bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic anti‐windup design in anticipation of actuator saturation
Authors: Wu Xiongjun , Lin Zongli
Published: August 2012

In a traditional anti‐windup design, the anti‐windup mechanism is set to be activated as soon as the control signal saturates the actuator. A recent innovation of delaying the activation of the anti‐windup mechanism, both static and dynamic, until the saturation reaches a certain level of severity has led to a performance improvement of the resulting closed‐loop system. It has been shown that significant further performance improvements can be obtained by activating a static anti‐windup mechanism in anticipation of actuator saturation, instead of immediate or delayed activation. This paper demonstrates that anticipatory activation of a dynamic anti‐windup mechanism would also lead to significant performance improvements over both the immediate and delayed activation schemes.Copyright © 2012 John Wiley & Sons, Ltd.
Critical behavior in inhomogeneous random graphs
Authors: van der Hofstad Remco
Published: August 2012

We study the critical behavior of inhomogeneous random graphs in the so‐called rank‐1 case, where edges are present independently but with unequal edge occupation probabilities. The edge occupation probabilities are moderated by vertex weights, and are such that the degree of vertex i is close in distribution to a Poisson random variable with parameter wi, where wi denotes the weight of vertex i. We choose the weights such that the weight of a uniformly chosen vertex converges in distribution to a limiting random variable W. In this case, the proportion of vertices with degree k is close to the probability that a Poisson random variable with random parameter W takes the value k. We pay special attention to the power‐law case, i.e., the case where
\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}{\mathbb{P}}(W\geq k)\end{align*} \end{document}
is proportional to k‐(τ‐1) for some power‐law exponent τ > 3, a property which is then inherited by the asymptotic degree distribution.

We show that the critical behavior depends sensitively on the properties of the asymptotic degree distribution moderated by the asymptotic weight distribution W. Indeed, when
\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}{\mathbb{P}}(W > k) \leq ck^{-(\tau-1)}\end{align*} \end{document}
for all k ≥ 1 and some τ > 4 and c > 0, the largest critical connected component in a graph of size n is of order n2/3, as it is for the critical Erdős‐Rényi random graph. When, instead,
\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}{\mathbb{P}}(W > k)=ck^{-(\tau-1)}(1+o(1))\end{align*} \end{document}
for k large and some τ∈(3,4) and c > 0, the largest critical connected component is of the much smaller order n(τ‐2)/(τ‐1). © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 42, 480–508, 2013
Mixing times for the Swapping Algorithm on the Blume‐Emery‐Griffiths model
Authors: Ebbers Mirko , Knöpfel Holger , Löwe Matthias , Vermet Franck
Published: August 2012

We analyze the so called Swapping Algorithm, a parallel version of the well‐known Metropolis‐Hastings algorithm, on the mean‐field version of the Blume‐Emery‐Griffiths model in statistical mechanics. This model has two parameters and depending on their choice, the model exhibits either a first, or a second order phase transition. In agreement with a conjecture by Bhatnagar and Randall we find that the Swapping Algorithm mixes rapidly in presence of a second order phase transition, while becoming slow when the phase transition is first order. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 45, 38–77, 2014
Comparing competing risk outcomes within principal strata, with application to studies of mother‐to‐child transmission of HIV
Authors: Long Dustin M. , Hudgens Michael G.
Published: August 2012

In randomized trials to prevent breast milk transmission of human immunodeficiency virus (HIV) from mother to infant, investigators are often interested in assessing the effect of a treatment or intervention on the cumulative risk of HIV infection by time (age) t in infants who are alive and uninfected at a certain time point τ0 < t. Such comparisons are challenging for two reasons. First, infants are typically randomized at birth (time 0 < τ0) such that comparisons between trial arms among the subset of infants alive and uninfected at τ0 are subject to selection bias. Second, in most mother‐to‐child transmission (MTCT) trials competing risks are often present, such as death or cessation of breastfeeding prior to HIV infection. In this paper, we present methods for assessing the causal effect of a treatment on competing risk outcomes within principal strata. In MTCT trials, the causal effect of interest is that of treatment on the risk of HIV infection by time t > τ0 within the principal stratum of infants who would be alive and uninfected by τ0 regardless of randomization assignment. We develop large sample nonparametric bounds and a semiparametric sensitivity analysis model for drawing inference about this causal effect. We present a simulation study demonstrating that the proposed methods perform well in finite samples. We apply the proposed methods to a large, recent MTCT trial. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis and characterization of two pet radioligands for the metabotropic glutamate 1 (mGlu1) receptor
Authors: Huang Yiyun , Narendran Rajesh , Bischoff Francois , Guo Ningning , Bae Sung A. , Hwang Dah‐Ren , Lesage Anne S. , Laruelle Marc
Published: August 2012

