Search

Enantio-selective molecular dynamics of (±)- o,p -DDT uptake and degradation in water-sediment system is described. Both uptake and degradation processes of (-)- o,p -DDT were slightly higher than (+)- o,p -DDT enantiomer. The optimized parameters for uptake were 7.0 μg L −1 concentration of o,p -DDT, 60 min contact time, 5.0 pH, 6.0 g L −1 amount of reverine sediment and 25 °C temperature. The maximum degradation of both (-)- and (+)- o,p -DDT was obtained with 16 days, 0.4 μg L −1 concentration of o,p -DDT, pH 7 and 35 °C temperature. Both uptake and degraded process followed first order rate reaction. Thermodynamic parameters indicated exothermic nature of uptake and degradation processes. Both uptake and degradation were slightly higher for (-)-enantiomer in comparison to (+)-enantiomer of o,p -DDT. It was concluded that both uptake and degradation processes are responsible for the removal of o,p -DDT from nature but uptake plays a crucial role. The percentage degradations of (-)- and (+)- o,p -DDT were 30.1 and 29.5, respectively. This study may be useful to manage o,p -DDT contamination of our earth's ecosystem. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plasma-chemical conversion of hydrogen sulfide in the atmosphere of methane with addition of CO and O in the nonequilibrium plasma of barrier discharge is studied. The degree of hydrogen sulfide removal reaches 97 vol%. The degree of methane transformation does not exceed 14 vol%. Gaseous reaction products contain hydrogen, carbon oxides, and C-C hydrocarbons. The energy consumption for the removal of hydrogen sulfide ranges from 84 to 182 eV molecule. The process is accompanied by the formation of deposits on the surface of reactor electrodes. The composition of deposits is studied. Organic linear and cyclic polysulfides, as well as sulfones of various structures are identified in soluble components of deposits. Based on the experimental data and the results of theoretical estimates, a radical chain reaction mechanism is proposed. It is shown that the formation of polysulfide compounds with terminal alkyl and oxygen-containing groups is provided by the reactions between atomic oxygen, SH, and alkyl radical which were formed in the initial stages of processes in the non-equilibrium plasma of barrier discharge. [ABSTRACT FROM AUTHOR]

We have presented a density functional theory study of the adsorption properties of NO and O molecules on heterostructured TiO/ZnO nanocomposites. The most stable adsorption configurations, adsorption energies and charge transfers were calculated. The electronic properties of the complex TiO/ZnO heterostructures were described using the density of states and molecular orbital analyses. For NO adsorption, it was found that the oxygen atoms preferentially move towards the fivefold coordinated titanium atoms, whereas the nitrogen atom binds to the zinc atom. In the case of O adsorption, the side oxygen atoms bind to the fivefold coordinated titanium sites, and the central oxygen atom does not contribute to the adsorption any longer. Thus, the interaction of NO and O molecules with TiO side of nanocomposite is strongly favored. On the N-doped TiO/ZnO nanocomposites, the adsorption process is more energetically favorable than that on the pristine ones. The N-doped nanocomposites are far more sensitive to gas detection than the undoped ones. In TiO/ZnO nanocomposites, the interactions of gas molecule and TiO are stronger than those between gas molecule and bare TiO nanoparticles, which reveals that ZnO is conducive to the interaction of NO and O molecules with TiO nanoparticles. Our theoretical results suggest multicomponent TiO/ZnO nanocomposite as a potential material for gas sensing application. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Density functional theory calculations were carried out to investigate the adsorption behaviors of O molecules on the undoped and N-doped TiO/MoS nanocomposites. With the inclusion of vdW interactions, which correctly account the long-range dispersion energy, the adsorption energies and final geometries of O molecules on the nanocomposite surfaces were improved. For O molecules on the considered nanocomposites, the binding sites were located on the fivefold coordinated titanium atoms of the TiO anatase. The structural properties of the adsorption systems were examined in view of the bond lengths and bond angles. The variation of electronic structures was also discussed in view of the density of states, molecular orbitals and distribution of spin densities. The results suggest that the adsorption of the O molecule on the N-doped TiO/MoS nanocomposite is more favorable in energy than that on the pristine one, indicating that the N-doped nanocomposite has higher sensing capability than the pristine one. This implies that the N-doped TiO/MoS nanocomposite would be an ideal O gas sensor. However, our calculations thus provide a theoretical basis for the potential applications of TiO/MoS nanocomposites as efficient O sensors, leading to very interesting results in the context of air quality measurement. [ABSTRACT FROM AUTHOR]

