bluuebunny/crossref_metadata_2025 huggingface dataset:
The molecular and crystal structure of p‐methyl‐phenyl glyoxylacid‐m‐trifluoro‐anilide
Authors: Hoehne E. , Seidel I.
Published: July 2007

Using X‐ray crystal structure analysis of the title compound the positions of all atoms (including all A atoms) were localized in the triclinic unit cell with the parameters a = 14.686 Å, b = 7.700 Å, c = 7.898 Å, α = 122.5°, β = 105.4°, γ = 87.7°, space group P1. The existence of an intramolecular HN … O(1) bridge was inferred, the H‐bridge acceptor of which predominantly is the π‐electron density of the carbonyl group in agreement with the results of the X‐ray crystal structure analysis of p‐methyl‐phenyl‐glyoxyl‐acid‐p‐chloroanilide (HOEHNE, SEIDEL). Moreover, the existence of H‐bridgelike interactions of the two phenyl hydrogen atoms H(6) and H(15) to the carbonyl oxygen O(2) could be proved. These interactions stabilize the conformation of the two phenyl rings in the molecule.
The crystallisation of chromite‐magnesiochromite spinels from a calcium magnesium aluminosilicate glass: Nucleation, crystal growth and final crystal sizes
Authors: Packter A. , Robson M. J.
Published: July 2007

The crystallisation of chromite‐magnesiochromite spinels was studied from a calcium magnesium aluminosilicate glass (a simulated slag) containing 3 to 12 percent total iron oxides and 0.3 to 1.5 percent chromium(III) oxide, at temperatures from 1400° to 700 °C. – Spinel crystallisation occurred in glasses with 3–7 percent FeO and 0.7–1.1 percent Cr2O3. At temperatures 1100 °C and above, the nucleation was rapid and crystal numbers very high, at FeO contents above 3 percent and Cr2O3 contents above 0.7 percent; at 1056° and 1000 °C however, the crystal numbers reached some optimum values but then decreased as clinopyroxene crystals grew onto and enveloped the spinel microcrystals. In these glasses, the crystal lengths varied with growth time according to the relation, lt = 2 kg tα = Rg1 tα, where α = 0.7–1.0: this time dependence was a compromise between a relation for dendritic growth and one for facetted growth. The growth rates generally increased about five to seven times for 160 °C temperature rise: the energy of activation for the spinel crystal growth was then estimated as 180 ± 60 kJ mole−1. – No spinel crystals were observed in glasses with more than 7 percent FeO content, only clinopyroxene crystals. Probably, these latter had nucleated rapidly and grown onto spinel microcrystals, while the spinel microcrystals were still of < 0.1 μm size.
Epitaxial growth of GaN on {1012} oriented sapphire in GaCl/NH3/He and GaCl/NH3/H2 systems
Authors: Fitzl G. , Tempel A. , Seifert W. , Butter E.
Published: July 2007

GaN epitaxial layers were grown on {1012} sapphire substrates in the systems GaCl/NH3/He and GaCl/NH3H2, respectively. The films obtained were investigated by light microscopy, RHEED method and electron‐microscopical replica technique. The epitaxial relationship was found to be {1012} // {1120}GaN; 〈1120〉 // 〈1010〉GaN With respect to layer perfection the temperature range of 800 … 1060°C and growth rates ≧ 1 μm/min are the best growth conditions.
The crystal growth in gels
Authors: Karniewicz J. , Wiktorowska B.
Published: July 2007

The paper reviews the techniques of crystal growth in gel media and collects the data on the crystals growth in gels.
The precipitation of sparingly‐soluble acid, neutral and basic metal salts from aqueous solution: Ionic equilibria at different pHs, precipitate phases and precipitation mechanisms
Authors: Packter A.
Published: July 2007

The precipitations of the sparingly‐soluble acid, neutral and basic salts of the divalent cations beryllium, magnesium, calcium, strontium, barium, manganese (II), iron (II), cobalt (II), nickel (II), copper (II), zinc, cadmium, mercury (II), tin (II) and lead (II) with the inorganic anions sulphate, chromate, molybdate, monohydrogen phosphate, phosphate, and carbonate (from supersaturated aqueous solutions) are surveyed. The different types of ionic equilibria (cation hydrolysis, anion hydrolysis, ion‐pair formation) that may influence these precipitations, at different pHs and ionic concentrations, are examined. The crystalline phases precipitated at different pHs are tabulated and the precipitation mechanisms (at different pHs) are analysed.
On the occurrence of polytypism in single crystal CdTe thin films
Authors: Tiwari Brajesh Kumar , Srivastava O. N.
Published: July 2007

Cadmium telluride thin films have been found to exhibit polytypism. The polytypes are formed when the as grown amorphous CdTe thin films undergo amorphous to crystalline transformation. The transformed single crystal regions correspond to different polytypes. Besides the well known zinc blende type 3 C cubic phase and less often found wurtzite type 2 H phase, four new polytypes (5 H, 6 H, 6 R and 15 R) the only ones known to‐date have been found in the present investigation. In addition to the new polytypes, a new structural variant has also been found. This has the same ‘c’ parameter as that of the 2 H phase but has its ‘a’ lattice parameter as ‘a0 \documentclass{article}\pagestyle{empty}\begin{document}$ a_{\rm o} \sqrt {3} $\end{document}’ (a0 being the common lattice parameter of the polytypes). A feasible mechanism making the formation of polytypes intelligible has been suggested.
The effect of dynamic recrystallization on the growth velocity of new phase crystals at polymorphic transformation of tin and thallium
Authors: Brick V. B. , Larikov L. N.
Published: July 2007