The metabotropic glutamate 1 receptor (mGlu1) is an important protein in the regulation of glutamate transmission in the brain, and believed to be involved in disorders such as ischemia, epilepsy, neuropathic pain, anxiety, and schizophrenia. The goal of this study was to evaluate two selective mGlu1 antagonists [11C]3 and [18F]4 as potential PET radioligands for the in vivo imaging of the mGlu1 receptor. Biodistribution studies in rats indicated high uptake of [11C]3 and [18F]4 in the brain. The highest activity level was found in the cerebellum, followed by striatum, hippocampus, frontal cortex, and medulla, in a pattern consistent with the distribution of mGlu1 receptor in rat. At 30 min postinjection, the activity ratio of cerebellum to medulla was 4.5 for [11C]3, indicating a high degree of specific binding, while specific binding was lower for [18F]4 (cerebellum to medulla activity ratio of 2.0). Moreover, binding of the radioligands [11C]3 and [18F]4 in mGlu1 receptor‐rich region such as cerebellum was blocked by pretreatment of the rats with their respective unlabeled compound or the selective mGlu1 antagonist (compound 5, 2 mg/kg each), but not by the selective mGlu2 antagonist LY341495, or the selective mGlu5 antagonist MPEP (2 mg/kg), thus indicating the binding specificity and selectivity of [11C]3 and [18F]4 to the mGlu1 receptor. However, in imaging experiments in baboons [11C]3 displayed a small specific binding signal only in the cerebellum, while the specific binding of [18F]4 was difficult to detect. Species differences in receptor density and affinity of the radioligands in large part account for the differences in the behavior of [11C]3 and [18F]4 in rats and baboons. Radioligands with higher affinity and/or lower lipophilicity are needed to successfully image the mGlu1 receptor in humans. Synapse, 2012. © 2012 Wiley Periodicals, Inc.
Investigation of Park–Ang damage index model for flexural behavior of reinforced concrete columns
Authors: Rajabi Roohollah , Barghi Mostafa , Rajabi Reza
Published: August 2012

One of the most popular damage indexes for reinforced concrete (RC) members is Park–Ang damage index model. This model has been established on the basis of experimental results of RC beams and columns with different modes of damage. It has considerable uncertainty on the basis of its authors' remarks. In this study, precision of Park–Ang model for RC columns is improved by using some experimental results from Pacific Earthquake Engineering Research information bank. In proposed model, it focused on RC columns with specific sections and collapse modes. Finally, in order to define damage index more exactly in concrete columns under seismic loadings, capability of IDARC‐2D computer program has been improved by this proposed model. Copyright © 2012 John Wiley & Sons, Ltd.
Development of a geophysic model output statistics module for improving short‐term numerical wind predictions over complex sites
Authors: Bédard Joël , Yu Wei , Gagnon Yves , Masson Christian
Published: August 2012

Developed for short‐term (0–48 h) wind power forecasting purposes, high‐resolution meteorological forecasts for Eastern Canada are available from Environment Canada's Numerical Weather Prediction (NWP) model configured on a limited area (GEM‐LAM). This paper uses 3 years of forecast data from this model for the region of North Cape (Prince Edward Island, Canada). Although the model resolution is relatively high (2.5 km), statistical analysis and site inspection reveal that the model does not have a sufficiently refined grid to properly represent the meteorological phenomena over this complex coastal site. To cope with such representation error, a generalized Geophysic Model Output Statistics (GMOS) module is developed and applied to reduce the forecast error of the NWP forecasts. GMOS differs from other Model Output Statistics (MOS) that are widely used by meteorological centres in the following aspects: (i) GMOS takes into account the surrounding geophysical parameters such as surface roughness, terrain height, etc., along with wind direction; (ii) GMOS can be directly applied for model output correction without any training.

Compared with other methods, GMOS using a multiple grid point approach improves the GEM‐LAM predictions root mean squared error by 1–5% for all time horizons and most meteorological conditions. Also, the topographic signature of the forecast error (uneven directional distribution of the forecast error related to the surface characteristics) due to misrepresentation issues is significantly reduced. The NWP forecasts combined with GMOS outperform the persistence model from a 2 h horizon, instead of 3 h using MOS. Finally, GMOS is applied and validated at two other sites located in New Brunswick, Canada. Similar improvements on the forecasts were observed, thus showing the general applicability of GMOS. Copyright © 2012 John Wiley & Sons, Ltd.
Mesh and load distribution requirements for actuator line CFD simulations
Authors: Shives Michael , Crawford Curran
Published: August 2012

Fundamental numerical testing has been carried out to determine mesh density and force distribution guidelines for an actuator line‐based computational fluid dynamics method for simulating kinetic turbines. The method computes forces from lifting surfaces (i.e. wings or blades) by using the evolving flowfield and tabulated airfoil data. The forces are applied to the flow as momentum source terms distributed with a Gaussian smoothing function about the physical locations of the blade/wing quarter‐chord line. The chosen length scale of the Gaussian distribution affects the magnitude and distribution of the resulting induction and necessitates a minimum grid resolution for accurate results. Tests have been conducted to determine appropriate distribution length scales and mesh spacing by using an infinite span wing and finite span wings with constant and elliptical spanwise circulation distributions. These test cases were chosen because they have simple analytical solutions derived from lifting line theory. The eventual goal is to simulate turbine rotors; however, these fundamental test cases provide a means to evaluate the required mesh spacing and the appropriate distribution length scale without the complexity of modeling a turbine rotor wake. It was found that the source distribution length scale ϵ should be proportional to the local airfoil chord length c with a ratio ϵ / c of approximately 1/4 and that the mesh spacing at the actuator line should satisfy ϵ / Δgrid ≥ 4. This limit is likely somewhat code specific and should be evaluated for all solvers used for actuator line simulations. Copyright © 2012 John Wiley & Sons, Ltd.
Data‐free speculation does not make for testable hypotheses: A reply to Ripple et al.
Authors: Hodges Karen E.
Published: August 2012

