ART HISTORY, Issue 5 2008
CECILY J. HILSDALE
Inspired by what anthropologists have called the social life of things, this article traces the shifting significations of the Royal Crown of Hungary. As an object central to notions of legitimacy in a land that served as a battleground for Eastern and Western powers during the medieval and modern eras, the crown over its contested history has come to be seen as a composite symbol of political independence and Western cultural affiliation. A thorough archaeology of the crown, however, reveals its origins as an eleventh-century diadem designed for a Byzantine princess. Subsequently this open crown was transformed into the closed crown worn by the king of a powerful and emerging Western monarchy. In the process of this re-gendering, the object was reconceived as papal gift. Bridging both instantiations is the crown's status as a gift, replete with associations of power and subjugation that anthropologists of gift-giving practices have long recognized. [source]

The origins and present status of the radio wave controversy in NMR

CONCEPTS IN MAGNETIC RESONANCE, Issue 4 2009
D.I. Hoult
Abstract The origins, history, and present status of the controversy surrounding a quantum description of the NMR signal as being due to radio waves are traced. With the Principle of Relativity and Coulomb's Law as formal starting points and the minimum of mathematics needed for understanding, the derivation of a classical electromagnetic theory of signal reception is first given. The agreement between that classical theory and a recent NMR experiment is then presented, leading to proof that, except for the highest field imaging experiments, there is no significant contribution of radio waves to the signal. Attention is drawn to the very different properties of the near and far energy, momenta, and fields inherent in the derivation. The role of the Correspondence Principle in formulating a quantum description is then emphasized and it is shown that the standard NMR interpretation of Dicke's theory of coherent spontaneous emission,that the latter is responsible for the NMR signal,cannot be correct. Finally, the author speculates on some of the intriguing relationships found in the classical electrodynamics of NMR signal reception and attempts to relate them to a common quantum electrodynamic precept of near field interaction: that the free induction decay voltage present at the terminals of an open-circuit receiving coil is based on an exchange of virtual photons between the nuclei in a sample and the free electrons in a receiving coil. © 2009 Crown in the right of Canada. Concepts Magn Reson Part A 34A: 193,216, 2009. [source]

Effect of treatment delay upon pulp and periodontal healing of traumatic dental injuries , a review article

DENTAL TRAUMATOLOGY, Issue 3 2002
J.O. Andreasen
Abstract,,,Based on an analysis of the literature concerning parameters influencing the prognosis of traumatic dental injuries, few studies were found to have examined possible relationships between treatment delay and pulpal and periodontal ligament healing complications. It has been commonly accepted that all injuries should be treated on an emergency basis, for the comfort of the patient and also to reduce wound healing complications. For practical and especially economic reasons, various approaches can be selected to fulfill such a demand, such as acute treatment (i.e. within a few hours), subacute (i.e. within the first 24 h), and delayed (i.e. after the first 24 h). In this survey the consequences of treatment delay on pulpal and periodontal healing have been analyzed for the various dental trauma groups. Applying such a treatment approach to the various types of injuries, the following treatment guidelines can be recommended, based on our present rather limited knowledge of the effect of treatment delay upon wound healing. Crown and crown/root fractures: Subacute or delayed approach. Root fractures: Acute or subacute approach. Alveolar fractures: Acute approach (evidence however questionable). Concussion and subluxation: Subacute approach. Extrusion and lateral luxation: Acute or subacute approach (evidence however questionable). Intrusion: Subacute approach (evidence however questionable). Avulsion: If the tooth is not replanted at the time of injury, acute approach; otherwise subacute. Primary tooth injury: Subacute approach, unless the primary tooth is displaced into the follicle of the permanent tooth or occlusal problems are present; in the latter instances, an acute approach should be chosen. These treatment guidelines are based on very limited evidence from the literature and should be revised as soon as more evidence about the effect of treatment delay becomes available. [source]

From privatized to government-administered tax collection: tax farming in eighteenth-century France1

ECONOMIC HISTORY REVIEW, Issue 4 2004
EUGENE N. WHITE
The establishment of a government bureaucracy to collect taxes is regarded as one of the essential features of a modern economy. While Britain is considered a pioneer, France has been treated as a laggard because of continued reliance on tax farming. Focusing on the largest tax farm, France's late transition from private to government tax collection is explained in a principal-agent context by the difficulties of monitoring employees and borrowing at low cost in the capital market. Tax farmers continued to earn high returns, absorbing the risk of fluctuating collections, leaving the Crown with lower revenue. [source]

Thermal properties of lightweight-framed construction components at elevated temperatures

