bluuebunny/crossref_metadata_2025 huggingface dataset:
New Modes of Governance in the Spanish Electricity and Gas Sectors
Authors: MORAL SORIANO LEONOR
Published: November 2007

This paper analyses the institutional framework of the Spanish electricity and gas markets from their emergence at the beginning of the twentieth century until the liberalisation process encouraged by the European Union. European processes of liberalisation involving the introduction of regulation and competition and the application of non-hierarchical modes have raised the number of both public and private actors taking part in sectoral governance. However, none of these modes is new for the sector. A historical perspective shows the conditions under which the threat of governmental intervention and the discretion granted to sectoral governance differed significantly between sectors. While the threat to nationalise and monopolise the electricity sector contributed to the creation of a private agent and a model of self-regulation with a large measure of discretion, in the gas sector the public presence was strong and control tight. Thus, the paper concludes that one should not presuppose that old modes of governance are strongly governmental and hierarchical. The opposite proves to be the case in the Spanish electricity sector, where new modes of governance are now more linked to hierarchy.
On Government, Governance and Judicial Review: The Case of European Competition Policy
Authors: LEHMKUHL DIRK
Published: November 2007

From a traditional rationalist principal-agent framework, the development of the European Community’s competition policy could appear as a straightforward story of agency loss. However, the recent overhaul of competition policy, which the Community presented in terms of decentralisation, appears to have changed the story. We are confronted with the uncommon event of an agent (the European Commission) returning some of its powers to the principals (the member states). This paper resolves the puzzle by highlighting the role of the Commission and of European courts. It has become part of the Commission’s strategy to pursue its objectives through legally non-binding instruments such as notices or guidelines or co-operation in networks. These instruments do not need the approval of the Council of Ministers or the European Parliament. With the Commission’s promotion of new modes of governance, the link between sectoral governance (in terms of regulation specific to competition policy) and the governmental shadow of hierarchy shifted to an increasing extent to judicial review by European courts. Alongside this shift, the character of judicial review has changed in the direction of judicial control, as European courts no longer restrict themselves to review of the legality of Commission actions, but also engage in assessing the facts themselves.
A NEW SPECIES OF NECKERA (NECKERACEAE, BRYOPSIDA) FROM XIZANG, CHINA
Authors: Enroth J. , Ji M.
Published: November 2007

A new species of Neckeraceae, Neckera serrulatifolia Enroth & M.Ji, is described from Xizang (Tibet), China. It belongs in an Asian group of relatively robust, distinctly stipitate species with an obtuse leaf apex, relatively long costa and strongly incrassate-porose leaf cell walls, but differs from the other species by the combination of strongly complanate and undulate branch leaves, long leaf decurrencies, and serrulate margins at leaf base and at midleaf. The sporophytes remain unknown.
A REVISION OF AESCHYNANTHUS (GESNERIACEAE) IN THAILAND
Authors: Middleton D. J.
Published: November 2007

The species of Aeschynanthus Jack (Gesneriaceae) in Thailand are revised. Twenty species are recognized, a key to the species is given, all names are typified, and detailed descriptions of all species are provided. Conservation assessments are given for all species. Aeschynanthus minutifolius D.J.Middleton is newly described. Micraeschynanthus Ridl. is reduced to synonymy and a new combination is given for its only species: Aeschynanthus dischidioides (Ridl.) D.J.Middleton.
Woody Plants of Western African Forests. W. D. Hawthorne & C. C. H. Jongkind, illustrated by R. Wise & M. Spitteler.
Authors: Harris D. J.
Published: November 2007

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Diagnose: Irrwege und Abkürzungen
Authors: Steurer  , Bachmann
Published: November 2007

Diagnose ist eine Form von Wissen, es ist das Wissen über die Wahrscheinlichkeit des Vorliegens einer Erkrankung bei einem bestimmten Patienten. Die wichtigsten Schritte im diagnostischen Prozess sind das Sammeln von Informationen (Anamnese und klinische Untersuchung), die Bündelung von Informationen, die mentale Repräsentation des klinischen Problems und dann die Aktivierung so genannter Skripte im Gehirn des Arztes. Daraus entwickelt sich eine Liste möglicher Diagnosen, deren Liste durch weitere Informationen, meist Laboruntersuchungen oder die Resultate bildgebender Verfahren auf die wahrscheinlichste Diagnose reduziert wird. Am häufigsten passieren diagnostische Fehler beim Sammeln der Informationen (zu wenig oder zuviel Informationen) und bei der Interpretation der Informationen.
Global budget of molecular hydrogen and its deuterium content: Constraints from ground station, cruise, and aircraft observations
Authors: Price Heather , Jaeglé Lyatt , Rice Andrew , Quay Paul , Novelli Paul C. , Gammon Richard
Published: November 2007