Unsaturated absorption coefficients are measured using a tunable CO laser in pure CO and CO:O = 1:2 and CO:N = 1:2 gas mixtures at the central frequencies of the R(8), R(22), P(8), P(22), and P(36) CO 100-001 transition lines under a pressure of 100 Torr in the temperature range 300-700 K. The collisional broadening coefficients of the CO spectral lines by O and N are obtained. The temperature dependences of these coefficients are approximated by power functions with two different exponents. [ABSTRACT FROM AUTHOR]

The present article has as its aim to analyse some issues that came about during the translation of Ó, by Nuno Ramos. From the practical analysis of translation choices, we intend to approach the theoretical issues that influenced each practical choice. Formal translation issues relating to rhythm and figures of sound will also be discussed, due to the fact that Nunos Ramos's prose can be considered as poetic prose. [ABSTRACT FROM AUTHOR]

The binding of ozone molecule to the B bowl-shaped structure is scrutinized using the density functional theory (DFT) calculations. The interactions are investigated using B3LYP, B3LYP-D3, WB97XD, M06-2X and TPPSH methods. The ozone binding to the B structure is studied in terms of energetical, structural and electronic features. The results indicate that although ozone molecule weakly interacts with concave side of structure, it adds to the convex side and the edge of B structure. The ozone binding to the edge of B is more efficient than its convex side. The HOMO-LUMO gaps of the stable systems are reduced with respect to pure B sheet. This could be applied as a chemical signal. The obtained results introduce the B structure as an efficient ozone adsorbent. [ABSTRACT FROM AUTHOR]

Multiple occurrences of bedded barite (BaSO 4 ) are preserved in mudstones of the upper-most Canol Formation (Frasnian) of the Selwyn Basin (Canada). Samples of barite were collected from eight sites (seven measured sections), and examined using petrographic and isotopic techniques ( 87 Sr/ 86 Sr, δ 34 S and δ 18 O values) to determine whether the barite has a diagenetic or hydrothermal origin. Barite at all locations occurs in two morphologies: (1) laminated barite composed of thin layers of microcrystalline barite with lesser amounts of pyrite and hyalophane (Ba-K-feldspar) interlaminated with mudstone, and (2) nodular barite consisting of barite, hyalophane, cymrite (hydrous Ba-silicate) and minor pyrite. At the Cowan occurrence, one sample has a mineral assemblage comprising barite and nodular barium carbonates (witherite, norsethite). The δ 34 S and δ 18 O values of the laminated barite co-vary, and range between +24.1 and +35.3‰ and +14.8 to +18.3‰ respectively, with the exception of one sample with δ 34 S and δ 18 O values of +32.9‰ and −0.5‰. The laminated samples have an average 87 Sr/ 86 Sr of 0.7085 (n = 8), which is consistent with Frasnian seawater (0.7081) that has undergone some minor water sediment interaction during early diagenesis. The nodular barite has highly variable δ 34 S (+4.8 to +56.5‰) and δ 18 O (+9.2 to +19.3‰) values, which developed from more evolved diagenetic pore fluids with limited sulphate re-supply (i.e., as a relatively closed system). In these conditions sulphate reduction likely occurred at a slower rate, and the sulphate in the barite records both kinetic (δ 34 S SO4 ) and equilibrium (δ 18 O SO4 ) isotope effects. One sample of nodular barite has a 87 Sr/ 86 Sr ratio of 0.7086. The single sample with a barite and barium-carbonate assemblage at Cowan has a 87 Sr/ 86 Sr ratio of 0.7133, a δ 34 S value of +23.9‰, and a δ 18 O value of +10.7‰ and may represent a local hydrothermal event at this site. Our data supports the interpretation that the barite horizon is a stratigraphic marker throughout the Canol Formation. Laminated and nodular barite formed as a result of diagenetic processes, which recycled Ba from organic matter in the sediment below, and reprecipitated it above, the sulphate methane transition zone in the sediments. The results of this study are similar to those obtained for other Late Devonian sediment-hosted barite occurrences in North America (Yukon, Nevada, New York State), meaning these occurrences likely formed by similar processes and diagenetic pore water conditions within oceanic sediments that covered the North American continent during the Late Devonian. We suggest that the combination of high biological productivity and low seawater sulphate at this time contributed to the efficient cycling of Ba from seawater into the sediments on the continental margin. [ABSTRACT FROM AUTHOR]

