bluuebunny/crossref_metadata_2025 huggingface dataset:
Decline and Recovery of the Island Fox
Authors: Coonan Timothy J. , Schwemm Catherin A. , Garcelon David K.
Published: October 2010

Native only to the California Channel Islands, the island fox is the smallest canid in North America. Populations on four of the islands were threatened to extinction in the 1990s due to human-mediated predation and disease. This is the first account of the natural history and ecology of the island fox, illustrating both the vulnerability of island ecosystems and the efficacy of cooperative conservation measures. It explains in detail the intense conservation actions required to recover fox populations, such as captive breeding and reintroduction, and large-scale ecosystem manipulation. These actions were successful due in large part to extraordinary collaboration among the scientists, managers and public advocates involved in the recovery effort. The book also examines the role of some aspects of island fox biology, characteristic of the 'island syndrome', in facilitating their recovery, including high productivity and an apparent adaptation to periodic genetic bottlenecks.
The Cambridge Economic History of Modern Europe
Authors: Broadberry Stephen , O'Rourke Kevin H.
Published: October 2010

Unlike most existing textbooks on the economic history of modern Europe, which offer a country-by-country approach, The Cambridge Economic History of Modern Europe rethinks Europe's economic history since 1700 as unified and pan-European, with the material organized by topic rather than by country. This second volume tracks Europe's economic history through three major phases since 1870. The first phase was an age of globalization and of European economic and political dominance that lasted until the First World War. The second, from 1914 to 1945, was one of war, deglobalization, and depression and the third was one of growing integration not only within Europe but also between Europe and the global economy. Leading authors offer comprehensive and accessible introductions to these patterns of globalization and deglobalization as well as to key themes in modern economic history such as economic growth, business cycles, sectoral developments, and population and living standards.
Fusion yield: Guderley model and Tsallis statistics
Authors: HAUBOLD H. J. , KUMAR D.
Published: October 2010

The reaction rate probability integral is extended from Maxwell–Boltzmann approach to a more general approach by using the pathway model introduced by Mathai in 2005 (A pathway to matrix-variate gamma and normal densities.Linear Algebr. Appl.396, 317–328). The extended thermonuclear reaction rate is obtained in the closed form via a Meijer'sG-function and the so-obtainedG-function is represented as a solution of a homogeneous linear differential equation. A physical model for the hydrodynamical process in a fusion plasma-compressed and laser-driven spherical shock wave is used for evaluating the fusion energy integral by integrating the extended thermonuclear reaction rate integral over the temperature. The result obtained is compared with the standard fusion yield obtained by Haubold and John in 1981 (Analytical representation of the thermonuclear reaction rate and fusion energy production in a spherical plasma shock wave.Plasma Phys.23, 399–411). An interpretation for the pathway parameter is also given.
Excavating sponges from the Adriatic Sea: description ofCliona adriaticasp. nov. (Demospongiae: Clionaidae) and estimation of its boring activity
Authors: Calcinai B. , Bavestrello G. , Cuttone G. , Cerrano C.
Published: October 2010

Boring sponge diversity in the area of the Conero Promontory, the most important rocky emergence on the west coast of the Adriatic Sea (Italy), was assessed. Four species were recorded; one of them,Cliona adriatica, is new and is described here. The new species differs from all the other excavating sponge species, characterized by yellow papillae and lacking or scarcity of microscleres, in the large size of the boring chambers and the presence of numerous styles.Cliona adriaticais present on about 12% of the surface of rocky bottoms in the Conero Promontory area. The impact of this highly destructive species on the carbonatic micritic rock of the promontory was evaluated calculating a relationship between the volume of the boring chambers and the surface of the epilithic portions. Consequently, it was estimated that 1 cm2of epilithic tissue corresponds to 8.5 g of excavated rock. The recorded correlation between the excavated volume and the area of the papillar zone (roughly the area of the substratum affected by the erosion) allows an estimation of the substratum removed by a boring sponge, using only visually oriented, non-destructive, sampling methods.
A Transnational Community of Scholars: The Theatre Historiography Working Group in IFTR/FIRT
Authors: POSTLEWAIT THOMAS , MICHIELI BARBARA SUŠEC
Published: October 2010

The history of the Theatre Historiography Working Group in IFTR/FIRT provides a case study of how and why the Federation has been transformed by its working groups during the last two decades. Founded in 1992, the historiography group has developed into one of the largest and most active in IFTR/FIRT. Over the last nineteen years, the members of the group, drawn from many of the countries in the Federation, have used the annual meetings to develop a diverse and often challenging scholarship on the history of theatre (broadly defined). By focusing on the basic issues in historiography, the participating scholars have refined their research and writing methods. Moreover, the essays and books, published in several languages, have contributed to major transformations in the methods and topics in performance history. The working group, besides serving as a transnational community for historical scholarship, has also contributed to revisionist methods in the teaching of theatre history in dozens of countries, especially during the last decade.
IFTR's Arabic Theatre Working Group
Authors: AMINE KHALID , AZMY HAZEM , CARLSON MARVIN
Published: October 2010

