bluuebunny/crossref_metadata_2025 huggingface dataset:
Planetary and synoptic scale adjustment of the Arctic atmosphere to sea ice cover changes
Authors: Sokolova E. , Dethloff K. , Rinke A. , Benkel A.
Published: September 2007

By means of unforced simulations with a global coupled circulation model it is shown that naturally occurring changes between high and low sea ice cover phases of the Arctic Ocean exert a strong influence on the Northern Hemisphere storm tracks. This work emphasizes the nonlinear dynamical feedback between Arctic sea ice cover and the Arctic Oscillation (AO) such as atmospheric response depending upon the wintertime sea ice distribution. Two seven year long time slices, with high and low sea ice cover, were analyzed with respect to the feedbacks between the time‐mean flow, the quasi‐stationary planetary and the baroclinic waves. The wave energy fluxes on time scales of 2 to 6 days increase in the middle troposphere between 30 and 60°N during the high sea ice phase and increase the zonal wind. This increase is compensated by a strong reduction in the Eliassen‐Palm fluxes on time scales from 10 to 90 days between 60 and 70°N during high sea ice phases, accompanied by reduced zonal winds. High sea ice cover phases are related to the zonal wind changes during the positive phases of the AO, especially over the northern part of the Atlantic Ocean.
Observing the moist troposphere with radio occultation signals from COSMIC
Authors: Sokolovskiy S. V. , Rocken C. , Lenschow D. H. , Kuo Y.‐H. , Anthes R. A. , Schreiner W. S. , Hunt D. C.
Published: September 2007

New approaches for observing the moist troposphere using radio occultation (RO) signals transformed to impact parameter representation by radio‐holographic (RH) methods are presented. Large changes in the RH bending angle are used as indicators of significant vertical refractivity gradients that often occur on top of the atmospheric boundary layer (ABL), convective cloud layers such as the trade‐wind inversion, and other moist layers in the free troposphere. RH amplitude fluctuations are used as an indicator of turbulence in the moist troposphere. The approaches are demonstrated using RO data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) mission from September 2006. The global distributions of the ABL depths and tops of moist convective layers derived from COSMIC RO data correspond generally to the observed locations and structures of the Intertropical Convergence Zone and adjacent sub‐tropical regions. The approaches are suitable for investigations of the temporal and spatial ABL variability.
Temporary topological trapping and escape of charged particles in a flux tube as a cause of delay in time asymptotic transport
Authors: Tooprakai P. , Chuychai P. , Minnie J. , Ruffolo D. , Bieber J. W. , Matthaeus W. H.
Published: September 2007

The scenario of temporary trapping of magnetic field lines and their subsequent suppressed diffusive escape from topological magnetic structures embedded in turbulence has been offered as a way to understand the persistence of “dropouts”, or sharp gradients in observed heliospheric energetic particle intensities. Here a set of numerical experiments is carried out to show the basic physics of this process: charged test particles can be temporarily trapped in flux tubes and then escape due to random turbulent perturbations in the magnetic field. The overall effect is a delay in the onset of time‐asymptotic transport. We thus confirm that previous arguments based on field line transport are also applicable to test particle transport.
Topographic influences on wildfire consumption of soil organic carbon in interior Alaska: Implications for black carbon accumulation
Authors: Kane E. S. , Kasischke E. S. , Valentine D. W. , Turetsky M. R. , McGuire A. D.
Published: September 2007

We measured characteristics of soil organic carbon (SOC) and black carbon (BC) along opposed north‐ and south‐facing toposequences in recent (2004) and old (∼1860–1950) burn sites throughout interior Alaska. Surface fuel consumption did not vary between different topographic positions, with 3.3 (±0.5) kg C m−2 being consumed on toe slope sites, 4.0 (±0.2) kg C m−2 on north‐slope sites, and 3.6 (±0.3) kg C m−2 on south‐slope sites. On a relative scale, 43% of the organic matter depth was removed through biomass burning on toe slopes, 62% on north‐slopes, and 77% on south‐slope sites. Mineral soil BC stocks (measured using a chemical/thermal oxidation method isolating more graphitic BC) ranged from 112 ± 24 g C m−2 to 173 ± 43 g C m−2 on north‐ and south‐facing aspects, respectively. These data supported the expectation that deeper and wetter ground fuels occurring in north‐facing and toe‐slope forests burned less completely, which decreased the amount of BC incorporated into mineral soil where it could be protected from subsequent fires. Thus, warmer and drier forests harbored less total SOC, but following wildfire aggraded larger BC stocks. BC was therefore an important component of stable soil C in warmer and drier forests which had higher C turnover rates in other soil pools (determined by density fractionation, δ13C, and Δ14C). These data provide a basis for understanding how variable patterns of organic layer depths and soil moisture mediate the consumption of SOC in wildfire, as well as the long‐term accumulation of BC.
Little River Experimental Watershed, Tifton, Georgia, United States: A historical geographic database of conservation practice implementation
Authors: Sullivan D. G. , Batten H. L.
Published: September 2007

