bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of hexagonal ferrites BaFe12‐2xZnxTixO19 (0 ≤ x ≤ 2) by thermal decomposition of freeze‐dried precursors
Authors: Rösler S. , Wartewig P. , Langbein H.
Published: October 2003

Substituted barium hexaferrites, BaFe12‐2xZnxTixO19 (0 ≤ x ≤ 2), have been synthesized by thermal decomposition of freeze‐dried acetate precursors. Decomposition and phase formation were investigated by means of thermal analysis, XRD and IR spectroscopy. The initially amorphous decomposed precursor reacts to the substituted hexaferrite via a spinel‐like maghemite (γ‐Fe2O3) and Zn/Ti containing spinel ferrites. The synthesis method allows a decrease of the reaction temperature and time, necessary for producing a single phase hexaferrite. At relative low reaction temperatures, the substitution rate x shows remarkable differences at different iron sublattices. For x ≤ 0,8 this selective substitution results in an increase of magnetization as x grows. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study on rapid growth of highly‐deuterated DKDP crystals
Authors: Wang S. L. , Gao Z. S. , Fu Y. J. , Duan A. D. , Sun X. , Fang C. S. , Wang X. Q.
Published: October 2003

Highly‐deuterated potassium dihydrogen phosphate (DKDP) crystals were grown rapidly from point seeds under high supersaturation in a temperature range of 40‐60 °C. The growth rate was about 1‐2 order of magnitude higher than that of the traditional temperature reduction method. It was found that highly pure raw materials, overheating at high temperature, ultrafine filtration and supersaturation stability were needed to keep the solution from spontaneous nucleation at high overcooling. The effect of growth conditions on pyramid faces was different from that of prismatic faces. The tetragonal to monoclinic phase solubility transition scarcely occurred in our experiments even though the overcooling of monoclinic phase was as high as 10 °C in some cases. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, X‐ray data, and Hall effect measurements of Li‐doped Tl‐Ba‐Ca‐Cu‐O superconductor
Authors: Kayed T. S.
Published: October 2003

Lithium‐doped Tl‐based superconductor was prepared by adding an amount of 0.3 mol.% to the Tl1.8Ba2Ca2.2Cu3Ox compound. The usual solid‐state reaction method has been applied under optimum conditions. The x‐ray data of the sample show a tetragonal structure with a high ratio of Tl‐2223 superconducting phase. The sample showed a transition at 125 K and the zero resistance was observed at 117 K. Longitudinal (transport) and transverse (Hall) resistivities were measured at different temperatures under different magnetic fields and the data were interpreted. A positive Hall coefficient was observed at normal state and a sign reversal appears at temperatures lower than the critical temperature. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Triple axis diffractometric investigations of the microstructure of thin AlxGa1‐xN epitaxial films
Authors: Zielinska‐Rohozinska E. , Kowalska M. , Pakuła K.
Published: October 2003

AlxGa1‐xN/GaN (Si doped or undoped) with the Al content in the composition range of 0.046 ≤ x ≤ 0.164 grown on the c sapphire face by atmospheric pressure MOCVD method were studied by high resolution x‐ray diffraction including symmetrical and asymmetrical ω/2θ scans and reciprocal space maps. A high sensitivity to small inhomogeneities of the layer thickness and lattice mismatch between AlGaN and GaN is reported, recognised as changes in the interference pattern of the diffraction peak observed across the sample. They are very well correlated with optical properties derived from independent photoreflectivity measurements. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Changes of Auger parameter in doped SnO2 powders
Authors: Dobler D. , Oswald S. , Behr G. , Werner J. , Wetzig K.
Published: October 2003

Doped SnO2 powders were studied using X‐ray photoelectron spectroscopy (XPS). The Auger parameters (AP) for Sn and different doping elements were determined. A dependence of the Auger parameter on the doping element and doping concentration was observed. The detected shift could be correlated with the electrical properties of the studied samples as well as with the formation of a second phase and a segregation layer at the surface. Bulk doping with elements having a valency greater than 4 (Sb), leads to an increase of the electron density connected with a decrease of resistivity. In this case we can observe the shift of the AP to higher values. This means that the relaxation of the electron holes is energetically more favourable for Sb doped than for pure tin oxide. On the other side, doping with elements the valency of which is less than 4 (In) on tin sites leads to a decrease in electron density and causes an increase of resistivity of the material. We observe in this case a shift of the AP to lower values due to lower relaxation energy. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Poole‐Frenkel electrical conduction in europium oxide films deposited on Si(100)
Authors: Dakhel A. A.
Published: October 2003

Thin Eu2O3 films were prepared on Si (P) substrates to form MOS devices. The oxide crystal structure was determined by X‐ray diffraction (XRD). The electrical transport properties of the devices with amorphous and crystalline Eu oxide were investigated. The current‐voltage and current‐temperature characteristics suggest a Poole‐Frenkel (PF) type mechanism of carrier transport through the device when the applied field is more than 105 V/cm. A deviation from PF leakage current course was found and attributed to the current carrier trapping. We have also observed that, the dielectric spectra of MOS structure are different when the insulator is an amorphous or crystalline thin film. From which we calculate the relaxation time (τ) of the interface (insulator/semiconductor) dipoles. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical characterization of thermally evaporated thin CdO films
Authors: Dakhel A. A. , Henari F. Z.
Published: October 2003

