bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of U.S. Assistance Programs on the Political and Economic Integration of Western Europe
Authors: Stone Donald C.
Published: May 2006

World War II left Europe economically bankrupt, politically paralyzed, and spiritually sick. In contrast, we find today—thanks to the leaven of the Marshall Plan and other U. S. assistance, and the self-help and mutual-help measures of Western European countries—a vastly improved Continent of Europe.

First, economic collapse has been avoided. The mills, plants, and shops in most countries are humming as they never did before. The current output of industry in Western Europe is roughly forty per cent larger than in 1938, and sixty per cent above that of 1947. Agriculture has likewise shown encouraging improvement. The volume of intra-European trade which had come to a virtual standstill in 1947 has sharply increased until it is now over one-third higher than that of the pre-war era. The dollar deficit in Europe has been substantially reduced from a peak of $7 billion and, except for the special requirements of the post-Korean rearmament program, it would probably have been brought into manageable proportions by 1951.
The Legislative Council Movement, 1933–1953
Authors: Davey Harold W.
Published: May 2006

Informed policy-making is the primary responsibility of any legislative body in a democracy. The policy-making task at all levels of government has become increasingly complex, technical and burdensome. This has been particularly evident in the years since the Great Depression. The demand for an increasing quantum of governmental services and functions at all levels and the competition among governmental units for revenue sources to finance public services have been chiefly responsible for magnifying the legislative burden. Hence it is surprising and disturbing that the people's policy-makers at the state level have been somewhat loath to reorganize their legislative processes and procedures to meet contemporary needs. Many “little Hoover” commissions have been busily engaged in recent years in attempting to modernize state administrative organization. No correspondingly vigorous effort has been made at legislative self-examination, although the need is at least equally pressing. Only ten states have annual legislative sessions, in spite of the fact that informed students of state government generally agree that the volume of legislative business in most states requires annual sessions.
Comparing Interest Group Scores across Time and Chambers: Adjusted ADA Scores for the U.S. Congress
Authors: Groseclose Tim , Levitt Steven D. , Snyder James M.
Published: May 2006

Interest group ratings are widely used in studies of legislative behavior. Since the set of votes used is not constant over time and across chambers, the scales underlying the scores can shift and stretch. We introduce an econometric model that corrects the problem. Specifically, we derive an index, much like an inflation index for consumer prices, that allows one to make intertemporal and interchamber comparisons of interest group ratings. The adjusted scores for the ADA show a strong liberal trend in the average member of Congress during 1947–94, followed by a conservative reversal. A nonparametric test using ADA and ACU scores demonstrates the validity of adjusted scores and the invalidity of nominal scores for intertemporal and interchamber comparisons. Using two studies (Levitt 1996; Shipan and Lowry 1997) we illustrate that the choice of adjusted versus nominal scores may greatly affect substantive conclusions of researchers.
Ethics and Politics: A Response to Terchek and Moore
Authors: Smith Thomas W.
Published: May 2006

I respond to Terchek and Moore by investigating the interrelationship of ethics to politics in Aristotle's thought. To this end I defend two claims. First, doing ethics requires understanding politics. Second, politics requires practical wisdom and ethics. Since even the politics wanted by Terchek and Moore requires these virtues, they are wrong to claim that my account of the common good, resting as it does on similar virtues, is impractical and dangerous.
A Convenient Preparation of Enantiomerically Pure (+)‐(1R,2R)‐ and (−)‐(1S,2S)‐1,2‐Diamino‐1,2‐diphenylethanes
Authors: Braddock D. Christopher , Redmond Joanna M. , Hermitage Stephen A. , White Andrew J. P.
Published: May 2006

A gram‐scale preparation of (1S,2S)‐ and (1R,2R)‐1,2‐diamino‐1,2‐diphenylethanes, (1S,2S)‐1 and (1R,2R)‐1, is reported via (±)‐iso‐amarine 4. Strategically, the activation of (±)‐iso‐amarine 4 for hydrolysis to the required diamines and enantiomeric resolution is achieved simultaneously by formation of two separable diastereoisomeric N‐acylamidines 5 and 6 derived from direct DCC‐mediated coupling of (±)‐iso‐amarine 4 with (R)‐acetylmandelic acid. iso‐Amarine 4 is conveniently obtained from amarine 3, and a one‐pot synthesis of the latter is reported from benzaldehyde and hexamethyldisilazane as catalysed by benzoic acid.
Highly Regioselective Friedel–Crafts Reactions of Electron‐Rich Aromatic Compounds with Pyruvate Catalyzed by Lewis Acid‐Base: Efficient Synthesis of Pesticide Cycloprothrin
Authors: Si Yu‐Gui , Chen Jun , Li Fan , Li Jin‐Hua , Qin Ye‐Jun , Jiang Biao
Published: May 2006

An efficient synthesis of aromatic lactate esters is reported via highly regioselective Friedel–Crafts reactions of electron‐rich aromatic compounds with pyruvate ester promoted by TiCl4 in the presence of basic Al2O3. The utility of the reaction is shown by the efficient synthesis of the pesticide cycloprothrin in high yield.
tert‐Butyl Ethers: Renaissance of an Alcohol Protecting Group. Facile Cleavage with Cerium(III) Chloride/Sodium Iodide
Authors: Bartoli Giuseppe , Bosco Marcella , Carlone Armando , Locatelli Manuela , Marcantoni Enrico , Melchiorre Paolo , Sambri Letizia
Published: May 2006