This collaborative article looks at the establishment in 2006 of an IFTR/FIRT working group in Arabic theatre, and the significance of this in terms of breaking the twentieth-century, hegemonic hold of European and North American subjects in theatre research. We trace the development of the working group from preliminary conferences and gatherings outside IFTR to its set-up and organization within the Federation. Surveying our methodologies, key issues, research areas and future directions, we argue the significance of the group's work in creating a research forum for Arab theatre scholarship.
The future possibilities of inter-Asian theatre research
Authors: NAGATA YASUSHI
Published: October 2010

Looking to the future, it is my view that Japanese theatre research needs to concentrate its efforts on scholarly exchanges with research communities in other Asian countries or cities.
The Unwritten Law of Executive Justice: Pardoning Patricide in Reconstruction-era New York
Authors: Strange Carolyn
Published: October 2010

Reconstruction was an uncertain time in New York City, the nation's foremost metropolis, riddled with political corruption and rocked by popular protest. Stabilizing efforts took numerous forms, including the brutal suppression of workers' rallies and the prosecution of municipal politicians and officials. Public faith in the criminal justice system and its capacity to prosecute and punish criminals had also reached a low ebb by the 1870s, prompting the state government to investigate the district attorney's office in New York County and its court system. In the words of a veteran member of the city's criminal bar, the “deplorable uncertainty” of punishment was making “a mockery of justice.” A Columbia University medico-legal expert agreed, claiming that murder, “if not yet cultivated as one of the fine arts … [was] a matter of daily occurrence.” High-profile trials in the wake of the Civil War tested public and professional criticism of jury independence, particularly jurors' disinclination to find killers guilty of murder, compounded by defense attorneys' growing use of “moral” and “emotional insanity” defenses. Every time apparently sane killers, such as William McFarland (tried and acquitted on grounds of “temporary insanity” in 1870 for the murder of his former wife's lover) escaped conviction on the basis of questionable insanity defenses, newspapers announced “the insanity dodge,” and medico-legal experts squabbled over the growing problem of “feigned insanity.” Occasionally Manhattan's murderers did face the gallows, especially the poor and friendless, as the execution of William Foster in March 1873 confirmed, but it seemed that well-financed and well-defended murderers, like Edward Stokes, murderer of financier Jim Fisk, could exploit the technicalities of the law if the vagaries of medicine failed to secure acquittals. A justice system of this sorry character had little hope of deterring would-be murderers, theNew York Timesdespaired: “MURDER AND HANGING-Examples Wanted-Strangle All Our Murderers Together.”
The Marital Patchwork of Colonial South Asia: Forum Shopping from Britain to Baroda
Authors: Sharafi Mitra
Published: October 2010

The British Empire created channels for imperially intended movement. Commodities, bodies, and ideas flowed along axes structured by imperial law and technology. Unintended motion also occurred along these same planes. With every legal structure meant to promote one type of behavior came litigants devising strategies to achieve the opposite. Collusion, bribery, forgery, and perjury were favorite ways to manipulate imperial law. The more permissible strategy of forum shopping was another. Forum shopping is the attempt to push one's case into a jurisdiction promising an optimal result when there is ambiguity over the controlling jurisdiction. It reveals the perception among litigants that bottom-up—and sideways—mechanics exist within legal systems. Unlike work on resistance to state law through extralegal means, I here examine the ways parties tried to work strategically within the confines of the legal system to reconfigure their marital situations. Rather than documenting the success of these maneuvers, however, I note their more common failure. The colonial courts usually saw through unconvincing attempts to forum shop. The fact that litigants continued to try reflects the ingenuity, arguably, of the “legal lottery” mechanism at work in British imperial law. Colonial law, and therefore colonial rule, reinforced its hold on subjects by dangling before them the possibility of individual relief through rule-of-law proceduralism.
Verdi, Solera, Piave and the libretto for Attila
Authors: Izzo Francesco
Published: October 2010

This article clarifies the relationship between Verdi and Solera, shows why it broke down in 1846 and discusses Solera's idiosyncratic verses. It also rereads a widely misunderstood letter that Verdi sent to Solera, which contains not only Piave's emendations to the final act of Attila but also Solera's response to them, angrily scribbled over Piave's work.
P-wave dispersion between transcatheter and surgical closure of secundum-type atrial septal defect in childhood
Authors: Baspinar Osman , Sucu Murat , Koruk Senem , Kervancioglu Mehmet , Ustunsoy Hasim , Deniz Hayati , Kilinc Metin
Published: October 2010

Patients with atrial septal defect have an increased risk for atrial fibrillation. Increased P-wave dispersion predicts the development of atrial fibrillation. The aim of this study was to determine difference in P dispersion between transcatheter closure with Amplatzer septal occluder and surgical closure in childhood. A total of 68 children (the mean age was 7.2 plus or minus 3.3 years; the mean secundum atrial septal defects diameter was 17.3 plus or minus 5.4 millimetres) were evaluated in this study. Transcatheter closure was attempted in 41 children with secundum atrial septal defects, and the defect in 27 patients was closed by surgical techniques. P maximum, P minimum and P dispersion were measured by the 12-lead surface electrocardiography. P maximum, P minimum and P dispersion were found to be similar in patients with pre- and post-procedure (98.0 plus or minus 19.3 versus 95.1 plus or minus 23.0 milliseconds; 68.0 plus or minus 20.8 versus 67.6 plus or minus 24.3 milliseconds, 29.9 plus or minus 11.0 versus 27.1 plus or minus 12.1 milliseconds, respectively). There was no statistical significance in the comparison of P dispersion between the two groups. But in the surgical group, P-wave dispersion was decreased more significantly compared with baseline values (p-value equal to 0.03). In conclusion, there is no P dispersion between transcatheter closure with Amplatzer septal occluder and surgical closure of secundum atrial septal defect.
Emotions and Their Cognitive Control in Children With Cerebellar Tumors
Authors: HOPYAN TALAR , LAUGHLIN SUZANNE , DENNIS MAUREEN
Published: October 2010

