bluuebunny/crossref_metadata_2025 huggingface dataset:
A scale to screen for DSM-IV Axis I disorders in psychiatric out-patients: performance of the Psychiatric Diagnostic Screening Questionnaire
Authors: ZIMMERMAN M. , CHELMINSKI I.
Published: July 2006

Background. The Psychiatric Diagnostic Screening Questionnaire (PDSQ) is a reliable and valid self-report scale designed to screen for the most common DSM-IV Axis I disorders encountered in out-patient mental health settings. The present report is the second large-scale validation study of the PDSQ in psychiatric out-patients. Because some of the sizes of the diagnostic groups in the initial report were modest, it is important to determine whether the recommended cut-off scores to screen for psychiatric disorders remained the same in a replication study.

Method. Six hundred and seventy psychiatric out-patients presenting for treatment were evaluated with a semi-structured diagnostic interview after completing the PDSQ.

Results. Based on receiver operating curve analysis, the PDSQ performed as well in the replication sample as in the initial validation study. For nine of the 13 PDSQ subscales the recommended cut-off score in the replication study was the same as in the initial study. After combining the data from the two studies (n=1300) the mean sensitivity across the 13 PDSQ subscales was 87% and the mean negative predictive value was 97%.

Conclusions. The PDSQ is a diagnostic aid designed to improve the efficiency of conducting initial diagnostic evaluations. From a clinical perspective it is important that a screening tool have good sensitivity so that most cases are detected, and high negative predictive value so that most non-cases on the measure are indeed non-cases. The results of this second large validation study indicate that most of the PDSQ subscales achieved this goal.
A REPRESENTATION THEOREM FOR VOTING WITH LOGICAL CONSEQUENCES
Authors: GÄRDENFORS PETER
Published: July 2006

This paper concerns voting with logical consequences, which means that anybody voting for an alternative x should vote for the logical consequences of x as well. Similarly, the social choice set is also supposed to be closed under logical consequences. The central result of the paper is that, given a set of fairly natural conditions, the only social choice functions that satisfy social logical closure are oligarchic (where a subset of the voters are decisive for the social choice). The set of conditions needed for the proof include a version of Independence of Irrelevant Alternatives that also plays a central role in Arrow's impossibility theorem.
Finding the Balance: Writing and Performing Ethics in Théâtre du Soleil’s Le Dernier Caravansérail (2003)
Authors: McEvoy William
Published: July 2006

Théâtre du Soleil’s latest production, Le Dernier Caravansérail (The Last Caravanserai), staged the stories and experiences of immigrants, refugees, and asylum-seekers from around the world. In this article, William McEvoy argues that the company was motivated both by a political agenda to make migrants more visible and a concern to investigate the ethical implications of its own creative processes. This led to a potential conflict between representing migrants directly on stage and a performance that reflected the company’s worries about turning migrants’ traumatic narratives into theatre and spectacle. Focusing on the concept of balance in the production, the article shows how Théâtre du Soleil presented the ethical negotiations between creative self and represented other through exploring the links between text and performance, writing and the body, and manipulation and resistance. William McEvoy is a lecturer in the English Department at the University of Sussex, specializing in contemporary theatre and performance. He has published work on Peter Brook and Ariane Mnouchkine, and his current research deals with the shifting role of the text in experimental and physical theatre.
Huang Zuolin: Michael Chekhov’s Link to China’s Modern Theatre
Authors: Fei Faye Chunfang
Published: July 2006

The folllowing article is a revised and edited version of a keynote address given by Faye Chunfang Fei at the Michael Chekhov Symposium, ‘Theatre of the Future?’, in November 2005 – held at Dartington Hall, where the actor and director Huang Zuolin worked under Chekhov’s guidance in 1936, an experience which helped to shape his lifelong work in uniting the best in western theatrical traditions with those of his native China. Faye Chunfang Fei traces this formative influence, along with those of Stanislavsky, of Brechtian Epic Theatre, and of traditional and modern Chinese forms, in shaping some of the major productions of probably the most influential figure in the Chinese theatre of the later twentieth century. Faye Chunfang Fei received her doctorate in Theatre Studies from the Graduate Center of City University of New York in 1991, and taught theatre in the United States for nine years before taking her present position of Professor of English and Drama at East China Normal University, Shanghai. Her publications include Chinese Theories of Theatre and Performance from Confucius to the Present (University of Michigan Press, 1999), and she is also an internationally produced playwright.
A Theatre for Cannibals: Images of Europe in Indigenous African Theatre of the Colonial Period
Authors: Irobi Esiaba
Published: July 2006

Europe’s colonial presence on the African continent from 1885 to the 1960s produced complex discourses about race and its representation. Whereas the Europeans constructed their putative images of Africans as inferior beings through radio, television, film, and print, for a predominantly literate sector, Africans deployed a more complex and mixed set of literacies. As well as conventional forms of literature, Africans used iconographic, kinaesthetic, proxemic, sonic, linguistic, tactile, calligraphic and sartorial literacies in their indigenous festivals and ritual theatres to resist, historicize, and domesticate colonial whiteness from the nineteenth century to the present day. In this article, Esiaba Irobi offers a detailed response to Bell Hooks’s observation (in Black Looks: Race and Representation, 1992) that in the work of postcolonial critics ‘there is a continued fascination with the way white minds, particularly the colonial imperialist traveller, perceive blackness, and very little expressed interest in representations of whiteness in the black imagination’. Esiaba Irobi is an Associate Professor of International Theatre at Ohio University, Athens. Born in the Republic of Biafra, he has lived in exile in Nigeria, Britain, and the USA. His African Festival and Ritual Theatre: Resisting Globalization on the Continent and Diaspora since 1492 is due for publication by Palgrave Macmillan in 2007.
STAT signalling in the heart and cardioprotection
Authors: Soond Surinder M. , Latchman David S. , Stephanou Anastasis
Published: July 2006

