bluuebunny/crossref_metadata_2025 huggingface dataset:
Using cryptotephras to extend regional tephrochronologies: An example from southeast Alaska and implications for hazard assessment
Authors: Payne Richard , Blackford Jeffrey , van der Plicht Johannes
Published: December 2007

Cryptotephrochronology, the use of hidden, diminutive volcanic ash layers to date sediments, has rarely been applied outside western Europe but has the potential to improve the tephrochronology of other regions of the world. Here we present the first comprehensive cryptotephra study in Alaska. Cores were extracted from five peatland sites, with cryptotephras located by ashing and microscopy and their glass geochemistry examined using electron probe microanalysis. Glass geochemical data from nine tephras were compared between sites and with data from previous Alaskan tephra studies. One tephra present in all the cores is believed to represent a previously unidentified eruption of Mt. Churchill and is named here as the ‘Lena tephra’. A mid-Holocene tephra in one site is very similar to Aniakchak tephra and most likely represents a previously unidentified Aniakchak eruption, ca. 5300–5030 cal yr BP. Other tephras are from the late Holocene White River eruption, a mid-Holocene Mt. Churchill eruption, and possibly eruptions of Redoubt and Augustine volcanoes. These results show the potential of cryptotephras to expand the geographic limits of tephrochronology and demonstrate that Mt. Churchill has been more active in the Holocene than previously appreciated. This finding may necessitate reassessment of volcanic hazards in the region.
The parasitoid complex ofParthenolecanium corniBouché in the city of Tbilisi and its surroundings and comparison with some other European countries
Authors: Japoshvili G. , Gabroshvili N. , Japoshvili B.
Published: December 2007

The European fruit lecanium (EFL),Parthenolecanium corniBouché (Hemiptera: Coccoidea), is a common and harmful soft scale, which attacksFraxinus oxycarpaWilld. and other ornamental and orchard plants in Tbilisi, Georgia. This study investigates the phenology, degree of plant damage and effect of parasitoids on this scale in Tbilisi, a densely populated area. We present data on the 32 species of chalcidoid parasitoids recorded from EFL in Georgia and south-eastern Europe. The scale is heavily parasitized in Tbilisi, but we did not find any variation in seasonal abundance. The most common parasitoid of EFL wasBlastothrix longipennis(Hymenoptera: Encyrtidae).
A multiplex PCR assay for the simultaneous identification of three mealybug species (Hemiptera: Pseudococcidae)
Authors: Saccaggi D.L. , Krüger K. , Pietersen G.
Published: December 2007

Molecular species identification is becoming more wide-spread in diagnostics and ecological studies, particularly with regard to insects for which morphological identification is difficult or time-consuming. In this study, we describe the development and application of a single-step multiplex PCR for the identification of three mealybug species (Hemiptera: Pseudococcidae) associated with grapevine in South Africa:Planococcus ficus(vine mealybug),Planococcus citri(citrus mealybug) andPseudococcus longispinus(longtailed mealybug). Mealybugs are pests on many commercial crops, including grapevine, in which they transmit viral diseases. Morphological identification of mealybug species is usually time-consuming, requires a high level of taxonomic expertise and usually only adult females can be identified. The single-step multiplex PCR developed here, based on the mitochondrial cytochromecoxidase subunit 1 (CO I) gene, is rapid, reliable, sensitive, accurate and simple. The entire identification protocol (including DNA extraction, PCR and electrophoresis) can be completed in approximately four hours. Successful DNA extraction from laboratory and unparasitized field-collected individuals stored in absolute ethanol was 97%. Specimens from which DNA could be extracted were always correctly identified (100% accuracy). The technique developed is simple enough to be implemented in any molecular laboratory. The principles described here can be extended to any organism for which rapid, reliable identification is needed.
Mating activity of Bactrocera cacuminata (Hering) (Diptera: Tephritidae) on its larval host plant Solanum mauritianum Scopoli in southeast Queensland
Authors: Drew R.A.I. , Rodgers D.J. , Vijaysegaran S. , Moore C.J.
Published: December 2007

A detailed study was conducted on the mating behaviour of Bactrocera cacuminata (Hering) (Diptera: Tephritidae) in nature. Plant tissues from Solanum mauritianum Scopoli, the primary larval host for B. cacuminata, were also analysed for methyl eugenol content. In the field, over a 15 month period, 44,171 observations of adult B. cacuminata individuals were made including 1109 mating pairs on S. mauritianum. Calling behaviour consisting of wing fanning and anus beating by males was also consistently observed on the underside of leaves of S. mauritianum after sunset. Female flies that arrived into these groups of 10–15 calling males were mated and often remained coupled until dawn. No methyl eugenol was detected from the analysis of leaves, flowers and fruits of S. mauritianum. Thus, B. cacuminata does not need to aggregate at sites where methyl eugenol is present and the hypothesis that this chemical plays a role in the selection of mating sites by B. cacuminata is not supported by the current study. It is concluded that S. mauritianum is the primary site of mating for B. cacuminata in nature and that the concept that the larval host plant is the centre of activity for dacine fruit flies remains robust, being fully supported by the results of this study.
Kampimodromus aberrans(Acari: Phytoseiidae) from the USA: morphological and molecular assessment of its density
Authors: Tixier M.-S. , Kreiter S. , Croft B.A. , Cheval B.
Published: December 2007