A constellation of deficits, termed the cerebellar cognitive affective syndrome (CCAS), has been reported following acquired cerebellar lesions. We studied emotion identification and the cognitive control of emotion in children treated for acquired tumors of the cerebellum. Participants were 37 children (7–16 years) treated for cerebellar tumors (19 benign astrocytomas (AST), 18 malignant medulloblastomas (MB), and 37 matched controls (CON). The Emotion Identification Task investigated recognition of happy and sad emotions in music. In two cognitive control tasks, we investigated whether children could identify emotion in situations in which the emotion in the music and the emotion in the lyrics was either congruent or incongruent. Children with cerebellar tumors identified emotion as accurately and quickly as controls (p > .05), although there was a significant interaction of emotions and group (p < .01), with the MB group performing less accurately identifying sad emotions, and both cerebellar tumor groups were impaired in the cognitive control of emotions (p < .01). The fact that childhood acquired cerebellar tumors disrupt cognitive control of emotion rather than emotion identification provides some support for a model of the CCAS as a disorder, not so much of emotion as of the regulation of emotion by cognition. (JINS, 2010, 16, 1027–1038.)
NONLINEARITIES AND GARCH INADEQUACY FOR MODELING STOCK MARKET RETURNS: EMPIRICAL EVIDENCE FROM LATIN AMERICA
Authors: Bonilla Claudio A. , Romero-Meza Rafael , Maquieira Carlos
Published: October 2010

In this paper, we analyze the adequacy of using GARCH as the data-generating process to model conditional volatility of stock market index rates-of-return series. Using the Hinich portmanteau bicorrelation test, we find that a GARCH formulation or any of its variants fail to provide an adequate characterization for the underlying process of the main Latin American stock market indices. Policymakers need to be careful when using autoregressive models for policy analysis and forecast because the inadequacy of GARCH models has strong implications for the pricing of stock index options, portfolio selection, and risk management. In particular, measures of spillover effects and output volatility may not be correct when GARCH-type models are used to evaluate economic policy.
TECHNOLOGICAL SOURCES OF PRODUCTIVITY GROWTH IN GERMANY, JAPAN, AND THE UNITED STATES
Authors: Rodríguez-López Jesús , Torres José L.
Published: October 2010

In this paper we use a dynamic general equilibrium growth model to quantify the contribution to productivity growth from different technological sources in the three leading economies of the world: Germany, Japan, and the United States. The sources of technology are classified into neutral progress and investment-specific progress. The latter can be split into two different types of equipment: information and communication technologies (ICT) and non-ICT equipment. We find that in the long run, neutral technological change is the main source of productivity growth in Germany and Japan. For the United States, the main source of productivity growth arises from investment-specific technological change, mainly associated with ICT. We also find that a non-negligible part of productivity growth in the three countries has been due to the technology specific to non-ICT equipment.
Using Microscopy to Assess Chorion Structural Integrity and Parasitoid Oviposition Sites on Stink Bug (Hemiptera: Pentatomidae) Eggs
Authors: Koppel A.L. , Herbert D.A. , Westbrook E.W.
Published: October 2010

Previous efficacy studies found that many insecticides used by growers could be having an adverse effect on egg parasitoids (Telenomus podisi) developing in the eggs of the brown stink bug (Euschistus servus), while unhatched stink bugs experienced lower levels of mortality. One plausible explanation for this was that insecticides might enter parasitized eggs more readily via oviposition wounds. Parasitized E. servus eggs, as well as nonparasitized stink bug (Acrosternum hilare, E. servus, Murgantia histrionica, and Podisus maculiventris) eggs, were examined using electron microscopy. Egg response to perforation by a tungsten probe served as a control. Microscopy images depicted the chorion surface as characterized by a matrix of ridges and micropylar processes in a ring around the margin of the operculum. Observations of oviposition sites showed a “scab” formed where the ovipositor penetrated the chorion, and at sites penetrated by the probe. These formations appeared to be the result of fluids from inside the egg leaking out, drying, and hardening after oviposition or probe perforation, suggesting that the response was not due to substances secreted by the parasitoid. Further, no open wounds or holes were seen to increase the possibility of insecticides entering parasitized eggs.
Contesting Europe: the constitutive impact of discursive dynamics on national referendum campaigns
Authors: Seidendorf Stefan
Published: October 2010