The role of top predators in structuring ecosystems is receiving substantial attention from ecologists. Ripple et al. (2011) recently posed a tentatively supported hypothesis that wolves (Canis lupus) may help restore populations of the U.S. federally Threatened Canada lynx (Lynx canadensis), a specialist predator on snowshoe hares (Lepus americanus), through 2 possible mechanisms: a) decreases in the numbers of coyotes (C. latrans), which may compete with lynx for hares as prey and may also kill lynx; or b) decreases in ungulates that might compete with hares for food. These speculative opinions are not supported by current data, either across the range or in the extended example of Yellowstone National Park (YNP) that Ripple et al. provide. The coyote hypothesis lacks the required quantification of coyote numbers and predation rates on hares, both in YNP and across the range of lynx. The browse competition hypothesis ignores substantial differences in browse and habitat preferences between elk (Cervus elaphus) or livestock and hares that prevent competition for food. Our previous work in YNP (Hodges et al. 2009) showed scattered and very low densities of snowshoe hares, with distributions driven by the substantial fire‐related habitat changes YNP has experienced over the past century. Although I applaud their interest in lynx conservation, the unsupported speculations of Ripple et al. do not advance our ability to manage lynx or hares, nor do they present plausible directions for conservation research. © 2012 The Wildlife Society.
Supermembrane interaction with dynamical D = 4 N = 1 supergravity. Superfield Lagrangian description and spacetime equations of motion
Authors: Bandos Igor A. , Meliveo Carlos
Published: August 2012

Abstract

We obtain the complete set of equations of motion for the interacting system of supermembrane and dynamical D = 4
$ \mathcal{N} $
= 1 supergravity by varying its complete superfield action and writing the resulting superfield equations in the special
$ ``{\text{W}}{{\text{Z}}_{{\widehat{\theta } = 0}}}'' $
gauge where the supermembrane Goldstone field is set to zero
$ \left( {\widehat{\theta } = 0} \right) $
. We solve the equations for auxiliary fields and discuss the effect of dynamical generation of cosmological constant in the Einstein equation of interacting system and its renormalization due to some regular contributions from supermembrane. These two effects (discussed in late 70th and 80th, in the bosonic perspective and in the supergravity literature) result in that, generically, the cosmological constant has different values in the branches of the spacetime separated by the supermembrane worldvolume.
Supersymmetric AdS vacua and separation of scales
Authors: Tsimpis Dimitrios
Published: August 2012

Abstract

The moduli space of the supersymmetric massive IIA AdS4 × S
2(B4) vacua, where S
2(B4) is a two-sphere bundle over a four-dimensional Kähler-Einstein base B4, includes three independent parameters which can be thought of as corresponding to the sizes of AdS4, B4 and the S
2 fiber. It might therefore be expected that these vacua do not suffer from the absence of scale separation. We show that the independence of the geometric moduli survives flux quantization. However, we uncover an attractor behavior whereby all sizes flow to equality in some neighborhood of spacetime independently of the initial conditions set by the parameters of the solution. This is further confirmed by the study of the ratio of internal to external scalar curvatures. We also show that the asymptotic Kaluza-Klein spectrum of a ten-dimensional massive scalar is governed by a scale of the order of the AdS4 radius. Furthermore we point out that the curvature ratio in supersymmetric IIA AdS4 vacua with rigid SU(3) structure is of order one, indicating the absence of scale separation in this large class of vacua.
Analysis of One and Two-Story Single Family Home Fire Dynamics and the Impact of Firefighter Horizontal Ventilation
Authors: Kerber Stephen
Published: August 2012

This paper describes experimental investigations on fire service ventilation practices in modern house geometries. Two houses were constructed inside a large fire facility. The first of two houses constructed was a one-story, 111.5 m2, 3 bedroom, 1 bathroom house with 8 total rooms. The second house was a two-story 297.3 m2, 4 bedroom, 2.5 bathroom house with 12 total rooms. The second house featured a modern open floor plan, two-story great room and open foyer. Fifteen experiments were conducted varying the ventilation locations and the number of ventilation openings. Ventilation scenarios included ventilating the front door only, opening the front door and a window near and remote from the seat of the fire, opening a window only and ventilating a higher opening in the two-story house. One scenario in each house was conducted in triplicate to examine repeatability. The results of these experiments examine potential occupant tenability and provide knowledge for the fire service for them to examine their horizontal ventilation standard operating procedures and training content. The fire dynamics resulting from ventilation practices such as ventilation near or remote from the seat of the fire and high versus low in relation to the fire are examined. Several other tactical considerations were developed utilizing the data from these experiments to provide specific examples of changes that can be adopted based on a departments current strategies and tactics. Such tactical considerations and a systems approach to fire service tactics should be investigated further.
Beads and Dice in a Genetic Drift Exercise
Authors: Russo Claudia A. M. , Voloch Carolina M.
Published: August 2012