The tert‐butoxy derivative is one of the most underused alcohol protecting groups. After having developed an easy and useful protocol for its introduction, we offer here a simple procedure for its removal by treatment with anhydrous CeCl3 and NaI in CH3CN. The procedure led to the successful cleavage of aliphatic and aromatic tert‐butyl ethers and was compatible with various other functionalities and protecting groups present in the molecule.
Potassium Carbonate‐Catalyzed Reactions of Salicylic Aldehydes with Allenic Ketones and Esters: an Effective Way to Synthesize Functionalized 2H‐Chromenes
Authors: Shi Min , Dai Lun‐Zhi , Shi Yong‐Ling , Zhao Gui‐Ling
Published: May 2006

Potassium carbonate‐catalyzed reactions of salicylic aldehydes with 3‐methylpenta‐3,4‐dien‐2‐one, 3‐benzylpenta‐3,4‐dien‐2‐one or ethyl 2‐methylbuta‐2,3‐dienoate gave the corresponding functionalized 2H‐1‐chromenes in good to excellent yields and good stereoselectivities in some cases in DMSO at 120 °C within 1 h, respectively.
Cover Picture: Silica‐Based Mesoporous Organic–Inorganic Hybrid Materials (Angew. Chem. Int. Ed. 20/2006)
Authors: Hoffmann Frank , Cornelius Maximilian , Morell Jürgen , Fröba Michael
Published: May 2006

Like Honeycomb is how the pore structures of silica‐based mesoporous organic–inorganic hybrid materials often appear. In the Review on page 3216 ff., M. Fröba and co‐workers give an overview of their preparation. The cover picture shows hybrids whose pores are functionalized with cyclam (ligand), sulforhodamine B (laser die), and a cinchona derivative (for heterogeneous asymmetric catalysis). Particular attention is given to the class of periodic mesoporous organosilicas (PMOs).
Microspectroscopic fluorescence analysis with prism‐based imaging spectrometers: Review and current studies
Authors: Hanley Quentin S , Murray Patricia I , Forde Toni S
Published: May 2006

Background:

Fluorescence imaging spectroscopy is a powerful but under‐utilized tool. This article gives perspective on the use of imaging spectroscopy, and provides two examples of imaging spectroscopy done with a prism‐based system. The intent is to give insight into the power of imaging spectroscopy when used in combination with other imaging techniques. In particular, studies of intact coral photobleaching and beads designed to show energy transfer are reported. In the bead study, spectroscopic lifetime imaging was performed at each photobleaching step.

Results:

Spectroscopic photobleaching of the hard coral, Montastrea annularis, revealed two spectral regions. A region in the red portion of the spectrum bleached rapidly while progressively increasing fluorescence was observed over a wide portion of the spectrum. This behavior is consistent with current theories for the role of fluorescent proteins in corals.

Following a photobleaching study of beads designed to exhibit energy transfer with imaging spectroscopic fluorescence lifetime imaging microscopy (ISFLIM) allowed unambiguous assignment of fluorescence resonance energy transfer (FRET). The data in this experiment indicated that most of the commonly used markers of FRET would have been inconclusive. The ability of the ISFLIM to look at all regions of the spectrum, particularly the acceptor region, allowed FRET to be assigned.

Conclusions:

Fluorescence imaging spectroscopy is a rapidly advancing technology, uniquely suited to the flexible detection of dyes over a wide range of wavelengths. © 2006 International Society for Analytical Cytology
Digital image analysis of cytoskeletal F‐actin disintegration in renal microvascular endothelium following ischemia/reperfusion
Authors: Leemreis Jan R. , Versteilen Amanda M. G. , Sipkema Pieter , Groeneveld A. B. Johan , Musters René J. P.
Published: May 2006

Background:

Damaged and/or dysfunctional microvascular endothelium has been implicated in the pathogenesis of ischemic acute renal failure (ARF). Rapidly occurring changes in the endothelial F‐actin cytoskeleton as observed in vitro might be responsible, but have been proven difficult to measure accurately in situ. Therefore, the purpose of this study was to examine several methods of digital image analysis in order to quantify the alterations of endothelial F‐actin after renal ischemia and reperfusion (I/R), and to relate these to deterioration of renal function.

Methods:

Frozen sections of Sham and I/R rat kidneys were fixed in 4% formaldehyde and stained with rhodamine‐phalloïdin. Microvascular structures were captured using a 3i Marianas™ digital imaging fluorescence microscope workstation. Images were analyzed using 3i SlideBook™ software, employing several masking techniques and line‐scans.

Results:

Digital image analysis demonstrated a decrease in the mean intensity of rhodamine‐phalloïdin fluorescence after I/R from 1030 ± 187 to 735 ± 121 a.u. (arbitrary units, mean ± SD, n = 7). The number of F‐actin fragments per pixel increased from (15.8 ± 4.9) × 10−5 to (20.7 ± 3.5) × 10−5 (n = 7), indicating cytoskeletal fragmentation. In addition, line‐scan analysis demonstrated a disturbed spatial orientation of the F‐actin cytoskeleton after I/R. Finally, the loss of F‐actin correlated with a rise in plasma creatinine.

Conclusions:

The methods of digital image analysis described in the present study demonstrate that renal I/R induces profound changes in the F‐actin cytoskeletal structure of microvascular endothelial cells, implicating an injured and dysfunctional microvascular endothelium, which may contribute to acute renal failure (ARF). © 2006 International Society for Analytical Cytology
Nutritional knowledge of health care professionals working in the eating disorders
Authors: Cordery Helen , Waller Glenn
Published: May 2006

Background

Clinicians working in the eating disorders require a good working knowledge of basic nutrition. As different professional groups are trained in this knowledge to different degrees, it is not possible to assume that all clinicians working with the eating disorders have an equivalent knowledge base. The aim of this study is to determine the nutritional knowledge of different groups of professionals working with the eating disorders.

