bluuebunny/crossref_metadata_2025 huggingface dataset:
The mechanism of proton exclusion in aquaporin channels
Authors: Ilan Boaz , Tajkhorshid Emad , Schulten Klaus , Voth Gregory A.
Published: March 2004

The mechanism of proton exclusion in aquaporin channels is elucidated through free energy calculations of the pathway of proton transport. The second generation multistate empirical valence bond (MS‐EVB2) model was applied to simulate the interaction of an excess proton with the channel environment. Jarzynski's equality was employed for rapid convergence of the free energy profile. A barrier sufficiently high to block proton transport is located near the channel center at the NPA motif—a site involved in bi‐orientational ordering of the embedded water‐wire in absence of the excess proton. A second and lower barrier is observed at the selectivity filter near the periplasmic outlet where the channel is narrowest. This secondary barrier may be essential in filtering other large solutes and cations. Proteins 2004;9999:000–000. © 2004 Wiley‐Liss, Inc.
Different propensity to form amyloid fibrils by two homologous proteins—Human stefins A and B: Searching for an explanation
Authors: Jenko Saša , Škarabot Miha , Kenig Manca , Gunčar Gregor , Muševič Igor , Turk Dušan , Žerovnik Eva
Published: March 2004

By using ThT fluorescence, X‐ray diffraction, and atomic force microscopy (AFM), it has been shown that human stefins A and B (subfamily A of cystatins) form amyloid fibrils. Both protein fibrils show the 4.7 Å and 10 Å reflections characteristic for cross β‐structure. Similar height of ∼3 nm and longitudinal repeat of 25–27 nm were observed by AFM for both protein fibrils. Fibrils with a double height of 5.6 nm were only observed with stefin A. The fibril's width for stefin A fibrils, as observed by transmission electron microsopy (TEM), was in the same range as previously reported for stefin B (Žerovnik et al., Biochem Biophys Acta 2002;1594:1–5). The conditions needed to undergo fibrillation differ, though. The amyloid fibrils start to form at pH 5 for stefin B, whereas in stefin A, preheated sample has to be acidified to pH < 2.5. In both cases, adding TFE, seeding, and alignment in a strong magnetic field accelerate the fibril growth. Visual analysis of the three‐dimensional structures of monomers and domain‐swapped dimers suggests that major differences in stability of both homologues stem from arrangement of specific salt bridges, which fix α‐helix (and the α‐loop) to β‐sheet in stefin A monomeric and dimeric forms. Proteins 2004;55:000–000. © 2004 Wiley‐Liss, Inc.
New vision of emergency response planning
Authors: Al‐qurashi Fahad
Published: March 2004

In an emergency situation, seconds can mean the difference between relief and tragedy. Important information must be presented clearly and cohesively to enable decision making under crisis conditions.

This paper describes a project in which an Emergency Response System (ERS) has been developed for the Uthmaniyah gas plant (UGP). The ERS is essentially made up of two applications: the SAFER Real‐Time application made by SAFER Systems of the United States and a customized Geographical Information System (GIS) application developed by the Saudi Aramco Information Technology group. The SAFER system provides the user with immediate plume graphics based on local topography, maps, real‐time weather, chemical release specifics, and gas sensors data. This information is fed to a scientific gas dispersion model to predict the movement and concentration of gas or liquid release. The GIS allows the effect of the plume on people and structures to be analyzed in detail. Combined together, the ERS provides a tool for modeling and monitoring an accidental release. It will improve emergency planning, decision making, and response within the UGPD.

The above information is shared with emergency responders such as the fire department, security, and medical personnel via the network. As a result, they would dispatch their resources via the safest route. As weather conditions change, the plume dispersion will change and, hence, emergency response efforts will shift accordingly. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 56–61, 2004
Ferromagnetism of amorphous LaCo2 hydride
Authors: Nakamura H. , Nakahara A. , Shiga M. , Ito K. , Yamaguchi M. , Tsvyashchenko A. V. , Fomicheva L. N.
Published: March 2004

Magnetic properties of hydrogen‐amorphized LaCo2 with a relatively high hydrogen concentration, LaCo2H3.8, were investigated by magnetization and NMR measurements. The hydride behaves as a ferromagnet with TC = 400–500 K and averaged moment ∼0.5 μB/Co (at 1.5 K). The Co moment amplitude was found to distribute considerably from 0 to ∼1 μB. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Specific heat anomalies in ferroelectrics LiNaGe4O9 and Li1.1Na0.9Ge4O9
Authors: Cach R. , Cebula I. , Volnyanskii M. D.
Published: March 2004

The heat capacity of LiNaGe4O9 and Li1.1Na0.9Ge4O9 crystals has been measured using AC calorimetry method. It is shown, that the temperature evolution of the excess heat capacity and the excess entropy of both crystals, in the ferroelectric phase, can be described by the formulas resulting from the classical Landau theory of phase transition. The values of the Landau expansion coefficients are determined. The obtained results lead to the conclusion that the spontaneous polarization can be reckoned as an order parameter in the phase transition of the weak ferroelectric LiNaGe4O9. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Luminescence and defects creation in Ce3+‐doped Lu3Al5O12 crystals
Authors: Blazek K. , Krasnikov A. , Nejezchleb K. , Nikl M. , Savikhina T. , Zazubovich S.
Published: March 2004

