bluuebunny/crossref_metadata_2025 huggingface dataset:
An Experimental Characterization of Dissolution and Complexation Kinetics in Copper CMP
Authors: Palaparthi Ravichandra , Muldowney Gregory
Published: February 2007

A rigorous method is presented for measuring chemical reaction rates for CMP of copper with a slurry containing an oxidizer and complexing agent. A model reaction network is first proposed that includes copper oxidation/reduction at the wafer surface, liquid-phase copper complexation, and copper oxide film formation. Each reaction is studied in a non-polish environment via experiments specially configured to isolate chemical kinetics from transport effects. Oxidation and reduction are characterized in a rotating-disk electrochemical cell, complexation in a stopped-flow reactor, and oxide formation using Auger electron spectroscopy. Rate constants and reaction orders are determined from the data by applying Tafel analysis for oxidation, the Koutecky-Levich approach for reduction, stirred-tank reactor kinetics for complexation, and boundary layer theory for oxide formation. Oxide composition is found to vary with oxidizer level, offering a concentration- dependent resistance to mass transfer. Results are discussed in the context of an integrated CMP model including contact, kinetics, and transport.
Reduced Gas Phase and Surface Kinetics for Silicon Carbide Epitaxial Growth
Authors: Masi Maurizio , Veneroni Alessandro
Published: February 2007

To increase the SiC surface quality up to electronic grade the deposition of epitaxial layers is still necessary. Unfortunately, this process is very difficult to control both in terms of film composition and of flat area portion of the reactor. Moreover, the traditional deposition process using silane/hydrocarbons/hydrogen mixtures is affected by significant problems related to the nucleation of particulate that significantly limit the lifetime of the deposition chamber. To overcome these problems the addition of hydrochloric acid or directly the use of chlorosilanes or even chlorinated hydrocarbons have been proposed. In that cases the deposition mechanism is still not well established and the proposed mechanisms involve a great number of reactions and species. Here, a sensitivity analysis was performed to reduce the more general mechanism, with the particular aim to select the most important reactions to be lately studied by a fundamental quantum mechanics approach.
Computational Modeling of Silicon Nanoparticle Formation
Authors: Dang Hongyi , Swihart M. T.
Published: February 2007

Particulate contamination formed by reactions of silicon- hydrogen species within silicon chemical vapor deposition processes is an important source of yield loss. On the other hand, intentional synthesis of silicon nanoparticles is of great interest because of the unique properties of nanostructured silicon. Thus, fundamental understanding of the various interconnected mechanisms involved in the particulate formation, such as gas phase and gas-surface phase kinetics and particle size/morphology evolution through nucleation, growth, coagulation and coalescence, is of great value in optimizing these processes. The first part of this work provides a framework for using gas phase kinetic mechanisms produced via automated mechanism generation software for the simulation of silicon nanoparticle formation. The second part focuses on developing a 1.5 dimensional aerosol model for the reaction zone of a laser driven aerosol reactor, which fully couples the silane decomposition chemistry, aerosol dynamics, and the fluid velocity/temperature field. The effects of operating conditions on particle product characteristics were investigated.
Study of Corrosion Properties of PVD Coatings and Electrochemically Deposited Polypyrrole Film on Mild Steel
Authors: Machnikova Eva , Pazderova Martina , Bazzaoui Mohammed , Olysar Karel , Machovic Vladimir , Hackerman Norman
Published: February 2007

Electrochemical synthesis of pyrrole on mild steel substrate was carried out by potentiodynamic and galvanostatic techniques from neutral aqueous sodium tartrate medium. Homogenous and adherent PPy layer was achieved by galvanostatic technique at current density 5 mA cm-2. Basic physical vapor deposition (PVD) coatings (TiN, CrN and DLC) deposited on mild steel were used for comparison of corrosion properties with PPy film. The main problem of PVD coatings in the corrosive media is their porosity. Electrochemical deposition of PPy was applied as a solution for the porosity. PPy film was successfully deposited on PVD coatings by the galvanostatic technique. The protection against corrosion was studied in 3% NaCl solution by several electrochemical methods - measurement of potentiodynamic polarization curves, Tafel plot analysis and EIS method.
An Outgas Free Passivation Technology for Semiconductor Vacuum Chamber using Advanced Anodic Oxidation
Authors: Kawase Yasuhiro , Kitano Masafumi , Mizutani Fumikazu , Morinaga Hitoshi , Shirai Yasuyuki , Ohmi Tadahiro
Published: February 2007

Barrier type anodic oxides on aluminum-magnesium (Al-Mg) alloy in nonaqueous electrolyte solution are found to feature some excellent characteristics. Surface micro roughness is found by far less than that grown in aqueous electrolyte solution. Moisture outgassing from the barrier anodic oxides is very much limited. Even at elevated temperature, the barrier anodic oxides develop no heat cracks. They feature outstanding resistance to corrosive process gases. Anodization of Al-Mg alloys in nonaqueous electrolyte solution will be promising surface passivation of the semiconductor vacuum chambers.
Usefulness of the Instantaneous Mass-charge Ratio for Elucidating the Ions Role in the Stabilization and Dissolution Processes in Prussian Blue Films
Authors: Vicente Francisco , Agrisuelas Jeronimo , Gabrielli Claude , García-Jareño José Juan , Giménez-Romero David , Perrot Hubert , Gregori Joan
Published: February 2007