Method

The participants were 65 clinicians (dietitians, nurses, clinical psychologists, psychiatrists) working with the eating disorders and a group of 23 non‐clinicians. All participants completed a standardised measure of knowledge of nutritional content of a range of foodstuffs, plus a brief form of the Eating Disorders Inventory (EDI‐2).

Results

Dietitians had the highest level of knowledge regarding carbohydrate, protein and fat, but were no different to the other groups in their knowledge of fibre content. The psychiatrists were the next best informed. The clinical psychologists and nurses were no better than the lay group. Levels of knowledge about nutrition were unrelated to most personal characteristics, though there were some links to the clinician's own eating attitudes.

Conclusions

Given the central role of nutrition in treating the eating disorders, it is clearly important that teams include professionals with nutritional knowledge. These findings indicate that simple experience in the field is not sufficient to ensure such knowledge, and that specialised dietitians are more likely to be able to provide the necessary treatment resource. Therefore, multidisciplinary teams should include specialist dietetic input. Copyright © 2006 John Wiley & Sons, Ltd and Eating Disorders Association.
Surface analysis and biocorrosion properties of nanostructured surface sol–gel coatings on Ti6Al4V titanium alloy implants
Authors: Advincula Maria C. , Petersen Don , Rahemtulla Firoz , Advincula Rigoberto , Lemons Jack E.
Published: May 2006

Surfaces of biocompatible alloys used as implants play a significant role in their osseointegration. Surface sol–gel processing (SSP), a variant of the bulk sol–gel technique, is a relatively new process to prepare bioreactive nanostructured titanium oxide for thin film coatings. The surface topography, roughness, and composition of sol–gel processed Ti6Al4V titanium alloy coatings was investigated by atomic force microscopy (AFM) and X‐ray electron spectroscopy (XPS). This was correlated with corrosion properties, adhesive strength, and bioreactivity in simulated body fluids (SBF). Electroimpedance spectroscopy (EIS) and polarization studies indicated similar advantageous corrosion properties between sol–gel coated and uncoated Ti6Al4V, which was attributed to the stable TiO2 composition, topography, and adhesive strength of the sol–gel coating. In addition, inductive coupled plasma (ICP) and scanning electron microscopy with energy dispersive spectrometry (SEM‐EDS) analysis of substrates immersed in SBF revealed higher deposition of calcium and phosphate and low release rates of alloying elements from the sol–gel modified alloys. The equivalent corrosion behavior and the definite increase in nucleation of calcium apatite indicate the potential of the sol–gel coating for enhanced bioimplant applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Emotion as mediators of the relations between perceived supervisor support and psychological hardiness on employee cynicism
Authors: Cole Michael S. , Bruch Heike , Vogel Bernd
Published: May 2006

In this study we explore whether emotion experienced at work mediates the relationships between perceived supervisor support, psychological hardiness, and employee cynicism. Data were collected from employees working at a medical technology company located in Switzerland. Mediational analyses showed that employees' positive and negative emotions experienced amidst an organizational crisis fully accounted for the relations between perceived supervisor support and cynicism and psychological hardiness and cynicism. Practical implications and directions for future research are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Team mental models and team performance: a field study of the effects of team mental model similarity and accuracy
Authors: Lim Beng‐Chong , Klein Katherine J.
Published: May 2006

We conducted a field study of 71 action teams to examine the relationship between team mental model similarity and accuracy and the performance of real‐world teams. We used Pathfinder to operationalize team members' taskwork mental models (describing team procedures, tasks, and equipment) and teamwork mental models (describing team interaction processes) and examined team performance as evaluated by expert team assessment center raters. Both taskwork mental model and teamwork mental model similarity predicted team performance. Team mental model accuracy measures were also predictive of team performance. We discuss the implications of our findings and directions for future research. Copyright © 2006 John Wiley & Sons, Ltd.
Linewidth modelling of C2H2N2 mixtures tested by rotational CARS measurements
Authors: Buldyreva J. , Bonamy J. , Weikl M. C. , Beyrau F. , Seeger T. , Leipertz A. , Vestin F. , Afzelius M. , Bood J. , Bengtsson P.‐E.
Published: May 2006

The acetylene–nitrogen system is investigated in a combined theoretical and experimental effort in view of its thermometry applications. Accurate values of the rotational Raman linewidths of acetylene are of crucial importance for the computation of spectra from rotational coherent anti‐Stokes Raman scattering (CARS) used for temperature and concentration evaluations. Since the direct measurements of these linewidths are not available, they are rigorously calculated by a semi‐classical Robert–Bonamy formalism employing exact trajectories. The computed linewidths are used as input parameters in the theoretical spectra simulation, which is also improved by the inclusion of an interbranch interference with coherent Stokes Raman scattering (CSRS). These theoretical spectra are used to evaluate the temperature from experimental CARS spectra of acetylene‐nitrogen mixtures recorded in the pressure range 0.1–0.6 MPa. The new linewidths (NLWs) and the CSRS interference inclusion result in a clear improvement of spectral fitting as well as in reasonable values of evaluated temperatures. Copyright © 2006 John Wiley & Sons, Ltd.
Four‐photon Rayleigh‐wing spectroscopy of α‐chymotrypsin protein in water
Authors: Bunkin A. F. , Chikishev A. U. , Gorchakov A. P. , Nurmatov A. A. , Pershin S. M.
Published: May 2006