The analysis of dynamic recrystallization influencing the crystal growth of the new phase in high purity tin and thallium (99.9995%) is carried out. It is shown that in tin, in which the β → α transition proceeds on the dislocation or the normal mechanisms (depending upon a supercooling degree, ΔT) a superposition of dynamic recrystallization results in an increase of the growth velocity of α‐Sn crystals. The most distinct of acceleration is observed at −21 ÷ − 23 °C, when the growth velocity of recrystallization centers and the maximal growth velocity, Vmax, of the crystals are comparable values. The dynamic recrystallization superposition in thallium offers to transform the transformation mechanism. Thereby an erase of the features of the martensite α ⇄ β transition mechanism and an appearance of the features of the normal crystal growth mechanism of the new phase are observed.
The structure of CuCd alloys obtained electrolytically on monocrystal copper cathodes
Authors: Łagiewka E.
Published: July 2007

Tests were made on the structure of CuCd alloys obtained on single crystal copper cathodes with surfaces parallel to the (111), (110) and (100) planes. X‐ray phase identification indicated the presence of α‐phase in the form of a solid solution of cadmium in copper. In the low cathode potentials range alloy crystallite orientation is governed by twinning on the {111} planes of crystallites of epitaxial orientation relative to cathode surface. The surface morphology of alloys obtained up to potential −490 mV depend on cathode type. Above this potential value alloy surface morphology is determined by potential at which it is obtained.
EPR spectra of irradiated Na2Cr2O7 · 2 H2O crystals
Authors: Alybakov A. A. , Gubanova V. A. , Tojchiev N.
Published: July 2007

The EPR spectra of X‐irradiated Na2Cr2O7 · 2 H2O crystals grown from the aqueous solution at room temperature are studied. Three groups of lines are detected, which marked conventionally as C1, C2 and C3. Each of the C1 and C2 line groups is a superposition of two doublets. The lines are interpreted as due to the Cr5+ ions in the distorted (stretched) oxygenous tetrahedron. The doublet structure is due to hyperfine interaction with nuclei of 1/2 spin which are protons of water. It is shown that the C1 and C2 line groups are due to the centers of the same type with different orientations in the lattice. The principal g‐tensor values for these centres were as follows: gz = 1.916, gy = 1.978, gx = 1.986.
Crystal and molecular structure of piperidinium‐acet‐p‐Cl‐anilide‐bromide
Authors: Reck G.
Published: July 2007

The crystal structure of piperidinium‐acet‐p‐Cl‐anilide‐bromide is monoclinic, space group P 21/n with 8 formula units C13H18N2OBrCl in the unit cell. The lattice constants are a = 7.337(2), b = 17.865(4), c = 22.822(5) Å, and β = 94.66(1)°. The title compound is not isomorphous to the corresponding chloride. Br ions are linked to the molecules by hydrogen bonds forming chains in the crystal structure.
Studies on the preparation and characterization of the Ce2(SO4)3 · 8(H, D)2O
Authors: de Saja A. , Rull F. , Pastor J. M. , de Saja J. A.
Published: July 2007

Cerium Sulfate octohydrate crystals were crystallized from aqueous solutions under controlled conditions. The solubility measurements were carried out on temperatures between 10 and 80°. Thermoanalytical methods were applied for the study of the thermal behaviour of this compound. Raman spectra of polycrystalline Ce2(SO4)3 · 8H2O and Ce2(SO4)3 · 8D2O recorded at 80 K are reported. The vibrational modes have been assigned by comparing the spectrum of both compounds and using structural considerations.
TEM Investigations of the Influence of Strain Rate and Mode of Deformation on the Substructure of an Fe‐Ni‐C alloy
Authors: Martin U. , Hensger K.‐E. , Klimanek P.
Published: July 2007

The influence of strain rate and mode of deformation on the substructure of a Fe‐Ni‐C alloy was estimated by TEM. The softening processes during hot deformation appear as dynamic recovery and dynamic recrystallization. – The dynamic recrystallization is favoured by increased strain rate and one‐dimensional state of stress.
Energy levels of dislocations in Ge under different conditions. Comparison between images of electron‐ and light‐beam scanning microscopy
Authors: Castaldini A. , Cavallini A. , Gondi P.
Published: July 2007

Thermal treatment effects on Ge deformed at 350°C are consistent with reductions of the effective dangling bond densities on the dislocations. On account of difficulties in the application of known statistics the phenomena observed are briefly discussed by considering a heavily doped cylinder model for the dislocations. Observations with infrared beam induced currents emphasize the necessity of considering the effects of other defects, introduced together with dislocations during deformation, in particular for the interpretation of photoconductivity data.
The influence of lattice mismatch upon defects generation and luminescent characteristics of heterostructures in the GaP‐InP system
Authors: Konnikov S. G. , Popova T. B. , Ruvimov S. A. , Sobolev M. M. , Sorokin L. M. , Shulpina I. L. , Umansky V. E.
Published: July 2007