The conversion process of 'insoluble' Prussian Blue films into the 'soluble' structure has been followed by the simultaneous measurement of current and mass changes during voltammetric experiments and focusing on the possibilities of the use of the instantaneous mass/electrical charge ratio at each potential. A similar procedure was used for the analysis of the mechanism of reduction of Prussian Blue films to the Everitt's Salt form and to follow the partial dissolution of iron species during the oxidation to the Pussian Yellow form. The possibility of covering Prussian Blue films by Nafion membranes which make difficult the transport of anions through it allows to discern the role of anions in the solubilization process of Prussian Blue films.
Effect of Boron on the Corrosion Properties of Al0.5CoCrCuFeNiBx High Entropy Alloys in 1N Sulfuric Acid
Authors: Shih Han Chang , Lee Chien Ping , Chen Y.Y. , Wu C.H. , Hsu C.Y. , Yeh J.W.
Published: February 2007

High entropy alloys are a newly developed family of multi- component alloys composed of several major alloying elements, such as copper, nickel, aluminum, cobalt, chromium, iron, etc. Each element in the alloy system is between 5 at.-% and 35 at.- %. High entropy alloy has a lot of advantages regarding its mechanical, magnetic and electrochemical properties. This study discusses the corrosion resistance of Al0.5CoCrCuFeNiBx alloys with various amounts of boron addition. Surface morphology and EDS analysis confirmed that the addition of boron produced Cr and Fe borides. Therefore the content of Cr in the region besides borides precipitates was very scanty. The anodic polarization curves and electrochemical impedance spectra of Al0.5CoCrCuFeNiBx alloys, obtained in 1 N H2SO4 aqueous solution, clearly indicated that the general corrosion resistance decreases as the amounts of boron increases.
Preliminary Results for a Methanol Fuelled SOFC Tubular Stack with Nanocrystalline 8YSZ Electrolyte
Authors: McPhee William , Holden William , Pusz Jakub , Sammes Nigel
Published: February 2007

This paper presents preliminary result from characterization, development and testing of a nanocrystalline structured 8mol% yttrium stabilized zircona (8YSZ) electrolyte. Bright field TEM images showed a range of particle sizes, upwards of 40 nm. The selected area diffraction pattern indicated the presence of a very fine nanostructure. The crystal structure of the nanocrystalline electrolyte powder was characterized using XRD and was shown to be cubic. Initial electrochemical testing was performed using pellet fuel cells, 31 mm dia by 5 mm, in a custom designed testing rig. This allowed a comparison between standard 8YSZ electrolyte and nano crystalline structured 8YSZ. The initial nano crystalline structured 8YSZ was shown to have a 10% increase in power density at 800 degree C compared to the standard 8YSZ.
Improvements to Test Rig for Laboratory Scale Anode Supported SOFC
Authors: Holden William , McPhee William , Sammes Nigel
Published: February 2007

This work encompasses the design of a rig for the testing of laboratory pellet solid oxide fuel cells (SOFC). The unique feature of this pellet fuel cell test rig is the use of pneumatic actuator to give a simple compressive seal. This facilitates the fast setup of pellet fuel cells containing novel material for evaluation. The various design iterations are presented with reasoning for material and design choices. Initial testing of pellet fuel cells revealed a number of issues that needed addressing. These include current collection, fuel preheating, fuel pressurization cell preparation and elimination of small scale leaks. The design philosophy used to rectify these issues will be presented. To accommodate increased functionality and allow flexibility for different types of SOFC tested, anticipated future design changes will also be discussed.
Synthesis and Characterization of LiNi0.5-xMn1.5-yMx+yO4 for 5V Cathode Material by Mechanochemical Process
Authors: Oh Si Hyoung , Jeon Sang Hoon , Kim Chang Sam , Cho Won Il , Cho Byung Won
Published: February 2007

Recently, the high-voltage nickel-substituted manganese spinel is considered as one of the most promising alternatives for LiCoO2 because it can deliver a high discharge voltage profile (~4.7V) and a large 5V region capacity compared with other candidate materials. In this work, the electrochemical performance of this material was improved by doping with aluminum or chromium through the mechanochemical process. From the previous studies, it was known that the degradation of the high-voltage spinel is very dependent on the existence of Mn3+, which is closely related with formation of inactive LizNi1-zO phase in LiNi0.5Mn1.5O4 spinel. It was observed that highly homogenous precursors with aimed composition can be readily obtained through the mechanochemical process and after an appropriate heat-treatment, high-voltage spinel with a negligible 4V plateau can be easily synthesized using ball- milled powders, which was certified by elemental composition analysis, X-ray diffraction pattern studies, and the electrochemical cycling data.
Rotating Disk Electrode Investigations of Fuel Cell Catalyst Degradation Due to Potential Cycling in Acid Electrolyte
Authors: Swathirajan Swathy , Merzougui Belabbes
Published: February 2007