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A combination of δ O and salinity data was employed to explore the freshwater balance in the Canada Basin in summer 2008. The Arctic river water and Pacific river water were quantitatively distinguished by using different saline end-members. The fractions of total river water, including the Arctic and Pacific river water, were high in the upper 50 m and decreased with depth as well as increasing latitude. In contrast, the fraction of Pacific river water increased gradually with depth but decreased toward north. The inventory of total river water in the Canada Basin was higher than other arctic seas, indicating that Canada Basin was a main storage region for river water in the Arctic Ocean. The fraction of Arctic river water was higher than Pacific river water in the upper 50 m while the opposite was true below 50 m. As a result, the inventories of Pacific river water were higher than those of Arctic river water, demonstrating that the Pacific inflow through the Bering Strait is the main source of freshwater in the Canada Basin. Both the river water and sea-ice melted water in the permanent ice zone were more abundant than those in the region with sea-ice just melted. The fractions of total river water, Arctic river water, Pacific river water increased northward to the north of 82°N, indicating an additional source of river water in the permanent ice zone of the northern Canada Basin. A possible reason for the extra river water in the permanent ice zone is the lateral advection of shelf waters by the Trans-Polar Drift. The penetration depth of sea-ice melted waters was less than 30 m in the southern Canada Basin, while it extended to 125 m in the northern Canada Basin. The inventory of seaice melted water suggested that sea-ice melted waters were also accumulated in the permanent ice zone, attributing to the trap of earlier melted waters in the permanent ice zone via the Beaufort Gyre. [ABSTRACT FROM AUTHOR]

Copyright of Revista del Museo de Antropología is the property of Museo de Antropologia - IDACOR and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Studies of the effects of specific policy measures for innovation have focused mainly on actions based on direct R&D support. However, the innovation studies literature sees innovation as an interactive process, emphasising the role of knowledge exchange for successful innovation. Furthermore, it is increasingly accepted that co-location is not sufficient for knowledge exchange to occur. Consequently, there is also a need to assess the effectiveness of policy measures to promote knowledge exchange between co-located actors. The objective of this paper is to narrow this gap by exploring the outcome of an indirect policy in stimulating coordination and networking. The paper analyses policies for increased networking in a mechatronics district located in the peripheral and less innovative region Apulia (Southern Italy). The success of the coordination and networking action is examined by adopting a longitudinal approach. In order to assess the association of the policy with the overall network structure, social network analysis is used to analyse the data. We compare characteristics of the network in the early and later phase of the district across five dimensions of knowledge exchange, identifying a large increase in the use of partnerships as the main effect of the policy. [ABSTRACT FROM AUTHOR]

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Procedures are proposed for the naming of individual atoms, P, O, F, N, and S in phosphate esters, amidates, thiophosphates, polyphosphates, their mimics, and analogues of transition states for enzymecatalyzed phosphoryl transfer reactions. Their purpose is to enable scientists in very different fields, e.g. biochemistry, biophysics, chemistry, computational chemistry, crystallography, and molecular biology, to share standard protocols for the labelling of individual atoms in complex molecules. This will facilitate clear and unambiguous descriptions of structural results, as well as scientific intercommunication concerning them. At the present time, perusal of the Protein Data Bank (PDB) and other sources shows that there is a limited degree of commonality in nomenclature, but a large measure of irregularity in more complex structures. The recommendations described here adhere to established practice as closely as possible, in particular to IUPAC and IUBMB recommendations and to "best practice" in the PDB, especially to its atom labelling of amino acids, and particularly to Cahn-Ingold-Prelog rules for stereochemical nomenclature. They are designed to work in complex enzyme sites for binding phosphates but also to have utility for non-enzymatic systems. Above all, the recommendations are designed to be easy to comprehend and user-friendly. [ABSTRACT FROM AUTHOR]