The Little River Experimental Watershed located in the headwaters of the Upper Suwannee River basin is one of twelve national benchmark watersheds participating in the U.S. Department of Agriculture (USDA) Conservation Effects Assessment Project–Watershed Assessment Studies (CEAP‐WAS). Historical paper files and maps (circa 1980–2006) were collected and used to develop a geographic database of conservation practices supported by the USDA Natural Resource Conservation Service. The CEAP‐WAS database can be queried by conservation practice, total acreages enrolled, year of implementation, and location. The CEAP‐WAS database is integral to understanding the links between conservation practice implementation and placement with observed changes in hydrologic processes within a small southern Coastal Plain watershed. All associated geographic information has been provided in shapefile format and has been projected into universal transverse Mercator coordinates (zone 17), using NAD83 as the datum and GRS80 as the ellipsoid. Data may be accessed via ftp://www.tiftonars.org/, archived in a folder named ceap_data.
Mechanisms underlying the anti‐inflammatory activity and gastric safety of acemetacin
Authors: Chávez‐Piña A E , McKnight W , Dicay M , Castañeda‐Hernández G , Wallace J L
Published: September 2007

Background and purpose:

Acemetacin is regarded as a pro‐drug of indomethacin and induces significantly less gastric damage but the reasons for this greater gastric safety of acemetacin are unclear. The anti‐inflammatory effects of acemetacin have been attributed, at least in part, to its hepatic biotransformation to indomethacin. The aim of this study was to determine the effects of acemetacin and indomethacin in an in vivo model of acute inflammation and to examine the importance of biotransformation of acemetacin (to indomethacin) to its anti‐inflammatory actions.

Experimental approach:

The zymosan airpouch model was used in rats. Indomethacin or acemetacin (2.7–83.8 μmol kg−1) were administered orally or directly into the pouch. Leukocyte infiltration, prostaglandin (PG) E2 and leukotriene (LT) B4 levels in exudates, and whole blood thromboxane (TX) B2 synthesis were measured.

Key results:

Acemetacin was rapidly converted to indomethacin after its administration. Both acemetacin and indomethacin elicited comparable, dose‐dependent reductions of leukocyte infiltration and of PGE2 and TXB2 synthesis. However, indomethacin induced more gastric damage than acemetacin and elevated LTB4 production in the airpouch.

Conclusions and implications:

The similar effects of acemetacin and indomethacin on leukocyte infiltration and PG synthesis are consistent with rapid biotransformation of acemetacin to indomethacin. Some of this biotransformation may occur extra‐hepatically, for instance in inflammatory exudates. Acemetacin probably exerts actions independent of conversion to indomethacin, given the different effects of these two drugs on LTB4 production. Such differences may contribute to the relative gastric safety of acemetacin compared to indomethacin.

British Journal of Pharmacology (2007) 152, 930–938; doi:10.1038/sj.bjp.0707451; published online 17 September 2007
Semiclassical treatments for small-molecule dynamics in low-temperature crystals using fixed and adiabatic vibrational bases
Authors: Chapman Craig T. , Cina Jeffrey A.
Published: September 2007

Time-resolved coherent nonlinear optical experiments on small molecules in low-temperature host crystals are exposing valuable information on quantum mechanical dynamics in condensed media. We make use of generic features of these systems to frame two simple, comprehensive theories that will enable the efficient calculations of their ultrafast spectroscopic signals and support their interpretation in terms of the underlying chemical dynamics. Without resorting to a simple harmonic analysis, both treatments rely on the identification of normal coordinates to unambiguously partition the well-structured guest-host complex into a system and a bath. Both approaches expand the overall wave function as a sum of product states between fully anharmonic vibrational basis states for the system and approximate Gaussian wave packets for the bath degrees of freedom. The theories exploit the fact that ultrafast experiments typically drive large-amplitude motion in a few intermolecular degrees of freedom of higher frequency than the crystal phonons, while these intramolecular vibrations indirectly induce smaller-amplitude—but still perhaps coherent—motion among the lattice modes. The equations of motion for the time-dependent parameters of the bath wave packets are fairly compact in a fixed vibrational basis/Gaussian bath (FVB/GB) approach. An alternative adiabatic vibrational basis/Gaussian bath (AVB/GB) treatment leads to more complicated equations of motion involving adiabatic and nonadiabatic vector potentials. Computational demands for propagation of the parameter equations of motion appear quite manageable for tens or hundreds of atoms and scale similarly with system size in the two cases. Because of the time-scale separation between intermolecular and lattice vibrations, the AVB/GB theory may in some instances require fewer vibrational basis states than the FVB/GB approach. Either framework should enable practical first-principles calculations of nonlinear optical signals from molecules in cryogenic matrices and their semiclassical interpretation in terms of electronic and vibrational decoherence and vibrational population relaxation, all within a pure-state description of the macroscopic many-body complex.
Experimental study of internal gravity waves generated by supercritical topography
Authors: Zhang H. P. , King B. , Swinney Harry L.
Published: September 2007