A comparison of two referendum campaigns on Europe in France and Ireland shows two different patterns of mobilisation. Focusing on the perceived influence of the European treaties on national legislation on abortion, two different types of Euro-scepticism can be discerned. One is settled in a potentially universal project of ‘enlightenment’ (fearing the ‘criminalisation’ of abortion due to EU (European Union) regulations), the other is concerned with the defence of the nation’s democratic sovereignty against the EU (and fears ‘liberalisation’ of abortion due to the same EU regulations). A discourse analysis of these two different settings establishes the ‘discursive dynamics’ of each campaign: How were actors constituted (into ‘legitimate’ actors) and how could the (differing) interpretations of EU treaty provisions become plausible and constitute into different national discourses? Instead of perceiving social variables (norms, rules, identities) as ‘independent’ factors that explain outcomes, thesocial processof theirconstitutionis at the centre of this analysis. Understanding how and when certain actors and certain topics (orproblematiques) come into being (are ‘constituted’) may, in turn, allow some ‘reasoned claims’ on the character of popular Euro-scepticism.
The transposition of European law in EU member states: between process and politics
Authors: Steunenberg Bernard , Rhinard Mark
Published: October 2010

This paper illuminates a critical stage of the implementation of European law: the transposition of European Union (EU) directives. Directives must be transposed into national policies in order to give effect to European law, yet most national authorities experience considerable transposition difficulties. For this reason, the study of transposition has become a focal point within the broader research agenda on non-compliance in the European Union. Highlighting several popular explanatory variables but noting the sometimes contradictory results that follow from empirical testing, this paper outlines an approach that views transposition as a process taking place largely within ministerial agencies rather than across government systems. By using variables related to these domestic processes in our empirical analysis, the paper shows how such an approach can help to explain the way in which member states transpose EU directives.
Developing attachments to new political institutions: a multi-level model of attitude formation in post-Communist Europe
Authors: Loewenberg Gerhard , Mishler William , Sanborn Howard
Published: October 2010

In America and Western Europe, legislatures preceded democratization and contributed to the establishment and maintenance of democratic regimes in the late 18th and the 19th centuries. In Central and Eastern Europe in the late 20th and early 21st centuries, legislatures and democratic regimes appeared simultaneously. In the first 15 years of post-Communist transitions in 12 countries, attachments to the new regimes have been influenced by their institutional structures, their economic performance, and their records in protecting human freedom, while attachment to the new parliaments have been predominantly influenced by cultural factors related to early life socialization including education, age, gender, social status, and attitudes toward the former communist regime. Attachment to parliament was a product more than a cause of attachment to the new regimes, but the parliamentary system of government created a context that contributed to citizens’ attachment to their new political institutions. In that respect, attitudes toward parliaments in Central and Eastern Europe played a role similar to the role that these attitudes played in an earlier stage of democratization in Europe and North America, the role of attaching citizens to new political institutions.
Die Rolle der PET bei der bildgebenden Untersuchung von Patienten mit malignen Lymphomen
Authors: Klaeser Bernd , Krause Thomas
Published: October 2010

Die Positronen-Emissions-Tomographie (PET) hat sich während der letzten 20 Jahre zum diagnostischen Goldstandard in der Bildgebung einer Mehrzahl von malignen Tumorerkrankungen entwickelt, darunter insbesondere für die bildgebende Untersuchung von Patienten mit malignen Lymphomen. Mit der Entwicklung und Verbreitung von sogenannten Hybridgeräten, die gleichzeitig eine PET-Untersuchung und eine Computertomographie (CT) ermöglichen, und die mit Hilfe fusionierter PET/CT Bilder auch kleinste krankhafte Prozesse zuverlässig zuordnen lassen, wurde die Wertigkeit der Methode nochmals erheblich verbessert. Die hohe Empfindlichkeit der Stoffwechselbildgebung mit PET bzw. PET/CT ermöglicht eine zuverlässige Gesamtbeurteilung von Patienten mit malignen Lymphom für die Stadieneinteilung vor Therapiebeginn, die frühe Diagnose von Therapieversagern unter Therapie sowie das sichere Erkennen von Rezidiven nach Therapie.
The Effects of Guided Notes on Student Learning: Students Share Their Perceptions
Authors: Friberg Jennifer C. , Sawyer Jean
Published: October 2010

Guided notes have been used in a variety of ways to support students as they learn new material within various classroom settings. Historically, guided notes have been studied relative to their impact on student learning, rather than student engagement in the learning process. To that end, this study sought to determine the perceptions of 144 graduate and undergraduate students who used guided notes with regard to their impact upon class participation, reflection on course topics, mastery of course information, and overall note taking preferences. Results indicated that students valued the use of guided notes to serve certain purposes, but seemed to prefer the use of more traditional note taking procedures for others.
Prototype high resolution multienergy soft x-ray array for NSTX
Authors: Tritz K. , Stutman D. , Delgado-Aparicio L. , Finkenthal M. , Kaita R. , Roquemore L.
Published: October 2010