Natural selection driving adaptive changes is a powerful and intuitive explanation for the evolution of the living world around us. Evolution at the molecular level, however, is chiefly ruled by random genetic drift. The idea that an advantageous allele may be lost by chance in a natural population is rather difficult to explore in the classroom. Low-cost and hands-on educational resources are needed to make genetic drift more intuitive among students. In this exercise, we use colored beads and the roll of a die to simulate drift and selection jointly affecting the fate of the genetic variants in an evolving population. Our aim is to teach students that natural selection does not determine but simply influences the fate of advantageous alleles because random genetic drift is always present. We have been using this exercise successfully for over a decade for the Biological Sciences students at the Federal University of Rio de Janeiro.
Darwinism and the Origin of Life
Authors: Peretó Juli , Català Jesús
Published: August 2012

Historically, ideas on the origins of life have been mingled with evolutionary explanations. Darwin avoided discussing the origin of the very first species in public although he acknowledged the possibility that life originated by natural causes. Some of his followers adopted this materialistic position and advocated some sort of spontaneous generation in the distant past. Nevertheless, Pasteur’s experiments were a major obstacle for scientific acceptance of the sudden emergence of life. The scientific study of the origin of life, established in the 1920s, required abandoning the idea of a unique chance event and considering a view of life emerging as the result of a long evolutionary process. At the turn of the twentieth century, some authors adopted non-Darwinian views on the origin of life, exemplified in this paper by the neovitalism of some Catholic scientists. We propose that Darwinism represents a genuine example of an adaptive scientific framework. By recognizing the shift in the features characterizing Darwinism, we can understand its relationship with theories on the origin of life in a non-dogmatic line.
Preventing Retained Surgical Items
Authors: Overman Susan
Published: August 2012

Preventing Retained Surgical Items, AORN, Inc, Ciné‐Med, producer, 2011, DVD, http://cine‐med.com/index.php?nav=aorn&id=1952
Risk Factors Associated With Incorrect Surgical Counts
Authors: Rowlands Aletha
Published: August 2012

Incorrect surgical counts after surgery are a perplexing problem for nurses working in the perioperative environment. To determine factors associated with an incorrect surgical count, this cross‐sectional, correlational study examined explanatory variables (eg, patient and nurse characteristics, intraoperative circumstances, staff involvement) by using data abstracted from perioperative medical records and primary data collected from perioperative nurses. In the final multivariate analysis, six variables were significantly associated with an incorrect surgical count: a higher surgical risk, a lower body mass index, a complicated procedure, an unplanned procedure, an increased number of perioperative personnel involved, and an increased number of specialty teams involved.
Complications of laparoscopic radical prostatectomy–A single institute experience
Authors: Juan Hsu‐Cheng , Yeh Hsin‐Chih , Li Ching‐Chia , Wu Wen‐Jeng , Chou Yii‐Her , Huang Chun‐Hsiung , Huang Shu‐Pin
Published: August 2012

Laparoscopic radical prostatectomy (LRP) is a demanding procedure that requires surgical skill, a long learning curve and significant laparoscopic expertise. We report herein our initial experience with 41 laparoscopic radical prostatectomies to assess all perioperative complications in our initial 5‐year experience. We reviewed retrospectively the case records of 41 patients who underwent laparoscopic radical prostatectomy for clinically localized prostate cancer from 2005 to 2010 at our institution. All abnormal symptoms were developed during the 30 days after the operation. Complications were noted as well as their severity according to the Clavien grading system. No conversion to open surgery was necessary in all cases. The median postoperative hospital stay was 10 days (range 9–16). The median duration of bladder catheterization was 8 days (range 7–35). There was no case of multiple‐organ dysfunction or death. Minor complications constituted 82.6% of all complications. The incidence of severe complications was 17.4%. LRP displayed some advantages over open surgery in the perioperative period. Our complication rates were significantly higher than those indicated in the series previously reported. We found that most complications occurred in the first 30 patients who underwent LRP. We suggest that the surgeons should pay more attention to the difficulties of the procedure.
THE BIRTH OF SHAKESPEARE'S BIRTHPLACE
Authors: Schoch Richard
Published: August 2012

“There is, indeed, little doubt,” the formidable scholar James Orchard Halliwell-Phillipps confidently explained to the Victorian readers of hisOutlines of the Life of Shakespeare,“that the Birth-place did not become one of the incentives for pilgrimage until public attention had been specially directed to it at the time of the Jubilee.” That's broadly true. The earliest reference to the three-gabled, half-timbered house (two houses, originally) on Henley Street in Stratford-upon-Avon as the birthplace of William Shakespeare dates only from the late 1750s, when it was so named in Samuel Winter's town map. During the Stratford Jubilee, which David Garrick organized in 1769, the “small old house,” as the actor's first biographer called it, was fully recognized and promoted as the place where Shakespeare was born. Even so, Halliwell-Phillipps's observation conceals more than it reveals, because there is also little doubt that the dwelling that tradition calls Shakespeare's birthplace did not suddenly acquire that status during the first week of September 1769. The process by which the unremarkable piece of real estate that John Shakespeare purchased sometime in the late sixteenth century was transformed into what Barbara Hodgdon has rightly called the “controlling ideological center” of Shakespeare biography was long, slow, and far from inevitable. That process is the subject of this essay.
“THE MODERN IDEA UNDER AN ANTIQUE FORM”: AESTHETICISM AND THEATRICAL ARCHAEOLOGY IN OSCAR WILDE'SDUCHESS OF PADUA
Authors: Mackie Gregory
Published: August 2012