Morphological measurements and a mitochondrial molecular marker (COI) were used to identity specimens reported asKampimodromus aberranson hazelnut in the USA. Several species and populations of this genus were studied to assist with identification. Both data types showed that specimens from the USA differed fromK. aberransfrom other regions. USA specimens seem to belong to the same species asKampimodromusspecimens from France on hazelnut. These mites were morphologically similar toKampimodromus coryliandK. corylosus, which according to the original descriptions, are distinguished by the presence or absence of a tooth on the movable digit of the chelicera, withK. corylihaving one tooth andK. corylosusnone. As chelicerae ofKampimodromusfrom hazelnut in the USA and France are toothless, they are assigned to the speciesK. corylosus. Studies showed that morphological characters traditionally used to identifyKampimodromusspecies, such as setal length, are of less value than other characters that are difficult to observe, such as the numbers of solenostomes and the presence of teeth on the movable digit of the chelicerae. Some synonyms are discussed.
Molecular characterization ofGonatocerus tuberculifemur(Ogloblin) (Hymenoptera: Mymaridae), a prospectiveHomalodisca vitripennis(Germar) (Hemiptera: Cicadellidae) biological control candidate agent from South America: divergent clades
Authors: de León J.H. , Logarzo G.A. , Triapitsyn S.V.
Published: December 2007

We genetically characterized the prospective South American egg parasitoid candidate,Gonatocerus tuberculifemur, of the glassy-winged sharpshooter (GWSS),Homalodisca vitripennis, for a neoclassical biological control program in California. Two molecular methods, inter-simple sequence repeat-polymerase chain reaction DNA fingerprinting and a phylogeographic approach inferred from the mitochondrial cytochrome oxidase subunit I gene (COI), were utilized. Five geographic populations from South America were analyzed; in addition, a phylogenetic analysis was performed with several named and one unnamedGonatocerusspecies using the COI gene. DNA fingerprinting demonstrated a fixed geographic banding pattern difference in the population from San Rafael, Mendoza Province, Argentina. The COI analysis uncovered haplotype or geographic structure inG. tuberculifemur. A neighbour-joining distance (NJ) and a single most parsimonious tree (MP) clustered the populations into two well-supported distinct clades with strong bootstrap values (97–99% and 92–99%, respectively) with populations from San Rafael clustering into clade 2 and the rest of the populations clustering into clade 1. No haplotype sharing was observed between individuals from the two clades. Phylogenetic analyses performed by NJ and MP methods with 15Gonatocerusspecies confirmed species boundaries and again uncovered two distinct clades inG. tuberculifemurwith strong bootstrap support (95–100% and 68–100%, respectively). However, the NJ tree supported the morphologically defined relationships better than the MP tree. The molecular evidence in the present study is suggestive of a species level divergence. BecauseG. tuberculifemuris under consideration as a potential biological control agent for GWSS in California, understanding cryptic variation in this species is critical.
Seasonal and annual genotypic variation and the effect of climate on population genetic structure of the cereal aphidSitobion avenaein northern France
Authors: Dedryver C.-A. , Le Gallic J.-F. , Haack L. , Halkett F. , Outreman Y. , Simon J.-C.
Published: December 2007

Changes in the genetic structure and genotypic variation of the aphidSitobion avenaecollected from cereal crops in northern France were examined by analysing variation at five microsatellite loci across several years and seasons. Little regional and temporal differentiation was detected, as shown by very lowFSTamong populations. Repeated genotypes, significant heterozygote deficits, positiveFISvalues and frequent linkage disequilibria were found in nearly all samples, suggesting an overall pattern of reproductive mode variation inS. avenaepopulations. In addition, samples from Brittany (Bretagne) showed greater signs of asexual reproduction than those from the north of France, indicating a trend toward increasing sexuality northward. These patterns of reproductive variation inS. avenaeare consistent with theoretical models of selection of aphid reproductive modes by climate. Contrasting with little changes in allelic frequencies, genotypic composition varied substantially in time and, to a lesser extent, in space. An important part of changes in genotypic arrays was due to the variation in frequency distribution of common genotypes, i.e. those that were found at several instances in the samples. Genotypic composition was also shown to vary according to climate, as genotypic diversity in spring was significantly correlated with the severity of the previous winter and autumn. We propose that the genetic homogeneity amongS. avenaepopulations shown here across large temporal and spatial scales is the result of two forces: (i) migration conferred by high dispersal capabilities, and (ii) selection over millions of hectares of cereals (mostly wheat) bred from a narrow genetic base.
Characterization of the M918T sodium channel gene mutation associated with strong resistance to pyrethroid insecticides in the peach-potato aphid,Myzus persicae(Sulzer)
Authors: Eleftherianos I. , Foster S.P. , Williamson M.S. , Denholm I.
Published: December 2007

