Wide Front Research Articles

Diffusion Controlled Reactions, Fluctuation Dominated Kinetics, and Living Cell Biochemistry

In recent years considerable portion of the computer science community has focused its attention on understanding living cell biochemistry and efforts to understand such complication reaction environment have spread over wide front, ranging from systems biology approaches, through network analysis (motif identification) towards developing language and simulators for low level biochemical processes. Apart from simulation work, much of the efforts are directed to using mean field equations (equivalent to the equations of classical chemical kinetics) to address various problems (stability, robustness, sensitivity analysis, etc.). Rarely is the use of mean field equations questioned. This review will provide a brief overview of the situations when mean field equations fail and should not be used. These equations can be derived from the theory of diffusion controlled reactions, and emerge when assumption of perfect mixing is used.

Geophysical constraints and model of the “Saxothuringian and Rhenohercynian subductions – magmatic arc system” in NE France and SW Germany

AbstractCorrelation of geophysical and geological data with the western margin of the Bohemian massif, re-interpretation of the ECORS-DEKORP deep seismic sections, transformations and 3 D modelling of gravimetric and magnetic maps allow to define sequentional Saxothuringian and Rhenohercynian Paleozoic subduction systems in NE France and SW Germany where only 10% of the Early Paleozoic basement is outcropping. Two 35 km spaced and NE-SW trending gravity highs associated with SE dipping reflectors are interpreted as the western continuation of the Teplá Devonian paleo-subduction zone of the Saxothuringian ocean and Early Carboniferous underthrusting of the Saxothuringian passive margin, thereby defining the Saxothuringian subduction system in west Europe. South-eastwards dipping reflectors beneath the Moho are interpreted as witnesses of the Early Carboniferous subduction of the Rhenohercynian ocean. The suture is marked by the gravity high in the phyllite zone of the southern Rhenish Massif. Gravity lows in the SE of gravity highs and weak ondulating reflectors are interpreted in terms of crystalline bulges in the hangingwalls of sutures. The numerous highly magnetic anomalies correspond to magmatic bodies emplaced in the time-range 335–330 Ma, along NW dipping and sinistral normal faults. Located in the hangingwall of the Rhenohercynian subduction zone, this wide magmatic arc trends obliquely with respect to the Saxothuringian subduction system, which is almost obliterated by the wide front of magmatic bodies.

Role, Metabolism, Chemical Modifications and Applications of Hyaluronan

Hyaluronan (hyaluronic acid, HA) is a linear naturally occurring polysaccharide formed from repeating disaccharide units of N-acetyl-D-glucosamine and D-glucuronate. Despite its relatively simple structure, HA is an extraordinarily versatile glycosaminoglycan currently receiving attention across a wide front of research areas. It has a very high molar mass, usually in the order of millions of Daltons, and possesses interesting visco-elastic properties based on its polymeric and polyelectrolyte characteristics. HA is omnipresent in the human body and in other vertebrates, occurring in almost all biological fluids and tissues, although the highest amounts of HA are found in the extracellular matrix of soft connective tissues. HA is involved in several key processes, including cell signaling, wound repair and regeneration, morphogenesis, matrix organization and pathobiology. Clinically, it is used as a diagnostic marker for many disease states including cancer, rheumatoid arthritis, liver pathologies, and as an early marker for impending rejection following organ transplantation. It is also used for supplementation of impaired synovial fluid in arthritic patients, following cataract surgery, as a filler in cosmetic and soft tissue surgery, as a device in several surgical procedures, particularly as an anti-adhesive following abdominal procedures, and also in tissue engineering. This review will provide an overview of the structure and physiological role of HA, as well as of its biomedical and industrial applications. Recent advances in biotechnological approaches for the preparation of HA-based materials, and as a component of tissue scaffolding for artificial organs will also be presented.

