bluuebunny/crossref_metadata_2025 huggingface dataset:
TWO-DIMENSIONAL ANALYTICAL MODELING AND SIMULATION OF RETROGRADE DOPED HMG MOSFET
Authors: GUPTA R. S. , GOEL KIRTI , GUPTA MRIDULA , SAXENA MANOJ
Published: August 2005

A novel device architecture, Retrograde doped HMG (Hetero-Material Gate) MOSFET is presented which combines the advantages of an epitaxial layer in the channel region with the HMG MOSFET. This combination tackles the problems of short channel effects (SCEs), hot electron effects and gate transport efficiency in a single structure by reducing threshold voltage and modifying the electric field pattern and surface potential profile along the channel. The expression for the 2-D potential profile in the channel has been derived. The results of surface potential, electric field and threshold voltage have been plotted and compared with their corresponding simulated results.
ANALYSIS OF GaN HBT STRUCTURES FOR HIGH POWER, HIGH EFFICIENCY MICROWAVE AMPLIFIERS
Authors: KEOGH D. M. , LI J. C. , CONWAY A. M. , QIAO D. , RAYCHAUDHURI S. , ASBECK P. M. , DUPUIS R. D. , FENG M.
Published: August 2005

GaN has become increasingly important for microwave applications up to K a band as a result of its wide band-gap, which provides a high critical breakdown field and good thermal stability, yielding excellent potential for high power and high voltage operation. It is of major interest to understand the device structures that will lead to high efficiency, high power microwave amplifiers. In this paper, we investigate by simulation the microwave performance of InGaN/GaN Heterojunction Bipolar Transistors (HBTs), with proper device geometry to account for the effects of current crowding. We provide an analysis of both emitter-up and collector-up InGaN/GaN HBT structures, based on a distributed HBT model implemented in ADS. We simulate their performance in a fully matched Class B high power amplifier. The results show that an important issue for high power operation is the mismatch between optimum load conditions for peak output power and peak gain, To increase the output impedance, it is important to decrease base-collector capacitance, which can be achieved with a collector-up structure. Furthermore, current crowding in the emitter caused by the sheet resistance in the base becomes more important at higher power operation, and is therefore a key design consideration.
ANALYTICAL MODEL FOR NON-SELF ALIGNED BURIED P-LAYER SiC MESFET
Authors: GUPTA R. S. , AGGARWAL SANDEEP KUMAR , GUPTA RITESH , GUPTA MRIDULA , HALDAR SUBHASIS
Published: August 2005

A new analytical model for saturation region is proposed for buried p-layer 4 H - SiC MESFET considering the effect of B.P. layer. This model provides the static characteristics, small signal parameters and is also extended to predict capacitance-voltage characteristics of the device. The results so obtained are in excellent agreement with experimental data confirming the validity of this model.
INFLUENCE OF THE N-DIFFUSION LAYER ON THE CHANNEL CURRENT AND THE BREAKDOWN VOLTAGE IN 4H-SiC SIT
Authors: CHOI YOUNG CHUL , CHA HO-YOUNG , EASTMAN LESTER F. , SPENCER MICHAEL G.
Published: August 2005

For a recessed gate (RG) silicon carbide ( SiC ) static induction transistor (SIT), an n-diffusion layer technique to maximize a maximum channel current ( I MAX ) and realize an efficient breakdown voltage (BV) was presented. An n-diffusion layer having a doping profile of a Gaussian distribution was formed from the source to the channel region and introduced to elevate the doping concentration of the channel region. Through the simulation of a RG SiC SIT with an n-diffusion layer, it was verified that an n-diffusion layer technique was an excellent way to realize a very small width of a source region ( W s ), resulting in an larger I MAX and a higher BV simultaneously, and it was desirable to employ an n-diffusion layer having a slightly larger junction depth ( X j ) than the depth of a gate trench ( L T ) ( L T < X j < 1.3 L T ) into a RG SiC SIT with a small width of the source region ( W S ≈ 0.5 μ m ).
First Measurement of the Branching Fraction of $e^+ e^- \to B^0 \overline{B}^0$
Authors:   The BABAR Collaboration., Godang Romulus
Published: August 2005

We report the first measurement of the absolute branching fraction [Formula: see text] at the ϒ(4S) resonance using data collected with the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring. The analysis is performed with partial reconstruction of the decay [Formula: see text], where the presence of a signal decay is determined using only the lepton and the soft pion from the D* decay. By reconstructing events with one or two signal decays, we obtain a preliminary result of [Formula: see text]. Our result does not depend on branching fractions of the [Formula: see text] and the D*+ decays, on the individual simulated reconstruction efficiencies, on the ratio of the charged and neutral B meson lifetimes, or on the assumption of isospin symmetry.
Radiative Penguin Decays of B Mesons: Measurements of B → K*γ, $B \to K^*_2(1430)\gamma$, and Search for B0 → ϕγ
Authors:   representing the BABAR Collaboration., Bauer Johannes M.
Published: August 2005

Electromagnetic radiative penguin decays of the B meson were studied with the BABAR detector at SLAC's PEP-II asymmetric-energy B Factory. Branching fractions and isospin asymmetry of the decay B → K*γ, branching fractions of [Formula: see text], and a search for B0 → ϕγ are presented. The decay rates may be enhanced by contributions from non-standard model processes.
B DECAYS ON THE LATTICE AND RESULTS FOR PHENOMENOLOGY
Authors: WINGATE MATTHEW , DAVIES CHRISTINE , GRAY ALAN , GULEZ EMEL , SHIGEMITSU JUNKO , LEPAGE G. PETER
Published: August 2005