Fuel cells operated under cyclic conditions in automotive operations are more vulnerable to membrane and electrode material degradation. Degradation of Pt catalyst due to potential cycling was characterized by loss of hydrogen adsorption (HAD) area and shift in the half-wave potential for oxygen reduction at a thin film catalyst rotating disk electrode. Potential cycling between 0 and 1.2 V (RHE) for 500 cycles caused about 20 - 30 % decrease in HAD area for two carbon-supported platinum catalysts. This decrease followed second order kinetics, indicating that the loss of surface area is probably caused by agglomeration of Pt particles due to carbon corrosion. Analysis of oxygen reduction kinetic losses shows an increase in Tafel slope due to potential cycling probably due to a change in the morphology of the carbon support caused by corrosion reactions. Three mechanisms are discussed for the loss of surface area and activity of Pt catalyst due to cycling.
Estimation of β-cell function from the data of the oral glucose tolerance test
Authors: Sakaue Shinji , Ishimaru Shinji , Ikeda Daisuke , Ohtsuka Yoshinori , Honda Toshiro , Suzuki Jun-ichi , Kawakami Yoshikazu , Ishii Jun , Nishimura Masaharu
Published: February 2007

Although a hyperbolic relationship between insulin secretion and insulin sensitivity has been shown, the relationship has been often questioned. We examined the relationship using oral glucose tolerance test (OGTT)-derived indexes. A total of 374 Japanese subjects who had never been given a diagnosis of diabetes underwent a 75-g OGTT. In subjects with normal glucose tolerance (NGT), the ln [insulinogenic index (IGI)] was described by a linear function of ln ( x) ( x, insulin sensitivity index) in regression analysis when the reciprocal of the insulin resistance index in homeostasis model assessment, Matsuda's index, and oral glucose insulin sensitivity index were used as x. Because the 95% confidence interval of the slope of the regression line did not necessarily include −1, the relationships between IGI and x were not always hyperbolic, but power functions IGI × xα = a constant. We thought that IGI × xα was an appropriate β-cell function estimate adjusted by insulin sensitivity and referred to it as β-cell function index (BI). When Matsuda's index was employed as x, the BI values were decreased in subjects without NGT. Log BI had a better correlation with fasting plasma glucose (PG; FPG) and 2-h PG in non-NGT subjects than in NGT subjects. In subjects with any glucose tolerance, log BI was linearly correlated with 1-h PG and glucose spike (the difference between maximum PG and FPG). In conclusion, the relationship between insulin secretion and insulin sensitivity was not always hyperbolic. The BI is a useful tool in the estimation of β-cell function with a mathematical basis.
“Good English without Idiom or Tone”: The Colonial Origins of American Speech
Authors: Longmore Paul K.
Published: February 2007

The interplay between modes of speech and the demographical, geographical, social, and political history of Britain's North American colonies of settlement influenced the linguistic evolution of colonial English speech. By the early to mid-eighteenth century, regional varieties of English emerged that were not only regionally comprehensible but perceived by many observers as homogeneous in contrast to the deep dialectical differences in Britain. Many commentators also declared that Anglophone colonial speech matched metropolitan standard English. As a result, British colonials in North America possessed a national language well before they became “Americans.” This shared manner of speech inadvertently helped to prepare them for independent American nation-hood.
Recombinant Thyrotropin in the Diagnosis of Congenital Hypothyroidism
Authors: Tiosano Dov , Even Lea , Shen Orr Zila , Hochberg Ze’ev
Published: February 2007

Context: A modern approach to congenital hypothyroidism requires a definitive diagnosis of the underlying mechanisms; this can be achieved within the first weeks of life. When uncertainty persists, treatment is commenced, and the definitive diagnosis of congenital hypothyroidism is deferred to the age of 3 yr.

Objectives: The interruption of thyroid replacement treatment is perceived as risky by parents and physicians. The aim of this pilot study was to test the possibility of a definitive diagnosis during thyroid replacement treatment, using stimulation of thyroid tissue by recombinant human (rh)TSH.

Subjects: Eight patients, three boys and five girls, age 5–15 yr (mean, 9.5 ± 3.7 yr), with congenital hypothyroidism that had been diagnosed by the neonatal screening program, and having their diagnosis verified between the ages of 3–4 yr, were reevaluated while on thyroid replacement therapy.

Interventions: Patients received im 0.6 mg/m2 rhTSH on two consecutive days.

Results: rhTSH pharmacokinetics, maximal concentration, t1/2, and area under the curve in children were different as compared with adults. In the patients with intact TSH receptors, free T4 levels decreased after the first and the second injection of rhTSH (P = 0.0137 and P = 0.0149, respectively). All eight children showed identical scintigraphy after rhTSH administration as compared with thyroid replacement withdrawal.

