bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the concentration of H2–D2 mixtures on their triple-point dewetting behavior
Authors: Tibus S. , Sohaili M. , Klier J. , Leiderer P.
Published: October 2003

Triple-point dewetting of pure gases like hydrogen and deuterium on solid substrates is a well-known phenomenon. This property persists even for the mixed system of H2 and D2. There exists an effective triple-point temperature T3(mix), between the T3 of pure H2 and that of pure D2, which depends on the species concentrations. We present new investigations for a wide range of H2–D2 concentrations measured under different thermodynamic conditions. This allows us to map out T3(mix) as function of concentration, which can be different in the melting or solidifying direction. Furthermore, it turns out that the time the system needs to reach an equilibrium state can be very long and depends on concentration. This is not observed for the pure H2 and D2 systems. Sometimes the relaxation times are so extremely long that significant hysteresis occurs during ramping of the temperature, even if this is done very slowly on a scale of hours. This behavior can be understood on the basis of mixing and demixing processes. Possible differences in the species concentrations in the gas, liquid, and especially solid phase of the system are discussed. A preliminary phase diagram of the H2–D2 system is established.
Structural fluctuations and aging processes in deeply frozen proteins
Authors: Schlichter J. , Ponkratov V. V. , Friedrich J.
Published: October 2003

Frozen proteins are nonergodic systems and are subject to two types of structural motions, namely relaxation and fluctuation. Relaxation manifests itself in aging processes which slow the fluctuations. Within certain approximations we are able to experimentally separate the aging dynamics from the fluctuation dynamics by introducing two time parameters, namely an aging time ta and a waiting time tw. Both processes follow power laws in time. The fluctuation dynamics shows features of universality characterized by a rather uniform exponent of 1/4. These universality features were shown to be possible due to a random walk on a 1D random trajectory in conformational phase space. A very interesting aspect of protein dynamics concerns the influence of the host solvent on structural motions of the protein cores. We present results for sugar solvents and discuss possible mechanisms.
Towards a first-principles picture of the oxide–water interface
Authors: Zhang Changjun , Lindan Philip J. D.
Published: October 2003

We apply first-principles molecular dynamics and static calculations in the study of several layers of water adsorbed at an oxide surface. Our aim is to bridge the gap between the well-explored monolayer and the complex, little-understood oxide–water interface by probing this middle ground where there is still contact with vacuum surface experiments. By examining coverages up to three monolayers on rutile TiO2(110) we emerge with three major conclusions. First, there is a trend with increasing coverage for water near the surface to become more molecular in nature, viz. the coordination of H to O for all near-surface molecules tends to lower values as the coverage increases. This means the hydroniumlike and other partially dissociated structures predicted up to 1.5 monolayers become less favorable as the coverage increases. Second, the templating influence of the surface disrupts the structure of the second and third layers at 3 ML coverage. Third, we can make a very satisfactory interpretation of experimental results (HREELS and TPD) gaining some new insights in the process. The assignment of TPD peaks to layer-by-layer desorption is shown to be open to question, as some second-layer molecules may contribute to the same peak as do those in the third layer.
The role of geometric constraints in amphiphilic self-assembly: A Brownian dynamics study
Authors: Bourov Geuorgui K. , Bhattacharya Aniket
Published: October 2003

We use a stochastic molecular dynamics simulation method to investigate the effect of optimal head group area in amphiphilic self-assembly. For a fixed tail geometry, we choose several sizes of the effective head group area and carry out a detailed study of how this affects the critical micelle concentration (CMC), the cluster distribution, and the shape of micelles for different concentrations and temperature. We find that with an increase of the effective head group area, the CMC is attained at a larger concentration of the free chains at all temperatures. Likewise, for a given concentration, amphiphiles with the larger effective head group exhibit a sharper cluster distribution with a tendency to form more spherical micelles. Our study shows a way to control the size and shape of the micelles and can have potential impact on the synthesis of nano-structures through surfactant mediated templating methods.
Rotational spectra and temperature evaluation of C2 molecules produced by pulsed laser irradiation to a graphite–water interface
Authors: Saito Kotaro , Sakka Tetsuo , Ogata Yukio H.
Published: October 2003

Temperature of an ablation plume produced by pulsed laser irradiation to a graphite target submerged in water was evaluated as a function of time by analyzing the emission spectra of C2 molecules. The method is based on the determination of rotational temperature from the rotational spectra of the (0,0) Swan band of C2 molecules. In the time range shorter than 1000 ns from the ablation laser pulse, the rotational temperature of ∼6000 K was obtained. After 1000 ns it decreases rapidly, in contrast to the temperature obtained for the irradiation in air, where the decrease of the temperature is rather slow. The linewidth obtained as one of the fitting parameters suggests the high density and high pressure of this region. Temporal behavior of the laser ablation plume in water is discussed.
Gold catalyzed growth of silicon nanowires by plasma enhanced chemical vapor deposition
Authors: Hofmann S. , Ducati C. , Neill R. J. , Piscanec S. , Ferrari A. C. , Geng J. , Dunin-Borkowski R. E. , Robertson J.
Published: October 2003

