bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Study on Electrical and Microstructural Characteristics of ZrO2 and HfO2 Grown by Atomic Layer Deposition
Authors: Kim Hyoungsub , Saraswat Krishna C. , McIntyre Paul C.
Published: November 2005

Ultra-thin ZrO2 and HfO2 dielectric films grown by atomic layer deposition (ALD) are quite promising materials for gate dielectric applications in future transistors, and they exhibit significantly different as-grown microstructures: polycrystalline and amorphous phases, respectively. However, under the identical deposition conditions, both metal oxides show surprisingly similar capacitance–voltage (C–V) characteristics as a function of film thickness, implying that the identities and densities of fixed charge and bulk trapping charge are similar. Factors other than the film microstructure, such as concentration of impurities incorporated during the film deposition, are believed predominantly to control important C–V characteristics. Only the dielectric constant appears to depend significantly on the identity of the dielectric material. It is found that the dielectric constant of ALD-HfO2 (∼20) is significantly lower than that of ZrO2 (∼30) due to the differences in microstructure and also atomic density of the film. In terms of the leakage current characteristics, the effective potential barrier heights between Pt and these two dielectric films are identical (∼2.3 eV) within the experimental uncertainty. Implications for the electrode/dielectric interface electronic structure are discussed.
In Vitro and In Vivo Inhibition of Skin Matrix Metalloproteinases by Pothomorphe umbellata Root Extract
Authors: Ropke Cristina D. , da Silva Vanessa V. , Kera Clarissa Z. , Miranda Denise V. , de Almeida Rebeca L. , Sawada Tâia C. H. , Barros Silvia B. M.
Published: November 2005

Exposure to UV radiation up‐regulates the synthesis of matrix metalloproteinases (MMPs), a group of matrix‐degrading enzymes. MMPs are regarded as promising therapeutic targets and the development of effective inhibitors is an important research focus. The plant Pothomorphe umbellata has been shown to exert a potent antioxidant activity on the skin and to delay the onset and reduce the incidence of UVB‐induced chronic skin damage. The aim of the present study was to determine the effect of P. umbellata ethanolic root extract on MMP‐2 and MMP‐9. The in vitro inhibition of MMP‐2 and MMP‐9 was measured by gelatin zymography in the presence of different concentrations of P. umbellata extract, as well as in the presence of its isolated active principle 4‐nerolidylcatechol (4‐NC). The inhibitory effect of the P. umbellata extract was stronger than that of 4‐NC. Gelatin zymography and histo‐logical analysis revealed that P. umbellata was able to inhibit constitutive MMP‐9 activity in vivo in mice sacrificed 2 h after UVB irradiation. The intensity of the MMP‐2 band was unchanged. Our data contribute to the elucidation of the mechanism of prevention of photoaging by P. umbellata and may provide a rational basis for the use of this plant in prophylaxis against and treatment of skin cancer.
A sensitivity study of parameters used in shrinkage and creep prediction models
Authors: Howells R. W. , Lark R. J. , Barr B. I. G.
Published: November 2005

Over the last 15 years, there have been numerous models put forward for the prediction of the time-dependent behaviour of concrete and consequently concrete structures. The development of these models from a number of different sources has meant that the engineer now has a choice to make when undertaking creep and shrinkage prediction and it is difficult to know which is best suited for this purpose. Some are considerably more complex than others requiring greater amounts of input focusing on material data, concrete properties, environmental conditions, specimen geometry and loading conditions. The study reported here focuses on the sensitivity to change, in both the short term and over time, of the individual parameters that comprise the input and whether one model is more appropriate in any given situation. It has been found that for each model certain parameters are more sensitive than others. It is suggested that for any given model, the parameters that do not reflect the expected behaviour when changed counterbalance each other, cancelling out any errors. This further suggests that when deciding on which model to use when predicting shrinkage and creep strains it is prudent to look at the specific conditions that prevail, assess the relevant input parameters for which data are available, assess the sensitivity level of each of these parameters and then make a decision as to the most appropriate model to use.
Cracking and deformation of axially reinforced members subjected to pure tension
Authors: Beeby A. W. , Scott R. H.
Published: November 2005

This paper describes work carried out as part of a major experimental and theoretical investigation into tension stiffening. This work was carried out at the universities of Leeds and Durham. The experimental work enabled a detailed study to be undertaken of the behaviour of concrete in tension surrounding reinforcing bars. This study showed that a more-or-less linear variation in concrete and steel stress occurred in the region affected by a crack and also that behaviour of the concrete in the region of a crack remained substantially elastic. The experimental study permitted equations to be developed to predict the deformations and crack widths in axially reinforced tension members. Tests of the formulae for crack widths are reported and the formulae are shown to be satisfactory. A more detailed model of the behaviour in the region of a crack is proposed and shown to be reasonable.
Effect of Sodium Alendronate on Alveolar Bone Resorption in Experimental Periodontitis in Rats
Authors: Menezes Adriana M.A. , Rocha Francisco Airton C. , Chaves Hellíada V. , Carvalho Cibele B.M. , Ribeiro Ronaldo A. , Brito Gerly Anne C.
Published: November 2005

Background: Bisphosphonates are potent inhibitors of bone resorption and were shown to inhibit bone resorption in experimental periodontitis by unknown mechanisms. We studied the effect of the aminobisphosphonate sodium alendronate (SA) in experimental periodontitis. Wistar rats were subjected to ligature placement around the second upper left molars.

