bluuebunny/crossref_metadata_2025 huggingface dataset:
Wealth in America
Authors: Keister Lisa A.
Published: February 2010

Wealth ownership in the United States has always concentrated in the hands of a small minority of the population. Because of scarce data on wealth ownership, the nature of wealth ownership distribution and knowledge about wealth inequality has received little attention from social scientists. Keister synthesizes theory and data from various sources to present a picture of househould wealth distribution from 1962 to 1995. Utilizing existing survey data and a unique simulation model, she isolates and examines processes that create this distribution, paying particular attention to the wealth ownership and accumulation of top wealth holders, those who control the bulk of household wealth. She identifies trends in wealth mobility that are not possible to estimate with traditional research methods. The results underscore the importance of wealth as an indicator of well-being, identify important causes of wealth inequality, and propose methods of lessening the recent increase in the concentration of wealth.
Input-Output Analysis
Authors: Miller Ronald E. , Blair Peter D.
Published: February 2010

This edition of Ronald Miller and Peter Blair's classic textbook is an essential reference for students and scholars in the input-output research and applications community. The book has been fully revised and updated to reflect important developments in the field since its original publication. New topics covered include SAMs (and extended input-output models) and their connection to input-output data, structural decomposition analysis (SDA), multiplier decompositions, identifying important coefficients, and international input-output models. A major new feature of this edition is that it is also supported by an accompanying website with solutions to all problems, wide-ranging real-world data sets, and appendices with further information for more advanced readers. Input-Output Analysis is an ideal introduction to the subject for advanced undergraduate and graduate students in a wide variety of fields, including economics, regional science, regional economics, city, regional and urban planning, environmental planning, public policy analysis and public management.
Cost-Benefit Analysis of Environmental Change
Authors: Johansson Per-Olov
Published: February 2010

This book is an advanced text in applied welfare economics and its application to environmental economics. The author goes far beyond the existing literature on the valuation of environmental benefits, deriving sets of cost-benefit rules which can be used to assess private and public sector projects which affect the environment. He explains how valuation studies can be augmented so as to yield the information necessary for decision-making, showing how externalities, taxes, unemployment, risk, irreversibilities, flow and stock pollutants, discounting, and intergenerational distribution should be treated in social cost-benefit analysis. Drawing on a number of empirical illustrations, this book will be of interest not only to those taking advanced courses in environmental economics, welfare economics, and public economics, but also as a reference for those undertaking project evaluations in government and business.
Time Series and Dynamic Models
Authors: Gourieroux Christian , Monfort Alain
Published: February 2010

In this book Christian Gourieroux and Alain Monfort provide an up-to-date and comprehensive analysis of modern time series econometrics. They have succeeded in synthesising in an organised and integrated way a broad and diverse literature. While the book does not assume a deep knowledge of economics, one of its most attractive features is the close attention it pays to economic models and phenomena throughout. The coverage represents a major reference tool for graduate students, researchers and applied economists. The book is divided into four sections. Section one gives a detailed treatment of classical seasonal adjustment or smoothing methods. Section two provides a thorough coverage of various mathematical tools. Section three is the heart of the book, and is devoted to a range of important topics including causality, exogeneity shocks, multipliers, cointegration and fractionally integrated models. The final section describes the main contribution of filtering and smoothing theory to time series econometric problems.
Medieval English Conveyances
Authors: Kaye J. M.
Published: February 2010

This study of the documents used in medieval England for the creation and transfer of interests in real property is the first book devoted exclusively to the subject since the publication of Thomas Madox's Formulare Anglicanum in 1702. The transactions covered include grants in fee and in perpetual alms, leases for life and for years, exchanges, surrenders and releases. Analysis of each kind of transaction is partly by way of commentary on the formulae of deeds, selected from the many thousands found in published cartularies and collections, and partly by relating the deeds to the relevant law of their periods, as found in early treatises, decided cases and the Year Books. The aim is to enable readers to identify and categorise deeds accurately, to appreciate their legal effects and to note instances where the practice of conveyancers and their clients differed from what is supposed to have been the law.
Semi-Citizenship in Democratic Politics
Authors: Cohen Elizabeth F.
Published: February 2010

In every democratic polity there exist individuals and groups who hold some but not all of the essential elements of citizenship. Scholars who study citizenship routinely grasp for shared concepts and language that identify forms of membership held by migrants, children, the disabled, and other groups of individuals who, for various reasons, are neither full citizens nor non-citizens. This book introduces the concept of semi-citizenship as a means to dramatically advance debates about individuals who hold some but not all elements of full democratic citizenship. By analytically classifying the rights of citizenship and their various combinations, scholars can typologize semi-citizens and produce comparisons of different kinds of semi-citizenships and of semi-citizenships in different states. The book uses theoretical analysis, historical examples, and contemporary cases of semi-citizenship to illustrate how normative and governmental doctrines of citizenship converge and conflict, making semi-citizenship an enduring and inevitable part of democratic politics.
Dynamic General Equilibrium andT-Period Fund Separation
Authors: Gerber Anke , Hens Thorsten , Woehrmann Peter
Published: February 2010