Luminescence, energy transfer and defects creation processes were studied at 4.2–300 K for Ce3+‐doped Lu3Al5O12 crystals under excitation in the 2.5–11.5 eV energy range. The results obtained were compared with the characteristics of Y3Al5O12:Ce crystals. It was concluded that in both systems the efficiency of energy transfer from the host lattice to the impurity ion can be noticeably increased by the decrease of concentration of the defects responsible for their intrinsic luminescence. The origin of the optically created defects and possible mechanisms of their formation are discussed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conditions and possible mechanism of condensation of e–h pairs in bulk GaAs at room temperature
Authors: Vasil'ev Peter P.
Published: March 2004

A mechanism of the condensation of e–h pairs in bulk GaAs at room temperature, which has been observed earlier, is proposed. The point is that the photon assisted pairing happens in a system of electrons and holes that occupy energy levels at the very bottoms of the bands. Due to a very high e–h density, the destruction of the pairs and loss of coherence does not occur because almost all energy levels inside a 30–60 meV band from the bottom of the conduction band prove to be occupied. As a result, a coherent ensemble of composite bosons (paired electrons and holes) with the minimum possible energy appears. The lifetime of this strongly non‐equilibrium coherent e–h BCS‐like state is as short as a few hundred of femtoseconds. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Model exchange‐spring nanocomposite magnetic grains
Authors: Szlaferek A.
Published: March 2004

The magnetization reversal in nanocomposite two‐phase grains embedded in a soft magnetic matrix is calculated using Brown's equation. The grains are spherical, consisting of a soft core surrounded by a hard shell. The calculation yields nonlinear algebraic expressions whose solutions describe the nucleation field as a function of the geometrical and magnetic parameters of the grains. The magnetization reversal depends not only on the total grain size but also on the shell thickness. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectral representation theory for higher order nonlinear responses in random composites with arbitrary nonlinearity
Authors: Gu Liping , Gao Lei , Li Zhenya
Published: March 2004

The higher order nonlinear responses of random two‐phase composite media are investigated within spectral representation theory. The first component with the volume fraction p is assumed to have the nonlinear displacement (D)‐electric field (E) relation of the form D = ε1E+ χ1 |E|βE, where ε1 is the linear dielectric constant and χ1 is the (β + 1)th order nonlinear response; the second component is linear with the volume fraction 1–p and the dielectric constant ε2. The effective nonlinear responses of the composite media can be defined as 〈D〉 = εeE0 + χe|E0|βE0 + ηe|E0|2βE0, where εe, χe and ηe are the effective linear dielectric constant, the effective (β + 1)th order nonlinear response and (2β + 1)th order nonlinear response respectively. Based on spectral representation theory and the perturbative expansion method, general expressions for χe and ηe are derived as a function of the material parameters and the spectral density function m(x), which are indeed valid for arbitrary β and for any complicated microstructures. For the dilute limit and the Maxwell‐Garnett microstructures, our expressions yield the same formulae as those in previous works. Moreover, the theoretical results for Bruggeman effective medium microstructures are compared with numerical simulations, good agreement is found. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two deltons: An inseparable Schrödinger equation
Authors: Caylor McKinney Paul
Published: March 2004

Inseparable Schrödinger equations usually cannot be solved analytically. Most often their solutions are obtained numerically. It would be helpful to have an inseparable Schrödinger equation whose solution can be completely calculated. Perhaps more can be learned about appropriate wave function solutions of complex problems if the solutions of an inseparable Schrödinger equation, solved in terms of simple functions, are available. Such a study is possible using the Dirac delta function as the potential energy for two particles moving on a line. The Dirac delta function problem leads naturally to a consideration of the wave functions' symmetry properties. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Tandem mass spectrometry of half‐generation PAMAM dendrimer anions
Authors: He Min , McLuckey Scott A.
Published: March 2004

Ions derived from negative electrospray ionization of polyamidoamine (PAMAM) dendrimer generation 0.5 were subjected to ion trap tandem mass spectrometry. Ion/ion proton transfer reactions were used to manipulate the charge states of PAMAM precursor ions to form lower charge states from those initially formed by electrospray, as well as to facilitate the interpretation of the product ion mass spectra. Most of the products derived from dendrimer precursor ions could be rationalized by retro‐Michael decomposition reactions. The dominant fragmentation channels are highly dependent on the composition of the counter‐ions, which in this case are restricted to different numbers of sodium ions and protons, and whether the precursor ion is multiply charged or singly charged. An interpretation is given that is consistent with all of the observations made with the various anions associated with this study. The nature of the structural information that can be obtained via ion trap tandem mass spectrometry of the dendrimers is dependent on the types of precursor ions subjected to study. The tandem mass spectrometry data also provided information about the structure of faulty synthesis products present in the PAMAM dendrimer sample. Copyright © 2004 John Wiley & Sons, Ltd.
H∞tracking of linear continuous‐time systems with stochastic uncertainties and preview
Authors: Gershon E. , Shaked U. , Yaesh I.
Published: March 2004

