bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical Mechanics of Nearest Neighbor Systems
Authors: Montroll Elliott W.
Published: January 2005

In many solids the intermolecular forces are sufficiently short ranged so that practically the entire potential energy of the system results from interactions between nearest neighbors. The thermodynamic properties of a solid with respect to a given coordinate, α, (for example, in a ferromagnetic system α might represent the excess unpaired electron spin at a given lattice point; or in a substitutional binary alloy α might denote which of the two possible kinds of atoms are at a given lattice point) can be found from the factor of the partition function which averages over all possible configurations of α at all lattice points.

Here the evaluation of such a factor of the partition function is reduced to the calculation of the largest characteristic value of a linear homogeneous operator equation involving the potential energy between two adjacent layers of lattice points in the solid. By assuming that all possible configurations of a layer are equally probable, a lower bound for the partition function for a simple cubic lattice is found in terms of the partition function of a cube of eight molecules.

The operator equation for a real crystal becomes quite complex, but in some problems it is possible to obtain characteristic vectors and characteristic values (and thus the partition function) at high and low temperatures. For intermediate temperatures a theory of resonance between the low temperature ``almost ordered'' characteristic vectors and the high temperature ``almost disordered'' characteristic vectors is developed. In cases where the operator equation can be solved for microcrystals a few layers thick, a perturbation method is discussed in which interactions between the individual microcrystals are treated as perturbations.

Some remarks are made concerning phase transitions and finally the general theory is applied to a superficial treatment of two-dimensional ferromagnetic plates.
Raman Spectrum of Di-Tertiary-Butyl Ether
Authors: Cleveland Forrest F.
Published: January 2005

Raman displacements, estimated intensities and depolarization factors are listed for ditertiary-butyl ether, (CH3)3COC(CH3)3, in the liquid state and the results are compared with previous data for di-normal-butyl and di-isobutyl ethers. A tentative assignment of the observed lines to frequencies of the di-tertiary-butyl ether molecule is made.
Size-dependent melting of Bi nanoparticles
Authors: Olson E. A. , Efremov M. Yu. , Zhang M. , Zhang Z. , Allen L. H.
Published: January 2005

Nanocalorimetry was used to investigate the melting of Bi nanoparticles. The particles were formed by evaporating Bi onto a silicon nitride substrate, which was then heated. The particles self-assemble into truncated spherical particles. Below 5-nm average film thickness, mean particle sizes increased linearly with deposition thickness but increased rapidly for 10-nm-thick films. As expected, small particles were found to exhibit size-dependent melting temperatures less than the bulk melting temperature (e.g., ΔT=67K for a 3-nm radius particle). The measured melting temperatures for particles below ∼7nm in radius, however, were ∼50K above the value predicted by the homogeneous melting model. We discuss this discrepancy in terms of a possible size-dependent crystal structure change and the superheating of the solid phase.
Superconductor/ferromagnet current source
Authors: Golubović D. S. , Morelle M. , Moshchalkov V. V.
Published: January 2005

We demonstrate that a multiply connected superconducting structure in combination with a perpendicularly magnetized magnetic dot can be used as a current source for superconducting elements and as an external phase shifter. The concept has been tested by measuring the superconducting Tc(B) phase boundary and critical current of an Al superconducting loop placed on the top of a micron-sized Co∕Pd magnetic dot. A pronounced asymmetry in the voltage–current characteristic of the loop with respect to the polarity of the external magnetic field, as well as a shift of the Tc(B) phase boundary along the field axis indicate the presence of a persistent current in the loop.
Visualization of flow patterning in high-speed centrifugal microfluidics
Authors: Grumann Markus , Brenner Thilo , Beer Christian , Zengerle Roland , Ducrée Jens
Published: January 2005

This work presents a new experimental setup for image capturing of centrifugally driven flows in disk-based microchannels rotating at high frequencies of up to 150Hz. To still achieve a micron-scale resolution, smearing effects are minimized by a microscope-mounted CCD camera featuring an extremely short minimum exposure time of 100ns, only. The image capture is controlled by a real-time PC board which sends delayed trigger signals to the CCD camera and to a stroboscopic flash upon receiving the zero-crossing signal of the rotating disk. The common delay of the trigger signals is electronically adjusted according to the spinning frequency. This appreciably improves the stability of the captured image sequences. Another computer is equipped with a fast framegrabber PC board to directly acquire the image data from the CCD camera. A maximum spatial resolution ranging between 4.5μm at rest and 10μm at a 150Hz frequency of rotation is achieved. Even at high frequencies of rotation, image smearing does not significantly impair the contrast. Using this experimental setup, the Coriolis-induced patterning of two liquid flows in 300-μm-wide channels rotating at 100Hz is visualized at a spatial resolution better than 10μm.
(
Pb
,
Ca
)
Ti
O
3
∕
(
Pb
,
La
)
Ti
O
3
∕
(
Pb
,
Ca
)
Ti
O
3
heterostructure characterized as ferroelectric multifunctional material
Authors: Poyato Rosalia , Calzada M. Lourdes , Pardo Lorena
Published: January 2005