In a dynamic general equilibrium model, we derive conditions for a mutual fund separation property by which the savings decision is separated from the asset allocation decision. With logarithmic utility functions, this separation holds for any heterogeneity in discount factors, while the generalization to constant relative risk aversion holds only for homogeneous discount factors but allows for any heterogeneity in endowments. The logarithmic case provides a general equilibrium foundation for the growth-optimal portfolio literature. Both cases yield equilibrium asset pricing formulas that allow for investor heterogeneity, in which the return process is endogenous and asset prices are determined by expected discounted relative dividends. Our results have simple asset pricing implications for the time series as well as the cross section of relative asset prices. It is found that on data from the Dow Jones Industrial Average, a risk aversion smaller than in the logarithmic case fits best.
The work of conservation organisations in sub-Saharan Africa
Authors: Brockington Dan , Scholfield Katherine
Published: February 2010

Conservation non-governmental organisations (NGOs) have excited a great deal of comment and debate, generally quite divided, in diverse journals. Some advocate them as forces for good, others decry their clumsy dealings with rural peoples and the impoverishment their activities can cause. The debate suffers in two ways. First, it ignores a large parallel literature about the work of development NGOs. Second, there is a paucity of general knowledge about the state of the conservation NGO sector. We do not know where it works, what the main players are doing, or much at all about the extent or activities of the smaller conservation organisations. We do not know how much money the sector spends. In this paper we first briefly outline why work on development NGOs should be applied to conservation NGOs, and then offer an overview of the sector's activities based on a survey of over 280 organisations. We describe some of the basic contours of these activities, and reflect on the implications of our findings for existing writings about conservation NGOs and future research.
Hidden in Plain View: Brajbhasha Poets at the Mughal Court
Authors: BUSCH ALLISON
Published: February 2010

Brajbhasha literature is a domain of Mughal culture seldom investigated by scholars, to the detriment of our understanding of both. While the Mughal court is famed for its lavish support of Persian writers, a surprising number of Brajbhasha poets also attracted the notice of Mughal patrons. In this paper I look at the lives and texts of important Braj writers who worked in Mughal settings, with a view to uncovering the nature of the social, political and cultural interactions that this kind of patronage represents. Why these poets have been largely lost to social and literary history is another concern, along with the challenges of trying to recover their stories.
International Law Scholarship in Post-colonial India: Coping with Dualism
Authors: CHIMNI B. S.
Published: February 2010

This essay seeks to sketch and evaluate international law scholarship in post-colonial India in the period 1947–2007. The exercise is undertaken to assess how Indian scholarship has coped with the dual life of international law: the fact that it is both an instrument of domination and possible emancipation. It is contended that while the dominant approach of formalist dualism, which critiques colonial international law but embraces the narrative of progress in the present, has made a seminal contribution to the world of international law, in particular the first articulation of Third World approaches to international law (TWAIL), it has not adequately addressed deep systemic structures that underlie contemporary international law. It is argued that this task is performed more effectively by a critical dualist approach that problematizes the structure, ideology, and practices of global capitalism. The essay concludes by reflecting on the future tasks of Indian scholarship.
Self-Defence in Response to Attacks by Non-state Actors in the Light of Recent State Practice: A Step Forward?
Authors: VAN STEENBERGHE RAPHAËL
Published: February 2010

This article analyses the recent state practice in which the right of self-defence has been invoked in order to justify the use of force in response to attacks by non-state actors. The main purpose of this analysis is to determine whether the law of self-defence has evolved through this practice. It is submitted that the latter confirms the tendency, evidenced by the US operation ‘Enduring Freedom’ in Afghanistan in 2001, towards allowing states to respond in self-defence to private armed attacks, that is, attacks which are committed by non-state actors only. The article also aims to shed some light on other fundamental conditions of the law of self-defence which played a significant role in the legal assessment of the recent state practice. It is argued in this respect that this practice confirms that any armed attack must reach some level of gravity – which may be assessed by accumulating minor uses of force – in order to trigger the right of self-defence, and that proportionality of the action taken in self-defence may be assessed in quantitative terms, but only as a means of making a prima facie judgement about the necessity of this action.
Assessing the potential of multispectral remote sensing for lithological mapping on the Antarctic Peninsula: case study from eastern Adelaide Island, Graham Land
Authors: Haselwimmer C.E. , Riley T.R. , Liu J.G.
Published: February 2010

The results of lithological mapping using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data for the Wright Peninsula region of Adelaide Island, Antarctic Peninsula are compared with existing geological maps and recent field observations to assess the potential of multispectral remote sensing to undertake lithological mapping on the Antarctic Peninsula. The Wright Peninsula comprises calc-alkaline intrusive rocks ranging from granite to gabbro, volcanic rocks of acidic to intermediate composition, and arc-related sediments. The reflective and thermal bands of a single ASTER image were analysed with reference to reflectance spectra of rock samples from the study area. Assessment of the ASTER mapping outcomes was undertaken with a newly compiled geological map of Adelaide Island and observations made during recent fieldwork. The results demonstrate that ASTER can uniquely discriminate granitoid intrusive rocks and altered rhyolitic volcanic rocks that display distinctive spectral properties. The results are more ambiguous at discriminating more intermediate/mafic rocks such as diorite/gabbro, andesite/basalt and chlorite-bearing sediments due to the similarity in spectral properties. These results demonstrate that although ASTER data are limited in their ability to uniquely discriminate lithologies they can provide important lithological information in support of geological mapping on the Antarctic Peninsula.
Well-Being Curves Across Transitions
Authors: Perren Sonja , Keller Roger , Passardi Marco , Scholz Urte
Published: February 2010