The low‐wavenumber spectra of CCl4, Milli‐Q water and aqueous solution of α‐chymotrypsin protein were measured using four‐photon coherent spectroscopy in the subterahertz range. Good coincidence of narrow peak positions in the four‐photon spectra of liquid CCl4 with the rotational frequencies in the gas phase was observed for the first time. A new sharp (width ∼0.6 cm−1) resonance at ∼3 cm−1 was observed in the aqueous protein solution, in contrast with water. This difference was interpreted as an exhibition of low‐wavenumber vibrations of large fragments of the protein molecule. Copyright © 2006 John Wiley & Sons, Ltd.
BOLD contrast sensitivity enhancement and artifact reduction with multiecho EPI: Parallel‐acquired inhomogeneity‐desensitized fMRI
Authors: Poser Benedikt A. , Versluis Maarten J. , Hoogduin Johannes M. , Norris David G.
Published: May 2006

Functional MRI (fMRI) generally employs gradient‐echo echo‐planar imaging (GE‐EPI) to measure blood oxygen level‐dependent (BOLD) signal changes that result from changes in tissue relaxation time T between activation and rest. Since T strongly varies across the brain and BOLD contrast is maximal only where the echo time (TE) equals the local T, imaging at a single TE is a compromise in terms of overall sensitivity. Furthermore, the long echo train makes EPI very sensitive to main field inhomogeneities, causing strong image distortion. A method is presented that uses accelerated parallel imaging to reduce image artifacts and acquire images at multiple TEs following a single excitation, with no need to increase TR. Sensitivity gains from the broadened T coverage are optimized by pixelwise weighted echo summation based on local T or contrast‐to‐noise ratio (CNR) measurements. The method was evaluated using an approach that allows differential BOLD CNR to be calculated without stimulation, as well as with a Stroop experiment. Results obtained at 3 T showed that BOLD sensitivity improved by 11% or more in all brain regions, with larger gains in areas typically affected by strong susceptibility artifacts. The use of parallel imaging markedly reduces image distortion, and hence the method should find widespread application in functional brain imaging. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Length scale hierarchy in sol, gel, and coacervate phases of gelatin
Authors: Mohanty Biswaranjan , Aswal V. K. , Kohlbrecher J. , Bohidar H. B.
Published: May 2006

Length scale hierarchy in gelatin sol, gel, and coacervate (induced by ethanol) phases, having same concentration of gelatin in aqueous medium (13% w/v), has been investigated through small angle neutron scattering and rheology measurements. The static structure factor profile, I(q) versus wave vector q, was found to be remarkably similar for all these samples. This data could be split into three distinct q‐regimes: the low‐q regime, Iex(q) = Iex(0)/(1+q2ζ2)2 valid for q < 3Rg−1; the intermediate q‐regime, I(q) = I(0)/(1+q2ξ2) for 3Rg−1 < q < ξ−1; and the asymptotic regime, I(q) = (c/q) exp(−Rc2q2/2) for q > ξ−1. Consequently, three distinct length scales could be deduced from structure factor data: (a) inhomogeneity of size, ζ = 20 ± 1 nm for all the three phases; (b) average mesh size, ξ0 = 2.6 ± 0.2 nm for sol and gel, and smaller mesh size, ξos = 1.2 ± 0.2 nm for coacervate; and (c) cross section of gelatin chains, Rc = 0.35 ± 0.04 nm. In addition, the structure factor data obtained from coacervating solution analyzed in the Guinier region, I(q) = exp(−q2Rg2/3), yielded value of typical radius of gyration of clusters, Rg ≈ 69 nm that indicated existence of triple‐helices of length, L ≈ 239 nm; (d) Frequency and temperature sweep measurements conducted on coacervate samples revealed two other length scales: (e) viscoelastic length, ξve = 14 ± 2 nm and (f) correlation length at melting, ξT = 500 ± 70 nm. Thus, existence of six distinct length scales, (a–f), ranging from 1.2 to 500 nm has been established in the coacervate phase of gelatin–ethanol–water system. Results are discussed within the framework of Landau‐Ginzburg treatment of dynamically asymmetric systems (Prog Theor Phys 1977, 57, 826; Phys Rev A 1991, 44, R817; J Phys II (France) 1992, 2, 1631). © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1653–1667, 2006
Coping and suicidality among homeless youth
Authors: Kidd Sean A. , Carroll Michelle R.
Published: May 2006

This study examined the impact of coping strategies employed by homeless youth upon suicidal ideation, suicide attempts on the streets, and feeling trapped/helpless. Coping strategies examined in the analysis included problem‐focused and avoidant coping, along with several coping strategies identified in previous exploratory qualitative studies. Greater risk was associated with avoidant coping, social withdrawal, use of drugs and alcohol as coping, with “belief in a better future” linked to lowered risk levels. Gender interactions emerged with respect to avoidant coping and social withdrawal, both of which served as greater contributors to risk levels among females. Several approaches to coping including problem‐focused strategies and strategies identified by youths in previous qualitative works emerged as not serving to ameliorate suicidality.
Hsp70 inhibits lipopolysaccharide‐induced NF‐κB activation by interacting with TRAF6 and inhibiting its ubiquitination
Authors: Chen Huaqun , Wu Yifan , Zhang Yiqing , Jin Lina , Luo Lan , Xue Bin , Lu Chen , Zhang Xiran , Yin Zhimin
Published: May 2006