Methods: Animals were treated with SA 0.01 to 0.25 mg/kg subcutaneously (sc), either 1 hour before (prophylactic) or starting 5 days after (therapeutic) periodontitis induction and daily until the rats were sacrificed (11 days). Controls received saline. Animals were weighed daily. Alveolar bone loss was measured as the difference (in millimeters) between the cusp tip and the alveolar bone. The periodontium and the surrounding gingivae were examined at histopathology, and the neutrophil influx into the gingivae was assayed using myeloperoxidase activity. The local bacterial flora was assessed through culture of the gingival tissue in standard aerobic and anaerobic media.

Results: Alveolar bone loss was significantly and dose dependently inhibited by SA either as a prophylactic or therapeutic treatment compared to the control. SA reduced tissue lesion at histopathology, with partial preservation of the periodontium, coupled to decreased myeloperoxidase activity compared to the control. The reduced neutrophil influx was also shown in carrageenan‐induced peritonitis, used as a control experiment for this parameter. SA also significantly inhibited the growth of pigmented bacilli and Fusobacterium nucleatum, which are important in the pathogenesis of periodontal disease. SA also inhibited the in vitro growth of isolated Peptostreptococcus sp.

Conclusion: Sodium alendronate preserves alveolar bone resorption and has anti‐inflammatory and antibacterial activities in experimental periodontitis.
Can plants betray the presence of multiple herbivore species to predators and parasitoids? The role of learning in phytochemical information networks
Authors: Takabayashi Junji , Sabelis Maurice W. , Janssen Arne , Shiojiri Kaori , van Wijk Michiel
Published: November 2005

In response to feeding by phytophagous arthropods, plants emit volatile chemicals. This is shown to be an active physiological response of the plant and the released chemicals are therefore called herbivore‐induced plant volatiles (HIPV). One of the supposed functions of HIPV for the plant is to attract carnivorous natural enemies of herbivores. Depending on which plant and herbivore species interact, blends of HIPV show qualitative and quantitative variation. Hence, one may ask whether this allows the natural enemies to discriminate between volatiles from plants infested by herbivore species that are either suitable or unsuitable as a food source for the natural enemy. Another question is whether natural enemies can also recognise HIPV when two or more herbivore species that differ in suitability as a food source simultaneously attack the same plant species. By reviewing the literature we show that arthropod predators and parasitoids can tell different HIPV blends apart in several cases of single plant–single herbivore systems and even in single plant–multiple herbivore systems. Yet, there are also cases where predators and parasitoids do not discriminate or discriminate only after having learned the association between HIPV and herbivores that are either suitable or non‐suitable as a source of food. In this case, suitable herbivores may profit from colonising plants that are already infested by another non‐suitable herbivore. The resulting temporal or partial refuge may have important population dynamical consequences, as such refuges have been shown to stabilise otherwise unstable predator–prey models of the Lotka‐Volterra or Nicholson‐Bailey type.
The prevalence of self‐reported health problems and haemoglobin status of Sudanese adolescents
Authors: Moukhyer M.E. , de Vries N.K. , Bosma H. , van Eijk J.Th.M.
Published: November 2005

In this paper we describe self‐reported health problems and haemoglobin status among 1200 Sudanese adolescents (53.2% females, 46.8% males). Many adolescents report their general health as excellent and good (84%). A large number, however, report separate physical and psychological complaints. Report of psychological complaints is equal for both gender, and more psychological problems are reported with increasing age. Females and age groups 13–15 more often report chronic diseases. Malaria consistently has a relatively high prevalence. The overall prevalence of anaemia in our study is 32% (46.9% males, 19.2% females). The findings in our study do not sustain the traditional assumption that adolescence is a healthy period in human life. Implications for Sudanese health policies are discussed.
Physico-chemical characterization of the benthic environment of the Golfo San Jorge, Argentina
Authors: Fernández M. , Carreto J.I. , Mora J. , Roux A.
Published: November 2005

The benthic system of the Golfo San Jorge was characterized from physico-chemical parameters based on samplings obtained during seasonal research cruises carried out on board the INIDEP vessels from springtime 1999 through wintertime 2000. Spatial and seasonal variations of temperature, salinity, density, oxygen content and chlorophyll-a in bottom water and concentration of total organic matter, total organic carbon, total nitrogen, chlorophyll-a and phaeopigments in sediments were analysed. The origin and nutritional value of the deposited organic matter were also assessed. The behaviour of the physico-chemical characteristics of the benthic habitat, studied applying statistical techniques, defined three sectors with particular characteristics and minimum seasonal variations: sector 1, the largest and deepest one, comprises the central area of the gulf and corresponds to a depositional environment; sector 2 comprises the areas next to the extremes of the gulf and corresponds to a flow or erosive environment; sector 3 includes the coastal area and south-east part of the gulf and belongs to a transitional environment.
Using historical data to detect temporal changes in the abundances of intertidal species on Irish shores
Authors: Simkanin Christina , Power Anne Marie , Myers Alan , McGrath David , Southward Alan , Mieszkowska Nova , Leaper Rebecca , O'Riordan Ruth
Published: November 2005