Conclusions: The use of rhTSH is effective for definitive diagnosis of congenital hypothyroidism during thyroid replacement treatment, and no safety issues were encountered.
Neuronal and non-neuronal functions of the AP-3 sorting machinery
Authors: Newell-Litwa Karen , Seong Eunju , Burmeister Margit , Faundez Victor
Published: February 2007

Vesicles selectively exchange lipids, membrane proteins and luminal contents between organelles along the exocytic and endocytic routes. The repertoire of membrane proteins present in these vesicles is crucial for their targeting and function. Vesicle composition is determined at the time of their biogenesis by cytosolic coats. The heterotetrameric protein adaptor protein complex 3 (AP-3), a coat component, participates in the generation of a diverse group of secretory organelles and lysosome-related organelles. Recent work has shed light on the mechanisms that regulate AP-3 and the trafficking pathways controlled by this adaptor. Phenotypic analysis of organisms carrying genetic deficiencies in the AP-3 pathway highlight its role regulating the targeting of lysosomal, melanosomal and synaptic vesicle-specific membrane proteins. Synaptic vesicles from AP-3-deficient mice possess altered levels of neurotransmitter and ion transporters, molecules that ultimately define the type and amount of neurotransmitter stored in these vesicles. These findings reveal a complex picture of how AP-3 functions in multiple tissues, including neuronal tissue, and expose potential links between endocytic sorting mechanisms and the pathogenesis of psychiatric disorders such as schizophrenia.
Wound-induced ATP release and EGF receptor activation in epithelial cells
Authors: Yin Jia , Xu Keping , Zhang Jing , Kumar Ashok , Yu Fu-Shin X.
Published: February 2007

We have shown previously that wounding of human corneal epithelial (HCE) cells resulted in epidermal growth factor receptor (EGFR) transactivation through ectodomain shedding of heparin-binding EGF-like growth factor (HB-EGF). However, the initial signal to trigger these signaling events in response to cell injury remains elusive. In the present study, we investigated the role of ATP released from the injured cells in EGFR transactivation in HCE cells as well as in BEAS 2B cells, a bronchial epithelial cell line. Wounding of epithelial monolayer resulted in the release of ATP into the culture medium. The wound-induced rapid activation of phosphatidylinositol-3-kinase (PI3K) and extracellular signal-regulated kinase (ERK) pathways in HCE cells was attenuated by eliminating extracellular ATP, ADP and adenosine. The nonhydrolyzable ATP analog ATP-γ-S induced rapid and sustained EGFR activation that depended on HB-EGF shedding and ADAM (a disintegrin and metalloproteinase). Targeting pathways leading to HB-EGF shedding and EGFR activation attenuated ATP-γ-S-enhanced closure of small scratch wounds. The purinoceptor antagonist reactive blue 2 decreased wound closure and attenuated ATP-γ-S induced HB-EGF shedding. Taken together, our data suggest that ATP, released upon epithelial injury, acts as an early signal to trigger cell responses including an increase in HB-EGF shedding, subsequent EGFR transactivation and its downstream signaling, resulting in wound healing.
Characterization of alteration products in tephra from Haleakala, Maui: A visible-infrared spectroscopy, Mössbauer spectroscopy, XRD, EMPA and TEM study
Authors: Bishop Janice L. , Schiffman Peter , Murad Enver , Dyar M. Darby , Drief Ahmed , Lane Melissa D.
Published: February 2007

Altered basaltic tephra from Haleakala, Maui, are characterized using multiple techniques in order to identify the minerals formed under a variety of conditions and to understand the soil formation processes here. We collected samples that are representative of typical bulk weathered material in the crater, as well as solfataric alteration in a hydrothermal environment. For this study X-ray diffraction, electron probe microanalysis, scanning electron microscopy and transmission electron microscopy are coupled with spectroscopic techniques including Mössbauer, visible-infrared reflectance, transmission infrared, and thermal infrared emission spectroscopies to analyze these samples. The unaltered tephra are composed of feldspar, glass, pyroxene and olivine. Observed alteration products include Fe oxides, phyllosilicates and sulfates, as well as SAED amorphous Al-Si-bearing material. These samples are potential analogs for altered volcanic material on Mars as the pedogenic influences and contact with plants and animals are minimal. Results from this study may help to determine spectral signatures of these samples that could be used for identification on Mars of the minerals observed here.
Using Structured Games to Teach Early Fraction Concepts to Students Who Are Deaf or Hard of Hearing
Authors: Markey Carmel , Power Desmond J. (Desmond John) , Booker George
Published: February 2007

The study focused on the development of the concept of fractions
in a group of 11- and 12-year-old students who were deaf or hard of
hearing. The approach implemented in the study relied extensively on
the use of games with very little formal instruction. It emphasized the
development of appropriate language to facilitate an understanding of the
notion of fractions through the investigation of concrete materials,
pictorial representations, and interactions between students and
teacher. The progress achieved by means of this approach is reported,
and the implications of developing an understanding of fractions (and
mathematics generally) among students who are deaf or hard of hearing
are noted.
Quadratic unipotent Arthur parameters and residual spectrum of symplectic groups
Authors: Kim Henry H. , Shahidi Freydoon
Published: February 2007

The purpose of this paper is to study certain quadratic unipotent Arthur parameters in the sense of Moeglin and use them to parametrize a part of the residual spectrum of symplectic groups over number fields, coming from the conjugacy class of Borel subgroups. In particular, using certain identities satisfied by local intertwining operators, Arthur's multiplicity formula is established for them which remarkably enough appears by itself in the corresponding residue of the Eisenstein series.
Sections of convex bodies
Authors: Zhang Gaoyong
Published: February 2007