Storm-Driven Shoreface Morphodynamics on a Low-Wave Energy Delta: The Role of Nearshore Topography and Shoreline Orientation

An analysis of storm-driven sedimentary changes on the shoreface of a low–wave-energy cuspate delta on the southern coast of Spain is examined. Bathymetric surveys, ranging from 1- to 40-m depth, were collected 2 days before and 9 days after a high-magnitude Levante storm. The storm lasted only 36 hours, with peak wind gusts of 100 km/h (28 m/s) and maximum wave heights of 7.4 m. Storms of similar magnitude have only been recorded four times in the last 20 years along this coast. The deltaic nearshore and shoreface was divided into three main morphologic and morphodynamic zones based on process-response mechanisms following the storm event. The eastern section, characterised by a steep and concave shoreface, only had minor erosion and deposition as a result of the storm. The area seaward of the river mouth, an intermediate zone where the coastline changes orientation, is characterised by a widening surf zone and an irregular shoreface out to 10-m depth before dipping steeply to 40-m depth. Poststorm changes along this transitional area resulted in the deposition of a thin veneer of sediment over a 3 km2 area from 10- to 40-m depth. The western section, a shallow and wide delta front with a double-bar, a trough, and shore-oblique topography, was modified the most by the storm, with significant upper shoreface erosion and shore-oblique erosional scars in 5–7-m depth. Results of spectral wave modelling of wave-induced force match well with observed morphological change; force is minimal along the east coast, more pronounced along the steep shoreface opposite the river mouth, and at a maximum along the west coast. It is suggested that coastal orientation, shoreface morphology (topography, gradients), and storm parameters (wave and wind direction) generated contrasting wind and wave-induced currents on the delta shoreface, resulting in spatial differences in storm response.

The 2006 outbreak of bluetongue in northern Europe—The entomological perspective

After bluetongue (BT) appeared in northern Europe in August 2006 entomological studies were implemented in all five affected Member States (MSs) to establish which species of Culicoides had acted as vectors. The findings can be summarised as follows: (i) C. imicola the principal southern European/African vector of BTV has not penetrated into northern Europe, (ii) three pools of C. obsoletus/ C. scoticus and one of C. dewulfi assayed RT-PCR-positive to BTV-8, (iii) in support of these results it was found that both potential vectors had also high parity rates (approximately 40%) indicating increased longevity favouring BTV virogenesis and transmission, (iv) furthermore, C. obsoletus/ C. scoticus and C. dewulfi occurred also widely and abundantly on sheep and cattle holdings across the entire affected region, (v) and during the latter part of the season showed strong endophily readily entering livestock buildings in significant numbers to bite the animals inside (endophagy), (vi) which demonstrates that housing at best offers only limited protection to livestock from Culicoides attacks, (vii) in contrast the potential vector C. pulicaris sensu stricto was restricted geographically, was captured rarely, had a low parity rate (10%) and was exophilic indicating it played no role in the outbreak of BT, (viii) the incrimination of C. dewulfi as a novel vector is significant because it breeds in cattle and horse dung this close association raising its vectorial potential, but (ix) problems with its taxonomy (and that of the Obsoletus and Pulicaris species complexes) illustrates the need for morphological and molecular techniques to become more fully integrated to ensure progress in the accurate identification of vector Culicoides, (x) midge densities (as adjudged by light traps) were generally low indicating northern European Culicoides to have a high vector potential and/or that significant numbers of midges are going undetected because they are biting (and transmitting BTV) during the day when light traps are not effective, and (xi) the sporadic capture of Culicoides in the winter of 2007 invites re-examination of the current definition of a vector-free period. The re-emergence of BT over a wide front in 2007 raises anew questions as to precisely how the virus overwinters and asks also that we scrutinise our monitoring systems in terms of their sensitivity and early warning capability.