FIRE AND MATERIALS, Issue 3 2005
Noureddine Bénichou
Abstract Fire resistance behaviour of lightweight-framed assemblies is determined by defining the thermal and structural performances of the assembly when exposed to fire. To adequately model thermal behaviour in a lightweight wood-framed assembly, thermal properties of the components of the assembly at elevated temperatures must be well defined. This paper presents results of measurements of thermal properties at elevated temperatures of construction materials commonly used to build lightweight wood-framed assemblies that were conducted at the National Research Council of Canada since 1990. The test results, in graphical form, are given as a function of temperature for thermal conductivity, specific heat, mass loss and thermal expansion/contraction for wood, gypsum and insulation. In addition, the effects of temperature on the thermal conductivity, specific heat, mass loss and thermal expansion/contraction of these materials are discussed. Finally, in addition to providing a resource of information, this paper also identifies the additional thermal property tests required to complete the matrix of information. Copyright © 2005 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Richard II and the Succession to the Crown

HISTORY, Issue 303 2006
IAN MORTIMER
The discovery and publication by Michael Bennett of Edward III's entailment of the crown upon his male descendants has raised many questions about the succession in Richard II's reign, very few of which have been examined by scholars. In addition, the supposed declaration by Richard that Roger Mortimer was the heir to the throne has continued to divide opinion. Two hypotheses have recently been put forward by scholars working independently to suggest that in the 1390s Richard pursued a deliberate policy of creating confusion as to the identity of his successor. A close examination of contemporary records and the continuation of the Eulogium Historiarum reveals that Richard II's declaration of the inheritance was made in parliament in 1386 and not 1385. This allows it to be re-contextualized within the crisis of that year and to form the basis of a more accurate appraisal of the succession question in the later 1380s and 1390s. The conclusion has considerable importance for historical understandings of Henry of Bolingbroke's part in the Appellants' crisis of 1387,8, relations between Richard and the Lancastrians in the 1390s, and the inheritance of the throne in 1399. [source]

Corporations, Cathedrals and the Crown: Local Dispute and Royal Interest in Early Stuart England

HISTORY, Issue 280 2000
Catherine F. Patterson
This article investigates the jurisdictional disputes between ecclesiastical officials and civic corporations in cathedral cities in the first half of the seventeenth century and the response of central government to them. While conflict between civic and cathedral government is ancient in origin, the crown's reaction to it changed substantially over time. In the first years of the century, the crown took little interest in such disputes, allowing the parties to settle jurisdictional differences on their own, often to the advantage of civic leaders. As royal priorities shifted, however, the crown took more active steps to regulate relations between corporate government and cathedral clergy. Civic officials saw their privileges curtailed and authority questioned as the policies of the ,personal rule' altered established patterns. By tracking the course of this change, the article illuminates critical relations between centre and locality and exposes the strains felt by at least some local governments in the face of Caroline policy. [source]

Hydro-climatic impacts on the ice cover of the lower Peace River

HYDROLOGICAL PROCESSES, Issue 17 2008
Spyros Beltaos
Abstract Since the late 1960s, a paucity of ice-jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide habitat for aquatic life in the Peace,Athabasca Delta (PAD) region. Though major ice jams occur at breakup, antecedent conditions play a significant role in their frequency and severity. These conditions are partly defined by the mode of freezeup and the maximum thickness that is attained during the winter, shortly before the onset of spring and development of positive net heat fluxes to the ice cover. Data from hydrometric gauge records and from field surveys are utilized herein to study these conditions. It is shown that freezeup flows are considerably larger at the present time than before regulation, and may be responsible for more frequent formation of porous accumulation covers. Despite a concomitant rise in winter temperatures, solid-ice thickness has increased since the 1960s. Using a simple ice growth model, specifically developed for the study area, it is shown that porous accumulation covers enhance winter ice growth via accelerated freezing into the porous accumulation. Coupled with a reduction in winter snowfall, this effect can not only negate, but reverse, the effect of warmer winters on ice thickness, thus explaining present conditions. The present model is also shown to be a useful prediction tool, especially for extrapolating incomplete data to the end of the winter. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Regime-dependent streamflow sensitivities to Pacific climate modes cross the Georgia,Puget transboundary ecoregion

