} mass. Since the chemical signature of PSE was not determined neither their contribution was obtained, additional approaches were followed and mainly consisted in: 1) the evaluation of V/Ni and V/Cu ratios to identify those days affected by PSE; 2) the identification of the chemical components increasing under the influence of PSE; 3) the calculation of the daily and average PSE from their experimentally-determined chemical signature and the experimental concentrations of vanadium. As a result, the contribution of PSE was estimated in 0.84 μg m{sup −3} (2.7% of PM{sub 10}) and the residual fuel–oil combustion factor (3.6 μg m{sup −3}, 12% of PM{sub 10}) was interpreted as aged shipping emissions. The present study splits the contribution of shipping emissions into primary and aged, and highlights the importance of atmospheric mixing and aging processes in western Mediterranean atmospheres. In the case of shipping emissions, the aged products were found to be dominant with respect to the primary ones even in the vicinity of the source. Highlights: • Primary and aged shipping emissions were quantified. • An experimental chemical profile for primary shipping emissions is provided. • Aged shipping emissions prevailed even in the proximity of the emission source.

  4. Reverse Pulse Voltammetry at Spherical and Disc Microelectrodes: Characterization of Homogeneous Chemical Equilibria and Their Impact on the Species Diffusivities

    International Nuclear Information System (INIS)

    The value of the electrochemical technique Reverse Pulse Voltammetry (RPV) for the characterization of chemical equilibria in solution is theoretically investigated. For this, the RPV response of the square scheme is studied at spherical and disc electrodes of any size assuming that the chemical reactions are at equilibrium. When the effective diffusion coefficients of the oxidized and reduced species are the same, analytical solutions are reported for both electrode geometries. Otherwise, a rigorous analytical solution is derived for spherical electrodes whereas the case of microdiscs is addressed by numerical simulations. The theory for the square scheme enables the study of the RPV response in very different situations, including the cases where the electrochemical and/or chemical transformations alter significantly the species diffusivity such as in electron transfer processes in room temperature ionic liquids or in the association of the electroactive species with (bio) macromolecules and nanoparticles. It is found that, when medium-size (disc or spherical) microelectrodes are employed, the RPV method enables the simultaneous determination of the effective diffusion coefficients of the oxidized and reduced species as well as the apparent formal potential. These magnitudes make it possible a sound physicochemical characterization of the system

  5. From theory to practice: improving the impact of health services research

    Directory of Open Access Journals (Sweden)

    Levine Robert

    2005-01-01

    Full Text Available Abstract Background While significant strides have been made in health research, the incorporation of research evidence into healthcare decision-making has been marginal. The purpose of this paper is to provide an overview of how the utility of health services research can be improved through the use of theory. Integrating theory into health services research can improve research methodology and encourage stronger collaboration with decision-makers. Discussion Recognizing the importance of theory calls for new expectations in the practice of health services research. These include: the formation of interdisciplinary research teams; broadening the training for those who will practice health services research; and supportive organizational conditions that promote collaboration between researchers and decision makers. Further, funding bodies can provide a significant role in guiding and supporting the use of theory in the practice of health services research. Summary Institutions and researchers should incorporate the use of theory if health services research is to fulfill its potential for improving the delivery of health care.

  6. Computational Study of Chemical Reactivity Using Information-Theoretic Quantities from Density Functional Reactivity Theory for Electrophilic Aromatic Substitution Reactions.

    Science.gov (United States)

    Wu, Wenjie; Wu, Zemin; Rong, Chunying; Lu, Tian; Huang, Ying; Liu, Shubin

    2015-07-23

    The electrophilic aromatic substitution for nitration, halogenation, sulfonation, and acylation is a vastly important category of chemical transformation. Its reactivity and regioselectivity is predominantly determined by nucleophilicity of carbon atoms on the aromatic ring, which in return is immensely influenced by the group that is attached to the aromatic ring a priori. In this work, taking advantage of recent developments in quantifying nucleophilicity (electrophilicity) with descriptors from the information-theoretic approach in density functional reactivity theory, we examine the reactivity properties of this reaction system from three perspectives. These include scaling patterns of information-theoretic quantities such as Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy and information gain at both molecular and atomic levels, quantitative predictions of the barrier height with both Hirshfeld charge and information gain, and energetic decomposition analyses of the barrier height for the reactions. To that end, we focused in this work on the identity reaction of the monosubstituted-benzene molecule reacting with hydrogen fluoride using boron trifluoride as the catalyst in the gas phase. We also considered 19 substituting groups, 9 of which are ortho/para directing and the other 9 meta directing, besides the case of R = -H. Similar scaling patterns for these information-theoretic quantities found for stable species elsewhere were disclosed for these reactions systems. We also unveiled novel scaling patterns for information gain at the atomic level. The barrier height of the reactions can reliably be predicted by using both the Hirshfeld charge and information gain at the regioselective carbon atom. The energy decomposition analysis ensued yields an unambiguous picture about the origin of the barrier height, where we showed that it is the electrostatic interaction that plays the dominant role, while the roles played by exchange-correlation and

  7. PARTICULAR ASPECTS OF APPLICABILITY OF PROVISIONS OF THE PHYSICAL AND CHEMICAL THEORY OF EFFECTIVE STRESSES TO SANDY SOILS

    Directory of Open Access Journals (Sweden)

    Potapov Aleksandr Dmitrievich

    2012-10-01

    V.I. Osipov. The analysis of several genetic types of quaternary sands, performed by the authors, makes it possible to use the number of contacts to identify the morphology of sand grains within the framework of the analysis of soils. The authors demonstrate that the employment of the formulas developed by academician V.I. Osipov in the calculation of the number of contacts between particles in natural sandy soils is virtually impossible due to the fact that no natural sand particles can boast an ideal spherical shape. The number of contacts between the sand particles may increase due to the defects of their shape and the nature of the particle surface. In this study, the shape and nature of the surface of sand grains represent those of the sands of various origins. The authors have employed a composite index of morphology that takes account of the shape and nature of the surface throughout the amount of sand under research. Similar calculations that take account of the morphology of grains were performed for selected fractions of sands to eliminate the influence of grain size on the packing of sands. The analysis of provisions of the physical and chemical theory of effective stresses of soils and the study of multiple types of natural sands demonstrate that further research of formation and phases of coagulation contacts between particles of soil requires a detailed study of structural features of sands. These structural features include the grain size, homogeneity, the shape and nature of the surface of sand grains. Both individual particles of sand and sandy soil are to be subjected to morphological assessments. The parameters to be assessed will include density and composition of sandy soils, as the soil porosity affects the formation of true contacts between particles of sand and determines their number. Mineral composition is an important factor affecting the shape and nature of the surface of sand grains. The research performed by the authors contemplates

  8. Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil.

    Science.gov (United States)

    Sutton, Nora B; Grotenhuis, Tim; Rijnaarts, Huub H M

    2014-02-01

    Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton's reagent and modified Fenton's reagent coupled with a subsequent bioremediation phase of 187d, both with and without nutrient amendment. Chemical oxidation mobilized SOM into the liquid phase, producing dissolved organic carbon (DOC) concentrations 8-16 times higher than the untreated field sample. Higher aqueous concentrations of nitrogen and phosphorous species were also observed following oxidation; NH4(+) increased 14-172 times. During the bioremediation phase, dissolved carbon and nutrient species were utilized for microbial growth-yielding DOC concentrations similar to field sample levels within 56d of incubation. In the absence of nutrient amendment, the highest microbial respiration rates were correlated with higher availability of nitrogen and phosphorus species mobilized by oxidation. Significant diesel degradation was only observed following nutrient amendment, implying that nutrients mobilized by chemical oxidation can increase microbial activity but are insufficient for bioremediation. While all bioremediation occurred in the first 28d of incubation in the biotic control microcosm with nutrient amendment, biodegradation continued throughout 187d of incubation following chemical oxidation, suggesting that chemical treatment also affects the desorption of organic contaminants from SOM. Overall, results indicate that biodegradation of DOC, as an alternative substrate to diesel, and biological utilization of mobilized nutrients have implications for the success of coupled ISCO and ISB treatments.

  9. The Hercules Cluster Environment Impact on the Chemical History of Star-Forming Galaxies

    Science.gov (United States)

    Petropoulou, V.; VíLchez, J. M.; Iglesias-Páramo, J.; Papaderos, P.

    In this work we study the effects of the Hercules cluster environment on the chemical history of star-forming (SF) galaxies. For this purpose we have derived the gas metallicities, the mean stellar metallicities and ages, the masses and the luminosities of our sample of galaxies. We have found that our Hercules SF galaxies are either chemically evolved spirals with nearly flat oxygen gradients, or less metal-rich dwarf galaxies which appear to be the "newcomers" in the cluster. Most Hercules SF galaxies follow well defined mass-metallicity and luminosity-metallicity sequences; nevertheless significant outliers to these relations have been identified, illustrating how environmental effects can provide a physical source of dispersion in these fundamental relations.

  10. Chemical and Physical Parameters Impact on Sulphorhodamine G Extra Spectral Determinations

    Science.gov (United States)

    Kola, Liljana; Amataj, Sokrat

    2010-01-01

    Some chemical compound with fluorescence properties can be used as artificial tracers for water system studies. The problem in this case is dealt with in relation to applying Sulphorhodamine G Extra to trace and study underground communications between Prespa and Ohrid Lakes. The fluorescence intensity of Sulphorhodamine G Extra (SRG) in water samples depends on their chemical and physical properties, such as pH, presence of oxidants, temperature, etc. This paper presents the experience of the Center of Applied Nuclear Physics, Tirana, in this field. The method we have elaborated to this purpose made it possible to optimize procedures we use to analyze water samples for the presence of Sulphorhodamine G Extra and measure its content, even in trace levels, by the means of a Perkin Elmer LS 55 Luminiscence Spectrometer.

  11. Impact of chabazite SSZ-13 textural properties and chemical composition on CO2 adsorption applications

    Energy Technology Data Exchange (ETDEWEB)

    Prodinger, Sebastian; Vemuri, Venkata Rama Ses; Varga, Tamas; McGrail, B. Peter; Motkuri, Radha K.; Derewinski, Miroslaw A.

    2016-04-01

    Chabazite SSZ-13 samples with varying silica content (Si/Al from 6 to 35) were synthesized in both stirring and static conditions to obtain material with changing particle size and morphology and thoroughly analysed with various characterization techniques. The role of particle size and chemical compositions of SSZ-13 chabazite on CO2 and N2 adsorption measurements was investigated. The Si/Al ratio played a major role for CO2 adsorption with Al-rich SSZ-13 showing a higher CO2 uptake than Al-poor material. This was attributed to the high density of active charged species in the chabazite cage. Particle size also played an important role in the sorption capacities with smaller particles, obtained in stirring conditions, showing enhanced CO2 uptakes compared to larger particles of same chemical composition. This was associated with an increased density of surface active sites and shorter diffusion pathways.

  12. Impact of synthetic biology and metabolic engineering on industrial production of fine chemicals.

    Science.gov (United States)

    Jullesson, David; David, Florian; Pfleger, Brian; Nielsen, Jens

    2015-11-15

    Industrial bio-processes for fine chemical production are increasingly relying on cell factories developed through metabolic engineering and synthetic biology. The use of high throughput techniques and automation for the design of cell factories, and especially platform strains, has played an important role in the transition from laboratory research to industrial production. Model organisms such as Saccharomyces cerevisiae and Escherichia coli remain widely used host strains for industrial production due to their robust and desirable traits. This review describes some of the bio-based fine chemicals that have reached the market, key metabolic engineering tools that have allowed this to happen and some of the companies that are currently utilizing these technologies for developing industrial production processes.

  13. Impact of synthetic biology and metabolic engineering on industrial production of fine chemicals

    DEFF Research Database (Denmark)

    Jullesson, David; David, Florian; Pfleger, Brian;

    2015-01-01

    Industrial bio-processes for fine chemical production are increasingly relying on cell factories developed through metabolic engineering and synthetic biology. The use of high throughput techniques and automation for the design of cell factories, and especially platform strains, has played...... chemicals that have reached the market, key metabolic engineering tools that have allowed this to happen and some of the companies that are currently utilizing these technologies for developing industrial production processes....... an important role in the transition from laboratory research to industrial production. Model organisms such as Saccharomyces cerevisiae and Escherichia coli remain widely used host strains for industrial production due to their robust and desirable traits. This review describes some of the bio-based fine...

  14. The Impact of Multiple Master Patient Index Records on the Business Performance of Health Care Organizations: A Qualitative Grounded Theory Study

    Science.gov (United States)

    Banton, Cynthia L.

    2014-01-01

    The purpose of this qualitative grounded theory study was to explore and examine the factors that led to the creation of multiple record entries, and present a theory on the impact the problem has on the business performance of health care organizations. A sample of 59 health care professionals across the United States participated in an online…

  15. The impact of local geochemical variability on quantifying hillslope soil production and chemical weathering

    Science.gov (United States)

    Heimsath, Arjun M.; Burke, Benjamin C.

    2013-10-01

    Soil-mantled upland landscapes are widespread across the habitable world, support extensive life, and are the interface between the atmosphere, hydrosphere, and lithosphere but typically are not cultivated. Soil found across such landscapes fits the conceptual framework of a physically mobile layer derived from the underlying parent material along with some locally derived organic content. The extent and persistence of these upland soils depend on the long-term balance between soil production and erosion. Here we briefly review methods used to quantify the physical and chemical processes of soil production and erosion and revisit three granitic study areas in southeastern Australia and northern California that enabled early quantification of the soil production function and topographic controls on chemical weathering. We then present new major and trace element data from 2-m by 2-m pits dug at each field site to quantify local variability of Zr concentrations and the chemical index of alteration (CIA), weathering indices used to determine chemical weathering rates and extents in soils and saprolites. Using both new and previously published data, we compare differences between local variability and regional, as well as intersite variability of these important indices. For each of the 2-m pits, we collected 25 samples and found that the simple mean and the 2σ standard deviation best describe the local variation in the data. We also find that the variability in the 2-m pit data lies within variability observed in the same data from samples collected in individual soil pits across each of the field sites and that the differences between sites are consistent with previously published results. These observations highlight the importance of quantifying local scale variability in studies that use similar, multifaceted measurements to quantify hillslope soil production and erosion processes.

  16. Impact of chemical shock loads on a membrane bioreactor for urban wastewater reuse

    OpenAIRE

    Knops, Geraldine Jane Augustine

    2010-01-01

    The performance of an MBR under chemical shock loading conditions was investigated, to ascertain the robustness of the treatment system for urban water reuse. 32 household products and industrial substances, likely to be found in urban wastewater were assessed for toxicity, using Microtox and respirometry to obtain EC50 values. Six of these toxins were dosed into bench scale porous pots to observe any detrimental effects on the treatment system, in terms of effluent quality ...

  17. Estrogenic and anti-androgenic endocrine disrupting chemicals and their impact on the male reproductive system

    OpenAIRE

    De Falco, Maria; Forte, Maurizio; Laforgia, Vincenza

    2015-01-01

    Endocrine disrupting chemicals (EDCs) are identified for their ability to perturb the homeostasis of endocrine system and hormonal balance. The male reproductive system is under close control of hormones and each change in their concentration and time of exposition and action can induce a deregulation of its physiology. In this review we summarize the most recent studies on two main categories of EDCs with different action: the estrogenic bisphenol A and alkylphenols and the anti-androgenic p...

  18. A path forward in the debate over health impacts of endocrine disrupting chemicals

    OpenAIRE

    Zoeller, R. Thomas; Bergman, Åke; Becher, Georg; Bjerregaard, Poul; Bornman, Riana; Brandt, Ingvar; Iguchi, Taisen; Jobling, Susan; Kidd, Karen A.; Kortenkamp, Andreas; Skakkebæk, Niels E.; Toppari, Jorma; Laura N. Vandenberg

    2014-01-01

    Several recent publications reflect debate on the issue of "endocrine disrupting chemicals" (EDCs), indicating that two seemingly mutually exclusive perspectives are being articulated separately and independently. Considering this, a group of scientists with expertise in basic science, medicine and risk assessment reviewed the various aspects of the debate to identify the most significant areas of dispute and to propose a path forward. We identified four areas of debate. The first is about th...

  19. Impact of Biofield Treatment on Chemical and Thermal Properties of Cellulose and Cellulose Acetate

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Cellulose being an excellent biopolymer has cemented its place firmly in many industries as a coating material, textile, composites, and biomaterial applications. In the present study, we have investigated the effect of biofield treatment on physicochemical properties of cellulose and cellulose acetate. The cellulose and cellulose acetate were exposed to biofield and further the chemical and thermal properties were investigated. X-ray diffraction study asserted that the biofield treatment did...

  20. Modelling the chemically aged and mixed aerosols over the eastern central Atlantic Ocean – potential impacts

    Directory of Open Access Journals (Sweden)

    M. Astitha

    2010-07-01

    Full Text Available Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size distribution, using chemistry-transport models, satellite data and in situ measurements. We focus on August 2005, a period with intense hurricane and tropical storm activity over the Atlantic Ocean. A mixture of anthropogenic (sulphates, nitrates, natural (desert dust, sea salt and chemically aged (sulphate and nitrate on dust aerosols is found entering the hurricane genesis region, most likely interacting with clouds in the area. Results from our modelling study suggest rather small amounts of accumulation mode desert dust, sea salt and chemically aged dust aerosols in this Atlantic Ocean region. Aerosols of smaller size (Aitken mode are more abundant in the area and in some occasions sulphates of anthropogenic origin and desert dust are of the same magnitude in terms of number concentrations. Typical aerosol number concentrations are derived for the vertical layers near shallow cloud formation regimes, indicating that the aerosol number concentration can reach several thousand particles per cubic centimetre. The vertical distribution of the aerosols shows that the desert dust particles are often transported near the top of the marine cloud layer as they enter into the region where deep convection is initiated. The anthropogenic sulphate aerosol can be transported within a thick layer and enter the cloud deck through multiple ways (from the top, the base of the cloud, and by entrainment. The sodium (sea salt related aerosol is mostly found below the cloud base. The results of this work may provide insights relevant for studies that consider aerosol influences on cloud processes and storm development in the Central Atlantic region.

  1. Chemically aged and mixed aerosols over the Central Atlantic Ocean – potential impacts

    Directory of Open Access Journals (Sweden)

    H. A. C. Denier van der Gon

    2010-02-01

    Full Text Available Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size distribution, using chemistry-transport models, satellite data and in situ measurements. We focus on August 2005, a period with intense hurricane and tropical storm activity over the Atlantic Ocean. A mixture of anthropogenic (sulphates, nitrates, natural (desert dust, sea salt and chemically aged (sulphate and nitrate on dust aerosols is found entering the hurricane genesis region, most likely interacting with clouds in the area. Results from our modelling study suggest rather small amounts of accumulation mode desert dust, sea salt and chemically aged dust aerosols in this Atlantic Ocean region. Aerosols of smaller size (Aitken mode are more abundant in the area and in some occasions sulphates of anthropogenic origin and desert dust are of the same magnitude in terms of number concentrations. Typical aerosol number concentrations are derived for the vertical layers near shallow cloud formation regimes, designating that the aerosol number concentration can reach several thousand particles per cubic centimetre. The vertical distribution of the aerosols indicates that the desert dust particles are often transported near the top of the marine cloud layer as they enter into the region where deep convection is initiated. The anthropogenic sulphate aerosol can be transported within a thick layer and enter the cloud deck through multiple ways (from the top, the base of the cloud and entrainment. The sodium (sea salt related aerosol is mostly found below the cloud base. The results of this work may provide insights relevant for studies that consider aerosol influences on cloud processes and storm development in the Central Atlantic region.

  2. Evaluation of 3D printing and its potential impact on biotechnology and the chemical sciences.

    Science.gov (United States)

    Gross, Bethany C; Erkal, Jayda L; Lockwood, Sarah Y; Chen, Chengpeng; Spence, Dana M

    2014-04-01

    Nearing 30 years since its introduction, 3D printing technology is set to revolutionize research and teaching laboratories. This feature encompasses the history of 3D printing, reviews various printing methods, and presents current applications. The authors offer an appraisal of the future direction and impact this technology will have on laboratory settings as 3D printers become more accessible.

  3. Daily and hourly chemical impact of springtime transboundary aerosols on Japanese air quality

    NARCIS (Netherlands)

    Moreno, T.; Kojima, T.; Amato, F.; Lucarelli, F.; Rosa, J. de la; Calzolai, G.; Nava, S.; Chiari, M.; Alastuey, A.; Querol, X.; Gibbons, W.

    2013-01-01

    The regular eastward drift of transboundary aerosol intrusions from the Asian mainland into the NW Pacific region has a pervasive impact on air quality in Japan, especially during springtime. Analysis of 24-h filter samples with Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and M

  4. Adolescent Health Promotion Model and The Impact of Oral Health Behavior of Nursing Intervention Applied to The Information Proccessing Theory

    OpenAIRE

    Üstüner Top, Fadime; Ocakçı, Ayşe Ferda

    2012-01-01

    This research is planned to assess the impact of oral and dental health behavior of nursing intervention applied to Health Promotion Model and the Information Processing Theory of adolescents with low oral and dental health behavior. The method of research is experimental design with pre-test and post test control groups. According to the results of oral health care form, individuals that form %25 of the slice on attitude scale are placed in the experimental (n=40) and control (n=40) groups w...

  5. Connected and Ubiquitous: A Discussion of Two Theories That Impact Future Learning Applications

    Science.gov (United States)

    Bair, Richard A.; Stafford, Timothy

    2016-01-01

    Mobile media break down traditional barriers that have defined learning in schools because they enable constant, personalized access to media. This information-rich environment could dramatically expand learning opportunities. This article identifies and discusses two instructional design theories for mobile learning including the major…

  6. Impact of the chemicals, essential for the purification process of strict Fe-hydrogenase, on the corrosion of mild steel.

    Science.gov (United States)

    Rouvre, Ingrid; Gauquelin, Charles; Meynial-Salles, Isabelle; Basseguy, Régine

    2016-06-01

    The influence of additional chemical molecules, necessary for the purification process of [Fe]-hydrogenase from Clostridium acetobutylicum, was studied on the anaerobic corrosion of mild steel. At the end of the purification process, the pure [Fe-Fe]-hydrogenase was recovered in a Tris-HCl medium containing three other chemicals at low concentration: DTT, dithionite and desthiobiotin. Firstly, mild steel coupons were exposed in parallel to a 0.1 M pH7 Tris-HCl medium with or without pure hydrogenase. The results showed that hydrogenase and the additional molecules were in competition, and the electrochemical response could not be attributed solely to hydrogenase. Then, solutions with additional chemicals of different compositions were studied electrochemically. DTT polluted the electrochemical signal by increasing the Eoc by 35 mV 24 h after the injection of 300 μL of control solutions with DTT, whereas it drastically decreased the corrosion rate by increasing the charge transfer resistance (Rct 10 times the initial value). Thus, DTT was shown to have a strong antagonistic effect on corrosion and was removed from the purification process. An optimal composition of the medium was selected (0.5 mM dithionite, 7.5 mM desthiobiotin) that simultaneously allowed a high activity of hydrogenase and a lower impact on the electrochemical response for corrosion tests.

  7. Impact of Sulfuric Acid Treatment of Halloysite on Physico-Chemic Property Modification

    Directory of Open Access Journals (Sweden)

    Tayser Sumer Gaaz

    2016-07-01

    Full Text Available Halloysite (HNT is treated with sulfuric acid and the physico-chemical properties of its morphology, surface activity, physical and chemical properties have been investigated when HNT is exposed to sulfuric acid with treatment periods of 1 h (H1, 3 h (H3, 8 h (H8, and 21 h (H21. The significance of this and similar work lies in the importance of using HNT as a functional material in nanocomposites. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR. The spectrum demonstrates that the hydroxyl groups were active for grafting modification using sulfuric acid, promoting a promising potential use for halloysite in ceramic applications as filler for novel clay-polymer nanocomposites. From the X-ray diffraction (XRD spectrum, it can be seen that the sulfuric acid breaks down the HNT crystal structure and alters it into amorphous silica. In addition, the FESEM images reveal that the sulfuric acid treatment dissolves the AlO6 octahedral layers and induces the disintegration of SiO4 tetrahedral layers, resulting in porous nanorods. The Bruncher-Emmett-Teller (BET surface area and total pore volume of HNTs showed an increase. The reaction of the acid with both the outer and inner surfaces of the nanotubes causes the AlO6 octahedral layers to dissolve, which leads to the breakdown and collapse of the tetrahedral layers of SiO4. The multi-fold results presented in this paper serve as a guide for further HNT functional treatment for producing new and advanced nanocomposites.

  8. Application of Chemically Accelerated Biotreatment to Reduce Risk in Oil-Impacted Soils

    Energy Technology Data Exchange (ETDEWEB)

    Paterek, J.R.; Bogan, W.W.; Lahner, L.M.; Trbovic, V.

    2003-03-06

    Conducted research in the following major focus areas: (1) Development of mild extraction approaches to estimate bioavailable fraction of crude oil residues in contaminated soils; (2) Application of these methods to understand decreases in toxicity and increases in sequestration of hydrocarbons over time, as well as the influence of soil properties on these processes; (3) Measurements of the abilities of various bacteria (PAH-degraders and others more representative of typical soil bacteria) to withstand oxidative treatments (i.e. Fenton's reaction) which would occur in CBT; and (4) Experiments into the biochemical/genetic inducibility of PAH degradation by compounds formed by the chemical oxidation of PAH.

  9. Estrogenic and anti-androgenic endocrine disrupting chemicals and their impact on the male reproductive system.

    Directory of Open Access Journals (Sweden)

    Maria eDe Falco

    2015-02-01

    Full Text Available Endocrine disrupting chemicals (EDCs are identified for their ability to perturb the homeostasis of endocrine system and hormonal balance. The male reproductive system is under close control of hormones and each change in their concentration and time of exposition and action can induce a deregulation of its physiology. In this review we summarize the most recent studies on two main categories of EDCs with different action: the estrogenic bisphenol A and alkylphenols and the anti-androgenic phthalates. This review describes the main effects of these substances on male reproductive system.

  10. The Impact of Information and Communication Technology on Interorganizational Coordination: Guidelines from Theory

    Directory of Open Access Journals (Sweden)

    Mariëlle den Hengst

    2001-01-01

    Full Text Available It is widely believed that information and communication technology (ICT enables organizations to decrease costs and increase capabilities and thus enables to shape interorganizational coordination. This paper describes guidelines with which the impact of ICT on interorganizational coordination structures can be predicted. The framework used consists of three perspectives: interorganizational coordination structures, ICT, and aspects of goods and services for the processing of which coordination is required. Interorganizational coordination structures are defined and the impact of ICT on coordination structures is indicated. So far, ICT is considered to be a driving force. There are, however, other aspects that have an influencing impact on interorganizational coordination. Those aspects are described and by combining those with the possibilities of ICT, the guidelines are presented.