Ferroelectric thin films are multifunctional materials with applications in a wide range of microelectronic and microelectromechanical devices. The recent investigations on multilayer heterostructures builtup with ferroelectric layers of different compositions have shown an enhancement of the dielectric, ferroelectric, and pyroelectric properties with respect to the single-component films. In this work, the structural, dielectric, ferroelectric, and pyroelectric properties of a (Pb,Ca)TiO3∕(Pb,La)TiO3∕(Pb,Ca)TiO3 multilayer heterostructure have been studied and compared with identically prepared (Pb,Ca)TiO3 and (Pb,La)TiO3 films. The heterostructure shows a higher dielectric permittivity in the whole temperature interval up to the transition temperature, and a higher tetragonal distortion with respect to the single-component films, revealing a lower residual stress in the heterostructure. Optimized ferroelectric and pyroelectric properties have been achieved in the heterostructure, with maximum values of remanent polarization, Pr, and pyroelectric coefficient, γ, of Pr=27μCcm−2 and γ=51×10−9Ccm−2K−1. A mechanism of stress relaxation by plastic deformation through vacancies diffusion is proposed to explain the enhanced properties.
Optical properties of self-assembled ZnTe quantum dots grown by molecular-beam epitaxy
Authors: Yang C. S. , Lai Y. J. , Chou W. C. , Chen W. K. , Lee M. C. , Kuo M. C. , Lee J. , Shen J. L. , Jang D. J. , Cheng Y. C.
Published: January 2005

The morphology and the size-dependent photoluminescence (PL) spectra of the type-II ZnTe quantum dots (QDs) grown in a ZnSe matrix were obtained. The coverage of ZnTe varied from 2.5 to 3.5 monolayers (MLs). The PL peak energy decreased as the dot size increased. Excitation power and temperature-dependent PL spectra are used to characterize the optical properties of the ZnTe quantum dots. For 2.5- and 3.0-ML samples, the PL peak energy decreased monotonically as the temperature increased. However, for the 3.5-ML sample, the PL peak energy was initially blueshifted and then redshifted as the temperature increased above 40K. Carrier thermalization and carrier transfer between QDs are used to explain the experimental data. A model of temperature-dependent linewidth broadening is employed to fit the high-temperature data. The activation energy, which was found by the simple PL intensity quenching model, of the 2.5, 3.0, and 3.5 MLs were determined to be 6.35, 9.40, and 18.87meV, respectively.
Signal processing algorithm of a position sensitive detector using amplitude modulation/demodulation
Authors: La Jongpil , Park Kyihwan
Published: January 2005

The signal processing algorithm for a position sensitive detector (PSD) using an amplitude modulation/demodulation algorithm is addressed in this article. Dark currents and the external noises such as daylight and fluorescent lights are eliminated by using the amplitude modulation/demodulation and a low pass filter. The proposed amplitude modulation/demodulation method for the PSD sensor is compared with a pulse amplitude modulation method (PAM). The proposed amplitude modulation method is proved to be more accurate and robust than the PAM method by using analysis and experiments. Multiple measurements technique using one PSD sensor by the amplitude modulation/demodulation is also addressed. The power variation of light source is compensated by the normalization process using a divider.
Performance of annealed hybrid silicon heterojunctions: A numerical computer study
Authors: Rubinelli F. A. , Marsal L. F. , Pallarès J.
Published: January 2005

The performance of the standard hydrogenated amorphous silicon carbon–crystalline silicon solar cell is extensively compared with the performance of a hybrid structure subjected to a high-temperature annealing processing. Our analysis indicates that high-temperature-annealed heterojunctions show more robustness in the presence of energy offsets and defective amorphous-crystalline interfaces. Annealed hybrid cells are also less vulnerable to the negative impact of amorphous silicon carbon doped layers with poor electrical properties. Furthermore, annealed structures have the potential to generate higher efficiencies than conventional heterojunctions regardless of the wafer quality. The presence of boron at the amorphous-crystalline interface and in the wafer front region plays an important role in annealed hybrid structures that are made with low-quality wafers or where there is a highly defective amorphous-crystalline interface. In this scenario, a linear boron profile in the wafer front region is more appropriate, for which there is an optimum thickness. For low defect amorphous-crystalline interfaces and high-quality wafers, a boron exponential profile is more appropriate when boron creates additional defects in the front region of the wafer. The shape of the boron profile becomes less relevant when the boron does not add additional defects to the front region of high-quality wafers and when the amorphous-crystalline interface is low defect or defect-free.
Characteristics of a carbon nanotube field-effect transistor analyzed as a ballistic nanowire field-effect transistor
Authors: Natori Kenji , Kimura Yoji , Shimizu Tomo
Published: January 2005

A general expression of the current–voltage characteristics of a ballistic nanowire field-effect transistor (FET) is derived. At T=0, the conductance, which is equal to the quantum conductance multiplied by the number of channels at zero bias, decreases stepwise toward current saturation as the drain bias is increased. The current–voltage characteristics of a single-wall carbon nanotube FET in ballistic conduction are discussed based on the band structure of the nanotube. When both the gate overdrive and the drain bias are equal to 1V, the device made of a (19,0) nanotube and a 2-nm high-k gate insulator (ε=40ε0) flows a current of 183μA, which amounts to a current density 48 times as large as the counterpart of a silicon device. The high performance originates from a high carrier density due to the enhanced gate capacitance, and a large carrier velocity caused by the large group velocity of the original graphene band. Quantum capacitance also plays an important role in the device’s characteristics.
The role of N in the resputtering inhibition of Si in W–Si–N reactively sputtered thin layers
Authors: Vomiero A. , Boscolo Marchi E. , Mariotto G. , Della Mea G. , Scandurra A. , Puglisi O.
Published: January 2005