Recent advances in the characterisation of insect sodium channel gene sequences have identified a small number of point mutations within the channel protein that are implicated in conferring target-site resistance to pyrethroid insecticides (so-called knockdown resistance or kdr). The L1014F (leucine-to-phenylalanine) mutation located in the centre of segment 6 of the domain II region (IIS6) of the sodium channel (the so-called kdr trait) has been detected in the peach-potato aphid,Myzus persicae(Sulzer), and is considered to be the primary cause of pyrethroid resistance in this species. Here we report on the characterisation of a second mutation, M918T (methione-to-threonine), within the nearby IIS4–S5 intracellular linker (the so-called super-kdr trait) in a field clone also possessing L1014F, with both mutations present in heterozygous form. The resistance phenotype ofM. persicaeclones possessing various combinations of L1014F and M918T to a wide range of pyrethroids (both Type I and II) was assessed in leaf-dip bioassays and to lambda-cyhalothrin applied at up to ten times the recommended field rate as foliar sprays to aphids feeding on whole plants. Bioassay results demonstrated that presence of both mutations was associated with extreme resistance to all the pyrethroids tested relative to aphids lacking the mutations. Furthermore, this resistance well exceeded that shown by aphids that were homozygous for L1014F but lacking M918T. However, pre-treatment with piperonyl butoxide in the leaf-dip bioassays failed to suppress pyrethroid resistance in aphids carrying one or both of the mutations. The relevance of these findings for monitoring and managing pyrethroid resistance inM. persicaepopulations in the field is discussed.
An Economic Interpretation of the Constitutional Convention of 1787 Revisited
Authors: Heckelman Jac C. , Dougherty Keith L.
Published: December 2007

Empirical studies ofdelegatevoting at the Constitutional Convention have relied on the same 16 roll call votes. This article re-examines various assumptions used in the collection of these data. We first create a baseline regression. We then consider the effect of dropping delegates not in attendance, re-inferring the votes from primary sources, examining various subsamples of the roll calls, and reconstructing constituency variables to include state districts. Our findings suggest that personal interests were indeed important for decision making at the Constitutional Convention, but constituent interests were less important than previously claimed.
Running Out of Steam: Federal Inspection and Locomotive Safety, 1912–1940
Authors: Aldrich Mark
Published: December 2007

Locomotive inspection was among the most important Progressive Era federal workplace regulations. Inspection rules were enforced by a new Bureau of Locomotive Inspection, which claimed credit for subsequent safety improvements. Relying on published and unpublished data this article assesses these claims. Literary sources suggest that the bureau achieved compliance by emphasizing regulatory benefits and that its activities sharply reduced locomotive defects through the 1920s, in part by reducing agency problems. A model for 1923–1932 reinforces this conclusion, but suggests that the safety gains came at high cost. After 1932 safety improvements stagnated, for inspection ran out of steam.
Information Sharing During the Klondike Gold Rush
Authors: Allen Douglas W.
Published: December 2007

When George Carmack struck gold in the Yukon territory on 17 August 1896, he freely shared the details and started what would eventually be three waves of rushes. This reflected a social norm of the Klondike, namely that any miner who struck gold would share this information. Miners did not behave this way in other nineteenth-century gold rushes. The article's hypothesis is that the extreme mining conditions and local geography of the Yukon led to very secure property rights over mining claims. Therefore, it took only a small incentive payment to induce miners to act in the social interest.
Learning by Dying: Combat Performance in the Age of Sail
Authors: Benjamin Daniel K. , Tifrea Anca
Published: December 2007

Between 1660 and 1815 the combat fatality rate among British navy captains fell by 98 percent, even as the combat success of the British Navy rose dramatically. Both developments can be explained as a result of learning by doing among British commanders. This learning was importantly driven by the extensive wartime experience accumulated over this period, combined with the unparalleled financial incentives for combat success offered to British commanders.
The Burden of Early Exposure to Malaria in the United States, 1850–1860: Malnutrition and Immune Disorders
Authors: Hong Sok Chul
Published: December 2007

This article uses nineteenth-century evidence to calculate the impact of early exposure to malaria-ridden environments on nutritional status and the immune system in America. I estimate the risk of contracting malarial fevers in the 1850s by using correlations between malaria and environmental factors such as climate and geographical features. The study demonstrates that Union Army recruits who spent their early years in malaria-endemic counties were 1.1 inches shorter at enlistment due to malnutrition and were 13 percent more susceptible to infections during the U.S. Civil War as a result of immune disorders than were those from malaria-free regions.
Reproduction inStrongyloides(Nematoda): a life between sex and parthenogenesis
Authors: STREIT A.
Published: December 2007

Nematodes of the genusStrongyloidesparasitize the small intestines of vertebrates. In addition to a parasitic life-cycle, which is generally considered to be parthenogenetic,Strongyloidescan also have a facultative, free-living generation involving male and female worms. The purpose of the present article was to review the literature on the modes of reproduction, the routes of development in the two generations ofStrongyloides, discuss the controversial opinions in the literature regarding these aspects and point to new opportunities for addressing key questions in relation to the biology of reproduction of members of the genus employing genetic and genomic tools.
Characterization of highly concentrated serum lectins in spotted halibutVerasper variegatus
Authors: HATANAKA A. , UMEDA N. , HIRAZAWA N.
Published: December 2007