The distribution and atmospheric budgets for molecular hydrogen and its deuterium component δD are simulated with the GEOS‐Chem global chemical transport model and constrained by observations of H2 from the NOAA Climate Monitoring and Diagnostics Laboratory network and δD observations from ship and ground stations. Our simulation includes a primary H2 source of 38.8 Tg a−1 (22.7 Tg a−1 from fossil and biofuels, 10.1 Tg a−1 from biomass burning, 6.0 Tg a−1 from the ocean) (where a is years) and a secondary photochemical source from photolysis of formaldehyde of 34.3 Tg a−1. The simulated global tropospheric mean H2 is 525 ppbv, with a tropospheric burden of 141 Tg and tropospheric lifetime of 1.9 a. Uptake by enzymes in soils accounts for 75% of the H2 sink, with the remainder due to reaction with OH. The model captures the observed latitudinal, vertical, and seasonal variations of H2. For δD we find that a photochemical source signature from methane and biogenic volatile organic compound oxidation of 162‰ yields a global mean atmospheric δD of 130‰, consistent with atmospheric observations. The model captures the observed latitudinal gradient in δD, simulating a 21‰ greater enrichment in the Southern Hemisphere because of the predominance of isotopically depleted fossil fuel emissions in the Northern Hemisphere. We find that stratospheric‐tropospheric exchange results in 37‰ enrichment of tropospheric δD. Our simulation provides new simultaneous constraints on the H2 soil sink (55 ± 8 Tg a−1), the ocean source (6 ± 3 Tg a−1), and the isotopic signature for photochemical production (162 ± 57‰).
Analysis of seasonal terrestrial water storage variations in regional climate simulations over Europe
Authors: Hirschi Martin , Seneviratne Sonia I. , Hagemann Stefan , Schär Christoph
Published: November 2007

Land‐surface processes play a major role in the climate system, and their validation is crucial to improve current climate models. Here we investigate the seasonal evolution of terrestrial water storage (TWS) (includes all water stored on land) in an ensemble of 30‐year‐long climate simulations from the PRUDENCE archive (9 regional and 2 global models), representing current and future climatic conditions. For validation purposes we employ a recently published basin‐scale water‐balance (BSWB) data set of diagnosed monthly TWS variations, where the term variations refers to monthly changes in TWS. The analysis is conducted in five large‐scale European domains composed of major river basins. This analysis shows that the climatology of most models lies within the interannual variability of the BSWB data set in the investigated regions, but the different models sometimes display considerable discrepancies in the seasonal evolution of TWS. In particular, we find that all models suffer from a considerable underestimation of interannual TWS variability. The deviations of the individual models from the BSWB data set can be linked to biases in the hydrological fluxes (i.e., precipitation, runoff, evapotranspiration). The simulated future changes for the Intergovernmental Panel on Climate Change (IPCC) A2 scenario suggest an enhancement of the seasonal cycle of TWS, with drier soils in summer. Mainly in the Central European domain, several models show a reduction of the year‐to‐year variability of summer TWS variations, indicating an exhaustion of the models' soil water reservoirs by the end of summer under future climatic conditions.
Deflecting dams and the formation of oblique shocks in snow avalanches at Flateyri, Iceland
Authors: Cui X. , Gray J. M. N. T. , Jóhannesson T.
Published: November 2007

Snow avalanches are a threat in many populated mountainous regions, and deflecting dams are often built to divert them away from people, and infrastructure, into less harmful areas. When an avalanche is deflected by a dam or wedge, it often generates rapid changes in the flow thickness and velocity, which can be modeled as an oblique shock wave. This paper reviews classical oblique shock theory, which was originally developed for shallow water flows, and uses it to make predictions of the maximum runup height on a deflecting dam, the downstream flow velocity, and the width of the channelized stream. The theory is used to investigate field observations of snow avalanches at Flateyri in Iceland, where a dam has deflected two avalanches away from the town and produced a channelized stream that flowed parallel to the dam. The results indicate that there is no one single set of upstream flow conditions that parameterizes the flow behavior, but the solution evolves as the avalanche propagates along the dam in response to the deceleration imposed by the slope. Fully time‐dependent shock capturing numerical simulations of the Skollahvilft avalanche, which hit the dam on 21 February 1999, are used to show how the channelized stream widens as the avalanche slows down and thickens toward the end of the runout zone. The oblique shock relations nevertheless provide useful local order of magnitude estimates for the flow conditions immediately upstream of the shock.
Rainfall rate modeling and worst month statistics for millimetric line‐of‐sight radio links in South Africa
Authors: Owolawi Pius A. , Afullo Thomas J.
Published: November 2007

Rain attenuation has a serious impact on the availability and performance of radio communication services operating in the frequencies above 10 GHz. In order to reliably predict rain attenuation for a given location, there is a need for studying monthly and seasonal rainfall variability, worst month and average worst month statistics of rain, and rainfall rate distribution models for the site under study. In this paper, the tasks are tackled by processing 5‐year (a) rain rate data for selected sites in South Africa. The dependence of the percentage of the average year (AY) on percentage of time of the average worst month (AWM) of rainfall rate and the obtained rainfall rate distribution models for eight regions in South Africa are assessed by examining the root‐mean‐square (RMS), the average probability ratio (APR), and chi‐square statistic (CHI) on the basis of measured data and the International Telecommunication Union recommendation (ITU‐R) estimations.
X‐ray synchrotron diffraction study of natural gas hydrates from African margin
Authors: Bourry Christophe , Charlou Jean‐Luc , Donval Jean‐Pierre , Brunelli Michela , Focsa Cristian , Chazallon Bertrand
Published: November 2007