During the past six years, great progress has been made in defining the key cellular and molecular signalling pathways that determine the fate of cardiac myocytes after ischaemia–reperfusion (IR) and consequently the severity of myocardial infarction. Among the complex network of kinases and transcription factors that mediate signals during IR is the STAT family of ‘signal transducers and activators of transcription’. During IR they are inducibly activated by Janus kinases and have the capability of transcriptionally regulating pro-survival and apoptotic gene expression. In this review we focus on recent progress made in elucidating the regulation and role of the STAT family of proteins during cardioprotective signalling events in myocardial preconditioning and during IR injury in cardiac myocyte cells and the myocardium. Moreover, we also highlight developments in understanding how this signalling pathway might be amenable to therapeutic intervention, permitting cardiac myocyte survival following IR.
Ocean mixed layer depth: A subsurface proxy of ocean‐atmosphere variability
Authors: Lorbacher K. , Dommenget D. , Niiler P. P. , Köhl A.
Published: July 2006

A new criterion, based on the shallowest extreme curvature of near surface layer density or temperature profiles, is established for demarking the mixed layer depth, hmix. Using historical global hydrographic profile data, including conductivity‐temperature‐depth and expendable bathythermograph data obtained during World Ocean Circulation Experiment, its seasonal variability and monthly to interannual anomalies are computed. Unlike the more commonly used Δ criterion, the new criterion is able to deal with both different vertical resolutions of the data set and a large variety of observed stratification profiles. For about two thirds of the profiles our algorithm produces an hmix/c that is more reliable than the one of the Δ criterion. The uncertainty for hmix/c is ±5 m for high‐ (<5 m) and ±8 m for low‐ (<20 m) resolution profiles. A quality index, QImix, which compares the variance of a profile above hmix to the variance to a depth of 1.5 × hmix, shows that for the 70% of the profile data for which a clearly recognizable well‐mixed zone exists near the surface, our criterion identifies the depth of the well‐mixed zone in all cases. The standard deviation of anomalous monthly hmix/c is typically 20–70% of the long‐term mean hmix/c. In the tropical Pacific the monthly mean anomalies of hmix/c are not well correlated with anomalies of sea surface temperature, which indicate that a variety of turbulent processes, other than surface heat fluxes, are important in the upper ocean there. Comparisons between observed hmix/c and Massachusetts Institute of Techonology/ocean general circulation model/Estimating the Circulation and Climate of the Ocean model simulated mixed layer depth indicate that the KPP algorithm captures in general a 30% smaller mixed layer depth than observed.
Simulation study of the one‐dimensional Burridge‐Knopoff model of earthquakes
Authors: Mori Takahiro , Kawamura Hikaru
Published: July 2006

Spatiotemporal correlations of the one‐dimensional spring‐block (Burridge‐Knopoff) model of earthquakes are extensively studied by means of numerical computer simulations. Particular attention is paid to clarifying how the statistical properties of earthquakes depend on the frictional and elastic properties of earthquake faults. It is found that as the velocity‐weakening tendency of the friction force gets weaker, the system tends to be more critical, while as the velocity‐weakening tendency gets stronger, the system tends to be more off critical with enhanced features of a characteristic earthquake. The model exhibits several eminent precursory phenomena prior to the large event in its spatiotemporal correlations. Preceding the main shock, the frequency of smaller events is gradually enhanced, whereas just before the main shock, it is suppressed in a close vicinity of the epicenter of the upcoming event (the Mogi doughnut). The timescale of the onset of the doughnut‐like quiescence depends on the extent of the frictional instability. Under certain conditions, preceding the main shock, the apparent B value of the magnitude distribution increases significantly. The existence of such distinct precursory phenomena may open a way to the prediction of the time and the position of the upcoming large event.
Mechanisms of decadal variability in the shallow subtropical‐tropical circulation of the Atlantic Ocean: A model study
Authors: Hüttl Sabine , Böning Claus W.
Published: July 2006