W–Si–N thin films were synthesized by reactive sputtering of W5Si3 target in an Ar∕N2 mixed atmosphere. The nitrogen atomic concentrations within the films ranged between 0 and 60at.%, as revealed by Rutherford backscattering measurements. At low nitrogen atom fluxes an intense Si resputtering was observed, leading to the formation of a W-rich layer with respect to target composition. The characterization of plasma parameters during the deposition, carried out with the help of a Langmuir probe, suggests that the Ar neutral atoms reflected by W atoms of the target are the main responsibilities of Si resputtering with respect to charged species, whose resputtering effect is less important. The inhibition of this phenomenon takes place with growing nitrogen concentration. The preferential formation of Si–N bonds with respect to W–N bonds was unveiled by both x-ray photoelectron spectroscopy and Fourier transform infrared absorption spectroscopy. This also justifies the inhibition of Si resputtering. A comparison with literature data concerning W–Si–N systems sputtered at different plasma conditions was performed in order to highlight the influence of plasma parameters on the composition of the layers.
Functional Integral Representation of Nonequilibrium Statistical Mechanics
Authors: Popielawski Jan , Rice Stuart A. , Hurt Norman
Published: January 2005

A functional integral representation of the Green's function of the Liouville equation is presented, and it is shown how the weak-coupling expansion and the binary-collision expansion are generated from the functional integral. Furthermore, when the interaction between particles is represented as a sum of short- and long-ranged components, it is possible to generate a new ``mixed'' expansion. It is shown how this mixed expansion may be used to derive a kinetic equation descriptive of the liquid phase. Under the conditions that successive correlated binary encounters may be neglected and that the effects of the weak interaction on the dynamics of the quasibinary encounter are neglected, the Rice—Allnatt equation is recovered. A discussion of the implications of the derivation is given along with a brief description of those diagrams of the Prigogine theory which are summed in the Rice—Allnatt approximation.
Coherent precipitation in the TbCu7-type GdCo-based ribbons prepared by simple processing
Authors: Rong Chuan-Bing , Zhang Hong-Wei , Zhang Jian , Du Xiao-Bo , Zhang Shao-Ying , Shen Bao-Gen
Published: January 2005

Isotropic Gd(Co0.88−xCuxFe0.09Zr0.03)7 (x=0.10–0.20) ribbons with TbCu7 structure have been prepared by melt-spinning technique. A uniform and fine cellular microstructure consisting of 2:17 cell with 1:5 cell-boundary phase is developed by simply slow cooling the ribbons from 850 to 400°C without the standard solid solution and isothermal aging treatments. It is interesting to note that the original grain boundary of 1:7 phase still exists in the precipitation-hardened ribbons and the crystallographic texture is formed in each 1:7 granular region after the treatment. This gives a way to fabricate the textured magnets with nanostructure. Positive temperature coefficients of remanence and coercivity are observed in the ribbons. The coercivity mechanism of the precipitation-hardened ribbons is discussed at the temperature ranging from room temperature to 600°C. It is proposed that the residual 1:7 phase boundaries act as effective pinning sites at high temperatures.
Hard x-ray microscopy with a 130nm spatial resolution
Authors: Youn Hwa Shik , Baik Soo Yeun , Chang Chang-Hwan
Published: January 2005

We have developed a new full field x-ray microscope at the beam line 1B2 of PLS (Pohang Light Source). It was designed to operate at the energy between 7 and 12keV. High efficiency hard x-ray zone plates, condenser and objective, have been chosen as x-ray lenses. The spatial resolution of the microscope is better than 130nm at 6.95keV.
Flash x-ray radiography using imaging plates for the observation of hypervelocity objects
Authors: Mizusako F. , Ogasawara K. , Kondo K. , Saito F. , Tamura H.
Published: January 2005

Flash x-ray radiography was conducted using imaging plates (IP) to observe high-speed thermal spray jets and debris clouds produced from hypervelocity impact. The radiographs of the spray jets or debris cloud shadows on the IPs were analyzed to estimate the distribution of mass per unit area, i.e., Areal mass density, due to the distribution of the intensities of stimulated emissions from the IPs. The wide dynamic range of the IPs led to the detection of an Areal mass density one hundred times as large as the minimum Areal mass density and the very detailed densities. The availability of the IPs for the flash x-ray radiography of a high-speed thermal spray jet and a hypervelocity-impact-produced debris cloud was demonstrated.
Structure and magnetic entropy change of melt-spun LaFe11.57Si1.43 ribbons
Authors: Yan A. , Müller K.-H. , Gutfleisch O.
Published: January 2005