Mannose-binding lectins were purified from flatfish spotted halibut (Verasper variegatus) serum. These lectins, which we named VVL (Verasper variegatuslectin)-α (~33 kDa) and VVL-β (~30 kDa) (VVLs), under non-reducing SDS-PAGE, were surprisingly highly concentrated in serum (1·92±0·55 mg/ml;n=5), compared with other serum lectins. Both VVLs are heterodimers comprised of 2 types of subunit via inter-subunit disulfide bonds, and one subunit of VVL-α has a N-linked sugar chain. Based on N-terminal amino acid sequences, the nucleotide sequences of one subunit of VVL cDNAs were determined by 3′- and 5′-rapid amplification of the cDNA ends. The full-length VVL subunit cDNAs contained 489 bp, encoding an open reading frame of 163 amino acids. We found that VVLs bind to an ~8 kDa ciliary surface glycoprotein (a putative agglutination/immobilization antigen that we reported previously) of the fish parasiteNeobenedenia girellae, and agglutinate this parasitein vitro.
Parental mental illness and fatal birth defects in a national birth cohort
Authors: Webb R. T. , Pickles A. R. , King-Hele S. A. , Appleby L. , Mortensen P. B. , Abel K. M.
Published: December 2007

Background

Few large studies describe links between maternal mental illness and risk of major birth defect in offspring. Evidence is sparser still for how effects vary between maternal diagnoses and no previous study has assessed risk with paternal illnesses.

Method

A population-based birth cohort was created by linking Danish national registers. We identified all singleton live births during 1973–1998 (n=1.45 m), all parental psychiatric admissions from 1969 onwards, and all fatal birth defects until 1 January 1999. Linkage and case ascertainment were almost complete. Relative risks were estimated using Poisson regression.

Results

Risk of fatal birth defect was elevated in relation to history of any maternal admission and also with affective disorders specifically, although the strongest effect found was with maternal schizophrenia. The rate was more than doubled in this group compared to the general population [relative risk (RR) 2.34, 95% confidence interval (CI) 1.45–3.77], which also represented a significant excess risk compared with all other admitted maternal disorders (p=0.018). Risk of death from causes other than birth defect was no higher with schizophrenia than with other maternal conditions. There was no elevation in risk of fatal birth defect if the father was admitted with schizophrenia or any other psychiatric diagnosis.

Conclusions

There are many possible explanations for a higher risk of fatal birth defect with maternal schizophrenia and affective disorder. These include genetic effects directly linked with maternal illness, lifestyle factors (diet, smoking, alcohol and drugs), poor antenatal care, psychotropic medication toxicity, and gene–environment interactions. Further research is needed to elucidate the causal mechanisms.
Sky of blue, sea of green: a semiotic reading of the film Yellow Submarine
Authors: LETTS MARIANNE TATOM
Published: December 2007

The Beatles’ film Yellow Submarine (1968) reflects conflicts between conventional society, represented by classical music, and rebellious youth culture, represented by other musical types, such as folk and pop (subsumed under the term ‘vernacular’). Taking their inspiration from the song ‘Yellow Submarine’ (Revolver, 1966), the filmmakers created a narrative for a psychedelic ‘hero’s journey’ from existing Beatles songs. This article discusses how the musical codes that symbolise different groups are used to mediate between divergent elements in both the film and contemporary society, by referring to such elements beyond the film as the Beatles’ comprehensive body of songs (which in itself forms a kind of mythology) and cultural events of the time. In Yellow Submarine, the Blue Meanies imprison Pepperland by immobilising all producers of music, whether ‘classical’ (the string quartet led by the elderly Lord Mayor) or ‘vernacular’ (Sgt. Pepper’s Lonely Hearts Club Band). The Beatles are able to free Pepperland by manipulating and ultimately uniting the musical codes – an idealistic message for the ‘real world’ to heed.
Black, white and blue: the racial antagonism of The Smiths’ record
sleeves
Authors: WARNES ANDREW
Published: December 2007

As Matthew Bannister has recently suggested in these pages (see Popular Music, 25/1), The Smiths stand at the head of a 1980s Indie canon based on its rejection of a commodification associated with contemporary black US musics. This article argues that this racial understanding has also bled into the band’s critical reception, encouraging many to assume that Morrissey and Marr drew on exclusively white influences. Specifically, I argue that the white camp icons from the 1950s and 1960s who famously adorn the band’s record sleeves together form a kind of smokescreen, or ‘beard’, which stokes interest in Morrissey’s sexual predilections and orients it away from his and Marr’s Black Atlantic sources. The pre-immigrant Britain summoned up by these icons, I argue, helps prevent fans and critics alike from grasping that Morrissey’s lyrical attempts to find humour and succour by remembering pain is profoundly inspired by the African-American form of the Blues.
Cliff Richard’s self-presentation as a redeemer
Authors: LÖBERT ANJA
Published: December 2007