Cadmium Oxide films have been prepared by vacuum evaporation method on a glass substrate at room temperature. Detailed structural, optical, and electrical properties of the films are presented at different annealing temperatures. The crystal structure of the samples was studied by X‐ ray diffraction. The spectral absorption coefficient of the CdO film at the fundamental absorption region (450‐650nm) was determined using the spectral data of transmittance. The direct and indirect band gap energies were determined and found to be 2.33 eV and 1.95 eV respectively. The third order optical nonlinearities χ(3) of CdO films has been measured used the z‐can technique. The real and imaginary parts of χ(3) have been measured at 514 nm and found to be 1.7x10‐3 esu and 3.0x10‐3 esu, respectively. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical and microhardness studies of semiorganic nonlinear optical material: L‐ histidine tetrafluoroborate
Authors: Ramajothui Jayaraman , Dhanuskodi Sivasubramanian
Published: October 2003

L‐histidine tetrafluoroborate (L‐HFB) a semiorganic nonlinear optical material has been synthesized in aqueous solution at 50°C and characterized by FT‐IR and FT‐Raman spectroscopy studies. The solubility was determined in different solvents such as water, methanol and water mixture of methanol. The single crystals with dimensions 15x12x3 mm3 were grown by slow evaporation method within four weeks with approximate growth rate of 0.25 mm/day. The grown crystals have been subjected to single crystal X‐ray diffraction studies to determine the unit cell dimensions and morphology. The Kurtz powder second harmonic generation test shows that the compound is a potential candidate for frequency conversion. The refractive index has been measured using He‐Ne laser. The microhardness test was carried out and the load dependence hardness was observed. The material has a wide transparency in the entire visible region. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, crystal and molecular structure of trans‐bis(2‐pyridinepropanol)bis(saccharinato)nickel(II)
Authors: Yilmaz V. T. , Hamamci S. , Thöne C.
Published: October 2003

Trans‐bis(2‐pyridinepropanol)bis(saccharinato)nickel(II), [Ni(sac)2(pypr)2], where sac and pypr are the saccharinate anion and the 2‐pyridinepropanol molecule, respectively, crystallizes in the triclinic space group P$\bar 1$ (No. 2) with a = 8.1981(8), b = 9.9680(10), c = 10.4956(10) Å, α = 90.740(3)° β = 108.142(3)°, γ = 111.025(3)°, Z = 1, V = 1.537 Å3. The structure of the nickel(II) complex consists of neutral molecules in which the nickel(II) ion sits on a center of symmetry and is octahedrally coordinated by two sac ligands, and two neutral pypr ligands. The pypr acts as a bidentate N‐ and O‐donor ligand forming a seven‐membered chelate ring, while sac behaves as a monodentate O‐donor ligand via the carbonyl O atom. The Ni‐N bond distance is 2.1016(15) Å, whereas the Ni‐Opypr and Ni‐Osac bond distances are 2.1280(12) and 2.0792(11) Å, respectively. The individual molecules are held together with a strong hydrogen bond between the hydroxyl O atom of pypr and N atom of sac and the C‐H…O type weak hydrogen bonds between some ring hydrogen atoms of pypr and sac, and the carbonyl and sulfonyl O atoms of sac in the neighbouring molecules. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal structure, thermal analysis and IR spectroscopy investigations of N, N‐dimethyl‐1,3‐propanediammonium monohydrogenmonophosphate trihydrate
Authors: Chtioui A. , Jouini A.
Published: October 2003

A new organic monohydrogenmonophosphate (C5H16N2)HPO4.3H2O (abbreviate as MPAP) is prepared by reacting H3PO4 with N, N‐dimethyl‐1,3‐propanediamine. This compound crystallizes in the orthorhombic crystal system, space group Pca21. Unit cell parameters are a % 8.1445(1) Å, b % 11.7734(2) Å, c % 12.9021(2) Å, with, Z % 4 and ρm % 1.31 g cm−3. The structure was solved, using the direct methods and refined against F2 to a reliability R factor of 0.0257. Three types of hydrogen bonds participate to the structural cohesion: O(P)—H…O, O(W)—H…O and N—H…O. The first one connects HPO4 groups in infinite chains. This organization of the phosphoric groups creates voids in which are located the water molecules which are themselves connected by the second type of hydrogen bonds to the adjacent phosphoric groups that lead to a typical layer organization of a polyanion [HPO4.(H2O)3 ]2n−n. The third hydrogen bond type is responsible for the cohesion between the two‐dimensional polyanions. Thus, a framework in a threedimensional way is then created. The thermal decomposition of MPAP shows a large endothermic effect corresponding to the elimination of the water molecules and a set of endotherms which are probably due to the evolution of ammonia from the structure and the decomposition. The title compound was also characterized by IR spectroscopy, the interpretation of the spectra is based on theoretical analyses and literature data. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐assembly synthesis and structure of mono‐ and di‐nuclear uranyl complex
Authors: Lu Sheming , Ke Yanxiong , Li Jianmin , Zhou Shuxi , Wu Xintao , Du Wenxin
Published: October 2003