A novel diagnostic design seeks to enhance the capability of multienergy soft x-ray (SXR) detection by using an image intensifier to amplify the signals from a larger set of filtered x-ray profiles. The increased number of profiles and simplified detection system provides a compact diagnostic device for measuring Te in addition to contributions from density and impurities. A single-energy prototype system has been implemented on NSTX, comprised of a filtered x-ray pinhole camera, which converts the x-rays to visible light using a CsI:Tl phosphor. SXR profiles have been measured in high performance plasmas at frame rates of up to 10 kHz, and comparisons to the toroidally displaced tangential multi-energy SXR have been made.
Measuring the density of a molecular cluster injector via visible emission from an electron beam
Authors: Lundberg D. P. , Kaita R. , Majeski R. , Stotler D. P.
Published: October 2010

A method to measure the density distribution of a dense hydrogen gas jet is presented. A Mach 5.5 nozzle is cooled to 80 K to form a flow capable of molecular cluster formation. A 250 V, 10 mA electron beam collides with the jet and produces Hα emission that is viewed by a fast camera. The high density of the jet, several 1016 cm−3, results in substantial electron depletion, which attenuates the Hα emission. The attenuated emission measurement, combined with a simplified electron-molecule collision model, allows us to determine the molecular density profile via a simple iterative calculation.
Residual gas analysis for long-pulse, advanced tokamak operation
Authors: Klepper C. C. , Hillis D. L. , Bucalossi J. , Douai D. , Oddon P. , Vartanian S. , Colas L. , Manenc L. , Pégourié B.
Published: October 2010

A shielded residual gas analyzer (RGA) system on Tore Supra can function during plasma operation and is set up to monitor the composition of the neutral gas in one of the pumping ducts of the toroidal pumped limited. This “diagnostic RGA” has been used in long-pulse (up to 6 min) discharges for continuous monitoring of up to 15 masses simultaneously. Comparison of the RGA-measured evolution of the H2/D2 isotopic ratio in the exhaust gas to that measured by an energetic neutral particle analyzer in the plasma core provides a way to monitor the evolution of particle balance. RGA monitoring of corrective H2 injection to maintain proper minority heating is providing a database for improved ion cyclotron resonance heating, potentially with RGA-base feedback control. In very long pulses (>4 min) absence of significant changes in the RGA-monitored, hydrocarbon particle pressures is an indication of proper operation of the actively cooled, carbon-based plasma facing components. Also H2 could increase due to thermodesorption of overheated plasma facing components.
Uncertainty analysis technique for OMEGA Dante measurements
Authors: May M. J. , Widmann K. , Sorce C. , Park H.-S. , Schneider M.
Published: October 2010

The Dante is an 18 channel x-ray filtered diode array which records the spectrally and temporally resolved radiation flux from various targets (e.g., hohlraums, etc.) at x-ray energies between 50 eV and 10 keV. It is a main diagnostic installed on the OMEGA laser facility at the Laboratory for Laser Energetics, University of Rochester. The absolute flux is determined from the photometric calibration of the x-ray diodes, filters and mirrors, and an unfold algorithm. Understanding the errors on this absolute measurement is critical for understanding hohlraum energetic physics. We present a new method for quantifying the uncertainties on the determined flux using a Monte Carlo parameter variation technique. This technique combines the uncertainties in both the unfold algorithm and the error from the absolute calibration of each channel into a one sigma Gaussian error function. One thousand test voltage sets are created using these error functions and processed by the unfold algorithm to produce individual spectra and fluxes. Statistical methods are applied to the resultant set of fluxes to estimate error bars on the measurements.
Two-chord interferometry using 3.39 μm He–Ne laser on a flux-coil-generated FRC
Authors: Gota H. , Bolte N. , Deng B. H. , Gupta D. , Kiyashko V. , Knapp K. , Mendoza R. , Morehouse M. , Roche T. , Wessel F.
Published: October 2010

A two-chord λIR∼3.39 μm He–Ne laser interferometer system was developed for a flux-coil-generated field-reversed configuration to estimate the electron density and the total temperature of the field-reversed configuration (FRC) plasma. This two-chord heterodyne interferometer system consists of a single ∼2 mW infrared He–Ne laser, a visible (λvis∼632.8 nm) He–Ne laser for the alignment, a 40 MHz acousto-optic modulator, photodetectors, and quadrature phase detectors. Initial measurement was performed and the measured average electron densities were 2–10×1019 m−3 at two different radial positions in the midplane. A time shift in density was observed as the FRC expands radially. The time evolution of the line-averaged density agrees with the density estimated from the in situ internal magnetic probes, based on a rigid-rotor profile model.
Critical behavior of self-assembled rigid rods on triangular and honeycomb lattices
Authors: López L. G. , Linares D. H. , Ramirez-Pastor A. J.
Published: October 2010

Using Monte Carlo simulations and finite-size scaling analysis, the critical behavior of self-assembled rigid rods on triangular and honeycomb lattices at intermediate density has been studied. The system is composed of monomers with two attractive (sticky) poles that, by decreasing temperature or increasing density, polymerize reversibly into chains with three allowed directions and, at the same time, undergo a continuous isotropic-nematic (IN) transition. The determination of the critical exponents, along with the behavior of Binder cumulants, indicate that the IN transition belongs to the q=1 Potts universality class.
Efficient calculation of temperature dependence of solid-phase free energies by overlap sampling coupled with harmonically targeted perturbation
Authors: Tan Tai Boon , Schultz Andrew J. , Kofke David A.
Published: October 2010