Natural gas hydrates recovered from the Congo‐Angola basin and Nigerian margins are analyzed by synchrotron X‐ray powder diffraction. Biogenic methane is the most abundant gas trapped in the samples and others minor components (CO2, H2S) are co‐clathrated in a type I cubic lattice structure. The refinement for the type I structure gives lattice parameters of a = 11.8646 (39) Å and a = 11.8619 (23) Å for specimens from Congo‐Angola and Nigerian margins respectively at 90 K. These values, intermediate between the lattice constant of less pure methane specimens and pure artificial methane hydrates, indicate that lattice constants can be affected by the presence of encaged CO2, H2S and other gas molecules, even in small amounts. Thermal expansion is also presented for Congo‐Angola hydrate in the temperature range 90–200 K. The coefficients are comparable with values reported for synthetic hydrates at low temperature and tend to approach thermal expansion of ice at higher temperature.
Daytime OIO in the Gulf of Maine
Authors: Stutz J. , Pikelnaya O. , Hurlock S. C. , Trick S. , Pechtl S. , von Glasow R.
Published: November 2007

The potential importance of iodine for marine boundary layer (MBL) chemistry has found increasing recognition in recent years. However, observations of the key iodine species are sparse and the chemical reactions of the iodine oxides are not well understood. Here we present Differential Optical Absorption Spectroscopy observations of IO, OIO in the MBL of the Gulf of Maine, U.S., during Summer 2004. We report the first daytime observation of OIO, indicating that this compound is rather photostable. Mixing ratios of IO were similar to, and those of OIO higher than, values reported for European coastal sites. Calculations with the one‐dimensional model MISTRA show that the observed simultaneous presence of elevated OIO and NOx cannot be explained by currently known iodine chemistry. Our results lead to the conclusion that thus far unknown chemical reactions of iodine oxides, probably involving iodine nitrates, might occur in the MBL.
Transformation of the Labrador Sea Water in the subpolar North Atlantic
Authors: Yashayaev Igor , van Aken Hendrik M. , Holliday N. Penny , Bersch Manfred
Published: November 2007

Development, spreading and decay of the thermohaline properties of two Labrador Sea Water (LSW) classes are described. During the development phase, a specific LSW class repeatedly mixed by winter convection in the Labrador Sea becomes colder, denser, thicker and deeper. Once convection weakens, the LSW class becomes isolated from the upper layer and starts to decay, rapidly losing its volume while retaining the same density due to isopycnal mixing with the neighbouring warm saline intermediate waters. A similar pattern in temperature, salinity and density is seen in the other basins with different time lags from about two years in the Irminger Sea to ten years in the northern Iceland Basin and Rockall Trough regions. The influence of LSW on the thermohaline properties of other North Atlantic water masses is also discussed.
Empirical transfer functions: Application to determination of outermost core velocity structure using SmKS phases
Authors: Alexandrakis Catherine , Eaton David W.
Published: November 2007

SmKS waves provide good resolution of outer‐core velocity structure, but are affected by heterogeneity in the D″ region. We have developed an Empirical Transfer Function (ETF) technique that transforms a reference pulse (here, SmKS) into a target waveform (SKKS) by: (1) time‐windowing the respective pulses, (2) applying Wiener deconvolution, and (3) convolving the output with a Gaussian waveform. Common source and path effects are implicitly removed by this process. We combine ETFs from 446 broadband seismograms to produce a global stack, from which S3KS‐SKKS differential time can be measured accurately. As a result of stacking, the scatter in our measurements (0.43 s) is much less than the 1.29 s scatter in previous compilations. Although our data do not uniquely constrain outermost core velocities, we show that the fit of most standard models can be improved by perturbing the outermost core velocity. Our best‐fitting model is formed using IASP91 with PREM‐like velocity at the top of the core.
Effect of earthworms on the community structure of active methanotrophic bacteria in a landfill cover soil
Authors: Héry Marina , Singer Andrew C , Kumaresan Deepak , Bodrossy Levente , Stralis-Pavese Nancy , Prosser Jim I , Thompson Ian P , Murrell J Colin
Published: November 2007

In the United Kingdom, landfills are the primary anthropogenic source of methane emissions. Methanotrophic bacteria present in landfill biocovers can significantly reduce methane emissions via their capacity to oxidize up to 100% of the methane produced. Several biotic and abiotic parameters regulate methane oxidation in soil, such as oxygen, moisture, methane concentration and temperature. Earthworm-mediated bioturbation has been linked to an increase in methanotrophy in a landfill biocover soil (AC Singer et al., unpublished), but the mechanism of this trophic interaction remains unclear. The aims of this study were to determine the composition of the active methanotroph community and to investigate the interactions between earthworms and bacteria in this landfill biocover soil where the methane oxidation activity was significantly increased by the earthworms. Soil microcosms were incubated with 13C-CH4 and with or without earthworms. DNA and RNA were extracted to characterize the soil bacterial communities, with a particular emphasis on methanotroph populations, using phylogenetic (16S ribosomal RNA) and functional methane monooxygenase (pmoA and mmoX) gene probes, coupled with denaturing gradient-gel electrophoresis, clone libraries and pmoA microarray analyses. Stable isotope probing (SIP) using 13C-CH4 substrate allowed us to link microbial function with identity of bacteria via selective recovery of ‘heavy’ 13C-labelled DNA or RNA and to assess the effect of earthworms on the active methanotroph populations. Both types I and II methanotrophs actively oxidized methane in the landfill soil studied. Results suggested that the earthworm-mediated increase in methane oxidation rate in the landfill soil was more likely to be due to the stimulation of bacterial growth or activity than to substantial shifts in the methanotroph community structure. A Bacteroidetes-related bacterium was identified only in the active bacterial community of earthworm-incubated soil but its capacity to actually oxidize methane has to be proven.
Prediction of glass-forming ability of metallic liquids
Authors: Bian Xiufang , Guo Jing , Lv Xiaoqian , Qin Xubo , Wang Caidong
Published: November 2007