A suite of basin‐scale models of the thermohaline and wind‐driven circulation in the Atlantic Ocean is used to study the mechanisms of decadal variability in the shallow subtropical‐tropical cells (STCs). The emphasis is on the spatial patterns of the transport anomalies in the tropical thermocline, particularly their manifestation in the equatorial current system and on the relative role of changes in the deep meridional overturning cell (MOC) associated with variations in the formation of Labrador Sea Water (LSW) in the subpolar North Atlantic. Using wind stress and heat flux variations based on NCEP/NCAR‐reanalysis products, the variability of the zonally integrated STC transports is similar to that obtained in a recent regional model study, corroborating the role of both the southern and northern STC in supporting wind‐driven transport anomalies of O(2 Sv) near the equator. Sensitivity experiments indicate that changes in subarctic MOC transports associated with the strong variability in LSW formation during the last decades contributed a signal of O(0.3 Sv) to the upper‐layer equatorial transports. Whereas the local wind‐driven variability clearly dominates on interannual‐decadal timescales and is confined to depths down to 150 m, the weak MOC‐related signal is primarily reflected in an interdecadal modulation of the STC transports. While a strong part in the STC's transport anomalies is associated with the western boundary current (NBC), there is an important contribution also by weaker, interior ocean flow anomalies which tend to counteract the variability of the NBC.
Spatial and temporal sea‐surface temperatures in the eastern equatorial Pacific over the past 150 kyr
Authors: Horikawa Keiji , Minagawa Masao , Murayama Masafumi , Kato Yoshihisa , Asahi Hirofumi
Published: July 2006

We present the new alkenone‐based sea‐surface temperature (SST) records from the eastern equatorial Pacific over the past 150 kyr. Core HY04 (4°N) at the North Equatorial Countercurrent (NECC) registered the invariant SSTs (25.8–27.2°C), whereas core HY06 (0°N) registered cyclic glacial‐interglacial SST variations (22.4–26.1°C). Although HY06 alkenone‐based SST evolution was almost consistent with the previously published SST records from around the equator, at site HY04 alkenone‐ and foraminiferal Mg/Ca‐based SSTs showed a large difference in the magnitude of LGM SST cooling. We hypothesize that alkenone‐based SSTs might not fully express the true magnitude of glacial SST cooling in the NECC, as suggested by the coincidence of higher glacial productivity and unchanged glacial SSTs at site HY04. However, further SST data in the NECC are needed before this can be accepted with any degree of confidence.
Influence of the reaction mechanism on the time course of the entropy production during reversible polymerization
Authors: Stier Ulli
Published: July 2006

The paper shows the influence of the reaction mechanism on the time course of the entropy production σ in a closed system during reversible polymerization. We consider two different reaction mechanisms with (a) being a polycondensation and (b) a chain growth mechanism. For both mechanisms explicit expressions for the entropy production σ as a function of time t are derived. To demonstrate the application of these general expressions we consider two different polymerization experiments where the reaction starts (i) from monomer molecules polymerizing to a defined number average chain length x¯n,eq and (ii) from monodisperse polymer molecules reacting with each other under the constraint that x¯n is the same at the beginning and the end of the reaction. In both cases we treat the system to be ideal and describe the kinetics of the reversible polymerization reactions using two kinetic constants for the forward and backward reactions, respectively. Under these assumptions the difference in the curvature of the entropy production σ between a polycondensation and a chain growth mechanism is only marginal if the reaction starts from monomer molecules polymerizing to a defined number average chain length x¯n,eq.
Calculation of the entropy and free energy of peptides by molecular dynamics simulations using the hypothetical scanning molecular dynamics method
Authors: Cheluvaraja Srinath , Meirovitch Hagai
Published: July 2006

Hypothetical scanning (HS) is a method for calculating the absolute entropy S and free energy F from a sample generated by any simulation technique. With this approach each sample configuration is reconstructed with the help of transition probabilities (TPs) and their product leads to the configuration’s probability, hence to the entropy. Recently a new way for calculating the TPs by Monte Carlo (MC) simulations has been suggested, where all system interactions are taken into account. Therefore, this method—called HSMC—is in principle exact where the only approximation is due to insufficient sampling. HSMC has been applied very successfully to liquid argon, TIP3P water, self-avoiding walks on a lattice, and peptides. Because molecular dynamics (MD) is considered to be significantly more efficient than MC for a compact polymer chain, in this paper HSMC is extended to MD simulations as applied to peptides. Like before, we study decaglycine in vacuum but for the first time also a peptide with side chains, (Val)2(Gly)6(Val)2. The transition from MC to MD requires implementing essential changes in the reconstruction process of HSMD. Results are calculated for three microstates, helix, extended, and hairpin. HSMD leads to very stable differences in entropy TΔS between these microstates with small errors of 0.1–0.2kcal∕mol (T=100K) for a wide range of calculation parameters with extremely high efficiency. Various aspects of HSMD and plans for future work are discussed.
Complex chemical kinetics in single enzyme molecules: Kramers’s model with fractional Gaussian noise
Authors: Chaudhury Srabanti , Cherayil Binny J.
Published: July 2006

A model of barrier crossing dynamics governed by fractional Gaussian noise and the generalized Langevin equation is used to study the reaction kinetics of single enzymes subject to conformational fluctuations. The direct application of Kramers’s flux-over-population method to this model yields analytic expressions for the time-dependent transmission coefficient and the distribution of waiting times for barrier crossing. These expressions are found to reproduce the observed trends in recent simulations and experiments.
Poincaré-Birkhoff periodic orbits for mechanical Hamiltonian systems on T*Tn
Authors: Bernardi Olga , Cardin Franco
Published: July 2006

Here, a version of the Arnol’d conjecture, first studied by Conley and Zehnder, giving a generalization of the Poincaré-Birkhoff last geometrical theorem, is proved inside Viterbo’s framework of the generating functions quadratic at infinity. We give brief overviews of some tools that are often utilized in symplectic topology.
Host-assisted intramolecular vibrational relaxation at low temperatures: OH in an argon cage
Authors: Shin H. K.
Published: July 2006