Lattice Monte Carlo simulations now include the effects of 2 light sea quarks and 1 strange sea quark through the use of an improved staggered fermion action. Consequently, results important to phenomenology are free of the approximate 10% errors inherent in the quenched approximation. This talk reports on calculations of the B and Bs, decay constants and B → πℓν form factors. Accurate determinations of these quantities will lead to tighter constraints on CKM matrix elements.
MOMENTS OF THE HADRONIC MASS DISTRIBUTION IN SEMILEPTONIC B MESON DECAYS
Authors:   for the CDF II collaboration., FANG HUNG-CHUNG
Published: August 2005

We present a measurement of the first and second moments of the squared-mass distribution of charm hadrons in semileptonic decays of B mesons based on ~ 180 pb-1 of data taken with the CDF II detector at the Fermilab Tevatron. For a minimum lepton momentum of 0.7 GeV/c in the B meson rest frame, we measure the first two moments of the D** → D(*)π component to be [Formula: see text] and [Formula: see text]. Combining these values with known contributions from the D and D* components, we obtain the overall charm hadron moments [Formula: see text] and [Formula: see text] where [Formula: see text] is the spin-averaged D meson mass and the subscript "BR" denotes the uncertainty from the branching ratios used to combine the D, D* and D** components. From these moments we also determine the non-perturbative Heavy Quark Effective Theory parameters Λ and λ1 in the pole and 1S mass schemes.
OBSERVATION OF SEMILEPTONIC B DECAYS INTO ORBITALLY EXCITED D FINAL STATES
Authors:   For the DØ Collaboration., Malik Sudhir
Published: August 2005

Using 250 pb-1 of data collected with the DØ detector in Run II of the Tevatron, the two narrow (L = 1) states, D1(2420) and [Formula: see text] have been observed in semileptonic decays of B mesons. Results on the D*+ π- decay mode are presented including a measurement of the branching fraction of B mesons to these states.
A SEARCH FOR THE DECAY B+ → τ+ντ AT BABAR
Authors:   On behalf of BABAR Collaboration., DATTA MOUSUMI
Published: August 2005

We present a search for the decay B+ → τ+ντ in [Formula: see text] decays recorded with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay [Formula: see text] is selected, and in the recoil a search for B+ → τ+ ντ signal is performed. The τ is identified in the following channels: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. We find no evidence of signal, and we set a preliminary upper limit on the branching fraction of [Formula: see text] at the 90% confidence level (CL). This result is then combined with a statistically independent BABAR search for B+ → τ+ντ to give a combined preliminary limit of [Formula: see text] at 90% CL.
Measurement of Dijet Azimuthal Decorrelations in $p{\bar p}$ Collisions
Authors:   FOR THE DØ COLLABORATION., Begel Michael
Published: August 2005

Correlations in the azimuthal angle between the two largest transverse momentum jets have been measured using the DØ detector in [Formula: see text] collisions at [Formula: see text]. The analysis is based on an inclusive dijet event sample in the central rapidity region corresponding to an integrated luminosity of 150 pb-1. Azimuthal correlations are stronger at larger transverse momenta. These are well-described in NLO pQCD, except at large azimuthal differences where soft effects are significant.
COLLINEAR AND SOFT RESUMMATION IN THE LARGE-X LIMIT
Authors: KIDONAKIS NIKOLAOS
Published: August 2005

I discuss general unified formulas for resumming collinear and soft contributions to QCD hard scattering cross sections at large x. Expansions of the resummed cross sections to next-to-next-to-next-to-leading order are also shown along with applications of the formalism.
TOWARDS A LARGE-NC ESTIMATE OF THE O(p6) CHIRAL LOW ENERGY CONSTANTS
Authors: CIRIGLIANO VINCENZO
Published: August 2005

I discuss recent progress in large-NC inspired determinations of chiral low energy constants of order p6. I illustrate the general method and then describe how it works in the case of the 〈VAP〉 three-point function.
WHAT ARE THE DsJ AND X(3872) PARTICLES?
Authors:   on behalf of the Belle Collaboration., DRUTSKOY A.
Published: August 2005

We report measurements of B decay modes involving the newly discovered DsJ and X(3872) particles. Possible spin-parity and quark content assignments of these new states are discussed. The results are based on a large data sample recorded by the Belle detector at the KEKB e+e- collider.
DESCRIBING RECENTLY DISCOVERED NARROW STATES AS QUARKONIA USING A POTENTIAL MODEL
Authors: RADFORD STANLEY F. , REPKO WAYNE W.
Published: August 2005

We examine to what extent several recently discovered narrow resonances can be interpreted as conventional [Formula: see text] bound states describable using a potential model. In doing so, we use a semirelativistic approach, which includes both the v2/c2 and QCD one-loop corrections to the short distance potential and a long range linear potential together with its scalar and vector v2/c2 spin-dependent terms.
Development of a Super B-Factory Monolithic Active Pixel Detector — the Continuous Acquisition Pixel Prototypes
Authors: Barbero M. , Bozek A. , Browder T. , Fang F. , Hazumi M. , Igarashi A. , Iwaida S. , Kennedy J. , Kent N. , Olsen S. , Palka H. , Rosen M. , Ruckman L. , Stanic S. , Trabelsi K. , Tsuboyama T. , Uchida K. , Varner G.
Published: August 2005