We propose a concept for the prediction of the glass-forming ability (GFA) before quenching through studies of the stabilization of clusters in metallic liquids in terms of a parameter, B=dr∕dT (r is the correlation radius of clusters and T is the absolute temperature). Strong correlation between B and GFA was found for a broad range of alloy systems. When the absolute value of B is lower than 1×10−4nm∕K, the metallic liquid can be prepared into a metallic glass. This criterion is important for studies of glass-forming abilities of metallic liquids in the future.
A first principles theory of nuclear magnetic resonance J-coupling in solid-state systems
Authors: Joyce Siân A. , Yates Jonathan R. , Pickard Chris J. , Mauri Francesco
Published: November 2007

A method to calculate NMR J-coupling constants from first principles in extended systems is presented. It is based on density functional theory and is formulated within a planewave-pseudopotential framework. The all-electron properties are recovered using the projector augmented wave approach. The method is validated by comparison with existing quantum chemical calculations of solution-state systems and with experimental data. The approach has also been applied to the silicophosphate, Si5O(PO4)6, giving P31–Si29-couplings which are in excellent agreement with experiment.
Solute rotational dynamics at the water liquid/vapor interface
Authors: Benjamin Ilan
Published: November 2007

The rotational dynamics of a number of diatomic molecules adsorbed at different locations at the interface between water and its own vapors are studied using classical molecular dynamics computer simulations. Both equilibrium orientational and energy correlations and nonequilibrium orientational and energy relaxation correlations are calculated. By varying the dipole moment of the molecule and its location, and by comparing the results with those in bulk water, the effects of dielectric and mechanical frictions on reorientation dynamics and on rotational energy relaxation can be studied. It is shown that for nonpolar and weekly polar solutes, the equilibrium orientational relaxation is much slower in the bulk than at the interface. As the solute becomes more polar, the rotation slows down and the surface and bulk dynamics become similar. The energy relaxation (both equilibrium and nonequilibrium) has the opposite trend with the solute dipole (larger dipoles relax faster), but here again the bulk and surface results converge as the solute dipole is increased. It is shown that these behaviors correlate with the peak value of the solvent-solute radial distribution function, which demonstrates the importance of the first hydration shell structure in determining the rotational dynamics and dependence of these dynamics on the solute dipole and location.
Gyrokinetic modeling: A multi-water-bag approach
Authors: Morel P. , Gravier E. , Besse N. , Klein R. , Ghizzo A. , Bertrand P. , Garbet X. , Ghendrih P. , Grandgirard V. , Sarazin Y.
Published: November 2007

Predicting turbulent transport in nearly collisionless fusion plasmas requires one to solve kinetic (or, more precisely, gyrokinetic) equations. In spite of considerable progress, several pending issues remain; although more accurate, the kinetic calculation of turbulent transport is much more demanding in computer resources than fluid simulations. An alternative approach is based on a water-bag representation of the distribution function that is not an approximation but rather a special class of initial conditions, allowing one to reduce the full kinetic Vlasov equation into a set of hydrodynamic equations while keeping its kinetic character. The main result for the water-bag model is a lower cost in the parallel velocity direction since no differential operator associated with some approximate numerical scheme has to be carried out on this variable v∥. Indeed, a small bag number is sufficient to correctly describe the ion temperature gradient instability.
An experimental and theoretical study of the S1←S transition of p-ethynyltoluene
Authors: Philis John G. , Melissas Vasilios S.
Published: November 2007

The one photon and the two photon S1←S0 spectra of jet-cooled p-ethynyltoluene have been measured for the first time, and a detailed vibronic analysis for both spectra has been attained. Mass analyzed resonance enhanced multiphoton ionization spectroscopy is the employed technique. In the one photon spectrum, the allowed component (origin and Franck-Condon bands) is much weaker than the forbidden component, and the same mechanisms as in the one photon spectrum of phenylacetylene are observed. The methyl torsional transitions are active. The 000 band is at 35483cm−1. The two photon spectrum is very strong and bears a resemblance to the two photon spectrum of phenylacetylene. The potential barrier of the methyl rotor in the S1 state has been determined as V6=−12cm−1 with BCH3=5.55cm−1. Ab initio calculations, MP2(full)/cc-pVTZ and CAS/cc-pVTZ, have been implemented for the geometry optimization and the normal mode vibration computation in the S0 and S1 states.
Automatic generation of potential energy and property surfaces of polyatomic molecules in normal coordinates
Authors: Toffoli D. , Kongsted J. , Christiansen O.
Published: November 2007