  11. A path forward in the debate over health impacts of endocrine disrupting chemicals.

    Science.gov (United States)

    Zoeller, R Thomas; Bergman, Åke; Becher, Georg; Bjerregaard, Poul; Bornman, Riana; Brandt, Ingvar; Iguchi, Taisen; Jobling, Susan; Kidd, Karen A; Kortenkamp, Andreas; Skakkebaek, Niels E; Toppari, Jorma; Vandenberg, Laura N

    2014-01-01

    Several recent publications reflect debate on the issue of "endocrine disrupting chemicals" (EDCs), indicating that two seemingly mutually exclusive perspectives are being articulated separately and independently. Considering this, a group of scientists with expertise in basic science, medicine and risk assessment reviewed the various aspects of the debate to identify the most significant areas of dispute and to propose a path forward. We identified four areas of debate. The first is about the definitions for terms such as "endocrine disrupting chemical", "adverse effects", and "endocrine system". The second is focused on elements of hormone action including "potency", "endpoints", "timing", "dose" and "thresholds". The third addresses the information needed to establish sufficient evidence of harm. Finally, the fourth focuses on the need to develop and the characteristics of transparent, systematic methods to review the EDC literature. Herein we identify areas of general consensus and propose resolutions for these four areas that would allow the field to move beyond the current and, in our opinion, ineffective debate. PMID:25533907

  12. Sr isotope evolution during chemical weathering of granites -- impact of relative weathering rates of minerals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Sr isotopic systematics in the weathering profiles of biotite granite and granite porphyry in southern Jiangxi Province were investigated. The results showed that during the chemical weathering of granites, remarked fractionation occurred between Rb and Sr. During the early stages of chemical weathering of granites, the released Sr/Si and Sr/Ca ratios are larger than those of the parent rocks, and the leaching rate of Sr is higher than those of Si, Ca, K, Rb, etc. Dynamic variations in relative weathering rates of the main Sr-contributing minerals led to fluctuation with time in 87Sr/86Sr ratios of inherent and released Sr in the weathering crust of granite. Successive weathering of biotite, plagioclase and K-feldspar made 87Sr/86Sr ratios in the weathering residues show such a fluctuation trend as to decrease first, increase, and then decrease again till they maintain stable. This work further indicates that when Sr isotopes are used to trace biogeochemical processes on both the catchment and global scales, one must seriously take account of the prefer-ential release of Sr from dissolving solid phase and the fluctuation of 87Sr/86Sr ratios caused by the variations of relative weathering rates of Sr-contributing minerals.

  13. Analysis of Innovation and Its Environmental Impacts on the Chemical Industry

    Directory of Open Access Journals (Sweden)

    Dusan Schreiber

    2016-01-01

    Full Text Available Globalization of the economy and the need to achieve competitiveness drive organizations to invest in technology and in innovation, in order to find solutions that will provide advantages in an ever-more competitive market. The conflict between dwindling natural resources and the demand for economic growth has created a growing need to find means for making environmental conservation compatible with economic growth. The objective of this study is to contribute to the debate by analyzing the innovations implemented by chemical companies in the Sinos Valley region, Rio Grande do Sul, Brazil, and by identifying the motivations that drive them to develop environmental technologies. The study is exploratory and descriptive, with a quantitative data collection component in the form of a survey sent to all chemical companies in the Sinos Valley region, listed in a local business association database. The study results indicate that development of innovations is predominantly of an incremental nature and that novelty is generally restricted to the new-for-firm level. The environmental technologies implemented are generally designed to prevent or remedy environmental damage and are primarily motivated by the need to comply with environmental standards and legislation.

  14. Impact of Blended Learning Environments Based on Algo-Heuristic Theory on Some Variables

    Directory of Open Access Journals (Sweden)

    Mustafa AYGÜN

    2012-12-01

    Full Text Available In this study, the effects of Algo–Heuristic Theory based blended learning environments on students’ computer skills in their preparation of presentations, levels of attitudes towards computers, and levels of motivation regarding the information technology course were investigated. The research sample was composed of 71 students. A semi–empirical design with a pre-test–post-test, and control group was used. Research data was collected using an Academic Achievement Test, the Computer Attitude Scale for Primary School Students and the Motivation Scale for the Information Technology Course. A one way ANOVA was conducted on all the data collected and the results revealed that the achievements and motivation levels of the students who studied in an Algo–Heuristic Theory based blended learning environment in the information technology course increased significantly.

  15. Edutainment's Impact on Health Promotion: Viewing The Biggest Loser Through the Social Cognitive Theory.

    Science.gov (United States)

    Mocarski, Richard; Bissell, Kimberly

    2016-01-01

    Through a critical rhetorical analysis using Bandura's social cognitive theory as a lens to view The Biggest Loser (TBL), this article illustrates the contradictions between the show's health promotional aims and its entertainment aims, which show the problems the show creates for health promotion practitioners working on obesity. The social cognitive theory constructs of observational learning, psychological determinants, and environmental determinants emerged from this reading of TBL as central to how the show masquerades as a health promotion tool. This reading reveals that TBL promotes a neoliberal construction of health and obesity that challenges the worldview that many health promotion campaigns take and, therefore, complicates our own efforts to combat obesity. With this revealed, it is suggested that TBL be incorporated into health promotion campaigns only as a foil.

  16. Impact of the Delta (1232) resonance on neutral pion photoproduction in chiral perturbation theory

    CERN Document Server

    Cawthorne, Lloyd W

    2015-01-01

    We present an ongoing project to assess the importance of D-waves and the $\\Delta (1232)$ resonance for descriptions of neutral pion photoproduction in Heavy Baryon Chiral Perturbation Theory. This research has been motivated by data published by the A2 and CB-TAPS collaborations at MAMI [1]. This data has reached unprecedented levels of accuracy from threshold through to the $\\Delta$ resonance. Accompanying the experimental work, there has also been a series of publications studying the theory that show that, to go beyond an energy of $E_\\gamma=170$ MeV, it is necessary to include other aspects, in particular the $\\Delta (1232)$ as a degree of freedom [2] and possibly higher partial waves [3].

  17. Symmetry breaking phase transitions in the Aharony-Bergman-Jafferis-Maldacena theory with a finite U(1) chemical potential

    International Nuclear Information System (INIS)

    We consider the U(1) charged sector of ABJM theory at finite temperature, which corresponds to the Reissner-Nordstrom AdS black hole in the dual type IIA supergravity description. Including back-reaction to the bulk geometry, we show that phase transitions occur to a broken phase where SU(4) R-symmetry of the field theory is broken spontaneously by the condensation of dimension one or two operators. We construct the composite operators out of fields in ABJM theory and describe the phase transition with the dual gravity solutions. We show numerically and analytically that the relevant critical exponents for the dimension one operator agree precisely with those of mean field theory in the strongly coupled regime of the large N planar limit.

  18. The impact of priming on new technology appropriation: An extension of adaptive structuration theory

    OpenAIRE

    Comi, Alice; Eppler, Martin J.; Herrmann, Andreas

    2012-01-01

    In this paper we present a theoretical and methodological extension of Adaptive Structuration Theory (AST), as applicable to information systems (IS), by showing how technology appropriation can be influenced and measured. We address the questions of how people react to novel user interfaces – specifically, an interactive online product configurator – and if that reaction can be influenced through two priming mechanisms. To answer these questions, we experimentally assess if priming use...

  19. The Impact Of Higher Qualification?... (A New Theory on “Common Sense Deficiency”

    Directory of Open Access Journals (Sweden)

    M.Arulmani

    2014-06-01

    Full Text Available The Scientific research article focus that the “Common Sense domain” of Human Brain shall be considered subject to consistent deficiency due to impact of “SALT CONTENTS” deficiency rather than acquired higher Qualification and sometimes deviate brain system.

  20. Collective Impact: Theory versus Reality. Corridors of College Success Series. CCRC Research Brief. Number 61

    Science.gov (United States)

    Karp, Melinda Mechur; Lundy-Wagner, Valerie

    2016-01-01

    Collective impact is an increasingly popular approach to addressing persistent social problems. It takes a place-based systems approach to social change and compared with other forms of collaboration is meant to be more structured and strategic. Such an approach is intuitively appealing, and it has the support of stakeholders at the local level,…

  1. Impact of PCR for respiratory viruses on antibiotic use : Theory and practice

    NARCIS (Netherlands)

    van de Pol, Alma C.; Wolfs, Tom F. W.; Tacke, Carline E. A.; Uiterwaal, Cuno S. P.; Forster, Johannes; van Loon, Anton M.; Kimpen, Jan L. L.; Rossen, John W. A.; Jansen, Nicolaas J. G.

    2011-01-01

    RATIONALE FOR THE STUDY: Real-time polymerase chain reaction (PCR) for respiratory viruses is more sensitive, yet more expensive, than conventionally used direct immunofluorescence (DIF). We determined the impact of real-time PCR, additional to DIF, on antibiotic prescription in ventilated children

  2. Accounting Practitioners Reflect on Faculty Impact: Bridging the Gap between Theory and Practice

    Science.gov (United States)

    Johnson, Ryan

    2014-01-01

    A gap exists between the perception of accounting education in the classroom and accounting as it is practiced. This study explores qualitatively the perceptions and experiences of mid-career accounting professionals with respect to the impact of academic faculty on their careers in accounting. The study identifies a perception gap in the…

  3. Chemically Robust Carbon Particles in Peat from the Tunguska Impact Site

    Science.gov (United States)

    Hough, R. M.; Gilmour, I.; Newton, J.; Arden, J.; Pillinger, C. T.

    1995-09-01

    The Tunguska impact event of 1908 caused the destruction of a large forested area but left no impact crater. It was interpreted to have exploded in mid-air and thus would disperse material in a fireball over a wide geographical area. Several attempts have been made to locate particles associated with the impact in materials such as tree resin (1) and even in Antarctic snow (2). One of us (JN) attended an expedition to the Tunguska impact area and collected samples of peat from a depth of 60 cm which is thought to be the level in the peat which holds the impact horizon and indeed contains charred vegetation. The peat was subjected to standard demineralization procedures using mineral and oxidizing acids to destroy all but the most resistant mineral phases. An emphasis was placed on the chromic acid treatment to remove organic carbon as the peat was inevitably of extremely high organic content but perchloric acid was also used to oxidize graphite. The residue after treatment has subsequently been examined using a scanning electron microscope (Jeol JSM-820I at 30kv) with a Kevex system to obtain an energy dispersion scan and subjected to stepped combustion to determine the carbon abundance and isotopic composition. The SEM revealed the predominance in the residue of chromium containing phases possibly as a result of the extensive chromic acid treatments but several very pure carbon-rich particles were also observed. These carbon particles were anhedral and up to 15 micrometers in size. Due to the nature of the acid treatment performed upon this sample only a very robust form of carbon could survive and the most likely mineral is diamond. Further analyses using a transmission electron microscope and selected are electron diffraction will be performed to resolve the true mineralogy of these carbon particles. Stepped heating experiments on the acid resistant residue in conjunction with static mass spectrometry (3) has been used to give both carbon and nitrogen contents

  4. Simulating the Atmospheric Impact of Criegee Intermediates: Implementation of new understanding in atmospheric chemical mechanisms

    Science.gov (United States)

    Bloss, William; Newland, Mike; Rickard, Andrew; Vereecken, Luc; Evans, Mathew; Munoz, Amalia; Rodenas, Mila

    2016-04-01

    Unsaturated hydrocarbons - alkenes - account for about 90% of global VOC. Stabilized Criegee Intermediates (SCI) are thought to be formed in the atmosphere mainly from reactions of unsaturated hydrocarbons with ozone. SCI have been shown in laboratory and chamber experiments to rapidly oxidise SO2 and NO2, providing a potentially important gas phase oxidation route for these species in the atmosphere. They have also been implicated in the formation of aerosol and organic acids. However, the importance of SCI reactions with traces gases is critically dependent on the relative ratio of the rate constants for the reactions of the SCI with these and other trace gases, with H2O, and for unimolecular decomposition, which vary between SCIs, and between geometric isomers. The selection of reactions and rate constants is critically important in determining the calculated impact of SCI processes upon atmospheric composition and chemistry. Since the recent resurgence in interest in this chemistry, a number of model studies have been performed, with SCI mechanisms of varying comprehensiveness and accuracy, as the understanding of the community has evolved from new laboratory, theoretical and chamber studies, and field observations. Here we present an assessment of the dependence of modelled SCI abundance, behaviour and impacts upon the Criegee mechanism adopted, in the context of (a) the accepted status quo prior to the laboratory and field studies of Welz et al. and Mauldin et al., (b) changes to the SCI mechanism reflecting new kinetics for key bimolecular reactions, e.g. with SO2 and NO2; (c) emerging understanding of the interactions of SCI with water vapour and their unimolecular decomposition and (d) reactions with other atmospheric trace gases. The modelled SCI behaviour is compared with the results from recent chamber studies, and the resulting calculated SCI abundance and impacts evaluated for urban and forested atmospheric boundary layer scenarios.

  5. Impact of forest fire on physical, chemical and biological properties of soil: A review

    OpenAIRE

    Satyam Verma; Jayakumar, S.

    2012-01-01

    Forest fire is very common to all the ecosystems of the world. It affects both vegetation and soil. It is also helpful in maintaining diversity and stability of ecosystems. Effect of forest fire and prescribed fire on forest soil is very complex. It affects soil organic matter, macro and micro-nutrients, physical properties of soil like texture, colour, pH, Bulk Density as well as soil biota. The impact of fire on forest soil depends on various factors such as intensity of fire, fuel load and...

  6. Chemical effects and the impact to insulation debris filter cakes at ECCS upstream and downstream components

    International Nuclear Information System (INIS)

    Investigations regarding release, solution, transportation and deposit of corrosion products become important to reactor safety research for PWR, when considering the long-term behaviour of emergency core cooling systems (ECCS) during loss of coolant accidents (LOCA). The knowledge of corrosion processes in boric acid is necessary to evaluate the impact on insulation debris filter cakes in upstream (sump strainers) and downstream (reactor core) components and their influence on head loss and heat removal out of the core. Generic complex experiments determined the quantity of flow-induced, released corrosion products and their influences on head losses at filter cakes. (author)

  7. Immediate impact on the rim zone of cement based materials due to chemical attack

    International Nuclear Information System (INIS)

    Cement based materials are in their widespread application fields exposed to various aqueous environments. This can lead to serious chemical changes affecting the durability of the materials. In particular in the context of service life prediction a detailed knowledge of the reaction mechanisms is a necessary base for the evaluation of the aggressivity of an aqueous medium and this is deduced commonly from long term investigations. However, these processes start immediately at the material/water-interface, when a cementitious system comes into contact with an aqueous solution, altering here the chemical composition and microstructure. This rim zone represents the first hurdle that has to be overcome by an attacking aqueous solution. Therefore, the properties of the surface near area should be closely associated with the further course of deterioration processes by reactive transport. In this context short term exposure experiments with hardened cement paste over 4 and 48 h have been carried out with demineralized water, hard tap water and different sulfate solutions. In order to investigate immediate changes in the near-surface region, depth profile cuts have been performed on the cement paste samples by means of focused ion beam preparation techniques. A scanning beam of Gallium ions is applied to cut a sharp edge in the cement paste surface, providing insights into the composition and microstructure of the upper ten to hundred microns. Electron microscopic investigations on such a section of the rim zone, together with surface sensitive X-ray diffraction accompanied by a detailed characterization of the bulk composition confirm that the properties of the material/water interface are of relevance for the durability of cement based systems in contact with aqueous solutions. In this manner, focused ion beam investigations constitute auspicious tools to contribute to a more sophisticated understanding of the reaction mechanisms. - Highlights: • The chemical

  8. Immediate impact on the rim zone of cement based materials due to chemical attack

    Energy Technology Data Exchange (ETDEWEB)

    Schwotzer, M., E-mail: matthias.schwotzer@kit.edu [Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces (IFG), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Scherer, T. [Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology (INT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Gerdes, A. [Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces (IFG), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); University of Applied Sciences Karlsruhe, Institute for Prevention in Construction, Moltkestr. 30, D-76133 Karlsruhe (Germany)

    2015-01-15

    Cement based materials are in their widespread application fields exposed to various aqueous environments. This can lead to serious chemical changes affecting the durability of the materials. In particular in the context of service life prediction a detailed knowledge of the reaction mechanisms is a necessary base for the evaluation of the aggressivity of an aqueous medium and this is deduced commonly from long term investigations. However, these processes start immediately at the material/water-interface, when a cementitious system comes into contact with an aqueous solution, altering here the chemical composition and microstructure. This rim zone represents the first hurdle that has to be overcome by an attacking aqueous solution. Therefore, the properties of the surface near area should be closely associated with the further course of deterioration processes by reactive transport. In this context short term exposure experiments with hardened cement paste over 4 and 48 h have been carried out with demineralized water, hard tap water and different sulfate solutions. In order to investigate immediate changes in the near-surface region, depth profile cuts have been performed on the cement paste samples by means of focused ion beam preparation techniques. A scanning beam of Gallium ions is applied to cut a sharp edge in the cement paste surface, providing insights into the composition and microstructure of the upper ten to hundred microns. Electron microscopic investigations on such a section of the rim zone, together with surface sensitive X-ray diffraction accompanied by a detailed characterization of the bulk composition confirm that the properties of the material/water interface are of relevance for the durability of cement based systems in contact with aqueous solutions. In this manner, focused ion beam investigations constitute auspicious tools to contribute to a more sophisticated understanding of the reaction mechanisms. - Highlights: • The chemical

  9. Impact of organic carbon on weathering and chemical denudation of granular basalt

    Science.gov (United States)

    Dontsova, Katerina; Zaharescu, Dragos; Henderson, Whitney; Verghese, Sarah; Perdrial, Nicolas; Hunt, Edward; Chorover, Jon

    2014-08-01

    Bench-scale experiments were conducted to determine rates and patterns of coupled organic matter infusion and weathering in a San Francisco volcanic field (Flagstaff, AZ) basalt sample under experimentally-modeled biotic and abiotic condition and to inform larger-scale collaborative studies at the landscape evolution observatory (LEO), Biosphere 2 (Tucson, AZ), where the same basaltic media is being used in a synthetic hillslope experiment. We postulated that mineral transformations depend significantly on the presence of organic carbon compounds including dissolved natural organic matter (DOM), with organic C simultaneously imprinting the chemical and mineralogical properties of primary and secondary solids undergoing incongruent dissolution. The present work reports on solute releases from Flagstaff basalt (FB) along laboratory-controlled gradients in DOM type and concentration. Loamy sand textured FB was subjected to flow-through, saturated column dissolution experiments using influent solutions with and without DOM compounds. Solutions included Ponderosa pine forest soil O-horizon extracts at three target concentrations: 7, 35, and 70 mg L-1 C, malic acid (MA) solutions at 7, 35, 70, and 140 mg L-1 C, and a control without DOM but having comparable inorganic solution composition. Chemical denudation rates for FB dissolution products were calculated from the concentration difference between outflow and inflow solutions. In addition, changes in the composition of the solid phase over the course of the experiment were determined using X-ray diffraction (XRD), X-ray fluorescence (XRF), and selective dissolution (SE). Column experiments supported dissolution rates derived from the literature and indicated a potentially strong effect of plant-derived organic ligands on mineral dissolution congruency and secondary phase precipitation. Both malic acid and DOM enhanced basalt dissolution, with malic acid having larger effect on per unit C basis. The largest relative

  10. Current status of the impact theory for the terminal Cretaceous extinction

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, W.; Alvarez, L.W.; Asaro, F.; Michel, H.V.

    1982-06-01

    Iridium is depleted in the earth's crust relative to its normal solar system abundance. Several hundred measurements by at least seven laboratories have disclosed an iridium abundance anomaly at the Cretaceous-Tertiary (C-T) boundary in 36 sites worldwide. Discovery of the first iridium anomaly in non-marine sediments, by Charles Orth and his colleagues, shows that the iridium was not extracted from sea water. Sediment starvation and a nearby supernova have also been eliminated as possible sources. Impact of a large extraterrestrial object is now widely accepted as the best explanation of the iridium anomaly. Paleomagnetic reversal stratigraphy of four marine and five non-marine C-T boundary sections is consistent with simultaneous extinction worldwide, but does not prove it. Ultra-high-resolution stratigraphic studies at Caravaca, in southern Spain, by Jan Smit, give an unparalled record of the extinction of the planktic foraminifera and the associated geochemical patterns. Au/Ir and Pt/Ir ratios from two C-T boundary clays indicate a type I carbonaceous chondrite composition for the impacting object. Iridium anomalies are known from two other stratigraphic horizons, in each case associated with direct evidence for an extraterrestrial impact: in the Pliocene, with chondritic ablation debris, and in the late Eocene with microtektites. The C-T impact site has not been located. Two interesting candidate sites are the circular sea-floor features west of Portugal and the Deccan Traps of India. There is a 20% probability that impact occurred on sea floor that has subsequently been subducted. The killing mechanism has not yet been established, but both temperature changes and darkness due to atmospheric dust are probable contributors. Darkness would have lasted a few months, rather than our originally suggested few years.

  11. Agency Theory

    DEFF Research Database (Denmark)

    Linder, Stefan; Foss, Nicolai Juul

    2015-01-01

    Agency theory studies the problems and solutions linked to delegation of tasks from principals to agents in the context of conflicting interests between the parties. Beginning from clear assumptions about rationality, contracting, and informational conditions, the theory addresses problems of ex...... agency theory to enjoy considerable scientific impact on social science; however, it has also attracted considerable criticism....

  12. Agency Theory

    DEFF Research Database (Denmark)

    Linder, Stefan; Foss, Nicolai Juul

    Agency theory studies the problems and solutions linked to delegation of tasks from principals to agents in the context of conflicting interests between the parties. Beginning from clear assumptions about rationality, contracting and informational conditions, the theory addresses problems of ex...... agency theory to enjoy considerable scientific impact on social science; however, it has also attracted considerable criticism....

  13. IMPACT OF SPLITTING OF CHEMICAL DOSES IN C STAGE ON TOXICITY DURING PAPER PRODUCTION

    Directory of Open Access Journals (Sweden)

    Divya Prakash

    2014-09-01

    Full Text Available The laboratory generated spent bleach liquor from the chlorination stages of Bamboo pulp has been analysed both qualitatively and quantitatively (without washing and with washing for various chlorophenolics acids using gas chromatography. A number of chlorinated derivatives of phenols, catechols, guaiacols, syringaldehydes have been identified. The concentrations of various compounds identified have also been compared with the reported 96LC50 values. The results indicates that splitting of chlorine dose gives 47% lower formation of chlorinated phenolic compounds in without washing in splitting of chemical dose in C stage and the total chlorophenolic compounds decrease by 54% which is 7% more in comparison to chlorination stage (Dosage being splitted into two equal parts and no in between washing has taken place.

  14. Impact of radiation treatment on chemical, biochemical and sensory properties, and microbiological quality of mackerel

    Science.gov (United States)

    Pinter, Nino; Maltar-Strmečki, Nadica; Kozačinski, Lidija; Njari, Bela; Cvrtila Fleck, Željka

    2015-12-01

    The effect of gamma radiation on shelf-life of mackerel (Scomber scombrus) was studied. Changes in raw fish stored at 4 °C were investigated simultaneously, by performing sensory evaluation, chemical analysis (pH value and NH3 concentration), and biochemical analyses of histamine concentration and microbiological quality. Analyses showed that preservation by gamma irradiation prolonged the freshness and sustainability without any unintended sensory changes. Furthermore, increasing the dose during the 10 days of storage considerably reduced the concentration of histamine, but only slightly reduced the concentration of ammonia (NH3). Bacterial examinations showed that gamma radiation decreased the total number of bacteria. Our results indicated that the shelf-life of mackerel stored at 4 °C can be prolonged by irradiation with a dose of 3 kGy.

  15. Impact of Chemical Reaction on MHD Mixed Convection Heat and Mass Transfer Flow with Thermophoresis

    Directory of Open Access Journals (Sweden)

    Prabir Kumar KUNDU

    2014-02-01

    Full Text Available A mathematical model is analyzed in order to study the effects of chemical reaction and thermophoresis on MHD mixed convection boundary layer flow of an incompressible, electrically conducting fluid past a heated vertical permeable flat plate embedded in a uniform porous medium, by taking into account the radiative heat flux and variable suction. The governing partial differential equations are transformed into a set of coupled ordinary differential equations which are solved analytically using the regular perturbation technique. Numerical results for dimensionless velocity, temperature, concentration as well as the skin friction coefficient, Nusselt number and Sherwood number are presented through graphs and a table for pertinent parameters to show interesting aspects of the solution.doi:10.14456/WJST.2014.35

  16. Sr isotope evolution during chemical weathering of granites -- impact of relative weathering rates of minerals

    Institute of Scientific and Technical Information of China (English)

    MA; Yingjun

    2001-01-01

    [1]Ma, Y. J., Liu, C. Q., Geochemistry of strontium isotopes in the crust weathering system, Acta Mineralogica Sinica (in Chinese), 1998, 18(3): 350.[2]Ma, Y. J., Liu, C. Q., Using strontium isotopes to trace nutrient element circulation and hydrochemical evolution within an ecosystem, Advance in Earth Sciences (in Chinese), 1999, 14 (4): 377.[3]Brantley, S. L., Chesley, J. T., Stillings, L. L., Isotopic ratios and release rates of strontium from weathering feldspars, Geochim. Cosmochim. Acta, 1998, 62(9): 1493.[4]Blum, J. D., Erel, Y., A silicate weathering mechanism linking increases in marine 87Sr/86Sr with global glaciation, Nature, 1995, 373: 415.[5]Blum, J. D., Erel, Y., Rb-Sr isotope systematics of granitic soil chronosequence: The importance of biotite weathering, Geochim. Cosmochim. Acta, 1997, 61(15): 3193.[6]Bullen, T., Krabbenhoft, D., Kendall, C., Kinetic and mineralogic controls on the evolution of groundwater chemistry and 87Sr/86Sr in a sandy silicate aquifer, northern Wisconsin, USA, Geochim. Cosmochim. Acta, 1996, 60: 1807.[7]Bullen, T., White, A., Blum, A. et al., Chemical weathering of a soil chronosequence on granitoid alluvium: Ⅱminer-alogic and isotopic constraints on the behavior of strontium, Geochim. Cosmochim. Acta, 1997, 61: 291.[8]Blum, J. D., Erel, Y., Brown, K., 87Sr/86Sr ratios of Sierra Nevada stream waters: Implications for relative mineral weath-ering rates, Geochim. Cosmochim. Acta, 1993, 57: 5019.[9]Ma Yingjun, Trace element and strontium isotope geochemistry during chemical weathering, Ph. D. Dissertation, 1999, Institute of Geochemistry, Chinese Academy of Sciences.[10]Nesbitt, H. W., Markovics, G., Price, R. C., Chemical processes affecting alkalis and alkaline earths during continental weathering, Geochim. Cosmochim. Acta, 1980, 44: 1659.[11]Clauer, N., Strontium and argon isotopes in naturally weathered biotites, muscovites and feldspars, Chem. Geol., 1981, 31: 325.[12

  17. Inner Shell Definition and Absolute Hydration Free Energy of K+(aq) on the Basis of Quasi-chemical Theory and Ab Initio Molecular Dynamics

    CERN Document Server

    Rempe, S B; Pratt, L R; Rempe, Susan B.; Pratt, Lawrence R.