During his final years in exile, Oscar Wilde derived as much income as he could from selling the rights to his as-yet-unpublished writings. Although at that time he was as pragmatic in his approach to the business of authorship as he had been during the height of his dramatic career in the early 1890s, Wilde nonetheless resisted publishing one of his earliest plays, the 1883 blank-verse tragedyThe Duchess of Padua. In an 1898 letter to Robert Ross, Wilde noted of the play (which was finally produced in 1891) that “The Duchessis unfit for publication—the only one of my works that comes under that category. But there are some good lines in it.” Wilde had not always had such a dim view of his second completed play. Indeed, he once promoted it as “the masterpiece of all my literary work, thechef-d'oeuvreof my youth” and had worked hard to see it produced. Literary history, however, has tended to concur with Wilde's more mature assessment of the play's artistic merits. Katharine Worth, one of the few critics to assess the play in detail, suggests that it “is the one completed play of Wilde's which can scarcely be imagined in a modern performance.” Josephine M. Guy and Ian Small place the play among a group of early works by Wilde that “have been judged by modern critics to be failures.” According to their view,The Duchess“is seen as an embarrassment.” This essay instead regardsThe Duchessas an uneven experiment in both staging aestheticism and late Victorian theatrical “archaeology,” a practice that sought to mount historical dramas with as much accuracy and precision in costume and design as possible. In a letter to Mary Anderson, the American actress whom he hoped would star in the play, Wilde contextualized the spectacle to which he aspired inThe Duchess:“the essence of art is to produce the modern idea under an antique form.”
“HOW MUCH IS A LOAF OF BREAD?”: ASTR PRESIDENTIAL ADDRESS (MONTREAL, 17 NOVEMBER 2011)
Authors: Blair Rhonda
Published: August 2012

Moment no. 1: It's the mid-1970s. I'm in graduate school at the University of Kansas. Ron Willis, a student of Brock's at Iowa in the 1960s and a brilliant, wise man, is teaching his class “The History of the Theatrical Event”; the required texts includeZen and the Art of Motorcycle MaintenanceandThe Crack in the Cosmic Egg(the midseventies were more or less the tail end of the sixties). We begin with the Greeks, and Ron asks, “How much was entry into the theatre?” Of course I'm prepared and know the answer. I jump in: “Two obols.” Then he says, “How much was a loaf of bread?” My head explodes. This was a moment when I got something about not just the economies of theatre, but about its ecology as well—its situatedness. I know my realization is a no-brainer rather than a mind-blower, but for me, given the year and my background, it was germinal.
TRANSLATION AND PERFORMANCE: A PREVIEW OF THEATRE SURVEY'S FIRST WORKING SESSION (NASHVILLE, NOVEMBER 2012)
Authors: Puga Ana Elena
Published: August 2012

I recently translated and then served as dramaturge on the English-language world premiere of Patricia Suárez's Matchmaker (Casamentera), a contemporary Argentine play about the early twentieth-century sex trade in Jewish women imported from Eastern European villages to Buenos Aires brothels. Matchmaker was published in an anthology I edited, Spectacular Bodies, Dangerous Borders: Three New Latin American Plays, along with my translation of The Girls from the 3.5 Floppies (Las chicas del tres y media floppies) by the Mexican playwright Luis Enrique Gutiérrez Ortiz Monasterio (who goes by the acronym LEGOM) and Heather McKay's translation of Passport by the Venezuelan playwright Gustavo Ott. In February 2012, Matchmaker was staged in the Thurber Theatre at The Ohio State University. The production was directed by Lesley Ferris.
Cluster observations of the dusk flank magnetopause near the sash: Ion dynamics and flow‐through reconnection
Authors: Maynard Nelson C. , Farrugia Charles J. , Burke William J. , Ober Daniel M. , Mozer Forrest S. , Rème Henri , Dunlop Malcolm , Siebert Keith D.
Published: August 2012

Compared to the dayside, dynamics on the flanks of the magnetopause are poorly understood. To help bridge this knowledge gap we analyzed Cluster plasma and field measurements acquired during a 90‐min period on 20 November 2003 when Cluster crossed the magnetopause four times in the vicinity of the sash. MHD simulations provide a context for Cluster observations. Crossings were between the magnetosheath and an S‐shaped plasma sheet, rather than to the open‐field lobes of the magnetotail. Cluster encountered two regions of MHD‐breaking differences between perpendicular ion velocities andE × B convection. Ion adiabatic expansion parameter (δi) calculations show that ion gyrotropy was not broken during an episode of strong Alfvén wave activity in the magnetosheath. However, gyrotropy was broken (δi> 1) during the fourth magnetopause crossing. In the magnetosheath, ion guiding‐center motion was maintained but inertial effects associated with temporally varying electric fields are probable sources of velocity differences. Regarding the magnetopause crossing, the generalized Ohm's law limits possible sources for breaking ion gyrotropy to inertial forces and/or electron pressure gradients associated with a nearby reconnection event. We suggest that Cluster witnessed effects of a temporally varying and spatially limited, flow‐through reconnection event between open mantle field lines from the two polar caps adding new closed flux to the LLBL at the sash. Future modeling of flank dynamics must consider inertial forces as significant drivers at the magnetopause and in the adjacent magnetosheath.
Nonzero azimuthal magnetic fields at the solar source surface: Extraction, model, and implications
Authors: Schulte in den Bäumen Hagen , Cairns Iver H. , Robinson P. A.
Published: August 2012