The innermost layer of the Belle silicon vertex detector operates 1.5 cm away from the collision point of the highest luminosity collider in the world. Occupancy in this innermost layer is already 10% and expected to continue increasing with the planned significant luminosity increases. A pair of prototype detectors has been developed to address this problem, based upon the same CMOS camera technology now widely deployed in low-cost consumer devices such as cellular telephones. Problems unique to operating in a high luminosity B-factory environment are discussed. Results from a number of tests are presented, demonstrating the viability of this detector technology.
DESIGN, PREPRODUCTION, AND PERFORMANCE OF THE CDF RUN IIB SILICON DETECTOR
Authors:   for the CDF Run IIb Silicon collaboration., LUJAN PAUL
Published: August 2005

A new silicon detector was designed by the CDF collaboration for Run IIb of the Tevatron at Fermilab. The main building block of the new detector is a "supermodule" or "stave", an innovative, compact and lightweight structure of several readout hybrids and sensors with a bus cable running directly underneath the sensors to carry power, data, and control signals to and from the hybrids. The hybrids use a new, radiation-hard readout chip, the SVX4 chip. A number of SVX4 chips, readout hybrids, sensors, and supermodules were produced and tested in preproduction. The performance (including radiation-hardness) and yield of these components met or exceeded all design goals. The detector design goals, solutions, and performance results are presented.
CRYSTALS FOR HIGH-ENERGY CALORIMETRY IN EXTREME ENVIRONMENTS
Authors: NESSI-TEDALDI FRANCESCA
Published: August 2005

Crystals are used as a homogeneous calorimetric medium in many high-energy physics experiments. For some experiments, performance has to be ensured in very difficult operating conditions, like a high radiation environment, very large particle fluxes, high collision rates, placing constraints on response and readout time. An overview is presented of recent achievements in the field, with particular attention given to the performance of Lead Tungstate (PWO) crystals exposed to high particle fluxes.
A SCINTILLATOR BASED MUON DETECTOR FOR THE LINEAR COLLIDER
Authors:   on behalf of the Scintillator Based Muon Collaboration: The Scintillator-Based Muon Collaboration. Fermilab: Alan Bross, H. Eugene Fisk (Co-contact Person), Kurt Krempetz, Caroline Milstene, Adam Para, Oleg Prokofiev, Ray Stefanski; Northern Illinois University: Gerald Blazey, Dhiman Chakraborty, Alexandre Dychkant, David Hedin, Arthur Maciel; University of Notre Dame: Mitchell Wayne; Rice University: B. Paul Padley, Mikhail Matveev, Jabus Roberts; University of California, Davis: Mani Tripathi, Richard Br, KARCHIN PAUL E.
Published: August 2005

The requirements for a linear collider muon detector are discussed and a solution is presented based on solid scintillating strips with embedded wavelength shifting optical fibers. Multi-anode photo-multiplier tubes are a good candidate for photon detection. Their single photo-electron response can be calibrated using fast pulses from light-emitting diodes.
6D IONIZATION MUON COOLING WITH TABLETOP RINGS
Authors: SUMMERS D. J. , BRACKER S. B. , CREMALDI L. M. , GODANG R. , CLINE D. B. , GARREN A. A. , HANSON G. G. , KLIER A. , KAHN S. A. , KIRK H. G. , PALMER R. B.
Published: August 2005

Progress on six dimensional ionization muon cooling with relatively small rings of magnets is described. Lattices being explored include scaling sector cyclotrons with edge focusing and strong focusing, fixed field alternating gradient (FFAG) rings. Ionization cooling is provided by high pressure hydrogen gas which removes both transverse and longitudinal momentum. Lost longitudinal momentum is replaced using radio frequency (RF) cavities, giving a net transverse emittance reduction. The longer path length in the hydrogen of higher momentum muons decreases longitudinal emittance at the expense of transverse emittance. Thus emittance exchange allows these rings to cool in all six dimensions and not just transversely. Alternatively, if the RF is located after the ring, it may be possible to cool the muons by stopping them as they spiral adiabatically into a central swarm. As p → 0, Δp → 0. The resulting cooled muons can lead to an intense muon beam which could be a source for neutrino factories or muon colliders.
A NEW SCALABLE MULTI-NODE EVENT LOGGING SYSTEM FOR BABAR
Authors:   For the BaBar Computing Group., HAMILTON JAMES A. , LUITZ STEFFEN
Published: August 2005

The BaBar experiment is currently operating near the rate limit of its ability to log event data to disk and tape using the existing hardware and software systems. Consequently we have chosen to design and implement a new system for logging event data. The new system is designed to be scalable, so that the data rate can be increased by adding systems at one of three levels. It also has the property that data can be logged at almost unlimited burst rates without introducing dead time. The key to these features lies in the use of many nodes within the level three trigger system of BaBar. This allows the events to first be logged to local disks within the trigger system, and then later to be merged to any of multiple merge servers in non-real-time.
WHAT YOUR NEXT EXPERIMENT'S DATA WILL LOOK LIKE: EVENT STORES IN THE LARGE HADRON COLLIDER ERA
Authors: MALON DAVID
Published: August 2005

Each new generation of collider experiments confronts the challenge of delivering an event store having at least the performance and functionality of current-generation stores, in the presence of an order of magnitude more data and new computing paradigms (object orientation just a few years ago; grid and service-based computing today). The ATLAS experiment at the Large Hadron Collider, for example, will produce 1.6-megabyte events at 200 Hz–an annual raw data volume of 3.2 petabytes. With derived and simulated data, the total volume may approach 10 petabytes per year.