Mixing the malonate (mal), 4,4′‐bipyridine, UO2(CH3COO)2 · 2H2O in different solvent condition gets two compounds (bpy)2(H2bpy)[UO2(mal)2(μ‐H2O)] · 8H2O (1) and (H2bpy)[UO2(mal)2] · 2H2O (2). Both complexes contain seven‐coordinated pentagonal bipyramidal uranium center. Crystal 1 is mononuclear structure and crystal 2 contains dinuclear [(UO2)2(mal)2(μ2‐mal)2]4‐ subunit. Particularly, Crystal 2 forms the twodimensional supramolecular topology by hydrogen bonds. The sheet constructs from two sorts of chamber, of which the larger one has two water molecular guests. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The salt of l‐prolinium picrate
Authors: Min Jin Zhi , Jiang Pan Yuan , Lin Hu Mao , Shen Liang , Chao Li Mei
Published: October 2003

A crystalline salt of prolinium picrate, C11H12N4O9, has been prepared and characterized by X‐ray crystallography. The salt crystallizes in orthorhombic space group P212121 with a = 6.325(1)Å, b = 9.269(1)Å, c = 24.379(4)Å, V = 1429.4(5)Å3, Z = 4. In the title salt, the picrate and prolinium ion are held by different bifurcated hydrogen bonds of N‐H—O type, and stablized by bifurcated hydrogen bonds of CH—O type. There exists a competion between hydrogen bonds and π–π stacking in determining the title crystal. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Bifunctional Electrocatalyst Containing Tris(2,2′‐bipyridine) Ruthenium(II) and 12‐Molybdophosphate Bulk‐Modified Carbon Paste Electrode
Authors: Wang Xiu‐Li , Han Zheng‐Bo , Wang En‐Bo , Zhang Hong , Hu Chang‐Wen
Published: October 2003

The electroactive composite containing tris(2,2′‐bipyridine) ruthenium(II) and 12‐molybdophosphate (RuPMo12) was synthesized and first used as a bifunctional electrocatalyst to fabricate a chemically bulk‐modified carbon paste electrode (RuPMo12‐CPE) by direct mixing. The electrochemical behavior of the RuPMo12‐CPE was studied by cyclic voltammetry. The RuPMo12‐CPE presents good electrocatalytic activity not only toward the reduction of hydrogen peroxide and bromate, which is attributed to the function of molybdophosphate, but also toward the oxidation of arsenite, which is primarily attributed to the function of tris(2,2′‐bipyridine) ruthenium(II). The remarkable advantage of the RuPMo12‐CPE is its good stability owing to the insolubility of RuPMo12 and reproducibility of surface renewal.
Ni(II)cyclam Catalyzed Reduction of CO2 – Towards a Voltammetric Sensor for the Gas Phase
Authors: Jacquinot P. , Hauser P. C.
Published: October 2003

The detection of CO2 in the gas phase is possible in presence of oxygen with an amalgamated Au‐poly(tetrafluoroethylene) gas diffusion electrode and an internal electrolyte solution containing Ni(II)cyclam. For concentrations between 0.1 to 1% the electrochemical cell has a sensitivity of 3.58 mA %−1 and the detection limit is 500 ppm. In preliminary experiments at rotating disk electrodes the optimum pH‐range was found to be between 3.5 to 6 and a selectivity ratio of the catalyst for CO2/H+ of 5 : 1 could be determined. The relationship between reduction current and the square root of the angular speed is linear, indicating that the electrochemical process is limited by diffusion of CO2. Tl and Pb are presented as alternative electrode materials at which the Ni(II)cyclam catalyzed reduction of CO2 can be observed. Problems arise from fouling effects at the sensing electrode and a non‐linearity of the calibration plot at higher concentrations.
Estimating common trends in multivariate time series using dynamic factor analysis
Authors: Zuur A. F. , Fryer R. J. , Jolliffe I. T. , Dekker R. , Beukema J. J.
Published: October 2003

This article discusses dynamic factor analysis, a technique for estimating common trends in multivariate time series. Unlike more common time series techniques such as spectral analysis and ARIMA models, dynamic factor analysis can analyse short, non‐stationary time series containing missing values. Typically, the parameters in dynamic factor analysis are estimated by direct optimization, which means that only small data sets can be analysed if computing time is not to become prohibitively long and the chances of obtaining sub‐optimal estimates are to be avoided. This article shows how the parameters of dynamic factor analysis can be estimated using the EM algorithm, allowing larger data sets to be analysed. The technique is illustrated on a marine environmental data set. Copyright © 2003 John Wiley & Sons, Ltd.
Nutritional ecology and diachronic trends in Paleolithic diet and health
Authors: Hockett Bryan , Haws Jonathan
Published: October 2003

Modern nutritional studies have found that diverse diets are linked to lower infant mortality rates and longer life expectancies in humans. This is primarily because humans require more than fifty essential nutrients for growth and cell maintenance and repair; most of these essential nutrients must come from outside food sources rather than being manufactured by the body itself; and a diversity of food types is required to consume the full suite of essential nutrients necessary for optimal human health. These principles and their related affects on human adaptations and demography are the hallmarks of a theoretical paradigm defined as nutritional ecology. This essay applies concepts derived from nutritional ecology to the study of human evolution. Principles of nutritional ecology are applied to the study of the Middle‐to‐Upper Paleolithic transition in order to broadly illustrate the interpretive ramifications of this approach. At any stage in human evolution, those hominid populations that chose to diversify their subsistence base may have had a selective advantage over competitors who restricted their diet principally to one food type, such as terrestrial mammals.
Evolutionary ecology, sexual conflict, and behavioral differentiation among baboon populations
Authors: Henzi Peter , Barrett Louise
Published: October 2003