The vibrational relaxation of hydroxyl radicals in the AΣ+2 (v=1) state has been studied using the semiclassical perturbation treatment at cryogenic temperatures. The radical is considered to be trapped in a closest packed cage composed of the 12 nearest argon atoms and undergoes local translation and hindered rotation around the cage center. The primary relaxation pathway is towards local translation, followed by energy transfer to rotation through hindered-to-free rotational transitions. Free-to-free rotational transitions are found to be unimportant. All pathways are accompanied by the propagation of energy to argon phonon modes. The deexcitation probability of OH(v=1) is 1.3×10−7 and the rate constant is 4.7×105s−1 between 4 and 10K. The negligible temperature dependence is attributed to the presence of intermolecular attraction (⪢kT) in the guest-host encounter, which counteracts the T2 dependence resulting from local translation. Calculated relaxation time scales are much shorter than those of homonuclear molecules, suggesting the importance of the hindered and free motions of OH and strong guest-host interactions.
Effect of static and dynamic disorder on exciton mobility in oligothiophenes
Authors: Raimondo L. , Laicini M. , Spearman P. , Tavazzi S. , Borghesi A.
Published: July 2006

The polarized optical absorption spectra of different quaterthiophene single crystals in the energy region of the exciton bands originating from the first molecular transition are reported as measured in the temperatures ranging from 7to140K. The intrinsic higher mobility of the b-polarized 0-0 au exciton both with respect to its replicas and to the a-polarized structures is demonstrated in high quality crystals at the lowest temperatures. The influence of structural disorder on mobility is discussed considering, for the different samples, the measured lineshape and linewidth of the absorption peaks, and the relative lineshift and intensity ratio between the 0-0 au line and its first replica at the lowest temperature. The influence of dynamic disorder is discussed considering the lineshape and linewidth of the measured peaks as a function of temperature for both polarizations in the framework of the exciton-phonon coupling theory.
Electron acoustic solitons in a relativistic plasma with nonthermal electrons
Authors: Sahu Biswajit , Roychoudhury Rajkumar
Published: July 2006

Electron acoustic solitary waves (EASWs) are studied using Sagdeev’s pseudopotential technique for a plasma comprising relativistic ions, cold relativistic electrons, and nonthermal hot electrons. The parametric range considered here is valid for the auroral zone. It is found that the present plasma model supports EASWs having negative potential. It is seen that the relativistic effect significantly restricts the region of existence for solitary waves. The region of existence of solitary waves also depends crucially on α, the parameter that determines the population of the energetic nonthermal electrons. For example, for α>0.18 with the soliton velocity 1.05 and u0c∕c=0.001, solitary wave solutions will not exist. We also find that for small values of α, solitary waves would exist for V<1.
A hypothesis of inductive drive to explain the sawtooth measurements of tokamak experiment for technology oriented research (TEXTOR)
Authors: Chu T. K.
Published: July 2006

A hypothesis, based on the current density profile determined from the principle of minimum dissipation of magnetic energy, is applied to explain the measurement of q(0) and current variation in a sawtooth cycle in tokomak experiment for technology oriented research (TEXTOR) [Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1985), Vol. I, p. 193]. A sawtooth oscillation is triggered when the on-axis current density in a configuration with m=0 and n=0 symmetry is driven inductively to a limit.
Auroral hot-ion dynamo model with finite gyroradii
Authors: Lennartsson O. W.
Published: July 2006

Discrete auroras have (1) narrow size s≲30km in at least one dimension (e.g., north-south) and (2) often rapid variation of forms, especially where the size is extremely small, s⩽1km. These points mesh with spatial and temporal features observed at several Earth radii in earthward flows (bursts) of hot plasma along high-latitude geomagnetic field lines. The flows (include PSBL) usually have some filamentary structure with transverse widths of a few local gyroradii of the hot protons (kT∼1–30keV), i.e., widths that encompass auroral-arc size when scaled by magnetic field-line separation. At these widths, modest density gradients (δn∼0.01–0.1cm−3) lead to charge separation by differential mirroring of hot protons and electrons and large perpendicular electric fields. Thermal escape of ionspheric electrons into positive charge layer builds up magnetic field-aligned potential difference that accelerates hot electrons from negative charge layer into the ionosphere within auroral arc thickness. As a corollary, the model delineates a mechanism for charge-driven plasma instabilities.
In situ pendeoepitaxy of GaN using heteroepitaxial AlGaN∕GaN cracks
Authors: Moon Y. T. , Liu C. , Xie J. , Ni X. , Fu Y. , Morkoç H. , Zhou Lin , Smith David J.
Published: July 2006

Pendeoepitaxy on patterned templates has been proven to be efficient for reducing threading dislocation densities in GaN thin films. In this letter, we report on in situ crack-assisted pendeoepitaxy of GaN using spontaneously formed cracks in AlGaN∕GaN heterostructures. Our approach involves the growth of an AlGaN∕GaN template followed by in situ thermal etching and deposition of an amorphous silicon nitride mask in a low pressure metal organic chemical vapor deposition system. Microwirelike GaN seeds are then formed along the crack lines during the initial stage of GaN overgrowth, which act as nucleation stripes for epitaxial lateral overgrowth. Transmission electron microscopy revealed that the lateral overgrowth of the wirelike GaN seeds effectively bends threading dislocations toward ⟨11¯00⟩ directions on the amorphous silicon nitride mask. The threading dislocation density by this method has been reduced from 2×109cm−2 in control samples to 2×108cm−2 in some parts and 5×107cm−2 in other parts of the GaN layer as determined by plan-view transmission electron microscopy which is very encouraging.
Stark-shift microscopy of single emitters
Authors: Karotke S. , Lieb A. , Hecht B.
Published: July 2006