Scale, however, is not the only challenge. In the Large Hadron Collider (LHC) experiments, the preponderance of computing power will come from outside the host laboratory. More significantly, no single site will host a complete copy of the event store–data will be distributed, not simply replicated for convenience, and many physics analyses will routinely require distributed (grid) computing.

This paper uses the emerging ATLAS computing model to provide a glimpse of how next-generation event stores are taking shape, touching on key issues in navigation, distribution, scale, coherence, data models and representation, metadata infrastructure, and the role(s) of databases in event store management.
TRANSITIONS FROM REGULAR TO CHAOTIC VIBRATIONS OF SPHERICAL AND CONICAL AXIALLY-SYMMETRIC SHELLS
Authors: AWREJCEWICZ J. , KRYSKO V. A. , SHCHEKATUROVA T. V.
Published: August 2005

By the variational principle, the chaotic vibrations of deterministic geometrically nonlinear elastic spherical and conical axially symmetric shells with non-homogeneous thickness subjected to a transversal harmonic load are analyzed. The material of the shells is assumed to be isotropic and of the Hookean type. Inertial forces tangent to the averaged surface and inertia of rotation of the cross-section are neglected. By the Ritz procedure, the original PDEs are transferred to the ODEs (Cauchy problem), which are then solved by the fourth-order Runge–Kutta method. In the numerical studies, scenarios of transitions from harmonic to chaotic states for vibrations of flexible spherical and conical shells are detected. Various vibrational states for different combinations of the following control parameters: shell's deflection arrow, the amplitude and frequency of the exciting force, number of modes considered, boundary conditions, and the thickness and shape of the shell cross-section are studied. By adjusting the above parameters, we can detect the transition of a continuous system to the lumped one, and the transition from the harmonic to chaotic vibrations.
AXISYMMETRIC VIBRATION OF POLAR ORTHOTROPIC CIRCULAR PLATES OF QUADRATICALLY VARYING THICKNESS RESTING ON ELASTIC FOUNDATION
Authors: BHARDWAJ N. , GUPTA A. P.
Published: August 2005

This paper is concerned with the axisymmetric vibration problem of polar orthotropic circular plates of quadratically varying thickness and resting on an elastic foundation. The problem is solved by using the Rayleigh–Ritz method with boundary characteristic orthonormal polynomials for approximating the deflection function. Numerical results are computed for frequencies, nodal radii and mode shapes. Three-dimensional graphs are also plotted for the first four normal modes of axisymmetric vibration of plates with free, simply-supported and clamped edge conditions for various values of taper, orthotropy and foundation parameters.
AGGREGATED RATIO ANALYSIS IN DEA
Authors: WU DESHENG , LIANG LIANG , HUANG ZHIMIN , LI SUSAN X.
Published: August 2005

This paper proposes an aggregated ratio analysis model which can be utilized to evaluate relative efficiency of decision making units (DMUs). We show that our proposed ratio model is equivalent to the CCR DEA model. This equivalence property offers a great deal of opportunities for DEA to be interpreted and applied in different ways. Our model also offers an insight into the frontier analysis. Whether a DMU is on the frontier or efficient frontier can be informed by using our aggregated ratio analysis. Several results developed in the paper are coincident with that in the literature.
ASSESSING FINANCIAL RISK TOLERANCE OF PORTFOLIO INVESTORS USING DATA ENVELOPMENT ANALYSIS
Authors: ARDEHALI PARISA HOSSEINI , PARADI JOSEPH C. , ASMILD METTE
Published: August 2005

For some investors their own personal investment counsellors address their investment strategy; for others automated means are used. To protect investors, the Canadian Government has enacted the "Know Your Client" Act requiring that all investment dealers and vendors of securities must know their clients and advise them on the appropriate investment strategy. This paper uses Data Envelopment Analysis (DEA) in a novel manner by applying it to a large data set of answers to a number of psychological questions. A Slacks Based Model was used to estimate investor risk tolerance. The model analyses the risk profile of the investor and can be used as a guide to match the risk rating of the investment vehicles for the client. Statistical comparisons were also carried out to show how risk tolerance relates to various demographic variables. Finally, the DEA results were validated through comparisons with the commercial system already in use.
Enduring Effects for Cognitive Behavior Therapy in the Treatment of Depression and Anxiety
Authors: Hollon Steven D. , Stewart Michael O. , Strunk Daniel
Published: August 2005

Recent studies suggest that cognitive and behavioral interventions have enduring effects that reduce risk for subsequent symptom return following treatment termination. These enduring effects have been most clearly demonstrated with respect to depression and the anxiety disorders. It remains unclear whether these effects are a consequence of the amelioration of the causal processes that generate risk or the introduction of compensatory strategies that offset them and whether these effects reflect the mobilization of cognitive or other mechanisms. No such enduring effects have been observed for the psychoactive medications, which appear to be largely palliative in nature. Other psychosocial interventions remain largely untested, although claims that they produce lasting change have long been made. Whether such enduring effects extend to other disorders remains to be seen, but the capacity to reduce risk following treatment termination is one of the major benefits provided by the cognitive and behavioral interventions with respect to the treatment of depression and the anxiety disorders.
Follistatin attenuates early liver fibrosis: effects on hepatic stellate cell activation and hepatocyte apoptosis
Authors: Patella Shane , Phillips David J. , Tchongue Jorge , de Kretser David M. , Sievert William
Published: August 2005

