bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictive condition‐based maintenance for continuously deteriorating systems
Authors: Lu Susan , Tu Yu‐Chen , Lu Huitian
Published: January 2007

This paper addresses a predictive condition‐based maintenance approach based on monitoring, modeling, and predicting a system's deterioration. The system's deterioration is considered as a stochastic dynamic process with continuous degrading. Structural time series, coupled with state‐space modeling and Kalman filtering methods, is adopted for recursively modeling and forecasting the deterioration state at a future time. The probability of a failure is then predicted based on the forecasted deterioration state and a threshold of a failure. Finally, maintenance decisions are made according to the predicted failure probabilities, associated preventive and corrective maintenance cost, and the profit loss due to system performance deterioration. The approach can be applied on‐line to provide economic and preventive maintenance solutions in order to maximize the profit of the ownership of a system. Copyright © 2007 John Wiley & Sons, Ltd.
Desorption electrospray ionisation mass spectrometric analysis of chemical warfare agents from solid‐phase microextraction fibers
Authors: D'Agostino Paul A. , Chenier Claude L. , Hancock James R. , Lepage Carmela R. Jackson
Published: January 2007

Desorption electrospray ionisation mass spectrometry (DESI‐MS) was recently reported for the direct analysis of sample media without the need for additional sample handling. During the present study, direct analysis of solid‐phase microextraction (SPME) fibers by DESI‐MS/MS was evaluated with indoor office media that might be collected during a forensic investigation, including wall surfaces, office fabrics, paper products and Dacron swabs used for liquid sampling. Media spiked at the µg/g level with purified chemical warfare agents and a complex munitions grade sample of tabun, to simulate the quality of chemical warfare agent that might be used for terrorist purposes, were successfully analysed by DESI‐MS/MS. Sulfur mustard, a compound that has not been successfully analysed by electrospray mass spectrometry in the past, was also sampled using a SPME fiber and analysed for the first time by DESI‐MS/MS. Finally, the overall analytical approach involving SPME headspace sampling and DESI‐MS analysis was evaluated during a scenario‐based training live agent exercise. A sarin sample collected by the military was analysed and confirmed by DESI‐MS in a mobile laboratory under realistic field conditions. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Statistical power of multiplicity adjustment strategies for correlated binary endpoints
Authors: Leon Andrew C. , Heo Moonseong , Teres Jedediah J. , Morikawa Toshihiko
Published: January 2007

There are numerous alternatives to the so‐called Bonferroni adjustment to control for familywise Type I error among multiple tests. Yet, for the most part, these approaches disregard the correlation among endpoints. This can prove to be a conservative hypothesis testing strategy if the null hypothesis is false. The James procedure was proposed to account for the correlation structure among multiple continuous endpoints. Here, a simulation study evaluates the statistical power of the Hochberg and James adjustment strategies relative to that of the Bonferroni approach when used for multiple correlated binary variables. The simulations demonstrate that relative to the Bonferroni approach, neither alternative sacrifices power. The Hochberg approach has more statistical power for ρ⩽0.50; whereas the James procedure provides more statistical power with higher ρ, the common correlation among the multiple outcomes. A study of gender differences in New York City homicides is used to illustrate the approaches. Copyright © 2007 John Wiley & Sons, Ltd.
Learning to develop the relationship between research and teaching at an institutional level
Authors: Brew Angela
Published: January 2007

When implementing institutional strategies to bring research and teaching together, learning occurs. A research‐intensive university in Australia put in place institutional strategies to strengthen the relationship between research and teaching.
Disciplines, pedagogy, and inquiry‐based learning about teaching
Authors: Huber Mary Taylor
Published: January 2007

The disciplines contribute in a variety of ways to inquiry‐based learning about teaching but they also can be seen as the beneficiaries of such pedagogical work.
Exploring methodological issues related to pedagogical inquiry in higher education
Authors: D'Andrea Vaneeta‐marie
Published: January 2007

Pedagogical inquiry on teaching and learning in higher education is best served by methodological approaches that produce purposeful questions and engage in systematic analysis.
RNA interference‐mediated silencing of the bursicon gene induces defects in wing expansion of silkworm
Authors: Huang Jianhua , Zhang Yong , Li Minghui , Wang Sibao , Liu Wenbin , Couble Pierre , Zhao Guoping , Huang Yongping
Published: January 2007

We studied the role of the bursicon gene in wing expansion. First, we investigated its expression at different developmental stages in the silkworm, Bombyx mori. Bursicon gene was expressed at low levels in larvae, high levels in pupae, and low levels again in adults. Then, we injected the double‐stranded bursicon RNA into B. mori pupae to test RNA interference. The level of bursicon mRNA was reduced significantly in pupae, and a deficit in wing expansion was observed in adults. In addition, the differential display reverse transcription polymerase chain reaction (DD‐RT‐PCR) was used to reveal differences in the expression of transcripts in response to the inhibition of bursicon. In conclusion, bursicon plays a key role in the stereotyped behavioral program involved in wing expansion.
Involvement of membrane protein GDE2 in retinoic acid‐induced neurite formation in Neuro2A cells
Authors: Yanaka Noriyuki , Nogusa Yoshihito , Fujioka Yuichiro , Yamashita Yosuke , Kato Norihisa
Published: January 2007