Although tremendously popular, Great Britain’s long-term icon Cliff Richard has been widely neglected by popular music studies. This article aims to correct this omission by introducing an argument that claims that Cliff Richard portrays himself to a considerable degree as a saviour figure. Evidence for this thesis will be drawn from three meaningful dimensions in popular music: song lyrics, pictorial self-representations, and image components. These three areas can be shown to be semantically concordant in presenting Cliff Richard as a redeemer. While the promise of redemption by the singer persona is a recurring motif in his song lyrics, this assurance gets repeated in pictorial representations that make allusions to Jesus Christ (through posture, lighting, and elevation) and is further reinforced by a number of components of Richard’s image such as the (apparently) incorruptible body, the asexuality, and the demonstrative benevolence towards the sick and poor. The combination of these sign-complexes creates a meaningful pattern around the singer that sets him apart as a surrogate saviour.
From market to non-market: An autonomous agent approach to central planning
Authors: GREENWOOD DAN
Published: December 2007

In the longstanding debate in political economy about the feasibility of socialism, the Austrian School of Economists have argued that markets are an indispensable means of evaluating goods, hence a prerequisite for productive efficiency. Socialist models for non-market economic calculation have been strongly influenced by the equilibrium model of neoclassical economics. The Austrians contend that these models overlook the essence of the calculation problem by assuming the availability of knowledge that can be acquired only through the market process itself. But the debate in political economy has not yet considered the recent emergence of agent-based systems and their applications to resource allocation problems. Agent-based simulations of market exchange offer a promising approach to fulfilling the dynamic functions of knowledge encapsulation and discovery that the Austrians show to be performed by markets. Further research is needed in order to develop an agent-based approach to the calculation problem, as it is formulated by the Austrians. Given that the macro-level objectives of agent-based systems can be easily engineered, they could even become a desirable alternative to the real markets that the Austrians favour.
Text-based domain ontology building using Tf-Idf and metric clusters techniques
Authors: REZGUI YACINE
Published: December 2007

The paper describes the methodology used to develop a construction domain ontology, taking into account the wealth of existing semantic resources in the sector ranging from dictionaries to thesauri. Given the characteristics and settings of the construction industry, a modular, architecture-centric approach was adopted to structure and develop the ontology. The paper argues that taxonomies provide an ideal backbone for any ontology project. Therefore, a construction industry standard taxonomy was used to provide the seeds of the ontology, enriched and expanded with additional concepts extracted from large discipline-oriented document bases using information retrieval (IR) techniques.
The usability of semantic search tools: a review
Authors: UREN VICTORIA , LEI YUANGUI , LOPEZ VANESSA , LIU HAIMING , MOTTA ENRICO , GIORDANINO MARINA
Published: December 2007

The goal of semantic search is to improve on traditional search methods by exploiting the semantic metadata. In this paper, we argue that supporting iterative and exploratory search modes is important to the usability of all search systems. We also identify the types of semantic queries the users need to make, the issues concerning the search environment and the problems that are intrinsic to semantic search in particular. We then review the four modes of user interaction in existing semantic search systems, namely keyword-based, form-based, view-based and natural language-based systems. Future development should focus on multimodal search systems, which exploit the advantages of more than one mode of interaction, and on developing the search systems that can search heterogeneous semantic metadata on the open semantic Web.
Influence of carbon‐nitrogen cycle coupling on land model response to CO2 fertilization and climate variability
Authors: Thornton Peter E. , Lamarque Jean‐François , Rosenbloom Nan A. , Mahowald Natalie M.
Published: December 2007

Nutrient cycling affects carbon uptake by the terrestrial biosphere and imposes controls on carbon cycle response to variation in temperature and precipitation, but nutrient cycling is ignored in most global coupled models of the carbon cycle and climate system. We demonstrate here that the inclusion of nutrient cycle dynamics, specifically the close coupling between carbon and nitrogen cycles, in a terrestrial biogeochemistry component of a global coupled climate system model leads to fundamentally altered behavior for several of the most critical feedback mechanisms operating between the land biosphere and the global climate system. Carbon‐nitrogen cycle coupling reduces the simulated global terrestrial carbon uptake response to increasing atmospheric CO2 concentration by 74%, relative to a carbon‐only counterpart model. Global integrated responses of net land carbon exchange to variation in temperature and precipitation are significantly damped by carbon‐nitrogen cycle coupling. The carbon cycle responses to temperature and precipitation variation are reduced in magnitude as atmospheric CO2 concentration rises for the coupled carbon‐nitrogen model, but increase in magnitude for the carbon‐only counterpart. Our results suggest that previous carbon‐only treatments of climate‐carbon cycle coupling likely overestimate the terrestrial biosphere's capacity to ameliorate atmospheric CO2 increases through direct fertilization. The next generation of coupled climate‐biogeochemistry model projections for future atmospheric CO2 concentration and climate change should include explicit, prognostic treatment of terrestrial carbon‐nitrogen cycle coupling.
Groundwater table mounding, pore pressure, and liquefaction induced by explosions: Energy‐distance relations
Authors: Charlie Wayne A. , Doehring Donald O.
Published: December 2007

Explosive‐induced ground motion can alter well water levels and induce liquefaction in water‐saturated cohesionless geological profiles. Analysis of underground detonations of chemical and nuclear explosives indicates that residual pore pressure and groundwater table mounding can be induced to maximum distances in meters equal to 0.087 J1/3or 14 kg1/3, a zone where the estimated peak compressive strain exceeds 0.007% and peak particle velocity exceeds 0.11 m/s. Liquefaction can be induced to maximum distances in meters equal to 0.019 J1/3or 3 kg1/3, a zone where the estimated peak compressive strain exceeds 0.07% and peak particle velocity exceeds 1.1 m/s. These relationships are linear over 11 orders of magnitude of energy (joules) or trinitrotoluene equivalent mass (kilograms). Maximum distances for residual pore pressure and liquefaction for surface explosions are about one third of those found for underground explosions.
On the dominance of changes in planetary angular momentum in large scale extra‐tropical flows
Authors: Rubin Shira , Paldor Nathan , Ziv Baruch
Published: December 2007