Activin A, a member of the transforming growth factor-β superfamily, is constitutively expressed in hepatocytes and regulates liver mass through tonic inhibition of hepatocyte DNA synthesis. Follistatin is the main biological inhibitor of activin bioactivity. These molecules may be involved in hepatic fibrogenesis, although defined roles remain unclear. We studied activin and follistatin gene and protein expression in cultured rat hepatic stellate cells (HSCs) and in rats given CCl4 for 8 wk and examined the effect of follistatin administration on the development of hepatic fibrosis. In activated HSCs, activin mRNA was upregulated with high expression levels, whereas follistatin mRNA expression was unchanged from baseline. Activin A expression in normal lobular hepatocytes redistributed to periseptal hepatocytes and smooth muscle actin-positive HSCs in the fibrotic liver. A 32% reduction in fibrosis, maximal at week 4, occurred in CCl4-exposed rats treated with follistatin. Hepatocyte apoptosis decreased by 87% and was maximal at week 4 during follistatin treatment. In conclusion, activin is produced by activated HSCs in vitro and in vivo. Absence of simultaneous upregulation of follistatin gene expression in HSCs suggests that HSC-derived activin is biologically active and unopposed by follistatin. Our in vivo and in vitro results demonstrate that activin-mediated events contribute to hepatic fibrogenesis and that follistatin attenuates early events in fibrogenesis by constraining HSC proliferation and inhibiting hepatocyte apoptosis.
Behavior of the Position Vestibular Pause (PVP) Interneurons of the Vestibuloocular Reflex During Head-Free Gaze Shifts in the Monkey
Authors: Fuchs Albert F. , Ling Leo , Phillips James O.
Published: August 2005

Most behavioral studies indicate that the efficacy (gain) of the vestibuloocular reflex (VOR) in primates is modulated during the voluntary head movements that accompany large shifts in the direction of gaze. However, the timing and degree of this modulation is the subject of some debate. The neurophysiological substrate for this apparent gain reduction has been sought in the behavior of the type I position vestibular pause (PVP) neuron, a well-known type of interneuron in the direct VOR pathway. With the head fixed, PVPs increase their firing rates with contraversive eye position and with ipsiversive passive head rotation and also cease firing (pause) for the duration of ipsiversive saccades. During head-free ipsiversive gaze shifts, the eyes and head move in the same direction. If the vestibular signal carried by PVPs provides the primary drive for the VOR, the vestibular signal should be present during ipsiversive gaze shifts to the degree that the VOR is present. Of 25 type I PVPs recorded, 21 ceased their discharge for the entire duration of the rapid, eye-saccade component of an ipsiversive gaze shift. The resumption of activity occurred, on average, 13 ms after the end of the saccade. These results suggest that the activity of the vast majority of PVP neurons do not reflect the state of the VOR, but rather PVPs are completely eliminated from participation in the reflex during head-free gaze movements. We conclude that if any modulation of the VOR does exist, it must occur through other, probably longer-latency, pathways.
Orientation-Tuned fMRI Adaptation in Human Visual Cortex
Authors: Fang Fang , Murray Scott O. , Kersten Daniel , He Sheng
Published: August 2005

Adaptation is a general property of almost all neural systems and has been a longstanding tool of psychophysics because of its power to isolate and temporarily reduce the contribution of specific neural populations. Recently, adaptation designs have been extensively applied in functional MRI (fMRI) studies to infer neural selectivity in specific cortical areas. However, there has been considerable variability in the duration of adaptation used in these experiments. In particular, although long-term adaptation has been solidly established in psychophysical and neurophysiological studies, it has been incorporated into few fMRI studies. Furthermore, there has been little validation of fMRI adaptation using stimulus dimensions with well-known adaptive properties (e.g., orientation) and in better understood regions of cortex (e.g., primary visual cortex, V1). We used an event-related fMRI experiment to study long-term orientation adaptation in the human visual cortex. After long-term adaptation to an oriented pattern, the fMRI response in V1, V2, V3/VP, V3A, and V4 to a test stimulus was proportional to the angular difference between the adapting and test stimuli. However, only V3A and V4 showed this response pattern with short-term adaptation. In a separate experiment, we measured behavioral contrast detection thresholds after adaptation and found that the fMRI signal in V1 closely matched the psychophysically derived contrast detection thresholds. Similar to the fMRI results, adaptation induced threshold changes strongly depended on the duration of adaptation. In addition to supporting the existence of adaptable orientation-tuned neurons in human visual cortex, our results show the importance of considering timing parameters in fMRI adaptation experiments.
Serotonin Mediates Learning-Induced Potentiation of Excitability
Authors: Burrell Brian D. , Sahley Christie L.
Published: August 2005