We show that a glycerophosphodiester phosphodiesterase homolog, GDE2, is widely expressed in brain tissues including primary neurons, and that the expression of GDE2 in neuroblastoma Neuro2A cells is significantly upregulated during neuronal differentiation by retinoic acid (RA) treatment. Stable expression of GDE2 resulted in neurite formation in the absence of RA, and GDE2 accumulated at the regions of perinuclear and growth cones in Neuro2A cells. Furthermore, a loss‐of‐function of GDE2 in Neuro2A cells by RNAi blocked RA‐induced neurite formation. These results demonstrate that GDE2 expression during neuronal differentiation plays an important role for growing neurites.
DIFFUSIVE TRANSPORT OF PARTIALLY QUANTIZED PARTICLES: EXISTENCE, UNIQUENESS AND LONG-TIME BEHAVIOUR
Authors: Ben Abdallah N. , Méhats F. , Vauchelet N.
Published: January 2007

A self-consistent model for charged particles, accounting for quantum confinement, diffusive transport and electrostatic interaction is considered. The electrostatic potential is a solution of a three-dimensional Poisson equation with the particle density as the source term. This density is the product of a two-dimensional surface density and that of a one-dimensional mixed quantum state. The surface density is the solution of a drift–diffusion equation with an effective surface potential deduced from the fully three-dimensional one and which involves the diagonalization of a one-dimensional Schrödinger operator. The overall problem is viewed as a two-dimensional drift–diffusion equation coupled to a Schrödinger–Poisson system. The latter is proven to be well posed by a convex minimization technique. A relative entropy and an a priori $L^2$ estimate provide sufficient bounds to prove existence and uniqueness of a global-in-time solution. In the case of thermodynamic equilibrium boundary data, a unique stationary solution is proven to exist. The relative entropy allows us to prove the convergence of the transient solution towards it as time grows to infinity. Finally, the low-order approximation of the relative entropy is used to prove that this convergence is exponential in time.
THE FACTORIZABLE BRAID MONOID
Authors: East James
Published: January 2007

In this paper we study the factorizable braid monoid (also known as the merge-and-part braid monoid) introduced by Easdown, East and FitzGerald in 2004. We find several presentations of this monoid, and uncover an interesting connection with the singular braid monoid. This leads to the definition of the flexible singular braid monoid, which consists of ‘flexible-vertex-isotopy’ classes of singular braids. We conclude by defining and studying the pure factorizable braid monoid, the maximal subgroups of which are (isomorphic to) quotients of the pure braid group.
THE EXISTENCE OF ISOTROPIC MODULI SPACES
Authors: Showkat Ali Md.
Published: January 2007

A theorem on the existence of moduli spaces of compact complex isotropic submanifolds in complex contact manifolds is established.
NONLINEAR NON-LOCAL BOUNDARY-VALUE PROBLEMS AND PERTURBED HAMMERSTEIN INTEGRAL EQUATIONS
Authors: Infante Gennaro , Webb J. R. L.
Published: January 2007

Motivated by some non-local boundary-value problems (BVPs) that arise in heat-flow problems, we establish new results for the existence of non-zero solutions of integral equations of the form

$$ u(t)=\gamma(t)\alpha[u]+\int_{G}k(t,s)f(s,u(s))\,\mathrm{d}s, $$

where $G$ is a compact set in $\mathbb{R}^{n}$. Here $\alpha[u]$ is a positive functional and $f$ is positive, while $k$ and $\gamma$ may change sign, so positive solutions need not exist. We prove the existence of multiple non-zero solutions of the BVPs under suitable conditions. We show that solutions of the BVPs lose positivity as a parameter decreases. For a certain parameter range not all solutions can be positive, but for one of the boundary conditions we consider we show that there are positive solutions for certain types of nonlinearity. We also prove a uniqueness result.
THE BOUSFIELD–KAN SPECTRAL SEQUENCE FOR MORAVA $K$-THEORY
Authors: La Luz José
Published: January 2007

We construct a spectral sequence converging to the $E_{2}$-term of the Bousfield–Kan spectral sequence (BKSS) for a wide variety of homology theories. Using this, the $E_{2}$-term of the BKSS based on $K(1)$-theory for the odd spheres is computed and the unstable $K(1)$-completion is computed.
PAPER PRESENTED AT INTERNATIONAL WORKSHOP ON INCREASING WHEAT YIELD POTENTIAL, CIMMYT, OBREGON, MEXICO, 20–24 MARCH 2006 Genetic progress in yield potential in wheat: recent advances and future prospects
Authors: FOULKES M. J. , SNAPE J. W. , SHEARMAN V. J. , REYNOLDS M. P. , GAJU O. , SYLVESTER-BRADLEY R.
Published: January 2007

Knowledge of the changes in physiological traits associated with genetic gains in yield potential is essential to improve understanding of yield-limiting factors and to inform future breeding strategies. Recent advances in genetic yield potential and associated physiological changes in wheat (Triticum aestivum L.) are reviewed. Genetic gains in yield potential worldwide have been both positively correlated with harvest index (HI) and above-ground dry matter (AGDM), with more frequent reports of yield progress associated with biomass since about 1990. It is concluded that an important aim of future breeding will be the increase of biomass production while maintaining the present values of HI. In winter wheat recent biomass progress has been positively associated with pre-anthesis radiation-use efficiency (RUE) and water-soluble carbohydrate (WSC) content of stems at anthesis. Present results in two doubled-haploid (DH) populations show a positive linear relationship between stem WSC and grain yield in the UK environment. Results from various investigations worldwide in recent years have demonstrated that biomass increases have been associated with particular introductions of alien genes into wheat germplasm, e.g. the 1BL.1RS wheat-rye translocation and the 7DL.7Ag wheat-Agropyron elongatum translocation. Present results confirm a positive effect of 1BL.1RS on harvest biomass in two DH populations in the UK. The future prospects for identifying physiological traits to raise yield potential are considered with particular reference to winter wheat grown in northwestern Europe. It is proposed that optimized rooting traits, an extended stem-elongation phase, greater RUE, greater stem WSC storage and optimized ear morphology will be important for breeding progress in yield potential in future years.
Different surgical treatments for nasal septal perforation and their outcomes
Authors: Goh A Y , Hussain S S M
Published: January 2007

