bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic Transport Properties of Hot-Pressed B6Si
Authors: Wood C. , Emin D. , Feigelson R. S. , Mackinnon I. D. R.
Published: March 2011

Measurements of the electrical conductivity, Seebeck coefficient and Hall mobility from -300 K to -1300 K have been carried out on multiphase hotpressed samples of the nominal composition B6Si. In all samples the conductivity and the p-type Seebeck coefficient both increase smoothly with increasing temperature. By themselves, these facts suggest small-polaronic hopping between inequivalent sites. The measured Hall mobilities are always low, but vary in sign. A possible explanation is offered for this anomalous behavior.
Thermoelectric Properties of SmSl−xAsx Alloys
Authors: Danielson L. R. , Alexander M. N. , Lockwood R. A. , Wood C.
Published: March 2011

The electrical resistivities and the Seebeck coefficients of SmS1−xAsx alloys (0 ≤ x ≤ 1) have been measured between room temperature and 1273 K as part of a continuing search for high temperature materials having a high thermoelectric figure of merit and suitable for space power applications. SmS is an n-type semiconductor with an energy gap measured to be 0.16 eV. SmAs and SmS0.2As0.8 are itinerant electron conductors. Hysteresis between high and low resistivity states has been observed in our SmS0.9As0.1 and SmS0.8As0.2 samples. Alloys with x ≤ 0.05 appear to be the most promising high temperature thermoelectric materials.
Properties of Gallium Nitride
Authors: Pankove Jacques I.
Published: March 2011

Gallium nitride has many useful properties that include a large direct gap, high electrical and thermal conductivities, and nearly the hardness of sapphire. GaN decomposes at -100°C, can sustain high electron velocities and exhibit acoustoelectric effects. But two challenges remain: to make it conducting p-type and to synthesize the cubic phase in a large single crystal instead of the usual hexagonal structure.
Origin of Paramagnetic Defect in Single Crystal and Ceramic B4C
Authors: Venturini E. L. , Emin D. , Aselage T. L.
Published: March 2011

We compare electron spin resonance (ESR) spectra of B4C samples made by three methods. The samples are 1) two ceramics made by hot-pressing boron and carbon powders, 2) a polycrystal made by carbothermic reduction, and 3) a single crystal grown from a palladium metal melt. All samples show remarkably similar spectra between 2 and 100 K. In particular, all samples show a single Lorentzian absorption, a linewidth that decreases with increasing temperature, and an inverse temperature dependence of the integrated intensity. The integrated intensity of the paramagnetic spin signal corresponds to a density of 2×1019/cm2 localized spins. Having a single crystal sample enables us to meaningfully measure the angular dependence of the ESR linewidth. This angular dependence is consistent with the paramagetic centers being unpaired electrons centered on the central carbon atoms of positively charged C-C-C intericosahedral chains. These chains appear to replace 0.5 % of the positively charged C-B-C intericosahedral chains which occur in B4C.
A Theoretical Approach to the Thermal Conductivity of Boron Carbides
Authors: Kenkre V. M. , Fan X.
Published: March 2011

The thermal conductivity of boron carbides at high temperatures presents a fundamental challenge to theory. One of the striking features is that, while in B4C it displays “normal” behaviour in that it decreases with increasing temperature, in B9C it is nearly temperature-independent. We address this feature through a model calculation which assumes the heat current to be due to carrier phonons whose frequency is modulated by lower-frequency phonons which “dress” the carrier phonons through strong interaction. Preliminary calculations show satisfactory but partial agreement with experiment for reasonable parameters and delineate areas for further investigation of the vibrational properties of boron carbides.
A Spectroscopic Study of the Conditions Required for Plasma Etching of Aluminium in BCl3 and Cl2 Plasmas
Authors: Cairns J. A. , Smailes R. , Blaikley D. C. W. , Banks P. M. , Hancock G. , Hussla I. , Katzschner W.
Published: March 2011

Optical Emission Spectroscopy (OES) with argon actinometry has been used to study the influence of machine parameters on the composition of a BCl3 RF plasma discharge in the absence and presence of aluminium. Two steady state models are proposed to account for the appearance of the various species seen, and to explain their relative abundances in response to changes in power and pressure. The validity of the actinometric technique for measuring relative changes in ground state concentrations is discussed also.
The Potential of Infrared Video Thermography for Control of Arc-Plasma Spray Fabrications
Authors: Harris D. , Kelly M.
Published: March 2011