Oscillatory tides flowing over rough topography on the ocean floor generate internal gravity waves, which are a major source of ocean mixing. Linear inviscid theory can describe waves generated by gentle topography with slopes that are less steep than the propagation angle of the internal waves; such topography is termed subcritical. However, a clear physical picture of internal waves generated by topography with slopes steeper than the angle of internal waves (supercritical topography) is lacking. In this paper we present an experimental study at Reynolds number ∼O(100) of internal gravity waves generated by a circular cylinder that oscillates horizontally (at a frequency Ω), thus mimicking barotropic tidal flow over bottom topography. Fundamental waves of frequency Ω emanate from locations on the cylinder where the topographic slope equals the slope of internal waves. For small oscillating amplitude A (weak forcing), our experimental results compare well with predictions of the viscous linear theory of D. G. Hurley and G. Keady [J. Fluid Mech. 351, 119 (1997)]. The width of the wave beams is determined by competition between forcing and viscous smoothing, and hydrodynamic screening of the steep part of the topography extends the cylinder’s horizontal length scale. Beyond the weak forcing regime, harmonic waves of frequency nΩ (with integer n>1 and nΩ<N, where N is the buoyancy frequency) are generated mainly by nonlinear interaction involving the overlapping fundamental waves. For moderate forcing we find that the intensity of the fundamental and second harmonic waves scales linearly and quadratically with A, respectively.
Stability of stratified natural convection in a tall vertical annular cavity
Authors: Prud’homme Michel , Le Quéré Patrick
Published: September 2007

The stability of buoyancy-driven convection between vertical concentric cylinders is examined under vertical thermal stratification conditions, with a uniform temperature gap between the cylinders. Analytical solutions are derived for the parallel base flow. Critical Rayleigh numbers are determined from these solutions at various Prandtl numbers, stratification levels, and inner to outer radius ratios. Nonaxisymmetric critical disturbances can be found for low radius ratios and small Prandtl numbers, but are otherwise symmetric and usually occur in the form of travelling waves opposite to gravity, except at large Prandtl numbers and for strong stratification where the direction of propagation is reversed. The effect of curvature is to favor the onset of instability at any stratification level, for moderate and large Prandtl numbers. For small Prandtl numbers, curvature has a stabilizing effect at low stratification levels and is most influential at moderate levels. Computation of the Landau coefficient reveals that the bifurcations are at times subcritical, depending on the parameter values.
Wavelength-dependent fragmentation and clustering observed after femtosecond laser ablation of solid C60
Authors: Kobayashi T. , Kato T. , Matsuo Y. , Kurata-Nishimura M. , Hayashizaki Y. , Kawai J.
Published: September 2007

We report here the resonance effect in femtosecond laser ablation of solid C60 by investigating wavelength and fluence dependence of product ion species. When the ablation laser wavelength is far from the molecular absorption band of C60, we observe both C60−2n+ fragment ions and C60+2n+ cluster ions as well as C60+ parent ion. Delayed ionization of C60 is not significant. When the ablation laser wavelength is near resonant with the molecular absorption, we observe C60+ and some amount of C60−2n+ fragment ions depending on the laser fluence. Delayed ionization of C60 is significant in this case, which indicates high internal energy of C60 molecule. From the observations, we confirm the strong coupling of femtosecond laser energy with C60 molecule when the molecular absorption is high at the ablation laser wavelength.
Wafer dependence of Johnsen–Rahbek type electrostatic chuck for semiconductor processes
Authors: Qin Shu , McTeer Allen
Published: September 2007

A Johnsen–Rahbek (J-R type) type electrostatic chuck (ESC) was found to be more sensitive to wafer conditions than classic ESC, including backside dielectric quality and thickness and doping level. The wafer backside dielectric may reduce the clamp force and increase the declamping time, depending on dielectric quality, dielectric thickness, and ESC configurations. These issues and their mechanisms are studied extensively and potential solutions are proposed.
Determination of the effective permittivity of dielectric mixtures with the transmission line matrix method
Authors: Blanchard Cédric , Portí Jorge A. , Morente Juan A. , Salinas Alfonso , Navarro Enrique A.
Published: September 2007

In this article, the effective permittivity of two-phase dielectric mixtures is calculated by applying the transmission line matrix (TLM) method. Two slightly different TLM algorithms are considered: a hybrid approach, which combines the TLM method with a subgriding technique based on dual capacitor circuits, to allow a refined description of the material, and a standard or pure TLM approach, which uses a mesh size smaller than the typical dimension of insertions in order to appropriately describe details of the geometry. A study of the statistical distribution of permittivity for insertions in random positions is also presented, showing that the effective permittivity of the mixture tends to concentrate around the mean value as insertions reduce in size. Both TLM techniques are applied to dielectric mixtures in two-dimensional situations. When the concentration of insertions is small, the results are in close agreement with prediction formulae while for higher concentration values, deviations are observed, although basically the results fall within the range predicted by theoretical bounds. Numerical results obtained using the two TLM approaches present a similar qualitative behavior; nevertheless, a clear difference is observed between them. The study of special periodic situations with coated insertions allows us to identify the pure TLM results as more accurate than those of the hybrid approach and also explains why homogeneous distributions provide numerical values close to the theoretical limits. The effects of shape on permittivity are also modeled and deviations to the Wiener bounds are discussed in detail, using two- and three-dimensional examples in practical situations.
Simultaneous sudden changes of electrical behavior at the threshold in laser diodes
Authors: Feng L. F. , Li D. , Zhu C. Y. , Wang C. D. , Cong H. X. , Xie X. S. , Lu C. Z.
Published: September 2007