The problem of finite‐horizonH∞tracking for linear continuous time‐invariant systems with stochastic parameter uncertainties is investigated for both, the state‐feedback and the output‐feedback control problems. We consider three tracking patterns depending on the nature of the reference signal i.e. whether it is perfectly known in advance, measured on line or previewed in a fixed time‐interval ahead. The stochastic uncertainties appear in both the dynamic and measurement matrices of the system. In the state‐feedback case, for each of the above three cases a game theory approach is applied where, given a specific reference signal, the controller plays against nature which chooses the initial condition and the energy‐bounded disturbance. The problems are solved using the expected value of the standard performance index over the stochastic parameters, where, in the state‐feedback case, necessary and sufficient conditions are found for the existence of a saddle‐point equilibrium. The corresponding infinite‐horizon time‐invariant tracking problem is also solved for the latter case, where a dissipativity approach is considered. The output‐feedback control problem is solved as a max–min problem for the three tracking patterns, where necessary and sufficient condition are obtained for the solution. The theory developed is demonstrated by a simple example where we compare our solution with an alternative solution which models the tracking signal as a disturbance. Copyright © 2004 John Wiley & Sons, Ltd.
H∞ preview tracking in output feedback setting
Authors: Kojima Akira , Ishijima Shintaro
Published: March 2004

The performance of preview control is investigated in terms of H∞‐criterion. In the output feedback setting, an H∞ preview control problem is discussed and the analytic solution is characterized by introducing matrix Riccati equations. The strength and the limitation of the H∞ preview performance are illustrated with numerical examples. Copyright © 2004 John Wiley & Sons, Ltd.
Angle‐resolved XPS of fluorinated and semi‐fluorinated side‐chain polymers
Authors: Beamson G. , Alexander M. R.
Published: March 2004

Angle‐resolved XPS data (elemental quantification and high‐energy‐resolution C 1s) are presented for ten polymers with side‐chains of the form OCO(CF2)yF, COO(CH2)2OCO(CF2)yF (y = 1, 2, 3) and COO(CH2)x(CF2)yF (x = 1, y = 1, 2, 3; x = 2, y = 8). Particular attention was paid to charge compensation and speed of data acquisition, with co‐addition from multiple fresh samples to give spectra with good energy resolution and good signal‐to‐noise ratio free from the effects of x‐ray‐induced degradation. Water contact angles for the polymers are also reported. The XPS data demonstrate preferential surface segregation of fluorine‐containing groups for all but the shortest side‐chain polymer, where the OCOCF3 side‐chain either does not surface segregate or is too short for surface segregation to be detectable by angle‐resolved XPS. In the other polymers studied the relative positions of functional groups in the side‐chains correlate with the angle‐resolved behaviour of the corresponding C 1s components. This shows that the surface side‐chains are oriented towards the polymer surface. For the COO(CH2)2OCO(CF2)yF (y = 1) side‐chain, the angle‐resolved C 1s data suggest reduced ordering and linearity compared with y = 2 and 3. For any particular series of polymers, e.g. COO(CH2)x(CF2)yF, the water contact angles increase with y, consistent with burying of the hydrophilic ester groups as y increases. For any particular value of y the sequence of water contact angles is COO(CH2)x(CF2)yF > OCO(CF2)yF ∼ COO(CH2)2OCO(CF2)yF, suggesting greater ordering and density of fluorocarbon species at the surface of the COO(CH2)x(CF2)yF side‐chain polymers compared with the other polymers studied. For the COO(CH2)2(CF2)8F polymer a water contact angle of 124° is measured, which is greater than that of poly(tetrafluoroethene). The COO(CH2)2OCO(CF2)F polymer is unusual in that it shows a particularly low water contact angle (83° ), suggesting that the probe fluid is able to sense both ester groups, consistent with the reduced ordering of the side‐chain detected by angle‐resolved XPS. Copyright © 2004 John Wiley & Sons, Ltd.
Comparative study of self‐assembly of a range of monofunctional aliphatic molecules on magnetron‐sputtered aluminium
Authors: Liakos Ioannis L. , Newman Roger C. , McAlpine Eoghan , Alexander Morgan R.
Published: March 2004

The adsorption of a range of organic molecules from toluene onto the oxidized surface of magnetron‐sputtered aluminium metal is studied using sessile drop water contact angle measurements. Molecules with different head group functionalities and various chain lengths are considered, including alkyl carboxylic acids, alkyl phosphonic acids, alkyl amines, alkyl trimethoxysilanes, alkyl trichlorosilanes and epoxy alkanes. Alkyl phosphonic and carboxylic acids are identified as readily forming the most well‐packed monolayers on the aluminium surface, whereas the others adsorb less well and the chlorosilanes polymerize as a result of combination with moisture to form a thick deposit. The high‐adsorption‐density monolayers of alkyl phosphonic and carboxylic acids were studied using polarization modulation infrared reflection–absorption spectroscopy (PM‐IRRAS) and x‐ray photoelectron spectroscopy (XPS): PM‐IRRAS reveals relatively poorer ordering of the C10 alkyl carboxylic acid monolayer compared with that formed from the phosphonic acid, and XPS data suggest that this is likely to relate to a lower ability to displace preadsorbed volatile organic compounds. Copyright © 2004 John Wiley & Sons, Ltd.
Remarks
Authors: Summers Lawrence H.
Published: March 2004

If the battle for America's future is going to be won, it is not going to be won only in the six‐hour school day.
Cloning and functional characterization of the SUR2/SYR2 gene encoding sphinganine hydroxylase in Pichia ciferrii
Authors: Bae Jung‐Hoon , Sohn Jung‐Hoon , Park Chang‐Seo , Rhee Joon‐Shick , Choi Eui‐Sung
Published: March 2004