Infrared video thermography was used to evaluate the plasma plume and particle streams created by dc plasma jets operating in air and spraying several types of materials. The temperatures of the plasma plume were measured with the aid of a graphite ‘witness.’ By using the thermography system in an 8khz line scan mode, we were able to obtain data relative to the average velocity of particle groups injected into the plasma. The effects of process parameters could be observed in real time using these methods, showing the potential for real time process control.
Diagnostic Techniques for Thermal Plasmas
Authors: Self Sidney A.
Published: March 2011

A broad overview is given of diagnostic techniques applicable to thermal plasmas used for materials processing, chemical synthesis and plasma spraying.
Pulsed Inductive Plasma Processing for Amorphous Thin Film Formation
Authors: Ebihara Kenji , Maeda Sadao
Published: March 2011

A pulsed electromagnetic inductive discharge is used to prepare amorphous thin films. The pulsed plasma is generated by supplying pulsed current (maximum peak 70 kA, period 13 μs ) to a one-turn coil wound round a Pyrex glass tube. Amorphous silicon(a-Si) and amorphous carbon (a-C) films were deposited in mixture gas (20% SiH4, 80% Ar) and pure methane, respectively. The films formed on the subltrates set normal to the tube axis at a pressure of 10–200mTorr and a gas flow rate of 10–20 sccm. Deposition rate was about 1 nm per a single discharge shot. The deposited films of a few hundred nanometer thickness adhered well to room-temperature substrates. The a-Si films had optical gap of ˜ 1.7 eV. The a-C films were transparent in the IR range and had optical gap of 1.0 ˜ 2.0 eV. Relative spectral intensity measurement of the Balmer emission from hydrogen atoms showed that the electron temperature at the high electromagnetic compression phase is 1˜ 2 eV in silane discharges and 2˜5 eV in methane discharges.
Photoresist Stripping Using a Remote Plasma: Chemical and Transport Effects
Authors: Loewenstein Lee M. , Huffman Craig H. , Davis Cecil J.
Published: March 2011

Photoresist removal from silicon substrates has been achieved by a dry processing method using a plasma remote from the substrate to produce active species. Although the principal gas used is oxygen, the addition of small amounts of other gases (N2O, HCI, HBr, H2, Cl2, CF4, and CHF3) has been shown to significantly enhance resist removal. The measured temperature dependences indicate that the effect of these additives may be a combination of oxygen atom production enhancement by neutral and ionic mechanisms as well as independent reaction with the resist.
A Kinetic Model for Low-Pressure RF Discharge Etching of Silicon Using SF6
Authors: Paranjpe Arit P. , Kychakoff George , Self Sidney A.
Published: March 2011

The variation of etch rate with power, pressure and flow is studied using a coupled electron and chemical kinetics model. The electron kinetics model involves a solution of the electron continuity and current continuity equations in conjunction with the Boltzmann equation. The temporal variation of the electric field, electron energy distribution function (EEDF) and electron number density in the bulk of an RF discharge, is calculated using measured current waveforms, and calculated species concentrations. Electron generation through electron-impact ionization, is balanced by attachment and diffusion losses. A time-dependent solution of the Boltzmann equation is employed to investigate the problem of non-equilibrium, between the EEDF and the instantaneous field. Rates for electron impact processes are calculated using the EEDF.

Rate equations for the different species are solved to obtain steady state species concentrations. Radicals and ions produced by electron-impact processes are lost through neutral recombination, ion-ion neutralization, diffusion to reactor surfaces and flow losses. The calculated ion number densities far exceed the electron number density. A transport model that considers the diffusion of etchant species to the wafer and subsequent reaction, is used to compute the etch rate.
Gate Oxide Damage in Dry Photoresist Stripping Environments
Authors: Sibbett Karen H. , Ulacia J. Ignacio , McVittie James P. , Reichelderfer Richard F.
Published: March 2011