The structure and magnetic entropy change of melt-spun LaFe11.57Si1.43 ribbons have been investigated. Here, the 1:13 phase with cubic NaZn13-type structure is obtained by a short-time annealing (1000°C∕1h) in melt-spun-type materials, which in contrast, requires a much longer time annealing at high temperature to develop in the bulk alloy. The Curie temperature is increased from 192K in bulk alloy to 198 and 210K in the melt-spun ribbons prepared at 20 and 40m∕s, respectively, which is attributed to more Si dissolved in the 1:13 phase when the cooling rate increases. The maximal magnetic entropy changes with a change in the magnetic field of 0–5T are 21.2 and 17.8J∕kgK in the melt-spun ribbons prepared at 20 and 40m∕s, respectively, which are close to that of bulk alloy with the same composition subjected to a prolonged heat treatment (21.1J∕kgK). Further analysis confirms the occurrence of a first-order field-induced transition in these three samples. The significantly reduced magnetic and thermal hysteresis and the large value of magnetic entropy change make the melt-spun-type materials prepared at 20m∕s more appropriate for magnetic refrigerant applications, compared with conventional bulk alloys.
Electron-beam diagnostic for space-charge measurement of an ion beam
Authors: Roy Prabir K. , Yu Simon S. , Henestroza Enrique , Eylon Shmuel , Shuman Derek B. , Ludvig Jozsef , Bieniosek Frank M. , Waldron William L. , Greenway Wayne G. , Vanecek David L. , Hannink Ryan , Amezcua Monserrat
Published: January 2005

A nonperturbing electron-beam diagnostic system for measuring the charge distribution of an ion beam is developed for heavy ion fusion beam physics studies. Conventional diagnostics require temporary insertion of sensors into the beam, but such diagnostics stop the beam, or significantly alter its properties. In this diagnostic a low energy, low current electron beam is swept transversely across the ion beam; the measured electron-beam deflection is used to infer the charge density profile of the ion beam. The initial application of this diagnostic is to the neutralized transport experiment (NTX), which is exploring the physics of space-charge-dominated beam focusing onto a small spot using a neutralizing plasma. Design and development of this diagnostic and performance with the NTX ion beamline is presented.
Measurement of absolute electron density with a plasma impedance probe
Authors: Blackwell David D. , Walker David N. , Amatucci William E.
Published: January 2005

A small spherical probe is used in conjunction with a network analyzer to determine the impedance of the probe-plasma system over a wide frequency range. Impedance curves are in good agreement with accepted circuit models with plasma-sheath and electron plasma frequency resonances easily identifiable. Clear transitions between capacitive and inductive modes as predicted by the model are identified. Sheath thickness and absolute electron density are determined from the location of these transitions. The absolute electron density indicated by the location of the impedance resonance is compared to measurements using the plasma oscillation method.
Measurement of thermal conductivity of thin films with a Si-N membrane-based microcalorimeter
Authors: Zink B. L. , Revaz B. , Cherry J. J. , Hellman F.
Published: January 2005

We describe a method of measuring thermal conductivity of films as thin as 15 nm from 2–300 K and in magnetic fields up to at least 8 T using a silicon-nitride membrane based microcalorimeter. The thermal transport in the membrane is measured before and after a sample film is deposited on the membrane. Accurate knowledge of the geometry of the microcalorimeter allows the thermal conductivity of the sample film to be determined from the difference of these measurements. We demonstrate the method for two thin film samples, a 16 nm thick Au film and a 200 nm Pb film. Results are in good agreement with the expected thermal conductivity. Below 10 K, surface scattering effects in the nitride membrane become important and limit the usefulness of this technique in some cases. Above 100 K radiative loss becomes important; we describe a method for correcting for this, taking advantage of its temperature dependence.
Ultrahigh vacuum apparatus for quartz crystal microbalance measurements in the temperature range 4–400 K
Authors: Bruschi L. , Carlin A. , de Mongeot F. Buatier , dalla Longa F. , Stringher L. , Mistura G.
Published: January 2005

We describe an apparatus for friction experiments on molecularly thin films carried out with the quartz crystal microbalance technique (QCM) in ultrahigh vacuum (UHV) and at a temperature as low as 4 K. Through the implementation in the UHV chamber of standard cryogenic procedures, the temperature of the quartz can be controlled with a resolution better than 5 mK below 10 K. The main chamber is provided with a stainless steel jacket that allows a quick change of the various temperature inserts (cryocooler head, liquid nitrogen insert, Peltier-cell stage, etc.) that span the working range 4–400 K, without ever breaking the vacuum. The crystal mounting is compatible with UHV conditions and with the Omicron standard and guarantees a good thermal and electrical contact over the entire temperature range. Once inserted in the copper sample holder, the quartz frequency and amplitude stabilities are found to be as good as the best recorded values achieved with QCMs mounted in standard high-vacuum, liquid bath cryostats. This apparatus can also be used for general QCM investigations in surface science, like the determination of film growth in deposition and sputter processes, the stoichiometry of submonolayer oxide films, and the measurement of adsorbate sticking probability.
Brucella
coopts the small GTPase Sar1 for intracellular replication
Authors: Celli Jean , Salcedo Suzana P. , Gorvel Jean-Pierre
Published: January 2005