Inducible heat shock protein 70 (Hsp70) is one of the most important HSPs for maintenance of cell integrity during normal cellular growth as well as pathophysiological conditions. Tumor necrosis factor receptor‐associated factor 6 (TRAF6) is a crucial signaling transducer that regulates a diverse array of physiological and pathological processes and is essential for activating NF‐κB signaling pathway in response to bacterial lipopolysaccharide (LPS). Here we report a novel mechanism of Hsp70 for preventing LPS‐induced NF‐κB activation in RAW264.7 macrophage‐like cells. Our results show that Hsp70 can associate with TRAF6 physically in the TRAF‐C domain and prevent TRAF6 ubiquitination. The stimulation of LPS dissociates the binding of Hsp70 and TRAF6 in a time‐dependent manner. Hsp70 inhibits LPS‐induced NF‐κB signaling cascade activation in heat‐shock treated as well as Hsp70 stable transfected RAW264.7 cells and subsequently decreases iNOS and COX‐2 expression. Two Hsp70 mutants, Hsp70ΔC(1–428aa) with N‐terminal ATPase domain and Hsp70C(428–642aa) with C‐terminal domain, lack the ability to influence TRAF6 ubiquitination and TRAF6‐triggered NF‐κB activation. Taken together, these findings indicate that Hsp70 inhibits LPS‐induced NF‐κB activation by binding TRAF6 and preventing its ubiquitination, and results in inhibition of inflammatory mediator production, which provides a new insight for analyzing the effects of Hsp70 on LPS‐triggered inflammatory signal transduction pathways.
VHA‐8, the E subunit of V‐ATPase, is essential for pH homeostasis and larval development in C. elegans
Authors: Ji Yon Ju , Choi Kyu Yeong , Song Hyun-Ok , Park Byung-Jae , Yu Jae-Ran , Kagawa Hiroaki , Song Woo Keun , Ahnn Joohong
Published: May 2006

Vacuolar H+‐ATPase (V‐ATPase) is an ATP‐dependent proton pump, which transports protons across the membrane. It is a multi‐protein complex which is composed of at least 13 subunits. The Caenorhabditis elegans vha‐8 encodes the E subunit of V‐ATPase which is expressed in the hypodermis, intestine and H‐shaped excretory cells. VHA‐8 is necessary for proper intestinal function likely through its role in cellular acidification of intestinal cells. The null mutants of vha‐8 show a larval lethal phenotype indicating that vha‐8 is an essential gene for larval development in C. elegans. Interestingly, characteristics of necrotic cell death were observed in the hypodermis and intestine of the arrested larvae suggesting that pH homeostasis via the E subunit of V‐ATPase is required for the cell survival in C. elegans.
para‐ and ortho‐Pyridinium aldoximes in reaction with acetylthiocholine
Authors: Šinko Goran , Čalić Maja , Kovarik Zrinka
Published: May 2006

In the oximolysis reaction para‐aldoximes K027 and TMB‐4 react faster with ATCh than ortho‐aldoximes HI‐6 and K033. The reaction rate constants at 25 °C were 22 M−1
min−1 for HI‐6 and K033, 230 M−1
min−1 for TMB‐4 and 306 M−1
min−1 for K027. Semi‐empirical calculations showed that differences in rates do not origin from different electron density on the oxygen of the oxime group, but can be explained by the steric hindrance of the oxime group within the molecule. Thermodynamic parameters, ΔG
#, ΔH
# and ΔS
#, were also determined for oximolysis reaction.
The effect of vortex pairing on particle dispersion and kinetic energy transfer in a two-phase turbulent shear layer
Authors: Kiger Kenneth T. , Lasheras Juan C.
Published: May 2006

The transport of heavy, polydispersed particles and the inter-phase transfer of kinetic energy due to the viscous drag forces is measured experimentally in a turbulent shear layer. To study the effect of the large-scale vortex pairing event, the shear layer is forced simultaneously with a fundarmental and subharmonic perturbation. It is shown that vortex pairing plays a homogenizing role on the particulate field, but hte amount of homogenization is strongly dependent upon the particle's viscous relaxtion time, the eddy turnover time, as well as the time the particles interact with each scale prior to a pairing event. Thus, even though the smaller size particles become well-mixed across the large eddies, the larger sizes are still dispersed in an inhormogeneous fashion. It is also found that the kinetic energy transfer between the phases occurs inhomogeneously with energy being exchanged predominantly in a sublayer just outside the region of maximum turbulence intensity. The kinetic energy transfer is shown to exhibit notable positive and negative peaks located beneath the cores and stagnation points of the large-scale eddy field, and these peaks are shown to result from the irrotational velocity perturbations created by the vortices. This energy exchange mechanism remains a prominent process as long as the Stokes number of the particles relative to the vortices is of order unity.
Shear velocity variation within the D″ region beneath the central Pacific
Authors: Avants Megan , Lay Thorne , Russell Sara A. , Garnero Edward J.
Published: May 2006

Small‐scale variability of shear velocity (Vs) structure in the D″ region beneath the central Pacific is imaged using 442 broadband tangential component S waveforms recorded in western North America for 37 intermediate and deep focus Tonga‐Fiji earthquakes. Double‐array stacking of spatially binned subsets of data reveals lateral variations in the relative timing and amplitude of deep mantle discontinuity reflections on scale lengths of about 130 km across the ∼6° × 8° region of D″ sampled. Waveform modeling using localized one‐dimensional structures indicates variations of the Vs increase at the D″ discontinuity ranging from 0.5% to 2.3%, and discontinuity depths ranging from 2490 to 2735 km, deepening and weakening from southwest‐to‐northeast across the study area. Two abrupt Vs reductions are also detected within the D″ layer. We thus present a laterally variable three‐layer model of the D″ region beneath the central Pacific. The complex structure may be associated with lateral thermal and chemical gradients that produce a lens of postperovskite material above an ultralow‐velocity zone on the margin of a large low shear velocity province.
Skewness of sea level variability of the world's oceans
Authors: Thompson Keith R. , Demirov Entcho
Published: May 2006