The effect of oxygen plasma stripping environments on the electrical properties of thin oxides has been studied. A barrel, parallel plate and downstream stripper are compared. Damage, measured by shifts in flatband voltage (Δ Vfb), increases in the density of interface traps (Dit), and degradation in minority carrier lifetimes, was observed in all plasma processed samples. Plasma treated wafers had 10–100 fold increases in Dit but recovered to nearly control levels after a 450 °C anneal. ΔVfb and lifetimes did not recover in all cases. Mobile ion contamination dominated in the high temperature (≥ 250 °C) downstream stripping tool. The mobile ion concentration was halved by decreasing the process temperature in the downstream etcher. Ion bombardment-induced damage appears to be most important in the parallel plate configuration. Lifetime results were poor for wafers etched in an unshielded barrel reactor and did not recover after anneal. Use of an etch tunnel improved results to control levels. Degradation of minority carrier lifetimes measured using the photoconductivity technique correlated well with changes in Vfb and Dit. This measurement provides a simple method for evaluating plasma-induced damage.
Plasma Process Routes to Synthesis of Carbide, Boride and Nitride Ceramic Powders
Authors: Becker Aaron J. , Meyer Thomas N. , Smith Frances N. , Edd Jon F.
Published: March 2011

An iterative technique to develop plasma processing, consisting of identifying materials with unique properties, calculating conversion efficiencies, product purity and power from thermodynamic data for the chemical reactions selected to produce it and modeling the process mathematically and physically to determine capital and labor costs is illustrated with production of silicon carbide and titanium diboride in Alcoa's DC plasma facility. The work shows that submicron silicon carbide and titanium diboride containing less than 0.2% oxygen can be produced with plasmas at costs competitive with traditional processes. It has also been reported that aluminum nitride, a material which has the high thermal conductivity needed for high power electronic substrates, can be satisfactorily produced by reacting aluminum powder with nitrogen in an RF plasma system. Future application of plasmas for production of ceramics will depend on discovery of unique properties and cost effective process optimization.
Stability Studies of Plasma Sprayed Zirconia
Authors: Eaton Harry E. , Novak Richard C.
Published: March 2011

Sprayed partially stabilized zirconia (PSZ) has a non equilibrium microstructure due to the splat quench nature of the spray process and it will undergo phase transformation with time at temperature. This study examines the phases present in sprayed PSZ versus powder history, exposure to temperature, and silica impurity level. Finally, thermal quench behavior is examined versus phase content.
Beta-SiC Synthesis in a Thermal Argon Plasma Jet Reactor
Authors: Kong Peter C. , Pfender E.
Published: March 2011

Ultrafine beta-SiC powders are synthesized in a thermal argon plasma jet reactor by a reaction between methane and silicon monoxide. High temperatures (>10000 K) and rapid quench rates (>106 K/s) lead to a high degree of super-saturation of the chemical vapor, resulting in homogeneous nucleation of ultrafine SiC particles. The maximum conversion of SiO to SiC determined by thermogravimetric analysis is 97%. Particle size analyses show a bimodal distribution with the majority of the particles falling in a size range from 2 to 40 nm. Larger particles with sizes larger than 80 nm are also observed. Characteristically-shaped SiC single-crystal platelets are observed throughout this work.
A Mathematical Representation of the ion Nitriding Process
Authors: Marchand J -L. , Ablitzer D. , Szekely J. , Michel H. , Gantois M.
Published: March 2011

A mathematical formulation and computed results are presented to describe the velocity fields, temperature fields and concentration of the activated species in an ion nitriding process, operated at 1–5 torr pres-sure. The theoretical predictions, which are based on the two-dimensional trasnport equations and on a model for computing the electron number density, gave results in broad agreement with experimental findings reported by others for similar systems.
Effect of Particle Loading on DC Plasma Jet Profile During Low Pressure Plasma Deposition
Authors: Wei Daniel Y.C. , Apelian Diran , Farouk Bakhtier
Published: March 2011

In modelization of plasma jet profiles and calculating individual particle trajectories and the local temperature profile of the injected particles it has generally been assumed that the particles injected into the plasma plume constitute a dilute system. The latter allows one to decouple the jet profile calculations from the particle trajectory and temperature calculations. However, in practice, low pressure plasma deposition is carried out under high loading conditions to minimize thermal energy losses. In addition, the plasma experiences local cooling and deceleration due to the high loading of the injected particles. The effect of powder injection rates (10 kg/hr -30 kg/hr) on the plasma and the particles was studied and numerically modeled. An axisymmertrical parabolic supersonic flow model with compressibility corrected k-… turbulence formulation was developed and used in this study to describe the jet flow. The exchange of energy and momentum between the injected particles and the plasma flow was treated by considering the source term of the governing equations. The effect of particle loading on the resulting jet profiles, particle trajectories and temperature profiles are presented and discussed.
Does Host Size and Feeding Status Influence the Egg Load of Microplitis rufiventris (Hymenoptera: Braconidae)?
Authors: Khafagi Wedad E , Hegazi Esmat M , Andersson Peter , Schlyter Fredrik
Published: March 2011