A recent two‐dimensional (radial distancer and solar longitude ϕ) model for the solar wind is driven using 1 h average data from the Wind spacecraft. We extend the treatment of the Sun's magnetic field in comparison with previous models to allow a nonzero intrinsic azimuthal component Bϕ at the solar source surface, in addition to the radial component Br. We find nonzero azimuthal magnetic fields at the source surface which dominate the variability in B(r, ϕ) at 1 AU and beyond. The averages 〈|Bϕ(Rs)|〉 and 〈|Br(Rs)|〉 inferred over solar cycle 23 were 0.44 ± 0.48 μT (4.4 ± 4.8 mG) and 120 ± 30 μT (1.2 ± 0.3 G) at the photosphere, respectively, where Rs equals one solar radius. While the surface magnetic field is closely radial on average as expected, it is sometimes over 20° from radial. Both Bϕ and Br vary smoothly on periods of order of a day, with evidence for relatively narrow current sheets, and vary differently with the solar cycle: Br(Rs) is correlated with the sunspot number while Bϕ(Rs) has a two‐level behavior. The typical fields |Br(Rs)| are consistent with previous estimates. This consistency, the finding of a linear relation between the data‐smoothing time period and the average transition time for each component and other arguments support the contention that theBϕ(Rs) fields found are intrinsic. Our results and model can account naturally for non‐Parker‐like magnetic field directions at 1 AU and allr above the source surface.
Bright polar mesospheric clouds formed by main engine exhaust from the space shuttle's final launch
Authors: Stevens Michael H. , Lossow Stefan , Fiedler Jens , Baumgarten Gerd , Lübken Franz‐Josef , Hallgren Kristofer , Hartogh Paul , Randall Cora E. , Lumpe Jerry , Bailey Scott M. , Niciejewski R. , Meier R. R. , Plane John M. C. , Kochenash Andrew J. , Murtagh Donal P. , Englert Christoph R.
Published: August 2012

The space shuttle launched for the last time on 8 July 2011. As with most shuttle launches, the three main engines injected about 350 t of water vapor between 100 and 115 km off the east coast of the United States during its ascent to orbit. We follow the motion of this exhaust with a variety of satellite and ground‐based data sets and find that (1) the shuttle water vapor plume spread out horizontally in all directions over a distance of 3000 to 4000 km in 18 h, (2) a portion of the plume reached northern Europe in 21 h to form polar mesospheric clouds (PMCs) that are brighter than over 99% of all PMCs observed in that region, and (3) the observed altitude dependence of the particle size is reversed with larger particles above smaller particles. We use a one‐dimensional cloud formation model initialized with predictions of a plume diffusion model to simulate the unusually bright PMCs. We find that eddy mixing can move the plume water vapor down to the mesopause near 90 km where ice particles can form. If the eddy diffusion coefficient is 400 to 1000 m2/s, the predicted integrated cloud brightness is in agreement with both satellite and ground‐based observations of the shuttle PMCs. The propellant mass of the shuttle is about 20% of that from all vehicles launched during the northern 2011 PMC season. We suggest that the brightest PMC population near 70°N is formed by space traffic exhaust.
Inference of permeability distribution from injection‐induced discrete microseismic events with kernel density estimation and ensemble Kalman filter
Authors: Tarrahi Mohammadali , Jafarpour Behnam
Published: August 2012

Hydraulic stimulation of subsurface rocks is performed in developing geothermal and hydrocarbon reservoirs to create permeable zones and enhance flow and transport in low‐permeability formations. Borehole fluid injection often induces measurable microearthquakes (MEQs). While the nature and source of the processes that lead to triggering of these events is yet to be fully understood, a major hypothesis has linked these events to an increase in pore pressure that decreases the effective compressional stress and causes sliding along preexisting cracks. Based on this hypothesis, the distribution of the resulting microseismicity clouds can be viewed as monitoring data that carry important information about the spatial distribution of hydraulic rock properties. However, integration of fluid‐induced microseismicity events into prior rock permeability distributions is complicated by the discrete nature of the MEQ events, which is not amenable to well‐established inversion methods. We use kernel density estimation to first interpret the MEQ data events as continuous seismicity density measurements and, subsequently, assimilate them to estimate rock permeability distribution. We apply the ensemble Kalman filter (EnKF) for microseimic data integration where we update a prior ensemble of permeability distributions to obtain a new set of calibrated models for prediction. The EnKF offers several advantages for this application, including the ensemble formulation for uncertainty assessment, convenient gradient‐free implementation, and the flexibility to incorporate various failure mechanisms and additional data types. Using several numerical experiments, we illustrate the suitability of the proposed approach for characterization of reservoir hydraulic properties from discrete MEQ monitoring measurements.
The biological roles of glutaredoxins
Authors: Ströher Elke , Millar A. Harvey
Published: August 2012