We examine a method for computing the change in free energy with temperature of a crystalline solid. In the method, the free-energy difference between nearby temperatures is calculated via overlap-sampling free-energy perturbation with Bennett’s optimization. Coupled to this is a harmonically targeted perturbation that displaces the atoms in a manner consistent with the temperature change, such that for a harmonic system, the free-energy difference would be recovered with no error. A series of such perturbations can be assembled to bridge larger gaps in temperature. We test this harmonically targeted temperature perturbation (HTTP) method through the application to the inverse-power soft potential, u(r)=ε(σ/r)n, over a range of temperatures up to the melting condition. Three exponent values (n=12, 9, and 6) for the potential are studied with different crystal structures, specifically face-centered cubic (fcc), body-centered cubic (bcc), and hexagonal close packing. Absolute free energies (classical only) for each system are obtained by implementing the series to near-zero temperature, where the harmonic model becomes very accurate. The HTTP method is shown to provide very precise results, with errors in the free energy smaller than two parts in 105. An analysis of the thermodynamic stability of the various structures in the infinite-system limit confirms previous findings. In particular, for n=12 and 9, the fcc structure is stable for all temperatures up to melting, and for n=6, the bcc crystal becomes stable relative to fcc for temperatures above kT/ε=0.802±0.001. The effects of vacancies and other defects are not considered in the analysis.
Chiral properties in a two-dimensional chiral polaritonic photonic crystal
Authors: He Cheng , Lu Ming-Hui , Yin Ruo-Cheng , Fan Tian , Chen Yan-Feng
Published: October 2010

We theoretically investigated a format of two-dimensional dielectric-chiral photonic crystal structure that is composed of a dispersive chiral medium embedded in a dielectric background. The photonic band structure shows distinctive dispersion relationship for circularly polarized electromagnetic waves, leading to a number of intriguing wave properties, namely chirality dependent “node switching,” polarization sensitive transmission and handedness dependent mode localization. All of these effects are attributed to the strong interaction between the local resonant modes around the dispersive chiral rods and the Bloch modes of the bulk waves. The chirality dependent properties can find tremendous applications in polarization based optoelectronics devices and rapid separation of chiral compounds in pharmaceutical industry.
Radiative cooling of bulk Si by optical down-conversion
Authors: Malyutenko V. K. , Bogatyrenko V. V. , Malyutenko O. Yu.
Published: October 2010

We report on the radiative cooling of an indirect band gap semiconductor through its absorption of interband incoherent light and subsequent spontaneous emission of multiple longer-wavelength photons (optical down-conversion) in conditions when the energy deficit of the process is covered by the thermal energy. The 10×10×5 mm3 Si slab kept at 473 K in an evacuated up to 10−3 torr chamber was cooled by 3.8 K when pumped with light of 1.06 μm wavelength. First-principles estimates and several advantages of the down-conversion approach over possible cooling of direct band gap semiconductors through the optical upconversion and negative luminescence are discussed.
A theoretical investigation on the honeycomb potential fluid
Authors: Zhou Shiqi
Published: October 2010

A local self-consistent Ornstein–Zernike (OZ) integral equation theory (IET) is proposed to provide a rapid route for obtaining thermodynamic and structural information for any thermodynamically stable or metastable state points in the bulk phase diagram without recourse to traditional thermodynamic integration, and extensive NVT-Monte Carlo simulations are performed on a recently proposed honeycomb potential in three dimensions to test the theory’s reliability. The simulated quantities include radial distribution function (rdf) and excess internal energy, pressure, excess chemical potential, and excess Helmholtz free energy. It is demonstrated that (i) the theory reproduces the rdf very satisfactorily only if the bulk state does not enter deep into a two phases coexistence region; (ii) the excess internal energy is the only one of the four thermodynamic quantities investigated amenable to the most accurate prediction by the present theory, and the simulated pressure is somewhat overestimated by the theoretical calculations, but the deviation tends to vanish along with rising of the temperature; (iii) using the structural functions from the present local self-consistent OZ IET, a previously derived local expression, due to the present author, achieves even a higher accuracy in calculating for the excess chemical potential than the exact virial pressure formula for the pressure, and the resulting excess Helmholtz free energy is in surprisingly same with the simulation results due to offset of the errors. Based on the above observations, it is suggested that it may be a good procedure to integrate the theoretical excess internal energy along the isochors to get the excess Helmholtz free energy, which is then fitted to a polynomial to be used for calculation of all of other thermodynamic quantities in the framework of the OZ IET.
A double bend achromat lattice for the Pohang Light Source to reduce emittance and increase number of insertion devices
Authors: Kim Eun-San
Published: October 2010