An historical data set, collected in 1958 by Southward and Crisp, was used as a baseline for detecting change in the abundances of species in the rocky intertidal of Ireland. In 2003, the abundances of each of 27 species was assessed using the same methodologies (ACFOR [which stands for the categories: abundant, common, frequent, occasional and rare] abundance scales) at 63 shores examined in the historical study. Comparison of the ACFOR data over a 45-year period, between the historical survey and re-survey, showed statistically significant changes in the abundances of 12 of the 27 species examined. Two species (one classed as northern and one introduced) increased significantly in abundance while ten species (five classed as northern, one classed as southern and four broadly distributed) decreased in abundance. The possible reasons for the changes in species abundances were assessed not only in the context of anthropogenic effects, such as climate change and commercial exploitation, but also of operator error. The error or differences recorded among operators (i.e. research scientists) when assessing species abundance using ACFOR categories was quantified on four shores. Significant change detected in three of the 12 species fell within the margin of operator error. This effect of operator may have also contributed to the results of no change in the other 15 species between the two census periods. It was not possible to determine the effect of operator on our results, which can increase the occurrence of a false positive (Type 1) or of a false negative (Type 2) outcome.
Sponge fauna associated with a Mediterranean deep-sea coral bank
Authors: Longo Caterina , Mastrototaro Francesco , Corriero Giuseppe
Published: November 2005

Thirty species of sponges (29 Demospongiae, 1 Hexactinellida) have been recorded in association with a white coral bank situated off Cape S. Maria di Leuca (southern Italy) at depths ranging from 430 to 1160 metres. Notwithstanding the occurrence of clearly eurybathic species, two depth-dependent sponge groups can be identified along the bathymetric gradient. Two species, Geodia nodastrella and Plocamiopsis signata, are reported for the first time from the Mediterranean Sea. The sponge assemblage shows a higher affinity with the fauna from the Boreal region, with very low number of Mediterranean endemic species. Systematic notes concerning the poorly known and intriguing species, studied using scanning electron microscopy analysis, are reported.
Resurrection of Desmoxya (Porifera: Halichondrida), with the description of a new species from Rockall Bank bathyal coral reefs, North Atlantic
Authors: van Soest Rob W.M. , Hooper John N.A.
Published: November 2005

The genus Desmoxya Hallmann, 1917, erected for south-east Australian Higginsia lunata Carter, 1885, was assigned to the synonymy of Higginsia Higgin, 1877 (Porifera: Halichondrida) by the latest revision of the taxonomy of the Porifera (Hooper & van Soest, 2002). The discovery of an undescribed species living in the bathyal reefs of the North Atlantic Rockall Bank with characters closely similar to H. lunata justifies the resurrection of Desmoxya. Accordingly the North Atlantic material is described as a new species in Desmoxya, viz. D. pelagiae sp. nov. The new species differs from its Australian congener in habit (smooth thin crusts vs massive with digitiform processes) and spicule sizes (smaller megascleres, twice-sized acanthoxeas and single vs two sizes of trichodragmas). A probable third member of this genus is Higginsia anfractuosa Hooper & Lévi, 1993, described from shallow-water reefs near New Caledonia. For reasons of priority the name of the family to which Higginsia and Desmoxya are assigned needs to be changed from Desmoxyidae Hallmann, 1917 to Heteroxyidae Dendy, 1905, as this senior synonym was overlooked when Heteroxya was assigned to the same family as Higginsia and Desmoxya in Hooper & van Soest, 2002.
Evidence of a geographical variation in Mesochaetopterus (Polychaeta: Chaetopteridae) from the Pacific Ocean
Authors: Bhaud Michel R.
Published: November 2005

Specimens of Mesochaetopterus (Chaetopteridae) from seven geographical sources in the Pacific Ocean are compared on the basis of their hard structures: specialized chaetae, uncinal plates and tubes. There geographical variations are investigated both locally (New South Wales and the Solomon Islands) and over the whole Pacific Ocean from Australia (New South Wales) through the Solomon Islands to Galapagos and Hawaii. The most interesting result is the existence of intra-regional morphological variations with the hard structures differing on specimens sampled in two areas from New South Wales or in two areas from the Solomon Islands out of a total of three areas. These newly described morphologies imply that M. minutus, isolated in a first step from M. sagittarius and confined to the Pacific, is a pseudo-sibling species complex. Each element of this complex is morphologically distinguishable. Consequently the generally accepted role of the long-lived planktonic larvae characteristic of Mesochaetopterus, as a source of geographical homogeneity must be re-examined.
Reproductive biology of the deep-sea polychaete Gorgoniapolynoe caeciliae (Polynoidae), a commensal species associated with octocorals
Authors: Eckelbarger K.J. , Watling L. , Fournier Heidi
Published: November 2005