HYDROLOGICAL PROCESSES, Issue 24 2007
Sean W. Fleming
Abstract The Georgia Basin,Puget Sound Lowland region of British Columbia (Canada) and Washington State (USA) presents a crucial test in environmental management due to its combination of abundant salmonid habitat, rapid population growth and urbanization, and multiple national jurisdictions. It is also hydrologically complex and heterogeneous, containing at least three streamflow regimes: pluvial (rainfall-driven winter freshet), nival (melt-driven summer freshet), and hybrid (both winter and summer freshets), reflecting differing elevation ranges within various watersheds. We performed bootstrapped composite analyses of river discharge, air temperature, and precipitation data to assess El Niño,Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) impacts upon annual hydrometeorological cycles across the study area. Canadian and American data were employed from a total of 21 hydrometric and four meteorological stations. The surface meteorological anomalies showed strong regional coherence. In contrast, the seasonal impacts of coherent modes of Pacific circulation variability were found to be fundamentally different between streamflow regimes. Thus, ENSO and PDO effects can vary from one stream to the next within this region, albeit in a systematic way. Furthermore, watershed glacial cover appeared to complicate such relationships locally; and an additional annual streamflow regime was identified that exhibits climatically driven non-linear phase transitions. The spatial heterogeneity of seasonal flow responses to climatic variability may have substantial implications to catchment-specific management and planning of water resources and hydroelectric power generation, and it may also have ecological consequences due to the matching or phase-locking of lotic and riparian biological activity and life cycles to the seasonal cycle. The results add to a growing body of literature suggesting that assessments of the streamflow impacts of ocean,atmosphere circulation modes must accommodate local hydrological characteristics and dynamics. Copyright © 2007 John Wiley & Sons, Ltd. The copyright in Paul H. Whitfield's contribution belongs to the Crown in right of Canada and such copyright material is reproduced with the permission of Environment Canada. [source]

The role of waves in ice-jam flooding of the Peace-Athabasca Delta

HYDROLOGICAL PROCESSES, Issue 19 2007
Spyros Beltaos
Abstract Since the late 1960s, a paucity of ice-jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide habitat for aquatic life in the Peace-Athabasca Delta (PAD) region. To identify the causes of this trend, and to develop mitigation or adaptation strategies under present and future climatic conditions, it is necessary to understand the mechanisms that lead to breakup of the ice cover and jamming within the delta reach of Peace River. Because the lower Peace is extremely flat, the long-period waves caused by spring snowmelt are not generally capable of dislodging the winter ice cover, even under conditions of very high flow. The ice cover decays in place and rubble generation, an essential condition for ice jamming, does not occur. However, major jams do, on occasion, form in the middle section of the river and make their way to the delta via repeated releases and stalls. Each release generates a steep wave which can greatly amplify the hydrodynamic forces that are applied on the ice cover and bring about its dislodgment. This is quantified for the lower Peace River by applying recently developed methodology to local hydrometric data. Detailed in situ observations in the spring of 2003, and additional data from 1997 and 2002, fully corroborate this conclusion. Implications to other flat rivers of northern Canada are discussed. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Ice regime of the lower Peace River and ice-jam flooding of the Peace-Athabasca Delta

HYDROLOGICAL PROCESSES, Issue 19 2006
Spyros Beltaos
Abstract The Peace-Athabasca Delta (PAD) in northern Alberta is one of the world's largest inland freshwater deltas, home to large populations of waterfowl, muskrat, beaver, and free-ranging wood bison. Beginning in the mid-1970s, a paucity of ice-jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide a habitat for aquatic life in the PAD region. Using archived hydrometric data and in situ observations, the ice regime of the lower Peace is described and quantified, setting the stage for identification of the conditions that lead to ice-jam flooding and replenishment of Delta habitat. The first such condition is the occurrence of a mechanical, as opposed to a thermal, breakup event; second, the river flow should be at least 4000 m3/s; and third, an ice jam should form within the last 50 km of the Peace River. The type of breakup event depends on the freeze-up stage and spring flow. The former has increased as a result of flow regulation, and the latter has decreased owing to changing climatic patterns. Both trends tend to inhibit the occurrence of mechanical breakups and contribute to less frequent ice-jam flooding. Potential mitigation strategies are discussed. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Snow, frozen soils and permafrost hydrology in Canada, 1999,2002

HYDROLOGICAL PROCESSES, Issue 1 2005
Ming-Ko Woo
Abstract An overview is provided of Canadian research on snow, frozen soils and permafrost hydrology for 1999,2002, the period between the 1999 IUGG meeting in Birmingham and the 2003 IUGG in Sapporo. Snow research during this period emphasized the blowing snow and sublimation processes, the role of trees in snow distribution, and melt and the effect of heat advection on snowmelt, from patch to regional scales. Regional-scale studies, largely in connection with the Mackenzie GEWEX study, examined the snow conditions of the lower Mackenzie basin and developed a coupled land surface scheme,hydrological model that incorporates snow processes. In frost hydrology, the effects of organic soils on runoff generation and flow delivery were given much attention. Field investigations ranged from plot to hillslope scales, and the results indicate that organic layers of high porosity permit the production of quick flow, even when frozen. Highly fractured bedrock in the Canadian Shield has likewise the effect of permitting snowmelt infiltration at below-freezing temperatures. Finally, changes in snow-covered areas and in snow equivalent over periods from a decade to a century were examined. The responses of snow and ground ice to the warm year of 1998 were also studied as an indication of hydrological responses to climatic warming. Copyright © 2005 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Infiltration and solute transport under a seasonal wetland: bromide tracer experiments in Saskatoon, Canada