A procedure for the automatic construction of Born-Oppenheimer (BO) potential energy and molecular property surfaces in rectilinear normal coordinates is presented and its suitability and accuracy when combined with vibrational structure calculations are assessed. The procedure relies on a hierarchical n-mode representation of the BO potential energy or molecular property surface, where the n-mode term of the sequence of potentials/molecular properties includes only the couplings between n or less vibrational degrees of freedom. Each n-mode cut of the energy/molecular property surface is first evaluated in a grid of points with ab initio electronic structure methods. The ab initio data are then spline interpolated and a subsequent polynomial fitting provides an analytical semiglobal representation for use in vibrational structure programs. The implementation of the procedure is outlined and the accuracy of the method is tested on water and difluoromethane. Strategies for improving the proposed algorithm are also discussed.
Theoretical investigation of polarization scaling in ultrathin epitaxial PbZrxTi1−xO3 films
Authors: Qiu Q. Y. , Nagarajan V.
Published: November 2007

We present a theoretical analysis of the scaling of the polarization and the static dielectric susceptibility through a mean-polarization approach for ultrathin epitaxial PbZrxTi1−xO3 thin films. We use the traditional Euler-Lagrangian framework applied to a Landau-Ginzburg-Devonshire (LGD) nonlinear thermodynamic treatment. The novelty of our approach is that the model hinges on using experimentally measured correlation lengths and temperature scaling relationships to give the size-dependent expansion parameters of the nonlinear thermodynamic potential. These are then used in a Taylor series expansion of the polarization at the center of the film. We show that this method is able to correctly predict experimentally observed scaling without the need for the so-called extrapolation length (which is impossible to measure experimentally). Furthermore, as no implicit correlation between the correlation length (ξ) and the coefficient of the gradient term in the LGD potential (g11) is assumed, the model thus involves fully experimentally measurable parameters and their systematic temperature dependence rather than implicit assumptions. The model finds that the Curie temperature in ultrathin films is more sensitive to epitaxial strain as compared to the polarization and that the critical thickness is strongly dependent on the “temperature-epitaxial strain” parameter space. Interestingly, while it finds that at lower temperatures the depolarization field does play a strong role in the thickness dependence as well as spatial profile of the polarization, with increasing temperature, a significant weakening of the role of depolarization fields occurs. Consequently the interface-induced suppression is lower and, as a result, the polarization profile is more homogenous at higher temperatures. This indicates that systematic temperature dependent studies are fundamental to further understanding of size effects in ferroelectrics.
Low-frequency 1/f noise of RuO2-glass thick resistive films
Authors: Kolek A. , Stadler A. W. , Ptak P. , Zawiślak Z. , Mleczko K. , Szałański P. , Żak D.
Published: November 2007

Measurements of low-frequency noise in thick-film resistors at low temperatures are reported. Films were prepared in a standard “high temperature” process: 20 nm sized RuO2 powder was mixed with 0.5 μm granular lead–borosilicate glass and organic solvent to give a paste, which was then screen printed onto alumina substrates and fired in a tunnel furnace. Measurements below liquid helium temperature reveal that the low frequency (1/f) noise increases with decreasing temperature, approximately as T−α, α=2.1±0.1. Up to 4 T no dependence of noise intensity on magnetic field has been observed. Measurements of noise spectra in the range 4−300 K show that spectral and temperature slopes obey Dutta, Dimon, and Horn equation [Phys. Rev. Lett. 43, 646 (1979)] only in the range T>10 K. Below this temperature a gap of constant width opens between noise exponent calculated from the spectral slope and from temperature dependence of noise magnitude. This gap occurs due to the change of noise coupling mechanism that takes place at ≈10 K. At higher temperatures this coupling is temperature independent. At lower temperatures coupling becomes temperature dependent. It is shown that data agree quantitatively with the concept that noise sources modulate energies for thermally activated hops in the percolation network.
Solution of three-dimensional fiber orientation in two-dimensional fiber suspension flows
Authors: Zhou Kun , Lin Jianzhong , Chan Tat Leung
Published: November 2007

The orientation of fibers in simple two-dimensional flows is investigated. According to different ranges of the Péclet number, Pe, defined as the ratio of a characteristic rotational speed of fibers and the orientational diffusivity, three methods are developed: characteristic method for Pe=∞, regular perturbation method for Pe⪢1, and spectral method for everything else. All the methods subtly utilize the evolving solution of the rotational dynamics of fibers, which is also given in this paper. Especially, the adoption of spherical harmonics in the spectral method eliminates the singularity of the Fokker–Planck equation in spherical coordinates, and provides high precision and efficiency. The evolving solution of orientation distribution with Pe=∞ is obtained through the solution of rotational dynamics. Using a regular perturbation method, the solution of orientation distribution with Pe=∞ is extended for the condition of Pe⪢1. This paper provides systematical and high efficient techniques to deal with the fiber orientation.
The antisynchronization of a class of chaotic delayed neural networks
Authors: Zhu Huibin , Cui Baotong
Published: November 2007