The influence of lattice mismatch and thermal stresses on the defect generation in GaAs‐GaInP heterostructures was studied. The results of electron‐probe, X‐ray topographic and electron‐microscopic investigations are presented. The comparison of X‐ray diffraction and microcathodoluminescence results is done.
Effect of generated defects during plastic deformation on electron properties of silicon
Authors: Mąkosa A.
Published: July 2007

Conductivity, photoconductivity and SDP of n‐type silicon deformed and annealed under different thermal conditions were investigated. The conductivity was found to be dependent on the temperature of deformation and additional annealing. Recombination in deformed samples is fully controlled by paramagnetic centers localized within the charge space region around the dislocations.
On the Reproducibility of the Orientation Distribution Function of Texture Samples from Pole Figures (VI). Sharp Texturs. Possibilities of Ghost Corrections
Authors: Matthies S.
Published: July 2007

The special case of sharp textures and first considerations about possible ghost correction conceptions in the problem of the reproduction of the ODF from pole figures are discussed.
Metastable zone of sodium hydrogen carbonate crystallization in ammonia‐soda process
Authors: Filipescu L. , Szanto M. , Filpescu M.
Published: July 2007

Experimental results of an investigation of metastable zone and sodium hydrogen carbonate nucleation from the included supersaturated solutions are presented. In order to attain a better crystal size distribution some temperature patterns along the cooling part of the carbonating column have been suggested. It has been shown that high crystal growth rates might be carried on smaller size carbonating columns.
Determination of distribution coefficients from measurements of mean absorption coefficients of foreign ions along the crystal growth axis distribution coefficients of complex ions in CsI crystals
Authors: Bollmann W.
Published: July 2007

An formula connecting the absorption coefficient α with the distribution coefficient k of ions is obtained by integrating PFANN'S formula and by inserting Beer's relation. It allows the determination of k of absorbing ions by measurements of α along the crystal growth axis for extended crystal regions. The distribution coefficients of BO2−, CNO−, CO3− −, IO3−, NH4+, NO2−, NO3−, OH−, and SO4− − ions in CsI crystal were determined by this method. The relations between absorption constants and concentrations are given for most of these ions.
On the reversion behaviour of an Al‐15 at.% Zn alloy between 155°C and 175°C
Authors: Wendrock G. , Löffler H.
Published: July 2007

The structural changes going on in an Al‐15 at.% Zn alloy postaged in the vicinity of the kink of the C‐curve (161°C) in the T.T.T.‐diagram after pre‐ageing at R. T. or 90°C (till start radii rS between 1.0 and 4.0 nm were obtained) were followed by means of SAXS‐investigations. The main results are the following:

No indication could be found that the reversion behaviour is remarkably changed by crossing the temperature of the kink of the C‐curve in the T.T.T.‐diagram, i.e. the reversion as well as the growth mechanism of the zones does not differ considerably below and above 161°C.

The decrease of the integral intensity Q0 during the reversion process is mainly due to both the loss of zinc content of the zones and its rise in the matrix and not essentially by the diminution of the volume fraction of the precipitates.

Zones of a start radius of about 4 nm are much more stable against the decrease of the zine content during the reversion treatment that those of 2 nm.
Influence of impurity on rhythmic crystallization of calcium carbonate in agar gel
Authors: Krishnan S. , Gnanam F. D. , Ramasamy P. , Laddha G. S.
Published: July 2007

During the gel growth of calcite crystals in test tubes, for a narrow concentration of inner and outer electrolytes we observed rhythmic crystallization of calcium carbonate. In this paper the effect of adding impurities on the pattern of periodic crystallization of calcium carbonate has been presented. The addition of impurities either increases or decreases the solubility of reaction product and hence may affect the rate of nucleation of calcium carbonate crystals. The variation of spacing coefficient and velocity constant due to the addition of impurities has also been studied.
On temperature dependence of Debye‐Waller factor in V3Si in the temperature range from 8 to 293 K
Authors: Sirota N. N. , Polutchankina L. P.
Published: July 2007

The temperature dependence of the Debye‐Waller factors of vanadium and silicon in V3Si and that of the X‐ray Debye temperature are obtained from the integral intensities of X‐ray reflection measured at 11 temperatures ranging from 8 K to 293 K. It shown that the breaks on these curves are observed at Tbr = 21.7 K. This fact allows to assume that the phase transition in this compound is accompanied by the rapid change of the atomic vibration frequencies.
HVEM In‐situ Straining Experiments on MgO Specimens Predeformed at High Temperature
Authors: Appel F. , Berezhkova G. V. , Messerschmidt U. , Perstnev P. P. , Rozhanskii V. N.
Published: July 2007

A deformation of MgO crystals at high temperature significantly increases the plasticity in a subsequent deformation at room temperture. It was shown by deformation experiments inside the high voltage electron microscope the this effects is most probably due to the homogeneous dislocation structure formed by straining at high temperature, but not to change in the processes controlling the mobility of individual dislocations.
A Czochralski crystal puller automated by the weighing method
Authors: Blumberg H. , Reiche P. , Watzinger W.
Published: July 2007

The automated crystal growing equipment makes use of a commercial electronic balance equipped with a microprocessor. The mode of operation is explained and experiences got on the occasion of crystal growth experiments are presented.
Reorientation of the long molecular axis in smectic phases
Authors: Kresse H. , Selbmann Ch. , Demus D. , Buka A. , Bata L.
Published: July 2007