    2003-01-01

    K+(aq) ion is an integral component of many cellular processes, amongst which the most important, perhaps, is its role in transmitting electrical impulses along the nerve. Understanding its hydration structure and thermodynamics is crucial in dissecting its role in such processes. Her we address these questions using both the statistical mechanical quasi-chemical theory of solutions and ab initio molecular dynamics simulations. Simulations predict an interesting hydration structure for K+(aq): the population of about six (6) water molecules within the initial minimum of the observed g_{KO}(r) at infinite dilution involves four (4) inner-most molecules that the quasi-chemical theory suggests should be taken as the theoretical inner shell. The contribution of the 5th and 6th closest water molecules is observable as a distinct shoulder on the principal maximum of the g_{KO}(r). The quasi-chemical estimate of solvation free energy for the neutral pair KOH is also in good agreement with experiments.

  18. Impact of NLTE on research of early chemical enrichment of the dwarf galaxies

    Science.gov (United States)

    Mashonkina, Lyudmila

    2015-08-01

    The individual stars observed in the dwarf galaxies orbiting the Milky Way are presumably red giants. Their chemical abundances are commonly determined under the classical LTE assumption, despite its validity is questionable for atmospheres of giant, in particular, metal-poor stars. Exactly metal-poor objects are important for understanding the early chemical enrichment processes of the host galaxy and the onset of star formation. We selected a sample of the -4 Sex, and Fnx stars, with effective temperatures and surface gravities derived from the photometry and known distance (Jablonka et al. 2015; Tafelmeyer et al. 2010), the Fe I/Fe II ionisation equilibrium was found to be fulfilled, when applying a scaling factor of SH = 0.5 to the Drawinian rates of Fe+H collisions. Pronounced NLTE effects were calculated for lines of Na I and Al I resulting in up to 0.5 dex lower [Na/Fe] ratios and up to 0.65 dex higher [Al/Fe] ratios compared with the corresponding LTE values. For the six Scl stars, the scatter of data on Mg/Na is much smaller in NLTE, with the mean [Mg/Na] = 0.61 +- 0.11, than LTE, where [Mg/Na] = 0.42 +- 0.21. We computed a grid of the NLTE abundance corrections for an extensive list of the Ca I, Ti I-Ti II, and Fe I lines in the MARCS models of cool giants, 4000 K <= Teff <= 4750 K, 0.5 <= log g <= 2.5, -4 <= [M/H] <= 0.

  19. Chemical speciation and enzymatic impact of silver in antimicrobial fabric buried in soil.

    Science.gov (United States)

    Takeuchi, Satoshi; Hashimoto, Yohey; Yamaguchi, Noriko; Toyota, Koki

    2016-11-01

    This study investigated the impact of Ag in antibacterial fabric on soil enzymes in relation to solubility and speciation of Ag. Sections of Ag-containing sock fabric (1.0-1.5cm(2)) were incubated in soils with aerobic and anaerobic conditions and periodically determined activity of arylsulfatase, dehydrogenase and urease. Microscale distribution and speciation of Ag at the interface between socks and soil particles were investigated using micro-focused X-ray fluorescence (μ-XRF), and Ag speciation was determined using micro-focused X-ray absorption near edge structure (μ-XANES) spectroscopy. Results showed that the sock fabric consisted of elemental Ag and Ag2S. After 60-day exposure to soil, majority (50-90%) of Ag in sock did not undergo phase transformation and present as elemental Ag and Ag2S in aerobic and anaerobic conditions. A part of Ag in sock fabric was bound with soil colloids (<15%), depending on the distance from the edge of sock fabric. Soil enzyme activities were overall unaffected by Ag in sock textile after 60days of incubation, although a significant decrease in arylsulfatase activity was found only in the initial stage of soil incubation. Silver in the sock fabric is relatively stable and has little detrimental impacts on enzyme activity in ordinary soil conditions. PMID:27351904

  20. Chemical speciation and enzymatic impact of silver in antimicrobial fabric buried in soil.

    Science.gov (United States)

    Takeuchi, Satoshi; Hashimoto, Yohey; Yamaguchi, Noriko; Toyota, Koki

    2016-11-01

    This study investigated the impact of Ag in antibacterial fabric on soil enzymes in relation to solubility and speciation of Ag. Sections of Ag-containing sock fabric (1.0-1.5cm(2)) were incubated in soils with aerobic and anaerobic conditions and periodically determined activity of arylsulfatase, dehydrogenase and urease. Microscale distribution and speciation of Ag at the interface between socks and soil particles were investigated using micro-focused X-ray fluorescence (μ-XRF), and Ag speciation was determined using micro-focused X-ray absorption near edge structure (μ-XANES) spectroscopy. Results showed that the sock fabric consisted of elemental Ag and Ag2S. After 60-day exposure to soil, majority (50-90%) of Ag in sock did not undergo phase transformation and present as elemental Ag and Ag2S in aerobic and anaerobic conditions. A part of Ag in sock fabric was bound with soil colloids (<15%), depending on the distance from the edge of sock fabric. Soil enzyme activities were overall unaffected by Ag in sock textile after 60days of incubation, although a significant decrease in arylsulfatase activity was found only in the initial stage of soil incubation. Silver in the sock fabric is relatively stable and has little detrimental impacts on enzyme activity in ordinary soil conditions.

  1. The lack of foundation in the mechanism on which are based the physico-chemical theories for the origin of the genetic code is counterposed to the credible and natural mechanism suggested by the coevolution theory.

    Science.gov (United States)

    Di Giulio, Massimo

    2016-06-21

    I analyze the mechanism on which are based the majority of theories that put to the center of the origin of the genetic code the physico-chemical properties of amino acids. As this mechanism is based on excessive mutational steps, I conclude that it could not have been operative or if operative it would not have allowed a full realization of predictions of these theories, because this mechanism contained, evidently, a high indeterminacy. I make that disapproving the four-column theory of the origin of the genetic code (Higgs, 2009) and reply to the criticism that was directed towards the coevolution theory of the origin of the genetic code. In this context, I suggest a new hypothesis that clarifies the mechanism by which the domains of codons of the precursor amino acids would have evolved, as predicted by the coevolution theory. This mechanism would have used particular elongation factors that would have constrained the evolution of all amino acids belonging to a given biosynthetic family to the progenitor pre-tRNA, that for first recognized, the first codons that evolved in a certain codon domain of a determined precursor amino acid. This happened because the elongation factors recognized two characteristics of the progenitor pre-tRNAs of precursor amino acids, which prevented the elongation factors from recognizing the pre-tRNAs belonging to biosynthetic families of different precursor amino acids. Finally, I analyze by means of Fisher's exact test, the distribution, within the genetic code, of the biosynthetic classes of amino acids and the ones of polarity values of amino acids. This analysis would seem to support the biosynthetic classes of amino acids over the ones of polarity values, as the main factor that led to the structuring of the genetic code, with the physico-chemical properties of amino acids playing only a subsidiary role in this evolution. As a whole, the full analysis brings to the conclusion that the coevolution theory of the origin of the

  2. Using signal detection theory to test the impact of negative emotion on sub-clinical paranoia.

    Science.gov (United States)

    Westermann, Stefan; Lincoln, Tania M

    2010-06-01

    A novel experimental paradigm for measuring state paranoia by means of signal detection theory was evaluated. A liberal response bias, indicating the tendency to recognize facial expressions as threatening, was expected to reflect paranoia. Against theoretical expectations, heightened paranoia questionnaire scores were associated with a non-liberal bias, which was not affected by negative emotion per se. However, subsequent analyses revealed that, if anxious, participants with heightened paranoia adopted a comparatively more liberal response bias. These findings corroborate the eminent role of anxiety in paranoia and demonstrate that state paranoia can be captured with the presented paradigm.

  3. Triple-differential cross sections of helium for election impact by BBK theory

    International Nuclear Information System (INIS)

    The triple-differential cross sections for electron-impact ionization of helium in symmetric coplanar energy-sharing geometry were calculated at an incident energy range of 40-800 eV and an angle of 45 degree. The results were compared with those of the plane wave impulse approximation model. It was found that the present results give a better description for the experimental data

  4. Theory of hole initiated impact ionization in bulk zincblende and wurtzite GaN

    Science.gov (United States)

    Oǧuzman, Ismail H.; Bellotti, Enrico; Brennan, Kevin F.; Kolník, Ján; Wang, Rongping; Ruden, P. Paul

    1997-06-01

    In this article, the first calculations of hole initiated interband impact ionization in bulk zincblende and wurtzite phase GaN are presented. The calculations are made using an ensemble Monte Carlo simulation including the full details of all of the relevant valence bands, derived from an empirical pseudopotential approach, for each crystal type. The model also includes numerically generated hole initiated impact ionization transition rates, calculated based on the pseudopotential band structure. The calculations predict that both the average hole energies and ionization coefficients are substantially higher in the zincblende phase than in the wurtzite phase. This difference is attributed to the higher valence band effective masses and equivalently higher effective density of states found in the wurtzite polytype. Furthermore, the hole ionization coefficient is found to be comparable to the previously calculated electron ionization coefficient in zincblende GaN at an applied electric field strength of 3 MV/cm. In the wurtzite phase, the electron and hole impact ionization coefficients are predicted to be similar at high electric fields, but at lower fields, the hole ionization rate appears to be greater.

  5. Density functional theory analysis of the impact of steric interaction on the function of switchable polarity solvents.

    Science.gov (United States)

    McNally, Joshua S; Noll, Bruce; Orme, Christopher J; Wilson, Aaron D

    2015-06-01

    A density functional theory (DFT) analysis has been performed to explore the impact of steric interactions on the function of switchable polarity solvents (SPS) and their implications on a quantitative structure-activity relationship (QSAR) model previously proposed for SPS. An X-ray crystal structure of the N,N-dimethylcyclohexylammonium bicarbonate (Hdmcha) salt has been solved as an asymmetric unit containing two cation/anion pairs, with a hydrogen bonding interaction observed between the bicarbonate anions, as well as between the cation and anion in each pair. DFT calculations provide an optimized structure of Hdmcha that closely resembles experimental data and reproduces the cation/anion interaction with the inclusion of a dielectric field. Relaxed potential energy surface (PES) scans have been performed on Hdmcha-based computational model compounds, differing in the size of functional group bonded to the nitrogen center, to assess the steric impact of the group on the relative energy and structural properties of the compound. Results suggest that both the length and amount of branching associated with the substituent impact the energetic limitations on rotation of the group along the N-R bond and NC-R bond, and disrupt the energy minimized position of the hydrogen bonded bicarbonate group. The largest interaction resulted from functional groups that featured five bonds between the ammonium proton and a proton on a functional group with the freedom of rotation to form a pseudo six membered ring which included both protons.

  6. The impact of soil uptake on the global distribution of molecular hydrogen: chemical transport model simulation

    Directory of Open Access Journals (Sweden)

    H. Yashiro

    2011-07-01

    Full Text Available The global tropospheric distribution of molecular hydrogen (H2 and its uptake by the soil are simulated using a model called CHemical AGCM (atmospheric general circulation model for the Study of the Environment and Radiative forcing (CHASER, which incorporates a two-layered soil diffusion/uptake process component. The simulated distribution of deposition velocity over land is influenced by regional climate, and has a global average of 3.3×10−2 cm s−1. In the region north of 30° N, the amount of soil uptake shows a large seasonal variation corresponding to change in biological activity due to soil temperature and change in diffusion suppression by snow cover. In the temperate and humid regions in the mid- to low- latitudes, the uptake is mostly influenced by the soil air ratio, which controls the gas diffusivity in the soil. In the semi-arid regions, water stress and high temperatures contribute to the reduction of biological activity, as well as to the seasonal variation in the deposition velocity. A comparison with the observations shows that the model reproduces both the distribution and seasonal variation of H2 relatively well. The global burden and tropospheric lifetime of H2 are 150 Tg and 2.0 yr, respectively. The seasonal variation in H2 mixing ratios at the northern high latitudes is mainly controlled by a large seasonal change in the soil uptake. In the Southern Hemisphere, seasonal change in net chemical production and inter-hemispheric transport are the dominant causes of the seasonal cycle, while large biomass burning contributes significantly to the seasonal variation in the tropics and subtropics. Both observations and the model show large inter-annual variations, especially for the period 1997–1998, associated with large biomass burning in the tropics and at Northern Hemisphere high latitudes. The soil uptake shows relatively small inter-annual variability

  7. Driving frequency and Its impact on road rage offending and victimization: a view from opportunity theory.

    Science.gov (United States)

    Asbridge, Mark; Butters, Jennifer

    2013-01-01

    Road rage has been described as a key criminal justice and public health concern. Although research attention to this issue has expanded dramatically, most of this work has focused on the identification of predisposing individual factors. It is equally important to begin to assess those factors that may modify the likelihood of road rage including the broader structural opportunities that are connected with the propensity to be involved in a road rage incident. Drawing on opportunity theory, this article examines whether there is a relationship between increased opportunities to be involved in road rage and an increased likelihood of being a road rage victim or offender. The analysis is further extended to specifically test whether this relationship is linear, thereby examining the applicability of the opportunity saturation hypothesis. Using data from the Centre for Addiction and Mental Health (CAMH) Monitor, our findings support both the application of opportunity theory to understanding road rage and the presence of opportunity saturation. Although a clear relationship exists between kilometers driven and experiences of road rage, evidence emerged suggesting there may be a threshold whereby increased opportunities for road rage do not lead to road rage behavior.

  8. Understanding the impacts of allocation approaches during process-based life cycle assessment of water treatment chemicals.

    Science.gov (United States)

    Alvarez-Gaitan, Juan P; Peters, Gregory M; Short, Michael D; Schulz, Matthias; Moore, Stephen

    2014-01-01

    Chemicals are an important component of advanced water treatment operations not only in terms of economics but also from an environmental standpoint. Tools such as life cycle assessment (LCA) are useful for estimating the environmental impacts of water treatment operations. At the same time, LCA analysts must manage several fundamental and as yet unresolved methodological challenges, one of which is the question of how best to "allocate" environmental burdens in multifunctional processes. Using water treatment chemicals as a case study example, this article aims to quantify the variability in greenhouse gas emissions estimates stemming from methodological choices made in respect of allocation during LCA. The chemicals investigated and reported here are those most important to coagulation and disinfection processes, and the outcomes are illustrated on the basis of treating 1000 ML of noncoagulated and nondisinfected water. Recent process and economic data for the production of these chemicals is used and methodological alternatives for solving the multifunctionality problem, including system expansion and mass, exergy, and economic allocation, are applied to data from chlor-alkali plants. In addition, Monte Carlo simulation is included to provide a comprehensive picture of the robustness of economic allocation results to changes in the market price of these industrial commodities. For disinfection, results demonstrate that chlorine gas has a lower global warming potential (GWP) than sodium hypochlorite regardless of the technique used to solve allocation issues. For coagulation, when mass or economic allocation is used to solve the multifunctionality problem in the chlor-alkali facility, ferric chloride was found to have a higher GWP than aluminum sulfate and a slightly lower burden where system expansion or exergy allocation are applied instead. Monte Carlo results demonstrate that when economic allocation is used, GWP results were relatively robust and resilient

  9. Understanding the impacts of allocation approaches during process-based life cycle assessment of water treatment chemicals.

    Science.gov (United States)

    Alvarez-Gaitan, Juan P; Peters, Gregory M; Short, Michael D; Schulz, Matthias; Moore, Stephen

    2014-01-01

    Chemicals are an important component of advanced water treatment operations not only in terms of economics but also from an environmental standpoint. Tools such as life cycle assessment (LCA) are useful for estimating the environmental impacts of water treatment operations. At the same time, LCA analysts must manage several fundamental and as yet unresolved methodological challenges, one of which is the question of how best to "allocate" environmental burdens in multifunctional processes. Using water treatment chemicals as a case study example, this article aims to quantify the variability in greenhouse gas emissions estimates stemming from methodological choices made in respect of allocation during LCA. The chemicals investigated and reported here are those most important to coagulation and disinfection processes, and the outcomes are illustrated on the basis of treating 1000 ML of noncoagulated and nondisinfected water. Recent process and economic data for the production of these chemicals is used and methodological alternatives for solving the multifunctionality problem, including system expansion and mass, exergy, and economic allocation, are applied to data from chlor-alkali plants. In addition, Monte Carlo simulation is included to provide a comprehensive picture of the robustness of economic allocation results to changes in the market price of these industrial commodities. For disinfection, results demonstrate that chlorine gas has a lower global warming potential (GWP) than sodium hypochlorite regardless of the technique used to solve allocation issues. For coagulation, when mass or economic allocation is used to solve the multifunctionality problem in the chlor-alkali facility, ferric chloride was found to have a higher GWP than aluminum sulfate and a slightly lower burden where system expansion or exergy allocation are applied instead. Monte Carlo results demonstrate that when economic allocation is used, GWP results were relatively robust and resilient

  10. Mechano-chemical spinodal decomposition: A phenomenological theory of phase transformations in multi-component, crystalline solids

    CERN Document Server

    Rudraraju, Shiva; Garikipati, Krishna

    2015-01-01

    We present a new phenomenological treatment of phase transformations in multi-component crystalline solids driven by free energy density functions that are non-convex in mechanical and chemical variables. We identify the mechano-chemical spinodal as the region in strain-composition space where the free energy density function is non-convex. Our treatment describes diffusional phase transformations that are accompanied by symmetry breaking structural changes of the crystal unit cell due to mechanical instabilities in the mechano-chemical spinodal. This approach is relevant to phase transformations wherein the structural order parameters can be expressed as linear combinations of strains relative to a high-symmetry reference crystal. Because the local strains in an inhomogeneous, transforming microstructure can be finite, the elasticity problem must account for geometric nonlinearity. Furthermore, for physical consistency and mathematical well-posedness, we regularize the free energy density functions by interf...

  11. Chemical and toxicological characterization of sediments along a Colombian shoreline impacted by coal export terminals.

    Science.gov (United States)

    Caballero-Gallardo, Karina; Guerrero-Castilla, Angelica; Johnson-Restrepo, Boris; de la Rosa, Jesus; Olivero-Verbel, Jesus

    2015-11-01

    Extraction, transport and utilization of coal spread out coal dust. Nowadays, Colombia is an important producer of this mineral in South America, being the Santa Marta area one of the largest coal exporting ports in the country. The aim of this work was to assess the pollutants levels and toxicity of shoreline sediments from this place. 16 PAHs and 46 elements were measured in nine locations during dry and rainy seasons. HepG2 cells were exposed to 1% sediment extracts and mRNA expression evaluated for selected genes. PAHs levels were greater during the rainy season. The highest ∑PAHs (89.9 ng g(-1)) appeared at a site located around 300 m far from the coast line at close proximity to the area where coal is loaded into cargo vessels for international shipments, being naphthalene the most abundant PAH. At Santa Marta Bay port, ∑PAHs were 62.8 ng g(-1) and 72.8 ng g(-1) for dry and rainy seasons, respectively, with greatest levels for fluoranthene. Based on sediment standards, most stations have poor condition regarding Cr, but moderate contamination on Cu, Pb and Zn. Sediments from the port and coal transport sites, the most polluted by PAHs and metals, induced CYP1A1 and NQO1 during the dry season. Data showed the sediments from this shoreline have bioactive chemicals that determine their toxicological profile. PMID:26298075

  12. Impact of lignin and carbohydrate chemical structures on degradation reactions during hardwood kraft pulping processes

    Directory of Open Access Journals (Sweden)

    Ricardo B. Santos

    2013-02-01

    Full Text Available Most studies aimed at determining rates of hardwood delignification and carbohydrate degradation have focused on understanding the behavior of a single wood species. Such studies tend to determine either the delignification rate or the rate of carbohydrate degradation without examining the potential interactions resulting from related variables. The current study provides a comprehensive evaluation on both lignin and carbohydrate degradation during kraft pulping of multiple hardwood species. The kraft delignification rates of E. urograndis, E. nitens, E. globulus, sweet gum, maple, red oak, red alder, cottonwood, and acacia were obtained. Furthermore, the kinetics of glucan, xylan, and total carbohydrate dissolution during the bulk phase of the kraft pulping process for the above species were also investigated. The wide ranges of delignification and carbohydrate degradation rates were correlated to wood chemical characteristics. It appears that the S/G ratio and lignin-carbohydrate-complexes (LCCs are the main characteristics responsible for the differences in kraft pulping performance among the hardwoods studied.

  13. Impacts of chemical modification on the toxicity of diverse nanocellulose materials to developing zebrafish

    Science.gov (United States)

    Harper, Bryan J.; Clendaniel, Alicea; Sinche, Federico; Way, Daniel; Hughes, Michael; Schardt, Jenna; Simonsen, John; Stefaniak, Aleksandr B.

    2016-01-01

    Cellulose is an abundant and renewable resource currently being investigated for utility in nanomaterial form for various promising applications ranging from medical and pharmaceutical uses to mechanical reinforcement and biofuels. The utility of nanocellulose and wide implementation ensures increasing exposure to humans and the environment as nanocellulose-based technologies advance. Here, we investigate how differences in aspect ratio and changes to surface chemistry, as well as synthesis methods, influence the biocompatibility of nanocellulose materials using the embryonic zebrafish. Investigations into the toxicity of neutral, cationic and anionic surface functionalities revealed that surface chemistry had a minimal influence on the overall toxicity of nanocellulose materials. Higher aspect ratio cellulose nanofibers produced by mechanical homogenization were, in some cases, more toxic than other cellulose-based nanofibers or nanocrystals produced by chemical synthesis methods. Using fluorescently labeled nanocellulose we were able to show that nanocellulose uptake did occur in embryonic zebrafish during development. We conclude that the benign nature of nanocellulose materials makes them an ideal platform to systematically investigate the inherent surface features driving nanomaterial toxicity in order to create safer design principles for engineered nanoparticles. PMID:27468180

  14. Direct-to-consumer (DTC) antidepressant advertising and consumer misperceptions about the chemical imbalance theory of depression: the moderating role of skepticism.

    Science.gov (United States)

    Park, Jin Seong; Ahn, Ho-Young Anthony

    2013-01-01

    Based on a survey with members of an online consumer panel (N= 699), this study revealed that: (a) a substantial percentage of consumers held misperceptions about the chemical imbalance theory of depression; (b) personal and interpersonal experiences with depression positively related to such misperceptions; (c) overall, exposure to direct-to-consumer (DTC) antidepressant advertising did not significantly relate to misperceptions; and (d) DTC exposure magnified misperceptions when consumers were highly trustful of DTC advertising, whereas exposure diluted misperceptions when consumers were highly skeptical. Theoretical and practical implications of the research are discussed, especially in light of the social responsibility of DTC advertising. PMID:24308414

  15. Direct-to-consumer (DTC) antidepressant advertising and consumer misperceptions about the chemical imbalance theory of depression: the moderating role of skepticism.

    Science.gov (United States)

    Park, Jin Seong; Ahn, Ho-Young Anthony

    2013-01-01

    Based on a survey with members of an online consumer panel (N= 699), this study revealed that: (a) a substantial percentage of consumers held misperceptions about the chemical imbalance theory of depression; (b) personal and interpersonal experiences with depression positively related to such misperceptions; (c) overall, exposure to direct-to-consumer (DTC) antidepressant advertising did not significantly relate to misperceptions; and (d) DTC exposure magnified misperceptions when consumers were highly trustful of DTC advertising, whereas exposure diluted misperceptions when consumers were highly skeptical. Theoretical and practical implications of the research are discussed, especially in light of the social responsibility of DTC advertising.

  16. Optical properties of PM2.5 and the impacts of chemical compositions in the coastal city Xiamen in China.

    Science.gov (United States)

    Deng, Junjun; Zhang, Yanru; Hong, Youwei; Xu, Lingling; Chen, Yanting; Du, Wenjiao; Chen, Jinsheng

    2016-07-01

    Continuous in situ measurements of optical properties of fine aerosols (PM2.5) were conducted in the urbanized coastal city Xiamen in Southeast China from November 2013 to January 2014. PM2.5 samples were also collected and chemical compositions including organic carbon (OC), elemental carbon (EC) and water-soluble inorganic ions were determined to investigate the impacts of chemical compositions on aerosol optical properties. Average values of scattering coefficient (bscat), absorption coefficient (babs), extinction coefficient (bext) and single scattering albedo (SSA) were 164.0Mm(-1), 22.4Mm(-1), 187.0Mm(-1) and 0.88, respectively. bscat, babs and bext showed obvious bi-modal diurnal variations with high values in the morning and at night while low value in the early afternoon, whereas SSA exhibited an opposite diurnal variation. Average bscat and babs were largest in the wind direction of southwest and were larger with slower wind. babs was mainly affected by EC, while bscat was affected by ammonium, sulfate, nitrate and OC. The IMPROVE formula was applied to estimate bext based on the chemical species. Results shows that ammonium sulfate was the largest contributor, accounting for 36.4% of bext, followed by organic matter (30.6%), ammonium nitrate (20.1%), EC (9.0%) and sea salt (3.9%). The deterioration in visibility was mainly led by increases in secondary aerosols including sulfate and nitrate. Backward trajectories analysis showed that during the sampling period Xiamen was significantly affected by the air masses originating from the Northern and Northeastern areas. Air masses from the Northern associated with relative higher bext and less relative contribution from ammonium sulfate and more relative contribution from ammonium nitrate, organic matter and sea salt. PMID:27037888

  17. Assessing the Impact of Capture on Wild Animals: The Case Study of Chemical Immobilisation on Alpine Ibex.

    Directory of Open Access Journals (Sweden)

    Francesca Brivio

    Full Text Available The importance of capturing wild animals for research and conservation projects is widely shared. As this activity continues to become more common, the need to assess its negative effects increases so as to ensure ethical standards and the validity of research results. Increasing evidence has revealed that indirect (physiological and behavioural effects of capture are as important as direct risks (death or injury and that different capture methodologies can cause heterogeneous effects. We investigated the influence of chemical immobilisation on Alpine ibex (Capra ibex: during the days following the capture we collected data on spatial behaviour, activity levels of both males and females, and male hormone levels. Moreover, we recorded the reproductive status of each marked female during the breeding seasons of 15 years. Then, by several a priori models we investigated the effects of the capture taking into account biological factors and changes in environmental conditions. Our results showed that chemical immobilisation did not affect either spatial behaviour (for both males and females or male hormone levels, though both sexes showed reduced activity levels up to two days after the capture. The capture did not significantly affect the likelihood for a female to give birth in the following summer. Our findings highlighted the scarce impact of chemical immobilisation on ibex biology, as we detected alteration of activity levels only immediately after the capture if compared to the following days (i.e., baseline situation. Hence, the comparison of our findings with previous research showed that our methodology is one of the less invasive procedures to capture large mammals. Nonetheless, in areas characterised by high predator density, we suggest that animals released be carefully monitored for some hours after the capture. Moreover, researchers should avoid considering data collected during the first days after the manipulation in order to avoid

  18. Assessing the Impact of Capture on Wild Animals: The Case Study of Chemical Immobilisation on Alpine Ibex.

    Science.gov (United States)

    Brivio, Francesca; Grignolio, Stefano; Sica, Nicoletta; Cerise, Stefano; Bassano, Bruno

    2015-01-01

    The importance of capturing wild animals for research and conservation projects is widely shared. As this activity continues to become more common, the need to assess its negative effects increases so as to ensure ethical standards and the validity of research results. Increasing evidence has revealed that indirect (physiological and behavioural) effects of capture are as important as direct risks (death or injury) and that different capture methodologies can cause heterogeneous effects. We investigated the influence of chemical immobilisation on Alpine ibex (Capra ibex): during the days following the capture we collected data on spatial behaviour, activity levels of both males and females, and male hormone levels. Moreover, we recorded the reproductive status of each marked female during the breeding seasons of 15 years. Then, by several a priori models we investigated the effects of the capture taking into account biological factors and changes in environmental conditions. Our results showed that chemical immobilisation did not affect either spatial behaviour (for both males and females) or male hormone levels, though both sexes showed reduced activity levels up to two days after the capture. The capture did not significantly affect the likelihood for a female to give birth in the following summer. Our findings highlighted the scarce impact of chemical immobilisation on ibex biology, as we detected alteration of activity levels only immediately after the capture if compared to the following days (i.e., baseline situation). Hence, the comparison of our findings with previous research showed that our methodology is one of the less invasive procedures to capture large mammals. Nonetheless, in areas characterised by high predator density, we suggest that animals released be carefully monitored for some hours after the capture. Moreover, researchers should avoid considering data collected during the first days after the manipulation in order to avoid biased

  19. Probing the solvent shell with 195Pt chemical shifts: density functional theory molecular dynamics study of Pt(II) and Pt(IV) anionic complexes in aqueous solution.