We study the interaction of a biased, metallized tip in close proximity to single fluorescent molecules at cryogenic temperature. By scanning over the sample, the tip’s inhomogeneous electric field induces Stark shifts of the zero-phonon lines of nearby molecules. When illuminated with an off-resonant laser, molecules are tuned into resonance for specific tip positions located on circular patterns around the molecules’ spatial positions. The origins of circles belonging to different molecules can be determined with high precision. We demonstrate a spatial resolution of neighboring individual molecules of ∼50nm using a tip scanned in a distance of ∼3μm above the sample.
Generation of white light from optically pumped gallium nitride epilayers
Authors: Rahman Faiz , Johnson Nigel P.
Published: July 2006

We describe results of optical pumping experiments on gallium nitride (GaN) epilayers grown on sapphire and capped with a layer of aluminum gallium nitride (AlGaN). Our samples show the well-known yellow luminescence (in response to exposure with ultraviolet radiation) that derives from transitions to and from defect-induced gap states. We show that it is possible to enhance this downconversion luminescence by subjecting samples to mechanical stress through ultrasonic wave propagation. When double pumped with both ultraviolet and visible blue radiations, the samples generate broadband visible radiation that appears white to the human eye.
Subnanosecond piezoelectric x-ray switch
Authors: Grigoriev Alexei , Do Dal-Hyun , Kim Dong Min , Eom Chang-Beom , Evans Paul G. , Adams Bernhard , Dufresne Eric M.
Published: July 2006

We report an ultrafast piezoelectric switch for synchrotron x rays. A thin epitaxial film of piezoelectric Pb(Zr,Ti)O3 works as a diffractive optical switch at frequencies from dc to >1GHz. The broad frequency range allows single bunches of synchrotron x rays to be selected in an arbitrary sequence. The piezoelectric effect introduces mechanical strains of a fraction of 1% in the Pb(Zr,Ti)O3 film, which can be used for blocking or passing diffracted x rays.
Design, fabrication, installation, and testing of high energy sweeper
Authors: Ghosh S. , Sarkar A. , Sonti S. S. K. , Rao S. , Sivakumar V. V. , Rai A. , Barua P. , Datta S. K. , Bhowmik R. K. , Roy A.
Published: July 2006

A room temperature high-energy sweeper had been designed, fabricated, and installed at the postacceleration section of the Tandem accelerator. The sweeper, a part of the new pulsing system, is being used to inject the bunched beam without dark current into the linear accelerator acting as a booster of the Tandem. The resonance frequency of the sweeper was set at 6.0625MHz and a quality factor of ∼1300 was achieved. During off-line testing of the sweeper, a deflector voltage of ∼30kV had been measured for an input power of 300W. A pair of indigenously fabricated capacitors is used for fine-tuning of the resonance frequency. The silver plated coil of the tank circuit was fabricated with two concentric copper tubes. During the successful beam test of the sweeper, a peak to dark current ratio of 97% has been achieved.
Backward beam fanning in organic photorefractive devices
Authors: Kwon O-Pil , Jazbinsek Mojca , Günter Peter , Lee Suck-Hyun
Published: July 2006

We observe strong beam depletion of about 30% at small incident angles in layered photorefractive polymers at an electric field of −50V∕μm and an intensity of 0.3W∕cm2. At normal incidence this depletion occurs only with negative electric field directions. For positive fields, depletion occurs only in the tilted geometry and is due to forward beam fanning, as previously observed. We attribute the depletion for negative electric fields mainly to the backward beam fanning as a consequence of the relatively high beam coupling efficiency in reflection grating geometries.
Self-exciting, self-sensing PbZr0.53Ti0.47O3∕SiO2 piezoelectric microcantilevers with femtogram/Hertz sensitivity
Authors: Shen Zuyan , Shih Wan Y. , Shih Wei-Heng
Published: July 2006

Piezoelectric microcantilever sensors (PEMSs) consisting of a piezoelectric layer bonded to a nonpiezoelectric layer offer the advantages of electrical self-actuation and self-detection. Here we report PEMSs 60–300μm in length fabricated from 1.5-μm-thick sol-gel PbZr0.53Ti0.47O3 (PZT) films with a 2μm grain size, a dielectric constant of 1600, and a saturation polarization of 55±5μC∕cm2. The PEMSs exhibited up to four resonance peaks with quality factors Q ranging from 120 to 320. In humidity sensing tests, a PEMS with a 60×25μm PZT∕SiO2 section and a 24×20μm SiO2 extension exhibited 1×10−15g∕Hz mass sensitivity, two orders of magnitude better than the sensitivity of the current PZT PEMS.
Huge nonequilibrium magnetoresistance in hybrid superconducting spin valves
Authors: Giazotto Francesco , Taddei Fabio , Fazio Rosario , Beltram Fabio
Published: July 2006