The pathogen
Brucella abortus
resides inside macrophages within a unique, replication-permissive organelle that is derived from the endoplasmic reticulum (ER). Although dependent on the
Brucella
type IV secretion system VirB, the mechanisms governing the biogenesis of this compartment remain elusive. Here, we investigated a putative role of the early secretory pathway in ER membrane accretion by the
Brucella
-containing vacuoles (BCVs). We show that BCVs interact with ER exit sites (ERES), and blockade of Sar1 activity, which disrupts ERES, prevents intracellular replication of
Brucella
. In cells expressing the dominant interfering form Sar1[T39N], BCVs do not acquire ER membranes, suggesting that they are unable to mature into replicative organelles. By contrast, treatments that block subsequent secretory events do not affect bacterial replication. We propose that Sar1-dependent ERES functions, but not subsequent secretory events, are essential for the biogenesis of the
Brucella
replicative compartment and, thus, bacterial replication. These results assign an essential role for Sar1 in pathogenesis of an intracellular bacterium.
Enantioselectivity in environmental safety of current chiral insecticides
Authors: Liu Weiping , Gan Jianying , Schlenk Daniel , Jury William A.
Published: January 2005

Chiral pesticides currently constitute about 25% of all pesticides used, and this ratio is increasing as more complex structures are introduced. Chirality occurs widely in synthetic pyrethroids and organophosphates, which are the mainstay of modern insecticides. Despite the great public concerns associated with the use of insecticides, the environmental significance of chirality in currently used insecticides is poorly understood. In this study, we resolved enantiomers of a number of synthetic pyrethroid and organophosphate insecticides on chiral selective columns and evaluated the occurrence of enantioselectivity in aquatic toxicity and biodegradation. Dramatic differences between enantiomers were observed in their acute toxicity to the freshwater invertebrates
Ceriodaphnia dubia
and
Daphnia magna
, suggesting that the aquatic toxicity is primarily attributable to a specific enantiomer in the racemate. In field sediments, the (-) enantiomer of
cis
-bifenthrin or
cis
-permethrin was preferentially degraded, resulting in relative enrichment of the (+) enantiomer. Enantioselective degradation was also observed during incubation of sediments under laboratory conditions. Enantioselectivity in these processes is expected to result in ecotoxicological effects that cannot be predicted from our existing knowledge and must be considered in future risk assessment and regulatory decisions.
Selective Inactivation of a Fas-associated Death Domain Protein (FADD)-dependent Apoptosis and Autophagy Pathway in Immortal Epithelial Cells
Authors: Thorburn Jacqueline , Moore Franklin , Rao Anuradha , Barclay Wendy W. , Thomas Lance R. , Grant Ken W. , Cramer Scott D. , Thorburn Andrew
Published: January 2005

Although evasion of apoptosis is thought to be required for the development of cancer, it is unclear which cell death pathways are evaded. We previously identified a novel epithelial cell death pathway that works in normal cells but is inactivated in tumor cells, implying that it may be targeted during tumor development. The pathway can be activated by the Fas-associated death domain (FADD) of the adaptor protein but is distinct from the known mechanism of FADD-induced apoptosis through caspase-8. Here, we show that a physiological signal (tumor necrosis factor-related apoptosis-inducing ligand) can kill normal epithelial cells through the endogenous FADD protein by using the novel FADD death domain pathway, which activates both apoptosis and autophagy. We also show that selective resistance to this pathway occurs when primary epithelial cells are immortalized and that this occurs through a mechanism that is independent of known events (telomerase activity, and loss of function of p53, Rb, INK4a, and ARF) that are associated with immortalization. These data identify a novel cell death pathway that combines apoptosis and autophagy and that is selectively inactivated at the earliest stages of epithelial cancer development.
Service elimination decision‐making
Authors: Argouslidis Paraskevas C. , McLean Fiona
Published: January 2005

Despite the importance of the ability of service firms to rationalise their service ranges in today's competitive environment, the area of service elimination decision‐making is one of the least researched in the literature on services marketing. Responding to this knowledge gap, this paper reports part of the findings of a broader exploratory investigation into the service elimination process in the British financial services sector. In detail, the paper presents qualitative and quantitative empirical evidence on the way in which British financial institutions audit their service range in order to identify financial services as candidates for elimination. The evidence showed that the British financial institutions studied follow a periodically conducted service range auditing process, which is often documented and computer‐aided. The audit is operationalised by a set of financial and non‐financial audit criteria (performance dimensions). The evidence also showed that the service range auditing process is not static but dynamic. As such, the relative importance of the audit criteria used varies in relation to service‐specific, organisational and environmental variables, such as type of financial service, business strategy pursued overall, degree of market orientation, intensity of competition, intensity of legislation and rhythm of technological change.
Capabilities for strategic flexibility: a cognitive content framework
Authors: Combe Ian A. , Greenley Gordon E.
Published: January 2005

Different forms of strategic flexibility allow for reactive adaptation to different changing environments and the proactive driving of change. It is therefore becoming increasingly important for decision makers to not only possess marketing capabilities, but also the capabilities for strategic flexibility in its various forms. However, our knowledge of the relationships between decision makers' different ways of thinking and their capabilities for strategic flexibility is limited. This limitation is constraining research and understanding. In this article we develop a theoretical cognitive content framework that postulates relationships between different ways of thinking about strategy and different information‐processing demands. We then outline how the contrasting beliefs of decision makers may influence their capabilities to generate different hybrid forms of strategic flexibility at the cognitive level. Theoretically, the framework is embedded in resource‐based theory, personal construct theory and schema theory. The implications for research and theory are discussed.
Managing a firm's behavior through market orientation development: some empirical findings
Authors: Gounaris Spiros P. , Avlonitis George J. , Papastathopoulou Paulina
Published: January 2005