Grxs (glutaredoxins) are small ubiquitous redox enzymes. They are generally involved in the reduction of oxidative modifications using glutathione. Grxs are not only able to reduce protein disulfides and the low-molecular-mass antioxidant dehydroascorbate, but also represent the major enzyme class responsible for deglutathionylation reactions. Functional proteomics, including interaction studies, comparative activity measurements using heterologous proteins and structural analysis are combined to provide important insights into the crucial function of Grxs in cellular redox networks. Summarizing the current understanding of Grxs, with a special focus on organelle-localized members across species, genus and kingdom boundaries (including cyanobacteria, plants, bacteria, yeast and humans) lead to two different classifications, one according to sequence structure that gives insights into the diversification of Grxs, and another according to function within the cell that provides a basis for assessing the different roles of Grxs.
Generation and characterization of non-competitive furin-inhibiting nanobodies
Authors: Zhu Jingjing , Declercq Jeroen , Roucourt Bart , Ghassabeh Gholamreza H. , Meulemans Sandra , Kinne Jörg , David Guido , Vermorken Alphons J. M. , Van de Ven Wim J. M. , Lindberg Iris , Muyldermans Serge , Creemers John W. M.
Published: August 2012

The PC (proprotein convertase) furin cleaves a large variety of proproteins and hence plays a major role in many pathologies. Therefore furin inhibition might be a good strategy for therapeutic intervention, and several furin inhibitors have been generated, although none are entirely furin-specific. To reduce potential side effects caused by cross-reactivity with other proteases, dromedary heavy-chain-derived nanobodies against catalytically active furin were developed as specific furin inhibitors. The nanobodies bound only to furin but not to other PCs. Upon overexpression in cell lines, they inhibited the cleavage of two different furin substrates, TGFβ (transforming growth factor β) and GPC3 (glypican 3). Purified nanobodies could inhibit the cleavage of diphtheria toxin into its enzymatically active A fragment, but did not inhibit cleavage of a small synthetic peptide-based substrate, suggesting a mode-of-action based on steric hindrance. The dissociation constant of purified nanobody 14 is in the nanomolar range. The nanobodies were non-competitive inhibitors with an inhibitory constant in the micromolar range as demonstrated by Dixon plot. Furthermore, anti-furin nanobodies could protect HEK (human embryonic kidney)-293T cells from diphtheria-toxin-induced cytotoxicity as efficiently as the PC inhibitor nona-D-arginine. In conclusion, these antibody-based single-domain nanobodies represent the first generation of highly specific non-competitive furin inhibitors.
Cell polarity and asymmetric cell division: the C. elegans early embryo
Authors: Noatynska Anna , Gotta Monica
Published: August 2012

Cell polarity is crucial for many functions including cell migration, tissue organization and asymmetric cell division. In animal cells, cell polarity is controlled by the highly conserved PAR (PARtitioning defective) proteins. par genes have been identified in Caenorhabditis elegans in screens for maternal lethal mutations that disrupt cytoplasmic partitioning and asymmetric division. Although PAR proteins were identified more than 20 years ago, our understanding on how they regulate polarity and how they are regulated is still incomplete. In this chapter we review our knowledge of the processes of cell polarity establishment and maintenance, and asymmetric cell division in the early C. elegans embryo. We discuss recent findings that highlight new players in cell polarity and/or reveal the molecular details on how PAR proteins regulate polarity processes.
The Hippo pathway: key interaction and catalytic domains in organ growth control, stem cell self-renewal and tissue regeneration
Authors: Cherrett Claire , Furutani-Seiki Makoto , Bagby Stefan
Published: August 2012

The Hippo pathway is a conserved pathway that interconnects with several other pathways to regulate organ growth, tissue homoeostasis and regeneration, and stem cell self-renewal. This pathway is unique in its capacity to orchestrate multiple processes, from sensing to execution, necessary for organ expansion. Activation of the Hippo pathway core kinase cassette leads to cytoplasmic sequestration of the nuclear effectors YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif), consequently disabling their transcriptional co-activation function. Components upstream of the core kinase cassette have not been well understood, especially in vertebrates, but are gradually being elucidated and include cell polarity and cell adhesion proteins.
Change of Beclin‐1 dependent on ATP, [Ca2+]i and MMP in PC12 cells following oxygen‐glucose deprivation‐reoxygenation injury
Authors: Mo Zhentao , Fang Yongqi , He Yuping , Ke Xuehong
Published: August 2012

Autophagy is usually up‐regulated to provide more ATP in response to starvation or OGD (oxygen‐glucose deprivation), but the relationship between autophagy and ATP, [Ca2+]i (intracellular free Ca2+ concentration) or MMP (mitochondrial membrane potential) during reoxygenation is not yet fully clear. The role of autophagy is unknown in PC12 cells subjected to 2 h OGD with different time points of reoxygenation. In the present study, we showed that Beclin‐1 was up‐regulated beginning at 0 h reoxygenation peaking at 24 h and lasting for 48 h. Cell viability was decreased from 0 to 48 h reoxygenation, reaching its minimum at 10 h reoxygenation. ATP was decreased from 0 to 10 h reoxygenation, reaching its minimum at 4 h reoxygenation. A significant negative correlation was observed between ATP and Beclin‐1 (r = −0.61, P<0.05) at 0 h reoxygenation, but ATP was not significant related (r = 0.24, P>0.05) to Beclin‐1 at 24 h reoxygenation. Besides, Nimodipine, a calcium antagonist, significantly reduced [Ca2+]i and Beclin‐1, but increased MMP in OGD/R‐treated cells. At 24 h reoxygenation, Beclin‐1 expression reached its maximum, cell viability continued to increase, and ATP was higher than that before OGD. These results suggest that energy metabolism dysfunction can induce autophagy during OGD in PC12 cells. Increased [Ca2+]i and decreased MMP may induce autophagy during reoxygenation in PC12 cells. Autophagy may be a protective effect on PC12 cells treated with different time points of reoxygenation after 2 h OGD.
Crosstalk in x-ray framing cameras: Effect on voltage, gain, and timing (invited)
Authors: Benedetti L. R. , Bell P. M. , Bradley D. K. , Brown C. G. , Glenn S. M. , Heeter R. , Holder J. P. , Izumi N. , Khan S. F. , Lacaille G. , Simanovskaia N. , Smalyuk V. A. , Thomas R.
Published: August 2012