Innovation in the food industry: Personalised nutrition and mass customisation

Human beings are not created equal, at least not in terms of nutritional needs. Nutritional needs are dictated by a mixture of genetics, epigenetics, personal history and lifestyle. Obvious cases of genetically-based or genetically-predisposed special nutritional needs are well known; insulin-dependent (Type 1) diabetes mellitus and phenylketonuria being good examples. Other special dietary needs are of less clear origin, but disorders such as coeliac disease, irritable bowel disease and lactose intolerance are becoming widely recognised as having strong genetic components. Additionally, there is emerging evidence of individually different responses in fat metabolism in individuals, leading to differences in lipoprotein profiles (HDL and LDL – indicators of heart health) in response to diet. Some lifestyles also give rise to special dietary requirements. This is particularly noted for athletes, who often have very specific nutritional advice. All of these examples are exceptional, relating to specific metabolic disorders or extreme lifestyle needs, with quite specific goals.This paper is concerned with an emerging trend towards personalised nutrition becoming mainstream in affluent society, with a goal of general good health, and the potential for mass customisation to provide personalised nutrition on a wide front.

Shock-related radio emission during coronal mass ejection lift-off?

Aims. We identify the source of fast-drifting decimetric-metric radio emission that is sometimes observed prior to the so-called flare continuum emission. Fast-drift structures and continuum bursts are also observed in association with coronal mass ejections (CMEs), not only flares. Methods. We analyse radio spectral features and images acquired at radio, Hα, EUV, and soft X-ray wavelengths, during an event close to the solar limb on 2 June 2003. Results. The fast-drifting decimetric-metric radio burst corresponds to a moving, wide emission front in the radio images, which is normally interpreted as a signature of a propagating shock wave. A decimetric-metric type II burst where only the second harmonic lane is visible could explain the observations. After long-lasting activity in the active region, the hot and dense loops could be absorbing or suppressing emission at the fundamental plasma frequency. The observed burst speed suggests a super-Alfvenic velocity for the burst driver. The expanding and opening loops, associated with the flare and the early phase of CME lift-off, could be driving the shock. Alternatively, an instantaneous but fast loop expansion could initiate a freely propagating shock wave. The later, complexlooking decametre-hectometre wave type III bursts indicate the existence of a propagating shock, although no interplanetary type II burst was observed during the event. The data does not support CME bow shock or a shock at the flanks of the CME as the origin of the fast-drift decimetric-metric radio source. Therefore super-Alfvenic loop expansion is the best candidate for the initiation of the shock wave, and this result challenges the current view of metric/coronal shocks originating either in the flanks of CMEs or from flare blast waves.

Wavering between radical and realistic sustainable consumption policies: in search for the best feasible trajectories

In this article radical change in the context of sustainable development is seen as a long-term process in which steady progress in the right direction is regarded as more essential than quick success. The author argues that pressing for swift radical changes bears a serious risk of becoming counter productive, because: ▪ pressing for rapid change is often wasteful and may prevent the best possible ways of exploitation of innovations; ▪ rapid change over a wide front of applications and sectors is usually impossible; ▪ pressing for rapid changes usually encounters strong opposition from interest groups, thereby risking to get bogged down in acceptability discourses. Transition management, such as for a transition towards sustainable consumption seems often to presuppose the need for radical changes. Even though the embedding function of transition management is a helpful concept and tool for sustainable consumption strategies, the lack or the negligence of the role of objective functions is a disturbing feature of transition management theories. All in all, the need for radical change should emerge as the transition process unfolds. There is no good scientific reason for a priori claims for radical changes as a kind of new dogma.

A role for RhoA in the two-phase migratory pattern of post-otic neural crest cells

Neural crest (NC) cells have been elegantly traced to follow stereotypical migratory pathways throughout the vertebrate embryo, yet we still lack complete information on individual cell migratory behaviors and how molecular mechanisms direct NC cell guidance. Here, we analyze the spatio-temporal migratory pattern of post-otic NC and the in vivo role of the small Rho GTPase, RhoA, using fluorescent cell labeling, molecular perturbation, and intravital 4D (3D+ time) confocal imaging in the intact chick embryo. We find that the post-otic NC cell migratory pattern is established in two phases with distinct cell migratory behaviors. An initial wide front of lateral-directed NC cells, led by NC from rhombomere 7 (r7), move as a distinct subpopulation. This is followed in time by fewer NC cells that migrate collectively from r7 to r8 in a follow-the-leader manner with extensive cellular extensions between cells. We show that post-otic migratory NC cells express RhoA, using RT-PCR on isolated, flow cytometry sorted NC cells and in neural tube culture explants. When RhoA function is altered by expression of a dominant negative or constitutively active form, or injection of C3, there are two major consequences. RhoA constitutively active expressing NC cells are less directional, slower and form fewer follow-the-leader chain assemblies. NC cells expressing RhoA-DN are less affective in retracting filopodia, migrate slower and also form fewer follow-the-leader chain assemblies. Together, these alterations to NC cell intrinsic signaling and cell–cell contact disrupt the precise spatio-temporal post-otic NC cell migratory pattern.