A central assumption of baboon socio‐ecological models is that all populations have the same capacity to react to different environments. The burden of our argument is that this assumption needs to be reconsidered. Data suggest not only that hamadryas, but chacma as well, differ in interesting ways from the stock baboon model that has been derived, in the main, from earlier work on anubis and cynocephalus. Although environmental factors are behind these differences, much of their influence is a consequence of their effect on restricted ancestral populations, where selection for appropriate responses to the social challenges set by local conditions now constrains the nature of individual responses to contemporary environments. Available genetic evidence suggess a southern African origin for Papio at a time when climatic conditions were certainly no better than they are now and when temperatures, if nothing else, were probably lower. In light of this, a reconstruction of how climate has structured the sexual conflict between males and female charcma, which itself hinges on infanticide, can help explain not only the East African pattern, but also how the apparently anomalous hamadryas pattern has been derived.
Developments in research concerning Mesozoic–Tertiary Tethys and neotectonics in the Isparta Angle, SW Turkey
Authors: F. Robertson Alastair H. , Poisson André , Akinci Ömer
Published: October 2003

The Isparta Angle has played a critical role in the development of concepts concerning the tectonic evolution of the Mesozoic–Tertiary Neotethys in the Eastern Mediterranean region. Following early regional studies, mainly by the Mineral Research and Exploration Institute of Turkey (MTA), during the 1960s and 1970s, a French team mapped the area and confirmed a regional tectonostratigraphy of three great allochthonous systems of mainly Mesozoic–Early Tertiary age, termed the Antalya, Lycian and Hoyran‐Beyşehir‐Hadım nappes. During the 1970s and 1980s a British group studied the Neotethyan evolution of what they termed the Antalya Complex, utilizing knowledge of plate tectonic processes. Throughout the 1970s and 1980s MTA systematically remapped the area at 1:25 000 scale. The root zone of the Antalya allochthon was either a southerly Neotethys, within and to the south of the Isparta Angle, or a northerly Neotethys, many hundreds of kilometres to the north. The southerly origin is nowadays favoured but some questions remain. Attention focused in the 1990s until present to the post‐collisional, neotectonic evolution of the Isparta Angle and its links with the neighbouring Mediterranean Sea. Here, we trace the development of research and the ongoing debates concerning alternative tectonic concepts used to explain the evolution of the Isparta Angle from Mesozoic to Recent time. We conclude by outlining several tectonic models for the evolution of the Antalya allochthon within a southerly Neotethys that require to be tested by future field studies. Copyright © 2003 John Wiley & Sons, Ltd.
New insights on the Antalya Nappes in the apex of the Isparta Angle: the Isparta Çay unit revisited
Authors: Vrielynck Bruno , Bonneau Michel , Danelian Taniel , Cadet Jean‐Paul , Poisson André
Published: October 2003

The Isparta Çay unit was defined in the valley of the Isparta Çay (river) as one of the units that constitutes the Antalya Nappes. Situated structurally between the Bey Dağları autochthon and the Miocene neo‐autochthon, the Isparta Çay unit provides decisive arguments with respect to the timing of emplacement of deep basinal units, cropping out in the central part of the Isparta Angle, as well as for a model of reconstruction of the Pamphylian Basin, located to the south of the Taurus belt. The Isparta Çay unit (previously named ‘Isparta Çay formation’) consists of a pile of thrust sheets all of which display the following basic sedimentary sequence: Triassic marls and sandstones containing plant remains and limestones with Halobia, overlying Jurassic to Cretaceous deep‐sea sedimentary rocks (radiolarites). Detailed mapping, combined with new and revised stratigraphic data, confirms the existence of a very complex pile of tectonic, rather thin sheets. The basic sequence is composed, from bottom to top, of the following sedimentary units: (1) marls and turbiditic sandstones rich in plant debris; (2) limestones interbedded with marls and; (3) regularly‐bedded cherty limestones. These three lower units contain rather abundant fossils (i.e. Halobia and ammonites) and are Triassic in age: (4) lenticular calcareous breccia in which Middle Jurassic foraminifera are found; (5) radiolarites, green and then red, including lenticular beds of reworked calcareous sands (now dolomitized and/or silicified). The radiolarians from the red radiolarites establish a Jurassic to Early Cretaceous age and; (6) red silts and clays with interbedded calcareous breccia, which are probably Cretaceous in age. The total thickness of the basic sequence as described above varies between 100 and 150 m, depending on the thickness of the lenticular breccia intercalations.