The generalized Busemann-Petty problem asks: If the volume of i -dimensional central section of a centrally symmetric convex body in [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /] is smaller than that of another such body, is the volume of the body also smaller? It is proved that the answer is negative if 2 < i < n . The case of a 2-dimensional section remains open. The proof uses techniques in functional analysis and Radon transforms on Grassmannians. It also requires the notion of an i -intersection body which generalizes the notion of an intersection body. Inequalities among the volumes of projection bodies, polar projection bodies and their central sections are proved. They are related to the maximal slice problem.
On the complement of a generic curve in the projective plane
Authors: Xu Geng
Published: February 2007

Let C be a very generic smooth curve of degree d in the complex projective plane. In this paper, we show that for any curve D in the projective plane that does not contain C , the set C ∩ D contains at least d - 2 distinct points. Moreover, this bound is sharp when d ≥ 3. Our motivation for the study of this problem comes from the problem of hyperbolicity of the complement of a plane curve. As an application of our result, we give another proof of the following fact: if C is a very generic smooth curve of degree d ≥ 5 in the complex projective plane, then the intersection of the complement of C in the projective plane with any plane curve D which does not contain C is hyperbolic.
Sur le théorème de finitude de la cohomologie p -adique d'une variété affine non singulière
Authors: Mebkhout Z.
Published: February 2007

On démontre dans cet article que le Théorème de l'indice pour une classe d'équations différentielles p -adiques sur la droite projective entraîne le Théorème de finitude de la cohomologie p -adique de Monsky-Washnitzer d'une variété affine non singulière. La classe précédente d'équations est contenue dans une classe d'équations où le Théorème de l'indice est aujourd'hui établi.
Complete manifolds with nonnegative Ricci curvature and quadratically nonnegatively curved infinity
Authors: Sha Jiping , Shen Zhongmin
Published: February 2007

In this paper, we study complete Riemannian manifolds with nonnegative Ricci curvature and quadratically nonnegatively curved infinity. We show that M is of finite topological type if it has either maximal volume growth or minimal volume growth.
Classification of varieties with canonical curve section via gaussian maps on canonical curves
Authors: Ciliberto Ciro , Lopez Angelo Felice , Miranda Rick
Published: February 2007

The purpose of this article is to develop further a method to classify varieties X ⊂ [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /] having canonical curve section, using Gaussian map computations. In a previous article we applied these techniques to classify prime Fano threefolds, that is Fano threefolds whose Picard group is generated by the hyperplane bundle. In this article we extend this method and classify Fano threefolds of higher index and Mukai varieties , i.e., varieties of dimension four or more with canonical curve sections. First we determine when the Hilbert scheme [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="02i" /] of such varieties X is nonempty. Moreover, in the case of Picard number one, we prove that [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="03i" /] is irreducible and that the examples of Fano-Iskovskih and Mukai form a dense open subset of smooth points of [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="04i" /].
Localization in equivariant intersection theory and the Bott residue formula
Authors: Edidin Dan , Graham William
Published: February 2007

We prove the localization theorem for torus actions in equivariant intersection theory. Using the theorem we give another proof of the Bott residue formula for Chern numbers of bundles on smooth complete varieties. In addition, our techniques allow us to obtain residue formulas for bundles on a certain class of singular schemes which admit torus actions. This class is rather special, but it includes some interesting examples such as complete intersections and Schubert varieties.
On the cone of curves of an abelian variety
Authors: Bauer Thomas
Published: February 2007

Let X be a smooth projective variety over the complex numbers and let N 1 ( X ) be the real vector space of 1-cycles on X modulo numerical equivalence. As usual denote by NE ( X ) the cone of curves on X , i.e. the convex cone in N 1 ( X ) generated by the effective 1-cycles. One knows by the Cone Theorem [4] that the closed cone of curves [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /]( X ) is rational polyhedral whenever c 1 ( X ) is ample. For varieties X such that c 1 ( X ) is not ample, however, it is in general difficult to determine the structure of [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="02i" /]( X ). The purpose of this paper is to study the cone of curves of abelian varieties. Specifically, the abelian varieties X are determined such that the closed cone [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="03i" /]( X ) is rational polyhedral. The result can also be formulated in terms of the nef cone of X or in terms of the semi-group of effective classes in the Néron-Severi group of X .
On absolute CM-periods, II
Authors: Yoshida Hiroyuki
Published: February 2007

For a CM-field K , Shimura defined the period symbol p K by factorizing periods of abelian varieties with complex multiplication. We define the absolute period symbol g K using division values of the multiple gamma function and conjecture that p K coincides with g K up to the multiplication by algebraic numbers. Taking the action of [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /] into account, we present a refined version of this conjecture. We show that these conjectures are consistently formulated and discuss various numerical examples which support our conjectures strongly.
Existence of simple Jacobian varieties of genus g with rank at least 4 g + 5
Authors: Shioda Tetsuji , Terasoma Tomohide
Published: February 2007