The Pohang Light Source (PLS) storage ring is a synchrotron light source with the emittance of 18.9 nm at 2.5 GeV and has delivered vacuum ultraviolet and soft x-rays during the past 15 years. We investigate a lattice design for the 3 GeV ring for an upgrade project that keeps the existing tunnel. We investigate a double bend achromat (DBA) structure that provides the reduction of emittance by a factor of 3 and the increase of the number of straight section by a factor of 2 than the existing PLS lattice. We present several characteristics on the beam dynamics, dynamic aperture, and optics matching in the low-emittance lattice which includes squeezed space between magnets. Present PLS lattice has 12 long straight sections of 6.8 m long and the lattice is modified to provide the additional 12 short straight sections of 3.7 m long by eliminating a bending magnet in the middle of the cell of the present triplet bending achromat lattice. Thus, the new lattice consists of a total of 24 straight sections that consist of 12×6.8 and 12×3.7 m long straight sections, which can provide the spaces for the 4- and 2-m-long insertion devices. We present the design results in detail for a DBA lattice in 281.82 m long circumference. It is shown that the emittance of 6.2 nm in the lattice can be achieved by allowing nonzero dispersions in the straight sections. The lattice provides high brilliance at the photon energy of a few 10 keV that meets the requirements by synchrotron radiation users; however, it may require a strong focusing and become sensitive to machine errors and effects of insertion devices. Thus, we investigated the dynamic aperture in the lattice by a simulation method and achieved an optimal tune under the strength of sextupole magnets of 500 T/m2 for the low-emittance ring. We also performed the lattice tunings to restore the optics due to the errors in the low-emittance ring. In result, our designed lattice shows a good optimization in terms of emittance, brilliance, and circumference as a light source for a 3 GeV.
Interlayer exchange coupling and its temperature dependence in [Pt/Co]4/MgO/[Co/Pt]2 perpendicular magnetic tunnel junctions
Authors: Li L. , Zhang F. , Wang N. , Lv Y. F. , Han X. Y. , Zhang J. J.
Published: October 2010

In the [Pt/Co]4/MgO/[Co/Pt]2 perpendicular magnetic tunnel junctions, we have observed antiferromagnetic interlayer coupling when the spacer thickness is larger than 12 Å, and a transition to ferromagnetic coupling for lower MgO thickness. The dependence of the interlayer coupling strength on the MgO spacer thickness is well fitted by the theory of free-electron model, providing an unambiguous experimental proof for interlayer exchange coupling theory. The thermal behavior of interlayer coupling shows a translation from antiferromagnetic to ferromagnetic coupling at 145 K. It can be mainly ascribed to the temperature-dependent enhancement of the magnetization of the ferromagnetic layers.
High reflectivity electrofluidic pixels with zero-power grayscale operation
Authors: Yang S. , Zhou K. , Kreit E. , Heikenfeld J.
Published: October 2010

Electrofluidic display pixels are demonstrated with zero-power grayscale operation for 3 months and with >70% reflectance. The color of the pixel is changed as electrowetting moves the pigment dispersion between a top and bottom channel. When voltage is removed, a near zero Laplace pressure and a hysteresis pressure of 0.11 kN/m2 stabilizes the position. For 450 μm pixels, an electromechanical pressure of 1.4 kN/m2 moves the pigment dispersion at a speed of ∼2650 μm/s. The predicted switching speed for ∼150 μm pixels is consistent with video rate operation (20 ms). The geometrically sophisticated pixel structure is fabricated with only simple photolithography and wet chemical processing.
Concentration dependence of the transport energy level for charge carriers in organic semiconductors
Authors: Oelerich J. O. , Huemmer D. , Weseloh M. , Baranovskii S. D.
Published: October 2010

The concept of the transport energy (TE) has proven to be one of the most powerful theoretical approaches to describe charge transport in organic semiconductors. In the recent paper L. Li, G. Meller, and H. Kosina [Appl. Phys. Lett. 92, 013307 (2008)] have studied the effect of the partially filled localized states on the position of the TE level. We show that the position of the TE is essentially different to the one suggested by L. Li, G. Meller, and H. Kosina [Appl. Phys. Lett. 92, 013307 (2008)] We further modify the standard TE approach taking into account the percolation nature of the transport path. Our calculations show that the TE becomes dependent on the concentration of charge carriers n at much higher n values than those, at which the carrier mobility already strongly depends on n. Hence the calculations of the concentration-dependent carrier mobility cannot be performed within the approach, in which only the concentration dependence of the TE is taken into account.
Experimental verification of improving high-power microwave window breakdown thresholds by resonant magnetic field
Authors: Chang Chao , Fang Jinyong , Zhang Zhiqiang , Chen Changhua , Tang Chuanxiang , Jin Qiuliang
Published: October 2010

Recently, high-power microwave (HPM) dielectric multipactor is theoretically discovered to be suppressed by utilizing external resonant magnetic field. This paper gives the related experimental demonstration of increasing the vacuum window breakdown thresholds. In the S-band HPM experiment with 0.5 μs width, the magnetic field with gyrofrequency Ω close to rf frequency ω can triple the breakdown threshold. Besides, reducing or enhancing magnetic field resulted in a relatively lower threshold in comparison of Ω∼ω, agreeing with theoretical analysis. By HPM pulse compression to 14 ns width, the threshold was also demonstrated to be significantly enhanced by magnetic field.
Noise performance of lumped element direct current superconducting quantum interference device amplifiers in the 4–8 GHz range
Authors: Spietz Lafe , Irwin Kent , Lee Minhyea , Aumentado José
Published: October 2010