The aging process appears to be a precursor to many age-related diseases, perhaps the most impactful of which is cardiovascular disease (CVD). Heart disease, a manifestation of CVD, is the leading cause of death in the USA, and heart failure (HF), a syndrome that develops as a consequence of heart disease, now affects almost six million American. Importantly, as this is an age-related disease, this number is likely to grow along with the ever-increasing elderly population. Hallmarks of the aging process and HF patients with a reduced ejection fraction (HFrEF) include exercise intolerance, premature fatigue, and limited oxygen delivery and utilization, perhaps as a consequence of diminished peripheral vascular function. Free radicals and oxidative stress have been implicated in this peripheral vascular dysfunction, as a redox imbalance may directly impact the function of the vascular endothelium. This review aims to bring together studies that have examined the impact of oxidative stress on peripheral vascular function and oxygen delivery and utilization with both healthy aging and HFrEF. [ABSTRACT FROM AUTHOR]

We report densities and surface reaction probabilities of O and N atoms during sputter deposition of ZnInON films on ZnO templates, measured via vacuum ultraviolet absorption spectroscopy. O density is almost constant of 4.5 \times 10^11 cm−3 irrespective of O2 gas flow rate, whereas N density increases sharply from 2.7 \times 10^11 cm−3 for O2 gas sccm to 7.7 \times 10^11 cm−3 for 0.6 sccm and it increases gradually 10^11 cm−3 for 5 sccm. The surface reaction probability \beta O of O atoms on ZnInON increases significantly from 0.022 to 0.404 with increasing O2 gas flow rate from 0 to 5 sccm, whereas \beta N of N atoms on ZnInON decreases slightly from 0.018 to 0.006. The stoichiometric chemical compositional ratio of ZnInON films with [Zn]/([Zn] + [In]) = [O]/([O] + [N]) = 94% is obtained at \beta O=0.404 of O atoms. This stoichiometric compositional ZnInON films grow coherently on ZnO templates, while nonstoichiometric films do not. The stoichiometric chemical composition is the key to coherent growth of ZnInON films. [ABSTRACT FROM PUBLISHER]

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This research strives to investigate mobile learning among applicants of university entrance exam and also with motivation presenting a new framework for acceptance of mobile learning. In this study، definitions of mobile teaching، models used in this research (innovation diffusion theory models، Debone& McLean’s model، technology acceptance model and Dahlberg-Öörni fusion model ). The participants in this study are three schools that have 190 volunteers for entrance to college. The instrument used، was a questionnaire، and in order to examine the reliability of the questionnaire، Cranach’s Alpha and for investigating the relations between variables Pearson correlation and simple regression has been used. The study found that the research framework is confirmed with skilled mobile phone use، perceived ease of use، perceived usefulness، user satisfaction، and acceptance of mobile learning.

An introduction is presented in which the editor discusses articles in the issue on topics including research on the effect of motivating operations; understanding of how operants work; and the complete theory of behavior without understanding motivation.

This article proposes an analysis of the representation of the city in João Antônio’s literature, having as main reference the book Ô, Copacabana!, published in 1978. The city in João Antônio’s writings seems to be composed by the particular language and focus of the narrator, who wants himself identified to the lower classes, emulating the talk of the excluded people by a linguistic treatment, with its syntactic, rhythmic and vocabulary implications, building a point of view apart from the representations of the upper classes. Thus, João Antônio tries to represent the city through the focus of those social classes, which results in the preference for unknown places, marginal from official images.