We prove the existence of infinitely many curves of genus g over the rational number field which have absolutely simple Jacobian varieties with Mordell-Weil rank at least 4 g + 5.
Unipotent representations attached to spherical nilpotent orbits
Authors: Huang Jing-Song , Li Jian-Shu
Published: February 2007

A coadjoint nilpotent orbit [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /] of a complex semisimple Lie group G is said to be spherical if it contains an open orbit of a Borel subgroup. We determine when and how to attach unitary representations to such an orbit for the real orthogonal and symplectic groups. Our results actually extend to a larger class of nilpotent coadjoint orbits.
On the growth and stability of real-analytic functions
Authors: Phong D. H. , Stein E. M. , Sturm J. A.
Published: February 2007

This paper addresses the issue of whether integrals of real-analytic functions remain finite under small deformations. An approach based on uniform estimates for certain classes of one-dimensional integrals is introduced. It is powerful enough to recover the stability properties of real integrals in two dimensions which follow from the work of Karpushkin, as well as produce new results in higher dimensions. In dimension three, the new stability results are sharp, as shown by the well-known example of Varchenko.
Brown-Comenetz duality and the Adams spectral sequence
Authors: Mahowald Mark , Rezk Charles
Published: February 2007

We show that the class of p -complete connective spectra with finitely presented cohomology over the Steenrod algebra admits a duality theory related to Brown-Comenetz duality. This construction also produces a full-plane version of the classical Adams spectral sequence for such spectra, which converges to the homotopy groups of a "finite" localization.
Discrete analogues in harmonic analysis, I: ℓ 2 estimates for singular radon transforms
Authors: Stein Elias M. , Wainger Stephen
Published: February 2007

This paper studies the discrete analogues of singular Radon transforms. We prove the ℓ 2 boundedness for those operators that are "quasi-translation-invariant." The approach used is related to the "circle-method" of Hardy and Littlewood, and requires multi-dimensional extensions of Weyl sums and Gauss sums, as well as variants that replace scalar sums by operator sums.
Weight one motivic cohomology and K -theory
Authors: Walker Mark E.
Published: February 2007

We study a filtration of the algebraic K -theory spectrum of a smooth variety whose "layers" ought to give the motivic cohomology groups. The central result is a computation of the weight one layer of the filtration. The computations show that the homotopy groups of the weight one piece coincide with the weight one motivic cohomology groups, thus providing evidence that the filtration is correct. Additionally, a novel filtration of K 0 ( X ) is studied, where X is any quasi-projective variety.
The Gromov-Witten class and a perturbation theory in algebraic geometry
Authors: Mochizuki Takuro
Published: February 2007

We propose a method to construct the virtual fundamental class based on the "Kontsevich principle," i.e., we formulate the notion of quasi manifold structrue and establish a way to obtain the fundamental class from it. Also, we show that there is a natural quasi manifold structure on the moduli stack of stable maps, and thus we arrive at the new construction of the Gromov-Witten class. We also prove the fixed point formula for our Gromov-Witten class.
Spectrum of the Ruelle operator and exponential decay of correlations for open billiard flows
Authors: Stoyanov Luchezar
Published: February 2007

The paper deals with the billiard flow in the exterior of several strictly convex disjoint domains in the plane with smooth boundaries satisfying an additional (visibility) condition. Using a modification of the technique of Dolgopyat, we get spectral estimates for the Ruelle operator related to a Markov family for the nonwandering (trapping) set of the flow similar to those of Dolgopyat in the case of transitive Anosov flows on compact manifolds with smooth jointly non-integrable horocycle foliations. As a consequence, we get exponential decay of correlation for Hölder continuous potentials on the nonwandering set. Combining the spectral estimate for the Ruelle operator with an argument of Pollicott and Sharp, we also derive the existence of a meromorphic continuation of the dynamical zeta function of the billiard flow to a half-plane Re( s ) < h T - ε, where h T is the topological entropy of the billiard flow, and an asymptotic formula with an error term for the number π(λ) of closed orbits of least period λ > 0.
Dynamics of bimeromorphic maps of surfaces
Authors: Diller J. , Favre C.
Published: February 2007

We classify bimeromorphic self-maps f : X [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /] of compact Kähler surfaces X in terms of their actions f *: H 1,1 ( X ) [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="02i "/] on cohomology. We observe that the growth rate of ║ f n *║ is invariant under bimeromorphic conjugacy, and that by conjugating one can always arrange that f n * = f * n . We show that the sequence ║ f n *║ can be bounded, grow linearly, grow quadratically, or grow exponentially. In the first three cases, we show that after conjugating, f is an automorphism virtually isotopic to the identity, f preserves a rational fibration, or f preserves an elliptic fibration, respectively. In the last case, we show that there is a unique (up to scaling) expanding eigenvector θ+ for f *, that θ+ is nef, and that f is bimeromorphically conjugate to an automorphism if and only if θ 2 + = 0. We go on in this case to construct a dynamically natural positive current representing θ+, and we study the growth rate of periodic orbits of f . We conclude by illustrating our results with a particular family of examples.
Polynomial diffeomorphisms of C 2 . VIII: Quasi-expansion
Authors: Bedford Eric , Smillie John
Published: February 2007