Objective: To critically evaluate the literature on surgical treatment options for nasal septal perforations and to analyse the outcomes of these treatment options.

Design: A systematic review of studies of nasal septal perforation closure using surgical intervention, published from January 1975 to March 2006.

Data sources: Forty-nine papers were identified from electronic databases (all Evidence Based Medicine reviews (Cochrane Database of Systematic Reviews, American College of Physicians Journal Club, Database of Abstracts of Reviews of Effectiveness and Cochrane Controlled Trials Register), EMBASE, Ovid (Medline) and British Medical Journal publications) and from a hand search of the reference lists of retrieved papers. Textbooks pertinent to the subject were referred to for background reading. Twenty-three studies met the inclusion criteria.

Main outcome measure: Effectiveness of the surgical intervention to completely close the perforation.

Results: Five studies examined the sole use of intranasal mucosal flaps to close the perforation, i.e. inferior turbinate flaps, quadrangular cartilage flap and mucoperiosteal flap. Eighteen studies reported the use of a combination of intranasal mucosal flap and interposition graft. Graft materials included temporalis fascia, mastoid periosteum, nasal septal material, acellular human dermal graft, conchal cartilage and porcine small intestine mucosa. Studies utilising interposition grafts generally produced higher closure rates. The surgical approaches documented include closed endonasal, unilateral hemitransfixion, external rhinoplasty and midfacial degloving techniques. A range of surgical treatment methods was reported in the literature, but some papers were excluded from this review as they did not meet the inclusion criteria. It was difficult to infer the true effectiveness of each study as the subject numbers were small, patient selection criteria were often unspecified and the follow-up period was brief. However, factors leading to an increased chance of success were identified.

Conclusion: The review found an extensive range of surgical treatment techniques, but reported results were rarely statistically significant. It is difficult to be categorical about the effectiveness of a surgical treatment method; nonetheless, each technique has its own advantages and drawbacks.
Paediatric granular cell tumour of the larynx: case report of laser resection with frozen section
Authors: Holton C , Cruickshank H E , High A S , Maclennan K , Makura Z G G
Published: January 2007

Granular cell tumours of the larynx are a very rare cause of persistent hoarse or husky voice in children. We report the case of a 13-year-old girl who presented with a three-year history of progressively huskier voice. We discuss the presentation, location and diagnosis of the tumour. In addition, we present a method of surgical treatment of the tumour, involving the hitherto unreported technique of laser excision and frozen section of the lesion.
The orders of creation in the theological ethics of Karl Barth
Authors: Nimmo Paul T.
Published: January 2007

It is widely known that early on in his teaching career Karl Barth advanced a concept of the ‘orders of creation’, but that he retracted that concept in his later work in reaction to the tragic use that had been made of it by the National Socialist movement in Germany. However, two aspects of this movement remain relatively unexplored: first, the underlying material continuity between Barth's early ethics and his later ethics that this movement occludes; and second, the significant methodological shift in Barth's theology which this movement attests. This article explores both these aspects of Barth's theological development through his treatment of the ‘orders of creation’.
The extent to which the rise in the worship of images in the late Middle Ages was influenced by contemporary theories of vision
Authors: Joby Christopher
Published: January 2007

There are several ways whereby medieval theories of vision may have contributed to the rise of practices some saw as idolatrous. A feature of much medieval art is the rise of naturalistic representation. This process was facilitated by the use of linear perspective, based ultimately on Euclid's visual cone. We are told its application led viewers to confuse a representation with its object. The theory of extramission influenced medieval piety profoundly. First, by suggesting that the eye emits a ray and ‘touches’ its object, it led worshippers to believe that seeing the Eucharistic host had a salvific effect. This may have led them to think that seeing images of saints or God had a similar effect. Second, by implying that the subject was active in the process of seeing, it underpinned Augustine's theory of vision, whereby one trained the eye to access the invisible through the visible. However, as he was aware, the untrained eye could linger on physical objects and want to possess them. Finally, there was much debate about how visual information was mediated. Some argued that it was transmitted by intermediate bodies. The parallels between their language and that used by iconophobes to describe the images they rejected are striking and merit further investigation. Others argued that the viewer had direct access to the object. This understanding, when combined with the idea that seeing equates to knowing, may have led worshippers to believe that seeing an image of God meant they might in some sense know him.
Karl Barth on the Eternal Existence of Jesus Christ
Authors: van Driel Edwin Chr.
Published: January 2007