Silicon nanowires were selectively grown at temperatures below 400 °C by plasma enhanced chemical vapor deposition using silane as the Si source and gold as the catalyst. A detailed growth study is presented using electron microscopy, focused ion beam preparation, and Raman spectroscopy. A radio-frequency plasma significantly increased the growth rate. The Si nanowires show an uncontaminated, crystalline silicon core surrounded by a 2-nm-thick oxide sheath. The as-grown diameters are small enough for the observation of quantum confinement effects. Plasma activation could allow a further decrease in deposition temperature. A growth model for plasma enhanced nanowire growth is discussed.
Canard phenomenon and localization of oscillations in the Belousov–Zhabotinsky reaction with global feedback
Authors: Rotstein Horacio G. , Kopell Nancy , Zhabotinsky Anatol M. , Epstein Irving R.
Published: October 2003

The occurrence of spatial domains of large amplitude oscillation on a background of small amplitude oscillation in a reaction–diffusion system is called localization. We study, analytically and numerically, the mechanism of localization in a model of the Belousov–Zhabotinsky reaction subject to global feedback. This behavior is found to arise from the canard phenomenon, in which a limit cycle suddenly undergoes a significant change in amplitude as a bifurcation parameter, in this case the feedback strength, is varied. In the system studied here, the oscillations arise via a supercritical Hopf bifurcation, but our analysis suggests that the same mechanism is relevant for systems undergoing a subcritical Hopf bifurcation.
Water dimer hydrogen bond stretch, donor torsion overtone, and “in-plane bend” vibrations
Authors: Keutsch Frank N. , Braly Linda B. , Brown Mac G. , Harker Heather A. , Petersen Poul B. , Leforestier Claude , Saykally Richard J.
Published: October 2003

We report the measurement and analysis of 64 new Ka=0←0,1 and Ka=1←0,1 transitions of (H2O)2 and 16 new Ka=0←0 transitions of (D2O)2 by terahertz laser vibration–rotation–tunneling spectroscopy of a planar supersonic expansion between 140.5 and 145.5 cm−1. The transitions in both isotopomers correspond to A′ vibrations assigned to the hydrogen bond stretch (translational) and donor torsion overtone vibrations. The interchange splitting is 56.3 GHz in Ka=0 of the excited state of (H2O)2, nearly 3 times the value of the ground state, and the bifurcation tunneling splitting is 1.8 GHz, over 2 times the value of the ground state. We compare the existing experimental spectra with calculations on state-of-the-art intermolecular potential energy surfaces and critically review the vibrational assignments reported in the literature. We show that the discrepancy between theory and experiment regarding the assignment of the feature near 103 cm−1 can be resolved by considering E2→E1 transitions, which had not been considered previously.
Efficient extreme ultraviolet emission from xenon-cluster jet targets at high repetition rate laser illumination
Authors: Ter-Avetisyan Sargis , Vogt Ulrich , Stiel Holger , Schnürer Matthias , Will Ingo , Nickles Peter V.
Published: October 2003

We studied extreme ultraviolet (EUV) emission from Xe cluster jet targets irradiated with high repetitive ps and ns laser pulses in the intensity range between 1011 and 1015 W/cm2. It was found that at fixed intensity the conversion efficiency of the laser energy into the EUV emission is higher for ns pulses. In the intensity range used no saturation of the 13.4 nm signal could be reached. At ns pulse duration a conversion efficiency 0.26%@13.4 nm in 2π steradian and 2.2% bandwidth was reached. The laser energy deposition is discussed in relation to the plasma dynamics of the cluster target. We demonstrated that due to the high flow velocity of the cluster jet target an exposition with laser pulses up to 125 kHz repetition rate is possible without any degradation of the EUV emission efficiency. Both the high conversion efficiency and the high repetition rate make this Xe target attractive for an EUV source with high average EUV power.
Interface formation and energy level alignment of pentacene on SiO2
Authors: Watkins N. J. , Gao Yongli
Published: October 2003

We examined the interface formed by pentacene deposition onto a SiO2 substrate. We found that upon pentacene deposition onto SiO2 the pentacene vacuum level aligns with that of SiO2. We observe the immediate appearance of a measurable pentacene highest occupied molecular orbital upon deposition of as little as 2 Å of pentacene onto the SiO2 surface. This suggests that there are no chemical bonds at these interfaces. Measurements that examine the behavior of pentacene deposited onto SiO2 show ordered growth of pentacene with no sign of chemical interaction or charge transfer.
Nonlinear frequency shift of a coherent dust-acoustic wave in the presence of dust-acoustic turbulence
Authors: Yi Sumin , Ryu Chang-Mo , Yoon Peter H.
Published: October 2003

The nonlinear frequency shift of a low-frequency, coherent dust-acoustic wave in the presence of higher frequency dust-acoustic turbulence is investigated in the framework of weak turbulence theory. It is found that the frequency shift of the dust-acoustic wave in an unmagnetized dusty plasma is always positive irrespective of the propagation direction of the coherent wave. It is also found that turbulent waves propagating in the same direction as the coherent wave are shown to give rise to a much higher frequency shift than the opposite case. Finally, it is shown that the nonlinear frequency shift of a dust-acoustic wave is more pronounced than in the case of the customary ion-acoustic waves in fully ionized plasmas.
Size effects on the onset of plastic deformation during nanoindentation of thin films and patterned lines
Authors: Choi Yoonjoon , Van Vliet Krystyn J. , Li Ju , Suresh Subra
Published: October 2003