In this paper, the antisynchronization problems of a class of chaotic delayed neural networks are investigated. Some criteria of the antisynchronization of the chaotic delayed neural networks are established by using the linear matrix inequality and Lyapunov stability theory. These criteria not only improve and generalize some known results, but are also some less conservative conditions. Finally, two numerical examples and the corresponding numerical simulations are used to illustrate the effectiveness of the obtained results.
Single bacterial cell detection with nonlinear rotational frequency shifts of driven magnetic microspheres
Authors: McNaughton Brandon H. , Agayan Rodney R. , Clarke Roy , Smith Ron G. , Kopelman Raoul
Published: November 2007

Shifts in the nonlinear rotational frequency of magnetic microspheres, driven by an external magnetic field, offer a dynamic approach for the detection of single bacterial cells. We demonstrate this capability by optically measuring such frequency shifts when an Escherichia coli attaches to the surface of a 2.0μm magnetic microsphere, thereby affecting the drag of the system. From this change in drag, the nonlinear rotation rate was reduced, on average, by a factor of 3.8. Sequential bacterial cell attachments were also monitored.
A numerical model for explaining the role of the interface morphology in composite solar cells
Authors: Martin C. M. , Burlakov V. M. , Assender H. E. , Barkhouse D. A. R.
Published: November 2007

We have developed a numerical model that simulates the operation of organic∕inorganic photovoltaic devices. Using this model, we have investigated the effect of the interface morphology and have shown that for a given system, there is both a most efficient device thickness and the interfacial feature size for overall power conversion. The variation of current-voltage (I-V) curves with differing recombination rates, anode barrier height, and light intensity has been simulated with reducing the recombination rate and lowering the anode barrier height shown to lead to improved open circuit voltages and fill factors. Through this model, we show that the increase in fill factor observed when the lithium salt Li[CF3SO2]2N is added to devices can be explained by an increase in the polymer hole mobility.
High speed resistive switching in Pt∕TiO2∕TiN film for nonvolatile memory application
Authors: Yoshida Chikako , Tsunoda Kohji , Noshiro Hideyuki , Sugiyama Yoshihiro
Published: November 2007

We have fabricated and investigated the bipolar resistive switching characteristics of Pt/rutile-TiO2∕TiN devices for resistance memory applications. Data writing for five-level resistance states has been demonstrated by varying the amplitude of 5ns voltage pulses. In addition, data retention of more than 256h at 85°C and an excellent endurance of over 2×106cycles have been confirmed. These results indicate that Pt∕TiO2∕TiN devices have a potential for nonvolatile multiple-valued memory devices.
Nondestructive evaluation of microcracks by laser-induced focused ultrasound
Authors: Kozhushko Victor V. , Hess Peter
Published: November 2007

Photoacoustic transformation of laser pulses at a concave stainless steel surface immersed in water delivered short, focused, ultrasonic pressure pulses to the free surface of a sample placed in the focal region. The probe-beam-deflection method was employed to detect the resulting transient surface slope of the surface distortions in the frequency range ⩽100MHz. Absolute calibration of the setup indicates strains of ∼10−3. Clear evidence for characteristic changes in the transient waveforms was observed near single cracks at the surface. Therefore, this novel method is suitable for nondestructive evaluation and characterization of bulk and surface defects.
Global climate change, war, and population decline in recent human history
Authors: Zhang David D. , Brecke Peter , Lee Harry F. , He Yuan-Qing , Zhang Jane
Published: November 2007

Although scientists have warned of possible social perils resulting from climate change, the impacts of long-term climate change on social unrest and population collapse have not been quantitatively investigated. In this study, high-resolution paleo-climatic data have been used to explore at a macroscale the effects of climate change on the outbreak of war and population decline in the preindustrial era. We show that long-term fluctuations of war frequency and population changes followed the cycles of temperature change. Further analyses show that cooling impeded agricultural production, which brought about a series of serious social problems, including price inflation, then successively war outbreak, famine, and population decline successively. The findings suggest that worldwide and synchronistic war–peace, population, and price cycles in recent centuries have been driven mainly by long-term climate change. The findings also imply that social mechanisms that might mitigate the impact of climate change were not significantly effective during the study period. Climate change may thus have played a more important role and imposed a wider ranging effect on human civilization than has so far been suggested. Findings of this research may lend an additional dimension to the classic concepts of Malthusianism and Darwinism.
Construction of effective free energy landscape from single-molecule time series
Authors: Baba Akinori , Komatsuzaki Tamiki
Published: November 2007

A scheme for extracting an effective free energy landscape from single-molecule time series is presented. This procedure uniquely identifies a non-Gaussian distribution of the observable associated with each local equilibrium state (LES). Both the number of LESs and the shape of the non-Gaussian distributions depend on the time scale of observation. By assessing how often the system visits and resides in a chosen LES and escapes from one LES to another (with checking whether the local detailed balance is satisfied), our scheme naturally leads to an effective free energy landscape whose topography depends on in which time scale the system experiences the underlying landscape. For example, two metastable states are unified as one if the time scale of observation is longer than the escape time scale for which the system can visit mutually these two states. As an illustrative example, we present the application of extracting the effective free energy landscapes from time series of the end-to-end distance of a three-color, 46-bead model protein. It indicates that the time scales to attain the local equilibrium tend to be longer in the unfolded state than those in the compact collapsed state.
Redirection of cutaneous sensation from the hand to the chest skin of human amputees with targeted reinnervation
Authors: Kuiken Todd A. , Marasco Paul D. , Lock Blair A. , Harden R. Norman , Dewald Julius P. A.
Published: November 2007