A newly developed instrument (retrospective well-being curves: WBC) was applied in two studies. In Study 1, a sample of 145 adults (M = 26.6 years) completed the WBC twice for different normative transitions. In Study 2, 151 university freshmen (M = 21.5 years) reported on their subjective well-being at 9 consecutive measurement points during their transition to university and completed the WBC at T10. In both studies, personality factors were assessed. Retest reliability of the individual growth parameters (intercept, linear, and quadratic change) was moderate to high (Study 1), whereas convergent validity of the growth parameters was moderate (Study 2). The results demonstrated distinct well-being trajectories for different transitions. Situational factors (e.g., timing) and personality factors (neuroticism and extraversion) were significantly associated with well-being. The results indicate that, although the use of the WBC may be limited by its retrospective design, the instrument provides a time-efficient way of measuring hedonic adaptation processes.
Karpaltunnelsyndrom – moderne Diagnostik und Management
Authors: Gautschi  , Land  , Hoederath  , Fournier  , Hildebrandt  , Cadosch
Published: February 2010

Das Karpaltunnelsyndrom ist das häufigste Kompressionssyndrom der Armnerven (ca. 3% der erwachsenen Bevölkerung sind davon betroffen) und ist durch Schmerzen und Kribbelparästhesien im Versorgungsgebiet des Nervus medianus charakterisiert. Eine Thenarmuskelatrophie mit entsprechender Muskelschwäche ist eine späte Manifestation der Krankheit. Zur Bestätigung der Verdachtsdiagnose stehen elektrophysiologische Tests zur Verfügung. Eine Bildgebung mittels Magnetresonanztomographie kann für die Diagnose atypischer Fälle verwendet werden. Ergotherapeutische Massnahmen, orale Steroide und Steroidinjektionen führen in milden Fällen zu einer Symptomlinderung. Die chirurgische Entlastung des Karpaltunnels gilt als die klassische Behandlung schwerer Fälle sowie solcher, welche nicht auf konservative Behandlungsoptionen ansprechen, und zeigt exzellente Resultate. Im Folgenden werden die klinische Präsentation, die Diagnostik und die massgebenden Therapieoptionen des Karpaltunnelsyndroms praxisnah besprochen.
Mechanics of the giant radiating Mackenzie dyke swarm: A paleostress field modeling
Authors: Hou Guiting , Kusky T. M. , Wang Chuancheng , Wang Yanxin
Published: February 2010

The 1.27 Ga Mackenzie dyke swarm of the Canadian Shield is a giant radiating dyke swarm that gradually swings in orientation from N‐S in the focal area to NW‐SE trends in peripheral areas. In this paper, we propose a new model (the “Plug” model) that accounts for the paleostress contribution to the mechanism of emplacement for the Mackenzie dyke swarm in the Canadian Shield. The 1.27 Ga stress field on the Canadian Shield calculated by the “Plug” model explains the radiating nature of the Mackenzie dyke swarm around the Coppermine River lava field by local stress concentrations. The parallel nature of the dyke swarm at distance (more than 1000 km) from the focal source can be explained by the existence of a regional tectonic stress field created by ridge push acting on the southeast margin of the Canadian Shield from the Grenville Ocean. The thin elastic plate and two‐dimensional cross‐section modeling suggest that the interaction between stresses from a mantle upwelling and the Grenville Ocean spreading play an important role in the intrusion mechanism of the Mackenzie dyke swarm. The change in dyke orientation from N‐S trending to NW‐SE trending is caused by coupling between resistance from the focal area (Plug area) and a Grenville Ocean ridge push.
Comparison between observations and models of the Mozambique Channel transport: Seasonal cycle and eddy frequencies
Authors: van der Werf P. M. , van Leeuwen P. J. , Ridderinkhof H. , de Ruijter W. P. M.
Published: February 2010

A time series of the observed transport through an array of moorings across the Mozambique Channel is compared with that of six model runs with ocean general circulation models. In the observations, the seasonal cycle cannot be distinguished from red noise, while this cycle is dominant in the transport of the numerical models. It is found, however, that the seasonal cycles of the observations and numerical models are similar in strength and phase. These cycles have an amplitude of 5 Sv and a maximum in September, and can be explained by the yearly variation of the wind forcing. The seasonal cycle in the models is dominant because the spectral density at other frequencies is underrepresented. Main deviations from the observations are found at depths shallower than 1500 m and in the 5/y–6/y frequency range. Nevertheless, the structure of eddies in the models is close to the observed eddy structure. The discrepancy is found to be related to the formation mechanism and the formation position of the eddies. In the observations, eddies are frequently formed from an overshooting current near the mooring section, as proposed by Ridderinkhof and de Ruijter (2003) and Harlander et al. (2009). This causes an alternation of events at the mooring section, varying between a strong southward current, and the formation and passing of an eddy. This results in a large variation of transport in the frequency range of 5/y–6/y. In the models, the eddies are formed further north and propagate through the section. No alternation similar to the observations is observed, resulting in a more constant transport.
Online simulations of mineral dust aerosol distributions: Comparisons to NAMMA observations and sensitivity to dust emission parameterization
Authors: Nowottnick E. , Colarco P. , Ferrare R. , Chen G. , Ismail S. , Anderson B. , Browell E.
Published: February 2010