HYDROLOGICAL PROCESSES, Issue 11 2004
David F. Parsons
Abstract In the northern glaciated plain of North America, the duration of surface water in seasonal wetlands is strongly influenced by the rate of infiltration and evaporation. Infiltration also plays important roles in nutrient exchange at the sediment,water interface and groundwater recharge under wetlands. A whole-wetland bromide tracer experiment was conducted in Saskatchewan, Canada to evaluate infiltration and solute transport processes. Bromide concentrations of surface water, groundwater, sediment pore water and plant tissues were monitored as the pond water-level gradually dropped until there was no surface water. Hydraulic head gradients showed strong lateral flow from under the wetland to the treed riparian zone during the growing season. The bromide mass balance analysis showed that in early spring, almost 50% of water loss from the wetland was by infiltration, and it increased to about 70% in summer as plants in and around the wetland started to transpire more actively. The infiltration contributed to recharging the shallow, local groundwater under the wetland, but much of it was taken up by trees without recharging the deeper groundwater system. Emergent plants growing in the wetlands incorporated some bromide, but overall uptake of bromide by vegetation was less than 10% of the amount initially released. After one summer, most of the subsurface bromide was found within 40,80 cm of the soil surface. However, some bromide penetrated as deep as 2,3 m, presumably owing to preferential flow pathways provided by root holes or fractures. Copyright © 2004 Crown in the Right of Canada. Published by John Wiley & Sons, Ltd. [source]

Comparing the hydrology of grassed and cultivated catchments in the semi-arid Canadian prairies

HYDROLOGICAL PROCESSES, Issue 3 2003
G. van der Kamp
Abstract At the St Denis National Wildlife Area in the prairie region of southern Saskatchewan, Canada, water levels in wetlands have been monitored since 1968. In 1980 and 1983 a total of about one-third of the 4 km2 area was converted from cultivation to an undisturbed cover of brome grass. A few years after this conversion all the wetlands within the area of grass dried out; they have remained dry since, whereas wetlands in adjacent cultivated lands have held water as before. Field measurements show that introduction of undisturbed grass reduces water input to the wetlands mainly through a combination of efficient snow trapping and enhanced infiltration into frozen soil. In winter, the tall brome grass traps most of the snowfall, whereas in the cultivated fields more wind transport of snow occurs, especially for short stubble and fallow fields. Single-ring infiltration tests were conducted during snowmelt, while the soil was still frozen, and again in summer. The infiltrability of the frozen soil in the grassland is high enough to absorb most or all of the snowmelt, whereas in the cultivated fields the infiltration into the frozen soil is limited and significant runoff occurs. In summer, the infiltrability increases for the cultivated fields, but the grassland retains a much higher infiltrability than the cultivated land. The development of enhanced infiltrability takes several years after the conversion from cultivation to grass, and is likely due to the gradual development of macropores, such as root holes, desiccation cracks, and animal burrows. Copyright ©2002 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Dynamical versus statistical downscaling methods for ocean wave heights

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2010
Xiaolan L. Wang
Abstract In this study, dynamical and statistical downscaling methods for estimating seasonal statistics of significant wave heights (SWH) were intercompared, with the downscaling results being evaluated against the ERA40 wave data in terms of climatological characteristics and interannual variability. It was also shown that biases in climate-model-simulated climate and variability of the atmospheric circulation (or predictors in general) can result in large biases in the estimated climate and variability of SWH (or the predictand in general), and that such biases can be effectively diminished by using standardized predictor quantities in statistical downscaling models. In dynamical downscaling, however, model variability biases remain to be dealt with, whereas the effects of model climate biases can be reduced to some extent by replacing the climate-model-simulated wind climate with the observed one. Therefore, the dynamical approach was found to be not as good as the statistical methods in terms of reproducing the observed climate and interannual variability of the predictand, although it bears substantial similarity to the statistical methods in terms of projected possible future changes. Also, it was shown that the observed interannual variability of seasonal statistics (including extremes) can be better reproduced by using 12-hourly, rather than seasonal, data in statistical downscaling. This stresses the importance of availability of higher-resolution data from climate model outputs. Nevertheless, a non-stationary extreme value model with covariates was found to be the best in reproducing the observed climate of extremes. All the statistical downscaling methods and the intercomparison results are applicable to other climate variables (not limited to ocean wave heights). Copyright © 2009 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Downscaled GCM projections of winter and summer mass balance for Peyto Glacier, Alberta, Canada (2000,2100) from ensemble simulations with ECHAM5-MPIOM