Amputees cannot feel what they touch with their artificial hands, which severely limits usefulness of those hands. We have developed a technique that transfers remaining arm nerves to residual chest muscles after an amputation. This technique allows some sensory nerves from the amputated limb to reinnervate overlying chest skin. When this reinnervated skin is touched, the amputees perceive that they are being touched on their missing limb. We found that touch thresholds of the reinnervated chest skin fall within near-normal ranges, indicating the regeneration of large-fiber afferents. The perceptual identity of the limb and chest was maintained separately even though they shared a common skin surface. A cutaneous expression of proprioception also occurred in one reinnervated individual. Experiments with peltier temperature probes and surface electrical stimulation of the reinnervated skin indicate the regeneration of small diameter temperature and pain afferents. The perception of an amputated limb arising from stimulation of reinnervated chest skin may allow useful sensory feedback from prosthetic devices and provides insight into the mechanisms of neural plasticity and peripheral regeneration in humans.
Phloem loading in
Verbascum phoeniceum
L. depends on the synthesis of raffinose-family oligosaccharides
Authors: McCaskill Ashlee , Turgeon Robert
Published: November 2007

Phloem loading is the initial step in photoassimilate export and the one that creates the driving force for mass flow. It has been proposed that loading occurs symplastically in species that translocate carbohydrate primarily as raffinose family oligosaccharides (RFOs). In these plants, dense fields of plasmodesmata connect bundle sheath cells to specialized companion cells (intermediary cells) in the minor veins. According to the polymer trap model, advanced as a mechanism of symplastic loading, sucrose from the mesophyll diffuses into intermediary cells and is converted there to RFOs. This process keeps the sucrose concentration low and, because of the larger size of the RFOs, prevents back diffusion. To test this model, the RFO pathway was down-regulated in
Verbascum phoeniceum
L. by suppressing the synthesis of galactinol synthase (GAS), which catalyzes the first committed step in RFO production. Two
GAS
genes (
VpGAS1
and
VpGAS2
) were cloned and shown to be expressed in intermediary cells. Simultaneous RNAi suppression of both genes resulted in pronounced inhibition of RFO synthesis. Phloem transport was negatively affected, as evidenced by the accumulation of carbohydrate in the lamina and the reduced capacity of leaves to export sugars during a prolonged dark period. In plants with severe down-regulation, additional symptoms of reduced export were obvious, including impaired growth, leaf chlorosis, and necrosis and curling of leaf margins.
Analysis of 81 genes from 64 plastid genomes resolves relationships in angiosperms and identifies genome-scale evolutionary patterns
Authors: Jansen Robert K. , Cai Zhengqiu , Raubeson Linda A. , Daniell Henry , dePamphilis Claude W. , Leebens-Mack James , Müller Kai F. , Guisinger-Bellian Mary , Haberle Rosemarie C. , Hansen Anne K. , Chumley Timothy W. , Lee Seung-Bum , Peery Rhiannon , McNeal Joel R. , Kuehl Jennifer V. , Boore Jeffrey L.
Published: November 2007

Angiosperms are the largest and most successful clade of land plants with >250,000 species distributed in nearly every terrestrial habitat. Many phylogenetic studies have been based on DNA sequences of one to several genes, but, despite decades of intensive efforts, relationships among early diverging lineages and several of the major clades remain either incompletely resolved or weakly supported. We performed phylogenetic analyses of 81 plastid genes in 64 sequenced genomes, including 13 new genomes, to estimate relationships among the major angiosperm clades, and the resulting trees are used to examine the evolution of gene and intron content. Phylogenetic trees from multiple methods, including model-based approaches, provide strong support for the position of
Amborella
as the earliest diverging lineage of flowering plants, followed by Nymphaeales and Austrobaileyales. The plastid genome trees also provide strong support for a sister relationship between eudicots and monocots, and this group is sister to a clade that includes Chloranthales and magnoliids. Resolution of relationships among the major clades of angiosperms provides the necessary framework for addressing numerous evolutionary questions regarding the rapid diversification of angiosperms. Gene and intron content are highly conserved among the early diverging angiosperms and basal eudicots, but 62 independent gene and intron losses are limited to the more derived monocot and eudicot clades. Moreover, a lineage-specific correlation was detected between rates of nucleotide substitutions, indels, and genomic rearrangements.
Delayed leaf senescence induces extreme drought tolerance in a flowering plant
Authors: Rivero Rosa M. , Kojima Mikiko , Gepstein Amira , Sakakibara Hitoshi , Mittler Ron , Gepstein Shimon , Blumwald Eduardo
Published: November 2007