Laboratory experiments were conducted to determine the effect of host instar and feeding status on the egg load of early life stage in Microplitis rufiventris Kokujev (Hymenoptera: Braconidae), a solitary koinobiont endoparasitoid of some noctuid pests. The wasps that developed from fourth or fifth instars of Spodoptera littoralis (Boisduval) larvae were heavier in weight than those from earlier stages. Different numbers of mature eggs were found in the two ovaries of the female wasp. Egg loads, corresponding to fitness, were significantly influenced by female weight and feeding status. However, the interactions between the two treatment factors were not significant. The average number of mature eggs carried by females at eclosion time ranged from 52 eggs in smaller wasps to 62 eggs in larger wasps. Females that were fed had higher egg loads and egg maturation rate than unfed females. However, female wasps were capable of maturing considerable number of eggs without feeding; suggesting that they produce a certain portion of eggs from nutritional reserves that had been stored during larval stage. Female wasps are weakly synovigenic, with an egg maturation at a rate of ≈1.8 eggs per h. Further investigation is required to verify the rate of egg maturation and eventually egg resorption in different stages of adult female M. rufiventris.
Analysis of Surstylus and Aculeus Shape and Size using Geometric Morphometrics to DiscriminateRhagoletis pomonellaandRhagoletis zephyria(Diptera: Tephritidae)
Authors: Yee Wee L , Sheets H David , Chapman Peter S
Published: March 2011

Rhagoletis pomonella (Walsh) and Rhagoletis zephyria Snow (Diptera: Tephritidae) both occur in the U.S. Pacific Northwest and are frequently confused with one another due to their morphological similarity. The apple maggot, R. pomonella, is a threat to commercial apples [Malus domestica (Borkh.) Borkh.] in the Pacific Northwest, whereas R. zephyria attacks snowberry (Symphoricarpos Dill. ex Juss) and is not considered a threat. Configuration of the surstyli in males is used to discriminate between species, but this character shows overlap. In this study, we reexamined surstyli configurations in the two species. We then used geometric morphometrics to test the hypotheses that shapes of surstyli and of aculei between the two species differ and that combining aculeus shape and size measures improves discrimination. We found that all R. pomonella had an inwardly curved surstyli configuration (based on a ratio of width across bases of prensisetae to width between the outer edges of the surstyli near their ends), whereas R. zephyria included specimens having either a parallel or divergent configuration. Using canonical variates analysis, multivariate analysis of variance, and an assignments test, we found that surstylus shape classified 99.8% of males correctly to species. Aculeus shape accurately classified 85.3% of females to species. Combining aculeus shape and length increased classification accuracy to 94.5%. Within species, surstylus and aculeus shape did not discriminate among fly populations from different host fruit, collection areas, or both. Use of surstylus shape would benefit regulatory agencies that depend on accurate identifications of R. pomonella for quarantine and management measures.
Impact of the Red Imported Fire Ant (Hymenoptera: Formicidae) on Epigeic Arthropods of Cotton Agroecosystems
Authors: Wickings Kyle G , Ruberson John
Published: March 2011

The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), has been studied extensively in its role in aboveground food webs of agroecosystems of the southern United States. There is also a limited body of evidence suggesting that S. invicta may significantly influence the soil fauna. This study examined the influence of fire ants on the arthropod communities at the soil surface of cotton, Gossypium hirsutum L., fields at two field sites operated by the University of Georgia in Athens and Tifton, GA (1 yr at each location). Fire ant abundance was suppressed in large plots with ant-specific hydramethylnon-based bait, and arthropods were collected from treatment and control plots by using pitfall traps during multiple week-long sample periods to measure the abundance of epigeic arthropods. Sampling was conducted from June through September 2006 in Athens and from July through September 2007 in Tifton. Although fire ant suppression decreased the abundance of erythraeid mites and nitidulid beetles at both sites, the majority of effects were site-specific. Other taxa positively associated with fire ants included oribatid mites and gnaphosid and linyphiid spiders. In contrast, the abundance of springtails, earwigs, endomychid beetles, and thrips increased with fire ant suppression. This study demonstrates that S. invicta can significantly influence both pest and beneficial epigeic arthropods and that although fire ants exert clear effects on specific taxa, their effects are not uniform within a given trophic group as members from the same guild were differentially impacted.
Seasonal Occurrence and Development of Degree-Day Models for Predicting Activity ofConotrachelus nenuphar(Coleoptera: Curculionidae) in Alabama Peaches
Authors: Akotsen-Mensah Clement , Boozer Robert T , Appel Arthur G , Fadamiro Henry Y
Published: March 2011

The plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), is a key pest of peaches, Prunus persica (L.) Batsch, in North America. Captures of adult weevils in unbaited pyramid traps recorded annually from 2000 to 2008 in an unmanaged peach orchard in central Alabama were used to determine its seasonal occurrence and to develop predictive degree-day models. Spring migration of plum curculio began at bloom (early to mid-March). Linear, polynomial, and three-parameter Weibull functions were tested to describe the relationship between weekly trap capture and cumulative degree-day (DD). Criteria used to select the best models were the smallest Akaike information criterion and highest R2 values. A sixth-order polynomial function fitted best to seasonal trap captures and cumulative DDs and revealed two major seasonal peaks with the first (spring generation) and second (summer generation) peaks occurring at cumulative DDs of ≈245 and 1105 (base 10°C, biofix of 1 January), respectively. A potential third (late summer generation) peak was observed at 1758 DDs. The sixth-order polynomial model predicted the first trap capture to occur at cumulative DD of ≈99 (base 10°C, biofix of 1 January). The three-parameter Weibull model predicted the first trap and first peak (spring generation) trap captures to occur at mean cumulative DDs of 108.02 ± 9 and 220.07 ± 16, respectively. Validation of the models in the unmanaged orchard in 2009 and 2010 and in a second unmanaged orchard (located 1.6 km from the first) in 2009 showed that the polynomial and Weibull were within ±7 d in their predictions of the first and peak trap captures of the spring population. Validation results showed that both models successfully predicted the first trap capture in one out of three scenarios and the peak trap capture in two out of three scenarios. The performance of the models is discussed in relation to management of plum curculio in central Alabama.
Diversity of Neotropical Harvestmen (Arachnida: Opiliones) Inhabiting Logs and Palm Fronds in the Rain Forests of Trinidad
Authors: Proud Daniel N , Tibbetts Jessica A , Moore Michael K , Townsend Victor R
Published: March 2011

In July and August 2005, we investigated the use of two distinct microhabitats by harvestmen (Arachnida: Opiliones) in crappo-cocorite seasonal forest, lower montane rain forest, and upper montane rain forest of the Northern Range of Trinidad, West Indies. In addition to new locality records, geographic distributions, and microhabitat use, this article provides a preliminary understanding of the species diversity, compositional similarity, and relative harvestmen abundance among forest stands located within three types of rain forest of different altitudes found in Trinidad. We collected harvestmen inhabiting the space within and underneath decaying logs as well as the leaf litter associated with the logs. In upper montane rain forest, in addition to logs, we sampled the sheaths of palm (Euterpe broadwayi Becc. ex Broadway) fronds, another shelter commonly used by harvestmen that was especially abundant at the higher elevations. We collected 173 individuals representing eight families and 14 species. The number of harvestmen per shelter varied from 3.2 individuals per log in crappo-cocorite forest to 0.8 individual per log or palm frond sheath in upper montane rain forest. In the crappo-cocorite seasonal forest, cosmetids, sclerosomatids and stygnids were most abundant. In upper montane rain forest, cranaids and manaosbiids were the most abundant taxa, whereas cosmetids and sclerosomatids were relatively rare. Crappo-cocorite and lower montane forests were very similar in species composition but differed greatly from upper montane forest. The cosmetids Paecilaema ingleiGoodnight and Goodnight 1947, Cynortula granulata Roewer 1912, and the stygnid Stygnoplus clavotibialis (Goodnight and Goodnight 1947) were found to be strongly correlated with the crappo-cocorite and lower montane forests, whereas in upper montane forests Santinezia serratotibialisRoewer 1932 and Cranellus montgomeryiGoodnight and Goodnight 1947 were closely correlated.
Seed Preferences of Three Harvester Ants of the Genus Pogonomyrmex (Hymenoptera: Formicidae) in the Monte Desert: Are They Reflected in the Diet?
Authors: Pirk Gabriela Inés , Casenave Javier Lopez De
Published: March 2011