A key uncertainty within Earth system modeling lies in the parameterization of the emission process for mineral aerosols, where emission scheme choice can have implications for emitted dust fluxes. For our study, we include versions of dust emission schemes from the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) and Dust Entrainment and Deposition (DEAD) models in the new NASA Goddard Earth Observing System version 4 model, to identify differences in simulated dust distributions caused by varying the emission scheme. The GOCART and DEAD schemes differ in their parameterization of the mobilization process, including their sensitivity to meteorological variables and the determination of the emitted particle size distribution. We focus on Saharan dust events during the NASA African Monsoon Multidisciplinary Analyses field campaign (August–September 2006) to compare with in situ, ground‐based, and remote sensing observations. We find that the emission schemes produce comparable aerosol optical thickness and vertical extinction profiles, and their distributions compare well with observations from the space‐based MODIS, OMI, MISR, and CALIPSO sensors, and the airborne LASE lidar. Neither emission scheme does especially well at capturing the variability or magnitude of specific dust events over the source region when compared to AERONET and MISR observations, but both improve downwind of the dust sources. Despite the similarities in the optical comparisons, the schemes differ in mass loadings owing to differences in their emitted dust particle size distributions over the source region. Our findings suggest that emission scheme choice for general circulation models is important only over the source region, where the emitted particle size distributions and corresponding mass budgets of emissions are influenced.
Saltier, Hotter, More Acidic, and Less Diverse? Observing the Future Ocean: OceanObs'09: Ocean Information for Society—Sustaining the Benefits, Realizing the Potential; Venice, Italy, 21–25 September 2009
Authors: Harrison D. E. , Legler David M.
Published: February 2010

Ten years ago, a vision of a sustained system for providing information about the global ocean was presented at OceanObs'99, the first International Conference on the Ocean Observing System for Climate. An initial ocean‐observing system for marine physical climate and carbon is being implemented as a result. Many other observing activities focused on marine biological and geochemical systems also have been undertaken in the past decade. These activities collectively have proven to be fundamental to the Intergovernmental Panel on Climate Change's assessments, have documented profound marine variability and change, have better characterized stresses on global living marine systems, and have supported a range of forecasts and projections of the coming decades.
Jorge L. Sarmiento Receives 2009 Roger Revelle Medal
Authors: Gruber Nicolas , Sarmiento Jorge L.
Published: February 2010

Jorge L. Sarmiento was awarded the 2009 Roger Revelle Medal at the AGU Fall Meeting Honors Ceremony, held on 16 December 2009 in San Francisco, Calif. The medal is for “outstanding contributions in atmospheric sciences, atmosphere‐ocean coupling, atmosphere land coupling, biogeochemical cycles, climate, or related aspects of the Earth system.”
Changes of protein solutions during storage: a study of albumin pharmaceutical preparations
Authors: Christiansen Cathrine , Skotland Tore
Published: February 2010

During the production of air‐filled albumin microspheres, to be used as an ultrasound contrast agent, it was observed that some albumin lots could not be used owing to albumin precipitation. In order to understand the reason for these lot‐to‐lot variations, 24 lots of 5% (w/v) human albumin pharmaceutical preparations were analysed. The results revealed that the good albumin lots all contained <0.03 mol of free SH groups per mol of albumin. The precipitation observed with other lots was most probably due to higher amounts of free SH groups. The lower amount of free SH groups in the good lots correlated with: (i) a yellow colour of the solutions and a UV–visible spectrum similar to that observed for non‐enzymatic glycosylation; (ii) a decreased fructosamine content; (iii) an increased mobility against the anode in isoelectric focusing; and (iv) an increased truncation of the two N‐terminal amino acids. No, or only small, differences were observed for the amounts of albumin dimer, albumin aggregates and protein impurities, and these could not account for the albumin precipitation. The differences observed between the albumin lots were most probably due to varying storage times and/or storage conditions, and incubation experiments revealed changes in all parameters that differed between the good and bad lots. Increasing the storage temperature or exposing the solutions to light resulted in a faster decrease of free SH groups and increase of the yellow colouration. It is likely that at least some of the changes observed were due to reactive degradation products formed from the stabilizer N‐acetyl‐L‐tryptophan. The results presented should also be of interest regarding the storage of monoclonal antibodies and other proteins used in pharmaceuticals.
Denatured proteins facilitate the formation of the football-shaped GroEL–(GroES)2 complex
Authors: Sameshima Tomoya , Iizuka Ryo , Ueno Taro , Funatsu Takashi
Published: February 2010