Drought, the most prominent threat to agricultural production worldwide, accelerates leaf senescence, leading to a decrease in canopy size, loss in photosynthesis and reduced yields. On the basis of the assumption that senescence is a type of cell death program that could be inappropriately activated during drought, we hypothesized that it may be possible to enhance drought tolerance by delaying drought-induced leaf senescence. We generated transgenic plants expressing an isopentenyltransferase gene driven by a stress- and maturation-induced promoter. Remarkably, the suppression of drought-induced leaf senescence resulted in outstanding drought tolerance as shown by, among other responses, vigorous growth after a long drought period that killed the control plants. The transgenic plants maintained high water contents and retained photosynthetic activity (albeit at a reduced level) during the drought. Moreover, the transgenic plants displayed minimal yield loss when watered with only 30% of the amount of water used under control conditions. The production of drought-tolerant crops able to grow under restricted water regimes without diminution of yield would minimize drought-related losses and ensure food production in water-limited lands.
Vitamin B1 biosynthesis in plants requires the essential iron–sulfur cluster protein, THIC
Authors: Raschke Maja , Bürkle Lukas , Müller Nadine , Nunes-Nesi Adriano , Fernie Alisdair R. , Arigoni Duilio , Amrhein Nikolaus , Fitzpatrick Teresa B.
Published: November 2007

Vitamin B1 (thiamin) is an essential compound in all organisms acting as a cofactor in key metabolic reactions and has furthermore been implicated in responses to DNA damage and pathogen attack in plants. Despite the fact that it was discovered almost a century ago and deficiency is a widespread health problem, much remains to be deciphered about its biosynthesis. The vitamin is composed of a thiazole and pyrimidine heterocycle, which can be synthesized by prokaryotes, fungi, and plants. Plants are the major source of the vitamin in the human diet, yet little is known about the biosynthesis of the compound therein. In particular, it has never been verified whether the pyrimidine heterocycle is derived from purine biosynthesis through the action of the THIC protein as in bacteria, rather than vitamin B6 and histidine as demonstrated for fungi. Here, we identify a homolog of THIC in
Arabidopsis
and demonstrate its essentiality not only for vitamin B1 biosynthesis, but also plant viability. This step takes place in the chloroplast and appears to be regulated at several levels, including through the presence of a riboswitch in the 3′-untranslated region of THIC. Strong evidence is provided for the involvement of an iron–sulfur cluster in the remarkable chemical rearrangement reaction catalyzed by the THIC protein for which there is no chemical precedent. The results suggest that vitamin B1 biosynthesis in plants is in fact more similar to prokaryotic counterparts and that the THIC protein is likely to be the key regulatory protein in the pathway.
Acute-phase protein α-1-acid glycoprotein mediates neutrophil migration failure in sepsis by a nitric oxide-dependent mechanism
Authors: Mestriner F. L. A. C. , Spiller F. , Laure H. J. , Souto F. O. , Tavares-Murta B. M. , Rosa J. C. , Basile-Filho A. , Ferreira S. H. , Greene L. J. , Cunha F. Q.
Published: November 2007

The reduction of circulating neutrophil migration to infection sites is associated with a poor outcome of severe sepsis. α-1-Acid glycoprotein (AGP) was isolated from the sera of severely septic patients by HPLC and acrylamide gel electrophoresis and identified by mass spectrometry. Both the isolated protein and commercial AGP inhibited carrageenin-induced neutrophil migration into the rat peritoneal cavity when administered i.v. at a dose of 4.0 μg per rat (95 pmol per rat). Analysis by intravital microscopy demonstrated that both proteins inhibited the rolling and adhesion of leukocytes in the mesenteric microcirculation. The inhibitory activity was blocked by 50 mg/kg aminoguanidine, s.c., and was not demonstrable in inducible nitric oxide synthase (iNOS) knockout mice. Incubation of AGP with neutrophils from healthy subjects induced the production of NO and inhibited the neutrophil chemotaxis by an iNOS/NO/cyclic guanosine 3,5-monophosphate-dependent pathway. In addition, AGP induced thel-selectin shedding by neutrophils. The administration of AGP to rats with mild cecal ligation puncture sepsis inhibited neutrophil migration and reduced 7-day survival from ≈80% to 20%. These data demonstrate that AGP, an acute-phase protein, inhibits neutrophil migration by an NO-dependent process and suggest that AGP also participates in human sepsis.
Mononeme: A new secretory organelle in
Plasmodium falciparum
merozoites identified by localization of rhomboid-1 protease
Authors: Singh Subhash , Plassmeyer Matthew , Gaur Deepak , Miller Louis H.
Published: November 2007

Compartmentalization of proteins into subcellular organelles in eukaryotic cells is a fundamental mechanism of regulating complex cellular functions. Many proteins of
Plasmodium falciparum
merozoites involved in invasion are compartmentalized into apical organelles. We have identified a new merozoite organelle that contains
P. falciparum
rhomboid-1 (PfROM1), a protease that cleaves the transmembrane regions of proteins involved in invasion. By immunoconfocal microscopy, PfROM1 was localized to a single, thread-like structure on one side of the merozoites that appears to be in close proximity to the subpellicular microtubules. PfROM1 was not found associated with micronemes, rhoptries, or dense granules, the three identified secretory organelles of invasion. Release of merozoites from schizonts resulted in the movement of PfROM1 from the lateral asymmetric localization to the merozoite apical pole and the posterior pole. We have named this single thread-like organelle in merozoites, the mononeme.