Central to Barth's doctrine of election is the notion that Jesus Christ is the subject of election. This implies that Jesus Christ existed from all eternity. I discuss four possible interpretations of this proposition. I analyse these interpretations both in terms of their internal consistency and in terms of their consistency with Barth's overall proposal. Three of the four interpretations, defended by Emil Brunner, Cornelius Berkouwer, John Colwell and Bruce McCormack, I find wanting. With the fourth interpretation I lay my own cards on the table and argue that part of the problem lies in Barth's formulation itself. The context of Barth's saying that ‘Christ is the subject of election’ suggests that for Barth, Jesus Christ is not so much identical not with a subject, but with an act: the divine reaching out to that what is not God. This act establishes the act and object of election.
David Hart, The Beauty of the Infinite: A Response
Authors: Murphy Francesca
Published: January 2007

I dissent from Hart's project of a theological aesthetics by a hair's breadth: but that hair's breadth is tragedy. The Beauty of the Infinite is an excellent book, but it would be still better without its misinterpretations of tragedy. Nietzsche told us that ‘we must understand Greek tragedy as the Dionysian chorus which ever anew discharges itself in an Apollonian world of images’: that is, Attic tragedy arises from the clash of Dionysian music with Apollonian thought. Hart regards postmodernism as a story involving the clash of two ‘violences’ – the ‘chthonic and indiscriminate’ violence of Dionysus versus the ‘discriminating’ violence of Apollo. Nietzsche's sympathies lay with Dionysus: ‘Dionysus versus the “Crucified”: there you have the antithesis.’ Nietzsche once confessed that The Birth of Tragedy ‘smells offensively Hegelian’. Both Hegel and Nietzsche read tragedy differently from Aristotle, and from the anterior Western tradition. Nietzsche could equally have confided that his first book imposes a nineteenth-century taste for melodrama on the tragedies of Aeschylus and Sophocles. The argument of this article is that Hart likewise misconstrues tragedy as melodrama. If, as Hart says, ‘Nietzsche had atrocious taste’, it is self-defeating for him to assume that Nietzsche had the last word on Sophocles, Aeschylus and Euripides. Hart takes the modern theologians at their word when they speak of ‘tragedy’. He spontaneously deprecates the use of what he calls tragedy and what most people can recognize as melodrama in the writings of theologians such as Robert Jenson, Donald MacKinnon and Nicholas Lash. He tells us that, ‘None of what I say … is intended as a rejection of tragedy as such … but only as a critique … of the sacrificial logic from which Attic tragedy … sprang and according to which … tragedy is still read’. But his misinterpretation and rejection of tragedy has a wider reference than the writings of Sophocles and Aeschylus and rebounds on his own theology.
Reduction in syllable onsets in the acquisition of Polish: deletion, coalescence, metathesis and gemination
Authors: ŁUKASZEWICZ BEATA
Published: January 2007

This paper focuses on four strategies of onset reduction employed by a single child (4;0–4;4) acquiring Polish: deletion, coalescence, metathesis, and gemination. Deletion and coalescence occur in word-initial onsets while metathesis and gemination are restricted to word-medial position. The data, which constitute an intriguing ‘conspiracy’ case (Kisseberth, 1970), are analysed within OPTIMALITY THEORY (henceforth, OT; Prince & Smolensky, 1993/2004; McCarthy & Prince, 1995) in which all surface-true ‘processes’ are motivated through the interaction of ranked and violable constraints. The OT account makes it possible to envisage the four strategies as different surface responses to the undominated *COMPLEXOnset which militates against onset clusters. The choice of a particular strategy as well as its restriction to a particular word position is not random but follows from the interplay between *COMPLEXOnset, sonority-based syllable structure constraints (Margin Hierarchy, CONTACT LAW), context-sensitive markedness constraints (CODA CONDITION, *Nasal–Fricative) and faithfulness constraints. The present study confirms previous sonority-based findings, supplies further evidence for universal sonority mechanisms from word-medial clusters, and points to the coexistence of child-specific and abstract adult-based phonological strategies in the child’s system.
Efficient Cellulase Production by the Filamentous Fungus Acremonium cellulolyticus
Authors: Ikeda Yuko , Hayashi Hiroyuki , Okuda Naoyuki , Park Enock Y.
Published: January 2007

Cellulase production was investigated in a culture of a strain of Acremonium cellulolyticus. The medium components were optimized for the improvement of cellulase production. The maximum production of cellulolytic enzymes was obtained in a medium containing (grams per liter) 50 Solka Floc, 5 (NH4)2SO4, 24 KH2PO4, 4.7 potassium tartrate hemihydrate, 1.2 MgSO4·7H2O, 1 Tween 80, 4 urea, 0.01 ZnSO4·7H2O, 0.01 MnSO4·6H2O, and 0.01 CuSO4·7H2O, with a pH of 4.0. In the flask culture, 15.5 filter paper units (FPU)/mL of maximum cellulase activity was obtained, 17.42 FPU/mL in a 7‐L bioreactor, and 13.08 FPU/mL in a 50‐L scale bioreactor for 4–8 d at 30 °C. Average production rates were 1.94 FPU/mL·d in flasks, 2.86 FPU/mL·d in the 7‐L bioreactor, and 2.56 FPU/mL·d in the 50‐L bioreactor. Cellulase production on a small scale was successfully reproduced in the 50‐L pilot scale bioreactor. Saccharification activity from A. cellulolyticus was compared with cellulolytic enzymes produced by other strains. The A. cellulolyticus culture broth had a comparable saccharification yield in comparison with those of other Trichoderma enzymes (GC220 or Cellulosin T2) under the same total cellulase activity. Its saccharification yield (percent of released reducing sugar to used dried substrate) was 60%, and its glucose content was 83%.
Effect of Different Carbon Sources on the Production of Succinic Acid Using Metabolically Engineered Escherichia coli
Authors: Andersson Christian , Hodge David , Berglund Kris A. , Rova Ulrika
Published: January 2007