    Science.gov (United States)

    Truflandier, Lionel A; Autschbach, Jochen

    2010-03-17

    Ab initio molecular dynamics (aiMD) simulations based on density functional theory (DFT) were performed on a set of five anionic platinum complexes in aqueous solution. (195)Pt nuclear magnetic shielding constants were computed with DFT as averages over the aiMD trajectories, using the two-component relativistic zeroth-order regular approximation (ZORA) in order to treat relativistic effects on the Pt shielding tensors. The chemical shifts obtained from the aiMD averages are in good agreement with experimental data. For Pt(II) and Pt(IV) halide complexes we found an intermediate solvent shell interacting with the complexes that causes pronounced solvent effects on the Pt chemical shifts. For these complexes, the magnitude of solvent effects on the Pt shielding constant can be correlated with the surface charge density. For square-planar Pt complexes the aiMD simulations also clearly demonstrate the influence of closely coordinated non-equatorial water molecules on the Pt chemical shift, relating the structure of the solution around the complex to the solvent effects on the metal NMR chemical shift. For the complex [Pt(CN)(4)](2-), the solvent effects on the Pt shielding constant are surprisingly small. PMID:20166712

  20. Studying Human Resource Information Systems Implementation using Adaptive Structuration Theory: The Case of an HRIS Implementation at Dow Chemical Company

    NARCIS (Netherlands)

    Ruel, Huub; Bondarouk, Tanya; Ruel, Huub; Guiderdoni-Jourdain, Karine; Oiry, Ewan

    2009-01-01

    Research on Human Resource Information Systems (HRIS) implementation lacks theoretical depth and richness. For that reason this paper applies a theory to HRIS implementation developed by Gerardine DeSanctis and Marshal Scott Poole originally for studying information systems implementation, namely Ad

  1. Impact of flavor and Higgs physics on theories beyond the standard model

    Energy Technology Data Exchange (ETDEWEB)

    Casagrande, Sandro

    2013-02-13

    Quantum effects of physics beyond the Standard Model receive strong indirect constraints from precisely measured collider observables. In the conceptual part of this thesis, we apply the generic relations between particle interactions in perturbatively unitary theories to calculate one-loop amplitudes for flavor physics. We provide template results applicable for any model of this class. We also investigate example models that are partly and such that are not perturbatively unitary: the Littlest Higgs model and Randall-Sundrum models. The latter have a unique coupling structure, which we cover exhaustively. We find strong constraints on the Randall-Sundrum models and numerically compare those from flavor, electroweak precision, and Higgs physics by performing detailed parameter scans. We observe interesting correlations between flavor observables, and we find that constraints from Higgs production and decays are already competitive.

  2. Understanding the Impact of User Frustration Intensities on Task Performance Using the OCC Theory of Emotions

    Science.gov (United States)

    Washington, Gloria

    2012-01-01

    Have you heard the saying "frustration is written all over your falce"? Well this saying is true, but that is not the only place. Frustration is written all over your face and your body. The human body has various means to communicate an emotion without the utterance of a single word. The Media Equation says that people interact with computers as if they are human: this includes experiencing frustration. This research measures frustration by monitoring human body-based measures such as heart rate, posture, skin temperature. and respiration. The OCC Theory of Emotions is used to separate frustration into different levels or intensities. The results of this study showed that individual intensities of frustration exist, so that task performance is not degraded. Results from this study can be used by usability testers to model how much frustration is needed before task performance measures start to decrease.

  3. Impact of forest fire on physical, chemical and biological properties of soil: A review

    Directory of Open Access Journals (Sweden)

    Satyam Verma

    2012-09-01

    Full Text Available Forest fire is very common to all the ecosystems of the world. It affects both vegetation and soil. It is also helpful in maintaining diversity and stability of ecosystems. Effect of forest fire and prescribed fire on forest soil is very complex. It affects soil organic matter, macro and micro-nutrients, physical properties of soil like texture, colour, pH, Bulk Density as well as soil biota. The impact of fire on forest soil depends on various factors such as intensity of fire, fuel load and soil moisture. Fire is beneficial as well as harmful for the forest soil depending on its severity and fire return interval. In low intensity fires, combustion of litter and soil organic matter increase plant available nutrients, which results in rapid growth of herbaceous plants and a significant increase in plant storage of nutrients. Whereas high intensity fires can result into complete loss of soil organic matter, volatilization of N, P, S, K, death of microbes, etc. Intense forest fire results into formation of some organic compounds with hydrophobic properties, which results into high water repellent soils. Forest fire also causes long term effect on forest soil. The purpose of this paper is to review the effect of forest fire on various properties of soil, which are important in maintaining healthy ecosystem.

  4. Reactive hydro- end chlorocarbons in the troposphere and lower stratosphere : sources, distributions, and chemical impact

    Science.gov (United States)

    Scheeren, H. A.

    2003-09-01

    The work presented in this thesis focuses on measurements of chemical reactive C2 C7 non-methane hydrocarbons (NMHC) and C1 C2 chlorocarbons with atmospheric lifetimes of a few hours up to about a year. The group of reactive chlorocarbons includes the most abundant atmospheric species with large natural sources, which are chloromethane (CH3Cl), dichloromethane (CH2Cl2), and trichloromethane (CHCl3), and tetrachloroethylene (C2Cl4) with mainly anthropogenic sources. The NMHC and chlorocarbons are present at relatively low quantities in our atmosphere (10-12 10-9 mol mol-1 of air). Nevertheless, they play a key role in atmospheric photochemistry. For example, the oxidation of NMHC plays a dominant role in the formation of ozone in the troposphere, while the photolysis of chlorocarbons contributes to enhanced ozone depletion in the stratosphere. In spite of their important role, however, their global source and sinks budgets are still poorly understood. Hence, this study aims at improving our understanding of the sources, distribution, and chemical role of reactive NMHC and chlorocarbons in the troposphere and lower stratosphere. To meet this aim, a comprehensive data set of selected C2 C7 NMHC and chlorocarbons has been analyzed, derived from six aircraft measurement campaigns with two different jet aircrafts (the Dutch TUD/NLR Cessna Citation PH-LAB, and the German DLR Falcon) conducted between 1995 and 2001 (STREAM 1995 and 1997 and 1998, LBA-CLAIRE 1998, INDOEX 1999, MINOS 2001). The NMHC and chlorocarbons have been detected by gas-chromatography (GC-FID/ECD) in pre-concentrated whole air samples collected in stainless steel canister on-board the measurement aircrafts. The measurement locations include tropical (Maldives/Indian Ocean and Surinam), midlatitude (Western Europe and Canada) and polar regions (Lapland/northern Sweden) between the equator to about 70ºN, covering different seasons and pollution levels in the troposphere and lower stratosphere. Of

  5. Roles of Chemical Complexity and Evolutionary Theory in Some Hepatic and Intestinal Enzymatic Systems in Chemical Reproducibility and Clinical Efficiency of Herbal Derivatives

    Directory of Open Access Journals (Sweden)

    Francesco Di Pierro

    2014-01-01

    Full Text Available Despite the great marketing success, most physicians attribute poor efficacy to herbals. This perception is due to two situations that are an integral part of the herbal topic. The first is the poor phytochemical reproducibility obtained during the production process of herbal extracts, as herbal extracts are not always standardized in the whole manufacturing process, but only in their titer. The second problem is linked to the evolution of important enzymatic systems: cytochromes and ABC proteins. They are both enzyme classes with detoxifying properties and seem to have evolved from the molecular mould provided by active plant substances. During the evolution, as still happens today, polyphenols, saponins, terpenes, and alkaloids were ingested together with food. They do not possess any nutritional value but seem to be provided with a potential pharmacological activity. Cytochromes and ABC proteins, which evolved over time to detoxify food from vegetable chemical “actives,” now seem to limit the action of herbal derivatives. The comprehension of these 2 events may explain the origin of the widespread scepticism of physicians about herbal medicine and suggests that, after correct herbal standardization, use of antagonists of cytochromes and ABC systems will make it possible to recover their pharmacological potential.

  6. Evaluating the impact of a fluoropolymer plant on a river macrobenthic community by a combined chemical, ecological and genetic approach.

    Science.gov (United States)

    Rusconi, Marianna; Marziali, Laura; Stefani, Fabrizio; Valsecchi, Sara; Bettinetti, Roberta; Mazzoni, Michela; Rosignoli, Federica; Polesello, Stefano

    2015-12-15

    Effect-based monitoring is a recommended approach suggested in European Guidelines to assess the response of ecosystem affected by a pollution source, considering the effects at community, population, individual but also at suborganism level. A combined chemical, ecological and genetic approach was applied in order to assess the impact of a fluoropolymer plant on the macrobenthic community of the Northern Italian river Bormida (Piedmont region). The macrobenthic community living downstream of the industrial discharge was chronically exposed to a mixture of perfluoroalkyl substances (PFAS), with perfluorooctanoic acid as the main compound, at concentrations up to several μgL(-1). Ecological assessment proved that the downstream community was not substantially different from that living upstream of the pollution source. The impact on community is not quantifiable with the traditional monitoring methods used for ecological classification under European regulation because macrobenthic communities showed only slight differences in their structure. In order to highlight effects on genetic variability of the native population, a subcellular analysis by using the AFLP (Amplified Fragment Length Polymorphism) genetic technique was applied to genotype of individuals of a selected species (Hydropsyche modesta, Trichoptera) collected in the two sampling sites. Percentage of variation between the two populations was 6.8%, a threshold compatible with a genetic drift induced in the downstream population. The genetic study carried out in field identified a significant divergence between exposed and non-exposed populations, but at present it is not possible to associate this divergence to a specific effect induced by PFAS.

  7. Small Open Chemical Systems Theory: Its Implications to Darwinian Evolution Dynamics, Complex Self-Organization and Beyond

    International Nuclear Information System (INIS)

    The study of biological cells in terms of mesoscopic, nonequilibrium, nonlinear, stochastic dynamics of open chemical systems provides a paradigm for other complex, self-organizing systems with ultra-fast stochastic fluctuations, short-time deterministic nonlinear dynamics, and long-time evolutionary behavior with exponentially distributed rare events, discrete jumps among punctuated equilibria, and catastrophe. (general)

  8. DETERMINATION OF CHEMICAL CLASSES FROM MASS SPECTRA OF TOXIC ORGANIC COMPOUNDS BY SIMCA PATTERN RECOGNITION AND INFORMATION THEORY

    Science.gov (United States)

    The low resolution mass spectra of a set of 78 toxic volatile organic compounds were examined for information concerning chemical classes. These compounds were predominately chloro- and/or bromoaromatics, -alkanes, or -alkenes, which are routinely sought at trace levels in ambien...

  9. Chemical restraint: "Pharmakologische Ruhigstellung" zum Management aggressiven Verhaltens im stationären Bereich in Theorie und Praxis

    OpenAIRE

    Libal, Gerhard; Plener, Paul L; Fegert, Jörg M; Kölch, Michael

    2006-01-01

    "Chemical restraint" oder "Pharmakologische Ruhigstellung" (PR) ist eine wichtige Intervention beim Management von aggressiven Verhaltensweisen von stationär behandelten Kindern und Jugendlichen. PR sollte ausschließlich im Rahmen eines standardisierten Interventionsplanes zur Anwendung kommen. Die Grundprinzipien eines solchen Zugangs sind transparente Vereinbarungen mit allen Beteiligten zur schnellen, sicheren und personenunabhängigen Reduktion des Verhaltens, ohne dass dabei Folges...

  10. Measuring the Impact of Financial Intermediation: Linking Contract Theory to Econometric Policy Evaluation.

    Science.gov (United States)

    Townsend, Robert M; Urzua, Sergio S

    2009-09-01

    We study the impact that financial intermediation can have on productivity through the alleviation of credit constraints in occupation choice and/or an improved allocation of risk, using both static and dynamic structural models as well as reduced form OLS and IV regressions. Our goal in this paper is to bring these two strands of the literature together. Even though, under certain assumptions, IV regressions can recover accurately the true model-generated local average treatment effect, these are quantitatively different, in order of magnitude and even sign, from other policy impact parameters (e.g., ATE and TT). We also show that laying out clearly alternative models can guide the search for instruments. On the other hand adding more margins of decision, i.e., occupation choice and intermediation jointly, or adding more periods with promised utilities as key state variables, as in optimal multi-period contracts, can cause the misinterpretation of IV as the causal effect of interest. PMID:20436953

  11. Decoupling in order to reduce the negative environmental impact from transport logistics. From theory to reality

    International Nuclear Information System (INIS)

    This report deals with the issue of decoupling from a bottom-up approach and thereby works as a complementary report to 'A closer Look at Road Freight Transport and Economic Growth in Sweden' published by the Swedish Environmental Protection Agency. The freight transport logistics market is steadily growing in Sweden and the EU. Between 1990 and 2002 the growth in Sweden was 15 % and in EU15 33 %. The increase has primarily occurred within road freight. Economics of scale and low cost for transport logistics services drives centralisation both within trade and manufacturing. This leads to an increase of the transport work. The objective of this report is to describe decoupling from a business perspective. We have therefore focused on industrial sectors that are the largest drivers of transportation demand. In addition we have included the most relevant providers of transport services. In brief this means - Buyers of transport logistics: Clothing, Furniture, Pulp and paper, Oil and energy, Steel, Mechanical industry, Fast moving goods, and Construction. As sellers of transport logistics services we have focused on: Road transport, Rail transport, Sea transport, and Forwarders. During the work we have ended up in a broad perspective when defining decoupling. In general we work with the concept of decoupling defined as 'breaking the connection between the environmentally negative impacts from transport logistics and economic growth'. The negative impacts we include are: Resource use, Climate, Nature, Health, and Accidents. Our focus is a European perspective from a Swedish platform and our time perspective is from relatively narrow to 2020. The business sector raises doubt on the idea of decoupling transport work and GNP. They are however more positive when discussing decoupling economic growth from negative environmental impacts. When analysing the underlying factors for this development we can se a tremendous growth in the global trade. the paper discuses how

  12. Chemical Transport and Reduced-Form Models for Assessing Air Quality Impacts of Current and Future Energy Scenarios

    Science.gov (United States)

    Adams, P. J.

    2015-12-01

    Though essential for informed decision-making, it is challenging to estimate the air quality and public health impacts associated with current and future energy generation scenarios because the analysis must address the complicated atmospheric processes that air pollutants undergo: emissions, dispersion, chemistry, and removal. Employing a chemical transport model (CTM) is the most rigorous way to address these atmospheric processes. However, CTMs are expensive from a computational standpoint and, therefore, beyond the reach of policy analysis for many types of problems. On the other hand, previously available reduced-form models used for policy analysis fall short of the rigor of CTMs and may lead to biased results. To address this gap, we developed the Estimating Air pollution Social Impacts Using Regression (EASIUR) method, which builds parameterizations that predict per-tonne social costs and intake fractions for pollutants emitted from any location in the United States. Derived from a large database of tagged CTM simulations, the EASIUR method predicts social costs almost indistinguishable from a full CTM but with negligible computational requirements. We found that the average mortality-related social costs from inorganic PM2.5 and its precursors in the United States are 150,000-180,000/t EC, 21,000-34,000/t SO2, 4,200-15,000/t NOx, and 29,000-85,000/t NH3. This talk will demonstrate examples of using both CTMs and reduced-form models for assessing air quality impacts associated with current energy production activities as well as a future deployment of carbon capture and sequestration.

  13. Food surveys for assessing chemical and dosimetric impacts near industrial sites

    International Nuclear Information System (INIS)

    Estimating the ingestion of potentially contaminated foodstuffs around conventional and nuclear industrial sites requires data about the food practices and eating habits of the local residents, especially the consumption of locally- and home-produced food. The IRSN thus chose to conduct surveys about these practices in the vicinity of nuclear sites. Their methodology was based on previous surveys near nuclear sites. In 2004, in partnership with AREVA and BEGEAT, the French Institute for Radioprotection and Nuclear Safety studied the eating habits of the residents of Bollene, near the Tricastin plant (Rhone Valley), with the aim of improving the quantification of the plant's potential health impacts. Based on these studies and as part of the SENSIB project to characterize vulnerability to nuclear risks, we developed and tested a survey protocol during the summer 2008, around the Chinon nuclear plant, in collaboration with EDF. The protocol is currently being tested around the Marcoule nuclear plant, in collaboration with the CEA. The aim was to optimize the feasibility and the reproducibility of the approach, while losing none of the robustness of the results. The data obtained made it possible to evaluate daily food intake values for individuals and to assess the rates of consumption of locally-grown products for many food categories. The data showed the existence of local population groups with very high rates of locally-grown food consumption - over 90 % of certain food products. This comparative study thus shows the significant variability of eating habits in the French population and proposes a reproducible approach to evaluating realistic indicators of potentially risky dietary habits. (authors)

  14. Health Impacts Estimation of Mineralogical and Chemical Characterization of Suspended Atmospheric Particles over the East Desert

    Directory of Open Access Journals (Sweden)

    U. A. Rahoma

    2010-01-01

    Full Text Available Problem statement: The small size fraction of aerosols, measured as PM10 and PM2.5, rather than the larger particles, is considered to be responsible for most of the health effects. Such particles have a relatively long residence time in the atmosphere and can therefore travel over long distances. Hence, a large portion of ambient concentrations of PM10 and in particular of particles with an aerodynamic diameter less than 2.5 µm (PM2.5, can be attributed to long range trans boundary air pollution or to other remote sources. The estimates of exposure and of health effects are based on a number of uncertain assumptions and data sets, as described in previous article. Approach: In industrialized Middle East countries, the daily deposition of PM10 particles in the lungs is roughly 250 µg day-1, which represents a small dose in terms of traditional toxicology studies. Studies of PM10 have considered this total material but have not asked how much its chemical or physical characteristics contribute to its total toxicity. Results: This article focuses on the description of the present knowledge on PM10 concentration fields and predominant sources contributing to PM10 from long range transport of pollution. PM10 is a complex mixture of many known and unknown components; therefore, a short introduction on the composition of PM10 is given. The studies denote to the African dust from mean PM10 levels background levels are still 5-10 mg m3 higher in the Eastern Basin (EMB when compared with those in the Western (WMB, mainly due to the higher anthropogenic and sea spray loads. Conclusion: As regards for the seasonal trends, these are largely driven by the occurrence of African dust events, resulting in a spring-early summer maximum over the EMB and a clear summer maximum in the WMB, although in this later region the recirculation of aged air masses play an important role. Furthermore, a marked seasonal trend is still evident when subtracting the African

  15. The effect of wetting and drying cycles on soil chemical composition and their impact on bulk density evaluation

    International Nuclear Information System (INIS)

    The gamma-ray attenuation technique has been applied successfully in several areas of knowledge such as medicine, industry, chemistry, biology, agriculture and so on. Before the technique application it is important to know the probability of gamma photons interaction with the matter. The linear attenuation coefficient (k) measures the probability per unit length of a photon to be absorbed or scattered while interacting with a sample. k represents the sum of several individual attenuation coefficients due mainly to the photoelectric absorption, coherent and incoherent scatterings and pair production. Soil is characterized as a three phase system composed by solid, liquid and gaseous phases. It is known that for a given photon energy the mass attenuation coefficient (μ) is directly related to the chemical composition of the soil. As a consequence by using the mixture rule, in which (μ) is calculated by adding the products of mass attenuation coefficients and the contents of the chemical components of the soil, it is possible to obtain a theoretical (μ) value. A possible cause of chemical composition changes in soil is the application of repeated wetting and drying (W-D) cycles. Another consequence of these changes in the chemical composition of the soil can be alterations in its (μ). This result can affect how well the gamma-ray attenuation or computed tomography (CT) techniques can determine soil bulk density (ds) or porosity (φ) when samples are submitted to W-D cycles. In this work the soil elemental (oxides) composition variation of three Brazilian soils submitted to the application of W-D cycles was measured in order to evaluate possible changes in the calculated μ as a function of the cycles. Measurements of μ by using radioactive sources of 241Am and 137Cs were also performed. Gamma-ray CT was used as a tool to evaluate the impact of changes in μ induced by the cycles in determinations of ds. The measured and calculated values of μ presented good

  16. An application of the theory of planned behavior to examine the impact of classroom inclusion on elementary school students.

    Science.gov (United States)

    Campbell, Michael

    2010-05-01

    Classroom inclusion serves as the most discussed service delivery model in the debate over the most appropriate way to provide education for students with disabilities. Integrating students with disabilities with nondisabled peers may increase attitudes of acceptance, but the literature also indicates that placement alone does not yield an increase in interaction between these two groups of peers (Brinker & Thorpe, 1986; Fryexe & Kennedy, 1995; Kennedy, Shulka, & Fryxell, 1997). This study investigated the impact of classroom inclusion on nondisabled students. Using survey research methods and guided by the Theory of Planned Behavior (Aizen, I. [1985]. From intentions to actions: A theory of planned behavior. In J. Kuhl & J. Beckman [Eds.], Action-control: From cognition to behavior [pp. 11-39]. Heidelberg: Springer), 593 responses were obtained from a convenience sample of 936 third, fourth, and fifth grade students and their parents from 52 classrooms spread across six different schools. Survey results were also collected from these students' parents and their teachers and used to add a richer depth to the data analysis. Implications for policy and practice are drawn. Limitations and recommendations for future research are also indicated. PMID:20526942

  17. Extension of a Kinetic-Theory Approach for Computing Chemical-Reaction Rates to Reactions with Charged Particles

    Science.gov (United States)

    Liechty, Derek S.; Lewis, Mark J.

    2010-01-01

    Recently introduced molecular-level chemistry models that predict equilibrium and nonequilibrium reaction rates using only kinetic theory and fundamental molecular properties (i.e., no macroscopic reaction rate information) are extended to include reactions involving charged particles and electronic energy levels. The proposed extensions include ionization reactions, exothermic associative ionization reactions, endothermic and exothermic charge exchange reactions, and other exchange reactions involving ionized species. The extensions are shown to agree favorably with the measured Arrhenius rates for near-equilibrium conditions.

  18. Impact of ancient charcoal kilns on chemical properties of several forest soils after 2 centuries

    Science.gov (United States)

    Dufey, Joseph; Hardy, Brieuc; Cornelis, Jean-Thomas

    2014-05-01

    negative charge of charcoal results from surface oxidation processes over time. This charge varies over quite a wide range of values according to soil type, which might be explained by the nature of the charred wood. The surface soil horizons at kiln site show a completely desaturated exchange complex, comparable to the reference soils. However, the raise of the base saturation in the underlying horizons reflects the past liming effect of ashes produced by wood charring that has been completely erased from the topsoil in 200 years. Exchangeable K+ in the topsoil layers of kiln sites is very low, which can be related to an enhanced selectivity for Mg++ and Ca++ on the exchange complex of old charred material. Similarly, very little Pav is extracted from charcoal-enriched horizons, suggesting that Pav is either reduced in quantity or in availability. Our data clearly highlight the long-term effect of the accumulation of charred material on the evolution of soil chemical properties due to charcoal ageing and nutrient leaching.

  19. How social evolution theory impacts our understanding of development in the social amoeba Dictyostelium.

    Science.gov (United States)

    Strassmann, Joan E; Queller, David C

    2011-05-01

    Dictyostelium discoideum has been very useful for elucidating principles of development over the last 50 years, but a key attribute means there is a lot to be learned from a very different intellectual tradition: social evolution. Because Dictyostelium arrives at multicellularity by aggregation instead of through a single-cell bottleneck, the multicellular body could be made up of genetically distinct cells. If they are genetically distinct, natural selection will result in conflict over which cells become fertile spores and which become dead stalk cells. Evidence for this conflict includes unequal representation of two genetically different clones in spores of a chimera, the poison-like differentiation inducing factor (DIF) system that appears to involve some cells forcing others to become stalk, and reduced functionality in migrating chimeras. Understanding how selection operates on chimeras of genetically distinct clones is crucial for a comprehensive view of Dictyostelium multicellularity. In nature, Dictyostelium fruiting bodies are often clonal, or nearly so, meaning development will often be very cooperative. Relatedness levels tell us what benefits must be present for sociality to evolve. Therefore it is important to measure relatedness in nature, show that it has an impact on cooperation in the laboratory, and investigate genes that Dictyostelium uses to discriminate between relatives and non-relatives. Clearly, there is a promising future for research at the interface of development and social evolution in this fascinating group.