Plastic deformation of materials exhibits a strong size dependence when the relevant physical length scales are in the range of microns or below. Recent progress in experimental and computational nanoindentation allows us to investigate the mechanical response of nanoscale material volumes, particularly the transition from elastic to plastic deformation and the early stages of plastic deformation. We present a systematic experimental study of nanoindentation on continuous films and unidirectionally patterned lines on substrates to explore the effects of two size scales (film thickness t and linewidth w) on the early stages of plastic deformation via the investigation of the nanoindentation P–h response. The observed experimental trends indicate that early stage plasticity is strongly size dependent, a feature that cannot be rationalized on the basis of continuum concepts. Computational simulations of these nanoindentation experiments through finite element modeling and molecular dynamics are conducted to elucidate the mechanisms by which this incipient plasticity progresses in the material by correlating observations from both experiments and computations.
Dynamics of blobs in scrape-off-layer/shadow regions of tokamaks and linear devices
Authors: Yu G. Q. , Krasheninnikov S. I.
Published: October 2003

Linear and nonlinear stability of blob propagation in the tokamak scrape off layer (SOL) and in the SOL/shadows of linear devices are studied. It is found that the most stable blobs, which can propagate as coherent structures for large distance, are the blobs with some specific spatial scale. Larger blobs are subject to the Rayleigh–Taylor (RT) instability, which breaks the blob apart and effectively reduces the scale of new structures. Smaller blobs evolve into mushroom structures typical for nonlinear stages of the RT and Richtmyer–Meshkov instabilities in fluids. Biasing of divertor targets can affect the dynamics of blob propagation. For a large magnitude of biasing potential, a strong deformation and even disintegration of the blob as a coherent structure were observed while the blob passes through the biased region.
Energy spectra of two-electron two-dimensional quantum dots confined by elliptical and bowl-like potentials
Authors: Sun Lian-Liang , Ma Feng-Cai , Li Shu-Shen
Published: October 2003

The laterally confining potential of quantum dots (QDs) fabricated in semiconductor heterostructures is approximated by an elliptical two-dimensional harmonic-oscillator well or a bowl-like circular well. The energy spectrum of two interacting electrons in these potentials is calculated in the effective-mass approximation as a function of dot size and characteristic frequency of the confining potential by the exact diagonalization method. Energy level crossover is displayed according to the ratio of the characteristic frequencies of the elliptical confinement potential along the y axis and that along the x axis. Investigating the rovibrational spectrum with pair-correlation function and conditional probability distribution, we could see the violation of circular symmetry. However, there are still some symmetries left in the elliptical QDs. When the QDs are confined by a “bowl-like” potential, the removal of the degeneracy in the energy levels of QDs is found. The distribution of energy levels is different for the different heights of the barriers.
Three-dimensional magnetohydrodynamic simulations of in situ shock formation in the coronal streamer belt
Authors: Zaliznyak Yu. , Keppens R. , Goedbloed J. P.
Published: October 2003

A numerical study of an idealized magnetohydrodynamic (MHD) configuration consisting of a planar wake flow embedded into a three-dimensional (3D) sheared magnetic field is presented. The simulations investigate the possibility for in situ development of large-scale compressive disturbances at cospatial current sheet–velocity shear regions in the heliosphere. Using a linear MHD solver, the systematical investigation of the destabilized wavenumbers, corresponding growth rates, and physical parameter ranges for dominant 3D sinuous-type instabilities in an equilibrium wake–current sheet system was done. Wakes bounded by sufficiently supersonic (Mach number Ms>2.6) flow streams are found to support dominant fully 3D sinuous instabilities when the plasma beta is of order unity. Fully nonlinear, compressible 2.5D and 3D MHD simulations show the self-consistent formation of shock fronts of fast magnetosonic type. They carry density perturbations far away from the wake’s center. Shock formation conditions are identified in sonic and Alfvénic Mach number parameter space. Depending on the wake velocity contrast and magnetic field magnitude, as well as on the initial perturbation, the emerging shock patterns can be plane-parallel as well as fully three-dimensionally structured. Similar large-scale transients could therefore originate at distances far above coronal helmet streamers or at the location of the ecliptic current sheet.
Existence of suitable weak solutions of complex Ginzburg–Landau equations and properties of the set of singular points
Authors: Liu Xiaofeng , Jia Houyu
Published: October 2003

In this paper, we consider the supercritical complex Ginzburg–Landau equation. We discuss the existence of suitable weak solution in Ω, where Ω is a bounded domain in Rn or the whole space. We also discuss the properties of the set of the singular points of the suitable weak solution in Rn, which means that the possible singular points are located in a bounded ball for any given time and there is no singular point on the whole space after limited time.
Morphology and domain pattern of L1 ordered FePt films
Authors: Li G. Q. , Takahoshi H. , Ito H. , Saito H. , Ishio S. , Shima T. , Takanashi K.
Published: October 2003