Harvester ants play an important ecological role as seed consumers in arid areas. We performed choice experiments to study preferences of Pogonomyrmex rastratus (Mayr), Pogonomyrmex mendozanus (Cuezzo & Claver), and Pogonomyrmex inermis (Forel) (Hymenoptera: Formicidae) for seeds of six native species (three grasses, two forbs, and a shrub) in the central Monte desert, Argentina. We hypothesized that ant diet composition would reflect ant preferences. Thus, based on previous ant diet studies, we expected that 1) the three species would prefer grass to nongrass seeds, 2) P. inermis would have a lower preference for nongrass seeds than P. rastratus and P. mendozanus and 3) relative abundance of seeds in the diet would be positively associated with relative preference. In general, relative abundance of seeds in the diet was positively associated with relative preferences. Ants preferred grass seeds, but P. inermis did not have a lower preference for nongrass seeds. We also analyzed the relationship between preferences for seeds of the six species and their size and morphology, and we found higher preferences for seeds of intermediate size but no relationship with seed morphology. The overall match between seed preferences and diet composition could increase the chances of ants affecting the abundance and composition of some seed resources in the Monte desert, with important community implications.
A New Species of Trechus from the Ethiopian Highlands (Coleoptera: Carabidae: Trechinae) and Key to the Trechus Species of Ethiopia
Authors: Ortuño Vicente M , Novoa Francisco
Published: March 2011

The enormous genus Trechus Clairville is distributed mainly in the Holarctic regions, but 24 species from Ethiopia were described previously. A key to the species of Ethiopian Trechus is provided, including a new species, Trechus amharicus from the Choke Mountains (Ethiopian Highlands). The latter taxon is described. The species was found in the Afroalpine grassland, living under stones, sometimes located at the base of the giant Lobelia rhynchopetalum Hemsl. It is noteworthy that in spite of the small number of known species of Ethiopian Trechus, there are more morphological and chaetotaxic variations among them than in their Holarctic congeners. The taxonomic position of the new species is difficult to situate, because T. amharicus does not fit in any of the groups of species recognized to date in Ethiopia. T. amharicus n. sp. bears some resemblance to T. patrizii in that it has a pronotum with posterior angles without setae, and elytra with only a single anterior discal seta. However, the different configuration of the protarsus and aedeagus in the male clearly separates the two taxa.
Glutathione Transferase and Cytochrome P450 (General Oxidase) Activity Levels in Candidatus Liberibacter Asiaticus-Infected and Uninfected Asian Citrus Psyllid (Hemiptera: Psyllidae)
Authors: Tiwari Siddharth , Pelz-Stelinski Kirsten , Mann Rajinder S , Stelinski Lukasz L
Published: March 2011

Candidatus Liberibacter asiaticus (Las) has been reported to increase the susceptibility of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), to selected insecticides. Reduced general esterase activity in Las-infected, compared with uninfected, D. citri has been proposed as a possible explanation for this difference in insecticide susceptibility. The current study was conducted to quantify glutathione transferase (GST) and cytochrome P450 (general oxidase) activities in Las-infected D. citri to further explain the possible mechanisms for altered susceptibility to insecticides due to Las infection. GST and cytochrome P450 activities (indirectly through general oxidase levels) were quantified in Las-infected and uninfected D. citri nymphs and adults. Mean (±SEM) GST activity was significantly lower in Las-infected (468.23 ± 26.87 /µmol/min/mg protein) than uninfected (757.63 ± 59.46 µmol/min/mg protein) D. citri adults. Likewise, mean cytochrome P450 activity was significantly lower in Las-infected (0.23 ± 0.02 equivalent units [EU] cytochrome P450/mg protein) than uninfected (0.49 ± 0.05 EU cytochrome P450/mg protein) D. citri adults. Immature stages (second and fifth instars) were characterized by significantly lower GST activity than adults for uninfected D. citri. However, cytochrome P450 activity was significantly higher in second instar nymphs than adults and fifth-instar nymphs for uninfected D. citri. Lower activities of GST and general oxidase in Las-infected D. citri indicate that infection with Las alters D. citri physiology in a manner that could increase insecticide susceptibility. The reduced activities of these detoxifying enzymes due to Las infection may be explained by examining expression levels of associated genes in Las-infected and uninfected D. citri.
Anatomy of Accessory Salivary Glands of the Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) and Correlations to Begomovirus Transmission
Authors: Cicero Joseph M , Brown Judith K
Published: March 2011