  20. Different Models Used to Interpret Chemical Changes: Analysis of a Curriculum and Its Impact on French Students' Reasoning

    Science.gov (United States)

    Kermen, Isabelle; Meheut, Martine

    2009-01-01

    We present an analysis of the new French curriculum on chemical changes describing the underlying models and highlighting their relations to the empirical level. The authors of the curriculum introduced a distinction between the chemical change of a chemical system and the chemical reactions that account for it. We specify the different roles of…

  1. The Nature of the Chemical Process. 1. Symmetry Evolution – Revised Information Theory, Similarity Principle and Ugly Symmetry

    OpenAIRE

    Shu-Kun Lin

    2001-01-01

    Abstract: Symmetry is a measure of indistinguishability. Similarity is a continuous measure of imperfect symmetry. Lewis' remark that “gain of entropy means loss of information†defines the relationship of entropy and information. Three laws of information theory have been proposed. Labeling by introducing nonsymmetry and formatting by introducing symmetry are defined. The function L ( L=lnw, w is the number of microstates, or the sum of entropy and information, L=S+I) of the univers...

  2. What economic theory tells us about the impacts of reducing food losses and/or waste: implications for research, policy and practice

    OpenAIRE

    Rutten, M.M.

    2013-01-01

    Background - Whereas the prevalence of hunger and food insecurity is often cited as a motivation for reducing losses and waste in agriculture and food systems, the impacts of such reduction on food security and the wider economy have not yet been investigated. This paper gives insights into these effects, the factors of influence, and derives implications for applied research, policy and practice. Methods - We used economic theory to analyse the impacts of food loss reductions on the supply s...

  3. Service Undone: A Grounded Theory of Strategically Constructed Silos and Their Impact on Customer-Company Interactions from the Perspective of Retail Employees

    OpenAIRE

    O'Reilly, Kelley A.

    2010-01-01

    This work elaborates the impacts of strategically constructed silos that are not byproducts of flagging cross-departmental cooperation or the cumulative effect of decades of decentralized command and control. Rather, these silos are strategically intended structures within organizations. Most significantly, the substantive theory of strategically constructed silos and their impact on customer service contributes to the field by illustrating the presence and consequence of silos occurring in s...

  4. Self-reported household impacts of large-scale chemical contamination of the public water supply, Charleston, West Virginia, USA.

    Directory of Open Access Journals (Sweden)

    Charles P Schade

    Full Text Available A January 2014 industrial accident contaminated the public water supply of approximately 300,000 homes in and near Charleston, West Virginia (USA with low levels of a strongly-smelling substance consisting principally of 4-methylcyclohexane methanol (MCHM. The ensuing state of emergency closed schools and businesses. Hundreds of people sought medical care for symptoms they related to the incident. We surveyed 498 households by telephone to assess the episode's health and economic impact as well as public perception of risk communication by responsible officials. Thirty two percent of households (159/498 reported someone with illness believed to be related to the chemical spill, chiefly dermatological or gastrointestinal symptoms. Respondents experienced more frequent symptoms of psychological distress during and within 30 days of the emergency than 90 days later. Sixty-seven respondent households (13% had someone miss work because of the crisis, missing a median of 3 days of work. Of 443 households reporting extra expenses due to the crisis, 46% spent less than $100, while 10% spent over $500 (estimated average about $206. More than 80% (401/485 households learned of the spill the same day it occurred. More than 2/3 of households complied fully with "do not use" orders that were issued; only 8% reported drinking water against advice. Household assessments of official communications varied by source, with local officials receiving an average "B" rating, whereas some federal and water company communication received a "D" grade. More than 90% of households obtained safe water from distribution centers or stores during the emergency. We conclude that the spill had major economic impact with substantial numbers of individuals reporting incident-related illnesses and psychological distress. Authorities were successful supplying emergency drinking water, but less so with risk communication.

  5. Soil chemicals properties and wheat genotype impact on micronutrient and toxic elements content in wheat integral flour

    Directory of Open Access Journals (Sweden)

    Krunoslav Karalić

    2012-02-01

    Full Text Available Aim To determine impact of soil chemical properties and different wheat genotypes in Croatia on micronutrient and toxic elements content in wheat integral flour. Methods Research was conducted and soil samples were collected from two different production areas in the Republic of Croatia: Ovčara and Dalj. Besides soil samples, grain samples of four different Croatian wheat genotypes were also collected and analyzed. In total, 40 samples of soil and 40 samples of wheat grain were analysed for total (aqua regia and plant available (EDTA extraction heavy metal content of Fe, Mn, Zn, Cu, Pb, Cd. Results Determined soil pHKCl ranged from 5.63 to 6.25 at Ovčara and from 6.95 to 7.37 at Dalj sampling sites. The highest total concentration of heavy metals in soil were determined for Fe, followed by Mn, Zn, Cu, Pb and the lowest total concentration wasrecorded for Cd. The highest EDTA concentrations in soil were determined for Mn, than followed by Fe, Cu, Pb, and the lowest EDTA concentration was recorded for Cd. The highest concentration in integral wheat flour was found for Fe, than lower for Mn, Zn, Cu, Pb and the lowest concentration was found for Cd. If consumers in Croatia used daily 203 g of bread made of integral flour, they would take 2.31 to 8.44 µg Cd daily, depending on soil and wheat genotype.Conclusion The analysed soil and winter wheat genotypes have significant impact on potential daily intake of toxic and essentialheavy metals by integral flour or bread.

  6. Effective impact ionization threshold and piecewise linear approximation for impact ionization coefficients in a theory of superfast ionizing fronts in semiconductors

    Science.gov (United States)

    Minarsky, Andrey; Rodin, Pavel

    2013-04-01

    We focus on theoretical description of superfast ionizing fronts in semiconductor p+-n-n+ structures and argue that in the context of this problem, Townsend's type field dependence of impact ionization coefficients α(E)=α0 exp[(-E0/E)m] can be well approximated by a threshold piecewise linear dependence α(E)=α0'(E -Eb)Θ(E -Eb), where Θ(x) is the unit step function. The possibility of such approximation explains the threshold square dependence υf˜(Em-Eb)2 of the front velocity υf on the maximum electric field Em that the theory of TRAPATT-like ionizing fronts predicts even for threshold-free Townsend's approximation. We suggest a procedure for finding the best-fit parameters of the piecewise linear dependence and determine the values Eb≈0.21 E0, α0'≈0.46α0/E0 for the power m =1 and Eb≈0.5 E0, α0'≈0.7α0/E0 for the power m =2.

  7. In Situ Field-Based Metabolomics for Evaluating the Impacts of Exposure to Chemicals of Emerging Concern Relative to Other Stressors

    Science.gov (United States)

    Significant attention is being devoted to the potential impacts on ecosystems from exposure to chemicals of emerging concern (CECs; including pharmaceuticals, personal-care products, etc.). Many of these are persistent, distributed globally, and have been shown to cause adverse i...

  8. Geochemistry of the Dissolved Load of the Changjiang Basin Rivers: Anthropogenic Impacts and Chemical Weathering, Evidences from Major Elements, Sr and B Isotopes

    Institute of Scientific and Technical Information of China (English)

    Benjamin Chetelat; LIU Cong-qiang

    2008-01-01

    @@ 1 Introduction Rivers provide a unique opportunity to have average information about chemical and physical erosion, about the major geochemical fractionations created by these major geological processes but also about the impact and disturbances of human activities on the Earth Engine.

  9. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice: Part II: Impact on specific chemical and biochemical quality parameters

    NARCIS (Netherlands)

    Vervoort, L.; Plancken, van der I.; Grauwet, T.; Timmermans, R.A.H.; Mastwijk, H.C.; Matser, A.M.; Hendrickx, M.E.; Loey, van A.

    2011-01-01

    The impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurization of orange juice was compared on a fair basis, using processing conditions leading to an equivalent degree of microbial inactivation. Examining the effect on specific chemical and biochemical

  10. The Impact of Technology and Distance Education: A Classical Learning Theory Viewpoint

    Directory of Open Access Journals (Sweden)

    Herb Thompson

    1999-01-01

    Full Text Available For the past two years the author has been teaching economics (History of Economic Thought and Economic Development at the tertiary level via the Internet and computer-mediation. This is done primarily for students who are unable or who do not wish to attend classes on campus, but desire an education as good, if not better, as the campus based enterprise. This paper provides a reflective analysis of the theoretical content of that practice. Teaching ‘online’ is a vastly different enterprise than face-to-face exercises, thereby demanding a revaluation of one’s pedagogical theory and praxis. In The German Ideology, Marx and Engels articulated their claim that historically dominant classes embody their ideas in essential forms, representing them as universally valid. It is within this framework that we begin to examine what it means to "know" in economics. How knowledge is legitimated in universities continues to be under-theorised, particularly with regard to electronic transmission. The mechanism of transmission of particular concern here is that which is computer-mediated. Landow represents hypertext as the latest flowering in a long march of democratic processes originating in the displacement of Platonic authority by the lesser authority of the written word. It is argued here that the determinism of the "progressive narrative" within and around the "hypertext revolution" deserves careful scrutiny, particularly in its application to pedagogy. Pedagogical artefacts, such as computers, mediate the transmission of ideas. The question "how does this happen?" relates to the complexity of theorizing the relationship between the educational process and the social relations of capitalist social formations. Over two decades ago, Bowles and Gintis attempted a Marxist understanding of the nature of this relationship. In their conception, pedagogical mechanisms were seen to operate in a fairly deterministic way to mirror and model the norms and values

  11. 云理论的规制影响评估%A regulation impact assessment method based on cloud theory

    Institute of Scientific and Technical Information of China (English)

    尚士雄; 西宝

    2011-01-01

    As an effective tool used to evaluate and improve regulation policy, regulatory impact analysis has transferred gradually from developed countries to developing countries. With the lack of regulatory operating framework, inadequate institutions and skills, and a lack of transparency, the application of regulation impact assessment ( RIA ) made slow progress in developing countries, and required an appropriate method to assess the realities of the regulation performance. At first, the coincidence of cloud theory methods and RIA were analyzed, and on this basis, regulatory impact assessment models were built and application examples were taken. The model analyzed the regulatory impact under the social-physical network frame, which may solve the data collection problem in traditional cost-benefit analysis and evaluate the composite effectiveness of regulatory systems, unceasingly improve and increase the quality and efficiency of government regulation.%作为衡量和改进规制政策有效性的工具,规制影响分析逐渐由发达国家向发展中国家渗透和转移.由于发展中国家规制运行框架缺乏,机构和技能不足以及缺乏透明度等导致规制影响评估在发展中国家的应用进展缓慢,因此需要结合实际寻找并使用对规制绩效进行评估的合适方法.首先分析了云理论方法与规制影响评估之间的契合性,在此基础上构建了规制影响评估模型并进行了应用举例.该模型可以解决传统成本收益分析的数据收集问题并对规制系统的有效性进行综合评价,避免了以往因某些非理性因素而产生的主观臆断和盲目决策情况发生,使政府规制的质量和效率得以不断改善和提高.

  12. The Nature of the Chemical Process. 1. Symmetry Evolution – Revised Information Theory, Similarity Principle and Ugly Symmetry

    Directory of Open Access Journals (Sweden)

    Shu-Kun Lin

    2001-03-01

    Full Text Available Abstract: Symmetry is a measure of indistinguishability. Similarity is a continuous measure of imperfect symmetry. Lewis' remark that “gain of entropy means loss of information” defines the relationship of entropy and information. Three laws of information theory have been proposed. Labeling by introducing nonsymmetry and formatting by introducing symmetry are defined. The function L ( L=lnw, w is the number of microstates, or the sum of entropy and information, L=S+I of the universe is a constant (the first law of information theory. The entropy S of the universe tends toward a maximum (the second law law of information theory. For a perfect symmetric static structure, the information is zero and the static entropy is the maximum (the third law law of information theory. Based on the Gibbs inequality and the second law of the revised information theory we have proved the similarity principle (a continuous higher similarity−higher entropy relation after the rejection of the Gibbs paradox and proved the Curie-Rosen symmetry principle (a higher symmetry−higher stability relation as a special case of the similarity principle. The principles of information minimization and potential energy minimization are compared. Entropy is the degree of symmetry and information is the degree of nonsymmetry. There are two kinds of symmetries: dynamic and static symmetries. Any kind of symmetry will define an entropy and, corresponding to the dynamic and static symmetries, there are static entropy and dynamic entropy. Entropy in thermodynamics is a special kind of dynamic entropy. Any spontaneous process will evolve towards the highest possible symmetry, either dynamic or static or both. Therefore the revised information theory can be applied to characterizing all kinds of structural stability and process spontaneity. Some examples in chemical physics have been given. Spontaneous processes of all kinds of molecular

  13. Cognitive Load and Self-Determination Theories Applied to E-Learning: Impact on Students' Participation and Academic Performance.

    Directory of Open Access Journals (Sweden)

    Tiago de Araujo Guerra Grangeia

    Full Text Available Emergency clerkships expose students to a stressful environment that require multiple tasks, which may have a direct impact on cognitive load and motivation for learning. To address this challenge, Cognitive Load Theory and Self Determination Theory provided the conceptual frameworks to the development of a Moodle-based online Emergency Medicine course, inspired by real clinical cases.Three consecutive classes (2013-2015 of sixth-year medical students (n = 304 participated in the course, during a curricular and essentially practical emergency rotation. "Virtual Rounds" provided weekly virtual patients in narrative format and meaningful schemata to chief complaints, in order to simulate real rounds at Emergency Unit. Additional activities such as Extreme Decisions, Emergency Quiz and Electrocardiographic challenge offered different views of emergency care. Authors assessed student´s participation and its correlation with their academic performance. A survey evaluated students´ opinions. Students graduating in 2015 answered an online questionnaire to investigate cognitive load and motivation.Each student produced 1965 pageviews and spent 72 hours logged on. Although Clinical Emergency rotation has two months long, students accessed the online course during an average of 5.3 months. Virtual Rounds was the most accessed activity, and there was positive correlations between the number of hours logged on the platform and final grades on Emergency Medicine. Over 90% of students felt an improvement in their clinical reasoning and considered themselves better prepared for rendering Emergency care. Considering a Likert scale from 1 (minimum load to 7 (maximum load, the scores for total cognitive load were 4.79±2.2 for Virtual Rounds and 5.56±1.96 for real medical rounds(p<0,01.A real-world inspired online course, based on cognitive and motivational conceptual frameworks, seems to be a strong tool to engage students in learning. It may support them to

  14. Spin and spatial dynamics in electron-impact scattering off S-wave He using R-matrix with Time-Dependence theory

    CERN Document Server

    Wragg, Jack

    2016-01-01

    R-matrix with time-dependence theory is applied to electron-impact ionisation processes for He in the S-wave model. Cross sections for electron-impact excitation, ionisation and ionisation with excitation for impact energies between 25 and 225 eV are in excellent agreement with benchmark cross sections. Ultra-fast dynamics induced by a scattering event is observed through time-dependent signatures associated with autoionisation from doubly excited states. Further insight into dynamics can be obtained through examination of the spin components of the time-dependent wavefunction.

  15. On the Theory of Oxidation-Reduction Reactions Involving Electron Transfer. V. Comparison and Properties of Electrochemical and Chemical Rate Constants

    Science.gov (United States)

    Marcus, R. A.

    1962-01-01

    Using a theory of electron transfers which takes cognizance of reorganization of the medium outside the inner coordination shell and of changes of bond lengths inside it, relations between electrochemical and related chemical rate constants are deduced and compared with the experimental data. A correlation is found, without the use of arbitrary parameters. Effects of weak complexes with added electrolytes are included under specified conditions. The deductions offer a way of coordinating a variety of data in the two fields, internally as well as with each those in another. For example, the rate of oxidation or reduction of a series of related reactants by one reagent is correlated with that of another and with that of the corresponding electrochemical oxidation-reduction reaction, under certain specified conditions. These correlations may also provide a test for distinguishing an electron from an atom transfer mechanism. (auth)

  16. Rigorous ab initio quantum embedding for quantum chemistry using Green's function theory: screened interaction, non-local self-energy relaxation, orbital basis, and chemical accuracy

    CERN Document Server

    Lan, Tran Nguyen; Zgid, Dominika

    2016-01-01

    We present a detailed discussion of self-energy embedding theory (SEET) which is a quantum embedding scheme allowing us to describe a chosen subsystem very accurately while keeping the description of the environment at a lower cost. We apply SEET to molecular examples where commonly our chosen subsystem is made out of a set of strongly correlated orbitals while the weakly correlated orbitals constitute an environment. Such a self-energy separation is very general and to make this procedure applicable to multiple systems a detailed and practical procedure for the evaluation of the system and environment self-energy is necessary. We list all the intricacies for one of the possible procedures while focusing our discussion on many practical implementation aspects such as the choice of best orbital basis, impurity solver, and many steps necessary to reach chemical accuracy. Finally, on a set of carefully chosen molecular examples, we demonstrate that SEET which is a controlled, systematically improvable Green's fu...

  17. Impact Study of PMSG-Based Wind Power Penetration on Power System Transient Stability Using EEAC Theory

    Directory of Open Access Journals (Sweden)

    Zhongyi Liu

    2015-11-01

    Full Text Available Wind turbines with direct-driven permanent magnet synchronous generators (PMSGs are widely used in wind power generation. According to the dynamic characteristics of PMSGs, an impact analysis of PMSG-based wind power penetration on the transient stability of multi-machine power systems is carried out in this paper based on the theory of extended equal area criterion (EEAC. Considering the most severe PMSG integration situation, the changes in the system’s equivalent power-angle relationships after integrating PMSGs are studied in detail. The system’s equivalent mechanical input power and the fault period electrical output power curves are found to be mainly affected. The analysis demonstrates that the integration of PMSGs can cause either detrimental or beneficial effects on the system transient stability. It is determined by several factors, including the selection of the synchronous generators used to balance wind power, the reactive power control mode of PMSGs and the wind power penetration level. Two different simulation systems are also adopted to verify the analysis results.

  18. On the usage of classical nucleation theory in quantification of the impact of bacterial INP on weather and climate

    Science.gov (United States)

    Sahyoun, Maher; Wex, Heike; Gosewinkel, Ulrich; Šantl-Temkiv, Tina; Nielsen, Niels W.; Finster, Kai; Sørensen, Jens H.; Stratmann, Frank; Korsholm, Ulrik S.

    2016-08-01

    Bacterial ice-nucleating particles (INP) are present in the atmosphere and efficient in heterogeneous ice-nucleation at temperatures up to -2 °C in mixed-phase clouds. However, due to their low emission rates, their climatic impact was considered insignificant in previous modeling studies. In view of uncertainties about the actual atmospheric emission rates and concentrations of bacterial INP, it is important to re-investigate the threshold fraction of cloud droplets containing bacterial INP for a pronounced effect on ice-nucleation, by using a suitable parameterization that describes the ice-nucleation process by bacterial INP properly. Therefore, we compared two heterogeneous ice-nucleation rate parameterizations, denoted CH08 and HOO10 herein, both of which are based on classical-nucleation-theory and measurements, and use similar equations, but different parameters, to an empirical parameterization, denoted HAR13 herein, which considers implicitly the number of bacterial INP. All parameterizations were used to calculate the ice-nucleation probability offline. HAR13 and HOO10 were implemented and tested in a one-dimensional version of a weather-forecast-model in two meteorological cases. Ice-nucleation-probabilities based on HAR13 and CH08 were similar, in spite of their different derivation, and were higher than those based on HOO10. This study shows the importance of the method of parameterization and of the input variable, number of bacterial INP, for accurately assessing their role in meteorological and climatic processes.

  19. Assessing the ecological long-term impact of wastewater irrigation on soil and water based on bioassays and chemical analyses.

    Science.gov (United States)

    Richter, Elisabeth; Hecht, Fabian; Schnellbacher, Nadine; Ternes, Thomas A; Wick, Arne; Wode, Florian; Coors, Anja

    2015-11-01

    The reuse of treated wastewater for irrigation and groundwater recharge can counteract water scarcity and reduce pollution of surface waters, but assessing its environmental risk should likewise consider effects associated to the soil. The present study therefore aimed at determining the impact of wastewater irrigation on the habitat quality of water after soil passage and of soil after percolation by applying bioassays and chemical analysis. Lab-scale columns of four different soils encompassing standard European soil and three field soils of varying characteristics and pre-contamination were continuously percolated with treated wastewater to simulate long-term irrigation. Wastewater and its percolates were tested for immobilization of Daphnia magna and growth inhibition of green algae (Pseudokirchneriella subcapitata) and water lentils (Lemna minor). The observed phytotoxicity of the treated wastewater was mostly reduced by soil passage, but in some percolates also increased for green algae. Chemical analysis covering an extensive set of wastewater-born organic pollutants demonstrated that many of them were considerably reduced by soil passage, particularly through peaty soils. Taken together, these results indicated that wastewater-born phytotoxic substances may be removed by soil passage, while existing soil pollutants (e.g. metals) may leach and impair percolate quality. Soils with and without wastewater irrigation were tested for growth of plants (Avena sativa, Brassica napus) and soil bacteria (Arthrobacter globiformis) and reproduction of collembolans (Folsomia candida) and oligochaetes (Enchytraeus crypticus, Eisenia fetida). The habitat quality of the standard and two field soils appeared to be deteriorated by wastewater percolation for at least one organism (enchytraeids, plants or bacteria), while for two pre-contaminated field soils it also was improved (for plants and/or enchytraeids). Wastewater percolation did not seem to raise soil concentrations

  20. Impact

    NARCIS (Netherlands)

    Lohse, Detlef; Bergmann, Raymond; Mikkelsen, Rene; Zeilstra, Christiaan; Meer, van der Devaraj; Versluis, Michel

    2004-01-01

    A lot of information on impacts of solid bodies on planets has been extracted from remote observations of impact craters on planetary surfaces; experiments however with large enough impact energies as compared to the energy stored in the ground are difficult. We approach this problem by downscaled e

  1. Exploring the Impact of Commuter’s Residential Location Choice on the Design of a Rail Transit Line Based on Prospect Theory

    Directory of Open Access Journals (Sweden)

    Ding Liu

    2014-01-01

    Full Text Available This paper explores the impact of prospect theory based commuter’s residential location choice on the design problem of a rail transit line located in a monocentric city. A closed-form social welfare maximization model is proposed, with special consideration given to prospect theory based commuter’s residential location choice over years. Commuters are assumed to make residential location choice by a trade-off between daily housing rent and generalized travel cost to minimize their prospect values. The solutions properties of the proposed model are explored and compared analytically. It is found that overestimation exists for the optimal solutions of rail line length, headway, and fare based on traditional utility theory, compared with the optimal solutions of the proposed prospect theory based model. A numerical example is given to illustrate the properties of the proposed model.

  2. A theory for the origin of a self-replicating chemical system. I - Natural selection of the autogen from short, random oligomers

    Science.gov (United States)

    White, D. H.

    1980-01-01

    A general theory is presented for the origin of a self-replicating chemical system, termed an autogen, which is capable of both crude replication and translation (protein synthesis). The theory requires the availability of free energy and monomers to the system, a significant background low-yield synthesis of kinetically stable oligopeptides and oligonucleotides, the localization of the oligomers, crude oligonucleotide selectivity of amino acids during oligopeptide synthesis, crude oligonucleotide replication, and two short peptide families which catalyze replication and translation, to produce a localized group of at least one copy each of two protogenes and two protoenzymes. The model posits a process of random oligomerization, followed by the random nucleation of functional components and the rapid autocatalytic growth of the functioning autogen to macroscopic amounts, to account for the origin of the first self-replicating system. Such a process contains steps of such high probability and short time periods that it is suggested that the emergence of an autogen in a laboratory experiment of reasonable time scale may be possible.

  3. Impact of temperature and storage duration on the chemical and odor quality of military packaged water in polyethylene terephthalate bottles

    Energy Technology Data Exchange (ETDEWEB)

    Greifenstein, Michael, E-mail: Michael.Greifenstein@us.army.mil [Department of Preventive Medicine and Biometrics, 4301 Jones Bridge Road, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 (United States); White, Duvel W., E-mail: duvel.white@us.army.mil [Department of Preventive Medicine and Biometrics, 4301 Jones Bridge Road, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 (United States); Stubner, Alex, E-mail: alex.stubner@usuhs.edu [Department of Preventive Medicine and Biometrics, 4301 Jones Bridge Road, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 (United States); Hout, Joseph, E-mail: joseph.hout@usuhs.edu [Department of Preventive Medicine and Biometrics, 4301 Jones Bridge Road, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 (United States); Whelton, Andrew J., E-mail: ajwhelton@southalabama.edu [Department of Civil Engineering, 3021 Shelby Hall, University of South Alabama, Mobile, AL 36688 (United States)

    2013-07-01

    The impact of temperature and storage time on military packaged water (MPW) quality was examined at four temperatures (23.0 °C to 60.0 °C) for 120 days. Polyethylene terephthalate (PET) bottles were filled in California and Afghanistan with unbuffered water treated by reverse osmosis. The US military's water pH long-term potability standard was exceeded, and US Food and Drug Administration (USFDA) and US Environmental Protection Agency (USEPA) drinking water pH and odor intensity limits were also exceeded. During a 70 day exposure period, Port Hueneme MPW total organic carbon and total trihalomethane levels increased from < 0.25 mg/L to 2.0 ± 0.0 mg/L and < 0.05 μg/L to 51.5 ± 2.1 μg/L, respectively. PET released organic contaminants into MPW and residual disinfectant generated trihalomethane contaminants. After 14 days at 37.7 °C and 60.0 °C, Afghanistan MPW threshold odor number values were 8.0 and 8.6, respectively. Total organic carbon concentration only increased with exposure duration at 60.0 °C. Acetaldehyde and formaldehyde contaminants were not detected likely due to the high method detection limits applied in this study. Phthalate contaminants detected and their maximum levels were butylbenzylphthalate (BBP) 0.43 μg/L, di-n-butylphthalate (DnBP) 0.38 μg/L, di(2-ethylhexyl)phthalate (DEHP) 0.6 μg/L, and diethylphthalate (DEP) 0.32 μg/L. Antimony was only detected in 60.0 °C Afghanistan MPW on Day 28 and beyond, and its maximum concentration was 3.6 ± 0.3 μg/L. No antimony was found in bottles exposed to lesser temperatures. Environmental health, PET synthesis and bottle manufacturers, and bottle users can integrate results of this work to improve health protective decisions and doctrine. - Highlights: • Temperature and storage time impacted military bottled water quality up to 60 °C. • The chemical quality of water bottled in California and Afghanistan was affected. • Drinking water pH and odor intensity limits were also

  4. Are extracted materials truly representative of original samples? Impact of C18 extraction on CDOM optical and chemical properties

    Directory of Open Access Journals (Sweden)

    Andrea A Andrew

    2016-02-01

    Full Text Available Some properties of dissolved organic matter (DOM and chromophoric dissolved organic matter (CDOM can be easily measured directly on whole waters, while others require sample concentration and removal of natural salts. To increase CDOM content and eliminate salts, solid phase extraction is often employed. Biases following extraction and elution are inevitable, thus raising the question of how truly representative the extracted material is of the original. In this context, we investigated the wavelength dependence of extraction efficiency for C18 cartridges with respect to CDOM optical properties using samples obtained from the Middle Atlantic Bight (MAB and the Equatorial Atlantic Ocean (EAO. Further, we compared the optical changes of C18 extracts and the corresponding whole water following chemical reduction with sodium borohydride (NaBH4.C18 cartridges preferentially extracted long-wavelength absorbing/emitting material for samples impacted by riverine input. Extraction efficiency overall decreased with offshore distance away from riverine input. Spectral slopes of C18-OM samples were also almost always lower than those of their corresponding CDOM samples supporting the preferential extraction of higher molecular weight absorbing material. The wavelength dependence of the optical properties (absorption, fluorescence emission and quantum yield of the original water samples and their corresponding extracted material were very similar. C18 extracts and corresponding water samples further exhibited comparable optical changes following NaBH4 reduction, thus suggesting a similarity in nature (structure of the optically active extracted material, independent of geographical locale. Altogether, these data suggested a strong similarity between C18 extracts and corresponding whole waters, thus indicating that extracts are representative of the CDOM content of original waters.