Magnetic force microscope (MFM) was used to characterize the L10 ordered FePt(001) films sputter deposited directly on MgO(001) substrates at an elevated temperature. With the change of nominal thickness (tN), the morphology varied from isolated particles to continuous films. The coercivity showed a marked change at the percolation boundary of tN≅45 nm, where the film morphology changed from a discontinuous to a continuous state. Below tN=45 nm, the coercivity did not change apparently, though the number of single-domain particles increased gradually with decreasing tN. At tN=20 nm, a critical (maximum) size of single domain particles, d=180 nm, was obtained from a size distribution, which was taken from the atomic force microscope/MFM measurement. The value calculated for this critical size was found to be d=155 nm in the assumption that the particles had ellipsoidal shape. The slight difference between experimental and theoretical values is likely to be attributed to an axis ratio (c/a) distribution of particles.
Contact angle-based predictive model for slip at the solid–liquid interface of a transverse-shear mode acoustic wave device
Authors: Ellis Jonathan S. , McHale Glen , Hayward Gordon L. , Thompson Michael
Published: October 2003

We have revisited the Blake–Tolstoi theory [Coll. Surf. 47, 135 (1990)] for molecular and hydrodynamic slip and applied it to the fundamental description of acoustic wave devices coupled to a liquid of finite thickness. The aim is to provide a framework for a predictive model for slip, based on surface–liquid interactions and contact angle. This theory provides a description of slip that links hydrodynamic boundary slip to a schematic, molecular description involving the wettability of the liquid–solid interface. We redevelop the model, using current acoustic sensors notation, then evaluate its qualitative behavior as a predictive model for slip length in the context of acoustic wave devices. Finally, we discuss the limitations of the model and consider the advantages of a predictive model for boundary slip.
Shouldering in B diffusion profiles in Si: Role of di-boron diffusion
Authors: Hwang Gyeong S. , Goddard William A.
Published: October 2003

The role of di-boron diffusion in evolution of B diffusion profiles has been investigated. We find that boron pair (Bs–Bi) diffusion can become as important as boron-interstitial pair (Bs–Sii) diffusion when both boron concentration and annealing temperature are very high, leading to concentration-dependent B diffusion. Our simulated B diffusion profiles with dramatic shouldering are in excellent agreement with experimental ones reported by Schroer et al. [Appl. Phys. Lett. 74, 3996 (1999)] for high-temperature (≈1200 °C) postimplantion annealing of ultralow-energy (≈500 eV) implanted high-concentration (>1019 cm−3) boron in silicon.
Activation spectroscopy of electronically induced defects in solid Ne
Authors: Grigorashchenko O. N. , Rudenkov V. V. , Savchenko E. V. , Khizhnyi I. V. , Frankowski M. , Smith-Gicklhorn A. M. , Beyer M. K. , Bondybey V. E.
Published: October 2003

Thermally stimulated luminescence (TSL) and thermally stimulated exoelectron emission (TSEE) methods were used in combination with cathodoluminescence to probe electronically induced defects in solid Ne. The defects were generated by a low energy electron beam. For spectroscopic study we used Ar* centers in Ne matrix as a model system. At a temperature of 10.5 K a sharp decrease in the intensity of “defect” components in the luminescence spectrum was observed. From the analysis of the corresponding peak in the TSL and TSEE yields, the trap depth energy was estimated and compared with available theoretical calculations. The obtained data support the model suggested by Song, that stable electronically induced defects have the configuration of second-neighbor Frenkel pairs.
Discrimination of local radiative and nonradiative recombination processes in an InGaN/GaN single-quantum-well structure by a time-resolved multimode scanning near-field optical microscopy
Authors: Kaneta Akio , Mutoh Takashi , Kawakami Yoichi , Fujita Shigeo , Marutsuki Giichi , Narukawa Yukio , Mukai Takashi
Published: October 2003

Precise identification of recombination dynamics based on local, radiative, and nonradiative recombination has been achieved at room temperature in a blue-light-emitting InxGa1−xN/GaN single-quantum-well structure by comparing the photoluminescence (PL) spectra taken by illumination-collection mode (I-C mode) and those by illumination mode (I-mode) in scanning near-field microscopy. The PL data mapped with PL lifetimes, as well as with PL spectra, revealed that the probed area could be classified into four different regions whose dominating processes are (1) radiative recombination within a probing aperture, (2) nonradiative recombination within an aperture, (3) diffusion of photogenerated excitons/carriers out of an aperture resulting in localized luminescence, and (4) the same diffusion process as (3), but resulting in nonradiative recombination.
Chaotic particle motion and beam halo formation induced by image-charge effects in a small-aperture alternating-gradient focusing system
Authors: Zhou Jing , Qian B. L. , Chen Chiping
Published: October 2003

It is shown with a test-particle model that image-charge effects induce a new mechanism for chaotic particle motion and halo formation in an intense charged-particle beam propagating through an alternating-gradient focusing channel with a small aperture, circular, perfectly conducting pipe. This mechanism occurs for a well-matched beam with the Kapchinskij–Vladimirskij distribution. The percentage of beam loss to the conductor wall is calculated as a function of propagating distance and aperture size.
Light-induced narrowing of excitonic absorption lines in GaN
Authors: Trautman P. , Pakuła K. , Bożek R. , Baranowski J. M.
Published: October 2003