Sensitization potentiates excitability in an interneuron, the S-cell, that is critical for this form of learning in the whole-body shortening reflex of the medicinal leech. Serotonin (5-HT) also increases S-cell excitability, and serotonergic modulation is known to be critical for sensitization of whole-body shortening, suggesting that 5-HT mediates learning-induced enhancement of S-cell excitability. In this paper, the role of 5-HT in mediating sensitization-induced potentiation of S-cell excitability was examined. Potentiation of S-cell excitability by 5-HT was blocked by the 5-HT receptor antagonist methysergide and by intracellular injection of the G-protein inhibitor GDP-β-S, indicating that a metabotropic 5-HT receptor was involved. Bath application of Rp-cAMP, an inhibitor of protein kinase A (PKA), blocked 5-HT-induced potentiation of excitability, whereas db-cAMP, a cAMP analogue that activates PKA, mimicked the potentiating effects of 5-HT on the S-cell. During sensitization of the shortening reflex in semi-intact preparations, methysergide and Rp-cAMP prevented learning-induced potentiation of S-cell excitability, as well as the increase in S-cell activity that normally occurs during sensitization. Furthermore, sensitization-induced increases in the shortening reflex did not occur in preparations treated with methysergide or Rp-cAMP. These results demonstrate that sensitization-induced enhancement of S-cell excitability is mediated by 5-HT and suggests that these changes may contribute to this form of learning.
A Reconfiguration of CaV2 Ca2+ Channel Current and Its Dopaminergic D2 Modulation in Developing Neostriatal Neurons
Authors: Salgado Humberto , Tecuapetla Fatuel , Perez-Rosello Tamara , Perez-Burgos Azucena , Perez-Garci Enrique , Galarraga Elvira , Bargas Jose
Published: August 2005

The modulatory effect of D2 dopamine receptor activation on calcium currents was studied in neostriatal projection neurons at two stages of rat development: postnatal day (PD)14 and PD40. D2-class receptor agonists reduced whole cell calcium currents by about 35% at both stages, and this effect was blocked by the D2 receptor antagonist sulpiride. Nitrendipine partially occluded this modulation at both stages, indicating that modulation of CaV1 channels was present throughout this developmental interval. Nevertheless, modulation of CaV1 channels was significantly larger in PD40 neurons. ω-Conotoxin GVIA occluded most of the Ca2+ current modulation in PD14 neurons. However, this occlusion was greatly decreased in PD40 neurons. ω-Agatoxin TK occluded a great part of the modulation in PD40 neurons but had a negligible effect in PD14 neurons. The data indicate that dopaminergic D2-mediated modulation undergoes a change in target during development: from CaV2.2 to CaV2.1 Ca2+ channels. This change occurred while CaV2.2 channels were being down-regulated and CaV2.1 channels were being up-regulated. Presynaptic modulation mediated by D2 receptors reflected these changes; CaV2.2 type channels were used for release in young animals but very little in mature animals, suggesting that changes took place simultaneously at the somatodendritic and the synaptic membranes.
Anticipating the Effects of Gravity When Intercepting Moving Objects: Differentiating Up and Down Based on Nonvisual Cues
Authors: Senot Patrice , Zago Myrka , Lacquaniti Francesco , McIntyre Joseph
Published: August 2005

Intercepting an object requires a precise estimate of its time of arrival at the interception point (time to contact or “TTC”). It has been proposed that knowledge about gravitational acceleration can be combined with first-order, visual-field information to provide a better estimate of TTC when catching falling objects. In this experiment, we investigated the relative role of visual and nonvisual information on motor-response timing in an interceptive task. Subjects were immersed in a stereoscopic virtual environment and asked to intercept with a virtual racket a ball falling from above or rising from below. The ball moved with different initial velocities and could accelerate, decelerate, or move at a constant speed. Depending on the direction of motion, the acceleration or deceleration of the ball could therefore be congruent or not with the acceleration that would be expected due to the force of gravity acting on the ball. Although the best success rate was observed for balls moving at a constant velocity, we systematically found a cross-effect of ball direction and acceleration on success rate and response timing. Racket motion was triggered on average 25 ms earlier when the ball fell from above than when it rose from below, whatever the ball's true acceleration. As visual-flow information was the same in both cases, this shift indicates an influence of the ball's direction relative to gravity on response timing, consistent with the anticipation of the effects of gravity on the flight of the ball.
An NMDA Receptor/Nitric Oxide Cascade Is Involved in Cerebellar LTD But Is Not Localized to the Parallel Fiber Terminal
Authors: Shin Jung Hoon , Linden David J.
Published: August 2005

Long-term depression (LTD) of the parallel fiber-Purkinje cell synapse in the cerebellum is a cellular model system that has been suggested to underlie certain forms of motor learning. Induction of cerebellar LTD requires a postsynaptic kinase limb involving activation of mGluR1, protein kinase Cα (PKCα), and phosphorylation of ser-880 on the AMPA receptor subunit GluR2. Several lines of evidence have also implicated a complementary phosphatase limb in which N-methyl-d-aspartate (NMDA) receptor-mediated Ca2+ influx activates neuronal nitric oxide synthase (nNOS), the ultimate consequences of which are mediated by nitric oxide (NO), cGMP, and inhibition of postsynaptic protein phosphatases. However, the cellular localization of an NMDA/NO cascade has been complicated by the fact that neither functional NMDA receptors nor nNOS are expressed in Purkinje cells. This has lead to a proposal in which NMDA receptors activate nNOS in parallel fibers. Here, we confirm that pharmacological blockade of NMDA receptor or NO signaling blocks induction of LTD. However, no evidence was found for functional NMDA receptors in parallel fiber terminals: blockade of NMDA receptors did not alter either presynaptic Ca2+ transients or the frequency of miniature excitatory postsynaptic currents. NMDA receptor blockade did abolish a slow depolarization evoked by burst stimulation of parallel fiber-stellate cell synapses. The application of NMDA evoked a Ca2+ transient in stellate cell terminals but not in parallel fiber terminals. These results are consistent with the hypothesis that an NMDA receptor/NO cascade involved in cerebellar LTD is localized to interneurons rather than parallel fibers.
Arm Movements Evoked by Electrical Stimulation in the Motor Cortex of Monkeys
Authors: Graziano Michael S. A. , Aflalo Tyson N. S. , Cooke Dylan F.
Published: August 2005