We introduce the notion of quasi-expansion in the context of polynomial diffeomorphisms of C 2 . Like hyperbolic diffeomorphisms, quasi-expanding maps have uniformly large multipliers at saddle points. On the other hand, unlike the hyperbolic case, quasi-expanding maps can have tangencies between stable and unstable manifolds. We characterize quasi-expansion in a number of ways and develop some of the structure they possess. Quasi-expansion was motivated by the study of real polynomial diffeomorphisms of maximal entropy, and our study of maximal entropy diffeomorphisms relies on the results of this paper.
Déterminant relatif et la fonction Xi
Authors: Carron Gilles
Published: February 2007

Nous obtenons un analogue de la formule de Weyl (ou plutôt sa version intégrée) pour les domaines non-bornés d'une variété riemannienne complète. Cet asymptotique concerne la fonction de décalage spectral de M. Krein. On donne aussi des formules reliant cette fonction et la ζ-régularisation du déterminant de quelques opérateurs.
On the weak continuity of elliptic operators and applications to potential theory
Authors: Trudinger Neil S. , Wang Xu-Jia
Published: February 2007

In this paper, we establish weak continuity results for quasilinear elliptic and subelliptic operators of divergence form, acting on corresponding classes of subharmonic functions. These results are analogous to our earlier results for fully nonlinear k -Hessian operators. From the weak continuity, we derive various potential theoretic results including capacity estimates, potential estimates and the Wiener criterion for regular boundary points. Our methods make substantial use of Harnack inequalities for solutions.
Minimal disks and two-convex hypersurfaces
Authors: Fraser Ailana M.
Published: February 2007

In this paper we apply an existence theory and estimates on the Morse index of minimal two-spheres and minimal disks with free boundary in two-convex domains in Euclidean space and in manifolds with positive isotropic curvature, to study the topology of two-convex domains.
Weighted pluripotential theory in C N
Authors: Bloom T. , Levenberg N.
Published: February 2007

Let K ⊂ C N be compact and let w be a nonnegative, uppersemicontinuous function on K with { z ∈ K : w ( z ) > 0} nonpluripolar. Let Q := - log w and define the weighted pluricomplex Green function V * K,Q ( z ) = lim sup ζ→ z V K,Q (ζ) where V K,Q ( z ) := sup{ u ( z ): u plurisubharmonic in C N , u ( z ) ≤ log + | z | + C, u ≤ Q on K } ( C depends on u ). If w ≡ 1; i.e., Q ≡ 0, we are in the unweighted case and we write V K := V K ,0 . We prove weighted generalizations of several results in pluripotential theory, and we prove a version of a unique continuation property of maximal psh functions. These results are used to show that if E ⊂ F are compact subsets of C N , then d ( E ) = d ( F ) if and only if V * E = V * F where d ( E ) denotes the transfinite diameter of E .
Bessel identities in the Waldspurger correspondence over a p -adic field
Authors: Baruch Ehud Moshe , Mao Zhengyu
Published: February 2007

In this paper we develop the local theory for a Jacquet's relative trace formula. The local theory is essential to the application of the trace formula: it is an identity of Bessel and relative Bessel distributions. We show that the relative Bessel distribution attached to a distinguished (that is, self contragradient) unitary representation of GL 2 ( k ) where k is a p -adic field is given by a locally integrable function, namely the relative Bessel function. We compute the relative Bessel function for principal series, complementary series and special representations. We also show that the Bessel distributions associated to unitary irreducible admissible representations of the double covers of GL 2 ( k ) and SL 2 ( k ) are given by a locally integrable Bessel functions. We compute these Bessel functions for principal series, complementary series and special representations. Finally, we obtain the Waldspurger correspondence via Bessel identities between relative Bessel functions on GL 2 ( k ) and Bessel functions on the double cover of SL 2 ( k ). The Bessel identity also implies the identity between Bessel and relative Bessel distributions.
Every rationally connected variety over the function field of a curve has a rational point
Authors: De Jong A. J. , Starr J.
Published: February 2007

In a paper from 1992, Kollár, Miyaoka and Mori posed the following question: Given a proper flat morphism f : P → X with target a nonsingular curve and whose geometric generic fiber is rationally-connected, does it follow that f admits a regular section? In the case that the ground field is an algebraically-closed field of characteristic zero, this was answered affirmatively by Graber, Harris, and Starr using a topological argument. We prove that f admits a regular section when the ground field is an algebraically-closed field of arbitrary characteristic. The key ingredients in the proof are the following: (a) Proposition 2.1 which shows that after taking the reduced fiber product of f with a generically étale morphism π: Y → X , we may assume that the smooth locus of f intersects every geometric fiber, and (b) Proposition 1.1 which is a purely algebraic analogue of the "moving branch points" argument in Graber-Harris-Starr. The reader is cautioned that our definition of "separably rationally connected" differs slightly from the original definition.
Character expansions and unrefined minimal K-types
Authors: Kim Ju-Lee , Murnaghan Fiona
Published: February 2007