The fundamental absorption edge of GaN has been investigated in GaN/AlxGa1−xN heterostructures. A broad excitonic line is observed after the sample has been cooled in darkness. A metastable narrowing occurs and three excitonic absorption lines are observed after the sample has been illuminated. Measurements of this effect have been made as a function of temperature and photon energy. It seems that the broadening is induced by an electric field present around dislocations in GaN. This field is reduced by free carriers created during illumination, which results in narrowing of the excitonic lines.
High-resolution bistable nematic liquid crystal device realized on orientational surface patterns
Authors: Kim Jong-Hyun , Yoneya Makoto , Yokoyama Hiroshi
Published: October 2003

The four-fold symmetry of a checkerboard-like surface alignment consisted of square domains arrived at the macroscopic orientational bistability of nematic liquid crystals. Switching between the two orientations took place with an appropriate electric field. Here the threshold field of bistable switching decreased as temperature increased, and the light could heat only the selected region in the cell including a light-absorbing medium. Irradiating the laser concurrently with an electric field, we addressed a selected region in the alignment pattern without the disturbance of neighboring regions. Extending this process, we realized an extremely fine bistable device of nematic liquid crystal with a pixel size down to about 2 μm.
Atomic resolution noncontact atomic force/scanning tunneling microscopy using a 1 MHz quartz resonator
Authors: Heike Seiji , Hashizume Tomihiro
Published: October 2003

A 1 MHz quartz length extension resonator is used as a force sensor for a noncontact atomic force/scanning tunneling microscope (AFM/STM). A tungsten probe tip glued onto the end of the quartz rod enables the detection of tunneling currents for STM observation. Au surface was observed in both AFM and STM modes. The resolution difference is discussed in terms of the insulating oxide layer on the tip. We also demonstrate the AFM/STM observation of the Si(111)-7×7 surface with atomic resolution in an ultrahigh vacuum.
High-power operation of electroabsorption modulators
Authors: Bian Zhixi , Christofferson James , Shakouri Ali , Kozodoy Peter
Published: October 2003

Using a thermoreflectance imaging technique, surface temperature of active electroabsorption modulators is measured at different incident powers and modulator biases. Excellent agreement is obtained between these data and the results of a self-consistent finite element model. It is shown experimentally and theoretically that thermal runaway at high-power operation can be avoided by improving the thermal design of the device. High-power operation is achieved in an optimized device structure, yielding a high, damage-free power dissipation level in excess of 300 mW.
Local anisotropy in strained manganite thin films
Authors: Souza-Neto N. M. , Ramos A. Y. , Tolentino H. C. N. , Favre-Nicolin E. , Ranno L.
Published: October 2003

We report on an angular resolved x-ray absorption spectroscopy study of the local atomic structure around the manganese ions in La0.7Sr0.3MnO3 thin films epitaxially grown on tensile and compressive substrates. Ab initio calculations provide strong support to the analysis of the experimental data and make possible the unambiguous derivation of a model of local distortion around the manganese atoms, without modification of the tilt angle Mn–O–Mn, among the octahedra. This distortion, tending to localize the charge carriers, is the driving parameter in the modifications of the magnetic and transport properties observed in thin films with respect to bulk systems.
Modelling vegetable marketing systems in South East Asia: phenomenological insights from Vietnam
Authors: Cadilhon Jean‐Joseph , Fearne Andrew P. , Moustier Paule , Poole Nigel D.
Published: October 2003

This article presents a conceptual framework for the analysis of vegetable supply chains in a South East Asian context and the role wholesale markets play in these chains. Following a review of the literature on food marketing systems in developing countries and preliminary fieldwork in South East Asia, a holistic framework is proposed, including what are perceived to be the critical factors in the development of improved fresh food marketing systems: domestic legal and policy factors, international trade policies and food markets, history, geography, and cultural and social norms. The particular role of trust and collaboration among stakeholders in the Ho Chi Minh City vegetable marketing system is highlighted.
Quality perceptions in international distribution: an empirical investigation in a complete distribution chain
Authors: Korneliussen Tor , Grønhaug Kjell
Published: October 2003

Three theory‐based hypotheses related to distribution chains and quality perceptions are advanced and examined empirically. The reported findings show that upstream channel members place more emphasis on distribution quality, while downstream channel members place more emphasis on product quality. A systematic change in quality perceptions is observed across national borders. In addition, more similar quality perceptions are observed among adjacent chain stages than those chain stages that are further apart.
Images and Policy Preferences
Authors: Schafer Mark
Published: October 2003

This article reports the results of an experiment that tests the independent and interactive effects of two dimensions of international images: perceived historial relationship and cultural differences. Priming techniques are used to manipulate images in subjects who are involved in a simulated international conflict. Dependent variables include attitudes and behaviors, the latter in the form of policy preferences arranged on a cooperative‐conflictual continuum. The results indicate that images do matter. When the perceived relationship is hostile, subjects develop more negative attitudes toward their opponents and choose more conflictual policies. Cultural differences produce more negative attitudes in all conditions but result in more negative policy selections only when the perceived relationship is hostile. In other words, in considering policy moves, cultural differences exacerbate conflict between enemies, but make no difference between friends, in spite of the negative outgroup attitudes they elicit.
Political Psychology as a Lens for Viewing Traumatic Events
Authors: Koopman Cheryl
Published: October 2003