A hybrid ferromagnet-superconductor spin valve is proposed. Its operation relies on the interplay between nonequilibrium transport and proximity-induced exchange coupling in superconductors. Huge tunnel magnetoresistance values as large as ∼106% can be achieved in suitable ferromagnet-superconductor combinations under proper voltage biasing. The controllable spin-filter nature of the structure combined with its intrinsic simplicity makes this setup attractive for low-temperature spintronic applications where reduced power dissipation is an additional requirement.
Passive low pass filtering effect of mechanical vibrations by a granular bed composed of microglass beads
Authors: Yoon Sang-Hee , Kim Ki Lyug
Published: July 2006

Passive low pass filtering characteristics of a granular bed composed of microglass beads (MGBs) are investigated for military applications to a shock isolator. The granular bed attenuates the transmission of vibrations over a given frequency range sensitive to electronic devices through kinetic energy absorption like low pass filters in electric system. The experimental studies on five kinds of MGB with different diameters demonstrate that the cutoff frequency and the steepness of rolloff of the granular bed are inversely proportional to the diameter of MGB, and the vibration absorptivity is proportional to the diameter of MGB. The granular bed composed of 68μm diameter MGB absorbs incident mechanical vibrations with the cutoff frequency of 16.0±1.5kHz, the vibration absorptivity of 0.22, and the stopband transmittance of 1%–10%.
Coupled-wave model for square-lattice two-dimensional photonic crystal with transverse-electric-like mode
Authors: Sakai Kyosuke , Miyai Eiji , Noda Susumu
Published: July 2006

We propose a coupled-wave model for a square-lattice two-dimensional (2D) photonic crystal (PC) with a transverse electric mode. A set of coupled-wave equations is obtained from this model and it is shown that 2D optical coupling occurs between four light waves propagating in the Γ-X direction via higher-order waves propagating in the Γ-M direction. The expressions for the resonant mode frequencies derived from the coupled-wave equations describe the characteristics of experimental results for the band-edge frequencies of the 2D PC laser.
Efficient 1.54μm light emitting diode with nanometer thick polycrystalline Si anode and organic sandwich structure
Authors: Zhao W. Q. , Ran G. Z. , Ma G. L. , Xu W. J. , Dai L. , Liu W. M. , Wang P. F. , Qin G. G.
Published: July 2006

This letter reports that the 1.54μm electroluminescence efficiency of the organic light emitting diode (OLED) with a structure of nanometer thick polycrystalline silicon (NTPS)/NPB/ErQ/AlQ/Al is two orders of magnitude higher than that of the OLED with a structure of thick crystalline silicon/NPB/ErQ/Al, which is similar to the OLED reported in literature [Curry et al., Appl. Phys. Lett. 77, 2271 (2000)]. Such an improvement is mainly attributed to the fact that hole injection is controlled by NTPS anode and holes are blocked by AlQ to match electron injection, and a higher light out coupling as well.
Double-injector source of spin polarized current with controllable polarization
Authors: Zou J. , Sosnin I. , Petrashov V. T.
Published: July 2006

We present low-temperature measurements of Co∕Al spin valves with a double-injector source of spin polarized current. Using an in-plane magnetic field, the injector electrodes were magnetized in opposite directions. The spin polarization of the injected current was controlled by changing the ratio of currents through the two electrodes and was continuously varied from zero up to the maximum spin polarization of Co. This result was verified by measuring the spin valve signal, using the detector electrode magnetized to align with one of the injectors. This source can be used for spintronic applications as well as in research on hybrid ferromagnet/superconductor structures.
Uniaxial-stress effects on electronic properties of silicon carbide nanowires
Authors: Yan Binghai , Zhou Gang , Duan Wenhui , Wu Jian , Gu Bing-Lin
Published: July 2006

First-principles calculations are performed to study the mechanical properties, electronic structure, and uniaxial-stress effects of β-SiC nanowires (NWs). It is found that the band gap of SiC NWs becomes larger as their diameter decreases because of the quantum confinement effect, but increases (decreases) slightly with increasing tensile (compressive) stress up to about 12GPa. The calculated Young’s modulus and tensile strength of SiC NWs are about 620 and 52GPa, respectively, in accordance with the experimental data. The characteristics of their mechanical and electronic properties suggest that β-SiC NWs may be used in electronic composites as reinforcement nanomaterials or in nanoscale electronic/photoelectric devices under harsh environments.
Electrical transport through individual nanowires with transverse grain boundaries
Authors: Xue X. Y. , Feng P. , Wang C. , Chen Y. J. , Wang Y. G. , Wang T. H.
Published: July 2006

V 2 O 4 ∙ 0.25 H 2 O nanowires are synthesized via hydrothermal route. The nanowires are of metastable phase, and transverse grain boundaries are observed in their microstructures. Transport through individual V2O4∙0.25H2O nanowires shows nonlinear current-voltage (I-V) characteristics in the bias range of −3to3V. The resistance rapidly decreases from 2.54to0.5MΩ as the bias is raised from 0to1V. Such behaviors can be attributed to the presence of the barrier at the transverse grain boundary. By analyzing the I-V curves at various temperatures, the effective barrier height is estimated to be about 0.13eV. Our results provide important information about how the microstructure mismatch affects the electrical properties.
Rheology of complex fluids by particle image velocimetry in microchannels
Authors: Degré Guillaume , Joseph Pierre , Tabeling Patrick , Lerouge Sandra , Cloitre Michel , Ajdari Armand
Published: July 2006