Some aspects of the reproductive biology of the polychaete Gorgoniapolynoe caeciliae have been described for the first time. Gorgoniapolynoe caeciliae is a deep-sea commensal species associated with Candidella imbricata, an octocoral that populates the New England Seamount chain. Gorgoniapolynoe caeciliae is a dioecious species with an equal sex ratio and fertile segments throughout most of the adult body. The gonads of both sexes are associated with genital blood vessels emerging from the posterior surface of most intersegmental septa. In the female, oogenesis is intraovarian with oocytes being retained within the ovary until vitellogenesis is completed. The largest female examined contained over 3000 eggs with a maximum diameter of 80–90 μm. In the male, the testes are repeated in numerous segments and consist of small clusters of spermatogonia, spermatocytes, and early spermatids associated with the walls of the genital blood vessels. Early spermatids are shed into the coelom where they complete differentiation into mature ect-aquasperm with a spherical head (4 μm), a small cap-like acrosome, and a short mid-piece with four mitochondria. Indirect evidence suggests that this species is an annual breeder that releases its gametes into seawater and produces a planktotrophic larva following fertilization. The reproductive biology of G. caeciliae is consistent with that of most other polynoids including many shallow water species suggesting that phylogenetic history strongly shapes its biology.
Still alive? Fine structure of the barrels made by Phronima (Crustacea: Amphipoda)
Authors: Hirose Euichi , Aoki Masakazu N. , Nishikawa Jun
Published: November 2005

Amphipods of the genus Phronima are known to make a barrel-shaped house from the gelatinous matrix of pelagic tunicates or siphonophores. Among the seven barrels examined here, one barrel of Phronima curvipes was supposed to be made from a swimming bell of a siphonophore based on its morphology, while the other six barrels made by P. sedentaria were immunochemically and/or morphologically identified as tunicates (i.e. Thetys vagina, other salps and pyrosomas). Histological observation showed that the phronimids had completely eaten the animal tissues other than the gelatinous matrix (i.e. tunic or mesoglea). Tunic cells were found in the tunicate barrel and some were probably tunic phagocytes that appeared to be alive and functional. In the tunicate barrels, cuticular layers of the tunic were found on both the outer and inner side of the barrel wall. Tunic cuticle would be regenerated on the inner side after the epidermis was grazed by the phronimids. The cuticular layers would protect the tunic matrix from the invasion of microorganisms. In the barrel supposed to originate from Thetys vagina, there are minute protrusions on the tunic cuticle as found in the intact tunic of this species. In the barrel from a siphonophore, neither cells nor cuticle regeneration were found. No bacteria were observed in the barrel, suggesting that the barrel has some antibiotic system.
Synisoma albertoi, a new species from the Strait of Gibraltar (southern Spain) with a key to known species of the genus (Crustacea: Isopoda: Idoteidae)
Authors: Castellanos Carolina , Junoy Juan
Published: November 2005

Synisoma albertoi sp. nov. (Isopoda: Valvifera: Idoteidae), is described and illustrated from specimens collected in the Strait of Gibraltar (southern Spain). The new species can be distinguished from all other species of the genus, with the exception of S. bellonae and S. raqueliae, by the fusion of the flagellar articles of the antenna. It is easily distinguishable from both S. bellonae and S. raqueliae by the presence of a tubercle on the cephalon; these three species also differ in the morphology of pleotelson, pereopods and appendix masculina. A key to the known species of Synisoma is provided.
Redescription of Lindia gravitata with comments on L. tecusa (Rotifera: Monogononta: Lindiidae)
Authors: De Smet Willem H.
Published: November 2005

Lindia gravitata, previously considered a synonym of L. tecusa by several authors is redescribed. Body shape and trophi structure show that both species are closely related, and unequivocally differentiated by e.g. toe shape, number of sensory papillae, and shape of subunci and epipharynx. Other related, but insufficiently described congeners are listed. The diagnostic features of the subgenus Halolindia are discussed.
Responses of gastropods to changes in amounts of leaf litter and algae in mangrove forests
Authors: Chapman M.G. , Michie K. , Lasiak T.
Published: November 2005

Leaf litter, pneumatophores, saplings and patches of macro-algae are common characteristics of habitats in mangrove forests. The amounts of these vary among different parts of mangrove forests. In Port Jackson, some parts of forests under the canopy of trees appeared to have more saplings, longer pneumatophores and greater amounts of leaf litter and macro-algae than did other similarly shaded parts of the forest. The former also appeared to have greater densities of snails, Ophicardelus spp. and Salinator solida, which was confirmed by quantitative sampling. Two field experiments were carried out, in which the amount of litter or algae and the length of the pneumatophores, were manipulated to test six alternative models about influences of these features of habitat that might explain these patterns. In each experiment, both species decreased rapidly in plots with reduced litter and showed no response to the length of the pneumatophores. In the first experiment, there was no response to reductions of algae, but in the second experiment, each species showed a decrease in density when algae were reduced. The implications of these rapid responses to changes in small-scale features of habitat are discussed with respect to managing disturbed habitats.
Parasitism as a potential contributor to massive clam mortality at the Blake Ridge Diapir methane-hydrate seep
Authors: Mills Anne M. , Ward Megan E. , Heyl Taylor P. , Van Dover Cindy L.
Published: November 2005