Succinic acid (SA) is an important platform molecule in the synthesis of a number of commodity and specialty chemicals. In the present work, dual‐phase batch fermentations with the E. coli strain AFP184 were performed using a medium suited for large‐scale industrial production of SA. The ability of the strain to ferment different sugars was investigated. The sugars studied were sucrose, glucose, fructose, xylose, and equal mixtures of glucose and fructose and glucose and xylose at a total initial sugar concentration of 100 g L−1. AFP184 was able to utilize all sugars and sugar combinations except sucrose for biomass generation and succinate production. For sucrose as a substrate no succinic acid was produced and none of the sucrose was metabolized. The succinic acid yield from glucose (0.83 g succinic acid per gram glucose consumed anaerobically) was higher than the yield from fructose (0.66 g g−1). When using xylose as a carbon source, a yield of 0.50 g g−1 was obtained. In the mixed‐sugar fermentations no catabolite repression was detected. Mixtures of glucose and xylose resulted in higher yields (0.60 g g−1) than use of xylose alone. Fermenting glucose mixed with fructose gave a lower yield (0.58 g g−1) than fructose used as the sole carbon source. The reason is an increased pyruvate production. The pyruvate concentration decreased later in the fermentation. Final succinic acid concentrations were in the range of 25–40 g L−1. Acetic and pyruvic acid were the only other products detected and accumulated to concentrations of 2.7–6.7 and 0–2.7 g L−1. Production of succinic acid decreased when organic acid concentrations reached approximately 30 g L−1. This study demonstrates that E. coli strain AFP184 is able to produce succinic acid in a low cost medium from a variety of sugars with only small amounts of byproducts formed.
Prediction and analysis of long‐term variability of temperature and salinity in the Irish Sea
Authors: Young E. F. , Holt J. T.
Published: January 2007

The variability of temperature and salinity in the Irish Sea over the 40 year period 1960–1999 is investigated using a free‐running fine‐resolution local area model. The skill of the model to represent observed temperature and salinity variability is assessed using conductivity‐temperature‐depth survey data (3397 profiles) and a long time series of measurements from Cypris station (southwest of Isle of Man). This clearly demonstrates that the model can reproduce the observed seasonal and longer‐term cycles in temperature, with mean and RMS errors of −0.01°C and 0.78°C. Particularly apparent is the long‐term warming trend at Cypris station and throughout the model domain. Model estimates of salinity are less accurate and are generally too saline (mean and RMS errors are 0.79 and 0.98 practical salinity units). Inaccuracies are likely to arise from boundary conditions and forcing (riverine and surface). However, while absolute values are not particularly well represented, the model reproduces many of the trends in the salinity variability observed at Cypris station, suggesting that the dominant physical processes in the Irish Sea, with timescales up to ∼3 years, are well represented. The model is also used to investigate the variability in temperature stratification. While stratification is confined to approximately the same geographical area in each year of the simulation, there is significant variability in the timing of the onset and breakdown of stratification and in the peak surface to bed temperature difference. Together, these results suggest that a local area model with limited boundary conditions may be sufficiently accurate for climatic investigation of some (locally forced) parameters.
Theoretical investigation of the influence of a quasi‐2‐day wave on nonlinear photochemical oscillations in the mesopause region
Authors: Kulikov M. Y.
Published: January 2007

The influence of a quasi‐2‐day atmospheric wave of given amplitude on the 2‐day photochemical oscillations occurring in the mesopause region (heights of 80 to 90 km) in the regime of subharmonic nonlinear response to diurnal variations of solar radiation is investigated. It is revealed that the most significant mechanism is periodic transport of minor gas constituents by the vertical wind associated with the wave. This mechanism may lead to phase locking of photochemical oscillations to wind oscillations and, thereby, to the formation of regular horizontal distribution of minor gas constituents with zonal wave number close to the wave number of the atmospheric wave. The influence on phase locking of two other factors, namely, transport by the zonal mean zonal wind and by the horizontal component of wind of the wave, is also analyzed.
3‐D surface wave tomography of the Piton de la Fournaise volcano using seismic noise correlations
Authors: Brenguier Florent , Shapiro Nikolai M. , Campillo Michel , Nercessian Alexandre , Ferrazzini Valérie
Published: January 2007

We invert Rayleigh waves reconstructed from cross‐correlations of 18 months of ambient seismic noise recorded by permanent seismological stations run by the Piton de la Fournaise Volcanological Observatory. By correlating noise records between 21 receivers, we reconstruct Rayleigh waves with sufficient signal‐to‐noise ratio for 210 inter‐station paths. We use the reconstructed waveforms to measure group velocity dispersion curves at periods between 1.5 and 4.5 s. The obtained measurements are inverted for two‐dimensional group velocity maps and finally for a 3‐D S‐wave velocity model of the edifice from +2 to −1 km above sea level. Our results clearly show a high velocity body spatially delimited by the borders of the active 10 km wide caldera. The preferential N30°‐N130° orientations of this anomaly at −0.5 km below sea‐level is an evidence of the preferential paths of magma injections associated to the NE‐SE Rift Zones. This structure is surrounded by a low‐velocity ring interpreted as effusive products associated to the construction of the Piton de la Fournaise volcano on the flank of the older Piton des Neiges volcano.
Relative paleointensity stack during the last 250 kyr in the northwest Pacific
Authors: Yamamoto Y. , Yamazaki T. , Kanamatsu T. , Ioka N. , Mishima T.
Published: January 2007