The Hatteras Front: August 2004 velocity and density structure

The Hatteras Front is a persistent mesoscale cross‐shelf oriented front off Cape Hatteras, North Carolina. It is the boundary between relatively cool, fresh Mid‐Atlantic Bight shelf waters and warmer, saltier shelf waters of the South Atlantic Bight, which both converge along‐shelf upon Cape Hatteras year round. The Frontal Interaction Near Cape Hatteras (FINCH) project was conducted in 2004–2005 to intensively sample the Hatteras Front with shipboard ADCP and undulating towed CTD. This paper documents velocity and density structures associated with the cross‐shelf oriented zone of Hatteras Front during the August 2004 field season. Property gradients across the Hatteras Front are large, with temperature (T) and salinity (S) differences of ∼4–6°C, 2–5 psu, respectively over distances of 1–2 km. The T and S are not completely compensating, and a strong density (ρ) gradient also exists, with Δρ of ∼2 kg/m3 across a gentler 10 km wide front. The density gradient results in a steric sea‐level height gradient of ∼1–2 cm across the Front, which is in approximate geostrophic balance with a surface intensified jet, directed shoreward along the cross‐shelf oriented Front. The velocity is sheared with depth at 3.0 × 10−2 to 5.0 × 10−2 s−1 in the upper 5 m of the jet; a rate consistent with the density gradient according to the thermal wind relationship. Shoreward transport of ∼4.8 × 104 m3/s results from the surface intensified jet. The structure of the velocity field associated with the Hatteras Front resembles that of a slope‐controlled buoyant plume, as described by Lentz and Helfrich (2002). Velocity and density structures are similar during both advancing (southwestward) and retreating (northeastward) motion of the Front.

Microstructural changes during wear by plastic deformation of cemented carbide and cermet cutting inserts

The microstructure of one WC-Co and two Ti(C,N)-WC-Co cutting inserts has been studied before and after plastic deformation, caused by high-speed turning. It was found that after deformation, the binder phase had infiltrated some of the grain boundaries and formed lamellae between the hard phase grains. The infiltration of grain boundaries was assumed to occur by a stress-induced dissolution along the grain boundaries of the hard phase grains as a wide front of binder phase, rather than gradually by Co grain boundary diffusion. Some localized dissolution of the hard phase could also be seen as faceting of grains in WC-Co and at triple points in cermets. It was concluded that the plastic deformation occurs by grain boundary infiltration with simultaneous grain boundary sliding. The rate of deformation is controlled by grain boundary infiltration through dissolution of the hard phase grains.

Identifying grand research questions in the solid‐earth sciences

Progress in the solid‐Earth sciences has been remarkable over the past few decades, driven by the availability of new instruments, improved modeling capabilities, reduced barriers to cooperation with scientists in other countries, and increased coordination with other disciplines, such as astronomy and biology. With research advancing on such a wide front, it can be difficult to define the frontiers of scientific inquiry and to convey that information in a way that captures the imaginations of the scientific community, the U.S. Congress, U.S. federal agencies, and the general public.At the request of program managers at the U.S. Department of Energy, U.S. National Science Foundation, U.S. Geological Survey, and NASA, the U.S. National Academies has assembled a committee of experts to identify the grand research questions driving the solid‐Earth sciences. Although other reports have identified research priorities in this area, just a few (such as “Living on a restless planet,” 63 pp., NASA Solid Earth Science Working Group, Pasadena, Calif., 2002) have cast them mainly as compelling, fundamental science questions. Such ‘big picture’ questions may require decades to answer, and research support from many government agencies and organizations. The answers to these questions could profoundly affect our understanding of the Earth.