The low frequency dielectric dispersion was measured of two 4‐n‐alkyloxybenzylidene‐4′‐n‐hexylaniline in nematic, smectic A, C, B, F, and G phases. The results were discussed with respect to the molecular structure and the relaxation mechanism.
Synthetic, X‐ray Diffraction, Electrochemical, and Density Functional Theoretical Studies of (Indenyl)ruthenium Complexes Containing Dithiolate Ligands
Authors: Ng Sin Yee , Tan Jialin , Fan Wai Yip , Leong Weng Kee , Goh Lai Yoong , Webster Richard D.
Published: June 2007

Halide substitution of the complexes [(Ind)Ru(L2)X] {Ind = η5‐C9H7. 1: (L2) = dppf [1,1′‐bis(diphenylphosphanyl)ferrocene], X = Cl; 2: (L2) = dppm [1,1′‐bis(diphenylphosphanyl)methane], X = Cl; and 18: (L2) = (CO)2, X = I} with the 1,1‐dithiolates –S2CNR2 (dialkyl dithiocarbamates for R = Me, Et, and C5H10), –S2COR (alkyl xanthates for R = Et and iPr), and–S2PR2 (dithiophosphinates for R = Et and Ph) showed that the lability of the indenyl ligand is influenced by the nature of both the coligand and the incoming dithiolate, as well as the solvent. In addition to dithiolate derivatives, the reactions also produced the hydride species [(Ind)Ru(diphos)H] in solvent‐ and stoichiometry‐dependent yields. The observed dependence of lability of Ind on (L2) follows the order, dppf < dppm ≈ (CO)2, in agreement with the electron‐donor capability of L2, as well as the estimation of lowest activation energy for the η5 → η3 ring slippage process in the series of complexes [(Ind)Ru(L)2(S2COMe)] (L = PMeH2, PH3, CO) for L = CO. The computational study also indicated an indenyl lability order for dithiolate substitution (dithiocarbamate > xanthate), in agreement with experimental findings. The dissociation of the indenyl ligand in chloro substitution of 1 by –S2CNEt2 was found to be exhaustive in a polar solvent like MeOH, but only partial in CH2Cl2. Cyclic voltammetry experiments indicated that [(Ind)Ru(dppf)(η1‐S2COiPr)] (10) and [(Ind)Ru(dppf)(η1‐S2PPh2)] (13) can be oxidized in one‐electron chemical irreversible or chemical reversible processes, respectively (at a scan rate of 100 mV/s), at about 0 V versus Fc/Fc+. Complex 13 underwent additional one‐electron oxidation processes at +0.5 and +0.8 V versus Fc/Fc+. The new complexes have all been characterized spectroscopically, and some (four containing the indenyl ligand and three of the non‐indenyl type) by X‐ray diffraction as well. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Preparation of Cu2O Hollow Nanospheres under Reflux Conditions
Authors: Yang Muquan , Zhang Yingwei , Pang Guangsheng , Feng Shouhua
Published: June 2007

Cuprous oxide hollow nanospheres were prepared by heating a solution of copper acetate and hydrazine as a reductant in 2‐propanol at reflux. The size distribution of the nanospheres is mainly in the range 100–200 nm. The products were characterized by X‐ray diffraction, UV/Vis diffuse reflectance spectroscopy, SEM, and TEM. The results indicated that the Cu2O hollow nanospheres aggregated from small nanoparticles with an average size of ca. 6.6 nm. The UV/Vis diffuse reflectance spectrum indicated that the optical absorption edge of the hollow Cu2O nanospheres is redshifted relative to their solid counterparts. The influence of the reaction conditions, such as reaction temperature, reaction time, and the amount of water, on the formation of the nanospheres as well as their morphology were studied. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Crystal Structure and Surface Photovoltage Properties of MnII Coordination Supramolecules
Authors: Sun Li‐Ping , Niu Shu‐Yun , Jin Jing , Zhang Li
Published: June 2007

Three MnII coordination supramolecular complexes [Mn(pdc)(H2O)]n 1, {[Mn(pdc) (phen)(H2O)]·3H2O}n 2, and {[Mn(cyan)2(H2O)4]·2HCl·2(Hcyan)} 3 (H2pdc = pyridine‐2,3‐dicarboxylic acid, Hcyan = cyanuric acid, phen = 1,10‐phenanthroline) were hydrothermally synthesized and their structures determined by single‐crystal X‐ray diffraction. The pdc group in complex 1 bridges the MnII ions to form an infinite 3D structure. In complex 2, the MnII ion is bridged to a 1D infinite chain by pdc groups and the chain is further connected to a 2D structure by hydrogen bonds. The 3D structure of complex 3 is formed by hydrogen bonds and O···Cl weak interactions. Surface photovoltage spectroscopy (SPS) of complexes 1–3 indicate that they all possess positive SPV response in the range of 300–800 nm and show p‐type semiconductor characteristic. The intensities of the SPV responses are obviously different, and this can mainly be attributed to the differences in their structures. Field‐induced surface photovoltage spectroscopy (FISPS) of complexes 1–3 confirms their p‐type semiconductor characteristic.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of Carbon and Silica Hollow Spheres with Mesoporous Shells using Polyethylene Oxide/Phenol Formaldehyde Polymer Blend
Authors: Chang‐Chien Chun‐Yi , Hsu Chun‐Han , Lee Tsung‐Ying , Liu Che‐Wei , Wu Sheng‐Ho , Lin Hong‐Ping , Tang Chih‐Yuan , Lin Chin‐Yen
Published: June 2007