While significant empirical work exists around the conceptualization of the notion of market orientation, as well as its relation to company performance, little empirical work has attempted to sketch how a firm's behavior alters when the principles of market orientation are adopted. In this study, the authors investigate empirically the notion of market orientation continuum, according to which companies can be classified depending on the degree of adoption. Next, the behavioral implication of the company's position on the continuum is investigated. Moreover, the role of the company's market environment in explaining the degree of market orientation adoption and its classification along this continuum is also assessed. Finally, the behavioral consequences of this classification are considered.
Factors predicting the effectiveness of celebrity endorsement advertisements
Authors: Silvera David H. , Austad Benedikte
Published: January 2005

This research examines whether consumers infer that celebrity endorsers like the products they endorse, and presents a model using these inferences and other characteristics of the endorser to predict attitudes toward the endorsed product. Participants in two experiments examined written endorsement advertisements and were asked to infer the extent to which the endorser truly liked the advertised product and to rate the endorser's attractiveness, similarity to themselves, and knowledge of the product. Attitudes toward the advertisement, the endorser and the product were also measured. The resulting model indicated that product attitudes were predicted by inferences about the endorser's liking for the product and by attitudes toward the endorser.
Attributions on dissatisfying service encounters
Authors: Poon Patrick S. , Hui Michael K. , Au Kevin
Published: January 2005

Based on the proposition that deprivation of control is a key instigator of attribution thoughts, this study explores cross‐national variations in consumers' formation and consequences of attributions on dissatisfying service encounters. We hypothesize that variations in the stage of economic development and the cultural dimension of long‐term versus short‐term orientation affect consumers' perceived level of control in and attributions of dissatisfying service encounters, and the relative effects of various attribution dimensions (including locus, controllable‐by‐organization, and stability) on consumers' switching intentions. Results obtained from a cross‐national survey show that compared to PRC consumers, Canadian consumers experience more deprivation of control in dissatisfying service encounters and exhibit stronger self‐serving biases in forming attributions about their dissatisfying service experiences. Moreover, the controllable‐by‐organization dimension (i.e. whether the problems of the service encounter could be controlled by the service firm) is found to have a stronger effect on the switching intentions of Canadian consumers than that of PRC consumers, while the opposite is found for the stability dimension (i.e. whether the same problem would recur in experiences with the service firm). Managerial implications for multinational service firms, particularly in terms of service recovery strategy for Chinese and Western consumers, are discussed.
The H2A.Z/H2B dimer is unstable compared to the dimer containing the major H2A isoform
Authors: Placek Brandon J. , Harrison L. Nicole , Villers Brooke M. , Gloss Lisa M.
Published: January 2005

The nucleosome, the basic fundamental repeating unit of chromatin, contains two H2A/H2B dimers and an H3/H4 tetramer. Modulation of the structure and dynamics of the nucleosome is an important regulation mechanism of DNA‐based chemistries in the eukaryotic cell, such as transcription and replication. One means of altering the properties of the nucleosome is by incorporation of histone variants. To provide insights into how histone variants may impact the thermodynamics of the nucleosome, the stability of the heterodimer between the H2A.Z variant and H2B was determined by urea‐induced denaturation, monitored by far‐UV circular dichroism, intrinsic Tyr fluorescence intensity, and anisotropy. In the absence of stabilizing agents, the H2A.Z/H2B dimer is only partially folded. The stabilizing cosolute, trimethylamine‐N‐oxide (TMAO) was used to promote folding of the unstable heterodimer. The equilibrium stability of the H2A.Z/H2B dimer is compared to that of the H2A/H2B dimer. The equilibrium folding of both histone dimers is highly reversible and best described by a two‐state model, with no detectable equilibrium intermediates populated. The free energies of unfolding, in the absence of denaturant, of H2A.Z/H2B and H2A/H2B are 7.3 kcal mol−1 and 15.5 kcal mol−1, respectively, in 1 M TMAO. The H2A.Z/H2B dimer is the least stable histone fold characterized to date, while H2A/H2B appears to be the most stable. It is speculated that this difference in stability may contribute to the different biophysical properties of nucleosomes containing the major H2A and the H2A.Z variant.
NMR structure of HI0004, a putative essential gene product from Haemophilus influenzae, and comparison with the X‐ray structure of an Aquifex aeolicus homolog
Authors: Yeh Deok Cheon , Parsons Lisa M. , Parsons James F. , Liu Fang , Eisenstein Edward , Orban John
Published: January 2005

The solution structure of the 154‐residue conserved hypothetical protein HI0004 has been determined using multidimensional heteronuclear NMR spectroscopy. HI0004 has sequence homologs in many organisms ranging from bacteria to humans and is believed to be essential in Haemophilus influenzae, although an exact function has yet to be defined. It has a α–β–α sandwich architecture consisting of a central four‐stranded β‐sheet with the α2‐helix packed against one side of the β‐sheet and four α‐helices (α1, α3, α4, α5) on the other side. There is structural homology with the eukaryotic matrix metalloproteases (MMPs), but little sequence similarity except for a conserved region containing three histidines that appears in both the MMPs and throughout the HI0004 family of proteins. The solution structure of HI0004 is compared with the X‐ray structure of an Aquifex aeolicus homolog, AQ_1354, which has 36% sequence identity over 148 residues. Despite this level of sequence homology, significant differences exist between the two structures. These differences are described along with possible functional implications of the structures.
The mechanism of inhibition of the cyclin‐dependent kinase‐2 as revealed by the molecular dynamics study on the complex CDK2 with the peptide substrate HHASPRK
Authors: Bártová Iveta , Otyepka Michal , KřÍž Zdeněk , Koča Jaroslav
Published: January 2005