Nutrition in War and Peace

Nutrition in War and Peace

Moving toward a unified effort to understand the nature and causes of language disorders

The nature and causes of language disorders are research topics familiar to the readership ofApplied Psycholinguistics. Current inquiries place these topics in a dynamic and sprawling multidisciplinary context manifested through investigations of linguistic acquisition, cognitive development, genetics, neurocortical processes, cognitive neurolinguistics, behavioral phenotypes, and language intervention. This list is not complete by any means, but it does suggest the wide front of the current search for better knowledge about what causes language disorders and the dimensions of language acquisition that are affected. Although there is considerable momentum underway in current inquiries, the full potential for scientific advancement is hampered by fragmentation in the field, in part attributable to partitioning by diagnostic categories of affectedness. Investigators (and their funding sources) often focus on a particular clinical group, such as specific language impairment (SLI), autism/autism spectrum disorders (ASD), Williams syndrome (WS), Down syndrome (DS), or fragile X syndrome (FXS). Although this is not exclusively the case, it is relatively difficult to carry out comparative studies across the multiple clinical conditions in which language disorders appear and to monitor developments across such a wide front of investigation. The consequence is that findings are distributed across different publication outlets and different groups of scholars, a situation that can limit our appreciation of the ways in which language disorders are manifest, and the identification of common etiological factors.

NEW TECHNICAL SOLUTIONS FOR CONSTRUCTION OF THE MINSK RING HIGHWAY

In Byelorussia the network of highways intensively develops. For their construction and reconstruction modern technologies are used. The sample of new technical decisions in road construction can be counted the Minsk ring highway. Questions of erection of an earthen cloth on bogs have been here successfully solved. Geosynthetic materials, blacktop with cellulose fibres, noise protection screens from profile metal are used. Construction of bridges and overpasses was carried out with wide application of preliminary intense bearing designs. The bridge cloth and sidewalks are executed from monolithic concrete. For strengthening slopes, ridge vibropressing plates are applied. All works were carried out by wide front with maximal use of high‐efficiency road technics. With the purpose of management of a condition roadway parts on the Minsk belt line three road measuring stations are constructed. They allow to carry out works under the account of transport streams and influences of meteorological‐climatic factors on the traffic‐operational condition of a highway.

Asian demand pushes up commodity prices

Dollar prices for industrial raw materials have increased along a wide front, and oil prices are almost as high as they were before the Iraq war. Due to the weak dollar, however, consumers in the euro area have been relatively unaffected so far. Demand for raw materials will remain strong. Must we brace ourselves for a further sharp increase in commodity prices?

Electrogram polarity reversal as an additional indicator of breakthroughs from the left atrium to the pulmonary veins

ObjectivesWe assessed the anatomical distribution and electrogram characteristics of breakthrough from the left atrium (LA) to the pulmonary veins (PVs). BackgroundLocalization of LA-PV breakthrough is an important technique for PV ablation in patients with atrial fibrillation (AF). MethodsA total of 157 patients with paroxysmal AF underwent PV disconnection guided by mapping with a circumferential 10-electrode catheter. Radiofrequency (RF) current was delivered ostially at the site(s) of earliest activation (113 patients) or electrogram polarity reversal defined by opposite polarity across adjacent bipoles (44 patients). Breakthrough sites were proved by changes in pulmonary vein potential activation sequence occurring as a result of localized RF delivery and were classified into four segments around the ostium (top, bottom, anterior, posterior). Results of mapping and ablation were compared between the two groups. ResultsA total of 99% of 411 targeted PVs were successfully disconnected in both groups. Breakthroughs were most frequent at the bottom of superior PVs (85% prevalence) and the top of inferior PVs (75% prevalence). A wide activation front (>5 synchronous bipoles) indicating broad breakthrough was observed in 18% of PVs. Polarity reversal occurred with 88% sensitivity and 91% specificity at breakthrough sites. Polarity reversal was restricted to fewer bipoles (2.0 ± 0.4 bipoles vs. 3.4 ± 2.0 bipoles, p < 0.01) compared with earliest activation. Shorter RF application time was required to disconnect PVs with wide synchronous activation using polarity reversal compared with using conventional earliest activity (10.3 ± 3.0 min vs. 12.3 ± 3.4 min, p < 0.05). ConclusionsBipolar electrogram polarity reversal allows more precise localization of breakthrough compared with the earliest activation, particularly in cases of wide synchronous PV activation.