Controversy exists over whether the chaperonin GroEL forms a GroEL–(GroES)2 complex (football-shaped complex) during its reaction cycle. We have revealed previously the existence of the football-shaped complex in the chaperonin reaction cycle using a FRET (fluorescence resonance energy transfer) assay [Sameshima, Ueno, Iizuka, Ishii, Terada, Okabe and Funatsu (2008) J. Biol. Chem. 283, 23765–23773]. Although denatured proteins alter the ATPase activity of GroEL and the dynamics of the GroEL–GroES interaction, the effect of denatured proteins on the formation of the football-shaped complex has not been characterized. In the present study, a FRET assay was used to demonstrate that denatured proteins facilitate the formation of the football-shaped complex. The presence of denatured proteins was also found to increase the rate of association of GroES to the trans-ring of GroEL. Furthermore, denatured proteins decrease the inhibitory influence of ADP on ATP-induced association of GroES to the trans-ring of GroEL. From these findings we conclude that denatured proteins facilitate the dissociation of ADP from the trans-ring of GroEL and the concomitant association of ATP and the second GroES.
Inhibition of apoptotic signalling in spermine‐treated vascular smooth muscle cells by a novel glutathione precursor
Authors: Sinha‐Hikim Indrani , Shen Ruoqing , Kovacheva Ekaterina , Crum Albert , Vaziri Nosratola D. , Norris Keith C.
Published: February 2010

CKD (chronic kidney disease) is a public health problem, mediated by haemodynamic and non‐haemodynamic events including oxidative stress. We investigated the effect of two GSH (glutathione) precursors, NAC (N‐acetylcysteine) and cystine as the physiological carrier of cysteine in GSH with added selenomethionine (F1) in preventing spermine (uraemic toxin)‐induced apoptosis in cultured human aortic VSMC (vascular smooth muscle cells). VSMCs exposed to spermine (15 μM) with or without antioxidants (doses 50, 100, 200 and 500 μg/ml) were assessed for apoptosis, JNK (c‐Jun‐NH2‐terminal kinase) activation and iNOS (inducible nitric oxide synthase) induction and activation of intrinsic pathway signalling. Spermine exposure resulted in activation of JNK and iNOS induction and apoptosis. NAC and F1 (dose range 50–500 μg/ml) attenuated spermine‐induced acceleration of VSMC apoptosis but only F1 (at 200 and 500 μg/ml) maintained spermine‐induced apoptosis at control levels. Spermine‐induced JNK activation was prevented by 200 μg/ml of both NAC and F1, while iNOS induction was blocked only by F1. Notably, the adverse effects of spermine on BAX/BCL‐2 ratio, cytochrome c release and caspase activation was fully attenuated by F1. In conclusion, F1 was more effective than NAC in preventing spermine‐induced apoptosis and downstream changes in related signal transduction pathways in VSMCs. Further studies are needed to examine the effect of these compounds in preventing CKD‐associated vascular disease.
Flat bases of invariant polynomials and P̂-matrices of E7 and E8
Authors: Talamini Vittorino
Published: February 2010

Let G be a compact group of linear transformations of a Euclidean space V. The G-invariant C∞ functions can be expressed as C∞ functions of a finite basic set of G-invariant homogeneous polynomials, sometimes called an integrity basis. The mathematical description of the orbit space V/G depends on the integrity basis too: it is realized through polynomial equations and inequalities expressing rank and positive semidefiniteness conditions of the P̂-matrix, a real symmetric matrix determined by the integrity basis. The choice of the basic set of G-invariant homogeneous polynomials forming an integrity basis is not unique, so it is not unique the mathematical description of the orbit space too. If G is an irreducible finite reflection group, Saito et al. [Commun. Algebra 8, 373 (1980)] characterized some special basic sets of G-invariant homogeneous polynomials that they called flat. They also found explicitly the flat basic sets of invariant homogeneous polynomials of all the irreducible finite reflection groups except of the two largest groups E7 and E8. In this paper the flat basic sets of invariant homogeneous polynomials of E7 and E8 and the corresponding P̂-matrices are determined explicitly. Using the results here reported one is able to determine easily the P̂-matrices corresponding to any other integrity basis of E7 or E8. From the P̂-matrices one may then write down the equations and inequalities defining the orbit spaces of E7 and E8 relatively to a flat basis or to any other integrity basis. The results here obtained may be employed concretely to study analytically the symmetry breaking in all theories where the symmetry group is one of the finite reflection groups E7 and E8 or one of the Lie groups E7 and E8 in their adjoint representations.
First operation of the charge-breeder electron-cyclotron-resonance ion source at the Texas A&M Cyclotron Institute
Authors: May D. P. , Tabacaru G. , Abegglen F. P. , Cornelius W. D.
Published: February 2010