We have conducted a paleomagnetic study of 10 sediment cores recovered from the northwest Pacific. The purpose is to establish a regional paleointensity stack during the last 250 kyrs (NOPAPIS‐250) for global coverage of paleointensity data as well as a regional reference for paleointensity‐assisted stratigraphy. In the studied cores, reductive dissolution of magnetite appears to have occurred mainly in glacial periods. Such horizons accompany large decreases in S‐ratio (S−0.3T = (1 − IRM−0.3T/SIRM)/2) as low as 0.90. The sediments are also intercalated by frequent volcanic ash layers. Prerequisites for reliable relative paleointensity estimation are not satisfied at these horizons. We rejected unsuitable data by quantitative criteria based on S‐ratio and saturation isothermal remanent magnetization (SIRM) and constructed the NOPAPIS‐250 curve from the remaining data. In the construction of the curve, we chose IRM as a normalizer because acquisitions of anhysteretic remanent magnetization (ARM) are considered to be influenced by magnetic interactions among magnetic grains in the northwest Pacific sediments. Relative intensity variation of the NOPAPIS‐250 gives a standard deviation that is 33% of the average, if the normal distribution is assumed. The NOPAPIS‐250 curve generally shows similar variation patterns compared with other high‐resolution records reported from other regions: many paleointensity lows are recognized in common. Six out of the nine lows can be correlated with reported excursions in literature.
Performance of satellite‐based navigation for marine users during ionospheric disturbances
Authors: Skone S. , Yousuf R.
Published: January 2007

The Global Positioning System (GPS) is used worldwide for marine navigation in support of hydrographic surveying operations, where horizontal positioning requirements are typically better than 10 m (95%). Differential techniques are used to reduce errors associated with signal propagation through the dispersive ionosphere and to achieve such accuracies. Two such methods are differential GPS (DGPS), in which range corrections are derived for a nearby reference station and are applied at the remote user location, and wide‐area differential GPS (WADGPS), in which ionosphere range errors are modeled over a large area using a sparse network of GPS ground stations. Both DGPS and WADGPS (Wide Area Augmentation Service) positioning accuracies are investigated here, throughout North America, for a severe geomagnetic storm event in 2003. DGPS horizontal positioning errors of 10–15 m (95%) are observed during this event, and WADGPS positioning errors generally exceed those for DGPS. This is attributed to the sparse WADGPS reference network and associated limitations in resolving the severe ionosphere gradients.
Selective recognition of acetylated histones by bromodomains in transcriptional co-activators
Authors: Hassan Ahmed H. , Awad Salma , Al-Natour Zeina , Othman Samah , Mustafa Farah , Rizvi Tahir A.
Published: January 2007

Bromodomains are present in many chromatin-associated proteins such as the SWI/SNF and RSC chromatin remodelling and the SAGA HAT (histone acetyltransferase) complexes, and can bind to acetylated lysine residues in the N-terminal tails of the histones. Lysine acetylation is a histone modification that forms a stable epigenetic mark on chromatin for bromodomain-containing proteins to dock and in turn regulate gene expression. In order to better understand how bromodomains read the ‘histone code’ and interact with acetylated histones, we have tested the interactions of several bromodomains within transcriptional co-activators with differentially acetylated histone tail peptides and HAT-acetylated histones. Using GST (glutathione S-transferase) pull-down assays, we show specificity of binding of some bromodomains to differentially acetylated H3 and H4 peptides as well as HAT-acetylated histones. Our results reveal that the Swi2/Snf2 bromodomain interacts with various acetylated H3 and H4 peptides, whereas the Gcn5 bromodomain interacts only with acetylated H3 peptides and tetra-acetylated H4 peptides. Additionally we show that the Spt7 bromodomain interacts with acetylated H3 peptides weakly, but not with acetylated H4 peptides. Some bromodomains such as the Bdf1-2 do not interact with most of the acetylated peptides tested. Results of the peptide experiments are confirmed with tests of interactions between these bromodomains and HAT-acetylated histones. Furthermore, we demonstrate that the Swi2/Snf2 bromodomain is important for the binding and the remodelling activity of the SWI/SNF complex on hyperacetylated nucleosomes. The selective recognition of the bromodomains observed in the present study accounts for the broad effects of bromodomain-containing proteins observed on binding to histones.
Towards abolition of immunogenic structures in insect cells: characterization of a honey-bee (Apis mellifera) multi-gene family reveals both an allergy-related core α1,3-fucosyltransferase and the first insect Lewis-histo-blood-group-related antigen-synthesizing enzyme
Authors: Rendić Dubravko , Klaudiny Jaroslav , Stemmer Ute , Schmidt Julia , Paschinger Katharina , Wilson Iain B. H.
Published: January 2007