We image the flow of complex fluids in microchannels of controlled geometry using tracers. The spatial resolution allows us to access quantitatively the bulk nonlinear rheology and wall slip, as we show on model polymer solutions. In perspective this strategy should prove useful for the study of heterogeneous flows of more complex fluids.
Si-based Coulomb blockade device for spin qubit logic gate
Authors: Lee S. D. , Shin S. J. , Choi S. J. , Lee J. J. , Choi J. B. , Park S. , Eric Yang S.-R. , Lee S. J. , Zyung T. H.
Published: July 2006

A lateral gate-controlled double dot structure in Si has been fabricated for studying coupled two qubits. Nonequilibrium single-electron tunneling measurements at 1.4K show that the second Coulomb peak, associated with a two-electron occupation, splits into two side peaks, and that their separation displays a strong magnetic-field dependence for various interdot coupling constants. Moreover, for some fixed magnetic fields, the separation of the side peaks decays exponentially as a function of the interdot coupling. We attribute this behavior to electron spin exchange and spin swapping between singlet and triplet states in the coupled double dot in the presence of a magnetic field.
Institutional Reform in the Provision of Public Services in Hong Kong: An Efficiency Evaluation
Authors: Walker Richard M , Li Ling Hin
Published: July 2006

Although efficiency theories have been adopted by governments around the world to improve public services, Hong Kong escaped their prescriptions until recently. In order to evaluate why such policies have been adopted, the authors develop a theory-led evaluation in which public choice theory and transaction-costs economics are synthesised to present a contingent efficiency framework. The study is focused upon the housing, planning, and lands arena, and includes analysis of policy documents and interviews with a range of civil servant, politicians, professional bodies, and private sector providers. The findings indicate that efficiency theories now explain institutional reform in Hong Kong—the variables of competition, size, asset specificity, monopoly, and change in public officials, together with the context within which public organisations in Hong Kong work, explain why such policies have now been pursued.
A
Porphyromonas gingivalis
haloacid dehalogenase family phosphatase interacts with human phosphoproteins and is important for invasion
Authors: Tribble Gena D. , Mao Song , James Chloe E. , Lamont Richard J.
Published: July 2006

Haloacid dehalogenase (HAD) family phosphatases are widespread in prokaryotes and are generally involved in metabolic processes.
Porphyromonas gingivalis
, an invasive periodontal pathogen, secretes the HAD family phosphoserine phosphatase SerB653 when in contact with gingival epithelial cells. Here we characterize the structure and enzymatic activity of SerB653 and show that a SerB653 allelic replacement mutant of
P. gingivalis
is deficient in internalization and persistence in gingival epithelial cells. In contrast, mutation of a second HAD family serine phosphatase of
P. gingivalis
(SerB1170), or of a serine transporter, did not affect invasion. A pull-down assay identified GAPDH and heat-shock protein 90 as potential substrates for SerB653. Furthermore, exogenous phosphatase regulated microtubule dynamics in host cells. These data indicate that
P. gingivalis
has adapted a formerly metabolic enzyme to facilitate entry into host cells by modulating host cytoskeletal architecture. Our findings define a virulence-related role of a HAD family phosphatase and reveal an invasin of an important periodontal pathogen.
The active metabolite of Clopidogrel disrupts P2Y12 receptor oligomers and partitions them out of lipid rafts
Authors: Savi Pierre , Zachayus Jean-Luc , Delesque-Touchard Nathalie , Labouret Catherine , Hervé Caroline , Uzabiaga Marie-Françoise , Pereillo Jean-Marie , Culouscou Jean-Michel , Bono Françoise , Ferrara Pascual , Herbert Jean-Marc
Published: July 2006

P2Y12, a G protein-coupled receptor that plays a central role in platelet activation has been recently identified as the receptor targeted by the antithrombotic drug, clopidogrel. In this study, we further deciphered the mechanism of action of clopidogrel and of its active metabolite (Act-Met) on P2Y12 receptors. Using biochemical approaches, we demonstrated the existence of homooligomeric complexes of P2Y12 receptors at the surface of mammalian cells and in freshly isolated platelets.
In vitro
treatment with Act-Met or
in vivo
oral administration to rats with clopidogrel induced the breakdown of these oligomers into dimeric and monomeric entities in P2Y12 expressing HEK293 and platelets respectively. In addition, we showed the predominant association of P2Y12 oligomers to cell membrane lipid rafts and the partitioning of P2Y12 out of rafts in response to clopidogrel and Act-Met. The raft-associated P2Y12 oligomers represented the functional form of the receptor, as demonstrated by binding and signal transduction studies. Finally, using a series of receptors individually mutated at each cysteine residue and a chimeric P2Y12/P2Y13 receptor, we pointed out the involvement of cysteine 97 within the first extracellular loop of P2Y12 in the mechanism of action of Act-Met.
Cytotoxic T lymphocytes kill multiple targets simultaneously via spatiotemporal uncoupling of lytic and stimulatory synapses
Authors: Wiedemann Aurelie , Depoil David , Faroudi Mustapha , Valitutti Salvatore
Published: July 2006