A burgeoning area of scientific inquiry uses psychological perspectives to understand traumatic events. This research has led to the identification of psychological symptoms and disorders frequently experienced in response to traumatic events. Many of the events having traumatic effects on large numbers of persons are of interest to political psychologists. Such events include the Holocaust, war, terrorism, captivity, torture, political migration, living as a political refugee, and assassination. Some interpersonal forms of trauma, such as rape and incest, also may be viewed with a political perspective. Although a number of studies have examined psychological consequences of political events, this area of inquiry is rarely explicitly considered within the domain of political psychology. Adopting an explicitly political psychology perspective on traumatic events may enrich our interdisciplinary understanding of these events and inform the design and evaluation of intervention programs to reduce psychological distress resulting from these events.
Women and the Social Movements of the 1960s: Activists, Engaged Observers, and Nonparticipants
Authors: Stewart Abigail J. , Settles Isis H. , Winter Nicholas J. G.
Published: October 2003

Many women in the generation that attended college during the 1960s have reported that they were influenced by the social movements of that era, even women who did not participate in them. In addition to political activists, social movements also appear to include “engaged observers”—individuals who are attentive to movement writings and activities, and express moral and even financial support for them, but who take no other action. Although activism in a movement may be the best predictor of future political action, engaged observation may be related to other indicators of political socialization, such as a powerful felt impact of the movement and well‐developed political attitudes. Evidence to support this notion is drawn from studies of three samples of college‐educated white and black women.
Collective Identities of Class and Gender: Working‐Class Women in the Pittston Coal Strike
Authors: Beckwith Karen
Published: October 2003

This article investigates the intersections and tensions between two collective identities, those of class and gender, for working‐class women involved in supporting the 1989–1990 strike against Pittston Coal Group in southwestern Virginia. In the case of this year‐long (and ultimately successful) strike, women were organized by United Mine Workers of America (UMWA) staff in strike support activities, but they also sought to organize themselves as women. The tensions between their identity as members of the working class and their identity as women are revealed by examining their forms of activism, their relationship with the UMWA, the divisions between groups of activist women, and the articulation of women's involvement in the strike. The experiences of these women are briefly compared with women's activism in the 1984–1985 British Coal strike. The article concludes by arguing that collective identity is best understood as it emerges in response to specific contexts.
Saintliness and the Moral Life
Authors: Wynn Mark Robert
Published: October 2003

Drawing on the work of Raimond Gaita, the paper considers the role that may be played by the lives of the saints, both in alerting us to the moral standing of other human beings, and in helping us to articulate the concept of “humanity” understood in a morally rich sense. The paper considers whether Gaita's treatment of these themes presents something like a natural law ethic, in the sense of supplying arguments which favour broadly Christian conclusions without depending upon explicitly Christian premises. It also considers whether Gaita's view, contrary to his own belief, invites extrapolation in the direction of a more religiously engaged stance. In these ways, the paper aims to address the question of the relationship between religious and moral understanding in terms that are arguably more fruitful than those suggested by the dominant ethical theories.
Reinhold Niebuhr in Contemporary Scholarship
Authors: Lovin Robin
Published: October 2003

Recent studies of Reinhold Niebuhr's life and work demonstrate his continued importance in theology, ethics, and political thought. Historical studies by Heather Warren, Mark Kleinman, and Normunds Kamergrauzis provide new assessments of Niebuhr's role as a political and religious leader in his own time and trace the consequences of the movements in which he participated. They also show us more clearly how his work was connected to the ideas and programs of his contemporaries. Colm McKeogh offers a more systematic treatment of Niebuhr's political realism in relation to just war theory. Niebuhr's intellectual legacy remains disputed, with Stanley Hauerwas and Langdon Gilkey offering radically different assessments of his theology. Hauerwas sees in Niebuhr a close connection to the religious liberalism of William James that precludes any authentic Christian witness. Niebuhr's empiricism reduces God to a necessary feature of human consciousness. Gilkey notes Niebuhr's early use of James' psychology, but discerns a theology of history that is central to Niebuhr's mature work. In that theology, the ground of hope necessarily lies beyond human consciousness, and indeed beyond history itself.
Intransitivity and Future Generations: Debunking Parfit's Mere Addition Paradox
Authors: Chan Kai M. A.
Published: October 2003

ABSTRACT Duties to future persons contribute critically to many important contemporaneous ethical dilemmas, such as environmental protection, contraception, abortion, and population policy. Yet this area of ethics is mired in paradoxes. It appeared that any principle for dealing with future persons encountered Kavka's paradox of future individuals, Parfit's repugnant conclusion, or an indefensible asymmetry. In 1976, Singer proposed a utilitarian solution that seemed to avoid the above trio of obstacles, but Parfit so successfully demonstrated the unacceptability of this position that Singer abandoned it. Indeed, the apparently intransitivity of Singer's solution contributed to Temkin's argument that the notion of “all things considered better than” may be intransitive. In this paper, I demonstrate that a time‐extended view of Singer's solution avoids the intransitivity that allows Parfit's mere addition paradox to lead to the repugnant conclusion.