Precise ac electrical measurements as well as dc I-V plots at forward bias have been used to characterize multi-quantum-well (MQW) laser diodes. Step offsets of apparent conductance, apparent capacitance, junction voltage, series resistance, and ideality factor at lasing threshold were observed. To compare the electrical characteristics of different diodes numerical simulations of the IdV∕dI-I curve of the double-heterostructure (DH) laser were performed. We find that the conventional model used to explain this curve is not very satisfactory. Our simulations demonstrate that the junction voltage, series resistance, and ideality factor for both DH and MQW lasers exhibit the same sudden changes at threshold. Perhaps the electrical behavior near threshold for all laser diodes is very similar.
Nonlinear capacitance dilatometry for investigating elastic and electromechanical properties of ferroelectrets
Authors: Bauer-Gogonea S. , Camacho-Gonzalez F. , Schwödiauer R. , Ploss B. , Bauer S.
Published: September 2007

Nonlinearities in ferroelectret polymer foam capacitors arise from voltage-dependent thickness changes. Such thickness changes are caused by the converse piezoelectric and electrostrictive effects in these soft materials. The authors show that the higher harmonics of the current response during application of a sinusoidal voltage to ferroelectret capacitors provide information on the elastic and electromechanical properties of the foam. The authors demonstrate the potential of this versatile measurement technique by investigating the temperature dependence of the piezoelectric response and by monitoring the changes in the elastic and electromechanical properties during inflation of cellular polypropylene.
Photoemission study of the electronic structures of tris-(8-hydroxyquinoline) aluminum/Li2O∕Al interfaces
Authors: Cho K. , Cho S. W. , Whang C.-N. , Jeong K. , Kang S. J. , Yi Y.
Published: September 2007

The electronic structures of tris-(8-hydroquinoline) aluminum (Alq3)∕Li2O∕Al interfaces were studied using in situ ultraviolet and x-ray photoelectron spectroscopies (UPS and XPS). The UPS and XPS spectra allowed us to evaluate the complete energy level diagrams and to analyze the chemical interactions at the interfaces. Inserting Li2O between Al and Alq3 led to the highest occupied molecular orbital (HOMO) of Alq3 shifting to a higher binding energy compared to that without Li2O, which resulted in an improved electron injection. We also observed that the magnitude of the secondary cutoff shift was almost identical to that of the HOMO shift with the insertion of Li2O. This implies that the energy level alignment depends on the interface dipole and ionization energy of the adsorbate. Additionally, a gap state was observed in the gap of Alq3, which is related to the interfacial reaction. The N 1s spectra revealed that there were destructive chemical reactions between Alq3 and Al, which could be prevented by inserting Li2O between them.
Profiling teachers' professional learning practices and values: differences between and within schools
Authors: Pedder David
Published: September 2007

This article reports findings from a survey of the values and perceived practices of 1212 members of staff in 32 schools in England participating in the ‘Learning How to Learn’ (LHTL) project in relation to teachers' professional learning. Through factor analysis four underlying dimensions of teachers' learning practices were developed. These dimensions appear to reflect a demarcation between teachers' in‐class and out‐of‐class learning. Overall, practices and values for teachers' classroom contextualized learning were lower than for out‐of‐class learning. Through cluster analysis teachers were grouped according to their reported levels of practice on the four dimensions of teachers' learning. Five distinctive clusters of teachers were identified, each cluster with a distinctive teacher learning profile. The main findings are that there are systematic differences between schools in terms of the mix of their teachers' learning profiles. There are also important differences between staff working in primary and secondary schools. In addition, there are significant differences within school between senior and middle managers, teachers with little or no managerial responsibility and support staff, and between secondary teachers of different subjects. This diversity of teachers' learning underpins the need for schools to develop more differentiated strategies for supporting continuous learning among different groups of staff.
Cultural shifts in teaching: new workforce, new professionalism?
Authors: Storey Anne
Published: September 2007

The last two decades have been witness to the introduction of a series of interlocking government‐led initiatives ostensibly designed to establish and raise performance standards in teaching and learning. These include target‐setting, assessments, appraisals, performance management systems and performance thresholds. Such measures have often been characterized as part of the ‘modernization’ of the profession. This plethora of initiatives has been met with a severe critique from many educationalists. Much education research literature has vigorously critiqued the erosion of creativity and professionalism in favour of a regime of ‘managerialism’ and ‘performativity’. However, a number of recent changes to the composition and nature of the workforce, with attendant shifts in their expectations and experiences, may now be presenting a challenge to that critique. Growing numbers of mid‐career new entrants to the teacher workforce with prior experience of targets, objectives and routine assessment, may trigger and result in a greater receptivity to the modernizing apparatus. Together with workforce remodelling, there may now be signs of some significant shifts in the teacher workforce and their receptivity to changes of this kind. This article draws on a study of a proxy sample of this new workforce and assesses their meaning systems and expectations. It finds evidence of their willingness to engage both with the language and the methods of performance and an ease with the characteristic features of the ‘new professionalism’. The influence and example of this segment of the new workforce may result in the standard critique appearing less relevant to the concerns of practising teachers than it once was.
From narratives to portraits: methodology and methods to portray leadership
Authors: Waterhouse Joanne
Published: September 2007