A longstanding paradox in the activation of cytotoxic T lymphocytes (CTL) arises from the observation that CTL recognize and rapidly destroy target cells with exquisite sensitivity despite the fact that cytokine production requires sustained signaling at the immunological synapse. Here we solve this paradox by showing that CTL establish sustained synapses with targets offering strong antigenic stimuli and that these synapses persist after target cell death. Simultaneously, CTL polarize lytic granules toward different cells without discrimination regarding antigenic potential. Our results show that spatiotemporal uncoupling of immunological synapse and lytic granule secretion allows multiple killing and sustained signaling by individual CTL. This unique mechanism of responding to multiple contacts provides remarkable efficiency to CTL function.
A subset of
Arabidopsis
AP2 transcription factors mediates cytokinin responses in concert with a two-component pathway
Authors: Rashotte Aaron M. , Mason Michael G. , Hutchison Claire E. , Ferreira Fernando J. , Schaller G. Eric , Kieber Joseph J.
Published: July 2006

The plant hormone cytokinin regulates numerous growth and developmental processes. A signal transduction pathway for cytokinin has been elucidated that is similar to bacterial two-component phosphorelays. In
Arabidopsis
, this pathway is comprised of receptors that are similar to sensor histidine kinases, histidine-containing phosphotransfer proteins, and response regulators (ARRs). There are two classes of response regulators, the type-A ARRs, which act as negative regulators of cytokinin responses, and the type-B ARRs, which are transcription factors that play a positive role in mediating cytokinin-regulated gene expression. Here we show that several closely related members of the
Arabidopsis
AP2 gene family of unknown function are transcriptionally up-regulated by cytokinin through this pathway, and we have designated these AP2 genes
CYTOKININ RESPONSE FACTORS
(
CRFs
). In addition to their transcriptional regulation by cytokinin, the CRF proteins rapidly accumulate in the nucleus in response to cytokinin, and this relocalization depends on the histidine kinases and the downstream histidine-containing phosphotransfer proteins, but is independent of the ARRs. Analysis of loss-of-function mutations reveals that the CRFs function redundantly to regulate the development of embryos, cotyledons, and leaves. Furthermore, the CRFs mediate a large fraction of the transcriptional response to cytokinin, affecting a set of cytokinin-responsive genes that largely overlaps with type-B ARR targets. These results indicate that the CRF proteins function in tandem with the type-B ARRs to mediate the initial cytokinin response. Thus, the evolutionarily ancient two-component system that is used by cytokinin branches to incorporate a unique family of plant-specific transcription factors.
Shape-persistent macrocyclic aromatic tetrasulfonamides: Molecules with nanosized cavities and their nanotubular assemblies in solid state
Authors: He Lan , An Yu , Yuan Lihua , Feng Wen , Li Minfeng , Zhang Dechun , Yamato Kazuhiro , Zheng Chong , Zeng Xiao Cheng , Gong Bing
Published: July 2006

Alkoxy side-chain-flanked diarylsulfonamide serves as a reliable structural motif for constructing macrocyclic aromatic tetrasulfonamides. This 90° structural motif is persistent both in solution and in the solid state, which allows the one-step formation of tetrasulfonamide macrocycles. These macrocycles adopt a cone-shaped conformation in solution and in the solid state. For each molecule, an interior cavity surrounded by the aromatic residues is formed. The cavity sizes of the macrocycles can be tuned by incorporating aromatic residues of proper sizes. Guest (solvent) molecules are found in the cavities and bound by side chains. In solution,
1
H NMR shows that the cone conformations undergo rapid interconversion at room temperature. The alkoxy side chains are found to be indispensable for maintaining the cone conformation. In addition, these porous molecules self-assemble into hollow tubular structures in the solid state. A variety of host molecules and building blocks for constructing nanoporous solid-state structures can be expected from these molecules.
The NF-κB regulator Bcl-3 and the BH3-only proteins Bim and Puma control the death of activated T cells
Authors: Bauer Anette , Villunger Andreas , Labi Verena , Fischer Silke F. , Strasser Andreas , Wagner Hermann , Schmid Roland M. , Häcker Georg
Published: July 2006

Apoptosis of activated T cells is critical for the termination of immune responses. Here we show that adjuvant-stimulated dendritic cells secrete cytokines that prime activated T cells for survival and analyze the roles of the NF-κB regulator Bcl-3 and the proapoptotic Bcl-2 family members Bim and Puma. Bcl-3 overexpression increased survival, and activated
bcl-3
−/−
T cells died abnormally rapidly. Cytokines from adjuvant-stimulated dendritic cells induced Bcl-3, but survival through cytokine priming was Bcl-3-independent. Apoptosis inhibition by Bcl-3 involved blockade of Bim activation, because Bim was overactivated in Bcl-3-deficient cells, and Bcl-3 failed to increase survival of
bim
−/−
T cells. However, adjuvants increased survival also in Bim-deficient T cells. This Bim-independent death pathway is at least in part regulated by Puma, as shown by analysis of puma
−/−
and noxa
−/−
T cells. IL-1, IL-7, and IL-15 primed T cells for survival even in the absence of Bim or Puma. Our data define interrelations and a Bim-independent pathway to activated T cell death.