Molecular dynamics (MD) simulations were used to explain structural details of cyclin‐dependent kinase‐2 (CDK2) inhibition by phosphorylation at T14 and/or Y15 located in the glycine‐rich loop (G‐loop). Ten‐nanosecond‐long simulations of fully active CDK2 in a complex with a short peptide (HHASPRK) substrate and of CDK2 inhibited by phosphorylation of T14 and/or Y15 were produced. The inhibitory phosphorylations at T14 and/or Y15 show namely an ATP misalignment and a G‐loop shift (∼5 Å) causing the opening of the substrate binding box. The biological functions of the G‐loop and GxGxxG motif evolutionary conservation in protein kinases are discussed. The position of the ATP γ‐phosphate relative to the phosphorylation site (S/T) of the peptide substrate in the active CDK2 is described and compared with inhibited forms of CDK2. The MD results clearly provide an explanation previously not known as to why a basic residue (R/K) is preferred at the P2 position in phosphorylated S/T peptide substrates.
Regulation of protein activity with small‐molecule‐controlled inteins
Authors: Skretas Georgios , Wood David W.
Published: January 2005

Inteins are the protein analogs of self‐splicing RNA introns, as they post‐translationally excise themselves from a variety of protein hosts. Intein insertion abolishes, in general, the activity of its host protein, which is subsequently restored upon intein excision. These protein elements therefore have the potential to be used as general molecular “switches” for the control of arbitrary target proteins. Based on rational design, an intein‐based protein switch has been constructed whose splicing activity is conditionally triggered in vivo by the presence of thyroid hormone or synthetic analogs. This modified intein was used in Escherichia coli to demonstrate that a number of different proteins can be inactivated by intein insertion and then reactivated by the addition of thyroid hormone via ligand‐induced splicing. This conditional activation was also found to occur in a dose‐dependent manner. Rational protein engineering was then combined with genetic selection to evolve an additional intein whose activity is controlled by the presence of synthetic estrogen ligands. The ability to regulate protein function post‐translationally through the use of ligand‐controlled intein splicing will most likely find applications in metabolic engineering, drug discovery and delivery, biosensing, molecular computation, as well as many additional areas of biotechnology.
When an epithelium ceases to exist – an ultrastructural study on the fate of the embryonic coelom in Epiperipatus biolleyi (Onychophora, Peripatidae)
Authors: Mayer Georg , Ruhberg Hilke , Bartolomaeus Thomas
Published: January 2005

It is an accepted fact that fusion between the coelomic cavities and the primary body cavity occurs during development in the Arthropoda. However, such a fusion is much disputed in the Onychophora. In order to clarify this subject, the fate of embryonic coelomic cavities has been studied in an onychophoran. Ultrastructural investigations in this paper provide evidence that embryonic coelomic cavities fuse with spaces of the primary body cavity in Epiperipatus biolleyi. During embryogenesis, the somatic and splanchnic portions of the mesoderm separate and the former coelomic linings are transformed into mesenchymatic tissue. The resulting body cavity therefore represents a mixture of primary and secondary (coelomic) body cavities, i.e. the ‘mixocoel’. The nephridial anlage is already present, when the ‘mixocoel’ is formed, although there is no trace of a sacculus yet. The lumen of the nephridial anlage, thus, communicates with the newly formed ‘mixocoel’. Accordingly, the lumen of the nephridial sacculus cannot be regarded as a kind of ‘persisting coelomic cavity’ in E. biolleyi. Our findings support the hypothesis that the ‘mixocoel’ was already present in the common stem species of the Onychophora and Euarthropoda.
Ultrastructural study of the jaw structures in two species of Ampharetidae (Annelida: Polychaeta)
Authors: Tzetlin Alexander B.
Published: January 2005

Two species of jaw bearing Ampharetidae (Adercodon pleijeli (Mackie 1994) and Ampharete sp. B) were investigated in order to describe the microanatomy of the mouth parts and especially jaws of these enigmatic polychaetes. The animals of both studied species have 14–18 mouth tentacles that are about 30 µm in diameter each. In both species, the ventral pharyngeal organ is well developed and situated on the ventral side of the buccal cavity. It is composed of a ventral muscle bulb and investing muscles. The bulb consists of posterior and anterior parts separated by a deep median transversal groove. In both species, the triangular teeth or denticles are arranged in a single transversal row on the surface of the posterior part of the ventral bulb just in front of its posterior edge. There are 36 denticles in Adercodon pleijeli and 50 in Ampharete sp. B. The height of the denticles (6–12 µm) is similar in both species. Each tooth is composed of two main layers. The outer one (dental) is the electron‐dense sclerotized layer that covers the tooth. The inner one consists of long microvilli with a collagen matrix between them. The thickness of the dental layer ranges from 0.95 to 0.6 µm. The jaws of the studied worms may play a certain role in scraping off microfouling. The fine structure of the jaws in Ampharetidae is very similar to that of the mandibles of Dorvilleidae, the mandibles and the maxillae of Lumbrineridae, Eunicidae and Onuphidae, and the jaws of other Aciculata. This type of jaw is characterized by unlimited growth and the absence of replacement. The occurrence of jaws in a few smaller Ampharetidae is considered as an apomorphic state.
Ultrastructure of the digestive tract of Diacyclops thomasi (Cyclopoida, Copepoda) during different stages of encystment during a summer diapause
Authors: Baud Alexandra , Cuoc C. , Alekseev V.
Published: January 2005