Skewness of sea level variability for the world's oceans is calculated using gridded altimeter data for the period 1993–2001. Many well‐known ocean features can be identified in the skewness map, including the Gulf Stream, Kuroshio Extension, Brazil‐Malvinas Confluence, and the Agulhas Retroflection. It is shown, through an idealized example and results from a quasi‐geostrophic model, that sea level skewness can be used to identify the mean path of unstable ocean jets and also regions dominated by eddies with a preferred sense of rotation. These ideas are confirmed with a more detailed analysis of the skewness fields for the northwest Atlantic and Agulhas Retroflection region. Finally, it is argued that sea level skewness, like variance, is a potentially powerful diagnostic for testing the realism of high‐resolution ocean circulation models.
Probabilistic inversion of a terrestrial ecosystem model: Analysis of uncertainty in parameter estimation and model prediction
Authors: Xu Tao , White Luther , Hui Dafeng , Luo Yiqi
Published: May 2006

The Bayesian probability inversion and a Markov chain Monte Carlo (MCMC) technique were applied to a terrestrial ecosystem model to analyze uncertainties of estimated carbon (C) transfer coefficients and simulated C pool sizes. This study used six data sets of soil respiration, woody biomass, foliage biomass, litterfall, C content in the litter layers, and C content in mineral soil measured under both ambient CO2 (350 ppm) and elevated CO2 (550 ppm) plots from 1996 to 2000 at the Duke Forest Free‐Air CO2 Experiment (FACE) site. A Metropolis‐Hastings algorithm was employed to construct a posterior probability density function (PPDF) of C transfer coefficients on the basis of prior information of model parameters, model structure, and the six data sets. The constructed PPDFs indicated that the transfer coefficients from pools of nonwoody biomass, woody biomass, and structural litter were well constrained by the six data sets under both ambient and elevated CO2. The data sets also gave moderate information to the transfer coefficient from the slow soil C pool. However, the transfer coefficients from pools of metabolic litter, microbe, and passive soil C were poorly constrained. The poorly constrained parameters were attributable to either the lack of experimental data or the mismatch of timescales between the available data and the parameters to be estimated. Cumulative distribution functions were constructed for simulated C pool sizes on the basis of the six data sets, showing that on average the ecosystem would store 16,616 g C m−2 at elevated CO2 by the year 2010, significantly higher than 13,426 g C m−2 at ambient CO2 with 95% confidence. This study shows that the combination of a Bayesian approach and MCMC inversion technique is an effective method to synthesize information from various sources for assessment of ecosystem responses to elevated CO2.
Combined MU radar and ozonesonde measurements of turbulence and ozone fluxes in the tropo‐stratosphere over Shigaraki, Japan
Authors: Gavrilov N. M. , Fukao S. , Hashiguchi H. , Kita K. , Sato K. , Tomikawa Y. , Fujiwara M.
Published: May 2006

Turbulent diffusivity and turbulent ozone fluxes in the tropo‐stratosphere are studied employing simultaneous observations with the Middle and Upper (MU) Atmosphere radar and ozonesondes in Shigaraki, Japan during April 16–24, 1998. A broad region around the tropopause was dynamically active. Maxima of turbulent diffusivity were observed at 8–14 km altitude. Such maxima may produce vertical turbulent ozone fluxes across the tropopause with magnitudes comparable to those required for the global ozone budget. Meso‐meteorological ozone intrusions may enhance the fluxes.
Disentangling the role of microphysical and dynamical effects in determining cloud properties over the Atlantic
Authors: Lohmann Ulrike , Koren Ilan , Kaufman Yoram J.
Published: May 2006

MODIS satellite data reveal that over the Atlantic Ocean (20°S–30°N) in June–August 2002 indirect aerosol effects cause a decrease in the cloud top effective radius of stratiform clouds of 2.9 μm and an increase in cloud fraction of 21%, when increasing the aerosol optical thickness (AOT) from the cleanest 5 percentile to an AOT of 0.2. Thus, indirect aerosol effects are responsible for 72% (−8.8 W m−2) of the −12.2 W m−2 decrease in the shortwave radiation at the top‐of‐the atmosphere (TOA). Global climate model simulations with and without indirect aerosol effects confirm a decrease in TOA shortwave cloud forcing of −9 W m−2 over the Atlantic from the cleanest to the highest AOT due to indirect aerosol effects. While MODIS shows an increase in cloud fraction due to aerosols, in the model aerosols cause primarily an increase in cloud water. Thus, unlike the analysis from MODIS, the increase in cloud fraction with increasing AOT is dominated by changes in dynamical regimes, not by aerosol indirect effects.
On tracer boundary conditions for geophysical reservoirs: How to find the boundary concentration from a mixed condition
Authors: Haine T. W. N.
Published: May 2006

For several reasons, it is important to know the boundary concentration, a Dirichlet boundary condition, of a dynamically passive tracer entering an advective/diffusive flow. For example, the powerful theory of transit time distributions, which gives valuable insight into transport processes, needs this information in order to be applied to the tracer in question. Often, tracers of practical interest have a different kind of boundary condition, however, where a linear combination of the boundary tracer flux and the boundary tracer concentration is known: a Robin, or mixed, boundary condition. Computing the boundary concentration in these cases is therefore an important problem that is addressed here. A type of tracer Green's function called a boundary condition kernel provides the solution. The article explains several generic approaches to finding this function for analytic and discretized cases. Explicit solutions for the boundary condition kernel are given for advective/diffusive flow in a pipe and diffusive transport in a layer with time‐ and space‐varying diffusivity. These examples are applied to chlorofluorocarbon uptake by the ocean, anthropogenic carbon uptake by the ocean, and the statistical properties of sea surface temperature anomalies, but the fundamental ideas apply to tracer uptake by any geophysical reservoir.
Anomalous radiocarbon ages for foraminifera shells
Authors: Broecker Wallace , Barker Stephen , Clark Elizabeth , Hajdas Irka , Bonani Georges
Published: May 2006