Saccharomyces cerevisiae sphinganine C4‐hydroxylase encoded by the SUR2 gene catalyses the conversion of sphinganine to phytosphingosine. We isolated the SUR2 gene from Pichia ciferrii using nucleotide sequence homology to S. cerevisiae SUR2 to study hydroxylation of sphinganine in the sphingoid base overproducing yeast P. ciferrii. A positive clone was confirmed by nucleotide sequencing. A syringomycin‐E resistance phenotype of a S. cerevisiae sur2‐null mutant was complemented by expression of the cloned P. ciferrii SUR2 gene. Restoration of phytosphingosine production in the complemented strain was also confirmed, indicating that the cloned gene is a functional homologue of S. cerevisiae SUR2. The nucleotide sequence of the P. ciferrii SUR2 gene was submitted to GenBank under Accession No. AY151276. Copyright © 2004 John Wiley & Sons, Ltd.
On localized Kelvin‐Voigt damping
Authors: Renardy M.
Published: March 2004

We consider one‐dimensional wave propagation through two layers consisting, respectively, of an elastic and a viscoelastic medium. The viscoelastic medium is of Kelvin‐Voigt type. We assume that the material coefficients change smoothly without a discontinuity near the interface. It is proved that the decay rate of high frequency modes tends to infinity with frequency.
Induction of AApoAII amyloidosis by various heterogeneous amyloid fibrils
Authors: Fu Xiaoying , Korenaga Tatsumi , Fu Li , Xing Yanming , Guo Zhanjun , Matsushita Takatoshi , Hosokawa Masanori , Naiki Hironobu , Baba Satoshi , Kawata Yasushi , Ikeda Shu-ichi , Ishihara Tokuhiro , Mori Masayuki , Higuchi Keiichi
Published: March 2004

Preformed amyloid fibrils accelerate conformational changes of amyloid precursor proteins and result in rapid extension of amyloid fibrils in vitro. We injected various kinds of amyloid fibrils into mice with amyloidogenic apoAII gene (Apoa2C
). The most severe amyloid depositions were detected in the tissues of mice injected with mouse AApoAII(C) amyloid fibrils. Mild amyloid depositions were also detected in the tissues of mice that were injected with other types of fibrils, including synthetic peptides and recombinant proteins. However, no amyloid depositions were found in mice that were injected with non‐amyloid fibril proteins. These results demonstrated that a common structure of amyloid fibrils could serve as a seed for amyloid fibril formation in vivo.
HIV‐1 auxiliary regulatory protein Vpr promotes ubiquitination and turnover of Vpr mutants containing the L64P mutation
Authors: Zhao Ling-Jun , Jian Heng , Zhu Henghu
Published: March 2004

The auxiliary regulatory protein Vpr of HIV‐1 possesses several biological activities which are believed to facilitate HIV‐1 replication and pathogenesis. In this report, experimental evidence suggests a novel biological activity of Vpr: facilitation of the turnover of Vpr mutants bearing the L64P mutation. This novel activity of Vpr was shared by Vpr molecules from different subtypes of HIV‐1. Co‐expression of the wild type Vpr with the VprW54A/L64P mutant resulted in normal synthesis of the mutant mRNA but enhanced ubiquitination and turnover of the mutant protein. These results suggest that Vpr may interact with the ubiquitin/proteasome pathway to regulate the stability of viral or cellular proteins.
The critical role of tryptophan‐116 in the catalytic cycle of dimethylsulfoxide reductase from Rhodobacter capsulatus
Authors: Ridge Justin P , Aguey-Zinsou Kondo-Francois , Bernhardt Paul V , Hanson Graeme R , McEwan Alastair G
Published: March 2004

In dimethylsulfoxide reductase of Rhodobacter capsulatus tryptophan‐116 forms a hydrogen bond with a single oxo ligand bound to the molybdenum ion. Mutation of this residue to phenylalanine affected the UV/visible spectrum of the purified MoVI form of dimethylsulfoxide reductase resulting in the loss of the characteristic transition at 720 nm. Results of steady‐state kinetic analysis and electrochemical studies suggest that tryptophan 116 plays a critical role in stabilizing the hexacoordinate monooxo MoVI form of the enzyme and prevents the formation of a dioxo pentacoordinate MoVI species, generated as a consequence of the dissociation of one of the dithiolene ligands of the molybdopterin cofactor from the Mo ion.
Role of protein kinase R in double‐stranded RNA‐induced expression of nitric oxide synthase in human astroglia
Authors: Auch Corey J , Saha Ramendra N , Sheikh Faruk G , Liu Xiaojuan , Jacobs Bertram L , Pahan Kalipada
Published: March 2004

Environmental factor(s), such as viral infection, has been implicated as one of the triggering events leading to neuroinflammation in multiple sclerosis. This study underlines the importance of double‐stranded RNA (dsRNA), the active component of a viral infection, in inducing the expression of inducible nitric oxide synthase (iNOS) in human astroglia. DsRNA in the form of synthetic polyinosinic‐polycytidylic acid (poly IC) induced expression of iNOS and iNOS promoter‐driven luciferase activity through activation of nuclear factor (NF)‐κB and CCAAT/enhancer‐binding proteinβ (C/EBPβ). In addition, we show that inhibitors of protein kinase R attenuated iNOS by suppressing the activation of NF‐κB but not C/EBPβ. In contrast, knock down of p38 mitogen‐activated protein kinase (MAPK) attenuated iNOS by suppressing the activation of C/EBPβ but not NF‐κB. This study delineates a novel role of dsRNA in inducing the expression of iNOS through dsRNA‐activated protein kinase (PKR)‐mediated activation of NF‐κB and p38‐mediated activation of C/EBPβ in human astroglia that may participate in virus‐induced neurological abnormalities.
Nur77 induction and activation are necessary for interleukin‐1 stimulation of proopiomelanocortin in AtT‐20 corticotrophs
Authors: Kovalovsky Damian , Paez Pereda Marcelo , Labeur Marta , Renner Ulrich , Holsboer Florian , Stalla Günter K , Arzt Eduardo
Published: March 2004