Vesicomyid clam species are abundant in many deep-sea chemosynthetic communities, including cold seeps. They rely primarily on thiotrophic (sulphide-oxidizing) gill symbionts for nutrition and thus require sulphide-rich environments. Submersible surveys of megafaunal distributions at the Blake Ridge Diapir, a deep-sea methane-hydrate seep located ∼200 miles off the coast of Charleston, South Carolina, documented massive mortalities of vesicomyid clams. The cause of these mortalities is unknown, but sulphide deprivation, sulphide toxicity, and disease are possible agents of mortality in this system. Similar redox profiles in sediment cores from live and dead clam beds do not support the hypothesis that there has been a transient shift in the flux of sulphide. To address the potential for disease as a cause of mortality, we undertook a histological survey of microparasites and other indications of disease in clam tissues. Six morphological types of parasites were identified using light microscopy, including two viral-like inclusions, Rickettsia-like gill inclusions, possible bacterial gut inclusions, bacterial gill infections, and a protistan inclusion. Of these parasites, two were pathogenic: viral-like inclusions in mantle tissues caused tissue degradation; bacterial gill infections resulted in localized disruption and degradation of gill filaments. Infection prevalence and densities were low for all parasites observed. The majority of clams examined showed intense haemocytic responses in the absence of any obvious etiologic agent, suggesting the presence of parasites not detectable by our methods. Our findings indicate that the clam population at the Blake Ridge seep was in relatively good health at the time of sampling.
Feeding and predation impact of chaetognaths in the north Aegean Sea (Strymonikos and Ierissos Gulfs)
Authors: Kehayias George , Michaloudi Evangelia , Koutrakis Emmanuil
Published: November 2005

The feeding of the most important chaetognath species (Sagitta enflata, Sagitta minima, Sagitta setosa and Sagitta serratodentata) found in a grid of 35 stations in the north Aegean Sea (Strymonikos and Ierissos Gulfs) was investigated through gut content analysis during five sampling periods from June 1997 to May 1998. Sagitta enflata and S. minima were the most abundant species in summer–autumn 1997 and in spring 1998, respectively. Copepods were the main food for all chaetognath species in spring 1998, while cladocerans in summer–autumn 1997 dominated the diet, especially of S. enflata. In September 1997, the juvenile specimens of cladocerans were the most important prey of the immature Stage I specimens of S. enflata, which resulted from the major breeding period in late summer. The estimated impact of chaetognath predation on the copepod and cladoceran communities ranged between 0.02–2.76% and 0.01–1.29% of the copepod and cladoceran standing stock, respectively. Stage I specimens of S. enflata accounted for nearly 90% of the total copepod and cladoceran standing stock consumed per day by the total population of this species in September 1997.
Northernmost record of Kyphosus sectator (Osteichthyes: Perciformes: Kyphosidae) in the north-eastern Atlantic
Authors: Canas Ana , Vasconcelos Paulo , Lino Pedro G. , Santos Miguel N.
Published: November 2005

This note reports the main morphometric and meristic parameters of a male Bermuda sea chub (Khyphosus sectator) caught off the Algarve coast (southern Portugal). This is the first occurrence of this tropical fish species in Portuguese continental waters, and the second and northernmost capture ever reported for the north-eastern Atlantic.
Bottlenose dolphins around Aberdeen harbour, north-east Scotland: a short study of habitat utilization and the potential effects of boat traffic
Authors: Sini M.I. , Canning S.J. , Stockin K.A. , Pierce G.J.
Published: November 2005

The aim of this study was to investigate the factors that affect the patterns of occurrence and habitat utilization of bottlenose dolphins around Aberdeen harbour, on the north-east coast of Scotland (UK), and their responses to boat traffic. Land-based surveys were conducted over a period of nine weeks, between early May and late July, 2002. During this time 83 sightings of bottlenose dolphins were recorded. Dolphins occurred more frequently around midday and early afternoon, while their abundance was greater around high tide and late afternoon. Foraging was the most commonly observed activity.

Dolphins were usually concentrated around the entrance of Aberdeen harbour. Their responses to boats varied considerably according to boat size, activity and speed, but there is evidence of habituation to boat traffic.
Ivermectin imposes selection pressure on P-glycoprotein from Onchocerca volvulus: linkage disequilibrium and genotype diversity
Authors: ARDELLI B. F. , GUERRIERO S. B. , PRICHARD R. K.
Published: November 2005

Widespread use of ivermectin (IVM) as part of the Onchocerciasis Control Program (OCP) in West Africa could influence the evolution of the human filarial parasite Onchocerca volvulus. Use of IVM, in some areas for 15 years, may have restricted genetic diversity of O. volvulus, resembling effects attributed to a population bottleneck. Large population-based chemotherapy programmes, such as the OCP, may impose strong selection pressure on parasites and an examination of possible genetic selection by IVM in O. volvulus is warranted. IVM is a substrate for P-glycoprotein; a homologue from O. volvulus (OvPGP) has been linked with IVM sensitivity. Linkage disequilibrium (LD) patterns of 28 genetic markers spanning the OvPGP locus were examined in 4 O. volvulus populations from the Volta Region of Ghana, West Africa. Reduced gene diversity, increased heterozygosity and an increase in the number of markers not in Hardy-Weinberg equilibrium were associated with increasing IVM treatment. The number of regions in LD decreased with treatment and with time. However, between 1999 and 2002, seven regions of OvPGP were always in complete LD, while surrounding areas showed a reduction in genetic variation. The use of IVM for onchocerciasis control has imposed strong selection on O. volvulus populations, reducing genetic variation and disrupting LD.
Vascular subcortical syndrome of aging
Authors: Fish Mark , Bayer Antony
Published: November 2005