The 14.5 GHz electron-cyclotron-resonance ion source (ECRIS) designed and fabricated specifically for charge breeding has been installed at the Texas A&M University Cyclotron Institute for use in the institute's ongoing radioactive-ion-beam upgrade. The initial testing of the source has just begun with magnetic analysis of the ECRIS beam. The source has only been conditioning for a brief time at low microwave power, and it is continuing to improve. After the source has been conditioned and characterized, charge-breeding trials with stable beams from a singly ionizing source will begin.
Modeling the solid-liquid phase transition in saturated triglycerides
Authors: Pink David A. , Hanna Charles B. , Sandt Christophe , MacDonald Adam J. , MacEachern Ronald , Corkery Robert , Rousseau Dérick
Published: February 2010

We investigated theoretically two competing published scenarios for the melting transition of the triglyceride trilaurin (TL): those of (1) Corkery et al. [Langmuir 23, 7241 (2007)], in which the average state of each TL molecule in the liquid phase is a discotic “Y” conformer whose three chains are dynamically twisted, with an average angle of ∼120° between them, and those of (2) Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid-state conformation of the TL molecule in the liquid phase is a nematic h∗-conformer whose three chains are in a modified “chair” conformation. We developed two competing models for the two scenarios, in which TL molecules are in a nematic compact-chair (or “h”) conformation, with extended, possibly all-trans, chains at low-temperatures, and in either a Y conformation or an h∗ conformation in the liquid state at temperatures higher than the phase-transition temperature, T∗=319 K. We defined an h-Y model as a realization of the proposal of Corkery et al. [Langmuir 23, 7241 (2007)], and explored its predictions by mapping it onto an Ising model in a temperature-dependent field, performing a mean-field approximation, and calculating the transition enthalpy ΔH. We found that the most plausible realization of the h-Y model, as applied to the solid-liquid phase transition in TL, and likely to all saturated triglycerides, gave a value of ΔH in reasonable agreement with the experiment. We then defined an alternative h-h∗ model as a realization of the proposal of Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid phase exhibits an average symmetry breaking similar to an h conformation, but with twisted chains, to see whether it could describe the TL phase transition. The h-h∗ model gave a value of ΔH that was too small by a factor of ∼3–4. We also predicted the temperature dependence of the 1132 cm−1 Raman band for both models, and performed measurements of the ratios of three TL Raman bands in the temperature range of −20 °C≤T≤90 °C. The experimental results were in accord with the predictions of the h-Y model and support the proposal of Corkery et al. [Langmuir 23, 7241 (2007)] that the liquid state is made up of molecules that are each, on average, in a Y conformation. Finally, we carried out computer simulations of minimal-model TLs in the liquid phase, and concluded that although the individual TL molecules are, on average, Y conformers, long-range discotic order is unlikely to exist.
Boundary stabilization of transmission problems
Authors: Cardoso Fernando , Vodev Georgi
Published: February 2010

We study the transmission problem in bounded domains with dissipative boundary conditions. Under some natural assumptions, we prove uniform bounds of the corresponding resolvents on the real axis at high frequency and, as a consequence, we obtain regions free of eigenvalue. To this end, we extend the result of Cardoso et al. [“Distribution of resonances and local energy decay in the transmission problem. II,” Math. Res. Lett. 6, 377 (1999)] under more general assumptions. As an application, we get exponential decay of the energy of the solutions of the corresponding mixed boundary value problems.
Whistler wave excitation and effects of self-focusing on ion beam propagation through a background plasma along a solenoidal magnetic field
Authors: Dorf Mikhail A. , Kaganovich Igor D. , Startsev Edward A. , Davidson Ronald C.
Published: February 2010

This paper extends studies of ion beam transport through a background plasma along a solenoidal magnetic field by Kaganovich et al. [Phys. Plasmas 15, 103108 (2008)] to the important regime of moderate magnetic field strength satisfying ωce>2βbωpe. Here, ωce and ωpe are the electron cyclotron frequency and electron plasma frequency, respectively, and βb=vb/c is the directed ion beam velocity normalized to the speed of light. The electromagnetic field perturbations excited by the ion beam pulse in this regime are calculated analytically and verified by comparison with the numerical simulations. The degrees of beam charge neutralization and current neutralization are estimated, and the transverse component of the Lorentz force associated with the excited electromagnetic field is calculated. It is found that the plasma response to the ion beam pulse is significantly different depending on whether the value of the solenoidal magnetic field is below or above the threshold value specified by ωcecr=2βbωpe, and corresponding to the resonant excitation of large-amplitude whistler waves. The use of intense whistler wave excitations for diagnostic purposes is also discussed.
Reformulating the Schrödinger equation as a Shabat–Zakharov system
Authors: Boonserm Petarpa , Visser Matt
Published: February 2010

We reformulate the second-order Schrödinger equation as a set of two coupled first-order differential equations, a so-called “Shabat–Zakharov system” (sometimes called a “Zakharov–Shabat” system). There is considerable flexibility in this approach, and we emphasize the utility of introducing an “auxiliary condition” or “gauge condition” that is used to cut down the degrees of freedom. Using this formalism, we derive the explicit (but formal) general solution to the Schrödinger equation. The general solution depends on three arbitrarily chosen functions, and a path-ordered exponential matrix. If one considers path ordering to be an “elementary” process, then this represents complete quadrature, albeit formal, of the second-order linear ordinary differential equation.
On eigenmodes, stiffness, and sensitivity of atomic force microscope cantilevers in air versus liquids
Authors: Kiracofe Daniel , Raman Arvind
Published: February 2010