Such a sequence is frequent in the Antalya Complex as one of the deep basinal sequences. It has been interpreted as one sequence expelled from the Pamphylian Basin, located between the Anamas–Akseki platform (Western Taurus) to the NE, and the Bey Dağları platform to the SW. The age of the radiolaritic sequences of the Antalya Nappes, extended to all the units of SW Turkey, is discussed. Copyright © 2003 John Wiley & Sons, Ltd.
New data concerning the age of the Aksu Thrust in the south of the Aksu valley, Isparta Angle (SW Turkey): consequences for the Antalya Basin and the Eastern Mediterranean
Authors: Poisson André , Wernli Roland , Saǧular E. Kemal , Temi̇z Haluk
Published: October 2003

Pliocene sediments in the Aksu valley of the Antalya Neogene basin, located in the central part of the Isparta Angle, are shown to have transgressed a palaeovalley which resulted from deep erosion, probably during a sea‐level lowstand related to the Messinian salinity crisis. The southern part of the Pliocene Aksu Basin exhibits shallow, open‐marine deposits bordered by reefal limestones to the east. The dominant facies are marls and silts, which contain an abundant fauna of molluscs, foraminifera and nannoplankton of Early to Late Pliocene age. The northern part of the basin corresponds to the infill of a canyon (200 m deep) and environs by green marls overlain by massive conglomerates. The marls yielded a microfauna including nannoplankton indicative of a Mid‐Pliocene age (limit N19–N20 and NN15 and NN16). This sequence was affected by strong compression, which resulted in duplication of the succession along several flat thrust faults. Kinematic data indicate a translation towards the west and southwest, related to the regionally important Aksu Thrust. This appears to be contemporaneous with the Levant Fault system and with the thrusting in the Kyrenia Range, north Cyprus. Copyright © 2003 John Wiley & Sons, Ltd.
Origin of tufa (cool‐water carbonate) and related terraces in the Antalya area, SW Turkey
Authors: Glover Clare , Robertson Alastair H. F.
Published: October 2003

Extensive tufa deposits covering 600 km2 of the terraced Plio‐Quaternary Antalya coastal plain were deposited from cool karstic spring waters, reaching a total thickness of up to 250 m. The tufa formed within the Aksu Basin, a large N–S‐trending half‐graben bordered by the Taurus Mountains. The tufa is exposed on two main levels: an upper terrace at c. 300 m above sea level (a.s.l.) and a lower terrace at 100–200 m a.s.l. An additional terrace is reported to be submerged offshore at −50 to −100 m below sea level. Tufa deposition was preceded by Late Pliocene regression of a shallow sea. Initial tufa deposition occurred in and around small lakes ponded by N–S extensional fault blocks. The tufa was mainly precipitated in shallow lakes, marshes and sluggish streams, resulting in complex facies associations. Radiometric dating of the lower terrace yielded ages of >600 ka (the maximum resolution of the method). A climatically favourable time for maximum tufa formation was 2.0–1.5 Ma (latest Pliocene), representing a prolonged period of cool, but seasonally variable climate. This favoured carbonate dissolution, aquifer recharge and profuse, uninterrupted spring activity. Basin‐wide tufa deposition ended when the lakes and marshes shrank. Afterwards mid‐Late Quaternary climatic conditions were unsuitable for large‐scale tufa deposition. Pre‐existing tufa was then eroded, dissolved and karstified, while terra rossa soils formed. Gradual tectonic uplift continued during Quaternary time. Glacio‐eustatic sea‐level fluctuations during the mid‐Quaternary, coupled with localized stream erosion, created the second main terrace, backed by irregular cliffs and promontories. The submarine terrace possibly formed in response to Late Quaternary sea‐level fall, followed by post‐glacial submergence and sculpting of coastal cliffs. Relatively small volumes of spring water continued to flow at different levels of the terrace system, depositing high‐energy tufa in waterfalls, cascades and areas of sloping run‐off. This tufa locally forms veneers on escarpments, gorges and cliffs eroded into the pre‐existing sub‐horizontal lacustrine/paludal tufa. Copyright © 2003 John Wiley & Sons, Ltd.
Seismic catastrophes at the ancient city of Sagalassos (SW Turkey) and their implications for seismotectonics in the Burdur–Isparta area
Authors: Sintubin Manuel , Muchez Philippe , Similox‐Tohon Dominique , Verhaert Griet , Paulissen Etienne , Waelkens MARC
Published: October 2003

The ancient city of Sagalassos, situated c. 10 km south of Isparta (SW Turkey), is located on the southeastern outskirts of an area affected by a number of large earthquakes (Ms > 6.0) in the last century, and where a number of seismogenic faults are identified. Archaeological relics at Sagalassos show ample evidence that the city experienced severe earthquake damage early in the sixth century AD and in the middle of the seventh century AD. This last seismic catastrophe even seems to have caused the abandonment of the city. It is postulated that the city was situated in the macroseismic epicentre, although the causative fault has not yet been identified. Based on satellite imagery, and both geological and geomorphological field evidence in the region of Sagalassos, NE–SW‐trending and ENE–WSW‐trending tectonic lines are considered as candidates for the seismogenic faults that caused the devastating earthquakes. Copyright © 2003 John Wiley & Sons, Ltd.
Reassessment of methyl rotation barriers and conformations by correlated quantum chemistry methods
Authors: Del Rio Alberto , Boucekkine Abdou , Meinnel Jean
Published: October 2003