Rates of volcanic deposition, facies changes and movements in a dynamic basin: the Nuussuaq Basin, West Greenland, around the C27n-C26r transition

Abstract The initial stages of Palaeogene volcanism in the Nuussuaq Basin in West Greenland were characterized by eruption of basaltic and picritic magmas through sediments of Cretaceous to early Paleocene age into a marine or lowlying coastal environment. Recent magnetostratigraphic work has recognized the C27n-C26r transition (estimated duration less than 10 ka and here assumed to be 5 ka) as a c. 170 m thick zone within a succession of thin picritic lava flows. Multimodel photogrammetry combined with chemical and lithological analysis of the volcanic rocks has allowed detailed 3D analysis of the facies variation within this narrow time window. Subaerial lavas flowed eastwards over a more than 40 km wide front. On northern Disko they covered an existing lava plateau and buried a subaerial landscape of dipping Cretaceous sandstones, while on Nuussuaq they flowed into an up to 700 m deep marine embayment and formed prograding hyaloclastite fans passing into fine-clastic mass flows. With a progradation rate of 0.5–1 m a −1 the palaeogeography of the basin changed considerably during the short time interval. In addition to substantial basin subsidence, the volcanic facies changes have also preserved a record of synvolcanic differential movement of extensional fault blocks. The following parameters are estimated for the volcanism within the Nuussuaq Basin during the C27n-C26r transition: Production rate c. 0.042 km 3 a −1 , productivity c. 1.2 × 10 −3 km 3 a −1 km −1 (rift), volcanic aggradation c. 33 m ka −1 , subsidence c. 25 m ka −1 . If the volcanism evolved continuously at this high aggradation rate, all of the Vaigat Formation could have erupted in 70 ka. However, the complex geological record indicates a much longer total duration, and the volcanism must have had an intermittent character.

Between Waking and Sleeping

This is what happened to me today: sitting in the coffeeshop before work, I glanced through the wide front window out at the patio and saw a girl crying on the steps. I looked around behind me: the usual action, a few people walled in be hind newspapers at widely-separated tables, a pair of lovers with their heads bent together over photographs, the green-aproned girls behind the counter busying about with trays of pastries and the cappuccino machine. An indis tinct string melody on the speakers, a warm scent of coffee and cinnamon; the typical effects of the day; and on the steps outside, unnoticed by anyone but myself, this crying girl?this sobbing girl, actually, her sleek black-haired head bent down toward her clenched knees, her sUm shoulders shaking be neath a black velvet suit jacket. She wore open-toed shoes and her toenails were painted the color of earth. She was twenty-two, twenty-five, something Uke that. I watched, mesmerized, as sadness poured out of her Uke water onto stones. Through the glass I could hear Uttle besides the more strident of street noises: sirens, rumbling trucks. Why would she just sit there and sob? I won dered. Isn't there somewhere she can go? Someone she can call? It was clearly about to rain; the clouds were dark and heavy, the air thick with breeze. The girl cried and cried.

Hyaluronan, a common thread.

Hyaluronan, nature's simplest, but still exceptionally versatile glycosaminoglycan, is currently the focus of attention across a wide front of research; from cell biology, morphogenesis, matrix organization, pathobiology to tissue engineering. This macromolecule has entangled me in a number of puzzling and challenging projects over the past 3 decades. These entertaining encounters are outlined in this retrospective.