Glycoproteins from honey-bee (Apis mellifera), such as phospholipase A2 and hyaluronidase, are well-known major bee-venom allergens. They carry N-linked oligosaccharide structures with two types of α1,3-fucosylation: the modification by α1,3-fucose of the innermost core GlcNAc, which constitutes an epitope recognized by IgE from some bee-venom-allergic patients, and an antennal Lewis-like GalNAcβ1,4(Fucα1,3)GlcNAc moiety. We now report the cloning and expression of two cDNAs encoding the relevant active α1,3-FucTs (α1,3-fucosyltransferases). The first sequence, closest to that of fruitfly (Drosophila melanogaster) FucTA, was found to be a core α1,3-FucT (EC 2.4.1.214), as judged by several enzyme and biochemical assays. The second cDNA encoded an enzyme, most related to Drosophila FucTC, that was shown to be capable of generating the Lex [Galβ1-4(Fucα1-3)GlcNAc] epitope in vitro and is the first Lewis-type α1,3-FucT (EC 2.4.1.152) to be described in insects. The transcription levels of these two genes in various tissues were examined: FucTA was found to be predominantly expressed in the brain tissue and venom glands, whereas FucTC transcripts were detected at highest levels in venom and hypopharyngeal glands. Very low expression of a third homologue of unknown function, FucTB, was also observed in various tissues. The characterization of these honey-bee gene products not only accounts for the observed α1,3-fucosylation of bee-venom glycoproteins, but is expected to aid the identification and subsequent down-regulation of the FucTs in insect cell lines of biotechnological importance.
A novel interaction between DNA ligase III and DNA polymerase γ plays an essential role in mitochondrial DNA stability
Authors: De Ananya , Campbell Colin
Published: January 2007

The data in the present study show that DNA polymerase γ and DNA ligase III interact in mitochondrial protein extracts from cultured HT1080 cells. An interaction was also observed between the two recombinant proteins in vitro. Expression of catalytically inert versions of DNA ligase III that bind DNA polymerase γ was associated with reduced mitochondrial DNA copy number and integrity. In contrast, overexpression of wild-type DNA ligase III had no effect on mitochondrial DNA copy number or integrity. Experiments revealed that wild-type DNA ligase III facilitates the interaction of DNA polymerase γ with a nicked DNA substrate in vitro, and that the zinc finger domain of DNA ligase III is required for this activity. Mitochondrial protein extracts prepared from cells overexpressing a DNA ligase III protein that lacked the zinc finger domain had reduced base excision repair activity compared with extracts from cells overexpressing the wild-type protein. These data support the interpretation that the interaction of DNA ligase III and DNA polymerase γ is required for proper maintenance of the mammalian mitochondrial genome.
Role of Ca2+ activation and bilobal structure of calmodulin in nuclear and nucleolar localization
Authors: Thorogate Richard , Török Katalin
Published: January 2007

Ca2+ signalling to the nucleus is thought to occur by calmodulin entry into the nucleus where calmodulin has many functions. In the present study we have investigated the role of Ca2+ and the N- and C-terminal lobes of calmodulin in its subnuclear targeting by using fluorescently labelled calmodulin and its mutants and confocal microscopy. Our data show, first, that Ca2+ stimulation induces a reorganization of subnuclear structures to which apo-calmodulin can bind. Secondly, Ca2+-independent association of the C-terminal lobe is seen with subnuclear structures such as chromatin, the nuclear envelope and the nucleoli. Thirdly, Ca2+-dependent accumulation of both calmodulin and the C-terminal calmodulin lobe occurs in the nucleoli. The N-terminal lobe of calmodulin does not show significant binding to subnuclear structures although, similarly to the C-terminal lobe, it accumulates in the nucleoplasm of wheat germ agglutinin-blocked nuclei suggesting that a facilitated nuclear export mechanism exists for calmodulin.
Domains 16 and 17 of tropoelastin in elastic fibre formation
Authors: Wachi Hiroshi , Sato Fumiaki , Nakazawa Junji , Nonaka Risa , Szabo Zoltan , Urban Zsolt , Yasunaga Takuo , Maeda Iori , Okamoto Koji , Starcher Barry C. , Li Dean Y. , Mecham Robert P. , Seyama Yoshiyuki
Published: January 2007

Naturally occurring mutations are useful in identifying domains that are important for protein function. We studied a mutation in the elastin gene, 800−3G>C, a common disease allele for SVAS (supravalvular aortic stenosis). We showed in primary skin fibroblasts from two different SVAS families that this mutation causes skipping of exons 16–17 and results in a stable mRNA. Tropoelastin lacking domains 16–17 (Δ16–17) was synthesized efficiently and secreted by transfected retinal pigment epithelium cells, but showed the deficient deposition into the extracellular matrix compared with normal as demonstrated by immunofluorescent staining and desmosine assays. Solid-phase binding assays indicated normal molecular interaction of Δ16–17 with fibrillin-1 and fibulin-5. However, self-association of Δ16–17 was diminished as shown by an elevated coacervation temperature. Moreover, negative staining electron microscopy confirmed that Δ16–17 was deficient in forming fibrillar polymers. Domain 16 has high homology with domain 30, which can form a β-sheet structure facilitating fibre formation. Taken together, we conclude that domains 16–17 are important for self-association of tropoelastin and elastic fibre formation. This study is the first to discover that domains of elastin play an essential role in elastic fibre formation by facilitating homotypic interactions.
Depletion of the thioredoxin homologue tryparedoxin impairs antioxidative defence in African trypanosomes
Authors: Comini Marcelo A. , Krauth-Siegel R. Luise , Flohé Leopold
Published: January 2007