Internal rotations of the methyl group in ortho‐substituted and 2,6‐disubstituted toluenes in their ground state have been investigated by means of various ab initio quantum chemistry methods. Computed barriers at the Hartree‐Fock (HF) level using medium sized basis sets agreed reasonably with experimental results in the case of the studied ortho‐substituted toluenes. However, this agreement worsens when using very large basis sets. Furthermore, the determination of the conformation and barriers of more weakly hindered methyl groups, that is, for 2,6‐dihalogenotoluenes or toluene itself, necessitates high level correlated computations, because of a possible failure of HF calculations in this case. Density functional theory (DFT) techniques required, in several cases, much more extended basis sets than the post‐HF Møller‐Plesset perturbation (MP2, MP4) ones, to insure the convergence of the computed barriers. Non‐negligible variations of the computed barriers when using different DFT functionals are observed for some systems. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2093–2100, 2003
Tork: Conformational analysis method for molecules and complexes
Authors: Chang Chia‐En , Gilson Michael K.
Published: October 2003

A conformational search method for organic molecules and bimolecular complexes is presented. The method, termed Tork, uses normal‐mode analysis in bond–angle–torsion coordinates and focuses on a key subset of torsional coordinates to identify natural molecular motions that lead the initial conformation to new energy minima. New conformations are generated via distortion along these modes and their pairwise combinations, followed by energy minimization. For complexes, special treatment is accorded to the six coordinates that specify the position and orientation of one molecule relative to the other. Tests described here show that Tork is highly efficient for cyclic, acyclic, and mixed single molecules, as well as for host–guest complexes. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1987–1998, 2003
Intraprotein electrostatics derived from first principles: Divide‐and‐conquer approaches for QM/MM calculations
Authors: Molina Pablo A. , Li Hui , Jensen Jan H.
Published: October 2003

Two divide‐and‐conquer (DAQ) approaches for building multipole‐based molecular electrostatic potentials of proteins are presented and evaluated for use in QM/MM calculations. One approach is a further development of the neutralization method of Bellido and Rullmann (J Comput Chem 1989, 10, 479–487) while the other is based on removing part of the electron density before performing the multipole expansion. Both methods create systems with integer charges without using charge renormalization. To determine their performance in terms of location of cuts and distance to QM region, the new DAQ approaches are tested in calculations of the proton affinity of Nζ of Lys55 in the inhibitor turkey ovomucoid third domain. Finally, the two methods are used to build a variety of MM regions, applied to calculations of the pKa of Lys55, and compared to other computational methodologies in which force field charges are employed. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1971–1979, 2003
Constructing irregular surfaces to enclose macromolecular complexes for mesoscale modeling using the discrete surface charge optimization (DISCO) algorithm
Authors: Zhang Qing , Beard Daniel A. , Schlick Tamar
Published: October 2003

Salt‐mediated electrostatics interactions play an essential role in biomolecular structures and dynamics. Because macromolecular systems modeled at atomic resolution contain thousands of solute atoms, the electrostatic computations constitute an expensive part of the force and energy calculations. Implicit solvent models are one way to simplify the model and associated calculations, but they are generally used in combination with standard atomic models for the solute. To approximate electrostatics interactions in models on the polymer level (e.g., supercoiled DNA) that are simulated over long times (e.g., milliseconds) using Brownian dynamics, Beard and Schlick have developed the DiSCO (Discrete Surface Charge Optimization) algorithm. DiSCO represents a macromolecular complex by a few hundred discrete charges on a surface enclosing the system modeled by the Debye‐Hückel (screened Coulombic) approximation to the Poisson‐Boltzmann equation, and treats the salt solution as continuum solvation. DiSCO can represent the nucleosome core particle (>12,000 atoms), for example, by 353 discrete surface charges distributed on the surfaces of a large disk for the nucleosome core particle and a slender cylinder for the histone tail; the charges are optimized with respect to the Poisson‐Boltzmann solution for the electric field, yielding a ∼5.5% residual. Because regular surfaces enclosing macromolecules are not sufficiently general and may be suboptimal for certain systems, we develop a general method to construct irregular models tailored to the geometry of macromolecules. We also compare charge optimization based on both the electric field and electrostatic potential refinement. Results indicate that irregular surfaces can lead to a more accurate approximation (lower residuals), and the refinement in terms of the electric field is more robust. We also show that surface smoothing for irregular models is important, that the charge optimization (by the TNPACK minimizer) is efficient and does not depend on the initial assigned values, and that the residual is acceptable when the distance to the model surface is close to, or larger than, the Debye length. We illustrate applications of DiSCO's model‐building procedure to chromatin folding and supercoiled DNA bound to Hin and Fis proteins. DiSCO is generally applicable to other interesting macromolecular systems for which mesoscale models are appropriate, to yield a resolution between the all‐atom representative and the polymer level. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2063–2074, 2003
Ab initio quality properties for macromolecules using the ADMA approach
Authors: Exner Thomas E. , Mezey Paul G.
Published: October 2003