Visualization of dissected accessory salivary glands (ASGs) of the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) by light microscopy (LM) revealed three distinctive toluidine blue O stain profiles. Considered morphotypes, the three profiles are hypothesized to represent stages of a salivation cycle, wherein contents are cyclically depleted and subsequently regenerated as needed for feeding. When whiteflies were repeatedly interrupted during their initial feeding behaviors, and then ASGs were dissected, a fourth stain profile was revealed. These observations are therefore relevant to the different mechanisms involved in whitefly-mediated virus transmission to plants. Stain techniques involved in transmission electron microscopy of extirpated and nonextirpated ASGs reveal entirely different profiles that cannot yet be correlated to LM findings. The midgut of B. tabaci is capable of transposing its location from the abdomen to the thorax and can come into direct contact with the ASGs. This finding opens new lines of thought in the potential for interaction between the two, such as purging of excess water and waste, and virus transmission.
Sphenothallus-like fossils from the Martinsburg Formation (Upper Ordovician), Tennessee, USA
Authors: Wei-Haas Maya Li , Glumac Bosiljka , Curran H. Allen
Published: March 2011

Tubular fossils, up to 2 mm in diameter and 60 mm in length, occur rarely in the upper Martinsburg Formation (Upper Ordovician), northeastern Tennessee Appalachians, U.S.A. The fossils are unbranched, straight or slightly bent, occasionally twisted and wrinkled, and not significantly tapered. Orientation of the fossils within shallow-marine tempestites suggests that they represent remains of organisms that were broken, transported, and deposited by storm waves and currents. The fossils are morphologically similar to many of the previously identified species belonging to the genusSphenothallus, a relatively rare tube-dwelling Paleozoic marine invertebrate. Owing to the limited evidence for distal widening of the tubes, lack of holdfasts, and carbonaceous rather than phosphatic composition, the affinity of these fossils remains uncertain, and we refer to them asSphenothallus-like.
The structure of cranidial shape variation in three early ptychoparioid trilobite species from the Dyeran-Delamaran (traditional “Lower-Middle” Cambrian) boundary interval of Nevada, U.S.A.
Authors: Webster Mark
Published: March 2011

The structure of cranidial shape variation in the early ptychoparioid trilobitesCrassifimbra walcotti, Crassifimbra?metalaspis(new combination), andEokochaspis nodosais explored using landmark-based geometric morphometric techniques, and is found to be generally similar among the species. Allometry is the strongest single source of cranidial shape variation within each species. The species share several trends in their respective patterns of ontogenetic shape change, but differ in the relative magnitude of these shared trends. Species-specific trends are also present. Each species follows a unique trajectory of ontogenetic shape change. The species exhibit subtle but significant differences in mean cranidial shape even at small size (sagittal length 1.75 mm); the magnitude of interspecific differences becomes larger at larger size (sagittal length 4.2 mm).

For conspecific cranidia of a given size, the major pattern of covariance among anatomical parts is essentially identical to the pattern of covariance among those parts during ontogeny. Developmentally determined covariance patterns among cranidial regions might be responsible for ontogenetic shape change and a portion of non-allometric shape intraspecific variation. Interspecific differences in cranidial shape resulted from complex local modifications to growth pattern and cannot be attributed to simple ontogenetic scaling.

The new collections permit the first description of non-cranidial sclerites ofC. walcotti.A cephalic median organ is documented onC. walcotti, representing the oldest known occurrence of this structure in trilobites.
Remarks on Muscle Contraction Mechanism II. Isometric Tension Transient and Isotonic Velocity Transient
Authors: Mitsui Toshio , Takai Nobukatsu , Ohshima Hiroyuki
Published: March 2011

Mitsui and Ohshima (2008) criticized the power-stroke model for muscle contraction and proposed a new model. In the new model, about 41% of the myosin heads are bound to actin filaments, and each bound head forms a complex MA3 with three actin molecules A1, A2 and A3 forming the crossbridge. The complex translates along the actin filament cooperating with each other. The new model well explained the experimental data on the steady filament sliding. As an extension of the study, the isometric tension transient and isotonic velocity transient are investigated. Statistical ensemble of crossbridges is introduced, and variation of the binding probability of myosin head to A1 is considered. When the binding probability to A1 is zero, the Hill-type force-velocity relation is resulted in. When the binding probability to A1 becomes finite, the deviation from the Hill-type force-velocity relation takes place, as observed by Edman (1988). The characteristics of the isometric tension transient observed by Ford, Huxley and Simmons (1977) and of the isotonic velocity transient observed by Civan and Podolsky (1966) are theoretically reproduced. Ratios of the extensibility are estimated as 0.22 for the crossbridge, 0.26 for the myosin filament and 0.52 for the actin filament, in consistency with the values determined by X-ray diffraction by Wakabayashi et al. (1994).
The Soil Microbial Community and Grain Micronutrient Concentration of Historical and Modern Hard Red Spring Wheat Cultivars Grown Organically and Conventionally in the Black Soil Zone of the Canadian Prairies
Authors: Nelson Alison G. , Quideau Sylvie A. , Frick Brenda , Hucl Pierre J. , Thavarajah Dil , Clapperton M. Jill , Spaner Dean M.
Published: March 2011