However, the heart of the mere addition paradox remains: the time‐extended view still yields intransitive judgments. I discuss a general theory for dealing with intransitivity (Transitivity by Transformation) that was inspired by Temkin's sports analogy, and demonstrate that such a solution is more palatable than Temkin suspected. When a pair‐wise comparison also requires consideration of a small number of relevant external alternatives, we can avoid intransitivity and the mere addition paradox without infinite comparisons or rejecting the Independence of Irrelevant Alternatives Principle
A machine‐order search space for job‐shop scheduling problems
Authors: Choi S. H. , Yang F. Y.
Published: October 2003

This paper proposes a methodology for real‐time job‐shop scheduling problems. It introduces a new classification of the scheduling methods for JSSPs with emphasis on the search methods and the significance of the search space. Subsequently, a machine‐order search space is proposed as a new framework in which different single‐machine scheduling algorithms and search methods can be incorporated to solve JSSPs. An optimization model relating makespan minimization and the proposed machine‐order search space is also described. The proposed methodology finds an optimal solution by searching a proper machine order in the machine‐order search space and scheduling the machines one by one in this order. Such an approach significantly reduces the size of the search space, and hence the computing efforts. As a result, scheduling of large JSSPs in real‐time becomes practicable.
An algorithm for clustering based on non‐smooth optimization techniques
Authors: Bagirov A. M. , Rubinov A. M. , Soukhoroukova N. V. , Yearwood J.
Published: October 2003

The problem of cluster analysis is formulated as a problem of non‐smooth, non‐convex optimization, and an algorithm for solving the cluster analysis problem based on non‐smooth optimization techniques is developed. We discuss applications of this algorithm in large databases. Results of numerical experiments are presented to demonstrate the effectiveness of this algorithm.
The Information Content Of Calls Of Debt: Evidence From Long‐Run Stock Returns
Authors: Affleck‐Graves John , Miller Robert E.
Published: October 2003

We examine the long‐run performance of the common stock of firms following calls of both straight and convertible debt from 1945 to 1995. Using a sample of 718 calls of straight debt, we find an average abnormal return in the five years following the call of between 0.16% and 0.34% per month, which compounds to an economically and statistically significant 11% to 22% over the five‐year period. This evidence of overperformance following calls shows a distinct symmetry between the straight debt and equity markets. Issues of debt and equity are both followed by long‐term underperformance, whereas stock repurchases and debt calls are both followed by long‐run overperformance. For our sample of 713 calls of convertible debt, we find little systematic evidence of abnormal performance following the call. Some researchers suggest that calls of convertible debt provide negative signals to the market. Our results provide no support for this claim. In contrast, our evidence of marginal positive long‐run returns provides weak support for the model that calls of convertible debt signal the realization of profitable investment options, and for the price pressure hypothesis.
A Study of Flow Theory in the Foreign Language Classroom
Authors: Egbert Joy
Published: October 2003

This article focuses on the relationship between flow experiences and language learning. Flow Theory suggests that flow experiences (characterized by a balance between challenge and skills and by a person's interest, control, and focused attention during a task) can lead to optimal learning. This theory has not yet been tested in the area of foreign or second language learning. The purpose of the present study is twofold: first, to establish the foundation for a research stream addressing flow in language learning, and second, to investigate whether flow exists in foreign language (FL) classrooms. Findings suggest that flow does exist in the FL classroom and that Flow Theory offers an interesting and useful framework for conceptualizing and evaluating language learning activities.
Discovery of Olivine in the Nili Fossae Region of Mars
Authors: Hoefen Todd M. , Clark Roger N. , Bandfield Joshua L. , Smith Michael D. , Pearl John C. , Christensen Philip R.
Published: October 2003

We have detected a 30,000-square-kilometer area rich in olivine in the Nili Fossae region of Mars. Nili Fossae has been interpreted as a complex of grabens and fractures related to the formation of the Isidis impact basin. We propose that post-impact faulting of this area has exposed subsurface layers rich in olivine. Linear mixture analysis of Thermal Emission Spectrometer spectra shows surface exposures of 30% olivine, where the composition of the olivine ranges from Fo
30
to Fo
70
.
Reverse Vaccinology and Genomics
Authors: Rappuoli Rino , Covacci Antonello
Published: October 2003

The genomic revolution has had a dramatic effect on our ability to find new vaccine targets and develop effective vaccines.
Lysostaphin Disrupts
Staphylococcus aureus
and
Staphylococcus epidermidis
Biofilms on Artificial Surfaces
Authors: Wu Julie A. , Kusuma Caroline , Mond James J. , Kokai-Kun John F.
Published: October 2003