We describe new developments of an earlier linear scaling algorithm for ab initio quality macromolecular property calculations based on the adjustable density matrix assembler (ADMA) approach. In this approach, a large molecule is divided into fuzzy fragments, for which quantum chemical calculations can easily be done using moderate‐size “parent molecules” that contain all the local interactions within a selected distance. If greater accuracy is required, a larger distance is chosen. With the present extension of this approximation, properties of the large molecules, like the electron density, the electrostatic potential, dipole moments, partial charges, and the Hartree–Fock energy are calculated. The accuracy of the method is demonstrated with test cases of medium size by comparing the ADMA results with direct quantum chemical calculations. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1980–1986, 2003
Bond energies for molecules, clusters, and deposit systems
Authors: Jug Karl , Geudtner Gerald
Published: October 2003

A new approach is suggested to the assignment of bond energies in molecules and clusters. It uses a shareholder principle for the redistribution of the shifts in atomic energies, which arise in a molecule, on the bonds. The scheme is directly suitable for semiempirical methods, where only one‐ and two‐center terms occur. MSINDO calculations are performed to demonstrate the suitability of the approach for molecules and clusters. As an application the bonding in a deposit system is analyzed for the case of copper on magnesium oxide. It is found that copper atoms do not only bind to the preferred oxygen sites but also substantially to the magnesium sites. The copper‐copper bonds are the strongest and will determine the structure of copper clusters on magnesium oxide surfaces. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2013–2022, 2003
An environmental pseudopotential approach to molecular interactions: Implementation in MOLPRO
Authors: Valderrama E. , Wheatley R. J.
Published: October 2003

We present the implementation into the MOLPRO package of a model for the interaction of a central system with its surrounding environment. The properties of a target system enclosed by a noncovalently bound environment or solvent are modeled as those of a system embedded into the effective pseudopotential arising from the exact electrostatic Coulomb potential and the approximated exchange–repulsion potential. For the latter we use the charge‐density overlap model, which relates the exchange–repulsion interaction energy between two species with the overlap of their ground‐state electron charge densities. The solutions of the modified Hartree–Fock equations for the target system are obtained self‐consistently. This way the exchange–induction effects arising from the converged electron–charge density of the embedded system are implicitly included. Inclusion of the correlation effects is provided by the use of post‐Hartree–Fock and density–functional techniques available in the MOLPRO package. The computational and conceptual advantages provided by this approach are shown in the calculation of the dipole polarizabilities of halide and chalcogenide anions in different environments. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2075–2082, 2003
Inclusion of the ligand field contribution in a polarizable molecular mechanics: SIBFA‐LF
Authors: Piquemal Jean‐Philip , Williams‐Hubbard Ben , Fey Natalie , Deeth Robert J. , Gresh Nohad , Giessner‐Prettre Claude
Published: October 2003

To account for the distortion of the coordination sphere that takes place in complexes containing open‐shell metal cations such as Cu(II), we implemented, in sum of interactions between fragments ab initio computed (SIBFA) molecular mechanics, an additional contribution to take into account the ligand field splitting of the metal d orbitals. This term, based on the angular overlap model, has been parameterized for Cu(II) coordinated to oxygen and nitrogen ligands. The comparison of the results obtained from density functional theory computations on the one hand and SIBFA or SIBFA‐LF on the other shows that SIBFA‐LF gives geometric arrangements similar to those obtained from quantum mechanical computations. Moreover, the geometric improvement takes place without downgrading the energetic agreement obtained from SIBFA. The systems considered are Cu(II) interacting with six water molecules, four ammonia or four imidazoles, and four water plus two formate anions. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1963–1970, 2003
Theoretical study of the internal elimination reactions of xanthate precursors
Authors: Claes L. , François J.‐P. , Deleuze M. S.
Published: October 2003

The gas‐phase internal elimination (Ei) reaction of ethyl xanthate (CH3‐CH2‐S‐CS‐O‐CH3) has been investigated by means of Hartree–Fock, second‐order Møller–Plesset, and density functional theory (DFT) using the Becke three‐parameter Lee–Yang–Parr (B3LYP) functional and the modified Perdew–Wang one‐parameter model for kinetics (MPW1K). Considerable differences between the ground‐ and transition‐state geometries and the calculated activation energies are observed from one approach to the other, which justifies first a careful calibration of the methods against the results of benchmark CCSD(T) calculations. Compared with these, DFT calculations along with the MPW1K functional are found to be an appropriate choice for describing the Ei reaction of xanthate precursors. The precursor conformation and the transition states involved in the internal conversion of xanthate precursors of cyano derivatives of ethylene, and of cis‐ and trans‐stilbene, are then characterized in detail by means of this functional. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2023–2031, 2003
A dynamic mean field theory for dissipative interacting many‐electron systems: Markovian formalism and its implementation
Authors: Yokojima Satoshi , Chen Guanhua , Xu Ruixue , Yan Yijing
Published: October 2003

To demonstrate its applicability for realistic open systems, we apply the dynamic mean field quantum dissipative theory to simulate the photo‐induced excitation and nonradiative decay of an embedded butadiene molecule. The Markovian approximation is adopted to further reduce the computational time, and the resulting Markovian formulation assumes a variation of Lindblad's semigroup form, which is shown to be numerically stable. In the calculation, all 22 valence electrons in the butadiene molecule are taken as the system and treated explicitly while the nuclei of the molecules are taken as the immediate bath of the system. It is observed that (1) various excitations decay differently, which leads to different peak widths in the absorption spectra; and (2) the temperature dependences of nonradiative decay rates are distinct for various excitations, which can be explained by the different electron‐phonon couplings. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2083–2092, 2003
Social development: the intellectual heritage
Authors: Midgley James
Published: October 2003