Nur77 and Nurr1 are critical for proopiomelanocortin (POMC) regulation by corticotrophin releasing hormone (CRH) in corticotrophs. We analyze the regulation and activity of Nur77 by interleukin (IL)‐1 in AtT‐20 corticotrophic cells and its consequences on POMC regulation. IL‐1 induces Nur77 and not Nurr1 mRNA and shows an increased transcriptional activity on the NurRE site, an effect dependent of p38 protein kinase activity. A NurRE mutation abrogates POMC promoter transcription by IL‐1 and a stable AtT‐20 clone overexpressing a dominant negative form of Nur77 is unresponsive to IL‐1‐dependent POMC induction and adrenocorticotrophin (ACTH) secretion. These results demonstrate that Nur77 is essential for POMC stimulation by IL‐1 in corticotrophs.
The Role of Polymerase Chain Reaction and Its Newer Developments in Feline Medicine
Authors: Lutz H , Leutenegger C , Hofmann-Lehmann R
Published: March 2004

We give a brief overview on the principles of the polymerase chain reaction (PCR), reverse transcriptase PCR (RT-PCR), quantitative competitive PCR and real-time PCR (TaqMan technology). The literature dealing with PCR and its role in the diagnosis, pathogenesis and research of infectious diseases of the domestic cat is reviewed. Cross-contaminations which occasionally occur during handling of amplified DNA may be an important problem in the PCR laboratory. In many infectious diseases, PCR results are difficult to interpret as their predictive positive and negative values are not always known. Newer assays, such as TaqMan procedures, are becoming increasingly reliable and cost-effective. It can be expected that additional knowledge on how to interpret PCR results will soon be available.
Society of the Counter-Spectacle: Debord and the Theatre of the Situationists
Authors: PUCHNER MARTIN
Published: March 2004

This article examines the work of the Situationists and their leading member, Guy Debord, as it relates to theatre history and the history of the manifesto. The Situationists privileged the writing of manifestos over the production of art works in order to avoid the fate of the historical avant-garde, whose provocative art had been co-opted by the cultural establishment. Despite this pro-manifesto and anti-art stance, the Situationists drew on the theatre, envisioning the construction of theatrical ‘situations’ influenced by the emerging New York happening as well as modern theatre artists such as Brecht and Artaud. This theatrical inheritance prompted a recent theatrical representation of their activities based on Greil Marcus's Lipstick Traces. What this theatrical rendering demonstrated, however, is that the theatricality of the ‘situation’ is different from that produced on a stage, reminding us that the strategies of the neo-avant-garde cannot be easily transferred to a traditional theatrical form.
Animal Labour in the Theatrical Economy
Authors: RIDOUT NICHOLAS
Published: March 2004

In this article Nicholas Ridout argues that the work of the animal in theatrical performance generates an affective response which has both cognitive and potential value. Using examples of the appearance of animals on stage in recent work by Socìetas Raffaello Sanzio and Jan Fabre, it suggests that when animals are coerced into the making of meaning in theatre, the unease which their appearance provokes is not so much the result of an encounter with the irreducibly ‘other’ as a recognition of familiarity, proximity and a history of exploitation. That animals can readily be seen to be exploited on stage allows the possibility of the exploitation of humans being seen as part of the same economy and this same history.
Spurious weather radar echo identification and removal using multisource temperature information
Authors: Michelson Daniel B. , Sunhede Daniel
Published: March 2004

A simple and pragmatic method utilising the difference between analysed near‐surface and Meteosat IR temperatures (ΔT) is presented and applied with the aim of identifying and removing non‐precipitation echoes in weather radar composite imagery. Despite inherent deficiencies in these multisource data, such as lower spatial and temporal resolutions relative to the radar data, T is demonstrated to efficiently identify efficiently those areas void of potentially precipitating clouds, and to remove radar echoes in them. A set of 243 manually analysed composites from the summer of 2000 was used to evaluate the method. False alarm rates (FAR), percent correct (PC) and Hanssen‐Kuipers skill (HKS) scores were calculated from standard contingency tables for five echo classes: weak, strong, land, sea, and all. FAR was lowered in all classes, PC was generally raised by a few percent to be over 95%, while HKS either remained unchanged or was slightly lowered through the application of T. These results indicate that T successfully removes a significant amount of non‐precipitation, sometimes at the expense of a small amount of true precipitation. This penalty is larger over sea, which indicates that the method may need to be tuned differently for land and sea environments. This method may act as a foundation on which improvements to radar data quality control can be made with the introduction of new and improved satellite instrumentation such as that found on board the Meteosat Second Generation platform. However, this type of method should remain complementary to improved signal processing and radar data analysis techniques. Copyright © 2004 Royal Meteorological Society.
The accuracy of downward short‐ and long‐wave radiation at the earth's surface calculated using simple models
Authors: Finch J. W. , Best M. J.
Published: March 2004