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 11 2009
Christoph Matulla
Abstract We apply a direct downscaling approach to generate ensembles of local-scale glacier mass balance projections from coarse-scale general circulation model (GCM) data. The general modes of the atmospheric circulation over a large geographical region are linked statistically to Peyto Glacier's winter and summer balance separately. Our study focuses on the generation of ensemble projections derived from simulations with ECHAM5-MPIOM forced with Intergovernmental Panel on Climate Change - Special Report on Emission Scenarios (IPCC-SRES) A1B and B1. The resulting ensembles of mass balance projections show a moderate increase in winter balance and a steep decrease in summer balance. Together these results suggest continued frontal recession and downwasting of Peyto Glacier and a shift of the equilibrium line altitude by at least 100 m above that estimated for the 1966,2001 period suggesting that very little of the glacier will remain by 2100. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Tornado climatology of Canada revisited: tornado activity during different phases of ENSO

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 8 2001
David Etkin
Abstract Tornadoes are a significant hazard in some parts of Canada, particularly in the southern Prairie provinces and southwestern Ontario, though they are not as common as in some parts of the US. Since the early 1980s, the regional weather offices in Canada have been recording tornado event information on a routine basis, and thus data exists that can be used to update older analyses of tornado frequencies. On average, about 60 tornadoes are reported each year, though many doubtless occur that are not observed or recorded in the Environment Canada records. An analysis of tornado frequencies with El Niño,Southern Oscillation (ENSO) events suggest that the cooler La Niña events tend to suppress tornadic activity, while El Niño events tend to enhance it (though there are exceptions to this trend). Copyright © 2001 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

A network management tool for resource-partition based layer 1 virtual private networks

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2009
Jing Wu
A Layer 1 Virtual Private Network (L1-VPN) has two models for service management: the resource-partition based model and the domain-service based model. In this paper, we present a network management tool for resource-partition based L1-VPNs. A Transaction Language One (TL1) proxy is designed to achieve resource partitioning at the network element level. Building on top of a TL1 proxy, we implemented a User-Controlled LightPath (UCLP) system to support physical network brokers to assign and allocate virtually dedicated resources to customers, and to enable customers to directly manage their resources. With such a capability, customers are able to create wide area networks based on their traffic pattern, and to adjust their traffic pattern based on available resources. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Variation in Crown and Root Organic Reserves Among Lucerne Genotypes of Different Morphology and Flower Colour

JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2003
F. Fornasier
Abstract Previous evidence indicates that differences in the concentration of underground organic reserves can drive the survival and growing ability of lucerne under cold and defoliation stresses. In order to provide the selection process with further information on compounds that may influence plant performance under grazing, we assessed variations in cold-season concentrations of nitrogen and carbon reserves on genotypes that had been identified for morphological features that possibly enhance grazing tolerance. The selected genotypes encompassed distinct morphological patterns (defined as ,models') and different taxa within the Medicago sativa complex, as shown by different flower colours. Crown concentrations of reserves were determined on 90 genotypes, whereas root concentrations were measured on a subsample of 15 genotypes. Wide intergenotypic variation was observed for all reserve substances. Comparisons among models and among flower colour classes highlighted the high concentrations of crown carbohydrates and root and crown-soluble proteins of the model coded as ,D1', characterized by prostrate, rhizomatous habit and long dormancy, which largely corresponded to plants with yellow or variegated flowers, typical of ssp. falcata and ×,varia, respectively. There was a strong ,flower colour × storage organ' interaction for sugar concentration, and the results suggested a preferential compartment of sugars in the roots of purple-flowered genotypes that belonged to the ssp. sativa. A rank correlation analysis indicated a positive relationship between persistence after two years under grazing of half-sib progenies deriving from 19 genotypes out of the 90 and crown concentrations of carbohydrates of the 19 mother plants. [source]

Discovery and design of novel inhibitors of botulinus neurotoxin A: targeted ,hinge' peptide libraries

JOURNAL OF APPLIED TOXICOLOGY, Issue 1 2003
J. Hayden
Abstract Intoxication by the zinc protease botulinus neurotoxin A (BoNT-A) results from cleavage of a single Q,R bond in the neuronal protein SNAP-25, which disables the docking mechanism required for neurotransmitter release. In the present study, potential inhibitors of BoNT-A were assessed from their effects on the BoNT-A cleavage of a synthetic 17-mer peptide (SNAP-25, residues 187,203) spanning the Q,R cleavage site. Compounds that inhibited BoNT-A included thiols (zinc chelators) such as dithiothreitol, dimercaptopropanesulfonic acid, mercaptosuccinic acid and captopril. In addition, compounds containing multiple acidic functions, such as the SNARE motif V2 (ELDDRADALQ), the tripeptide Glu-Glu-Glu and the steroid glycoside glycyrrhizic acid, were effective inhibitors. ,Hinge' peptide mini-libraries (PMLs) having the structure acetyl-X1 -X2 -linker-X3 -X4 -NH2 or X1 -X2 -linker-X3, where X1,X4 were mixtures of selected amino acids and the flexible linker was 4-aminobutyric acid, also provided effective inhibition. Targeted PMLs containing the acidic amino acids Asp and Glu, the scissile-bond amino acids Gln and Arg and the zinc chelators His and Cys produced pronounced inhibition of BoNT-A. Deconvolution of these libraries will provide novel ligands with improved inhibitory potency as leads in the design of peptide mimetics to treat BoNT poisoning. Copyright ? 2003 Crown in the right of Canada. Published by John Wiley and Sons, Ltd. [source]