The causes for discordant radiocarbon results on multiple species of planktonic foraminifera from high‐sedimentation‐rate marine sediments are investigated. We have documented two causes for these anomalous results. One is the addition of secondary radiocarbon for which we have, to date, only one firm example. It involves an opal‐rich sediment. The other is the incorporation of reworked material. Again, we have, to date, only one firm example. It involves a rapidly deposited ocean margin sediment. However, we have three other examples where reworking is the most likely explanation. On the basis of this study it is our conclusion that, where precise radiocarbon dating of high‐deposition‐rate marine sediment is required, a prerequisite is to demonstrate that concordant ages can be obtained on pairs of fragile and robust planktic shells. For sediment rich in opal, it is advisable to check for secondary calcite by comparing ages obtained on acid‐leached samples with those on unleached samples.
The effect of pressure on the structure and volume of ferromagnesian post‐perovskite
Authors: Mao Wendy L. , Mao Ho‐kwang , Prakapenka Vitali B. , Shu Jinfu , Hemley Russell J.
Published: May 2006

We determined pressure‐volume (P‐V) data for (Mg0.6Fe0.4)SiO3 post‐perovskite (ppv) upon decompression from 140 GPa. The data can be divided into four regions: above 95 GPa, diffraction peaks are sharp and follow a smooth and tight P‐V curve; below 90 GPa, peak widths increase, and a kink develops in the P‐V curve; below 60 GPa, the broadening plateaus; below 4.6 GPa, the ppv pattern disappears. This suggests that defects and stacking faults start to develop in ppv at 90 GPa and saturate at 60 GPa, and the structure disintegrates below 4.6 GPa. The volume and density of the (Mg0.6Fe0.4)SiO3 ppv is well constrained by our data at the pressures relevant to the Earth's D″ layer. Our bulk modulus in this region is much higher than theoretical calculations for pure MgSiO3 ppv.
Transport optimization in stellarators
Authors: Mynick H. E.
Published: May 2006

A survey of the approaches which have been developed for mitigating transport in stellarators is presented. A primary deficiency of stellarators has been elevated transport levels due to their nonaxisymmetry. Since the early 1980s, stellarator research has addressed this difficulty, developing a range of techniques for reducing transport, both neoclassical and, more recently, also anomalous. Several of these approaches are now being implemented in a new generation of experiments in the United States and abroad. This paper describes the fundamental physics of these methods for transport reduction.
Excitation of nanoscale vapor bubbles at the surface of gold nanoparticles in water
Authors: Kotaidis V. , Dahmen C. , von Plessen G. , Springer F. , Plech A.
Published: May 2006

Intense nonequilibrium femtosecond laser excitation of gold nanoparticles in water leads to a transient heating of the nanoparticles, which decays via heat transfer to the water phase. It is shown that the water temperature rises to near the critical temperature and the water undergoes an explosive evaporation in the subnanosecond range. The formation of vapor bubbles shows a threshold dependence on laser fluence. The nascent nanoscale vapor bubbles change the heat dissipation drastically. The nanoscale structure is resolved directly with a combination of x-ray scattering methods sensitive to the particle lattice expansion and the change in the water structure factor.
Hydration of ion-biomolecule complexes: Ab initio calculations and gas-phase vibrational spectroscopy of K+(indole)m(H2O)n
Authors: Miller Dorothy J. , Lisy James M.
Published: May 2006

In recent years neutral indole(H2O)n clusters have been used to model the hydration of biomolecules containing an indole moiety. Both experimental and theoretical studies of the binary indole⋯OH2 system show NH⋯OH σ hydrogen-bonding. By introducing a cation to the indole⋯OH2 model, cation⋯π and ion⋯dipole electrostatic interactions are placed in direct competition with conventional indole⋯OH2 hydrogen-bonding. The effects, arising from a monovalent potassium cation on (indole)m(H2O)n clusters, were investigated using infrared photodissociation spectroscopy in the OH and NH stretching regions. In K+(indole)1(H2O)n⩽4 and K+(indole)2(H2O)m⩽3 clusters, the electrostatic ion⋯ligand interaction inhibits the formation of an indole NH⋯OH2 σ hydrogen-bond. However, indole⋯H2O π hydrogen-bonding via the five-membered indole ring is observed with three or more ligands around the ion.
Molecular dynamics simulation of polymer electrolytes based on poly(ethylene oxide) and ionic liquids. I. Structural properties
Authors: Costa Luciano T. , Ribeiro Mauro C. C.
Published: May 2006