We report on the noise of a lumped element direct current superconducting quantum interference device amplifier. We show that the noise temperature in the 4–8 GHz range over ranges of tens of megahertz is below 1 K (three photons of added noise), characterize the overall behavior of the noise as a function of bias parameters, and discuss potential mechanisms which determine the noise performance in this amplifier. We show that this device can provide more than a factor of 10 improvement in practical system noise over existing phase-preserving microwave measurement systems in this frequency band.
Kinesin-1 and dynein at the nuclear envelope mediate the bidirectional migrations of nuclei
Authors: Fridolfsson Heidi N. , Starr Daniel A.
Published: October 2010

Kinesin-1 and dynein are recruited to the nuclear envelope by the Caenorhabditis elegans klarsicht/ANC-1/Syne homology (KASH) protein UNC-83 to move nuclei. The mechanisms of how these motors are coordinated to mediate nuclear migration are unknown. Time-lapse differential interference contrast and fluorescence imaging of embryonic hypodermal nuclear migration events were used to characterize the kinetics of nuclear migration and determine microtubule dynamics and polarity. Wild-type nuclei display bidirectional movements during migration and are also able to roll past cytoplasmic granules. unc-83, unc-84, and kinesin-1 mutants have severe nuclear migration defects. Without dynein, nuclear migration initiates normally but lacks bidirectional movement and shows defects in nuclear rolling, implicating dynein in resolution of cytoplasmic roadblocks. Microtubules are highly dynamic during nuclear migration. EB1::green fluorescence protein imaging demonstrates that microtubules are polarized in the direction of nuclear migration. This organization of microtubules fits with our model that kinesin-1 moves nuclei forward and dynein functions to move nuclei backward for short stretches to bypass cellular roadblocks.
Distinct structural rearrangements of the VSV glycoprotein drive membrane fusion
Authors: Libersou Sonia , Albertini Aurélie A.V. , Ouldali Malika , Maury Virginie , Maheu Christine , Raux Hélène , de Haas Felix , Roche Stéphane , Gaudin Yves , Lepault Jean
Published: October 2010

The entry of enveloped viruses into cells requires the fusion of viral and cellular membranes, driven by conformational changes in viral glycoproteins. Many studies have shown that fusion involves the cooperative action of a large number of these glycoproteins, but the underlying mechanisms are unknown. We used electron microscopy and tomography to study the low pH–induced fusion reaction catalyzed by vesicular stomatitis virus glycoprotein (G). Pre- and post-fusion crystal structures were observed on virions at high and low pH, respectively. Individual fusion events with liposomes were also visualized. Fusion appears to be driven by two successive structural rearrangements of G at different sites on the virion. Fusion is initiated at the flat base of the particle. Glycoproteins located outside the contact zone between virions and liposomes then reorganize into regular arrays. We suggest that the formation of these arrays, which have been shown to be an intrinsic property of the G ectodomain, induces membrane constraints, achieving the fusion reaction.
A phase-reduced neuro-mechanical model for insect locomotion: feed-forward stability and proprioceptive feedback
Authors: Proctor J. , Kukillaya R. P. , Holmes P.
Published: October 2010

In earlier work, we have developed an integrated model for insect locomotion that includes a central pattern generator (CPG), nonlinear muscles, hexapedal geometry and a representative proprioceptive sensory pathway. Here, we employ phase reduction and averaging theory to replace 264 ordinary differential equations (ODEs), describing bursting neurons in the CPG, their synaptic connections to motoneurons, muscle activation dynamics and sensory neurons, with 24 one-dimensional phase oscillators that describe motoneuronal activation of agonist–antagonist muscle pairs driving the jointed legs. Reflexive feedback is represented by stereotypical spike trains with rates proportional to joint torques, which change phase relationships among the motoneuronal oscillators. Restriction to the horizontal plane, neglect of leg mass and use of Hill-type muscle models yield a biomechanical body–limb system with only three degrees of freedom, and the resulting hybrid dynamical system involves 30 ODEs: reduction by an order of magnitude. We show that this reduced model captures the dynamics of unperturbed gaits and the effects of an impulsive perturbation as accurately as the original one. Moreover, the phase response and coupling functions provide an improved understanding of reflexive feedback mechanisms.
A hybrid approach to multi-scale modelling of cancer
Authors: Osborne J. M. , Walter A. , Kershaw S. K. , Mirams G. R. , Fletcher A. G. , Pathmanathan P. , Gavaghan D. , Jensen O. E. , Maini P. K. , Byrne H. M.
Published: October 2010

In this paper, we review multi-scale models of solid tumour growth and discuss a middle-out framework that tracks individual cells. By focusing on the cellular dynamics of a healthy colorectal crypt and its invasion by mutant, cancerous cells, we compare a cell-centre, a cell-vertex and a continuum model of cell proliferation and movement. All models reproduce the basic features of a healthy crypt: cells proliferate near the crypt base, they migrate upwards and are sloughed off near the top. The models are used to establish conditions under which mutant cells are able to colonize the crypt either by top-down or by bottom-up invasion. While the continuum model is quicker and easier to implement, it can be difficult to relate system parameters to measurable biophysical quantities. Conversely, the greater detail inherent in the multi-scale models means that experimentally derived parameters can be incorporated and, therefore, these models offer greater scope for understanding normal and diseased crypts, for testing and identifying new therapeutic targets and for predicting their impacts.