This article outlines the planning towards a research design to learn about leadership as it is constructed, experienced and developed in schools. It is intended that the research would go beyond an individual's account to gain an insight into the relationships and social dynamic within the organization. The hypothesis is that the degree of distributive leadership that exists within a school is a measure of the trust and respect between individuals. In particular, the issues of reflexivity and voice in research are considered. The author proposes that a study of leadership narratives can be developed into a layered, textured portrait.
School‐based teacher development in Sub‐Saharan Africa: building a new research agenda
Authors: Moon Bob
Published: September 2007

This article explores and analyses the context of school‐based teacher development in Sub‐Saharan Africa. The argument is made that many aspects of the teacher problem in these regions mirror those in the rest of the world, but the size and scale of the need makes the challenge of providing schools and teachers to achieve ‘Education for All’ (EFA) one of the world's biggest educational problems. As such, a response from the global community, parallel to similar initiatives in health, is required. The context of the problem is set out, particularly the inevitability of creating new school‐based modes of teacher development. The analysis draws extensively on the work of the Teacher Education in Sub‐Saharan Africa (TESSA) research programme. The article then goes on to suggest: (1) the revolution in communication technologies provides an opportunity radically to reassess the forms and modes of teacher development, particularly in rural areas; and (2) there is a need for research and development activity to provide the foundation upon which such potential can be realized. In this context a new ‘architecture for teacher development’ needs putting in place, a process that should be a mainstream concern for the world's education research community.
The classroom in your pocket?1
Authors: Power Tom , Thomas Rhodri
Published: September 2007

Research exploring the ways in which information communication technologies (ICTs) could improve access to, and the quality of, teacher education in the global south (Leach et al., 2006) showed that when teachers were given sustained training, support and access to laptop and handheld computers, they found the handheld and laptop computers equally useful, both as tools for their own professional development and as tools for supporting classroom practices. Those who expressed a preference for one device over the other identified the handheld computer as the best tool for supporting teacher professional development and practice, particularly in rural communities.

This article reports the findings of a recent one‐year project which built on the previous research, but which focused solely on the potential of handheld computers for teacher professional development. Many studies have investigated the use of handheld computers in classroom settings but most of these focus on pupil learning (e.g. Fung et al., 1998; Yarnall et al., 2003). There is not yet a substantial body of literature on the potential of handhelds for teacher education, although Soloway (2002) argues that handhelds provide an opportunity for making major changes in educational settings.

In this study, the teachers themselves used the analytical framework for teacher professional knowledge developed by Banks et al. (1999) to consider their own experiences with the handheld computers. This study finds that handheld digital tools offer a number of pedagogic and pragmatic advantages over laptop or desktop computers for teachers, especially in rural communities. However, further technical development is required fully to orient the devices to classroom practices (as opposed to the ‘office’ or ‘business’ orientation).
Supporting the professional development of teaching assistants: classroom teachers' perspectives on their mentoring role
Authors: Burgess Hilary , Mayes Ann Shelton
Published: September 2007

The training of teaching assistants in the UK is undergoing considerable change linked to workforce reform in primary schools. This article examines the role that class teachers play as mentors in the training of teaching assistants on two types of programmes operating in England leading to Higher Level Teaching Assistant Professional Status. It considers the qualities required for mentoring teaching assistants compared to mentoring trainee teachers. The views and perspectives of a group of thirty‐four school teachers who have carried out a mentor role for both a trainee primary teacher and a primary teaching assistant are analysed. The research aims to identify the common skills, strategies and approaches used by the school‐based mentors and identify the perceived tensions and challenges facing these mentors.
Focus Identification during Sentence Comprehension: Evidence from Eye Movements
Authors: Paterson Kevin B. , Liversedge Simon P. , Filik Ruth , Juhasz Barbara J. , White Sarah J. , Rayner Keith
Published: September 2007

Three eye movement experiments investigated focus identification during sentence comprehension. Participants read dative or double-object sentences (i.e., either the direct or indirect object occurred first), and a replacive continuation supplied a contrast that was congruous with either the direct or the indirect object. Experiments 1 and 2 manipulated focus by locating only adjacent to either the direct or indirect object of dative (Experiment 1) or double-object (Experiment 2) sentences. Reading-time effects indicated that the surface position of the focus particle influenced processing. In addition, Experiment 1 reading times were longer when the replacive was incongruous with the constituent that only adjoined, and particle position modulated a similar effect in Experiment 2. Experiment 3 showed that this effect was absent when only was omitted. We conclude that the surface position of a focus particle modulates focus identification during on-line sentence comprehension.
Caffeine Deprivation State Modulates Expression of Acquired Liking for Caffeine-Paired Flavours
Authors: Chambers Lucy , Mobini Sirous , Yeomans Martin R.
Published: September 2007