Estimates of the downward global solar and long‐wave radiations are commonly made using simple models. We have tested the estimates produced by a number of these simple models against the values predicted by the radiative transfer model used in a climate model in order to determine their suitability for global applications. For clear sky, two simple models were comparable, but under cloudy conditions a combination of a clear‐sky model based on the Angstrom‐Prescott equation (which deals with the downwelling solar radiation) with a cloud transmissivity utilising total cloud fraction proved best. The lowest root mean square errors were 27 W m−2 for clear‐sky global solar radiation and 90 W m−2 for cloudy conditions. For downward long‐wave radiation in clear‐sky conditions, the model of Garratt (1992) performed best with a root mean square error of 24 W m−2. However, in cloudy conditions the model of Idso & Jackson (1969) performed best with a root mean square error of 22 W m−2, and, as it performs nearly as well as that of Garratt (1992) in clear‐sky conditions, it is probably the best choice. Copyright © 2004 Royal Meteorological Society.
Re‐Os isotope systematics in carbonates from Serpent Mound, Ohio: Implications for Re‐Os dating of crustal rocks and the osmium isotopic composition of Ordovician seawater
Authors: Widom Elisabeth , Gaddis Sarah J. , Wells Norman E.
Published: March 2004

Eleven core samples of Ordovician carbonates and shale from within and nearby the Serpent Mound (Ohio) cryptoexplosion structure were analyzed for Re‐Os isotopes. Whole‐rock samples span a large range in measured 187Os/188Os (0.714 to 6.083), and exhibit a linear correlation of 187Os/188Os with 187Re/188Os. The linear relationship is inconsistent with a meteorite‐crust mixing trend, but could represent an errorchron with an age of 485 ± 35 Ma, and an initial 187Os/188Os of 0.54 ± 0.15. In order to assess whether the errorchron slope and initial 187Os/188Os ratio may provide constraints on depositional age and the 187Os/188Os ratio of Ordovician seawater, acetic acid and HCl leaching studies were done on selected samples. The 87Sr/86Sr ratios of the leachates vary from 0.7081 to 0.7091, within the range found in Middle‐Upper Ordovician brachiopods [Shields et al., 2003], and consistent with the leachable fraction of the carbonates representing Ordovician seawater compositions. 187Os/188Os signatures for the leached samples are generally lower than those of respective whole rocks. However, five of six leachate samples produce a strong linear correlation on a Re‐Os isochron diagram, the slope of which reflects an “age” of 443 ± 34 Ma, consistent with biostratigraphic constraints on the depositional ages of the sampled rock units (∼445–472 Ma). The calculated initial 187Os/188Os of 0.53 ± 0.04 is distinctly lower than present‐day seawater, and, if representative of Ordovician seawater, may reflect relatively low continental weathering rates due to waning Pan African orogenies as proposed to explain the slow decrease in seawater 87Sr/86Sr starting in early Ordovician [Qing et al., 1998].
A 1200 year record of hydrologic variability in the Sierra Nevada from sediments in Walker Lake, Nevada
Authors: Yuan Fasong , Linsley Braddock K. , Lund Steve P. , McGeehin John P.
Published: March 2004

Measurements of the oxygen isotopic composition (δ18O) of the total inorganic carbon (TIC) fraction from cored sediments of Walker Lake, Nevada, were conducted at an average resolution of ∼3 years per sample over the last 1200 years. On the basis of radiocarbon analysis on the total organic carbon (TOC) fraction, a δ18O time series was created to reconstruct changes in hydrologic conditions back to AD 800. The timings of variations in the TIC δ18O record are generally consistent with the tree ring‐based Sacramento River flow record spanning AD 869 to 1977, indicating that Walker Lake δ18O contains information about past changes in at least regional hydrologic conditions. Comparison with the δ18O record from Pyramid Lake sediments indicates that both basins have recorded five century‐scale oscillations in regional hydrologic conditions since AD 800. Several of these changes in hydrologic conditions appear synchronous with century‐scale California Current water temperature changes derived from analysis of sediment cores from the Santa Barbara Basin also attesting to the regional extent of these climatic fluctuations. Nearly synchronous oscillations in the Sierra wetness and the California Current suggest that regional changes in atmospheric circulation may have played an important role in century‐scale climate variability over the last millennium.
Evidence for eastward mantle flow beneath the Caribbean plate from neotectonic modeling
Authors: Negredo Ana M. , Jiménez‐Munt Ivone , Villaseñor Antonio
Published: March 2004

We have applied a thin‐shell modeling technique to study the neotectonics of the Caribbean plate. Kinematic conditions computed assuming rotation poles and velocities from NUVEL‐1A and from recent geodetic studies have been applied at the lateral boundaries of the model to represent the motion of the adjacent plates with respect to the Caribbean. We have generated a large number of models varying the values of the fault friction coefficient and shear traction on the base of the plate exerted by mantle flow. The quality of the models has been evaluated by comparing their predictions with data on seismic strain rate, stress direction, geodetic baseline changes, and slip rates. Our results indicate that the only successful models are those with low values of fault friction coefficient and significant basal shear traction exerted by eastward mantle flow beneath the Caribbean.
A potential bias in coral reconstruction of sea surface temperature
Authors: Solow Andrew R. , Huppert Amit
Published: March 2004