In trypanosomes, the thioredoxin-type protein TXN (tryparedoxin) is a multi-purpose oxidoreductase that is involved in the detoxification of hydroperoxides, the synthesis of DNA precursors and the replication of the kinetoplastid DNA. African trypanosomes possess two isoforms that are localized in the cytosol and in the mitochondrion of the parasites respectively. Here we report on the biological significance of the cTXN (cytosolic TXN) of Trypanosoma brucei for hydroperoxide detoxification. Depending on the growth phase, the concentration of the protein is 3–7-fold higher in the parasite form infecting mammals (50–100 μM) than in the form hosted by the tsetse fly (7–34 μM). Depletion of the mRNA in bloodstream trypanosomes by RNA interference revealed the indispensability of the protein. Proliferation and viability of cultured trypanosomes were impaired when TXN was lowered to 1 μM for more than 48 h. Although the levels of glutathione, glutathionylspermidine and trypanothione were increased 2–3.5-fold, the sensitivity against exogenously generated H2O2 was significantly enhanced. The results prove the essential role of the cTXN and its pivotal function in the parasite defence against oxidative stress.
1.8 Å bright-state structure of the reversibly switchable fluorescent protein Dronpa guides the generation of fast switching variants
Authors: Stiel Andre C. , Trowitzsch Simon , Weber Gert , Andresen Martin , Eggeling Christian , Hell Stefan W. , Jakobs Stefan , Wahl Markus C.
Published: January 2007

RSFPs (reversibly switchable fluorescent proteins) may be repeatedly converted between a fluorescent and a non-fluorescent state by irradiation and have attracted widespread interest for many new applications. The RSFP Dronpa may be switched with blue light from a fluorescent state into a non-fluorescent state, and back again with UV light. To obtain insight into the underlying molecular mechanism of this switching, we have determined the crystal structure of the fluorescent equilibrium state of Dronpa. Its bicyclic chromophore is formed spontaneously from the Cys62–Tyr63–Gly64 tripeptide. In the fluorescent state, it adopts a slightly non-coplanar cis conformation within the interior of a typical GFP (green fluorescent protein) β-can fold. Dronpa shares some structural features with asFP595, another RSFP whose chromophore has previously been demonstrated to undergo a cis–trans isomerization upon photoswitching. Based on the structural comparison with asFP595, we have generated new Dronpa variants with an up to more than 1000-fold accelerated switching behaviour. The mutations which were introduced at position Val157 or Met159 apparently reduce the steric hindrance for a cis–trans isomerization of the chromophore, thus lowering the energy barrier for the blue light-driven on-to-off transition. The findings reported in the present study support the view that a cis–trans isomerization is one of the key events common to the switching mechanism in RSFPs.
The low-density lipoprotein receptor-related protein 1 (LRP1) mediates the endocytosis of the cellular prion protein
Authors: Taylor David R. , Hooper Nigel M.
Published: January 2007

PrPC (cellular prion protein) is located at the surface of neuronal cells in detergent-insoluble lipid rafts, yet is internalized by clathrin-dependent endocytosis. As PrPC is glycosyl-phosphatidylinositol-anchored, it requires a transmembrane adaptor protein to connect it to the clathrin endocytosis machinery. Using receptor-associated protein and small interfering RNA against particular LDL (low-density lipoprotein) family members, in combination with immunofluorescence microscopy and surface biotinylation assays, we show that the transmembrane LRP1 (LDL receptor-related protein 1) is required for the Cu2+-mediated endocytosis of PrPC in neuronal cells. We show also that another LRP1 ligand that can cause neurodegenerative disease, the Alzheimer's amyloid precursor protein, does not modulate the endocytosis of PrPC.
NetLens: Iterative Exploration of Content-Actor Network Data
Authors: Kang Hyunmo , Plaisant Catherine , Lee Bongshin , Bederson Benjamin B.
Published: January 2007

Networks have remained a challenge for information retrieval and visualization because of the rich set of tasks that users want to accomplish. This paper offers an abstract Content-Actor network data model, a classification of tasks, and a tool to support them. The NetLens interface was designed around the abstract Content-Actor network data model to allow users to pose a series of elementary queries and iteratively refine visual overviews and sorted lists. This enables the support of complex queries that are traditionally hard to specify. NetLens is general and scalable in that it applies to any data set that can be represented with our abstract data model. This paper describes the use of NetLens with a subset of the ACM Digital Library consisting of about 4000 papers from the CHI conference written by about 6000 authors, and reports on a usability study with nine participants.
Diseconomies of Scale: A Study of Development Constraints in Small Tourism Firms in Central New Zealand
Authors: Ateljevic Jovo , Doorne Stephen
Published: January 2007

Small tourism firms (STFs) in both industrialised and developing countries, are a rapidly expanding and dynamic sector of regional tourism industries. Small firm development is being touted as the path for enhancing local economies and delivering more appropriate development to marginal and/or peripheral social, cultural and physical environments. Small firms have been also linked to creative product development and innovative entrepreneurship. Ironically, the small scale of operation, the essence of its vibrancy, also acts as a severe and debilitating constraint to development with potential negative implications for the quality and consistency of the wider regional product. Attempts to improve performance and managerial expertise within the STF sector have often proved misguided and misdirected largely due to poor understanding of the issues affecting owner/managers. This paper examines the range of influences in the external institutional environment that affect the development of small tourism firms. These include government agency roles, policy infrastructure, managerial support, and relationships with the financial sector. The discussion draws on a study of the Centre Stage macro region of New Zealand to contribute to a more integrated conceptualisation through which effective policies that enhance rather than constrain the activities of STFs can be conceived and implemented.