The effect of hydrodynamic loading on the eigenmode shapes, modal stiffnesses, and optical lever sensitivities of atomic force microscope (AFM) microcantilevers is investigated by measuring the vibrations of such microcantilevers in air and water using a scanning laser Doppler vibrometer. It is found that for rectangular tipless microcantilevers, the measured fundamental and higher eigenmodes and their equivalent stiffnesses are nearly identical in air and in water. However, for microcantilevers with a tip mass or for picket shaped cantilevers, there is a marked difference in the second (and higher) eigenmode shapes between air and water that leads to a large decrease in their modal stiffness in water as compared to air as well as a decrease in their optical lever sensitivity. These results are explained in terms of hydrodynamic interactions of microcantilevers with nonuniform mass distribution. The results clearly demonstrate that tip mass and hydrodynamic loading must be taken into account in stiffness calibration and optical lever sensitivity calibration while using higher-order eigenmodes in dynamic AFM.
Quantum Zeno effect and dynamics
Authors: Facchi Paolo , Ligabò Marilena
Published: February 2010

If frequent measurements ascertain whether a quantum system is still in a given subspace, it remains in that subspace and a quantum Zeno effect takes place. The limiting time evolution within the projected subspace is called quantum Zeno dynamics. This phenomenon is related to the limit of a product formula obtained by intertwining the time evolution group with an orthogonal projection. By introducing a novel product formula, we will give a characterization of the quantum Zeno effect for finite-rank projections in terms of a spectral decay property of the Hamiltonian in the range of the projections. Moreover, we will also characterize its limiting quantum Zeno dynamics and exhibit its (not necessarily bounded from below) generator as a generalized mean value Hamiltonian.
Theory of hot-carrier-induced phenomena in GaN high-electron-mobility transistors
Authors: Puzyrev Y. S. , Tuttle B. R. , Schrimpf R. D. , Fleetwood D. M. , Pantelides S. T.
Published: February 2010

It has long been known that GaN high-electron-mobility transistors can degrade significantly under hot electron stress. More recently, an increase in the yellow luminescence was observed under similar stress conditions. The two phenomena have been attributed to defects but no specific physical mechanism has been proposed. Here we report first-principles density-functional calculations of hydrogenated Ga vacancies and show that hydrogen release by hot electrons provides an explanation for both phenomena.
Global weak solution for a equations in plasma
Authors: Guo Boling , Huang Daiwen
Published: February 2010

The existence of global weak solutions of the initial boundary value problem to a simplified equations, derived from the equations of two fluid system in plasma, is proven by using energy method and some embedding theorems in Sobolev–Orlicz space.
A study of resistive switching effects on a thin FeOx transition layer produced at the oxide/iron interface of TiN/SiO2/Fe-contented electrode structures
Authors: Feng Li-Wei , Chang Chun-Yen , Chang Yao-Feng , Chen Wei-Ren , Wang Shin-Yuan , Chiang Pei-Wei , Chang Ting-Chang
Published: February 2010

Large (>102) and stable resistance switching characteristics were demonstrated in TiN/SiO2/Fe structure due to the presence of a thin FeOx transition layer at the SiO2/Fe interface, produced spontaneously during the plasma-enhanced tetraethyl orthosilicate oxide deposition process. Addition of Pt into Fe electrode, i.e., a TiN/SiO2/Fe0.73Pt0.27 structure, was observed to improve the data dispersion of switching parameters, associating with the decrease in Fe content inside the FeOx layer. Additionally, current-voltage fitting data shows that current transport mechanism is governed by Ohm’s law in low voltage region and Pool–Frenkel behavior in high voltage region, consisting with FeOx phase transition characteristics.
Process temperature dependent high frequency capacitance-voltage response of ZrO2/GeO2/germanium capacitors
Authors: Bethge O. , Abermann S. , Henkel C. , Straif C. J. , Hutter H. , Smoliner J. , Bertagnolli E.
Published: February 2010

ZrO 2 / GeO 2 dielectrics are grown on germanium substrates by Atomic Layer Deposition (ALD) at substrate temperatures of 150, 200, and 250 °C, respectively. The impact of the deposition temperature on the electrical and structural properties of MOS capacitors is investigated. A significant influence of the ALD temperature on the high frequency capacitance in inversion can be observed, resulting in a shift of the minority carrier response time from 1.15 to 0.2 μs. Time-of-flight secondary ion mass spectroscopy investigations indicate a distinctive depletion of interfacial GeO at higher ALD temperatures, which give rise to trap levels near the oxide/Ge interface.
Ultrafast saturable absorption devices incorporating efficiently electrosprayed carbon nanotubes
Authors: Chu Suho , Han Won-Suk , Kim Il-Doo , Han Young-Geun , Lee Kwanil , Lee Sang Bae , Song Yong-Won
Published: February 2010