Molecular dynamics (MD) simulations have been performed for prototype models of polymer electrolytes in which the salt is an ionic liquid based on 1-alkyl-3-methylimidazolium cations and the polymer is poly(ethylene oxide), PEO. The MD simulations were performed by combining the previously proposed models for pure ionic liquids and polymer electrolytes containing simple inorganic ions. A systematic investigation of ionic liquid concentration, temperature, and the 1-alkyl- chain length, [1,3-dimethylimidazolium]PF6, and [1-butyl-3-methylimidazolium]PF6, effects on resulting equilibrium structure is provided. It is shown that the ionic liquid is dispersed in the polymeric matrix, but ionic pairs remain in the polymer electrolyte. Imidazolium cations are coordinated by both the anions and the oxygen atoms of PEO chains. Probability density maps of occurrences of nearest neighbors around imidazolium cations give a detailed physical picture of the environment experienced by cations. Conformational changes on PEO chains upon addition of the ionic liquid are identified. The equilibrium structure of simulated systems is also analyzed in reciprocal space by using the static structure factor, S(k). Calculated S(k) display a low wave-vector peak, indicating that spatial correlation in an extended-range order prevail in the ionic liquid polymer electrolytes. Long-range correlations are assigned to nonuniform distribution of ionic species within the simulation box.
Digital oxide deposition of SiO2 layers for III-nitride metal-oxide-semiconductor heterostructure field-effect transistors
Authors: Adivarahan V. , Rai S. , Tipirneni N. , Koudymov A. , Yang J. , Simin G. , Asif Khan M.
Published: May 2006

We present a digital-oxide-deposition (DOD) technique to deposit high quality SiO2 dielectric layers by plasma-enhanced chemical vapor deposition using alternate pulses of silicon and oxygen precursors. The DOD procedure allows for a precise thickness control and results in extremely smooth insulating SiO2 layers. An insulating gate AlGaN∕GaN heterostructure field-effect transistor (HFET) with 8nm thick DOD SiO2 dielectric layer had a threshold voltage of −6V (only 1V higher than that of regular HFET), very low threshold voltage dispersion, and output continuous wave rf power of 15W∕mm at 55V drain bias.
Compact UHV system for fabrication and in situ analysis of electron beam deposited structures using a focused low energy electron beam
Authors: Kakefuda Y. , Yamashita Y. , Mukai K. , Yoshinobu J.
Published: May 2006

A compact UHV system was developed in order to fabricate and analyze micro- and nanostructures on surfaces in situ. The system includes a low energy electron gun which provides a minimum spot size of ∼25nm in a diameter using electrostatic lenses, a cylindrical mirror analyzer for Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS), a low energy electron diffraction (LEED) optics, and a scintillation counter for scanning electron microscopy. Thus, we can analyze electronic states of specific microstructures on surfaces. In addition, we can fabricate microscopic structures artificially by means of scanning a focused electron beam. In this article, first we show the performance of the present analysis system. Next, we provide an example of the fabrication of iron microstructures by electron-induced deposition of iron pentacarbonyl [Fe(CO)5]. We successfully analyzed the amount and chemical states of deposited iron by AES in situ. We also investigated coverage dependence of electronic structure and surface periodic structure by EELS and LEED measurements, respectively. Thus, this system enables us to fabricate and analyze microscopic structures on surfaces in situ.
Enhanced magnetoelectric effect in Terfenol-D and flextensional cymbal laminates
Authors: Guo S. S. , Lu S. G. , Xu Z. , Zhao X. Z. , Or S. W.
Published: May 2006

A magnetoelectric (ME) laminate configuration was fabricated using a flextensional cymbal located between two magnetostrictive Terfenol-D (Tb1−xDyxFe2) plates. The laminate, operating in transverse magnetized/transverse polarized mode, has a ME voltage coefficient of 56.8mV∕Oe under a magnetic bias field of 1kOe, which is larger than that of conventional Terfenol-D/PZT/Terfenol-D configuration. It is believed that the enhancement of ME effect is due to the coupling between the magnetostriction of Terfenol-D and the high piezoelectric response of cymbal.
Effects of the substitution of Pb for Ba in (Ba,Sr)TiO3 films on the temperature stability of the tunable properties
Authors: Xia Yidong , Cai Cong , Zhi Xiaoyuan , Pan Bai , Wu Di , Meng Xiangkang , Liu Zhiguo
Published: May 2006

The tunable property and thermal stability of (Ba0.25Pb0.25)Sr0.5TiO3 films derived by pulsed laser deposition have been investigated. The substitution of Pb for Ba in (Ba,Sr)TiO3 (BST) system has been revealed to raise the transition temperature close to room temperature (RT) and enhance the tuning property. It is proposed that nanopolar regions would occur in the films in the paraelectric state at RT, arising from the addition of Pb2+ into the A site of pervoskite structure of BST. This induces the relaxor behavior and diffuse phase transition. Hence, low temperature-dependent tunability is obtained due to the broadening of dielectric constant peak. These results demonstrated that Pb substitution could be a simple and effective method to obtain high tunability and good temperature stability simultaneously.
Reduction of Arsenates by Humic Materials
Authors: Palmer Noel E. , Freudenthal John H. , von Wandruszka Ray
Published: May 2006

Environmental Context.Reduction of arsenic(v) to arsenic(iii) in the environment is of interest because of the greater toxicity and mobility of the latter. It is important to know to what extent humic materials (which are ubiquitous in soils) can act as abiotic reducing agents, and what factors influence their actions.
Abstract.Inorganic arsenates were found to be reduced to arsenite by homogeneous aqueous solutions of several humic and fulvic acids. Because of the concentration dependence of the redox potentials of humics, reduction was shown to be less likely in more concentrated solutions. This was especially true in higher pH ranges, and varied with the type of material used. Ion chromatography, validated by inductively coupled plasma mass spectrometry, was used to speciate arsenic after exposure to aqueous humates and fulvates. Reduction of As(v) proceeded in the 20–60% range, depending on the humic or fulvic acid used. The fraction of arsenate that was reduced initially increased with humic concentration, but leveled off as the reduction potential decreased at higher concentrations. Re-oxidation of As(iii) in humic solutions could be achieved by extended bubbling with air. Reduction capacities of two humates tested, as measured by I2 titration, were found to be significantly different.