Subchronic toxicity of chloral hydrate on rats: a drinking water study

JOURNAL OF APPLIED TOXICOLOGY, Issue 4 2002
R. Poon
Abstract The subchronic toxicity of chloral hydrate, a disinfection byproduct, was studied in rats following 13 weeks of drinking water exposure. Male (262 ± 10 g) and female (190 ± 8 g) Sprague-Dawley rats, ten animals per group, were administered chloral hydrate via drinking water at 0.2, 2, 20 and 200 ppm. Control animals received distilled water only. Gross and microscopic examinations, serum chemistry, hematology, biochemical analysis, neurogenic amine analysis and serum trichloroacetic acid (TCA) analysis were performed at the end of the treatment period. Bronchoalveolar fluids were collected at necropsy and urine specimens were collected at weeks 2, 6 and 12 for biochemical analysis. No treatment-related changes in food and water intakes or body weight gains were observed. There were no significant changes in the weights of major organs. Except for a mild degree of vacuolation within the myelin sheath of the optic nerves in the highest dose males, there were no notable histological changes in the tissues examined. Statistically significant treatment-related effects were biochemical in nature, with the most pronounced being increased liver catalase activity in male rats starting at 2 ppm. Liver aldehyde dehydrogenase (ALDH) was significantly depressed, whereas liver aniline hydroxylase activity was significantly elevated in both males and females receiving the highest dose. A dose-related increase in serum TCA was detected in both males and females starting at 2 ppm. An in vitro study of liver ALDH confirmed that chloral hydrate was a potent inhibitor, with an IC50 of 8 µM, whereas TCA was weakly inhibitory and trichloroethanol was without effect. Analysis of brain biogenic amines was conducted on a limited number (n = 5) of male rats in the control and high dose groups, and no significant treatment-related changes were detected. Taking into account the effect on the myelin sheath of male rats and the effects on liver ALDH and aniline hydroxylase of both males and females at the highest dose level, the no-observed-effect level (NOEL) was determined to be 20 ppm or 1.89 mg kg,1 day,1 in males and 2.53 mg kg,1 day,1 in females. This NOEL is ca. 1000-fold higher than the highest concentration of chloral hydrate reported in the municipal water supply. Copyright © 2002 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Site-specific percutaneous absorption of methyl salicylate and VX in domestic swine

JOURNAL OF APPLIED TOXICOLOGY, Issue 3 2002
E. J. Scott Duncan
Abstract The site specificity of the percutaneous absorption of methyl salicylate (MeS) and the organophosphate nerve agent VX (O -ethyl S -(2-diisopropylaminoethyl) methylphosphonothioate) was examined in anaesthetized domestic swine that were fully instrumented for physiological endpoints. Four different anatomical sites (ear, perineum, inguinal crease and epigastrium) were exposed to the MeS and the serum levels were measured over a 6-h time period. The dose absorbed at the ear region was 11 ,g cm,2 with an initial flux of 0.063 ,g cm,2min,1, whereas at the epigastrium region the dose absorbed was 3 ,g cm,2 with an initial flux of 0.025 ,g cm,2min,1. For this reason further studies were carried out with VX on the ear and the epigastrium only. In animals treated with agent on the epigastrium, blood cholinesterase (ChE) activity began to drop 90 min after application and continued to decline at a constant rate for the remainder of the experiment to ca. 25% of awake control activity. At this time there were negligible signs of poisoning and the medical prognosis was judged to be good. In contrast, the ChE activity in animals receiving VX on the ear decreased to 25% of awake control values within 45 min and levelled out at 5,6% by 120 min. Clinical signs of VX poisoning paralleled the ChE inhibition, progressing in severity over the duration of the exposure. It was judged that these animals would not survive. The dramatic site dependence of agent absorption leading to vastly different toxicological endpoints demonstrated in this model system has important ramifications for chemical protective suit development, threat assessment, medical countermeasures and contamination control protocols. Copyright © 2002 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Aggregating conclusive and inconclusive information: Data and a model based on the assessment of threat