Considerations of the temporal changes in angular momentum are employed to diagnose air trajectories over large scale distances calculated from the publicly available global data base of NCEP/NCAR. It is shown that outside the Tropics both the total angular momentum and its Lagrangian (material) time‐derivative are dominated by the planetary term, regardless of the direction of the transport, whereas the contribution of the non‐linear term is always negligible. In the Tropics the planetary term and the acceleration terms alternately dominated the angular momentum evolution. These Lagrangian results are reinforced by Eulerian calculations of instantaneous maps of the relative contributions of the various terms in the evolution equation of the angular momentum. The simple equation of angular momentum evolution (compared to the more complex zonal momentum equation) is accurately satisfied by NCEP/NCAR re‐analyzed fields even over Africa, where the data for the reanalysis is scant. The only exceptions to the general dominance of the planetary term over the angular momentum evolution in the extra‐Tropics are along trough‐/ridge‐lines (where the flow changes direction sharply) and at the entrance/exit regions of straight jets, where the flow accelerates/decelerates.
Evaluation of a new mixed‐phase cloud microphysics parameterization with CAM3 single‐column model and M‐PACE observations
Authors: Liu Xiaohong , Xie Shaocheng , Ghan Steven J.
Published: December 2007

Most global climate models generally prescribe the partitioning of condensed water into cloud droplets and cloud ice in mixed‐phase clouds according to a temperature‐dependent function, which affects modeled cloud phase, cloud lifetime and radiative properties. This study evaluates a new mixed‐phase cloud microphysics parameterization (for ice nucleation and water vapor deposition) against the Atmospheric Radiation Measurement (ARM) Mixed‐phase Arctic Cloud Experiment (M‐PACE) observations using the NCAR Community Atmospheric Model Version 3 (CAM3) single column model (SCAM). It is shown that SCAM with the new scheme produces a more realistic simulation of the cloud phase structure and the partitioning of condensed water into liquid droplets against observations during the M‐PACE than the standard SCAM. A sensitivity test indicates that ice number concentration could play an important role in the simulated mixed‐phase cloud microphysics, and therefore needs to be realistically represented in global climate models.
Historical reconstruction of the Atlantic Meridional Overturning Circulation from the ECMWF operational ocean reanalysis
Authors: Balmaseda Magdalena A. , Smith Gregory C. , Haines Keith , Anderson David , Palmer T. N. , Vidard Arthur
Published: December 2007

A reconstruction of the Atlantic Meridional Overturning Circulation (MOC) for the period 1959–2006 has been derived from the ECMWF operational ocean reanalysis. The reconstruction shows a wide range of time‐variability, including a downward trend. At 26N, both the MOC intensity and changes in its vertical structure are in good agreement with previous estimates based on trans‐Atlantic surveys. At 50N, the MOC and strength of the subpolar gyre are correlated at interannual time scales, but show opposite secular trends. Heat transport variability is highly correlated with the MOC but shows a smaller trend due to the warming of the upper ocean, which partially compensates for the weakening of the circulation. Results from sensitivity experiments show that although the time‐varying upper boundary forcing provides useful MOC information, the sequential assimilation of ocean data further improves the MOC estimation by increasing both the mean and the time variability.
Potential for airborne offbeam lidar measurements of snow and sea ice thickness
Authors: Várnai Tamás , Cahalan Robert F.
Published: December 2007

This article discusses the capabilities and limitations of a new approach to airborne measurements of snow and sea ice thickness. Such measurements can help better understand snow and sea ice processes and can also contribute to the validation of satellite measurements. The approach discussed here determines physical snow and sea ice thickness by observing the horizontal spread of lidar pulses: The bright halo observed around an illuminated spot extends farther out in thicker layers because photons can travel longer without escaping through the bottom. Since earlier studies suggested the possibility of such sea ice retrievals, this article presents a theoretical analysis of additional uncertainties that arise in airborne observations of snow and sea ice. Snow and sea ice retrievals pose somewhat different challenges because while sea ice is usually much thicker, snow contains a much higher concentration of scatterers. As a result, sea ice halos are larger, but snow halos are brighter. The results indicate that airborne sea ice retrievals are possible at night and that snow retrievals are possible during both night and day. For snow thicknesses less than about 50 cm, observational issues, such as calibration uncertainty, can cause retrieval uncertainties on the order of 10% in 1‐km‐resolution retrievals. For moderate snow and sea ice thicknesses (<30 cm and 3 m, respectively), these issues cause similar (∼10%) uncertainties in sea ice thickness retrievals as well. These results indicate that offbeam lidars have the potential to become an important component of future snow and sea ice observing systems.
Tropical Atlantic convection as revealed by ozone and relative humidity measurements
Authors: Kley Dieter , Smit Herman G. J. , Nawrath Susanne , Luo Zhengzhao , Nedelec Philippe , Johnson Richard H.
Published: December 2007