Polyethylene oxide/phenol formaldehyde silica composite hollow spheres were obtained from a fast silicification of a polymer blend, containing polyethylene oxide (PEO) as silica gelator and phenol formaldehyde (PF) polymer as carbon source, in a highly diluted silica solution at pH ≈ 5.0–6.0. The PF–PEO/silica hollow spheres can be feasibly converted to mesoporous silica hollow spheres by hydrothermal treatment and calcination, and to mesoporous carbon hollow spheres after pyrolysis under a nitrogen atmosphere and silica etching. Because the formation of the hollow spheres is kinetically controlled, the diameter of the hollow spheres is dependent on the molecular weight of the PEO polymer, pH value of the silica solution, and the PF content, and the size can be tuned within a range of a few micrometers to tens of nanometers. These mesoporous hollow spheres have high surface areas and large pore sizes and volumes. In practice, the mesoporous carbon hollow spheres with an interconnected mesostructure were used as a solid template to prepare different metal oxide hollow spheres. After impregnation of the proper metal oxide precursors and calcination, the γ‐Al2O3, anatase‐TiO2, α‐Fe2O3, ZrO2, MgO, and CeO2 hollow spheres composed of nanoparticles were readily synthesize.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Enantioselective analysis of the antipsychotic 9‐hydroxyrisperidone, main metabolite of risperidone, by chiral capillary EKC using dual CDs
Authors: Danel Cécile , Chaminade Pierre , Odou Pascal , Bartélémy Christine , Azarzar Dalila , Bonte Jean‐Paul , Vaccher Claude
Published: June 2007

An analytical method for the enantioseparation of the 9‐hydroxyrisperidone, main metabolite of the antipsychotic risperidone (Risp), was developed by CD‐EKC in the dual CDs mode using anionic and neutral CDs at acidic pH 2.5. Preliminary experiments allowed us to select the more suitable couple of CDs composed of sulfated‐α‐CD and hydroxypropylated‐β‐CD. The optimization of the main experimental parameters (concentrations of both CDs and concentration of the phosphate buffer) was based on a central composite design through the response surface methodology. Then, the influence of the voltage and the temperature on the enantioseparation was studied using the classical univariate approach. The final method permits to resolve the enantiomers of the 9‐hydroxyrisperidone with a resolution of 3.13 and an analysis time of about 13 min. Finally, this method was successfully applied for the simultaneous determination of Risp and the enantiomers of 9‐hydroxyrisperidone (9‐OHRisp).
In vitro evaluation of the genotoxicity of acetamiprid in human peripheral blood lymphocytes
Authors: Kocaman Ayşe Yavuz , Topaktaş Mehmet
Published: June 2007

Acetamiprid, a neonicotinoid insecticide, is commonly used both in agriculture and domestic areas against a wide range of insects. The potential genotoxicity of a commercial formulation of acetamiprid (Mosetam 20 SP, containing 20% acetamiprid as the active ingredient) on human peripheral blood lymphocytes was examined in vitro by sister chromatid exchange (SCE), chromosomal aberrations (CAs), and micronucleus tests. Cells were treated with 25, 30, 35, and 40 μg/ml of acetamiprid for 24 and 48 hr. Acetamiprid induced SCEs and CAs significantly at all concentrations and treatment times and micronucleus formation was significantly induced at 30, 35, and 40 μg/ml of acetamiprid as compared with both the control and solvent control. Acetamiprid decreased the proliferation index (PI) at the two highest concentrations (35 and 40 μg/ml) for the 24‐hr treatment period and only at the highest concentration (40 μg/ml) for the 48‐hr treatment period when compared with the control and solvent control. Peripheral lymphocytes exposed to all concentrations of acetamiprid showed significant decreases in mitotic index (MI) and nuclear division index (NDI) for both treatment periods when compared with both the control and solvent control. Furthermore, acetamiprid decreased the MI in both treatment periods, and the NDI only in the 24‐hr treatment period to the same extent as the positive control, mitomycin C (MMC). This study presents the first in vitro evidence for the genotoxicity of a commercial formulation of acetamiprid in human peripheral lymphocytes. Environ. Mol. Mutagen., 2007. © 2007 Wiley‐Liss, Inc.
Forecasting relative quality
Authors: Uri Noel D.
Published: July 2007

This paper develops a model to forecast the likely quality rating of new automobiles. A scheme is devised and implemented for 1982 whereby the probability that a specific model will have one of five quality ratings is computed. The quality ratings are based on the trouble index computed by Consumer Reports based on a survey of its subscribers. A multinomial logit specification is used whereby the relative probability that a given level of quality is realized is a function of previous quality ratings, the location of the manufacturer of the automobile, the size of the automobile and the list price (or port‐of‐entry prices, in the case of imports). The forecast results when compared in a qualitative way to actual 1982 quality ratings prove to be acceptable.
An empirical investigation of combinations of economic forecasts
Authors: Holden K. , Peel D. A.
Published: July 2007