Electrical stimulation of the motor cortex in monkeys can evoke complex, multijoint movements including movements of the arm and hand. In this study, we examined these movements in detail and tested whether they showed adaptability to differing circumstances such as to a weight added to the hand. Electrical microstimulation was applied to motor cortex using pulse trains of 500-ms duration (matching the approximate duration of a reach). Arm movement was measured using a high-resolution three-dimensional tracking system. Movement latencies averaged 80.2 ms. Speed profiles were typically smooth and bell-shaped, and the peak speed covaried with movement distance. Stimulation generally evoked a specific final hand position. The convergence of the hand from disparate starting positions to a narrow range of final positions was statistically significant for every site tested (91/91). When a weight was fixed to the hand, for some stimulation sites (74%), the evoked movement appeared to compensate for the weight in that the hand was lifted to a similar final location. For other stimulation sites (26%), the weight caused a significant reduction in final hand height. For about one-half of the sites (54%), the variation in movement of each joint appeared to compensate for the variation in the other joints in a manner that stabilized the hand in a restricted region of space. These findings suggest that at least some of the stimulation-evoked movements reflect relatively high-level, adaptable motor plans.
Identification, Structural, and Functional Characterization of a New Early Gene (6A3‐5, 7 kb): Implication in the Proliferation and Differentiation of Smooth Muscle Cells
Authors: Zibara Kazem , Garin Gwenaële , McGregor John L.
Published: August 2005

Arterial smooth muscle cells (SMCs) play a major role in atherosclerosis and restenosis. Differential display was used to compare transcription profiles of synthetic SMCs to proliferating rat cultured SMC line. An isolated cDNA band (6A3‐5) was shown by northern (7 kb) to be upregulated in the proliferating cell line. A rat tissue northern showed differential expression of this gene in different tissues. Using 5’ RACE and screening of a rat brain library, part of the cDNA was cloned and sequenced (5.4 kb). Sequence searches showed important similarities with a new family of transcription factors, bearing ARID motifs. A polyclonal antibody was raised and showed a protein band of 175 kd, which is localized intracellularly. We also showed that 6A3‐5 is upregulated in dedifferentiated SMC (P9) in comparison to contractile SMC ex vivo (P0). This work describes cloning, structural, and functional characterization of a new early gene involved in SMC phenotype modulation.
Proteomic Profiling and Neurodegeneration in West‐Nile‐Virus‐Infected Neurons
Authors: Dhingra V. , Li Q. , Allison A. B. , Stallknecht D. E. , Fu Z. F.
Published: August 2005

West Nile virus, a mosquito‐borne flavivirus, is a human, equine, and avian pathogen. High‐resolution two‐dimensional differential‐gel electrophoresis (2D‐DIGE) was used to characterize protein expression in primary rat neurons and to examine the proteomic profiling to understand the pathogenesis of West‐Nile‐associated meningoencephalitis. Three pH ranges, 3–10, 4–7, and 5–6, were used to analyze the protein spots. The proteins are labeled with fluorescent dyes Cy3 and Cy5 before being separated on the basis of charge and size respectively on a two‐dimensional platform. About 55 proteins showed altered expression levels. These were then subsequently digested and identified by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) analysis using peptide mass fingerprinting and database searching. These cellular proteins could represent distinct roles during infection related to apoptosis. Our findings show that two‐dimensional differential gel electrophoresis combined with mass spectrometry is a powerful approach that permits the identification of proteins whose expression was altered due to West Nile virus infection.
Collection of Human Genomic DNA From Buccal Cells for Genetics Studies: Comparison Between Cytobrush, Mouthwash, and Treated Card
Authors: Mulot Claire , Stücker Isabelle , Clavel Jacqueline , Beaune Philippe , Loriot Marie-Anne
Published: August 2005

Alternative sources such as buccal cells have already been tested for genetic studies and epidemiological investigations. Thirty‐seven volunteers participated in this study to compare cytology brushes, mouthwash, and treated cards for DNA collection. Quantity and quality of DNA and cost and feasibility were assessed. The mean DNA yield at 260 nm was found to be 3.5, 4, and 2.6μg for cytobrushes, mouthwashes, and treated cards, respectively. A second quantification technique by fluorescence showed differences in the DNA yield with 1.1 and 5.2μg for cytobrushes and mouthwash, respectively. All buccal samples allowed isolation of DNA suitable for polymerase chain reaction. According to the procedure of sample collection, the yield and purity of collected DNA, and storage conditions, the use of cytobrush appears to be the more appropriate method for DNA collection. This protocol has been validated and is currently applied in three large‐scale multicentric studies including adults or children.
The Multilevel Cycle of Anthropogenic Zinc
Authors: Graedel T. E. , van Beers Dick , Bertram Marlen , Fuse Kensuke , Gordon Robert B. , Gritsinin Alexander , Harper Ermelinda M. , Kapur Amit , Klee Robert J. , Lifset Reid , Memon Laiq , Spatari Sabrina
Published: August 2005