  5. Impact of herbicides on some agronomic and chemical characteristics of flue-cured virginia (FCV tobacco (Nicotiana tabacum L.

    Directory of Open Access Journals (Sweden)

    Muhammad Azim Khan

    2006-09-01

    Full Text Available A field experiment was carried out at Tobacco Research Station Khan Ghari, Mardan, (NWFP- Pakistan during spring 2003 to study the impact of herbicides on some agronomic and chemical characteristics of flue-cured virginia (FCV tobacco (Nicotiana tabacum L.. The experiment was laid out in RCB design, replicated four times with ten treatments, comprising hand weeding, weedy check, pre-transplanting herbicides; S-metalocholar @ 1.92, pendimethalin (EC @ 1.00, pendimethalin (CS @ 1.00, and butralin @ 1.44 kg a.i ha-1 and the post-transplanting herbicides include; clodinafop @ 0.04, fenoxaprop-p-ethyl @ 1.00, acetochlor @ 0.125 and glyphosate @ 0.95 kg a.i ha-1. None of the herbicides except S-metalocholar had a phytotoxic effect on tobacco. All the parameters except the number of leaves plant-1 were significantly affected by different treatments. The highest (228.3 weeds density m-2 was observed in weedy check while minimum (69 was recorded in pendimethalin (EC treatment. The maximum grade index of 74.60% was recorded in acetochlor and minimum grade index of 53.88% was recorded in S-metalocholar treatments. Nicotine (% was higher in pendimethalin (EC treated plots with 2.362%; however it was comparable to all other treatments. The maximum percent reducing sugar of 18.22% was recorded in pendimethalin (CS treatment, while minimum of 12.42% reducing sugar was recorded in weedy check. Similarly maximum yield of 2465 kg ha-1 was recorded in pendimethalin (EC treatment and minimum yield of 1703 kg ha-1 was recorded in weedy check (control treatment. Thus it can be concluded from the experiment that herbicides proved effective against weeds and their growth and promoted tobacco quality and yield. Hence the use of herbicides not only increases the net income of the farmers but also will make the weed seed bank poorer.

  6. New density functional theory approaches for enabling prediction of chemical and physical properties of plutonium and other actinides.

    Energy Technology Data Exchange (ETDEWEB)

    Mattsson, Ann Elisabet

    2012-01-01

    Density Functional Theory (DFT) based Equation of State (EOS) construction is a prominent part of Sandia's capabilities to support engineering sciences. This capability is based on amending experimental data with information gained from computational investigations, in parts of the phase space where experimental data is hard, dangerous, or expensive to obtain. A prominent materials area where such computational investigations are hard to perform today because of limited accuracy is actinide and lanthanide materials. The Science of Extreme Environment Lab Directed Research and Development project described in this Report has had the aim to cure this accuracy problem. We have focused on the two major factors which would allow for accurate computational investigations of actinide and lanthanide materials: (1) The fully relativistic treatment needed for materials containing heavy atoms, and (2) the needed improved performance of DFT exchange-correlation functionals. We have implemented a fully relativistic treatment based on the Dirac Equation into the LANL code RSPt and we have shown that such a treatment is imperative when calculating properties of materials containing actinides and/or lanthanides. The present standard treatment that only includes some of the relativistic terms is not accurate enough and can even give misleading results. Compared to calculations previously considered state of the art, the Dirac treatment gives a substantial change in equilibrium volume predictions for materials with large spin-orbit coupling. For actinide and lanthanide materials, a Dirac treatment is thus a fundamental requirement in any computational investigation, including those for DFT-based EOS construction. For a full capability, a DFT functional capable of describing strongly correlated systems such as actinide materials need to be developed. Using the previously successful subsystem functional scheme developed by Mattsson et.al., we have created such a functional. In

  7. [HEALTH STATUS OF ELECTROTECHNICAL PERSONNEL EXPOSED TO THE COMBINED IMPACT OF ELECTROMAGNETIC FIELDS OF 50 HZ AND CHEMICALS].

    Science.gov (United States)

    Rusin, M N; Amirov, N Kh; Sibgatullin, A S; Krasnoshchekova, V N

    2015-01-01

    There was performed an analysis of the working conditions and health status of workers of the chemical enterprise. In male electrical staff exposed to electromagnetic fields (EMF) of 50 Hz and chemicals, according to data of periodic medical examinations there was revealed statistically higher incidence of cardiovascular diseases and autonomic disorders. The obtained preliminary results allow to suggest the upsurge of the involvement of the autonomic nervous system in response to the combined effects of EMF of 50 Hz and chemicals.

  8. The Impact of Microbial Ecology and Chemical Profile on the Enhanced Biological Phosphorus Removal (EBPR) Process: A Case Study of Northern Wastewater Treatment Works, Johannesburg

    OpenAIRE

    Ilunga Kamika; Martie Coetzee; Bhekie Brilliance Mamba; Titus Msagati; Momba, Maggy N.B.

    2014-01-01

    The impact of polyphosphate-accumulating organism (PAO) and glycogen-accumulating organism (GAO) populations as well as of the chemical profile on the performance of Unit-3 (open elutriation tanks) and Unit-5 (covered elutriation tank) of the City of Johannesburg Northern Wastewater Treatment Works was determined. Physicochemical parameters of wastewater samples were measured using standard methods. Bacterial diversity was determined using 16S rRNA gene amplicon pyrosequencing of the variabl...

  9. Application of supersonic linear theory and hypersonic impact methods to three nonslender hypersonic airplane concepts at Mach numbers from 1.10 to 2.86

    Science.gov (United States)

    Pittman, J. L.

    1979-01-01

    Aerodynamic predictions from supersonic linear theory and hypersonic impact theory were compared with experimental data for three hypersonic research airplane concepts over a Mach number range from 1.10 to 2.86. The linear theory gave good lift prediction and fair to good pitching-moment prediction over the Mach number (M) range. The tangent-cone theory predictions were good for lift and fair to good for pitching moment for M more than or equal to 2.0. The combined tangent-cone theory predictions were good for lift and fair to good for pitching moment for M more than or equal to 2.0. The combined tangent-cone/tangent-wedge method gave the least accurate prediction of lift and pitching moment. The zero-lift drag was overestimated, especially for M less than 2.0. The linear theory drag prediction was generally poor, with areas of good agreement only for M less than or equal to 1.2. For M more than or equal to 2.), the tangent-cone method predicted the zero-lift drag most accurately.

  10. Impact of environmental chemicals, sociodemographic variables, depression, and clinical indicators of health and nutrition on self-reported health status

    Science.gov (United States)

    Public health researchers ideally integrate social, environmental, and clinical measures to identify predictors of poor health. Chemicals measured in human tissues are often evaluated in relation to intangible or rare health outcomes, or are studied one chemical at a time. Using ...

  11. Modelling the impact of the environmental scenario on population recovery from chemical stress exposure: a case study using Daphnia magna.

    Science.gov (United States)

    Gabsi, Faten; Preuss, Thomas G

    2014-11-01

    Recovery of organisms is an important attribute for evaluating the acceptability of chemicals' effects in ecological risk assessment in Europe. Recovery in the field does not depend on the chemical's properties and type of exposure only, but it is strongly linked to important environmental variables and biological interactions as well. Yet, these remain only marginally considered in the European risk assessment of chemicals. Here, we use individual-based modelling to investigate how the environmental scenario affects Daphnia magna population recovery from chemical exposure. Simulation experiments were performed for chemicals with lethality levels ranging from 40% to 90% at different food and temperature conditions. The same toxicity levels were then tested in combination with biological interactions including predation or competition. Results show that for the same chemical effect strength, populations often exhibited different recovery times in a different environmental context. The interactions between the chemical and the environmental variables were the strongest determinants of population recovery. Most important, biotic interactions even induced opposite effects on recovery at low and at high mortality levels. Results of this study infer that no specific role can be attributed to any abiotic or biotic variable in isolation. We conclude that unless the complex interactive mechanisms between the different factors constituting the full environmental scenario are taken into account in risk assessment, we cannot achieve a complete understanding of recovery processes from chemical effects. PMID:25261821

  12. Impact of vetch cover crop on runoff, soil loss, soil chemical properties and yield of chickpea in North Gondar, Ethiopia

    Science.gov (United States)

    Demelash, Nigus; Klik, Andreas; Holzmann, Hubert; Ziadat, Feras; Strohmeier, Stefan; Bayu, Wondimu; Zucca, Claudio; Abera, Atikilt

    2016-04-01

    Cover crops improve the sustainability and quality of both natural system and agro ecosystem. In Gumara-Maksegnit watershed which is located in Lake Tana basin, farmers usually use fallow during the rainy season for the preceding chickpea production system. The fallowing period can lead to soil erosion and nutrient losses. A field experiment was conducted during growing seasons 2014 and 2015 to evaluate the effect of cover crops on runoff, soil loss, soil chemical properties and yield of chickpea in North Gondar, Ethiopia. The plot experiment contained four treatments arranged in Randomized Complete Block Design with three replications: 1) Control plot (Farmers' practice: fallowing- without cover crop), 2) Chickpea planted with Di-ammonium phosphate (DAP) fertilizer with 46 k ha-1 P2O5 and 23 k ha-1 nitrogen after harvesting vetch cover crop, 3) Chick pea planted with vetch cover crop incorporated with the soil as green manure without fertilizer, 4) Chick pea planted with vetch cover crop and incorporated with the soil as green manure and with 23 k ha-1 P2O5 and 12.5 k ha-1 nitrogen. Each plot with an area of 36 m² was equipped with a runoff monitoring system. Vetch (Vicia sativa L.) was planted as cover crop at the onset of the rain in June and used as green manure. The results of the experiment showed statistically significant (P 0.05) on average plant height, average number of branches and hundred seed weight. Similarly, the results indicated that cover crop has a clear impact on runoff volume and sediment loss. Plots with vetch cover crop reduce the average runoff by 65% and the average soil loss decreased from 15.7 in the bare land plot to 8.6 t ha-1 with plots covered by vetch. In general, this result reveales that the cover crops, especially vetch, can be used to improve chickpea grain yield in addition to reduce soil erosion in the watershed.

  13. Impact of Education Based on Theory of Planned Behavior: An Investigation into Hypertension-Preventive Self-care Behaviors in Iranian Girl Adolescent

    OpenAIRE

    Shabnam POOREH; Zahra HOSSEINI-NODEH

    2015-01-01

    Background: Since risk factors of hypertension are formed during adolescent period and regarding that attitudes change occurs more easily in these ages, the present paper aimed to evaluate the impact of education based on the theory of planned behavior in hypertension prevention behaviors in female adolescent students.Methods: In this quasi-experimental study, 160 girls of 12-16 yr old (80 in each case and control group), who had not been educated in prevention of hypertension over the recent...

  14. SAFT缔合模型关联含水体系的1H NMR%Correlation of 1H NMR Chemical Shift for Aqueous Solutions by Statistical Associating Fluid Theory Association Model

    Institute of Scientific and Technical Information of China (English)

    许波; 李浩然; 王从敏; 许映杰; 韩世钧

    2005-01-01

    1H NMR chemical shifts of binary aqueous mixtures of acylamide, alcohol, dimethyl sulphoxide (DMSO), and acetone are correlated by statistical associating fluid theory (SAFT) association model. The comparison between SAFT association model and Wilson equation shows that the former is better for dealing with aqueous solutions. Finally, the specialties of both models are discussed.

  15. Entrepreneurial Orientation of Community College Workforce Divisions and the Impact of Organizational Structure: A Grounded Theory Study

    Science.gov (United States)

    Schiefen, Kathleen M.

    2010-01-01

    This research focused on how organizational structure of community colleges influenced the entrepreneurial orientation of deans, directors, vice presidents, and vice chancellors of workforce units. Using grounded theory methodology, the researcher identified three emergent theories applicable to both integrated and separate workforce units. These…

  16. Human toxicology of chemical mixtures toxic consequences beyond the impact of one-component product and environmental exposures

    CERN Document Server

    Zeliger, Harold I

    2011-01-01

    In this important reference work, Zeliger catalogs the known effects of chemical mixtures on the human body and also proposes a framework for understanding and predicting their actions in terms of lipophile (fat soluble)/hydrophile (water soluble) interactions. The author's focus is on illnesses that ensue following exposures to mixtures of chemicals that cannot be attributed to any one component of the mixture. In the first part the mechanisms of chemical absorption at a molecular and macromolecular level are explained, as well as the body's methods of defending itself against xenobiotic intrusion. Part II examines the sources of the chemicals discussed, looking at air and water pollution, food additives, pharmaceuticals, etc. Part III, which includes numerous case studies, examines specific effects of particular mixtures on particular body systems and organs and presents a theoretical framework for predicting what the effects of uncharacterized mixtures might be. Part IV covers regulatory requirements and t...

  17. Testing and Risk Assessment of Chemicals that Impact Highly Adaptive Biological Systems: The Case of Endocrine Systems

    Science.gov (United States)

    Animals have evolved a variety of mechanisms for responding to toxic chemicals of both natural and anthropogenic origin. Well-known examples include activation of cellular repair pathways and induction of metabolizing enzymes. From a governmental regulatory perspective, these a...

  18. Donor–Acceptor Copolymers of Relevance for Organic Photovoltaics: A Theoretical Investigation of the Impact of Chemical Structure Modifications on the Electronic and Optical Properties

    KAUST Repository

    Pandey, Laxman

    2012-08-28

    We systematically investigate at the density functional theory level how changes to the chemical structure of donor-acceptor copolymers used in a number of organic electronics applications influences the intrinsic geometric, electronic, and optical properties. We consider the combination of two distinct donors, where a central five-membered ring is fused on both sides by either a thiophene or a benzene ring, with 12 different acceptors linked to the donor either directly or through thienyl linkages. The interplay between the electron richness/deficiency of the subunits as well as the evolution of the frontier electronic levels of the isolated donors/acceptors plays a significant role in determining the electronic and optical properties of the copolymers. © 2012 American Chemical Society.

  19. Environmentally-Induced Malignancies: An In Vivo Model to Evaluate the Health Impact of Chemicals in Mixed Waste

    Energy Technology Data Exchange (ETDEWEB)

    Maria Pallavicini

    2001-05-04

    Occupational and environmental exposure to organic ligands, solvents, fuel hydrocarbons, and polychlorinated biphenyls are linked with increased risk of hematologic malignancies. DOE facilities and waste sites in the U.S. are contaminated with mixtures of potentially hazardous chemicals such as metals, organic ligands, solvents, fuel hydrocarbons, polychlorinated biphenyls and radioactive isotopes. A major goal of this project was to establish linkage between chemical/radiation exposure and induction of genomic damage in target populations with the capability to undergo transformation.

  20. Environmentally-Induced Malignancies: An In Vivo Model to Evaluate the Health Impact of Chemicals in Mixed Waste

    International Nuclear Information System (INIS)

    Occupational and environmental exposure to organic ligands, solvents, fuel hydrocarbons, and polychlorinated biphenyls are linked with increased risk of hematologic malignancies. DOE facilities and waste sites in the U.S. are contaminated with mixtures of potentially hazardous chemicals such as metals, organic ligands, solvents, fuel hydrocarbons, polychlorinated biphenyls and radioactive isotopes. A major goal of this project was to establish linkage between chemical/radiation exposure and induction of genomic damage in target populations with the capability to undergo transformation

  1. Impact of mechanical mowing and chemical treatment on phytosociological, pedochemical and biological parameters in roadside soils and vegetation.

    Science.gov (United States)

    Pellegrini, Elisa; Falcone, Lino; Loppi, Stefano; Lorenzini, Giacomo; Nali, Cristina

    2016-03-01

    Many chemical and non-chemical strategies have been applied to control weeds in agricultural and industrial areas. Knowledge regarding the effects of these methods on roadside vegetation is still poor. A 2-year field experiment was performed along a road located near Livorno (Tuscany, central Italy). Eight plots/strips were identified, of which four were subjected to periodical mechanical mowing and the remaining four were treated with a chemical herbicide based on glyphosate (the producer's recommended rates were used for the selective control of broad-leaved weeds). Our results clearly showed that roadside soil and vegetation are a significant reservoir of anthropogenic activities which have a strong negative effect on several phytosociological, pedochemical and biological parameters. Compared with conventional mechanical mowing, chemical treatment induced (i) a significant increase in organic matter in the upper plot layers (+18%), and (ii) a marked reduction in weed height throughout the entire period of the experiment. Irrespectively of the kind of treatment, no significance differences were detected in terms of (i) biological quality of soil (the abundance and diversity of arthropod communities did not change), and (ii) plant elemental content (bulk concentrations of analysed trace elements had a good fit within ranges of occurrence in the "reference plant"). The glyphosate partially controlled broad-leaved weeds and this moderate efficacy is dependent upon the season/time of application. In conclusion, the rational and sustainable use of chemical herbicides may be a useful tool for the management of roadside vegetation. PMID:26573685

  2. In vitro cellular responses to silicon carbide nanoparticles: impact of physico-chemical features on pro-inflammatory and pro-oxidative effects

    Energy Technology Data Exchange (ETDEWEB)

    Pourchez, Jeremie, E-mail: pourchez@emse.fr; Forest, Valerie [LINA EA 4624, Ecole Nationale Superieure des Mines, CIS-EMSE (France); Boumahdi, Najih; Boudard, Delphine [SFR IFRESIS (France); Tomatis, Maura; Fubini, Bice [Universita di Torino, Dipartimento di Chimica and ' G. Scansetti' Interdepartmental Center for Studies on Asbestos and other Toxic Particulates (Italy); Herlin-Boime, Nathalie; Leconte, Yann [Service des Photons, Atomes et Molecules, CEA-CNRS URA2453, IRAMIS, CEA SACLAY, Laboratoire Francis Perrin (France); Guilhot, Bernard; Cottier, Michele; Grosseau, Philippe [SFR IFRESIS (France)

    2012-10-15

    Silicon carbide is an extremely hard, wear resistant, and thermally stable material with particular photoluminescence and interesting biocompatibility properties. For this reason, it is largely employed for industrial applications such as ceramics. More recently, nano-sized SiC particles were expected to enlarge their use in several fields such as composite supports, power electronics, biomaterials, etc. However, their large-scaled development is restricted by the potential toxicity of nanoparticles related to their manipulation and inhalation. This study aimed at synthesizing (by laser pyrolysis or sol-gel methods), characterizing physico-chemical properties of six samples of SiC nanopowders, then determining their in vitro biological impact(s). Using a macrophage cell line, toxicity was assessed in terms of cell membrane damage (LDH release), inflammatory effect (TNF-{alpha} production), and oxidative stress (reactive oxygen species generation). None of the six samples showed cytotoxicity while remarkable pro-oxidative reactions and inflammatory response were recorded, whose intensity appears related to the physico-chemical features of nano-sized SiC particles. In vitro data clearly showed an impact of the extent of nanoparticle surface area and the nature of crystalline phases ({alpha}-SiC vs. {beta}-SiC) on the TNF-{alpha} production, a role of surface iron on free radical release, and of the oxidation state of the surface on cellular H{sub 2}O{sub 2} production.

  3. Scrutinizing impacts of conspiracy theories on readers' political views: a rational choice perspective on anti-semitic rhetoric in Turkey.

    Science.gov (United States)

    Nefes, Turkay Salim

    2015-09-01

    Although conspiracy theories have been politically significant throughout history, only a few empirical studies have been about their influence on readers' views. Combining a rational choice approach with a content analysis of an anti-Semitic best-selling conspiracy theory book series in Turkey - the Efendi series - and semi-structured interviews with its readers, this paper reveals the effects of the conspiracy theories on readers' political perspectives. The findings suggest that whereas the rightists are reactive to the Jewish origins of the Dönmes, the leftists oppose the Dönmes as dominant bourgeois figures. This paper concludes that left- and right-wing adherents use the conspiratorial accounts in line with their political views and ontological insecurities. It expands the existing academic literature, which conceptualizes conspiracy theories either as paranoid delusions or as neutral, rational narratives, by showing that they can be both.

  4. Scrutinizing impacts of conspiracy theories on readers' political views: a rational choice perspective on anti-semitic rhetoric in Turkey.

    Science.gov (United States)

    Nefes, Turkay Salim

    2015-09-01

    Although conspiracy theories have been politically significant throughout history, only a few empirical studies have been about their influence on readers' views. Combining a rational choice approach with a content analysis of an anti-Semitic best-selling conspiracy theory book series in Turkey - the Efendi series - and semi-structured interviews with its readers, this paper reveals the effects of the conspiracy theories on readers' political perspectives. The findings suggest that whereas the rightists are reactive to the Jewish origins of the Dönmes, the leftists oppose the Dönmes as dominant bourgeois figures. This paper concludes that left- and right-wing adherents use the conspiratorial accounts in line with their political views and ontological insecurities. It expands the existing academic literature, which conceptualizes conspiracy theories either as paranoid delusions or as neutral, rational narratives, by showing that they can be both. PMID:26174172

  5. MFGA-IDT2 workshop: Astrophysical and geophysical fluid mechanics: the impact of data on turbulence theories

    Science.gov (United States)

    Schertzer, D.; Falgarone, E.

    very large scale of the Universe. The presentations and the round table at the end of the workshop pointed out the following: - the necessity of this type of confrontation which makes intervene numerical simulations, laboratory experiments, phenomenology as well as a very large diversity of geophysical and astrophysical data, - presumably a relative need for new geophysical data, whereas there have been recent astrophysical experiments which yield interesting data and exciting questions; - the need to develop a closer intercomparison between various intermittency models (in particular Log-Poisson /Log Levy models). Two main questions were underlined, in particular during the round table: - the behaviour of the extremes of intermittency, in particular the question of divergence or convergence of the highest statistical moments (equivalently, do the probability distributions have algebraic or more rapid falloffs?); - the extension of scaling ranges; in other words do we need to divide geophysics and astrophysics in many small (nearly) isotropic subranges or is it sufficient to use anisotropic scaling notions over wider ranges? 4 The contributions in this special issue Recalling that some of the most useful insights into the nature of turbulence in fluids have come from observations of geophysical flows, Van Atta gives a review of the impacts of geophysical turbulence data into theories. His paper starts from Taylor's inference of the nearly isotropy of atmospheric turbulence and the corresponding elegant theoretical developments by von Karman of the theory of isotropic turbulence, up to underline the fact that the observed extremely large intermittency in geophysical turbulence also raised new fundamental questions for turbulence theory. The paper discusses the potential contribution to theoretical development from the available or currently being made geophysical turbulence measurements, as well as from some recent laboratory measurements and direct numerical

  6. Identifying military impacts on archaeology deposits based on differences in soil organic carbon and chemical elements at soil horizon interfaces

    Science.gov (United States)

    The National Historic Preservation Act requires land-managing agencies to identify and account for their impacts on archaeological resources. Regulatory agencies that oversee compliance with historic preservation legislation frequently assume military training adversely affects archaeological resou...

  7. A framework incorporating the impact of exposure scenarios and application conditions on risk assessment of chemicals applied to skin

    OpenAIRE

    Dancik, Yuri; Troutman, John A; Jaworska, Joanna

    2013-01-01

    Purpose 1. To develop a framework for exposure calculation via the dermal route to meet the needs of 21st century toxicity testing and refine current approaches; 2. To demonstrate the impact of exposure scenario and application conditions on the plasma concentration following dermal exposure. Method A workflow connecting a dynamic skin penetration model with a generic whole-body physiologically-based pharmacokinetic (PBPK) model was developed. The impact of modifying exposure scenarios and ap...

  8. Impacts

    NARCIS (Netherlands)

    Hellmuth, M.; Kabat, P.

    2003-01-01

    Even without the impacts of climate change, water managers face prodigious challenges in meeting sustainable development goals. Growing populations need affordable food, water and energy. Industrial development demands a growing share of water resources and contaminates those same resources with its

  9. A synthetic method for atmospheric diffusion simulation and environmental impact assessment of accidental pollution in the chemical industry in a WEBGIS context.

    Science.gov (United States)

    Ni, Haochen; Rui, Yikang; Wang, Jiechen; Cheng, Liang

    2014-09-01

    The chemical industry poses a potential security risk to factory personnel and neighboring residents. In order to mitigate prospective damage, a synthetic method must be developed for an emergency response. With the development of environmental numeric simulation models, model integration methods, and modern information technology, many Decision Support Systems (DSSs) have been established. However, existing systems still have limitations, in terms of synthetic simulation and network interoperation. In order to resolve these limitations, the matured simulation model for chemical accidents was integrated into the WEB Geographic Information System (WEBGIS) platform. The complete workflow of the emergency response, including raw data (meteorology information, and accident information) management, numeric simulation of different kinds of accidents, environmental impact assessments, and representation of the simulation results were achieved. This allowed comprehensive and real-time simulation of acute accidents in the chemical industry. The main contribution of this paper is that an organizational mechanism of the model set, based on the accident type and pollutant substance; a scheduling mechanism for the parallel processing of multi-accident-type, multi-accident-substance, and multi-simulation-model; and finally a presentation method for scalar and vector data on the web browser on the integration of a WEB Geographic Information System (WEBGIS) platform. The outcomes demonstrated that this method could provide effective support for deciding emergency responses of acute chemical accidents.

  10. A synthetic method for atmospheric diffusion simulation and environmental impact assessment of accidental pollution in the chemical industry in a WEBGIS context.