We present evidence that electromagnetic crosstalk between independent strips in gated x-ray framing cameras can affect relative gains by up to an order of magnitude and gate arrival times up to tens of picoseconds when strip separation times are less then ∼1 ns. Crosstalk is observed by multiple methods, and it is confirmed by direct measurements of voltage on the active surface of the detector and also by indirect voltage monitors in routine operation. The voltage measurements confirm that crosstalk is produced not only in the active regions of the microchannel plate, but also along the entire input path of the voltage pulses.
Infrared absorption of trans-1-chloromethylallyl and trans-1-methylallyl radicals produced in photochemical reactions of trans-1,3-butadiene and Cℓ2 in solid para-hydrogen
Authors: Bahou Mohammed , Wu Jen-Yu , Tanaka Keiichi , Lee Yuan-Pern
Published: August 2012

The reactions of chlorine and hydrogen atoms with trans-1,3-butadiene in solid para-hydrogen (p-H2) were investigated with infrared (IR) absorption spectra. When a p-H2 matrix containing Cℓ2 and trans-1,3-butadiene was irradiated with ultraviolet light at 365 nm, intense lines at 650.3, 809.0, 962.2, 1240.6 cm−1, and several weaker ones due to the trans-1-chloromethylallyl radical, •(CH2CHCH)CH2Cℓ, appeared. Observed wavenumbers and relative intensities agree with the anharmonic vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++g(2d, 2p) method. That the Cℓ atom adds primarily to the terminal carbon atom of trans-1,3-butadiene is in agreement with the path of minimum energy predicted theoretically, but in contrast to the reaction of Cℓ + propene in solid p-H2 [J. Amicangelo and Y.-P. Lee, J. Phys. Chem. Lett. 1, 2956 (2010)]10.1021/jz101119b in which the addition of Cℓ to the central C atom is favored, likely through steric effects in a p-H2 matrix. A second set of lines, intense at 781.6, 957.9, 1433.6, 2968.8, 3023.5, 3107.3 cm−1, were observed when the UV-irradiated Cℓ2/trans-1,3-butadiene/p-H2 matrix was further irradiated with IR light from a SiC source. These lines are assigned to the trans-1-methylallyl radical, •(CH2CHCH)CH3, produced from reaction of 1,3-butadiene with a H atom resulted from the reaction of Cℓ atoms with solid p-H2 exposed to IR radiation.
Fully synchronous solutions and the synchronization phase transition for the finite-N Kuramoto model
Authors: Bronski Jared C. , DeVille Lee , Jip Park Moon
Published: August 2012

We present a detailed analysis of the stability of phase-locked solutions to the Kuramoto system of oscillators. We derive an analytical expression counting the dimension of the unstable manifold associated to a given stationary solution. From this we are able to derive a number of consequences, including analytic expressions for the first and last frequency vectors to phase-lock, upper and lower bounds on the probability that a randomly chosen frequency vector will phase-lock, and very sharp results on the large N limit of this model. One of the surprises in this calculation is that for frequencies that are Gaussian distributed, the correct scaling for full synchrony is not the one commonly studied in the literature; rather, there is a logarithmic correction to the scaling which is related to the extremal value statistics of the random frequency vector.
The resonant radio-frequency magnetic probe tuned by coaxial cable
Authors: Sun B. , Huo W. G. , Ding Z. F.
Published: August 2012

In this paper, the resonant rf magnetic probe is upgraded by replacing the rotary capacitor in the old version with the series-connected coaxial cable. The numerical calculation and the measurement with the prototype probe show that the rf magnetic probe can achieve resonance at a middle length of the series-connected coaxial cable. The good electrical symmetry of the new rf magnetic probe is ensured by both the identity of series-connected coaxial cables and the new structure of the primary winding. Practical measurements conduced on an rf inductively coupled plasma source demonstrate that performances of the new rf magnetic probe are good.
Analytic calculation of second-order electric response properties with the normalized elimination of the small component (NESC) method
Authors: Zou Wenli , Filatov Michael , Cremer Dieter
Published: August 2012

Analytic second derivatives of the relativistic energy for the calculation of electric response properties are derived utilizing the normalized elimination of the small component (NESC) method. Explicit formulas are given for electric static dipole polarizabilities and infrared intensities by starting at the NESC representation of electric dipole moments. The analytic derivatives are implemented in an existing NESC program and applied to calculate dipole moments, polarizabilities, and the infrared spectra of gold- and mercury-containing molecules as well as some actinide molecules. Comparison with experiment reveals the accuracy of NESC second order electric response properties.