This paper examines the effects of combining three econometric and three times‐series forecasts of growth and inflation in the U.K. If forecasts are unbiased then a combination exploiting this fact will be more efficient than an unrestricted combination. Ex post econometric forecasts may be biased but ex ante they are unbiased. The results of the study are that a restricted linear combination of the econometric forecasts is superior to an unrestricted combination and also to the unweighted mean of the forecasts. However, it is not preferred to the best of the individual forecasts.
Long‐term forecasting with innovation diffusion models: The impact of replacement purchases
Authors: Kamakura Wagner A. , Balasubramanian Siva K.
Published: July 2007

The model presented in this paper integrates two distinct components of the demand for durable goods: adoptions and replacements. The adoption of a new product is modeled as an innovation diffusion process, using price and population as exogenous variables. Adopters are expected to eventually replace their old units of the product, with a probability which depends on the age of the owned unit, and other random factors such as overload, style‐changes etc.

It is shovn that the integration of adoption and replacement demand components in our model yields quality sales forecasts, not only under conditions where detailed data on replacement sales is available, but also when the forecaster's access is limited to total sales data and educated guesses on certain elements of the replacement process.
Decision‐analytic assessment of the economic value of weather forecasts: The fallowing/planting problem
Authors: Katz Richard W. , Brown Barbara G. , Murphy Allan H.
Published: July 2007

A decision‐analytic approach is taken to the problem of assessing the economic value of imperfect weather forecasts. Emphasis is placed on measures of the quality of such information and on the relationship between quality and economic value. The fallowing/planting problem for a spring wheat farmer is examined in detail as a specific application. It is assumed that the farmer's goal is to maximize the total expected discounted return over an infinite horizon, which places this problem within the general framework of Markov decision processes. By means of stochastic dynamic programming, the economic value to the farmer of currently available seasonal precipitation forecasts, as well as of hypothetical improvements in the quality of such forecasts, is estimated. Because the relationship between the quality and value of forecasts is highly nonlinear, the need to explicitly determine value‐of‐information estimates, rather than relying on quality as a surrogate for value, is made clear.
Small sample properties of quarterly forecast errors
Authors: Sankaran S.
Published: July 2007

There are two basic approaches used in the comparative evaluation of forecasters: (1) Statistical tests of significance of differences in error measures, (2) Ordinal rankings of forecasters. To use the first approach of statistical tests, the forecast error data must satisfy the assumptions underlying those tests. This paper examines the validity of those assumptions by enquiring into the small sample properties of the forecast error data of quarterly forecasts of the U.S. economy.
The impact on the performance of growth curve models of changes in parameter re‐estimation period and other factors
Authors: Price D. H. R. , Sharp J. A.
Published: July 2007

A simulation model of a real electricity supply undertaking was used to provide a financial performance measure for growth curve forecasting models. The impact on financial performance was determined when changes were made in (1) the method of estimating the model parameters, (2) the period between re‐estimations, (3) the growth curve fitted and (4) the amount of smoothing of the demand time‐series. The response to variation of the parameter review period was found to behave surprisingly, in that it exhibited different signs for two different estimation methods. Changes in re‐estimation period explained somewhat more of the variation in performance than did a change in growth curve. Correcting the demand series for conditions which were known to be abnormal improved performance.
Should fixed coefficients be re‐estimated every period for extrapolation?
Authors: Swamy P. A. V. B. , Schinasi Garry J.
Published: July 2007

This paper demonstrates that forecast accuracy is not necessarily improved when fixed‐coefficient models are sequentially re‐estimated and used for prediction, after updating the database with the latest observation(s). It is argued that although sequential estimation may minimize the variances of predictors based on some classes of estimators, sequential estimation does not necessarily yield accurate predictions (i.e. predictions that are close to actual realizations). Minimizing the mean squared prediction error about the actual realization is a necessary condition for maximizing the probability that one predictor is more accurate than others. This minimization need not require, and may even exclude, the most recent data. It has been shown by an example that a prediction based on a nonsequential estimate of a stochastically varying coefficient model is superior to predictions based on several sequential estimates of the fixed‐coefficient models, including a random walk model.
On multistep prediction error methods for time series models
Authors: Stoica Petre , Nehorai Arye
Published: July 2007

Multistep prediction error methods for linear time series models are considered from both a theoretical and a practical standpoint. The emphasis is on autoregressive moving‐average (ARMA) models for which a multistep prediction error estimation method (PEM) is developed. The results of a Monte Carlo simulation study aimed at establishing the possible merits of the multistep PEM are presented.
A constrained least squares method for estimating the effects of an unknown monotonically intervening factor
Authors: Thore Sten
Published: July 2007

A constrained least squares method is developed for the estimation of the effects of an unknown intervening causal factor in regression analysis, when the unknown factor shifts the regression hyperplane monotonically upwards (downwards) over time. As an illustration, we estimate the price elasticity of cigarettes in the USA and the systematic shifts of the demand curve for cigarettes during the time period 1964‐86 (these shifts presumably reflecting the heightened awareness of the general public of the potential dangers of smoking).
Judgmental extrapolation and the salience of change
Authors: Andreassen Paul B. , Kraus Stephen J.
Published: July 2007