JOURNAL OF BEHAVIORAL DECISION MAKING, Issue 4 2010
Joseph V. Baranski
Abstract This study examined the process of combining conclusive and inconclusive information using a Naval threat assessment simulation. On each of 36 trials, participants interrogated 10 pieces of information (e.g., speed, direction, bearing, etc.) about "targets" in a simulated radar space. The number of hostile, peaceful, and inconclusive cues was factorially varied across targets. Three models were developed to understand how inconclusive information is used in the judgment of threat. According to one model, inconclusive information is ignored and the judgment of threat is based only on the conclusive information. According to a second model, the amount of dominant conclusive information is normalized by all of the available information. Finally, according to a third model, inconclusive information is partitioned under the assumption that it equally represents both dominant and non-dominant evidence. In Experiment 1, the data of novices (i.e., civilians) were best described by a model that assumes a partitioning of inconclusive evidence. This result was replicated in a second experiment involving variation of the global threat context. In a third experiment involving experts (i.e., Canadian Navy officers), the data of half of the participants were best described by the partitioning model and the data of the other half were best described by the normalizing model. In Experiments 1 and 2, the presence of inconclusive information produced a "dilution effect", whereby hostile (peaceful) targets were judged as less hostile (peaceful) than the predictions of the Partitioning model. The dilution effect was not evident in the judgments of the Navy officers. Copyright © 2009 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Classifying simulated air threats with fast and frugal heuristics

JOURNAL OF BEHAVIORAL DECISION MAKING, Issue 1 2007
David J. Bryant
Abstract In three experiments, subjects learned to classify simulated aircraft using four probabilistic cues then classified test sets designed to contrast predictions of several compensatory and non-compensatory heuristics. Results indicated that a proportion of subjects appeared to use a non-compensatory fast and frugal heuristic but that significant proportions used less frugal compensatory decision rules. The relative proportions of subjects exhibiting responses consistent with the fast and frugal heuristic versus other decision rules was largely unaffected by manipulations of time pressure and perceived cue uncertainty. An extreme time constraint, however, did result in significant differences in the proportions of subjects who preferred non-compensatory to compensatory decision rules. These results suggest that it is possible to model multi-attribute decision tasks like threat assessment with a fast and frugal heuristic although no single heuristic is a general model for the simulated threat assessment task. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

All-Ceramic Post, Core, and Crown: Technique and Case Report

JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 5 2001
GUILHERME CARPENA LOPES DDS
[source]

An Analysis of the Effect of a Vent Hole on Excess Cement Expressed at the Crown,Abutment Margin for Cement-Retained Implant Crowns

JOURNAL OF PROSTHODONTICS, Issue 1 2009
Dipan Patel BDS
Abstract Purpose: The labial margins of anterior implant-retained crowns are often positioned subgingivally for a superior esthetic appearance. One of the consequences of subgingival margins is the increased risk of leaving excess cement behind following cementation. This can lead to potential problems, including peri-implant inflammation, soft tissue swelling, soreness, bleeding or suppuration on probing, and bone loss. The purpose of this laboratory study was to investigate the effect of placement, location, and diameter of a vent hole on the amount of cement being expressed at the margin of an anterior implant abutment-retained crown. Materials and Methods: Three implant crown copings were fabricated to fit on the same custom abutment. Three vent diameters (0.75, 1.25, and 1.65 mm) and three locations on the palatal surface of the coping (cervico-palatally, mid-palatally, inciso-palatally) were chosen for vent hole placement. For each test, the coping was cemented onto the abutment under standardized conditions. A preweighed thin coating of cement was applied to the fit surface of the coping. The amount of cement expressed at the margin and vent hole was measured by weight and calculated as a proportion of the amount of cement placed in the coping before seating. The procedure was completed 15 times for each variable. The results were statistically analyzed using univariate ANOVA with post hoc Bonferroni-adjusted independent samples t -tests. Results: The presence of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05). The location of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05), with the exception of the mid-palatal and inciso-palatal positioning where there was no significant difference (p= 0.61) between groups. The diameter of the vent hole did not significantly influence the proportion of cement expressed at the coping margin (p= 0.096). Conclusions: When using anterior cement-retained implant crowns, the use of a 0.75-mm mid-palatal or inciso-palatal vent hole to minimize the amount of cement expressed at the margin during cementation should be considered. [source]

In vitro effects of phlorotannins from Ascophyllum nodosum (brown seaweed) on rumen bacterial populations and fermentation

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2009
Yuxi Wang
Abstract BACKGROUND: Use of brown algae (seaweed) in ruminant diets is increasing, but the effects of its phlorotannins (PT) on rumen microbial ecology have not been determined. Mixed forage (50:25:25 ground barley silage,alfalfa hay,grass hay) was used as substrate in a batch culture ruminal incubation that included PT extracted from Ascophyllum nodosum, with and without polyethylene glycol. Principal ruminal bacteria were quantified using real-time polymerase chain reaction. RESULTS: At 500 µg mL,1, PT reduced growth of Fibrobacter succinogenes by 78%, 83% and 65% at 6, 12 and 24 h (P < 0.001), Ruminococcus albus at 24 h only (P < 0.01) and did not affect R. flavefaciens. Non-cellulolytic bacteria Selenomonas ruminantium, Ruminobacter amylophilus and Prevotella bryantii were increased (P < 0.001) by PT at 12 and 24 h. Effects of PT on fermentation products (gas production, volatile fatty acid profiles and ammonia accumulation) were consistent with alterations in rumen microbial populations. CONCLUSION: The effects of PT on ruminal bacteria were species-dependent, which suggests that diet may mediate PT effects on animal performance. The variation in sensitivity of ruminal bacteria to PT reflects previously reported effects of condensed tannins from terrestrial plants on microbial populations. Copyright © 2009 Crown in the right of Canada. Published by John Wiley & Sons, Ltd [source]