The purpose of the paper is to investigate three issues. First, the paper tries to understand the definition of competition and hence the type of competition policy that can be drawn from the modern so-called Neo-Schumpeterian literature. We will see that this literature is abundant and diversified. In spite of its variety, it has also common features regarding the theory of competition as well as competition policy. Secondly we will also emphasize the various aspects of Schumpeter's legacy that were or are under-estimated by his contemporary followers concerning the concept of competition. We will argue that these aspects are not negligible and that they may also influence the impact of Schumpeter's own contribution to the characterization but also the criticism of present developments that claim to build a conception of competition policy in line with Schumpeter's original message. Finally, and more generally, we will stress how Schumpeter's and Neo-Schumpeterian developments and preoccupations in the field of competition can help us to enlighten the present developments related to competition and industrial policies and to set up their limits. [ABSTRACT FROM AUTHOR]

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Positron emission tomography (PET) enables quantitative measurements of various biological functions. Accuracy in data acquisition and processing schemes is a prerequisite for this. The correction of scatter is especially important when a 3D PET scanner is used. The aim of this study was to validate the use of a simplified calculation-based scatter correction method for 15O studies in the brain. Methods: We applied two scatter correction methods to the same 15O PET data acquired from patients with cerebrovascular disease (n = 10): a hybrid dual-energy-window scatter correction (reference method), and a deconvolution scatter correction (simplified method). The PET study included three sequential scans for 15O-CO, 15O-O2, and 15O-H2O, from which the following quantitative parameters were calculated, cerebral blood flow, cerebral blood volume, cerebral metabolic rate of oxygen, and oxygen extraction fraction. Results: Both scatter correction methods provided similar reconstruction images with almost identical image noise, although there were slightly greater differences in white-matter regions compared with gray matter regions. These differences were also greater for 15O-CO than for 15O-H2O and 15O-O2. Region of interest analysis of the quantitative parameters demonstrated that the differences were less than 10 % (except for cerebral blood volume in white-matter regions), and the agreement between the methods was excellent, with intraclass correlation coefficients above 0.95 for all the parameters. Conclusions: The deconvolution scatter correction despite its simplified implementation provided similar results to the hybrid dual-energy-window scatter correction. We consider it suitable for application in a clinical 15O brain study using a 3D PET scanner. [ABSTRACT FROM AUTHOR]

An operationally simple, and cost efficient conversion of carboxylic acids into hydroxamic acid derivatives via a high-energy mechanochemical activation is presented. This ball milling methodology was applied to a wide variety of carboxylic acids dramatically improving purification issues associated with this class of molecules, which still remain one of the main bottlenecks of classical methodologies. [ABSTRACT FROM AUTHOR]

There is a growing interest to identify and quantify the benefits provided by the presence of trees in urban environment in order to improve the environmental quality in cities. However, the evaluation and estimate of plant efficiency in removing atmospheric pollutants is rather complicated, because of the high number of factors involved and the difficulty of estimating the effect of the interactions between the different components. In this study, the EMEP MSC-W model was implemented to scale-down to tree-level and allows its application to an industrial-urban green area in Northern Italy. Moreover, the annual outputs were compared with the outputs of UFORE (nowadays i- Tree), a leading model for urban forest applications. Although, EMEP/MSC-W model and UFORE are semi-empirical models designed for different applications, the comparison, based on O, NO and PM removal, showed a good agreement in the estimates and highlights how the down-scaling methodology presented in this study may have significant opportunities for further developments. [ABSTRACT FROM AUTHOR]

Copyright of AStA Wirtschafts- und Sozialstatistisches Archiv is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Cr resonance frequency in ammonium dichromate has been detected at 4202 kHz giving a Qcc of 8404 kHz (assuming η= 0). Calculations suggest that the value of the Cr quadrupole moment is about 84 mB lower that the currently accepted value. The resonance frequencies of two O nuclei have also been detected giving Qcc = 2800, 2890 kHz and η = 0.726, 0.780 respectively. The value for coupling and asymmetry parameter for N has been refined using zero field NQR giving a value Qcc = 78.8 kHz and η= 0.645 the asymmetry value being considerably lower than the value previous reported. [ABSTRACT FROM AUTHOR]