Important and common syndromes of old age, such as dementia, parkinsonism, falls, depression, and urinary incontinence, may be associated with vascular pathology affecting subcortical brain structures. The advent of neuroimaging has brought this more to the attention of clinicians and researchers, with increasing evidence that the common findings of white matter change, and small lacunar infarcts are not entirely benign, as previously assumed. Such lesions are common in elderly populations: only 5% of 1077 subjects aged between 60 and 90 from the Rotterdam study were found to be completely free of white matter lesions. Even in otherwise healthy elderly people, such lesions may impact on cognitive and physical abilities.
Isotopic evidence for processes of sulfur retention/release in 13 forested catchments spanning a strong pollution gradient (Czech Republic, central Europe)
Authors: Novák Martin , Kirchner James W. , Fottová Daniela , Prechová Eva , Jăcková Iva , Krám Pavel , Hruska Jakub
Published: November 2005

Sulfur isotope systematics were studied in 13 small catchments in the Czech Republic, similar in topography (V‐shaped valley) and vegetation (Norway spruce). The sites differed in elevation, rainfall, bedrock, soil type and S pollution. Across the sites, δ34S values decreased in the order: bulk deposition > runoff > spruce throughfall > C‐horizon soil > A/B‐horizon soil > O‐horizon soil > bedrock (means of 5.5, 4.8, 4.7, 4.6, 4.2, 3.1 and 1.5‰, respectively). Some of the sites had a net export of S, while others accumulated S. Sites exporting S were located in the polluted north where atmospheric S input started to decrease in 1987. Sites retaining S were located in the relatively unpolluted south. Sulfur isotope composition of runoff depended on whether the catchment accumulated or released S. Sites releasing S had runoff δ34S values lower than deposition. In contrast, sites retaining S had runoff δ34S values higher than deposition. Across the sites, the δ34S values of runoff were not correlated with δ34S values of bedrock, indicating that the contribution of bedrock to S in runoff was negligible. The δ34S values of runoff were strongly positively correlated with the δ34S values of soil. Sulfur present in the C‐horizon of soils was mainly derived from atmospheric deposition, not bedrock. Sulfur isotope mass balances were constructed for each catchment, making it possible to quantify the difference between δ34S values of the within‐catchment source/sink of S and runoff S. Sulfur isotope mass balances indicated that the sink for the retained S at unpolluted sites and the source of the released S at polluted sites were isotopically fractionated by the same amount relative to runoff S. Inorganic and organic processes were considered as possible causes for this observation. Biological S cycling involves a variety of reactions, some of which fractionate S isotopes. In contrast, adsorption/desorption of inorganic sulfate in soil and weathering of S‐containing minerals do not fractionate S isotopes. Therefore the within‐catchment source/sink of S must be largely a result of biological S cycling. Organic S cycling played an important role over a wide range of atmospheric S inputs from 13 to 130 kg S ha−1 yr−1.
On the thermal impact of gas venting and hydrate crystallization
Authors: Chen Duo Fu , Cathles Lawrence M.
Published: November 2005

At the gas venting rates observed in some seafloor localities, heat advection and the latent heat of hydrate crystallization could significantly warm the subsurface, reduce the hydrate stability zone thickness, and decompose previously crystallized hydrate. Effects of heat advection and the latent heat of hydrate crystallization are limited by the duration of time over which venting occurs and ultimately by the time it takes to plug vents with hydrate, however. We examine the connection between gas venting, hydrate crystallization, and subsurface temperature using a new one‐dimensional analytical solution to the steady state heat flow equation with constant hydrate crystallization, and we examine the effects of the duration of venting employing one‐dimensional finite element solutions to the transient heat flow equation that include space‐ and time‐dependent hydrate dissolution and crystallization. We show that if lateral losses of heat are negligible, hydrate crystallization and the advection of heat by gas flow at the more vigorous rates of gas discharge observed on the seafloor could increase the temperature gradient near the surface by more than an order of magnitude and decrease the feed gas hydrate stability zone thickness from ∼570 to <200 m before the vents plug with hydrate. We compute how the chemistry of the venting gas and crystallizing hydrate evolve as a vent plugs with hydrate.
Active low‐angle normal faulting in the Woodlark extensional province, Papua New Guinea: A physical model
Authors: Westaway Rob
Published: November 2005