We demonstrate saturable absorption operation of single-walled carbon nanotubes (CNTs) deposited by an efficient electrospray process that provides target-localized deposition with a homogeneous dispersion of the nanomaterials. An improvement in deposition efficiency of 95% is achieved. CNT dispersion/deposition conditions are optimized for suppressed CNT agglomeration, thereby maximizing the nonlinear absorption of CNTs. An ultrafast saturable absorber is formed with side-polished fiber as a substrate for evanescent field interaction of propagated light with CNTs. A resultant fiber mode-locked laser is realized. The laser has output with an estimated pulse duration and repetition rate of 190.9 fs and 3.95 MHz, respectively.
Magnetic noise in MgO-based magnetic tunnel junction rings
Authors: Feng J. F. , Diao Z. , Feng Gen , Nowak E. R. , Coey J. M. D.
Published: February 2010

Magnetization switching is investigated in ring-shaped MgO-based magnetic tunnel junctions with 168% tunneling magnetoresistance. Besides the forward and reverse onion states, two vortex states and several metastable states are observed for the ferromagnetic free layer. Electrical noise is used to characterize the low frequency magnetization dynamics; a stationary 1/f noise spectrum is observed within each magnetic state but they are separated by noise peaks which show a 1/f2 spectrum that is associated with slow random telegraph fluctuations. In the 1/f region, the normalized magnetic noise parameter, αmag, is shown to be consistent with the fluctuation-dissipation theorem.
Effects of illumination on the excess carrier dynamics and variations of the surface states in an AlGaN/GaN heterostructure
Authors: Chang Yun-Chorng
Published: February 2010

Light illumination was observed to be able to change the charge status of surface states in an AlGaN/GaN heterostructure and vary the conductivity of the two-dimensional electron gas channel. The effects of several parameters, including sample temperature, intensity of the ultraviolet (UV) light, wavelength, and intensity of the laser light, were investigated and mathematically analyzed. A physical model that described the dynamics of excess carriers to different light illumination was proposed. Excess carriers created by UV light are able to reach the surface states after overcoming the valence and conduction band discontinuities by absorbing thermal energy and energy of the subsequently incident photon, respectively. Understanding the effect of the ambient illumination can help to achieve a higher sensitivity for an AlGaN/GaN sensor and discover new applications in the future.
Femtosecond carrier dynamics in native and high resistivity iron-doped GaxIn1−xAs
Authors: Sengupta Suranjana , Wilke Ingrid , Dutta Partha. S.
Published: February 2010

We report femtosecond transient reflectivity measurements of as-grown and iron-doped GaxIn1−xAs. A hybrid vertical Bridgman and gradient freezing directional solidification process was employed for the growth of high quality Ga0.69In0.31As:Fe crystals with the uniform impurity doping concentration necessary for high resistivity (1.6×107 Ω cm) and high mobility [(2–3)×103 cm2/V s] material. Carrier lifetimes range from ∼62 fs for as-grown Ga0.09In0.91As to ∼306 fs for Ga0.69In0.31As:Fe. The high carrier mobility along with high resistivity and subpicosecond carrier lifetimes make Ga0.69In0.31As:Fe an excellent candidate for photoconducting antenna based terahertz emitters.
Plasmonic noise in silicon nanolayers
Authors: Pousset J. , Millithaler J.-F. , Reggiani L. , Ziadé P. , Sabatini G. , Palermo C. , Varani L. , Bournel A. , Dollfus P.
Published: February 2010

We report a microscopic investigation of the spectrum of voltage fluctuations in nanometric n-Si layers. Theory makes use of a Monte Carlo simulator self-consistently coupled with a two-dimensional Poisson solver. We consider layers of variable thickness W in the range of 2–100 nm and variable length L in the range of 10–1000 nm embedded in an external dielectric medium. Calculations are performed at T=300 K for different doping levels and in the presence of an applied voltage of increasing strength. The spectra are found to exhibit peaks centered on the terahertz region. For W≥100 nm and carrier densities of 5×1017 and 5×1018 cm−3, the frequency peaks agree with the value of the three dimensional plasma frequency. For W≤100 nm, the results exhibit a plasma frequency that depends on L, thus implying that the oscillation mode is dispersive. The corresponding frequency covers a wide range of values of 0.2–10 THz and is in agreement with the values of the two-dimensional plasma frequency predicted by existing analytical models. At sufficiently high voltages, the two-dimensional plasma peak is washed out and we observe the onset of a peak in the subterahertz region which is associated with transit time instabilities induced by current saturation conditions.
Exactly solvable nonseparable and nondiagonalizable two-dimensional model with quadratic complex interaction
Authors: Cannata F. , Ioffe M. V. , Nishnianidze D. N.
Published: February 2010

We study a quantum model with nonisotropic two-dimensional oscillator potential but with additional quadratic interaction x1x2 with imaginary coupling constant. It is shown that for a specific connection between coupling constant and oscillator frequencies, the model is not amenable to a conventional separation of variables. The property of shape invariance allows to find analytically all eigenfunctions and the spectrum is found to be equidistant. It is shown that the Hamiltonian is nondiagonalizable, and the resolution of the identity must include also the corresponding associated functions. These functions are constructed explicitly, and their properties are investigated. The problem of R-separation of variables in two-dimensional systems is discussed.