    Science.gov (United States)

    Ni, Haochen; Rui, Yikang; Wang, Jiechen; Cheng, Liang

    2014-09-01

    The chemical industry poses a potential security risk to factory personnel and neighboring residents. In order to mitigate prospective damage, a synthetic method must be developed for an emergency response. With the development of environmental numeric simulation models, model integration methods, and modern information technology, many Decision Support Systems (DSSs) have been established. However, existing systems still have limitations, in terms of synthetic simulation and network interoperation. In order to resolve these limitations, the matured simulation model for chemical accidents was integrated into the WEB Geographic Information System (WEBGIS) platform. The complete workflow of the emergency response, including raw data (meteorology information, and accident information) management, numeric simulation of different kinds of accidents, environmental impact assessments, and representation of the simulation results were achieved. This allowed comprehensive and real-time simulation of acute accidents in the chemical industry. The main contribution of this paper is that an organizational mechanism of the model set, based on the accident type and pollutant substance; a scheduling mechanism for the parallel processing of multi-accident-type, multi-accident-substance, and multi-simulation-model; and finally a presentation method for scalar and vector data on the web browser on the integration of a WEB Geographic Information System (WEBGIS) platform. The outcomes demonstrated that this method could provide effective support for deciding emergency responses of acute chemical accidents. PMID:25198686

  11. A Synthetic Method for Atmospheric Diffusion Simulation and Environmental Impact Assessment of Accidental Pollution in the Chemical Industry in a WEBGIS Context

    Directory of Open Access Journals (Sweden)

    Haochen Ni

    2014-09-01

    Full Text Available The chemical industry poses a potential security risk to factory personnel and neighboring residents. In order to mitigate prospective damage, a synthetic method must be developed for an emergency response. With the development of environmental numeric simulation models, model integration methods, and modern information technology, many Decision Support Systems (DSSs have been established. However, existing systems still have limitations, in terms of synthetic simulation and network interoperation. In order to resolve these limitations, the matured simulation model for chemical accidents was integrated into the WEB Geographic Information System (WEBGIS platform. The complete workflow of the emergency response, including raw data (meteorology information, and accident information management, numeric simulation of different kinds of accidents, environmental impact assessments, and representation of the simulation results were achieved. This allowed comprehensive and real-time simulation of acute accidents in the chemical industry. The main contribution of this paper is that an organizational mechanism of the model set, based on the accident type and pollutant substance; a scheduling mechanism for the parallel processing of multi-accident-type, multi-accident-substance, and multi-simulation-model; and finally a presentation method for scalar and vector data on the web browser on the integration of a WEB Geographic Information System (WEBGIS platform. The outcomes demonstrated that this method could provide effective support for deciding emergency responses of acute chemical accidents.

  12. Application of fisheries management techniques to assessing impacts: task I report. [Assessment of chemical, radiological, and thermal impacts of nuclear power plants on fish populations

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, D.H.; Baker, K.S.; Fickeisen, D.H.; Metzger, R.M.; Skalski, J.R.

    1979-03-01

    Task I efforts examined the available fisheries management techniques and assessed their potential application in a confirmatory monitoring program. The objective of such monitoring programs is to confirm that the prediction of an insignificant impact (usually made in the FES) was correct. Fisheries resource managers have developed several tools for assessing the fish population response to stress (exploitation) and they were thought potentially useful for detecting nuclear power plant impacts. Techniques in three categories were examined; catch removal, population dynamics, and nondestructive censuses, and the report contains their description, examples of application, advantages, and disadvantages. The techniques applied at nuclear power plant sites were examined in detail to provide information on implementation and variability of specific approaches. The most suitable techniques to incorporate into a monitoring program confirming no impact appear to be those based on Catch Per Unity Effort (CPUE) and hydroacoustic data. In some specific cases, age and growth studies and indirect census techniques may be beneficial. Recommendations for task II efforts to incorporate these techniques into monitoring program designs are presented. These include development of guidelines for; (1) designing and implementing a data collection program; (2) interpreting these data and assessing the occurrence of impact, and (3) establishment of the monitoring program's ability to detect changes in the affected populations.

  13. Demystifying a Black Box: A Grounded Theory of How Travel Experiences Impact the Jewish Identity Development of Jewish Emerging Adults

    Science.gov (United States)

    Aaron, Scott

    2015-01-01

    The positive impact on the Jewish Identity Development of Jewish Emerging Adults of both the 10 day trips to Israel popularly known as Birthright trips and the service learning trips commonly known as Alternative Spring Breaks has been well-documented. However, the mechanics of how this positive impact occurs has not been well-understood. This…

  14. Radiation thermo-chemical models of protoplanetary discs : III. Impact of inner rims on spectral energy distributions

    NARCIS (Netherlands)

    Thi, W. -F.; Woitke, P.; Kamp, I.

    2011-01-01

    We study the hydrostatic density structure of the inner disc rim around Herbig Ae stars using the thermo-chemical hydrostatic code prodimo. We compare the spectral energy distributions (SEDs) and images from our hydrostatic disc models to that from prescribed density structure discs. The 2D continuu

  15. Evaluating the Impact of Uncertainties in Clearance and Exposure When Prioritizing Chemicals Screened in High-Throughput Assays

    Science.gov (United States)

    The toxicity-testing paradigm has evolved to include high-throughput (HT) methods for addressing the increasing need to screen hundreds to thousands of chemicals rapidly. Approaches that involve in vitro screening assays, in silico predictions of exposure concentrations, and phar...

  16. Bio-based targeted chemical engineering education : Role and impact of bio-based energy and resourcedevelopment projects

    NARCIS (Netherlands)

    Márquez Luzardoa, N.M.; Venselaar, Jan

    2012-01-01

    Avans University of Applied Sciences is redrafting its courses and curricula in view of sustainability. For chemical engineering in particular that implies a focus on 'green' and bio-based processes, products and energy. Avans is situated in the Southwest region of the Netherlands and specifically i

  17. Impact of thickness of GaN buffer layer on properties of AlN/GaN distributed Bragg reflectors grown by metalorganic chemical vapor deposition

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We studied the impact of the thickness of GaN buffer layer on the properties of distributed Bragg reflector (DBR) grown by metalorganic chemical vapor deposition (MOCVD). The samples were characterized by using metallographic microscope, transmission electron microscope (TEM), atomic force microscopy (AFM), X-ray diffractometer (XRD) and spectrophotometer. The results show that the thickness of the GaN buffer layer can significantly affect the properties of the DBR structure and there is an optimal thickness of the GaN buffer layer. This work would be helpful for the growth of high quality DBR structures.

  18. IMPACTS !

    CERN Multimedia

    2008-01-01

    (Photo courtesy of Don Davis / NASA)The University of Geneva (UNIGE) and the Ecole Polytechnique Fédérale of Lausanne (EPFL) are organising the 4th series of public lectures on astronomy, on the theme of "Impacts". The schedule is as follows: Il y a 100 ans : une explosion dans la Tunguska – Dr. Frédéric COURBIN, EPFL Les impacts sur Terre – Prof. Didier Queloz, UNIGE La fin des dinosaures – Dr. Stéphane Paltani, UNIGE Wednesday 7 May 2008, from 7.00 p.m. to 9.00 p.m. Auditoire CO1, EPFL, Ecublens Thursday 08 May 2008, from 7.00 p.m. to 9.00 p.m. Auditoire Rouiller, Uni-Dufour, Genève All 3 lectures will be givent each evening! Admission free Information: 022 379 22 00

  19. The Impact of Rawls and MacIntyre Theory of Justice on National Cohesion in Multicultural Societies

    Directory of Open Access Journals (Sweden)

    Sara Najafpour

    2013-07-01

    Full Text Available Today, many countries have differences ethnic, subcultures, communities and religions. Managing and making policy in this society is more difficult than en bloc societies. Therefore one of more important of their problems is making just policies, which create and preserve national cohesion. To achieving this purpose, their governments try to use a justice theory, which can apply justice among people and preserve national cohesion. There is several justice theories that may help to these kinds of societies, and each society based on its own positions select and perform one of them. Among different theory of justice, this essay studies Rawls and Macintyre theory of justice, because They play a huge role in shaping political philosophy, and also they represent two major contemporary political streams like liberalism and communitarians. The main question that this essay tries to follow is which theories of justice could be useful in multicultural society and cause to create national cohesion. This essay use descriptive and analysis method.

  20. Understanding the conformational impact of chemical modifications on monoclonal antibodies with diverse sequence variation using hydrogen/deuterium exchange mass spectrometry and structural modeling.

    Science.gov (United States)

    Zhang, Aming; Hu, Ping; MacGregor, Paul; Xue, Yu; Fan, Haihong; Suchecki, Peter; Olszewski, Leonard; Liu, Aston

    2014-04-01

    Chemical modifications can potentially induce conformational changes near the modification site and thereby impact the safety and efficacy of protein therapeutics. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) has emerged as a powerful analytical technique with high spatial resolution and sensitivity in detecting such local conformational changes. In this study, we utilized HDX-MS combined with structural modeling to examine the conformational impact on monoclonal antibodies (mAbs) caused by common chemical modifications including methionine (Met) oxidation, aspartic acid (Asp) isomerization, and asparagine (Asn) deamidation. Four mAbs with diverse sequences and glycosylation states were selected. The data suggested that the impact of Met oxidation was highly dependent on its location and glycosylation state. For mAbs with normal glycosylation in the Fc region, oxidation of the two conserved Met252 and Met428 (Kabat numbering) disrupted the interface interactions between the CH2 and CH3 domains, thus leading to a significant decrease in CH2 domain thermal stability as well as a slight increase in aggregation propensity. In contrast, Met oxidation in the variable region and CH3 domain had no detectable impact on mAb conformation. For aglycosylated mAb, Met oxidation could cause a more global conformational change to the whole CH2 domain, coincident with the larger decrease in thermal stability and significant increase in aggregation rate. Unlike Met oxidation, Asn deamidation and Asp isomerization mostly had very limited effects on mAb conformation, with the exception of succiminide intermediate formation which induced a measurable local conformational change to be more solvent protected. Structural modeling suggested that the succinimide intermediate was stabilized by adjacent aromatic amino acids through ring-ring stacking interactions. PMID:24597564

  1. Business strategy: Obstacles to the consolidation of Digital TV in Brazil and its impact on electronics supply chain from the stakeholder theory view

    Directory of Open Access Journals (Sweden)

    Roberto Bazanini

    2014-04-01

    Full Text Available With the introduction of digital TV in Brazil on December 2, 2007, the managers of the electronics industry, of course, waiting for impacts in the supply chain due to the promise of strong eating of the market. According with exploratory research, qualitative and in-depth interview with the executives of the electronics industry, the research objectivist diagnose the obstacles to consolidation of digital TV in Brazil and its possible strategic changes with the emergence of a new scenario resulting from the expectations that were in the Brazilian market and its implications in terms of a new configuration of complex electronics in the stakeholder theory view. The survey results indicate that, in the perception of respondents, while sales of digital TV have grown sharply in the past two years, from the perspective of industry executives from electronics, the process is not yet consolidated, provided the expectations did not materialize and hence the impact on the supply chain regarding the impact that digital TV would cause this industry sat a level below that expected by technical factors and associated mainly to the lack of integration with stakeholders definitive represented by broadcasters and the federal government. The contribution of the research is to discuss the applicability of the theory stakeholder’s theory in the telecommunications sector in it’s economic, technical and political. The limitations of the work lies in the small number of subjects studied and emphasis on only one of the agents involved and analyzes the process of consolidation of Digital TV in Brazil from the perspective of the consumer electronics industry executives, so it is suggested for future research studies with other agents developers.

  2. How Does Anxiety Impact on SLA:with Particular Reference to Krashen's Theory of the Affective Filter

    Institute of Scientific and Technical Information of China (English)

    徐骏

    2013-01-01

      The overall proposition of this paper is taking a deeper look into the impact, especially the negative one, that anxiety or to be specific language anxiety has placed in the process of students' language learning.

  3. How Does Anxiety Impact on SLA:with Particular Reference to Krashen's Theory of the Affective Filter

    Institute of Scientific and Technical Information of China (English)

    徐骏

    2013-01-01

    The overall proposition of this paper is taking a deeper look into the impact,especially the negative one,that anxiety or to be specific language anxiety has placed in the process of students' language learning.

  4. Impact of the neutron and nuclear matter equations of state on neutron skin and neutron drip lines in chiral effective field theory

    CERN Document Server

    Sammarruca, Francesca

    2016-01-01

    We present predictions of the binding energy per nucleon and the neutron skin thickness in highly neutron-rich isotopes of Oxygen, Magnesium, and Aluminum. The calculations are carried out at and below the neutron drip line. The nuclear properties are obtained via an energy functional whose input is the equation of state of isospin-asymmetric in?finite matter. The latter is based on a microscopic derivation applying chiral few-nucleon forces. We highlight the impact of the equation of state at diff?erent orders of chiral effective fi?eld theory and discuss the role of three-neutron forces.

  5. Impact of chemical treatments on the mechanical and water absorption properties of coconut fibre (Cocos nucifera reinforced polypropylene composites

    Directory of Open Access Journals (Sweden)

    Isiaka O. OLADELE

    2016-07-01

    Full Text Available In this work, chemically treated coconut fibres were used to reinforce Homopolymer Polypropylene in order to ascertain the effect of the treatments on the mechanical and water absorption properties of the composites produced. Coconut fibre was first extracted from its husk by soaking it in water and was dried before it was cut into 10 mm lengths. It was then chemically treated in alkali solution of sodium hydroxide (NaOH and potassium hydroxide (KOH in a shaker water bath. The treated coconut fibres were used as reinforcements in polypropylene matrix to produce composites of varied fibre weight contents; 2, 4, 6, 8 and 10 wt.%. Tensile and flexural properties were investigated using universal testing machine while water absorption test was carried out on the samples for 7 days. It was observed from the results that, NaOH treated samples gave the best tensile properties while KOH treated samples gave the best flexural and water repellent properties.

  6. Impact of Microwave Treatment on Chemical Constituents in Fresh Rhizoma Gastrodiae (Tianma by UPLC-MS Analysis

    Directory of Open Access Journals (Sweden)

    Qimeng Fan

    2014-01-01

    Full Text Available Fresh Rhizoma Gastrodiae (Tianma was processed in a microwave oven at 2450 MHz in order to study the effect on the main chemical component changes taking place during microwave treatment. It was found that microwave affected the chemical composition of Tianma. Seven compounds, including gastrodin, gastrodigenin (p-hydroxybenzylalcohol, p-hydroxybenzaldehyde, vanillyl alcohol, vanillin, adenine, and 5-hydroxymethylfurfural, were identified in this study. As major active compounds, the contents of gastrodin and gastrodigenin in MWT Tianma were both twice as much as those in raw Tianma. Besides, the MS data show that there are still some unidentified compositions in Tianma, and there are also many converted compounds in MWT Tianma, which is worthy of further work. The results have indicated that microwave treated fresh Tianma might be helpful in designing the processing of traditional Chinese medicine and the application of microwave technology in traditional Chinese medicine needs to be researched further in the future.

  7. Health and Natural Resources: The Extraction of Useful Chemicals from Plants and their Impact on Socio-Economic Development

    International Nuclear Information System (INIS)

    Poverty reduction strategies in developing countries are based on the need to develop and improve the quality of life of people. The successful strategies link wealth creating activities of adding value to local resources with employment creation. These strategies lead to increased capacity to produce needed consumer goods such as food, fuel, construction materials, textiles and pharmaceuticals starting from local resources. Most value-adding transformations of materials to consumer goods use chemicals conversion processes

  8. EIA THEORIES — ALL CHINESE WHISPERS AND NO CRITICAL THEORY

    OpenAIRE

    JOE WESTON

    2010-01-01

    There have been a large number of attempts to develop a theory or theories of Environmental Impact Assessment in order to justify its use in environmental decision-making. A review of academic articles demonstrates that these theories are largely drawn from planning theories. Planning theories are themselves a development of sociological theories of decision-making and from one particular strand of sociological theory. In this review of the theories of EIA it is argued that an understanding o...

  9. Impacts of rice plant roots on the variation in electro-physico-chemical properties of soil waters

    International Nuclear Information System (INIS)

    Lowland rice crop is cultivated under continuous flooding and anaerobic conditions but rhizospheric region of the rice plants can have different physico-chemical conditions than in the absence of roots. However, it is very difficult to measure all physico-chemical parameters instantaneously in the rhizos phere because this region, being highly dynamic, altering rapidly those parameters of surrounding soil waters. Present study has compared the evolution of electro-physico-chemical properties (pH, redox potentials (pe), Electrical Conductivity (EC) and temperature) of soil waters during a complete day at two different phenological stages in the presence of rice roots (rhizosphere) and in the absence of roots to analyse the effect of rhizosphere on soil waters. In the rhizosphere, pH of soil waters was found comparatively low (7). Similarly, small EC values were observed in the rhizosphere. Great fluctuations (diurnal patterns) were observed during the complete days which were directly associated to atmospheric conditions (temperature and light) and rhizospheric activity, and these fluctuations were more during vegetative phase as compared to maturation stage of rice. It was also observed that incorporation of crop residues resulted in the more reductive conditions in the rice culture. (author)

  10. Impact of Learned Resourcefulness and Theories of Intelligence on Academic Achievement of University Students: An Integrated Approach

    Science.gov (United States)

    Kennett, Deborah J.; Keefer, Kateryna

    2006-01-01

    This was the first study to integrate Rosenbaum's concept of learned resourcefulness with Dweck's implicit theories of intelligence in predicting university students' academic self-control behaviour and year-end grades. Rosenbaum highlights the prominent role that learned resourcefulness skills play in promoting mastery responses and goal…

  11. 'A Theory of the Allocation of Time' Turns Fifty: Its Impact on the Field of Health Economics.

    Science.gov (United States)

    Grossman, Michael

    2016-01-01

    The year 2015 is the 50th anniversary of the publication of 'A Theory of the Allocation of Time,' by Gary S. Becker in the 1965 volume of The Economic Journal. To mark that occasion, this editorial focuses on the importance of that paper in the history and evolution of the field of health economics.

  12. The Provenances of Economic Theory's Impact on Education: French Educational Thought at the End of the Ancien Regime

    Science.gov (United States)

    Gilead, Tal

    2011-01-01

    Today, the influence of economic thought on educational theory is evident. It seems to weaken, however, the further we travel back in history. In this article, Tal Gilead examines the historical origins of this influence. He shows that it first emerged in French educational thought during the second half of the eighteenth century. Through…

  13. The impact of variations of influent loading on the efficacy of an advanced tertiary sewage treatment plant to remove endocrine disrupting chemicals.

    Science.gov (United States)

    Hamilton, Lisa A; Tremblay, Louis A; Northcott, Grant L; Boake, Michael; Lim, Richard P

    2016-08-01

    The impact of changes in influent load on the removal of endocrine disrupting chemicals (EDCs) by sewage treatment has not been fully characterised. This study assessed the efficacy of an advanced tertiary sewage treatment plant (STP) to remove EDCs during normal and peak flow events of sewage influent using trace chemical analysis of selected EDCs and four estrogenic in vitro bioassays. During the summer holiday season, influent volume increased by 68%, nutrient concentrations by at least 26% and hydraulic retention time was reduced by 40% compared with base flow conditions. Despite these pressures on the treatment system the concentrations and mass loading of estrone, 17β-estradiol, estriol, Bisphenol A, 4-t-octylphenol and technical nonylphenol were not significantly higher (p>0.05) during the peak flow conditions compared with base flow conditions. Chemical analysis and in vitro bioassays showed that the efficacy of the STP in removing EDCs was not affected by the different loadings between baseline and peak flow regimes. This study demonstrates that large flow variations within the design capacity of advanced multi-stage STPs should not reduce the removal efficacy of EDCs.

  14. The impact of variations of influent loading on the efficacy of an advanced tertiary sewage treatment plant to remove endocrine disrupting chemicals.

    Science.gov (United States)

    Hamilton, Lisa A; Tremblay, Louis A; Northcott, Grant L; Boake, Michael; Lim, Richard P

    2016-08-01

    The impact of changes in influent load on the removal of endocrine disrupting chemicals (EDCs) by sewage treatment has not been fully characterised. This study assessed the efficacy of an advanced tertiary sewage treatment plant (STP) to remove EDCs during normal and peak flow events of sewage influent using trace chemical analysis of selected EDCs and four estrogenic in vitro bioassays. During the summer holiday season, influent volume increased by 68%, nutrient concentrations by at least 26% and hydraulic retention time was reduced by 40% compared with base flow conditions. Despite these pressures on the treatment system the concentrations and mass loading of estrone, 17β-estradiol, estriol, Bisphenol A, 4-t-octylphenol and technical nonylphenol were not significantly higher (p>0.05) during the peak flow conditions compared with base flow conditions. Chemical analysis and in vitro bioassays showed that the efficacy of the STP in removing EDCs was not affected by the different loadings between baseline and peak flow regimes. This study demonstrates that large flow variations within the design capacity of advanced multi-stage STPs should not reduce the removal efficacy of EDCs. PMID:27096490

  15. The impact of a novel herbal Shirazi Thymus Vulgaris on primary dysmenorrhea in comparison to the classical chemical Ibuprofen

    OpenAIRE

    Ashraf Direkvand-Moghadam; Afra Khosravi

    2012-01-01

    Objective: Primary dysmenorrhea is defined as painful cramps during menstruation with no pelvic pathology. Due to the adverse effects of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are considered as the most common pharmacological treatment for this disorder. The present study was conducted to assess the impact of Shirazi Thymus Vulgaris compared to that of Ibuprofen on primary dysmenorrhea. Materials and Methods: A randomized, single-blind clinical trial was conducted amongst 120 female s...

  16. Impact analysis of the implemented quality management system on business performances in pharmaceutical-chemical industry in Serbia

    Directory of Open Access Journals (Sweden)

    Marinković Valentina D.

    2013-01-01

    Full Text Available International quality management standard (QMS ISO 9001 became widely accepted as a framework for product and/or services quality improvement. There are recent research conducted in order to define relationships and effects between the applied QMS and financial and/or non-financial business parameters. The effects of the applied pharmaceutical quality system (PQS on the business performances in Serbian pharmaceutical-chemical industry are analyzed in this paper using multivariate linear regression analysis. The empirical data were collected using a survey that was performed among experts from Serbian pharmaceutical-chemical industrial sector during 2010. An extensive questionnaire was used in the survey, grouping the questions in eight groups: Implementation of pharmaceutical quality system (AQ, Quality/strategy planning (QP, Human resource management (HR, Supply management (SM, Customer focus (CF, Process management (PM, Continuous improvement (CI, and Business results (BR. The primary goal of the research was to analyze the effects of the elements of first seven groups (AQ, QP, HR, SM, CF, PM, and CI that present various aspects of the implementation of PQS, on the elements of business results (BR. Based on empirical data, regression relations were formed to present the effects of all considered elements of PQS implementation on the business performance parameters (BR. The positive effects of PQS implementation on the business performances such as the assessment of performance indicators, continual products and/or services quality improvement, and efficient problem solving, are confirmed in the presented research for the Serbian pharmaceutical-chemical industrial sector. The results of the presented research will create a room for the improvement of the existing models in application, and for attracting interested parties that aim to commence this business standardization process. Hence, implementation of PQS is not only the regulatory

  17. Impact of annealing on the chemical structure and morphology of the thin-film CdTe/ZnO interface

    Energy Technology Data Exchange (ETDEWEB)

    Horsley, K., E-mail: horsley5@unlv.nevada.edu; Hanks, D. A.; Weir, M. G. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, Nevada 89154 (United States); Beal, R. J. [Materials Science and Engineering Department, University of Arizona, Tucson, Arizona 85721 (United States); Wilks, R. G. [Solar Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), 14109 Berlin (Germany); Blum, M. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, Nevada 89154 (United States); Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Häming, M. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, Nevada 89154 (United States); Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); Hofmann, T. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, Nevada 89154 (United States); Bundeswehr Research Institute for Materials, Fuels and Lubricants (WIWeB), Institutsweg 1, 85435 Erding (Germany); Weinhardt, L. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, Nevada 89154 (United States); Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); and others

    2014-07-14

    To enable an understanding and optimization of the optoelectronic behavior of CdTe-ZnO nanocomposites, the morphological and chemical properties of annealed CdTe/ZnO interface structures were studied. For that purpose, CdTe layers of varying thickness (4–24 nm) were sputter-deposited on 100 nm-thick ZnO films on surface-oxidized Si(100) substrates. The morphological and chemical effects of annealing at 525 °C were investigated using X-ray Photoelectron Spectroscopy (XPS), X-ray-excited Auger electron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, and atomic force microscopy. We find a decrease of the Cd and Te surface concentration after annealing, parallel to an increase in Zn and O signals. While the as-deposited film surfaces show small grains (100 nm diameter) of CdTe on the ZnO surface, annealing induces a significant growth of these grains and separation into islands (with diameters as large as 1 μm). The compositional change at the surface is more pronounced for Cd than for Te, as evidenced using component peak fitting of the Cd and Te 3d XPS peaks. The modified Auger parameters of Cd and Te are also calculated to further elucidate the local chemical environment before and after annealing. Together, these results suggest the formation of tellurium and cadmium oxide species at the CdTe/ZnO interface upon annealing, which can create a barrier for charge carrier transport, and might allow for a deliberate modification of interface properties with suitably chosen thermal treatment parameters.

  18. Linking invasive exotic vertebrates and their ecosystem impacts in Tierra del Fuego to test theory and determine action

    Science.gov (United States)

    Valenzuela, Alejandro E. J.; Anderson, Christopher B.; Fasola, Laura; Cabello, José L.

    2014-01-01

    Understanding processes and impacts of biological invasions is fundamental for ecology and management. Recent reviews summarized the mechanisms by which invasive species alter entire ecosystems, but quantitative assessments of these mechanisms are lacking for actual assemblages to determine their relative importance, frequency and patterns. We updated information on introduced vertebrates in the Tierra del Fuego Archipelago (TDF) via an exhaustive literature review and new data to evaluate ecosystem impact mechanisms and provide management recommendations. To date, 24 exotic vertebrates have naturalized in TDF, outnumbering natives nearly 2:1, with the North American beaver (Castor canadensis) and muskrat (Ondatra zibethica) being the most widely distributed species and also impacting the ecosystem through the greatest number of mechanisms. Introduced vertebrates occupied most parts of the archipelago with human-inhabited islands having greater taxa richness. All exotics potentially altered ecosystems by one or more mechanisms: 100% food webs, 92% invasional meltdown, 42% habitat modification, 38% disease or parasite transmission, 21% soil property and disturbance regime changes. Impact to habitat structure was the main clustering criterion for this assemblage. Within the species that physically alter habitats, we found two sub-groups: 1) large herbivores and 2) "others" including beavers and muskrats. Species that did not alter habitat were divided further into those with predatory trophic effects (carnivorous mammals and trout, sub-group 4) and the rest with assorted impacts (sub-group 3). By establishing high quality information on archipelago-wide assemblage, distribution, impacts and mechanisms for exotic vertebrates, we recommend, based on ecological criteria, prioritizing the management of sub-group 2. A secondary priority might be given to the carnivores in sub-group 4, while species in sub-groups 1 and 3 are less urgent. As the first systematic survey of

  19. A method to study the impact of chemically-induced ovarian failure on exercise capacity and cardiac adaptation in mice.