Previous studies found that caffeine consumers acquired a liking for the flavour of novel caffeinated drinks when these drinks were consumed repeatedly in a caffeine-deprived, but not nondeprived, state. Expression of this acquired liking appeared acutely sensitive to current caffeine deprivation state, but the use of between-subjects designs confounded interpretation of those studies. The present study evaluated these findings further using a within-subject design, with one flavour paired with caffeine (CS +) and the second with the absence of caffeine (CS–). During four CS + and four CS– training days, 32 moderate caffeine consumers alternatively consumed a novel flavoured drink a CS + paired with caffeine and a CS– flavour paired with placebo. Participants evaluated both drinks before and after training in two motivational states: caffeine deprived and nondeprived. As predicted, pleasantness ratings for the caffeine-paired flavour increased overall. However, this acquired liking was only significant when tested in a caffeine-deprived state. These data are consistent with a conditioned-flavour preference model and imply that expression of acquired liking for a novel caffeinated flavour depends on the need for the effects of caffeine at the time when the drink is evaluated.
Attention Dependency in Implicit Learning of Repeated Search Context
Authors: Rausei Valeria , Makovski Tal , Jiang Yuhong V.
Published: September 2007

How much attention is needed to produce implicit learning? Previous studies have found inconsistent results, with some implicit learning tasks requiring virtually no attention while others rely on attention. In this study we examine the degree of attentional dependency in implicit learning of repeated visual search context. Observers searched for a target among distractors that were either highly similar to the target or dissimilar to the target. We found that the size of contextual cueing was comparable from repetition of the two types of distractors, even though attention dwelled much longer on distractors highly similar to the target. We suggest that beyond a minimal amount, further increase in attentional dwell time does not contribute significantly to implicit learning of repeated search context.
Differential Acquisition, Extinction, and Reinstatement of Conditioned Suppression in Mice
Authors: Dirikx Trinette , Beckers Tom , Muyls Clara , Eelen Paul , Vansteenwegen Debora , Hermans Dirk , D'hooge Rudi
Published: September 2007

In animals, the reappearance of conditioned fear responses after extinction has been primarily investigated using single-cue conditioning paradigms. However, a differential paradigm can overcome several of the disadvantages associated with a single-cue procedure. In the present study, the reinstatement phenomenon was assessed in mice using a differential conditioned suppression paradigm. In a first phase, one conditioned stimulus (CS +) was consistently paired with an unconditioned stimulus (US; footshock) while another CS (CS–) was not, resulting in selective suppression of previously trained instrumental behaviour during the CS +. After the extinction phase, half of the animals (reinstatement group) were presented with unsignalled USs, while the other half were not (control group). A differential return of conditioned responding was observed in the reinstatement group, but not in the control group. The implications of these findings for future conditioning research are discussed.
Catching Dreams: Editing Film Scores for Publication
Authors: Winters Ben
Published: September 2007

There is a need for published film-score editions in film musicology, both to preserve the contents of manuscripts and to aid critical readings of films. How to accomplish this, without re-inscribing the Romantic conceptions of authorship commonly associated with edition creation, is the subject of this article. After considering the relevant editorial problems and models, a postmodern ‘anti-edition’ is proposed, using examples drawn from Korngold's score forThe Adventures of Robin Hood(1938).
Searching for the Plot: Charles-Valentin Alkan'sSouvenirs: Trois morceaux dans le genre pathétique, Op. 15
Authors: Waeber Jacqueline
Published: September 2007

In the early nineteenth century, the piano étude was conceived as an outgrowth of the eighteenth-centuryexercice, perpetuating the idea of mechanical virtuosity devoid of any poetic meaning; but it was also shaped by the Romanticpièce de caractère.Drawing upon the context of Parisian musical life in the 1830s (notably the reception of Beethoven's Seventh Symphony), this article discusses Charles-Valentin Alkan's piano étudesSouvenirs: Trois morceaux dans le genre pathétique, op. 15 (Paris, 1837). This work shows how virtuoso idiomatic figures can act as genre markers, thereby allowing the encoding of a specific extramusical meaning. It further addresses the issue of the privileged understanding between the composer and his performer that goes back to eighteenth-century tradition.
Managing Nitrogen and Sulfur Fertilization for Improved Bread Wheat Quality in Humid Environments
Authors: Thomason W. E. , Phillips S. B. , Pridgen T. H. , Kenner J. C. , Griffey C. A. , Beahm B. R. , Seabourn B. W.
Published: September 2007