In eastern Papua New Guinea, the seismicity, geomorphology, and results of seismic reflection profiling, drilling, and structural geological analysis reveal a zone of active low‐angle normal faulting: the only clear known active example of this process worldwide. This Woodlark extensional province is ∼250 km long in the east‐west direction, located within the continental crust to the south of the Solomon Sea ocean basin. It adjoins the young oceanic spreading center farther east in the Woodlark Basin and since ∼4 Ma has accommodated northward extension at rates of in excess of 10 mm yr−1on low‐angle normal faults that are rooted to the north. This geometry and the region's earlier history are assessed in the light of modern ideas for the mechanics of low‐angle normal faulting to derive a working hypothesis for the existence of this process in this region. The extension in the Woodlark extensional province and oceanic spreading in the Woodlark Basin are thus interpreted as consequences of the slab pull force due to northward subduction of the Solomon Sea floor, which has caused the small Solomon Sea plate to separate from the Australian plate. It is suggested that this plate geometry developed by ∼6–5 Ma following the ending of southward subduction of the Solomon Sea floor beneath what is now the Woodlark extensional province. The double thickness of lithosphere that formerly existed locally cooled the continental crust, making it brittle to the Moho. Following the end of this subduction, the base of the continental lithosphere became progressively exposed to the asthenosphere, causing dramatic heating of the overlying continental crust. This resulted in transient thermal disequilibrium, inducing transient horizontal lower crustal flow. The shear tractions imparted on the base of the brittle layer by such flow (combined with the stress components that develop after some of the lower crust has flowed from beneath a locality, requiring it to be supported laterally rather than from below) will rotate the principal axes of the stress tensor sufficiently to enable low‐angle normal faults to form, and it is estimated that this sense of deformation was initiated around 4 Ma. The geometry of this study region means that this process will create north dipping low‐angle normal faults, as are observed. This scheme can also account for a great deal of other observational evidence, including the available thermochronologic evidence and the observed vertical crustal motions. To explain this instance of active low‐angle normal faulting thus requires knowledge of its relationship to earlier subduction and of effects of temperature‐dependent changes to continental crustal rheology in crust that was initially cold.
Geoscience Laser Altimeter System (GLAS) on the ICESat Mission: On‐orbit measurement performance
Authors: Abshire James B. , Sun Xiaoli , Riris Haris , Sirota J. Marcos , McGarry Jan F. , Palm Steve , Yi Donghui , Liiva Peter
Published: November 2005

The GLAS instrument on NASA's ICESat satellite has made over 904 million measurements of the Earth surface and atmosphere through June 2005. During its first seven operational campaigns it has vertically sampled the Earth's global surface and atmosphere on more than 3600 orbits with vertical resolutions approaching 3 cm. This paper summarizes the on‐orbit measurement performance of GLAS to date.
Remarks on the repulsive Wigner-Poisson system
Authors: Chae Myeongju , Ha Seung-Yeal , Huh Hyungjin
Published: November 2005

We present an estimate for the space-time integral of classical solutions to the repulsive Wigner-Poisson system. We use Markowich’s formalism between Wigner-Possion and Schrödinger-Poisson systems. Through this formalism and Morawetz interaction potentials, we derive the same a priori estimate given by Chae and Ha for the repulsive Vlasov-Poisson system.
Phase-field modeling of wetting on structured surfaces
Authors: Luo Kaifu , Kuittu Mikko-Pekka , Tong Chaohui , Majaniemi Sami , Ala-Nissila Tapio
Published: November 2005

We study the dynamics and equilibrium profile shapes of contact lines for wetting in the case of a spatially inhomogeneous solid wall with stripe defects. Using a phase-field model with conserved dynamics, we first numerically determine the contact line behavior in the case of a stripe defect of varying widths. For narrow defects, we find that the maximum distortion of the contact line and the healing length is related to the defect width, while for wide defects, it saturates to constant values. This behavior is in quantitative agreement with the experimental data. In addition, we examine the shape of the contact line between two stripe defects as a function of their separation. Using the phase-field model, we also analytically estimate the contact line configuration and find good qualitative agreement with the numerical results.
A classification of generalized quantum statistics associated with basic classical Lie superalgebras
Authors: Stoilova N. I. , Van der Jeugt J.
Published: November 2005

Generalized quantum statistics such as para-statistics is usually characterized by certain triple relations. In the case of para-Fermi statistics these relations can be associated with the orthogonal Lie algebra Bn=so(2n+1); in the case of para-Bose statistics they are associated with the Lie superalgebra B(0∣n)=osp(1∣2n). In a previous paper, a mathematical definition of “a generalized quantum statistics associated with a classical Lie algebra G” was given, and a complete classification was obtained. Here, we consider the definition of “a generalized quantum statistics associated with a basic classical Lie superalgebra G.” Just as in the Lie algebra case, this definition is closely related to a certain Z-grading of G. We give in this paper a complete classification of all generalized quantum statistics associated with the basic classical Lie superalgebras A(m∣n),B(m∣n),C(n), and D(m∣n).
The effect of low-temperature strain on the structure and the critical-current degradation of the superconducting alloy Nb–Ti
Authors: Volchok O. I. , Lazareva M. B. , Mats A. V. , Starodubov Ya. D. , Chernyak N. A. , Chernyĭ O. V.
Published: November 2005

The structural-phase aspects of the behavior of the critical current under load in the superconductive alloy Nb–48.5 wt% Ti are studied. It is shown that the optimum preliminary strain at T=77 K with subsequent annealing suppresses the tendency of the β matrix of the alloy to undergo phase transformations according to martensitic kinetics under uniaxial tension at T=4.2 K, and this is manifested in the reduction of the critical-current degradation effect when loaded to σ=0.9σfr in a transverse magnetic field of H=5 T. The paper discusses possible critical-current degradation mechanisms under mechanical loading in the niobium-titanium alloy, based on models of critical current flow in the β matrix reinforced with martensitic interlayers.
A low-temperature plasticity anomaly of concentrated fcc solid solutions: the Pb–In system
Authors: Isaev N. V. , Natsik V. D. , Pustovalov V. V. , Fomenko V. S. , Shumilin S. É.
Published: November 2005