Staphylococci often form biofilms, sessile communities of microcolonies encased in an extracellular matrix that adhere to biomedical implants or damaged tissue. Infections associated with biofilms are difficult to treat, and it is estimated that sessile bacteria in biofilms are 1,000 to 1,500 times more resistant to antibiotics than their planktonic counterparts. This antibiotic resistance of biofilms often leads to the failure of conventional antibiotic therapy and necessitates the removal of infected devices. Lysostaphin is a glycylglycine endopeptidase which specifically cleaves the pentaglycine cross bridges found in the staphylococcal peptidoglycan. Lysostaphin kills
Staphylococcus aureus
within minutes (MIC at which 90% of the strains are inhibited [MIC
90
], 0.001 to 0.064 μg/ml) and is also effective against
Staphylococcus epidermidis
at higher concentrations (MIC
90
, 12.5 to 64 μg/ml). The activity of lysostaphin against staphylococci present in biofilms compared to those of other antibiotics was, however, never explored. Surprisingly, lysostaphin not only killed
S. aureus
in biofilms but also disrupted the extracellular matrix of
S. aureus
biofilms in vitro on plastic and glass surfaces at concentrations as low as 1 μg/ml. Scanning electron microscopy confirmed that lysostaphin eradicated both the sessile cells and the extracellular matrix of the biofilm. This disruption of
S. aureus
biofilms was specific for lysostaphin-sensitive
S. aureus
, as biofilms of lysostaphin-resistant
S. aureus
were not affected. High concentrations of oxacillin (400 μg/ml), vancomycin (800 μg/ml), and clindamycin (800 μg/ml) had no effect on the established
S. aureus
biofilms in this system, even after 24 h. Higher concentrations of lysostaphin also disrupted
S. epidermidis
biofilms.
Interlaboratory Comparison of Agar Dilution and Etest Methods for Determining the MICs of Antibiotics Used in Management of
Neisseria meningitidis
Infections
Authors: Vázquez Julio A. , Arreaza Luisa , Block Colin , Ehrhard Ingrid , Gray Stephen J. , Heuberger Sigrid , Hoffmann Steen , Kriz Paula , Nicolas Pierre , Olcen Per , Skoczynska Anna , Spanjaard Lodewijk , Stefanelli Paola , Taha Muhamed-Kheir , Tzanakaki Georgina
Published: October 2003

Previous studies have shown that there is considerable variation in the methods and media used to determine the susceptibility of
Neisseria meningitidis
to antimicrobial agents in different countries. In this study, national and regional reference laboratories used a standardized methodology to determine the MICs of antibiotics used in the management of meningococcal infection. Fourteen laboratories participated in the study, determining the susceptibility to penicillin G, rifampin, cefotaxime, ceftriaxone, ciprofloxacin, and ofloxacin of a collection of 17 meningococci, of which 11 strains were previously defined as having intermediate resistance to penicillin (Pen
I
) by sequencing and restriction fragment length polymorphism analysis of the
penA
gene. The MIC was determined by agar dilution and Etest with Mueller-Hinton agar (MH), MH supplemented with sheep blood (MH+B), and MH supplemented with heated (chocolated) blood. Several laboratories encountered problems obtaining confluent growth with unsupplemented MH. MH+B was considered to give the most congruent and reproducible results among the study laboratories. The modal MIC for MH+B for each antibiotic and method was calculated to define the MIC consensus, allowing assessment of each individual laboratory's data in relation to the others. The agreement in each antibiotic/method/medium combination was defined as the percentage of laboratories with a result within one dilution of the modal result. For the whole study, an agreement of 90.6% was observed between agar dilution and Etest methods. The agreement in each laboratory/antibiotic/method combination ranged from 98.2% to 69.7%, with six laboratories demonstrating agreement higher than 90% and 11 more than 80%. The ability of the laboratories to detect the Pen
I
isolates ranged from 18.2% to 100%. The apparent difficulty in interpreting susceptibility to rifampin, particularly with the Etest method, is very interesting.
Chloramphenicol Is a Potent Inhibitor of Cytochrome P450 Isoforms CYP2C19 and CYP3A4 in Human Liver Microsomes
Authors: Park Ji-Young , Kim Kyoung-Ah , Kim Su-Lyun
Published: October 2003

The inhibitory effect of chloramphenicol on human cytochrome P450 (CYP) isoforms was evaluated with human liver microsomes and cDNA-expressed CYPs. Chloramphenicol had a potent inhibitory effect on CYP2C19-catalyzed
S
-mephytoin 4′-hydroxylation and CYP3A4-catalyzed midazolam 1-hydroxylation, with apparent 50% inhibitory concentrations (inhibitory constant [

K
i

] values are shown in parentheses) of 32.0 (7.7) and 48.1 (10.6) μM, respectively. Chloramphenicol also weakly inhibited CYP2D6, with an apparent 50% inhibitory concentration (

K
i

) of 375.9 (75.8) μM. The mechanism of the drug interaction reported between chloramphenicol and phenytoin, which results in the elevation of plasma phenytoin concentrations, is clinically assumed to result from the inhibition of CYP2C9 by chloramphenicol. However, using human liver microsomes and cDNA-expressed CYPs, we showed this interaction arises from the inhibition of CYP2C19- not CYP2C9-catalyzed phenytoin metabolism. In conclusion, inhibition of CYP2C19 and CYP3A4 is the probable mechanism by which chloramphenicol decreases the clearance of coadministered drugs, which manifests as a drug interaction with chloramphenicol.