Properties of deep convection over the tropical central Atlantic are analyzed in light of ozone as a quasi‐conservative quantity on the convective timescale. Multiple years of measurements of ozone from aircraft, shipboard and balloon platforms reveal that the mean ozone mixing ratio near 250 hPa, close in time and distance to the convective outflow at that pressure, is 7 ppb higher than at sea surface and marine boundary layer (MBL). The process that increases the ozone mixing ratio in the convective outflow is shown to be lateral entrainment of higher value ozone mixing ratio originating from the subsiding branch of the Hadley Cell. Ozone and humidity soundings obtained from cruise campaigns over the same region are used to identify the preferred or most pronounced levels of entrainment, which appear to be near 700 hPa and from 500 to 400 hPa, as indicated by layers of simultaneous drying and enhanced ozone mixing ratio in otherwise smooth profiles. There are also indications of convective detrainment at around 600 hPa and 300 hPa, which may correspond to shallow and deep convection, respectively. A simple model is used to estimate the ratio of the bulk entrainment mass flux (Φ2) between 900 and 400 hPa to the convective mass flux from the MBL below (Φ1). The ratio is calculated, on the basis of climatological ozone measurements, to be Φ2/Φ1 = 0.50. Thus the bulk outflow is 50% larger than the lateral mass flux in the MBL. The relative humidity over ice (RHi) of air at the convective outflow is centered at RHi = 110%, with a considerable range from a low near 40% to a high near 150%.
Remote sensing of Greenland ice sheet using multispectral near‐infrared and visible radiances
Authors: Chylek Petr , McCabe M. , Dubey M. K. , Dozier J.
Published: December 2007

We present the physical basis of and validate a new remote‐sensing algorithm that utilizes reflected visible and near‐infrared radiation to discriminate between dry and wet snow. When applied to the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data, our discrimination algorithm has the potential to retrieve melting regions of the ice sheet at a spatial resolution of 0.25 km2, over three orders of magnitude higher than the resolution of current microwave methods. The method should be useful for long‐term monitoring of the melt area of the Greenland ice sheet, especially regions close to ice sheet margins and of the outflow glaciers. Our analysis of MODIS retrievals of the western portion of the Greenland ice sheet over the period 2000 to 2006 indicates significant interannual variability with a maximum melt extent in 2005. Collocated in situ meteorological data reveal a high correlation (0.80) between the MODIS melt‐day area and the average summer temperature. Our analysis suggests that it is the magnitude of the summer temperature that dominates the melting (not the variability of the length of the melting season). Furthermore, we find that the melt‐day area increases by about 3.8% for each 0.1 K increase in the average surface air summer temperature. We combine this empirical relationship with historic temperature data to infer that the melt‐day area of the western part of the ice sheet doubled between the mid‐1990s and mid‐2000s and that the largest ice sheet surface melting probably occurred between 1920s and 1930s, concurrent with the warming in that period.
Data assimilation of incoherent scatter radar observation into a one‐dimensional midlatitude ionospheric model by applying ensemble Kalman filter
Authors: Yue Xinan , Wan Weixing , Liu Libo , Zheng Fei , Lei Jiuhou , Zhao Biqiang , Xu Guirong , Zhang Shun‐Rong , Zhu Jiang
Published: December 2007

In this paper, electron densities during 25–28 September 2000 observed by the Millstone Hill incoherent scatter radar (ISR) are assimilated into a one‐dimensional midlatitude ionospheric theoretical model by using an ensemble Kalman filter (EnKF) technique. It is found that (1) the derived vertical correlation coefficients of electron density show obvious altitude dependence. These variations are consistent with those from ISR observations. (2) The EnKF technique has a better performance than the 3DVAR technique especially in the data‐gap regions, which indicates that the EnKF technique can extend the influences of observations from data‐rich regions to data‐gap regions more effectively. (3) Both the altitude and local time variations of the root mean square error (RMSE) of electron densities for the ensemble spread and ensemble mean from observation behave similarly. It is shown that the spread of the ensemble members can represent the deviations of ensemble mean from observations. (4) To achieve a better prediction performance, the external driving forces should also be adjusted simultaneously to the real weather conditions. For example, the performance of prediction can be improved by adjusting neutral meridional wind using equivalent wind method. (5) In the EnKF, there are often erroneous correlations over large distance because of the sampling error. This problem may be avoided by using a relative larger ensemble size.
Indosinian high‐strain deformation for the Yunkaidashan tectonic belt, south China: Kinematics and40Ar/39Ar geochronological constraints
Authors: Wang Yuejun , Fan Weiming , Cawood Peter A. , Ji Shaocheng , Peng Touping , Chen Xinyue
Published: December 2007