Selected bioactivities of Vaccinium berries and other fruit crops in relation to their phenolic contents

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2007
Wilhelmina Kalt
Abstract Antioxidant activity, urinary tract protective activity, and cardioprotective anti-platelet effects are among the bioactivities associated with dietary phenolics. These bioactivities were measured in vitro in fruit extracts from seven Vaccinium species and five non- Vaccinium species to determine their relationship to total phenolic content and to anthocyanin and proanthocyanidin content. Berries belonging to the genus Vaccinium were particularly high in antioxidant activity and urinary tract protective anti-adhesion activity, while anti-platelet activity varied among species. There was a positive relationship between antioxidant activity (using the oxygen radical absorbing capacity (ORAC) assay) and both the total phenolic (R2 = 0.76) and anthocyanin content (R2 = 0.43) of the fruit, although there was no relationship between ORAC and proanthocyanidin content. There were no relationships between anti-adhesion activity and total phenolic content, anthocyanin content, or proanthocyanidin content. Likewise, no relationships were observed between anti-platelet activity and total phenolic content, anthocyanin content, or proanthocyanidin content. These results suggest that while antioxidant properties are characteristic of all fruit phenolics, in vitro anti-adhesion and anti-platelet bioactivities may be due to less abundant phenolic subgroups. Copyright © 2007 Crown in the right of Canada and Society of Chemical Industry [source]

Factors affecting the meat quality of veal

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2006
Tania M Ngapo
Abstract Over the last 50 years the veal industry has seen a number of changes, in particularly in production systems with the introduction and acceptance of grain-fed and heavier calves and the progressive move from individual pens to group housing. Reasons for the changes are multi-faceted of which two important players are the well-being of the animal and the public perception of the industry. Regardless of the reasons for the changes, breeders strive to attain veal conforming to the rigorous standards reflecting consumer demands. Consequently a multitude of publications exists on production factors in veal farming. However, many of these reports stop at the ,farm gate', or more correctly, the slaughterhouse, where carcass characteristics in particular are assessed. Changes in production systems generally aim to improve feed efficiency and weight gains, but often overlook meat quality aspects which ultimately dictate financial gains. This review aims to summarise the existing and available literature on factors affecting the quality of veal meat. The topics covered include the effects of breed, sex, weight or age, diet composition and dietary treatments, environment and pre-slaughter handling, and processing factors such as stunning, electrical stimulation, ageing and packaging. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

Infestation of trees by lianas in a tropical forest in Amazonian Peru

JOURNAL OF VEGETATION SCIENCE, Issue 6 2008
Geertje M.F. van der Heijden
Abstract Question: In Amazonian moist forest, four questions arose: 1. Do tree species differ in their susceptibility to lianas? 2. What host tree traits (branch-free bole height, growth rate, bark type, leaf length and adult stature) are correlated with the susceptibility of tree species to lianas infesting the trunk and the crown? 3. To what extent do spatial variables (proximity to liana-infested trees and the light environment of the tree crown) affect the likelihood of liana infestation? 4. Are spatial variables or tree traits relatively more important in influencing the susceptibility of trees to lianas? We address all questions separately for trunk and crown infestation. Location: Tambopata Nature Reserve, Peru. Methods: We collected information on liana infestation, tree morphological traits, growth, light-environment and position for 3675 trees in seven 1-ha permanent sample plots. We separated trunk from crown infestation and used correlation and logistic regression analyses for tree species and individual tree-level analyses, respectively. Results: Half of all trees were colonised by at least one liana. Of 41 relatively common dicot tree species, at least five have significantly greater and three significantly lower crown infestation rates than expected by chance. Trunk and crown infestation are influenced by different host traits , trunk infestation was only affected by bark type, while crown infestation is reduced when trees are fast-growing, tall, have low-density wood, long branch-free boles and long leaves. The likelihood of both trunk and crown infestation increases for trees growing in close proximity to another liana-infested tree, but is invariant with the light environment of tree crowns. Conclusion: Crown and trunk infestation have not been properly distinguished before; it is important to do so as the factors determining the different modes of infestation differ fundamentally. The association between crown infestation and tree traits suggests that increases in liana dominance in Amazonian forests could cause changes in forest composition, including favouring faster growing tree species with low density wood, potentially reducing the carbon stored by mature forests. [source]