    Science.gov (United States)

    Chen, Hao; Perez, Jessica N; Constantopoulos, Eleni; McKee, Laurel; Regan, Jessica; Hoyer, Patricia B; Brooks, Heddwen L; Konhilas, John

    2014-04-07

    The risk of cardiovascular disease (CVD) increases in post-menopausal women, yet, the role of exercise, as a preventative measure for CVD risk in post-menopausal women has not been adequately studied. Accordingly, we investigated the impact of voluntary cage-wheel exercise and forced treadmill exercise on cardiac adaptation in menopausal mice. The most commonly used inducible model for mimicking menopause in women is the ovariectomized (OVX) rodent. However, the OVX model has a few dissimilarities from menopause in humans. In this study, we administered 4-vinylcyclohexene diepoxide (VCD) to female mice, which accelerates ovarian failure as an alternative menopause model to study the impact of exercise in menopausal mice. VCD selectively accelerates the loss of primary and primordial follicles resulting in an endocrine state that closely mimics the natural progression from pre- to peri- to post-menopause in humans. To determine the impact of exercise on exercise capacity and cardiac adaptation in VCD-treated female mice, two methods were used. First, we exposed a group of VCD-treated and untreated mice to a voluntary cage wheel. Second, we used forced treadmill exercise to determine exercise capacity in a separate group VCD-treated and untreated mice measured as a tolerance to exercise intensity and endurance.

  20. Terror management theory and the impact of individual and collective mortality salience on symbolic and literal immortality beliefs

    OpenAIRE

    Conrad, Brent

    2009-01-01

    According to Terror Management Theory (TMT), many human behaviors, attitudes, and thoughts are the result of an attempt to reduce the uncomfortable feelings associated with the knowledge that human life is finite. Although many of TMT’s postulates have been supported by research, the assumption that an underlying desire for literal or symbolic immortality is partly responsible for mortality salience responses has received less research attention. Additionally, there has been little research i...

  1. ECF BLEACHING WITH A FINAL HYDROGEN PEROXIDE STAGE: IMPACT ON THE CHEMICAL COMPOSITION OF Eucalyptus globulus KRAFT PULPS

    Directory of Open Access Journals (Sweden)

    Pedro E. G. Loureiro

    2010-11-01

    Full Text Available Two industrial elemental chlorine free (ECF bleaching sequences, D0(EOPD1(EPD2 and OQ(PODP, are compared with respect to the bulk content of lignin, carboxyl, hexeneuronic acids (HexA, and reducing groups after each bleaching stage. HexA groups contribute significantly to the total content of carboxyl groups, and their degradation during chlorine dioxide bleaching is reflected by a decrease of the carboxyl content. The higher degradation using an enhanced use of oxygen-based bleaching chemicals is associated with a higher fiber charge reduction, mainly due to xylan depletion. Additionally, the effect of process variables of a laboratory final hydrogen peroxide stage on the chemical composition of the fully bleached pulp (D0(EOPD1P and OQ(PODP is studied. The ability of final peroxide bleaching to raise the content of carboxyl groups is dependent on the operating conditions and pulp bleaching history. A balance between carbohydrate oxidation and dissolution of oxidized groups determines the effect on fiber charge. The effect of hydrogen peroxide stabilizers added into the final stage on the content of carboxyl groups is also reported.

  2. NMR analysis of male fathead minnow urinary metabolites: A potential approach for studying impacts of chemical exposures

    Energy Technology Data Exchange (ETDEWEB)

    Ekman, D.R. [Ecosystems Research Division, U.S. EPA, 960 College Station Road, Athens, GA 30605 (United States)], E-mail: ekman.drew@epa.gov; Teng, Q. [Ecosystems Research Division, U.S. EPA, 960 College Station Road, Athens, GA 30605 (United States); Jensen, K.M.; Martinovic, D.; Villeneuve, D.L.; Ankley, G.T. [Mid-Continent Ecology Division, U.S. EPA, 6201 Congdon Boulevard, Duluth, MN 55804 (United States); Collette, T.W. [Ecosystems Research Division, U.S. EPA, 960 College Station Road, Athens, GA 30605 (United States)

    2007-11-30

    The potential for profiling metabolites in urine from male fathead minnows (Pimephales promelas) to assess chemical exposures was explored using nuclear magnetic resonance (NMR) spectroscopy. Both one-dimensional (1D) and two-dimensional (2D) NMR spectroscopy was used for the assignment of metabolites in urine from unexposed fish. Because fathead minnow urine is dilute, we lyophilized these samples prior to analysis. Furthermore, 1D {sup 1}H NMR spectra of unlyophilized urine from unexposed male fathead minnow and Sprague-Dawley rat were acquired to qualitatively compare rat and fish metabolite profiles and to provide an estimate of the total urinary metabolite pool concentration difference. As a small proof-of-concept study, lyophilized urine samples from male fathead minnows exposed to three different concentrations of the antiandrogen vinclozolin were analyzed by 1D {sup 1}H NMR to assess exposure-induced changes. Through a combination of principal components analysis (PCA) and measurements of {sup 1}H NMR peak intensities, several metabolites were identified as changing with statistical significance in response to exposure. Among those changes occurring in response to exposure to the highest concentration (450 {mu}g/L) of vinclozolin were large increases in taurine, lactate, acetate, and formate. These increases coincided with a marked decrease in hippurate, a combination potentially indicative of hepatotoxicity. The results of these investigations clearly demonstrate the potential utility of an NMR-based approach for assessing chemical exposures in male fathead minnow, using urine collected from individual fish.

  3. The Impact of Social Cognitive Theory and Rational Emotive Behavior Therapy Interventions on Beliefs, Emotions, and Performance of Teachers

    Science.gov (United States)

    Warren, Jeffrey Melvin

    2010-01-01

    Mental health continues to be a concern for individuals of all ages in the United States. Teachers and students are greatly affected by the impact of mental health related issues. Teachers perform in less than effective ways and student success is hindered when distress is experienced at school. Professional school counselors are in an excellent…

  4. The impact of flow injection on modem chemical analysis: has it fulfilled our expectations? And where are we going?

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    2004-01-01

    Presenting a condensation of the opening lecture of the 12th ICFIA conference, this communication presents a view of the impact that flow injection analysis (FIA) has had on modern analytical chemistry, evaluated both within the academic community and outside it, i.e., in “industry”. The ensuing...... developments of FIA, encompassing sequential injection analysis (SIA) and bead injection lab-on-valve (BI-LOV), are described and their individual features discussed. Finally some recent results of the activities from the author’s own research group are briefly mentioned....

  5. Line-imaging velocimetry for observing spatially heterogeneous mechanical and chemical responses in plastic bonded explosives during impact.

    Science.gov (United States)

    Bolme, C A; Ramos, K J

    2013-08-01

    A line-imaging velocity interferometer was implemented on a single-stage light gas gun to probe the spatial heterogeneity of mechanical response, chemical reaction, and initiation of detonation in explosives. The instrument is described in detail, and then data are presented on several shock-compressed materials to demonstrate the instrument performance on both homogeneous and heterogeneous samples. The noise floor of this diagnostic was determined to be 0.24 rad with a shot on elastically compressed sapphire. The diagnostic was then applied to two heterogeneous plastic bonded explosives: 3,3(')-diaminoazoxyfurazan (DAAF) and PBX 9501, where significant spatial velocity heterogeneity was observed during the build up to detonation. In PBX 9501, the velocity heterogeneity was consistent with the explosive grain size, however in DAAF, we observed heterogeneity on a much larger length scale than the grain size that was similar to the imaging resolution of the instrument. PMID:24007075

  6. Impact of anthracnose on the yield of soybean subjected to chemical control in the north region of Brazil

    Directory of Open Access Journals (Sweden)

    Moab Diany Dias

    2016-03-01

    Full Text Available ABSTRACT Losses due to soybean anthracnose, caused by Colletotrichum truncatum, have not been systematically quantified in the field, and the efficacy of chemical control of this disease is not known. This study shows an estimate of losses associated with the disease in soybean crops in the north of the country. Two trials with cv. M9144 RR were carried out in commercial fields in Tocantins State in the 2010/2011 and 2011/2012 growing seasons, in randomized blocks, with four replicates. Foliar applications were performed on plants at R1/R2 and R5.2 stages, employing CO2-pressurized equipment and application volume of 200 L ha-1. Nine fungicides and one untreated control were compared, and the disease gradients in the two seasons were obtained. The percentage of infected pods was calculated at the R6 stage. Grain yield ranged from 3,288 to 3,708 kg/ha in the untreated plots in 2010/2011 and 2011/2012, respectively, and from 3,282 to 4,110 kg/ha in the treated plots. In the 2010/2011 season, only azoxystrobin + cyproconazole significantly reduced the disease incidence, compared to untreated control plots, not differing from the remaining treatments. In the 2011/2012 season, there were no significant differences between treated and untreated plots. Highly significant correlations (p < 0.01 were found between yield and soybean anthracnose incidence on pods in both years (r = -0.85. For each 1% increment in the disease incidence, c. 90 kg/ha of soybean grain were lost. The current study determined that significant losses due to anthracnose occur in commercial crops in the north of the country and highlighted the limitation of chemical control as anthracnose management method.

  7. White popular (Populus alba L.) - Litter impact on chemical and biochemical parameters related to nitrogen cycle in contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Ciadamidaro, L.; Madejon, P.; Cabrera, F.; Madejon, E.

    2014-06-01

    Aim of study: The aim of this study was to determine the effect of litter from Populus alba on chemical and biochemical properties related to the N cycle in soils with different pH values and trace element contents. We hypothesized that this litter would influence several parameters related to the N cycle and consequently to soil health. Area of study: we collected two reforested contaminated soils of different pH values (AZ pH 7.23 and DO pH 2.66) and a non-contaminated soil (RHU pH 7.19). Materials and methods: Soil samples were placed in 2,000 cm{sup 3} microcosms and were incubated for 40 weeks in controlled conditions. Each soil was mixed with its corresponding litter, and soils without litter were also tested for comparison. Ammonium (NH{sub 4}{sup 4}+-N) and nitrate (NO{sub 3}{sup -} -N) content, potential nitrification rate (PNR), microbial biomass nitrogen (MBN), protease activity, and several chemical properties such as pH, available trace element concentrations (extracted with 0.01 M CaCl{sub 2}) were determined at different times of incubation. Main results: Values of available trace elements did not vary during the incubation and were always higher in acid soil. In neutral soils litter presence increased values of Kjeldahl-N, NO{sub 3} –-N content, potential nitrification rate (PNR), microbial biomass nitrogen (MBN) and protease activity. Presence of trace elements in neutral soils did not alter the parameters studied. However, acidic pH and high content of available trace elements strongly affected NH{sub 4}{sup +}-N and NO{sub 3}{sup -} -N, microbial biomass N and protease activity. Research highlights: Our results showed the negative effect of the acidity and trace element availability in parameters related with the N-cycle. (Author)

  8. Yeast Toxicogenomics: genome-wide responses to chemical stresses with impact in Environmental Health, Pharmacology and Biotechnology

    Directory of Open Access Journals (Sweden)

    Sandra Costa dos Santos

    2012-04-01

    Full Text Available The emerging transdisciplinary field of Toxicogenomics aims to study the cell response to a given toxicant at the genome, transcriptome, proteome and metabolome levels. This approach is expected to provide earlier and more sensitive biomarkers of toxicological responses and help in the delineation of regulatory risk assessment. The use of model organisms to gather such genomic information, through the exploitation of Omics and Bioinformatics approaches and tools, together with more focused molecular and cellular biology studies are rapidly increasing our understanding and providing an integrative view on how cells interact with their environment. The use of the model eukaryote Saccharomyces cerevisiae in the field of Toxicogenomics is discussed in this review. Despite the limitations intrinsic to the use of such a simple single cell experimental model, S. cerevisiae appears to be very useful as a first screening tool, limiting the use of animal models. Moreover, it is also one of the most interesting systems to obtain a truly global understanding of the toxicological response and resistance mechanisms, being in the frontline of systems biology research and developments. The impact of the knowledge gathered in the yeast model, through the use of Toxicogenomics approaches, is highlighted here by its use in prediction of toxicological outcomes of exposure to pesticides and pharmaceutical drugs, but also by its impact in biotechnology, namely in the development of more robust crops and in the improvement of yeast strains as cell factories.

  9. Systematic Review and Meta-analysis of the Impact of Chemical-Based Mollusciciding for Control of Schistosoma mansoni and S. haematobium Transmission.

    Directory of Open Access Journals (Sweden)

    Charles H King

    2015-12-01

    Full Text Available Programs for schistosomiasis control are advancing worldwide, with many benefits noted in terms of disease reduction. Yet risk of reinfection and recurrent disease remain, even in areas with high treatment coverage. In the search for means to better prevent new Schistosoma infections, attention has returned to an older strategy for transmission control, i.e., chemical mollusciciding, to suppress intermediate host snail species responsible for S. mansoni and S. haematobium transmission. The objective of this systematic review and meta-analysis was to summarize prior experience in molluscicide-based control of Bulinus and Biomphalaria spp. snails, and estimate its impact on local human Schistosoma infection.The review was registered at inception with PROSPERO (CRD42013006869. Studies were identified by online database searches and hand searches of private archives. Eligible studies included published or unpublished mollusciciding field trials performed before January 2014 involving host snails for S. mansoni or S. haematobium, with a primary focus on the use of niclosamide. Among 63 included papers, there was large variability in terms of molluscicide dosing, and treatment intervals varied from 3-52 weeks depending on location, water source, and type of application. Among 35 studies reporting on prevalence, random effects meta-analysis indicated that, on average, odds of infection were reduced 77% (OR 0.23, CI95% 0.17, 0.31 during the course of mollusciciding, with increased impact if combined with drug therapy, and progressively greater impact over time. In 17 studies reporting local incidence, risk of new infection was reduced 64% (RR 0.36 CI95% 0.25, 0.5, but additional drug treatment did not appear to influence incidence effects.While there are hurdles to implementing molluscicide control, its impact on local transmission is typically strong, albeit incomplete. Based on past experience, regular focal mollusciciding is likely to contribute

  10. DETERMINANTS OF THE VALUE OF SITE-SPECIFIC INFORMATION (SSI) IN AGRICULTURE: A UNIFYING THEORY TO ANALYZE ITS RELATIVE IMPACTS

    OpenAIRE

    Rejesus, Roderick M.; Nelson, Carl H.

    2000-01-01

    This paper develops a theoretically consistent behavioral model of farmer decision-making that allows for analysis of the relative impacts of the determinants of SSI value. The model departs from previous literature by assuming that SSI reduces uncertainty, but not eliminate it. Results show that increasing the accuracy (or the "level of informativeness") of SSI, increasing initial wealth, improving management ability to reduce uncertainty in the posterior, and increasing the uncertainty in t...

  11. Microbial decontamination by low dose gamma irradiation and its impact on the physico-chemical quality of peppermint (Mentha piperita)

    Energy Technology Data Exchange (ETDEWEB)

    Machhour, Hasna [Valorization of the Agro-Ressources and Food Chemistry, Department of Chemistry, Cadi Ayyad University, B.P. 2390, Marrakesh 40000 (Morocco); Laboratory of Biotechnology, Protection and Valorization of the Vegetable Resources, Cadi Ayyad University, B.P 2390, Marrakesh 40000 (Morocco); El Hadrami, Ismail [Laboratory of Biotechnology, Protection and Valorization of the Vegetable Resources, Cadi Ayyad University, B.P 2390, Marrakesh 40000 (Morocco); Imziln, Boujamaa [Laboratory of Biology and Biotechnology of Microorganisms, Environmental Microbiology and Toxicology Team ((mu)BioToxE, Department of Biology), Cadi Ayyad University, P.O. Box no. 2390, Marrakech 40000 (Morocco); Mouhib, Mohamed [Institut National de la Recherche Agronomique (INRA), Centre Regional de la Recherche Agronomique de Tanger, Unite de Recherche sur les Techniques Nucleaires, l' Environnement et la Qualite (URTNEQ), 78 Boulevard Sidi Mohamed Ben Abdellah, Tanger 90000 (Morocco); Mahrouz, Mostafa, E-mail: mahrouz10@yahoo.f [Valorization of the Agro-Ressources and Food Chemistry, Department of Chemistry, Cadi Ayyad University, B.P. 2390, Marrakesh 40000 (Morocco)

    2011-04-15

    Peppermint was inoculated with Escherichia coli and its decontamination was carried out by gamma irradiation at low irradiation doses (0.5, 1.0 and 2.66 kGy). The efficiency of this decontamination method was evaluated and its impact on the quality parameters of peppermint, such as the color and ash content, as well as the effect on fingerprint components such as phenols and essential oils, was studied. Gas chromatography coupled to mass spectrometry (GC/MS) and High Performance Liquid Chromatography (HPLC) were used to characterize essential oils and phenolic compounds, respectively. The results indicated a complete decontamination of peppermint after the low dose gamma irradiation without a significant loss in quality attributes.

  12. Microbial decontamination by low dose gamma irradiation and its impact on the physico-chemical quality of peppermint (Mentha piperita)

    Science.gov (United States)

    Machhour, Hasna; El Hadrami, Ismail; Imziln, Boujamaa; Mouhib, Mohamed; Mahrouz, Mostafa

    2011-04-01

    Peppermint was inoculated with Escherichia coli and its decontamination was carried out by gamma irradiation at low irradiation doses (0.5, 1.0 and 2.66 kGy). The efficiency of this decontamination method was evaluated and its impact on the quality parameters of peppermint, such as the color and ash content, as well as the effect on fingerprint components such as phenols and essential oils, was studied. Gas chromatography coupled to mass spectrometry (GC/MS) and High Performance Liquid Chromatography (HPLC) were used to characterize essential oils and phenolic compounds, respectively. The results indicated a complete decontamination of peppermint after the low dose gamma irradiation without a significant loss in quality attributes.

  13. Impact of temperature and storage duration on the chemical and odor quality of military packaged water in polyethylene terephthalate bottles

    International Nuclear Information System (INIS)

    The impact of temperature and storage time on military packaged water (MPW) quality was examined at four temperatures (23.0 °C to 60.0 °C) for 120 days. Polyethylene terephthalate (PET) bottles were filled in California and Afghanistan with unbuffered water treated by reverse osmosis. The US military's water pH long-term potability standard was exceeded, and US Food and Drug Administration (USFDA) and US Environmental Protection Agency (USEPA) drinking water pH and odor intensity limits were also exceeded. During a 70 day exposure period, Port Hueneme MPW total organic carbon and total trihalomethane levels increased from 37.7 °C, consume bottled water within 14 days of packaging

  14. Impact of mechanical, chemical and enzymatic pre-treatments on the methane yield from the anaerobic digestion of switchgrass

    International Nuclear Information System (INIS)

    The conversion of cellulosic crops into biofuels, including methane, is receiving a lot of attention lately. Panicum vergatum, or switchgrass, is a warm season perennial grass well adapted to grow in North America. Different pre-treatments were tested in 0.5 l batch reactors, at 35 °C, in order to enhance the methane production from switchgrass, including temperature, sonication, alkalinization and autoclaving. The methane production on the basis of volatile solids (VS) added to the fermentation were 112.4 ± 8.4, 132.5 ± 9.7 and 139.8 ml g−1 after 38 days of incubation for winter harvested switchgrass (WHS) after grinding, grinding with alkalinization, and grinding with alkalinization and autoclaving, respectively. The methane production was higher for fresh summer harvested switchgrass (SHS), with a production of 256.6 ± 8.2 ml g−1 VS after mulching, alkalinization and autoclaving. The methane production from SHS was improved by 29 and 42% when applying lignin (LiP) or manganese peroxidase (MnP), at 202.1 ± 9.8 and 222.9 ± 22.5 ml g−1 VS, respectively. The combination of an alkali pre-treatment with the MnP increased the methane production furthermore at 297.7 ml g−1 VS. The use of pectinases without chemical pre-treatment showed promising yields at 287.4 and 239.5 ml g−1 VS for pectate-lyase and poly-galacturonase, respectively. An estimation of the methane yield per hectare of crop harvested resulted in net energy production of 29.8, 49.7 and 78.1 GJ for winter harvested switchgrass, mulched and pretreated summer harvested switchgrass, respectively. Switchgrass represents an interesting candidate as a lignocellulosic crop for methane production. -- Highlights: ► Switchgrass is a model energy crops for biofuels production. ► This study evaluated different pre-treatments to enhance methane production. ► Pre-treatments increase significantly the methane produced from switchgrass. ► Enzymatic pre-treatments were superior to physical and

  15. Impact of chemical and structural anisotropy on the electrophoretic mobility of spherical soft multilayer particles: the case of bacteriophage MS2.

    Science.gov (United States)

    Langlet, Jérémie; Gaboriaud, Fabien; Gantzer, Christophe; Duval, Jérôme F L

    2008-04-15

    by the external proteic capsid but also by the chemical composition and hydrodynamic flow permeation of/within the inner RNA-protein bound layer and bulk RNA part of the bacteriophage. The impact of virus aggregation, as revealed by decreasing diffusion coefficients for decreasing pH values, is also discussed. PMID:18192368

  16. The impact of conventional and nuclear industries on the population A comparative study of the radioactive and chemical aspects

    CERN Document Server

    Coulon, R; Anguenot, F

    1988-01-01

    This study was carried out to make it possible to assess and localize in an objective manner the extent of the hazards and associated detrimental effects which are inherent in nuclear and non-nuclear industrial activities, among all the hazards to which the population of a given region is exposed. Rather than carry out a purely theoretical and speculative study a region was chosen as a basis to carry out a full- scale exercise, taking into account the existing real situation. The region chosen is situated in the south-east of France (Greater Rhone Delta) where almost all industrial activities can be found: electricity generating industries (thermal and nuclear power stations), the activities associated with them (extraction, processing, storage of waste, etc.) and industrial activities which are sources of pollution (refineries, chemical industries, etc.). To put the risks of all these activities (to workers, the public and the environment) in perspective, the case of other sources of risk, such as certain ag...

  17. Radiation thermo-chemical models of protoplanetary discs. III. Impact of inner rims on Spectral Energy Distributions

    CERN Document Server

    Thi, Wing-Fai; Kamp, Inga

    2010-01-01

    We study the hydrostatic density structure of the inner disc rim around HerbigAe stars using the thermo-chemical hydrostatic code ProDiMo. We compare the Spectral Energy Distributions (SEDs) and images from our hydrostatic disc models to that from prescribed density structure discs. The 2D continuum radiative transfer in ProDiMo includes isotropic scattering. The dust temperature is set by the condition of radiative equilibrium. In the thermal-decoupled case the gas temperature is governed by the balance between various heating and cooling processes. The gas and dust interact thermally via photoelectrons, radiatively, and via gas accommodation on grain surfaces. As a result, the gas is much hotter than in the thermo-coupled case, where the gas and dust temperatures are equal, reaching a few thousands K in the upper disc layers and making the inner rim higher. A physically motivated density drop at the inner radius ("soft-edge") results in rounded inner rims, which appear ring-like in near-infrared images. The...

  18. Analysis of copper-rich precipitates in silicon: chemical state,gettering, and impact on multicrystalline silicon solar cellmaterial

    Energy Technology Data Exchange (ETDEWEB)

    Buonassisi, Tonio; Marcus, Matthew A.; Istratov, Andrei A.; Heuer, Matthias; Ciszek, Theodore F.; Lai, Barry; Cai, Zhonghou; Weber,Eicke R.

    2004-11-08

    In this study, synchrotron-based x-ray absorption microspectroscopy (mu-XAS) is applied to identifying the chemical states of copper-rich clusters within a variety of silicon materials, including as-grown cast multicrystalline silicon solar cell material with high oxygen concentration and other silicon materials with varying degrees of oxygen concentration and copper contamination pathways. In all samples, copper silicide (Cu3Si) is the only phase of copper identified. It is noted from thermodynamic considerations that unlike certain metal species, copper tends to form a silicide and not an oxidized compound because of the strong silicon-oxygen bonding energy; consequently the likelihood of encountering an oxidized copper particle in silicon is small, in agreement with experimental data. In light of these results, the effectiveness of aluminum gettering for the removal of copper from bulk silicon is quantified via x-ray fluorescence microscopy (mu-XRF),and a segregation coefficient is determined from experimental data to beat least (1-2)'103. Additionally, mu-XAS data directly demonstrates that the segregation mechanism of Cu in Al is the higher solubility of Cu in the liquid phase. In light of these results, possible limitations for the complete removal of Cu from bulk mc-Si are discussed.

  19. Pathway of FeEDTA transformation and its impact on performance of NOx removal in a chemical absorption-biological reduction integrated process.

    Science.gov (United States)

    Li, Wei; Zhao, Jingkai; Zhang, Lei; Xia, Yinfeng; Liu, Nan; Li, Sujing; Zhang, Shihan

    2016-01-01

    A novel chemical absorption-biological reduction (CABR) integrated process, employing ferrous ethylenediaminetetraacetate (Fe(II)EDTA) as a solvent, is deemed as a potential option for NOx removal from the flue gas. Previous work showed that the Fe(II)EDTA concentration was critical for the NOx removal in the CABR process. In this work, the pathway of FeEDTA (Fe(III)/Fe(II)-EDTA) transformation was investigated to assess its impact on the NOx removal in a biofilter. Experimental results revealed that the FeEDTA transformation involved iron precipitation and EDTA degradation. X-ray photoelectron spectroscopy analysis confirmed the iron was precipitated in the form of Fe(OH)3. The iron mass balance analysis showed 44.2% of the added iron was precipitated. The EDTA degradation facilitated the iron precipitation. Besides chemical oxidation, EDTA biodegradation occurred in the biofilter. The addition of extra EDTA helped recover the iron from the precipitation. The transformation of FeEDTA did not retard the NO removal. In addition, EDTA rather than the iron concentration determined the NO removal efficiency.

  20. Spatial extent of band bending in diamond due to ion impact as measured by secondary electron emission: Experiment and theory

    International Nuclear Information System (INIS)

    Although hydrogentated diamond emits exceptionally high numbers of electrons upon single ion impact, the secondary electron yield decays at an extremely rapid rate as a function of ion fluence. We report measurements of this rapid decay at extremely low fluences where the ion tracks are widely separated and explain the results by a model based on the downwards bending of the conduction band edge, due to positive charge trapped within the ion track. The present work demonstrates the importance of charge trapping in explaining the electronic properties of diamond and other wide band gap materials