Structural and40Ar/39Ar data from the Yunkaidashan Belt document kinematic and tectonothermal characteristics of early Mesozoic Indosinian orogenesis in the southern part of the South China Block. The Yunkaidashan Belt is tectonically divided from east to west into the Wuchuang‐Sihui shear zone, Xinyi‐Gaozhou block, and the Fengshan‐Qinxi shear zone. Indosinian structural elements ascribed to the Indosinian orogeny include D2and D3deformation. The early D2phase is characterized by folding and thrusting with associated foliation and lineation development, related to NW‐SE transpression under amphibolite‐ to greenschist‐facies conditions. This event is heterogeneously overprinted by D3deformation characterized by a gentle‐dipping S3foliation, subhorizontally to shallowly plunging L3lineation, some reactived‐D2folds and low‐angle normal faults. The D3fabrics suggest a sinistral transtensional regime under greenschist‐facies metamorphism. The timing of the D2and D3events have been constrained to the early to middle Triassic (∼248–220 Ma) and late Triassic (∼220–200 Ma) respectively on the basis of40Ar/39Ar geochronology and regional geological relations. The change from oblique thrusting (D2) to sinistral transtension (D3) may reflect oblique convergence and crustal thickening followed by relaxation of the overthickened crust. In combination with the regional relations from Xuefengshan to Yunkaidashan and on to Wuyishan, the early phase of the Indosinian orogeny constituted a large‐scale positive flower structure and is related to the intracontinental convergence during the assembly of Pangea in which the less competent South China Orogen was squeezed between the more competent North China and Indosinian Blocks.
Kinetic analysis of butyrate transport in human colon adenocarcinoma cells reveals two different carrier-mediated mechanisms
Authors: Lecona Emilio , Olmo Nieves , Turnay Javier , Santiago-Gómez Angélica , López de Silanes Isabel , Gorospe Myriam , Lizarbe M. Antonia
Published: December 2007

Butyrate has antitumorigenic effects on colon cancer cells, inhibits cell growth and promotes differentiation and apoptosis. These effects depend on its intracellular concentration, which is regulated by its transport. We have analysed butyrate uptake kinetics in human colon adenocarcinoma cells sensitive to the apoptotic effects of butyrate (BCS-TC2, Caco-2 and HT-29), in butyrate-resistant cells (BCS-TC2.BR2) and in normal colonic cells (FHC). The properties of transport were analysed with structural analogues, specific inhibitors and different bicarbonate and sodium concentrations. Two carrier-mediated mechanisms were detected: a low-affinity/high-capacity (Km=109±16 mM in BCS-TC2 cells) anion exchanger and a high-affinity/low-capacity (Km=17.9±4.0 μM in BCS-TC2 cells) proton–monocarboxylate co-transporter that was energy-dependent and activated via PKCδ (protein kinase Cδ). All adenocarcinoma cells analysed express MCT (monocarboxylate transporter) 1, MCT4, ancillary protein CD147 and AE2 (anion exchanger 2). Silencing experiments show that MCT1, whose expression increases with butyrate treatment in butyrate-sensitive cells, plays a key role in high-affinity transport. Low-affinity uptake was mediated by a butyrate/bicarbonate antiporter along with a possible contribution of AE2 and MCT4. Butyrate treatment increased uptake in a time- and dose-dependent manner in butyrate-sensitive but not in butyrate-resistant cells. The two butyrate-uptake activities in human colon adenocarcinoma cells enable butyrate transport at different physiological conditions to maintain cell functionality. The high-affinity/low-capacity transport functions under low butyrate concentrations and may be relevant for the survival of carcinoma cells in tumour regions with low glucose and butyrate availability as well as for the normal physiology of colonocytes.
The covalent modification and regulation of TLR8 in HEK-293 cells stimulated with imidazoquinoline agonists
Authors: Rajagopal Raj , Waller Andrew S. , Mendoza James D. , Wightman Paul D.
Published: December 2007

The mammalian TLRs (Toll-like receptors) mediate the rapid initial immune response to pathogens through recognition of pathogen-associated molecular patterns. The pathogen pattern to which TLR8 responds is ssRNA (single-stranded RNA) commonly associated with ssRNA viruses. TLR8 also responds to small, purine-like molecules including the imidazoquinoline IRMs (immune-response modifiers). The IRMs include molecules that selectively activate TLR7, selectively activate TLR8 or non-selectively activate both TLR7 and TLR8. Using HEK-293 cells (human embryonic kidney cells) stably expressing an NF-κB (nuclear factor κB)/luciferase promoter-reporter system as a model system, we have examined the regulation of TLR8 using the non-selective TLR7/8 agonist, 3M-003. Using conservative tyrosine to phenylalanine site-directed mutation, we show that of the 13 tyrosine residues resident in the cytosolic domain of TLR8, only three appear to be critical to TLR8 signalling. Two of these, Tyr898 and Tyr904, reside in the Box 1 motif and the third, Tyr1048, lies in a YXXM putative p85-binding motif. TLR8 is tyrosine-phosphorylated following 3M-003 treatment and TLR8 signalling is inhibited by tyrosine kinase inhibitors. Treatment with 3M-003 results in the association of the p85 regulatory subunit of PI3K (phosphoinositide 3-kinase) with TLR8 and this association is inhibited by tyrosine to phenylalanine mutation of either the YXXM or Box 1 motifs. As a further consequence of activation by 3M-003, TLR8 is modified to yield both higher and lower molecular mass species. These species include a monoubiquitinated form as deduced from ubiquitin peptide sequencing by HPLC/MS/MS (tandem MS).