People may often forecast using cognitive procedures that resemble formal time‐series extrapolation models. A model of judgmental extrapolation based on exponential smoothing is proposed in which the setting of the trend parameter is hypothesized to depend upon the relative salience of the successive changes. The salience hypothesis was first tested with exponential series by the use of a framing manipulation. As predicted, focusing the subjects' attention on the changes led to more accurate forecasts. In two investment simulation studies, the salience hypothesis was further examined by varying the statistical properties of the price changes. As predicted, subjects were more likely to sell as prices fell and to buy as prices rose (1) as the sample size of similar changes increased; (2) when the variance of the changes was low; and (3) when the absolute value of the mean change was high. Conditions that may influence judgmental forecasting processes are discussed.
Recovering precision from seemingly redundant rounded data
Authors: Collier Irwin L. , Baltagi Badi H.
Published: July 2007

Economic time series from the socialist economies of Eastern Europe and the Soviet Union are often not available. Instead, a matrix of rounded growth indexes for different base years is published. Using the constrained least squares and feasible GLS estimators developed in this paper, it is possible to predict the true matrix of growth indexes with greatly improved accuracy.
Parameter sensitivities, monte carlo filtering, and model forecasting under uncertainty
Authors: Rose Kenneth A. , Smith Eric P. , Gardner Robert H. , Brenkert Antoinette L. , Bartell Steven M.
Published: July 2007

Complex models are often used to make predictions of environmental effects over a broad range of temporal and spatial scales. The data necessary to adequately estimate the parameters of these complex models are often not available. Monte Carlo filtering, the process of rejecting sets of mode! simulations that fail to meet prespecified criteria of model performance, is a useful procedure for objectively establishing parameter values and improving confidence in model predictions. This paper uses a foodweb model to examine the relationship between model sensitivities and Monte Carlo filtering. Results show that Monte Carlo filtering with a behavior definition that is closely related to the sensitivity structure of the model will produce substantial reductions in model forecasting uncertainty.
Simultaneous equation estimates of electricity demand for the rural south: Revenue projection when prices are administered
Authors: McKean John R. , Winger Wendell D.
Published: July 2007

Presented are estimates of demand equations and producer revenue projections for rural farm electricity consumers in the USA. Statistical tests include a Box‐Cox comparison of functional form, a Koyck‐distributed lag, and a contrast of average versus marginal prices. Producer revenue projections take account of the estimated demand equation and non‐continuous rate schedules for each of the electricity distributors. Multiple price equilibria result from differences in administered price schedules between sellers. The ‘effective’ price elasticity based upon forecasts which take account of the market circumstances is lower than the simple demand point elasticity but higher than found in some previous studies.
Temporal aggregation and systematic sampling in structural time‐series models
Authors: González Pilar
Published: July 2007

Given a structural time‐series model specified at a basic time interval, this paper deals with the problems of forecasting efficiency and estimation accuracy generated when the data are collected at a timing interval which is a multiple of the time unit chosen to build the basic model. Results are presented for the simplest structural models, the trend plus error models, under the assumption that the parameters of the model are known. It is shown that the gains in forecasting efficiency and estimation accuracy for having data at finer intervals are considerable for both stock and flow variables with only one exception. No gain in forecasting efficiency is achieved in the case of a stock series that follows a random walk.
Analysis and forecasting of income statement account balances the dynamic interdependency and ARIMA approaches
Authors: Lin Winston T.
Published: July 2007

This paper develops a dynamic simultaneous‐equations model for analyzing and forecasting the account balances in the income statement of a firm. In the model, the income statement accounts play the role of the dependent variables that are jointly determined and explained by three types of exogenous variables: non‐controllable, performance, and controllable. The model is estimated by the three‐stage least‐squares method using annual series of data for six firms during the period from 1936 or 1950 to 1981. The immediate, delayed, and cumulated impacts of an exogenous shock on the income accounts are analyzed and the implications for managerial decisions and strategies discussed. To run as a standard of comparison for the dynamic interdependency model, the Box‐Jenkins approach is also used to develop an autoregressive integrated moving average (ARIMA) model for each of the accounts. Assessing the forecasting performance of the dynamic model against a naive model and the ARIMA and Elliott‐Uphoff models for the 1982‐4 period beyond the estimation period, we conclude that the dynamic model is a better representation of income statement accounts of the firm and increases forecasting accuracy.
Modelling the world economy: The european perspective
Authors: Artis M. , Holly S.
Published: July 2007

In this paper we provide a short description of the major developments in multi‐country modelling, and then identify where we believe models of the world economy need to develop further in order to be better able to capture interdependencies among national economies, and to address the central policy dilemmas created by the evolution of the world economy over the next decade. We then examine the policy implications of the simulations that the five modelling groups carried out.
Algorithms for explaining forecast revisions
Authors: Todd Richard M.
Published: July 2007

Forecasts are routinely revised, and these revisions are often the subject of informal analysis and discussion. This paper argues (1) that forecast revisions are analyzed because they help forecasters and forecast users to evaluate forecasts and forecasting procedures and (2) that these analyses can be sharpened by using the forecasting model to systematically express its forecast revision as the sum of components identified with specific subsets of new information, such as data revisions and forecast errors. An algorithm for this purpose is explained and illustrated.
Minimum variance prediction of bilinear time series: Direct and adaptive versions
Authors: Bielińska Ewa M.
Published: July 2007

Bilinear models of time series are considered. Minimum variance predictor for bilinear time series, homogeneous in the input and output, is proposed. Results of minimum variance prediction of bilinear time series are included. They are compared to the results of linear prediction of bilinear time series.