A large proportion of the wheat (Triticum aestivum L.) milled and utilized by bakeries in the eastern United States is hard red winter wheat (HRWW). Potential for producing this higher value commodity in the eastern United States is dependent on availability of adapted HRWW cultivars that are competitive with soft red winter wheat (SRWW) cultivars and implementation of management systems to enhance end‐use quality. The effects of late‐season nitrogen (N) (0–45 kg of N/ha) applied at two growth stages (GS 45 and 54) and sulfur (S) (0–34 kg of S/ha) applied at GS 30 on grain, flour, and milling and breadbaking quality were evaluated. Three diverse wheat cultivars (Soissons, Heyne, and Renwood 3260) were studied in two to five environments. Application of S and late‐season N had little effect on grain yield. But N consistently increased grain and flour protein as well as bread loaf volume. The magnitude and significance of response to N and S varied by location and cultivar. While S alone did not have a significant effect on grain protein, S availability was critical in obtaining increased grain protein. Breadbaking quality of HRWW cultivars produced in the eastern United States can be improved through implementation of nutrient management approaches that include late‐season application of 34–45 kg of N/ha and addition of S, particularly on sandy soils where S availability in the subsoil is low.
Virulence Genes and the Evolution of Host Specificity in Plant-Pathogenic Fungi
Authors: van der Does H. Charlotte , Rep Martijn
Published: September 2007

In the fungal kingdom, the ability to cause disease in plants appears to have arisen multiple times during evolution. In many cases, the ability to infect particular plant species depends on specific genes that distinguish virulent fungi from their sometimes closely related nonvirulent relatives. These genes encode host-determining “virulence factors,” including small, secreted proteins and enzymes involved in the synthesis of toxins. These virulence factors typically are involved in evolutionary arms races between plants and pathogens. We briefly summarize current knowledge of these virulence factors from several fungal species in terms of function, phylogenetic distribution, sequence variation, and genomic location. Second, we address some issues that are relevant to the evolution of virulence in fungi toward plants; in particular, horizontal gene transfer and the genomic organization of virulence genes.
Functional Analysis of the Metallothionein Gene cgMT1 Isolated from the Actinorhizal Tree Casuarina glauca
Authors: Obertello Mariana , Wall Luis , Laplaze Laurent , Nicole Michel , Auguy Florence , Gherbi Hassen , Bogusz Didier , Franche Claudine
Published: September 2007

cgMT1 is a metallothionein (MT)-like gene that was isolated from a cDNA library of young nitrogen-fixing nodules resulting from the symbiotic interaction between Frankia spp. and the actinorhizal tree Casuarina glauca. cgMT1 is highly transcribed in the lateral roots and nitrogen-fixing cells of actinorhizal nodules; it encodes a class I type 1 MT. To obtain insight into the function of cgMT1, we studied factors regulating the expression of the MT promoter region (PcgMT1) using a β-glucuronidase (gus) fusion approach in transgenic plants of Arabidopsis thaliana. We found that copper, zinc, and cadmium ions had no significant effect on the regulation of PcgMT1-gus expression whereas wounding and H2O2 treatments led to an increase in reporter gene activity in transgenic leaves. Strong PcgMT1-gus expression also was observed when transgenic plants were inoculated with a virulent strain of the bacterial pathogen Xanthomonas campestris pv. campestris. Transgenic Arabidopsis plants expressing cgMT1 under the control of the constitutive 35S promoter were characterized by reduced accumulation of H2O2 when leaves were wounded and by increased susceptibility to the bacterial pathogen X. campestris. These results suggest that cgMT1 could play a role during the oxidative response linked to biotic and abiotic stresses.
Molecular Characterization of Naturally Occurring RNA1 Recombinants of the Comovirus Bean pod mottle virus
Authors: Zhang Chunquan , Gu Hongcang , Ghabrial Said A.
Published: September 2007

The Bean pod mottle virus, a member of the genus Comovirus, has a bipartite genome consisting of RNA1 and RNA2. We previously reported the occurrence in nature of two distinct subgroups of BPMV strains (subgroups I and II), as well as reassortants between the two subgroups. Here, we report on the isolation and molecular characterization of RNA1 recombinants from soybean plants infected with the partial diploid reassortant strain IL-Cb1, which induces very severe symptoms on soybean. cDNA cloning and sequencing of RNA1 from strain IL-Cb1 revealed the presence of chimeric and mosaic recombinant RNA1s. The full-length mosaic and chimeric recombinant RNA1s were infectious and induced mild symptoms on soybean. Although the recombinant RNA1 accumulated to high levels in the absence of wild-type RNA1, its accumulation level was low in mixed infections with wild-type RNA1. Recombinant RNA1 molecules with similar structures to the naturally occurring recombinant RNA1s were generated in soybean after four passages following inoculation with RNA1 transcripts derived from cDNAs of two distinct strains. This suggests that recombination events are frequent and that a recombination hot spot exists. Sequence analysis of the recombination region showed that it has AU-rich sequences characteristic of recombination hot spots.
Dispersal Distances for Airborne Spores Based on Deposition Rates and Stochastic Modeling
Authors: Stockmarr Anders , Andreasen Viggo , Østergård Hanne
Published: September 2007

A new modeling framework for particle dispersal is explored in the context of the particles being fungal spores dispersed within a field. The model gives rise to both exponentially decreasing and polynomially decreasing two-dimensional densities of deposited fungal spores. We reformulate the model in terms of time to deposition, and show how this concept is equivalent to the deposition rate for fungal spores. Special cases where parameter values for wind and gravitation lead to exponentially or polynomially decreasing densities are discussed, and formulas for one- and two-dimensional densities of deposited spores are given explicitly in terms of parameters for diffusion, wind, gravitation, and spore release height.
Area summation in human vision at and above detection threshold
Authors: Meese Tim S , Summers Robert J
Published: September 2007