Isotopic measurements in corals are used to reconstruct past sea surface temperature. These reconstructions are based on calibration regression analyses using paired measurements of modern isotopic composition and sea surface temperature. It is shown that error in these measurements of sea surface temperature can lead to substantial bias in reconstruction. Provided the variance of the measurement error is known or can be estimated, a simple correction can eliminate this bias.
Petrogenetic grid in the system MgO‐SiO2‐H2O up to 30 GPa, 1600°C: Applications to hydrous peridotite subducting into the Earth’s deep interior
Authors: Komabayashi Tetsuya , Omori Soichi , Maruyama Shigenori
Published: March 2004

A semiquantitative petrogenetic grid in the system MgO‐SiO2‐H2O up to 30 GPa and 1600°C was constructed using Schreinemakers analysis on previous experimental data. The grid includes stability relations of hydrous wadsleyite, hydrous ringwoodite, and dense hydrous magnesium silicates (DHMSs): phase A, phase D, phase E, and superhydrous phase B. A sequence of chemical reactions among these hydrous phases was clarified. In the mantle transition zone (410–660‐km depth), hydrous wadsleyite and hydrous ringwoodite are stable even at a standard mantle temperature of 1600°C, whereas in the other depths, nominal hydrous phases including DHMSs are stable below 1400°C. Newly found phase transitions in hydrous wadsleyite and hydrous ringwoodite are multiphase and multireaction because their compositions are on neither MgO‐SiO2 nor Mg2SiO4‐H2O tie lines, different from single transition in the dry Mg2SiO4 system. The grid indicates that water in the subducting slab peridotite would be transported to the bottom of the upper mantle by several DHMSs and hydrous polymorphs of olivine, via solid‐solid reactions after antigorite decomposition. Finally, DHMSs would dehydrate to liberate free water at the upper mantle‐lower mantle boundary layer or deeper level. We also examined a relation between the predicted depth distributions of dehydration reactions in slab peridotite along several possible pressure‐temperature paths and the mode of seismic frequency in each subduction zone. The result suggests a possible origin of intermediate to deep seismicity by the dehydration of hydrous phases in the subducting slab.
Secular sea level change in the Russian sector of the Arctic Ocean
Authors: Proshutinsky A. , Ashik I. M. , Dvorkin E. N. , Häkkinen S. , Krishfield R. A. , Peltier W. R.
Published: March 2004

Sea level is a natural integral indicator of climate variability. It reflects changes in practically all dynamic and thermodynamic processes of terrestrial, oceanic, atmospheric, and cryospheric origin. The use of estimates of sea level rise as an indicator of climate change therefore incurs the difficulty that the inferred sea level change is the net result of many individual effects of environmental forcing. Since some of these effects may offset others, the cause of the sea level response to climate change remains somewhat uncertain. This paper is focused on an attempt to provide first‐order answers to two questions, namely, what is the rate of sea level change in the Arctic Ocean, and furthermore, what is the role of each of the individual contributing factors to observed Arctic Ocean sea level change? In seeking answers to these questions we have discovered that during the period 1954–1989 the observed sea level over the Russian sector of the Arctic Ocean is rising at a rate of approximately 0.123 cm yr−1 and that after correction for the process of glacial isostatic adjustment this rate is approximately 0.185 cm yr−1. There are two major causes of this rise. The first is associated with the steric effect of ocean expansion. This effect is responsible for a contribution of approximately 0.064 cm yr−1 to the total rate of rise (35%). The second most important factor is related to the ongoing decrease of sea level atmospheric pressure over the Arctic Ocean, which contributes 0.056 cm yr−1, or approximately 30% of the net positive sea level trend. A third contribution to the sea level increase involves wind action and the increase of cyclonic winds over the Arctic Ocean, which leads to sea level rise at a rate of 0.018 cm yr−1 or approximately 10% of the total. The combined effect of the sea level rise due to an increase of river runoff and the sea level fall due to a negative trend in precipitation minus evaporation over the ocean is close to 0. For the Russian sector of the Arctic Ocean it therefore appears that approximately 25% of the trend of 0.185 cm yr−1, a contribution of 0.048 cm yr−1, may be due to the effect of increasing Arctic Ocean mass.
Electron attachment to gas-phase uracil
Authors: Denifl S. , Ptasińska S. , Hanel G. , Gstir B. , Probst M. , Scheier P. , Märk T. D.
Published: March 2004

We present results about dissociative electron attachment (DEA) to gas-phase uracil (U) for incident electron energies between 0 and 14 eV using a crossed electron/molecule beam apparatus. The most abundant negative ion formed via DEA is (U-H)−, where the resonance with the highest intensity appears at 1.01 eV. The anion yield of (U-H)− shows a number of peaks, which can be explained in part as being due to the formation of different (U-H)− isomers. Our results are compared with high level ab initio calculations using the G2MP2 method. There was no measurable amount of a parent ion U−. We also report the occurrence of 12 other fragments produced by dissociative electron attachment to uracil but with lower cross sections than (U-H)−. In addition we observed a parasitic contaminating process for conditions where uracil was introduced simultaneously with calibrant gases SF6 and CCl4 that leads to a sharp peak in the (U-H)− cross section close to 0 eV. For (U-H)− and all other fragments we determined rough measures for the absolute partial cross section yielding in the case of (U-H)− a peak value of σ (at 1.01 eV)=3×10−20 m2.
Infrared spectroscopy of acetone–water liquid mixtures. II. Molecular model
Authors: Max Jean-Joseph , Chapados Camille
Published: March 2004