A comprehensive annual cycle for stocks and flows of zinc, based on data from circa 1994 and incorporating information on extraction, processing, fabrication, use, discard, recycling, and landfilling, was carried out at three discrete governmental unit levels—54 countries and 1 country group (which together comprise essentially all global anthropogenic zinc stocks and flows), nine world regions, and the planet as a whole. All of these cycles are available in an electronic supplement to this article, which thus provides a metadata set on zinc flows for the use of industrial ecology researchers. A “best estimate” global zinc cycle was constructed to resolve aggregation discrepancies. Among the most interesting results are the following: (1) The accumulation ratio, that is, addition to in‐use stock as a function of zinc entering use, is positive and large (2/3 of zinc entering use is added to stock) (country, regional, and global levels); (2) secondary input ratios (fractions of input to fabrication that are from recycled zinc) and domestic recycling percentages (fractions of discarded zinc that are recycled) differ among regions by as much as a factor of six (regional level); (3) worldwide, about 40% of the zinc that was discarded in various forms was recovered and reused or recycled (global level); (4) zinc cycles can usefully be characterized by a set of ratios, including, notably, the utilization efficiency (the ratio of manufacturing waste to manufacturing output: 0.090) and the prompt scrap ratio (new scrap as a fraction of manufacturing input: 0.070) (global level). Because capturable discards are a significant fraction of primary zinc inputs, if a larger proportion of discards were recaptured, extraction requirements would decrease significantly (global level). The results provide a framework for complementary studies in resource stocks, industrial resource utilization, energy consumption, waste management, industrial economics, and environmental impacts.
Rethinking Environmental Performance from a Public Health Perspective: A Comparative Industry Analysis
Authors: Koehler Dinah A. , Bennett Deborah H. , Norris Gregory A. , Spengler John D.
Published: August 2005

To date the most common measures of environmental performance used to compare industries, and by extension firms or facilities, have been quantity of pollution emitted or hazardous waste generated. Discharge information, however, does not necessarily capture potential health effects. We propose an alternative environmental performance measure that includes the public health risks of toxic air emissions extended to industry supply chains using economic input‐output life‐cycle assessment. Cancer risk to the U.S. population was determined by applying a damage function to the Toxic Release Inventory (TRI) as modeled by CalTOX, a multimedia multipathway fate and exposure model. Risks were then translated into social costs using cancer willingness to pay. For a baseline emissions year of 1998, 260 excess cancer cases were calculated for 116 TRI chemicals, dominated by ingestion risk from polycyclic aromatic compounds and dioxins emitted by the primary aluminum and cement industries, respectively. The direct emissions of a small number of industry sectors account for most of the U.S. population cancer risk. For the majority of industry sectors, however, cancer risk per $1 million output is associated with supply chain upstream emissions. Ranking industries by total (direct + upstream) supply chain risk per economic output leads to different conclusions about the relative hazards associated with these industries than a conventional ranking based on emissions per economic output.
Redesigning the Industrial Ecology of the Automobile
Authors: Wells Peter , Orsato Renato J.
Published: August 2005

This article explores the potential of industrial ecology to inform the redesign of an existing industry: that which is concerned with the production, sale, and support of automobiles. In so doing, it brings together the concepts embedded in industrial ecology with issues of economic scale, product design or technology, process technology, and the way in which new combinations of these features can result in an alternative structure for the automotive industry that has the potential to enhance sustainability performance. In so doing, the article advances the general argument that the economic, technical, and spatial organization of production and consumption are co‐determined in a manner that collectively shapes the industrial ecology of an industry. In contradistinction to the prevailing industry, the article then advances the concept of micro factory retailing as an alternative framework for the industry that would result in significantly different performance in terms of industrial ecology.
Managing Febrile Infants
Authors: Cox Elizabeth D. , Smith Maureen A. , Bartell Jessica M.
Published: August 2005

The authors hypothesized that sepsis workup recommendations are associated with practice recommendations published during the physician’s residency. The first published recommendations suggesting sepsis workups for nontoxic, young, febrile infants appeared in pediatric journals from 1975-1980 and in family practice journals from 1981-1987. Data are from the Community Tracking Study (3,272 pediatricians and 2,432 family physicians). “Percentage of sepsis workups recommended” was defined by response to a vignette about the percentage of well-appearing 6-week-old children with a fever of 101°F for whom the physician would recommend a sepsis workup. Multivariable regression with piecewise linear functions evaluated workup recommendations by timing of literature recommendations during residency. Pediatricians recommended sepsis workups 81.6% of the time and family physicians 67.7% (p < .001). Increased recommendations occurred among pediatricians who completed residency from 1975-1980 (p < .05) and among family physicians who completed residency from 1981-1987 (p < .005), when specialty-specific journals published recommendations for sepsis workups for febrile infants. The association between publication of sepsis workup recommendations during a physician’s residency and increased sepsis workup recommendations suggests an unrecognized and enduring impact of such publications.