Baud, A., Cuoc, C. and Alekseev, V. 222_. Ultrastructure of the digestive tract of Diacyclops thomasi (Cyclopoida, Copepoda) during different stages of encystment during a summer diapause. — Acta Zoologica (Stockholm) 85: 181–189

Diacyclops thomasi (Forbes, 1882) has a life cycle comprising a summer diapause with whole‐body encystment at the copepodid IV stage. Formed progressively, the cyst can indicate the extent of entry into diapause. In this study the ultrastructure of the midgut epithelium during encystment of CIV was compared with that of active CIV and females.

In active individuals two well‐differentiated epithelial cell types were observed: vacuolar cells (B‐cells), and cells without vacuoles but with more densely packed microvilli and abundant rough endoplasmic reticulum and mitochondria (F/R cells). In encysted specimens a striking transformation of the midgut epithelial layer was noted. Only inactive nuclei with highly concentrated euchromatin and encircled by a thin rim of hyaloplasm were observed. Compartments of both urosome and especially cephalothorax displayed large lipid‐rich lacunae. At the beginning of encystment, the midgut epithelium showed an intermediate state.

Changes in ultrastructure observed in the midgut epithelium of D. thomasi clearly reflect different stages of diapause, and represent clear evidence of profound reorganization, which is progressively induced by diapause in the organism.
Stomach expression of histo‐blood group antigens A and B in some vertebrates
Authors: Sarafian Victoria S. , Tomova Elena S. , Kalaydjiev Svetoslav K.
Published: January 2005

Histo‐blood group antigens (HBGA) are genetically determined glycoproteins and glycolipids expressed not only on human erythrocytes but also in vertebrate tissues. Direct evidence for the immunobiological importance of their tissue localization in the evolutionary aspect is still lacking.

The present study examines the expression of A and B HBGA in the stomach of free‐living vertebrates belonging to: Chondrichthyes, Actinopterygii, Amphibia, Reptilia, Aves, and Mammalia.

HBGA were detected immunohistochemically on stomach paraffin sections from 11 species. In all classes from Actinopterygii to Mammalia HBGA expression was confined to stomach mucosa only. Antigenic heterogeneity in the pattern of expression and localization was observed. Smooth muscle tissue, endothelial and red blood cells were immunonegative, except for the reptileEmys orbicularis.

Our results present the first comparative evidence for the expression of HBGA in the stomach of 11 free‐living vertebrate species from six classes, some of which have never been studied so far. It could be assumed that A and B antigens are constant and conservative structures with almost similar tissue localization. Their immunobiological role in the animal gastrointestinal tract might be possibly related to cell differentiation and homeostasis maintenance which would contribute to sustain the evolutionary stable ABH antigen cellular expression.
Assessment of the Tricuspid Valve Morphology by Transthoracic Real‐Time‐3D‐Echocardiography
Authors: Schnabel Renate , Khaw Alexander V. , Von Bardeleben Ralph Stephan , Strasser Christina , Kramm Thorsten , Meyer Jürgen , Mohr‐Kahaly Susanne
Published: January 2005

Aim: To demonstrate the feasibility of transthoracic three‐dimensional real‐time echocardiography (3D‐TTE) supplemental to routine assessments of the tricuspid valve and to analyze interrater agreement. Methods: Twenty healthy subjects and 74 patients with right ventricular failure were examined with conventional 2D and additionally 3D‐TTE (SONOS 7500, Philips, Netherlands). The 3D exams were performed and recorded by one of two raters. The recordings were evaluated offline and independently by both raters for visualization of morphological and functional features of the tricuspid valve according to a subjective 3‐point scale. Statistical analyses were performed for interrater agreement and for comparison of imaging quality between the two study groups. In addition, we present an illustrative case report. Results: Visualization of the spatial relationship between the tricuspid valve and vicinal structures, of the commissures, the orifice, and entirety of valve depiction were better in the ventricular failure group as compared to the control group. Annular dimensions were equally assessable in both groups, leaflet thickness and mobility were not significantly different. Interrater agreement on assessability was slight for leaflet thickness, fair for leaflet mobility and orifice area, and good for the remaining features. The 3D‐TTE exam including offline evaluation took 6.5 minutes on average and maximally 14 minutes. Conclusion: 3D‐TTE of the tricuspid valve can be performed in addition to routine 2D echocardiography within a reasonable time and with high assessability of important features in patients with right ventricular failure. Interrater agreement was fair to good overall. Thus, its feasibility may encourage prospective studies on its potential for more detailed noninvasive diagnosis and preoperative planning.