This paper discusses the regularities of the plastic strain of single crystals of solid solutions of the Pb–In system at low and very low temperatures, 0.5 K<T<30 K. For Pb alloys with 5, 10, and 20 at. % In, the temperature dependences of the yield strength, τ0(T), and of the increment of the deforming stress, Δτ(T), are measured after a tenfold increase of the strain rate. Specific features (anomalies) of these dependences are detected that do not correspond to concepts of thermally activated motion of dislocations through impurity barriers. It is established that the character of the anomalies substantially changes as the indium concentration varies from moderate values (5 and 10 at. %) to high values (20 at. %). The low-temperature plasticity anomaly of moderately concentrated alloys is interpreted on the basis of the concepts of thermal-inertial and quantum-inertial motion of dislocations through a system of single impurity atoms. In the case of the highly concentrated alloy, the anomaly is interpreted in terms of a model of an inhomogeneous impurity distribution—the presence in the alloy of small clusters that create stronger barriers for the motion of dislocations than do single impurity atoms. The high level of efficient deforming stresses under conditions of deep cooling results in a dynamic regime of dislocation motion through the system of clusters and single impurities, with the yield strength τ0 of the alloy being determined by impurity inhibition of dry-friction type, while the rate sensitivity Δτ of the deforming stress is determined by viscous inhibition by electrons and phonons. The athermal character of impurity dry friction and the sharp decrease of viscous friction upon cooling determine the character of the anomaly in this case.
Electron paramagnetic resonance study of the singlet magnet KTb(WO4)2
Authors: Dergachev K. G. , Kobets M. I. , Loginov A. A. , Khatsko E. N.
Published: November 2005

The electron paramagnetic resonance (EPR) spectrum of KTb(WO4)2 is investigated in the frequency range 14–120 GHz and magnetic field range 0–70 kOe at helium temperature. The observed triplet structure of the spectrum is interpreted as a manifestation of resonance in three-site clusters. On this basis a value of the g factor (g≈13.3) and an estimate of the gap (δ≈1 K) are obtained for the quasi-doublet ion Tb3+ in the crystalline field of KTb(WO4)2, and the parameters of the dipole (Id≈1.6 K) and exchange (Iex≈0.9 K) AFM interactions of the nearest neighbors in the chains are determined for the corresponding singlet magnet model. A first-order structural phase transition, induced by an external magnetic field lying in the basal plane of the crystal, is observed.
On the alignment dynamics of a passive scalar gradient in a two-dimensional flow
Authors: Garcia A. , Gonzalez M. , Paranthoën P.
Published: November 2005

A Lagrangian study of the statistical properties of the orientation of a passive scalar gradient is performed using experimental data and a simple, numerical analysis. It is shown that, in a low-Reynolds number Bénard-von Kármán street, the temperature gradient downstream of a heated line source does not align with the asymptotic orientation predicted by the Lapeyre et al. model [Phys. Fluids 11, 3729 (1999)] in the hyperbolic regions. This result is ascribed to fluctuations of strain persistence along Lagrangian trajectories. A numerical analysis of the scalar gradient alignment properties shows that these fluctuations, together with a low level of the rate of strain, may lead to preferential orientations that are different from the theoretical one predicted by an asymptotic model.
Vertically aligned, catalyst-free InP nanowires grown by metalorganic chemical vapor deposition
Authors: Novotny Clint J. , Yu Paul K. L.
Published: November 2005

Vertically-aligned InP nanowires are grown by metalorganic chemical vapor deposition (MOCVD) without the use of a deposited metal catalyst. A surface reconstruction induces indium droplets to form on the surface and thus act as nucleation sites for nanowire growth. Vertical growth from the InP(111)B substrate along with transmission electron microscopy (TEM) analysis indicate epitaxial growth from the substrate in the [111]B direction. A uniform cross section along the longitudinal axis can be achieved by optimizing the input V∕III ratio. Small variations in the diameter and length are seen under optimal growth conditions.
Fabrication of high performance light rare earth based single-grain superconductors in air
Authors: Babu N. Hari , Iida K. , Shi Y. , Cardwell D. A.
Published: November 2005

Large, single-grains of (LRE)-Ba–Cu–O (LRE=light rare earth: Nd, Sm, and Gd) bulk high-temperature superconductors with significantly improved properties have been fabricated in an air atmosphere using a practical processing technique based on seeded infiltration growth. This process involves the use of a generic seed crystal, developed recently at the IRC in Superconductivity, to promote epitaxial grain nucleation. The formation of a solid-solution phase within the nucleated single grain is then suppressed effectively by providing excess Ba to the growth front under an air processing atmosphere. Critical current densities in excess of 105A∕cm2 at 77K have been observed in the resulting large grain samples, with an associated and significant improvement in trapped magnetic field. This air-based seeded-infiltration-growth process offers a significant degree of freedom both in terms of the processing parameters and the reproducibility in growth of oriented single grains.