In aqueous acetone solutions, the strong bathochromic shifts observed on the OH and CO stretch infrared (IR) bands are due to hydrogen bonds between these groups. These shifts were evaluated by factor analysis (FA) that separated the band components from which five water and five acetone principal factors were retrieved [J. Chem. Phys. 119, 5632 (2003)]. However, these factors were abstract making them difficult to interpret. To render them real an organization model of molecules is here developed whose abundances are compared to the experimental ones. The model considers that the molecules are randomly organized limited by the hydrogen bond network formed between the water hydrogen atoms and the acetone or water oxygen atoms, indifferently. Because the oxygen of water has two covalent hydrogen atoms which are hydrogen-bonded and may receive up to two hydrogen atoms from neighbor molecules hydrogen-bonded to it, three types of water molecules are found: OH2, OH3, and OH4 (covalent and hydrogen bonds). In the OH stretch region these molecules generate three absorption regimes composed of ν3, ν1, and their satellites. The strength of the H-bond given increases with the number of H-bonds accepted by the oxygen atom of the water H-bond donor, producing nine water situations. Since FA cannot separate those species that evolve concomitantly the nine water situations are regrouped into five factors, the abundance of which compared exactly to that retrieved by FA. From the factors’ real spectra the OH stretch absorption are simulated to, respectively, give for the ν3 and ν1 components the mean values for OH2, 3608, 3508; OH3, 3473, 3282 and OH4, 3391, 3223 cm−1. The mean separations from the gas-phase position which are respectively about 150, 330, and 400 cm−1 are related to the vacancy of the oxygen electron doublets: two, one, and zero, respectively. No acetone hydrate that sequesters water molecules is formed. Similarly, acetone produces ten species, two of which evolve concomitantly. Spectral similarities further reduce these to five principal IR factors, the abundance of which compared adequately to the experimental results obtained from FA. The band assignment of the five-acetone spectra is given.
A local second-order Møller–Plesset method with localized orbitals: A parallelized efficient electron correlation method
Authors: Nakao Yoshihide , Hirao Kimihiko
Published: March 2004

Using orthogonal localized occupied orbitals we have developed and implemented a parallelized local second-order Møller–Plesset (MP2) method based on the idea developed by Head-Gordon and co-workers. A subset of nonorthogonal correlation functions (the orbital domain) was assigned to each of the localized occupied orbitals using a distance criterion and excitations from localized occupied orbitals that were arranged into subsets. The correlation energy was estimated using a partial diagonalization and an iterative efficient method for solving large-scale linear equations. Some illustrative calculations are provided for molecules with up to 1484 Cartesian basis sets. The orbital domain sizes were found to be independent of the molecular size, and the present local MP2 method covered about 98%–99% of the correlation energy of the conventional canonical MP2 method.
Density functional theory investigation of benzenethiol adsorption on Au(111)
Authors: Nara Jun , Higai Shin’ichi , Morikawa Yoshitada , Ohno Takahisa
Published: March 2004

We have studied the adsorption of benzenethiol molecules on the Au(111) surface by using first principles total energy calculations. A single thiolate molecule is adsorbed at the bridge site slightly shifted toward the fcc-hollow site, and is tilted by 61° from the surface normal. As for the self-assembled monolayer (SAM) structures, the (2∛×∛)R30° herringbone structure is stabilized against the (∛×∛)R30° structure by large steric relaxation. In the most stable (2∛×∛)R30° SAM structure, the molecule is adsorbed at the bridge site with the tilting angle of 21°, which is much smaller compared with the single molecule adsorption. The van der Waals interaction plays an important role in forming the SAM structure. The adsorption of benzenethiolates induces the repulsive interaction between surface Au atoms, which facilitates the formation of surface Au vacancy.
Sub-Doppler rotationally resolved spectroscopy of lower vibronic bands of benzene with Zeeman effects
Authors: Doi Atsushi , Kasahara Shunji , Katô Hajime , Baba Masaaki
Published: March 2004

Sub-Doppler high-resolution excitation spectra and the Zeeman effects of the 601, 101601, and 102601 bands of the S1 1B2u←S0 1A1g transition of benzene were measured by crossing laser beam perpendicular to a collimated molecular beam. 1593 rotational lines of the 101601 band and 928 lines of the 102601 band were assigned, and the molecular constants of the excited states were determined. Energy shifts were observed for the S1 1B2u(v1=1,v6=1,J,Kl=−11) levels, and those were identified as originating from a perpendicular Coriolis interaction. Many energy shifts were observed for the S1 1B2u(v1=2,v6=1,J,Kl) levels. The Zeeman splitting of a given J level was observed to increase with K and reach the maximum at K=J, which demonstrates that the magnetic moment lies perpendicular to the molecular plane. The Zeeman splittings of the K=J levels were observed to increase linearly with J. From the analysis, the magnetic moment is shown to be originating mostly from mixing of the S1 1B2u and S2 1B1u states by the J–L coupling (electronic Coriolis interaction). The number of perturbations was observed to increase as the excess energy increases, and all the perturbing levels were found to be a singlet state from the Zeeman spectra.