The initial image-processing stages of visual cortex are well suited to a local (patchwise) analysis of the viewed scene. But the world's structures extend over space as textures and surfaces, suggesting the need for spatial integration. Most models of contrast vision fall shy of this process because (i) the weak area summation at detection threshold is attributed to probability summation (PS) and (ii) there is little or no advantage of area well above threshold. Both of these views are challenged here. First, it is shown that results at threshold are consistent with linear summation of contrast following retinal inhomogeneity, spatial filtering, nonlinear contrast transduction and multiple sources of additive Gaussian noise. We suggest that the suprathreshold loss of the area advantage in previous studies is due to a concomitant increase in suppression from the pedestal. To overcome this confound, a novel stimulus class is designed where: (i) the observer operates on a constant retinal area, (ii) the target area is controlled within this summation field, and (iii) the pedestal is fixed in size. Using this arrangement, substantial summation is found along the entire masking function, including the region of facilitation. Our analysis shows that PS and uncertainty cannot account for the results, and that suprathreshold summation of contrast extends over at least seven target cycles of grating.
Characterization of the epitope for anti-human respiratory syncytial virus F protein monoclonal antibody 101F using synthetic peptides and genetic approaches
Authors: Wu Sheng-Jiun , Schmidt Albert , Beil Eric J. , Day Nicole D. , Branigan Patrick J. , Liu Changbao , Gutshall Lester L. , Palomo Concepción , Furze Julie , Taylor Geraldine , Melero José A. , Tsui Ping , Del Vecchio Alfred M. , Kruszynski Marian
Published: September 2007

Chimeric 101F (ch101F) is a mouse–human chimeric anti-human respiratory syncytial virus (HRSV) neutralizing antibody that recognizes residues within antigenic site IV, V, VI of the fusion (F) glycoprotein. The binding of ch101F to a series of peptides overlapping aa 422–438 spanning antigenic site IV, V, VI was analysed. Residues 423–436 comprise the minimal peptide sequence for ch101F binding. Substitution analysis revealed that R429 and K433 are critical for ch101F binding, whilst K427 makes a minor contribution. Binding of ch101F to a series of single mutations at positions 427, 429 and 433 in the F protein expressed recombinantly on the cell surface confirmed the peptide results. Sequence analysis of viruses selected for resistance to neutralization by ch101F indicated that a single change (K433T) in the F protein allowed ch101F escape. The results confirm that ch101F and palivizumab have different epitope specificity and define key residues for ch101F recognition.
Comparative analysis of innate immune responses following infection of newborn calves with bovine rotavirus and bovine coronavirus
Authors: Aich Palok , Wilson Heather L. , Kaushik Radhey S. , Potter Andy A. , Babiuk Lorne A. , Griebel Philip
Published: September 2007

Bovine rotavirus (BRV) and bovine coronavirus (BCV) are important causes of diarrhoea and death in newborn calves. Although these viruses belong to distinct viral classes, they both infect intestinal epithelial cells and induce similar clinical symptoms. Rotavirus usually causes an acute infection, but coronavirus infection can persist and reoccur in adults. Differences in viral structure and clinical outcome prompted us to postulate that innate mucosal immune responses would be markedly different following rotavirus and coronavirus infections. To address this hypothesis, gene expression following BRV and BCV infection was analysed in surgically prepared intestinal loops from 1-day-old colostrum-deprived calves. Gene expression was profiled at 18 h post-infection using bovine cDNA microarrays; the majority of differentially expressed significant genes were associated with the cell cycle and innate immune responses. A select group of these genes was validated by quantitative real-time PCR (qRT-PCR). The expression of genes associated with interferons (IFNs), cytokines and Toll-like receptors, which were not present on the microarray, was analysed further by qRT-PCR. Strong activation of TLR3, IL-6 and p65 was observed in BRV-infected host tissues, but not in tissues infected with BCV. Both viruses also downregulated IFN- and pro-inflammatory cytokine-associated pathways.In vitrostudies confirmed that IFN inhibited viral replication. All of these results together suggested either that very early events of host responses at 18 h post-infection were being observed, or that both viruses have unique effective strategies to evade host immune responses.
Genetic diversity of cutaneous human papillomaviruses
Authors: Forslund Ola
Published: September 2007

Human papillomaviruses (HPVs) of the generaBetapapillomavirusandGammapapillomavirusare common on human skin. Sequencing of subgenomic amplicons of cutaneous HPVs has revealed a large number of novel putative HPV types within these genera. Phylogenetic analysis based on these amplicons revealed 133 putative HPV types with <90 % sequence identity to any known HPV type or to each other. As there are already 34 characterized HPV types described within the generaBetapapillomavirusandGammapapillomavirus, they appear to be the most genetically diverse of the HPVs, apparently comprising at least 167 different HPV types.