Because social development is primarily concerned with practical matters, little attention has been paid to the ideas, concepts and theories that inform social development interventions. Most publications on social development make little reference to theoretical issues, and most practitioners are unaware of the conceptual derivation of their activities. However, although seldom recognized or acknowledged, social development practice has, in a subtle and indirect way, been informed and shaped by a variety of intellectual ideas that, in turn, reveal a commitment to different normative perspectives. This paper traces the contribution these perspectives have made to social development over the years. By documenting this intellectual heritage, it hopes to promote a greater awareness of theoretical issues and, at the same time, to foster social development's conceptualization. Copyright © 2003 John Wiley & Sons, Ltd.
The practice of design: developing the Chars Livelihoods Programme in Bangladesh
Authors: Brocklesby Mary Ann , Hobley Mary
Published: October 2003

This article examines development programme design, using the Chars Livelihoods Programme in Bangladesh as a case study. Central to the Programme was the need to address the deep structural barriers preventing the exercise of voice by the extreme poor. By describing how this issue was tackled in the design process, the article explores the room for manoeuvre to engage in processes of social development relating to extreme poverty by focusing on ‘citizen participation’, ‘voice’ and ‘responsiveness’. It argues that within the confines of a conventional, bureaucratic planning process, opportunities to be innovative may be limited. However, to refuse the challenge, is to disregard the role design plays in opening up spaces for future action. It concludes by arguing that design is an inherently politicised process, which involves choices about whose voice is heard, whose power is respected and whose is disputed. This issue cannot be ignored by initiatives that seek to eliminate extreme poverty through citizenship participation in development. Copyright © 2003 John Wiley & Sons, Ltd.
Social development as knowledge building: research as a sphere of policy influence
Authors: Fisher Eleanor , Holland Jeremy D.
Published: October 2003

The value of using social development knowledge as a tool for building development policy was promoted by the British bilateral donor in the late 1990s. This article takes the case of a capacity building initiative that sought to build social development knowledge as a resource for policy formulation in ‘southern’ countries. Situating knowledge as a development resource presents difficulties for intervention processes that have historically developed to provide access to economic and social assets. This article highlights some of the problems involved in trying to build social development capacity and questions the suitability of this style of intervention. Inappropriate and short‐term support for knowledge capacity building carries the danger that the traditional separation between the academic and practice spheres will be reinforced, making the process of democratising social knowledge more difficult. Copyright © 2003 John Wiley & Sons, Ltd.
Organizational meta‐scripts as a source of high reliability: the case of an army armored brigade
Authors: Zohar Dov , Luria Gil
Published: October 2003

Many high‐reliability organizations must deal with the problem of requisite cognitive variety in operators of interactively complex technological systems. The present study describes an organizational script strategy dealing with this problem, based on development of shared meta‐scripts sustained by continuous learning. Analysis of mission briefing and debriefing protocols in an armored brigade indicated that most task‐related interactions were based on script language (i.e., verbs and action phrases signifying particular meta‐scripts and relevant contingencies). These protocols suggest that script‐trained operators construe complex missions as interchangeable combinations of 15 meta‐scripts, reducing cognitive demands or requisite variety to manageable proportions. An ongoing learning process, maintained via repeated script‐based feedback during debriefings, further reduces cognitive demands by increasing available variety in operators. Implications for performance reliability in ordinary organizations are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Organizational climate as a moderator of safety knowledge–safety performance relationships
Authors: Smith‐Crowe Kristin , Burke Michael J. , Landis Ronald S.
Published: October 2003

Using training history data and supervisory ratings of 133 hazardous waste workers' safety performance collected within two organizations in the U.S. nuclear waste industry, this study examined organizational climate for the transfer of safety training as a moderator of relationships between safety knowledge and safety performance. The trend in the results was consistent with the hypothesis that these relationships would be stronger in the less restrictive (more supportive) organizational climate. The implications of these findings for promoting safe work behaviors through the creation of a positive and strategically focused organizational climate for the transfer of safety training are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Latent errors and adverse organizational consequences: a conceptualization
Authors: Ramanujam Rangaraj , Goodman Paul S.
Published: October 2003

We develop the concept of latent errors—uncorrected deviations from procedures and policies that have no direct adverse consequences—and examine the complex relationships between organizational antecedents, latent errors, and adverse consequences. Latent errors, with varying levels of frequency, are present in all organizations whereas extreme adverse outcomes are rare. Thus, all organizations become potential objects of study in research on errors. Latent errors enable the design of ex ante studies of errors that avoid sampling on the dependent variable. The basic elements of our framework focus on two critical linkages. First is the role of antecedent factors such as incentives and goals in contributing to the presence of latent errors. Second, we explore how positive and negative feedback systems and external triggers link an acceleration of latent errors with adverse organizational outcomes. We also discuss how variations in context (e.g., whether work activities are co‐located or distributed) may affect these factors. Implications for research on high‐reliability organizations are discussed. Copyright © 2003 John Wiley & Sons, Ltd.