A minimum variance prediction algorithm for bilinear time series of the general form is developed and an adaptive version of minimum variance algorithm is derived.
An envelope function model for forecasting athletics records
Authors: Dargahi‐Noubary G. R.
Published: July 2007

The purpose of this paper is to present a multiplicative model for the fastest time per year in the 400‐ and 800‐metre races. It is composed of an envelope function and a stationary time series. The proposed model is plausible since there is dependency between the fastest times of successive years and because improvements are expected to be smaller now, as compared with several years ago. Data from the years 1860 to 1988 are used for illustration.
A non‐linear combination of experts' forecasts: A Bayesian approach
Authors: Tibiletti Luisa
Published: July 2007

A general Bayesian approach to combining n expert forecasts is developed. Under some moderate assumptions on the distributions of the expert errors, it leads to a consistent, monotonic, quasi‐linear average formula. This generalizes Bordley's results.
Forecasting load‐duration curves
Authors: Bruce Andrew , Jurke Simon , Thomson Peter
Published: July 2007

A new method is proposed for forecasting electricity load‐duration curves. The approach first forecasts the load curve and then uses the resulting predictive densities to forecast the load‐duration curve. A virtue of this procedure is that both load curves and load‐duration curves can be predicted using the same model, and confidence intervals can be generated for both predictions. The procedure is applied to the problem of predicting New Zealand electricity consumption. A structural time‐series model is used to forecast the load curve based on half‐hourly data. The model is tailored to handle effects such as daylight savings, holidays and weekends, as well as trend, annual, weekly and daily cycles. Time‐series methods, including Kalman filtering, smoothing and prediction, are used to fit the model and to achieve the desired forecasts of the load‐duration curve.
Testing for unreliable estimators and insignificant forecasts in combined forecasts
Authors: Chandrasekharan Radha , Moriarty Mark M. , Wright Gordon P.
Published: July 2007

The reliability and precision of the weights used in combining individual forecasts, irrespective of the method of combination, is important in evaluating a combined forecast. The objective of this study is not to suggest the ‘best’ method of combining individual forecasts, but rather to propose exploratory procedures, that make use of all available sample information contained in the covariance matrix of individual forecast errors, to (1) detect if the weights used in combining forecasts are ‘reliable’ (and ‘stable’ if it is known that the covariance matrix of forecast errors is stationary over time) and (2) test for ‘insignificant’ individual forecasts used in forming a combined forecast. We present empirical applications using two‐year sales and individual forecast data provided by a major consumer durables manufacturer to illustrate the feasibility of our proposed procedures.
Finite sample forecast results for vector autoregressive moving average models
Authors: Reinsel Gregory C.
Published: July 2007

Using the 'standard' approach to forecasting in the vector autoregressive moving average model, we establish basic general results on exact finite sample forecasts and their mean squared error matrices. Comparison between the exact and conditional methods of initiating the finite sample forecast calculations is presented, and a few illustrative cases are given.
Hippocampal volumetrics in depression: The importance of the posterior tail
Authors: Maller Jerome J. , Daskalakis Z. Jeff , Fitzgerald Paul B.
Published: June 2007

Studies of patients with major depression disorder (MDD) have revealed reduced hippocampal volumes, but findings have been inconsistent due to sample and measurement differences. The current study sought to measure this structure in a large sample of MDD and control subjects, using a strict measurement protocol, in order to elucidate morphological‐specific volumetric differences. Forty‐five subjects with treatment‐resistant MDD and 26 controls underwent psychiatric assessments and brain magnetic resonance imaging (MRI). The findings of this study indicate that (1) MDD results in reduced hippocampal volume, particularly in the tail section, (2) region of interest (ROI) estimation protocols and sample characteristics may help explain volumetric differences between previous MDD studies, and (3) specific ROI atrophy in treatment‐resistant depression is influenced by sex. © 2007 Wiley‐Liss, Inc.
Evidence for a specific role of the anterior hippocampal region in successful associative encoding
Authors: Chua Elizabeth F. , Schacter Daniel L. , Rand‐Giovannetti Erin , Sperling Reisa A.
Published: June 2007

It has been well established that the hippocampal formation plays a critical role in the formation of memories. However, functional specialization within the hippocampus remains controversial. Using functional magnetic resonance imaging (fMRI) during a face‐name associative encoding task, followed by a postscan recognition test for face memory and face‐name pair memory, we investigated the roles of anterior and posterior hippocampal regions in successful encoding of associations and items. Whole‐brain and region of interest (ROI) analyses revealed that the anterior hippocampal formation showed increased activation for subsequently remembered face‐name associations compared with pairs that were forgotten. In contrast, the posterior hippocampal formation showed activation above baseline during attempted encoding of face‐name pairs, but no evidence of differential activation based on subsequent memory. Furthermore, exploratory whole‐brain analyses revealed that a parahippocampal region, most likely corresponding to perirhinal cortex, showed subsequent memory effects for faces. These data provide evidence for functional specialization within the hippocampal formation based on the associative nature of the stimuli and subsequent memory. © 2007 Wiley‐Liss, Inc.