Let k be a p -adic field. Let G be the group of k -rational points of a connected reductive group G defined over k , and let [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /] be its Lie algebra. Under certain hypotheses on G and k , we get a new character expansion, called a Γ- asymptotic expansion , for representations of positive depth [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="02i" /]. This character expansion is valid on the G -domain [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="03i" /], which is bigger than that where the Harish-Chandra-Howe character expansion is known to be valid.
Where Have All The Babies Gone?: Toward an Anthropology of Infants (and Their Caretakers)
Authors: Gottlieb Alma
Published: February 2007

In much anthropological literature infants are frequently neglected as outside the scope of both the concept of culture and disciplinary methods. This article proposes six reasons for this exclusion of infants from anthropological discussse include the fieldworker's own memories and parental status, the problematic question of agency in infants and their presumed dependence on others, their routine attachment to women, their seeming inability to communicate, their inconvenient propensity to leak from a variety of orifices, and their apparently low quotient of rationality. Yet investigation of how infants are conceived of beyond the industrialized West can lead us to envision them far differently from how they are conceived in the West (including by anthropologists). Confronting such comparative data suggests the desirability of considering infants as both relevant and beneficial to the anthropological endeavor.
Storytelling the Future: Israelis, Immigrants and the Imagining of Community
Authors: Golden Deborah
Published: February 2007

This article addresses the links between national identity, temporal order, and the re-socialization of migrants. Anchored in an ethnographic account of encounters between Israeli Jews and recent migrants to Israel from the former Soviet Union, it looks at ways in which temporal re-ordering was rendered crucial to the moral transformation required of the newcomers. These encounters reveal not only the ways in which Israeli oldtimers endeavored to persuade the newcomers to bracket off their present circumstances in favour of a shared, imagined future, but also how the newcomers sought to contest the use of the future for making meaning of the present. Finally, the paper examines how a more general argument about the modern state's control over time, and the challenges currently being posed to such control, is worked out in the Israeli case [Israel, Soviet migrants, Israel, nationalism, time, future].
An Excess Of Truth: Violence, Conspiracy Theorizing and the Algerian Civil War
Authors: Silverstein Paul A.
Published: February 2007

This essay examines the proliferation of practices of conspiracy theorizing among Algerian citizens and expatriates in light of the current civil war that since 1992 has resulted in 100,000 deaths and an ongoing state of emergency disrupting nascent democratic legal and political processes. Seeking to provide transparent accounts of opaque military actions, Algerian conspiracy theorizing adopts a totalizing rhetoric that eschews uncertainty and fetishizes causality and actor intentionality. The article argues that such rhetoric outlines a shared political culture for Algerians across ethnic, linguistic, and ideological divides. While constituting a vernacular sphere of transnational knowledge production and circulation (a Foucauldian "regime of truth"), this political culture of conspiracy simultaneously provides a discursive prop for military and governmental structures of power whose coherence is otherwise placed in jeopardy by the civil war violence. What is at issue in the end is the role of social practices like conspiracy theorizing in dialectical structures of hegemonic processes.
Ramona and Postnationalist American Studies: On 'Our America' and the Mexican Borderlands
Authors: Irwin Robert McKee
Published: February 2007

The recent rediscovery of Helen Hunt Jackson's Ramona (1884) by scholars of US-Mexico border studies has provided interesting insights into intercultural relations in the late nineteenth-century U.S. Southwest. However, Jackson's idealization of race relations in mixed-race Mexico, echoed by none other than Jos� Marti in his 1887 Spanish translation of the novel, reflects what has lately become a commonplace in contemporary border studies: a blindness to Mexico's northern borderlands. In the late nineteenth century, the northern Mexican borderlands were, in fact, the scene of racial conflicts involving local indigenous groups, which were as violent as those on the US side of the border. In the spirit of the "new American studies," this paper argues for an expansion of border studies beyond the context of the Chicano Southwest into the "other borderlands" of northern Mexico, and for a move toward truly bilingual and postnationalist American studies scholarship that positions the United States more meaningfully within the context of the Americas.
Border City: Race and Social Distance in Los Angeles
Authors: Hise Greg
Published: February 2007

Los Angeles and history are not terms that couple easily in the popular imaginary or, for that matter, in the imagination of scholars who study American society and culture. Rather, accounts of this city's past evoke and at times emulate turn-of-the-century booster promotions intended to draw émigrés to a land of prosperity and progress, a place where the future would arrive first; that future focus has held an undue grip on our analysis of greater Los Angeles. If we were to resurrect the pueblo and re-examine the first decades of city building following the American conquest we would discover a border zone, a site and locale where people, resources, and ideas originating across the globe came together and in coming together, Tongva, Spaniards, Mexicans, Californios, Yankees, and others created a hybrid or metis city and culture. Within this border city, Anglos asserted their political, economic, and social capital and in doing so orchestrated and regulated the use and meaning of urban space through agencies and institutions of the local state. Social segregation (by race-ethnicity, income, gender) and functional segregation (zoning activities and assigning these to discrete districts) are signature aspects of American cities and Angelenos used both in a process of place-making and identity formation that defined space in the city. That history matters because all manner of metrics underscore the fact that space matters; where you live, which school district or council district you call home, which hospital an ambulance takes you to, all those lines on the map define the odds you will graduate high school, attend a university, or whether you will survive a heart attack.