Micronutrient deficiencies in the diet of many people are common and wheat is a staple food crop, providing a carbohydrate and micronutrient source to a large percentage of the world’s population. We conducted a field study to compare five Canadian red spring wheat cultivars (released over the last century) grown under organic and conventional management systems for yield, grain micronutrient concentration, and soil phospholipid fatty acid (PLFA) profile. The organic system had higher grain Zn, Fe, Mg and K levels, but lower Se and Cu levels. There was no trend in the results to suggest that modern western Canadian hard red spring cultivars have lower grain micronutrient content than historical cultivars. Wheat cultivar choice is important for maximizing grain nutrient levels, which was influenced by management system. It is evident that the emphasis on elevated grain quality in the western Canadian hard red spring class has resulted in the retention of micronutrient quality characters. Three fungal PLFAs were indicators for the organic system, and all three of these indicators were positively correlated with grain Cu concentration. In the organic system, percent arbuscular mycorrhizal fungi were negatively correlated with grain Zn and Fe concentrations, and positively correlated with grain Mn, Cu, K concentrations and grain yield. The organic system had higher levels of fungi in the soil, including arbuscular mycorrhizal fungi. Organic management practices appear to result in elevated levels of grain micronutrient concentration. The hard red spring breeding effort in and for the black soil zone of the northern Great Plains also appears to have led to no diminishment of grain micronutrient concentration. It is evident that both the agronomic system and breeding strategies in this region can be exploited for future increases in grain micronutrient concentration.
Le suffixe adjectival –ble : Impacts sémantique et syntaxique de la dérivation
Authors: Schuwer Martine
Published: March 2011

L’objectif de cette étude est de mesurer l’apport sémantique et l’impact syntaxique de la dérivation dans les adjectifs en -ble réputés syntaxiquement contraints, certains figurant obligatoirement en épithète, d’autres en attribut. On pose l’hypothèse que le comportement syntaxique différencié est lié à trois facteurs : au type de base suffixé, aux propriétés du référent que l’adjectif dérivé modifie ; enfin à la nature de la relation que le suffixe établit entre la base dérivante et le nom-support.
Investigation of Differences in P53 Gene Polymorphisms between Schizophrenia and Lung Cancer Patients in the Turkish Population
Authors: Özbey Ulku , Yüce Hüseyin , Namli Mustafa , Elkiran Tamer
Published: March 2011

Objective. The reduced incidence of cancer observed in schizophrenia patients may be related to differences in genetic background. It has been suggested that genetic predisposition towards schizophrenia is associated with reduced vulnerability to lung cancer, and p53 gene is one of the candidate genes. In our study, we aimed to investigate polymorphisms in the BstUI in exon 4 and MspI in intron 6 restriction sites of the p53 gene in Turkish schizophrenia patients, lung cancer patients, and controls. Material and Methods. Allele and genotype incidence of these polymorphisms with their haplotype combinations were studied in 100 Turkish lung cancer and schizophrenia patients and 100 controls without malignant and schizophrenia diseases. The genotype characteristics were determined by PCR-based RFLP method using DNA extracted from peripheral blood. Results. For the BstUI and MspI polymorphism, there were found significant differences in the genotype and allele frequencies between schizophrenia and lung cancer patients with control groups (P<.01). The analysis based on haplotype frequencies showed the presence of BstUI-MspI 2-1 haplotype in cancer patients (12%) in contrast to the absence of this haplotype in schizophrenia and controls. Only in lung cancer patients we found both significant decrease of A1 allele of the p53 codon 72 (OR 0.23, 95% CI 0.9–0.58) and A1/A1 homozygous genotype (P<.0001, OR 0.19). Conclusion. The results of this study suggest a protective effect of A1 allele against lung cancer, and the p53 MspI polymorphism may modify the susceptibility to lung cancer as a single factor rather than in combination with BstUI polymorphism.
Women with Heart Failure Are at High Psychosocial Risk: A Systematic Review of How Sex and Gender Influence Heart Failure Self-Care
Authors: Thomas Jody R. , Clark Alexander M.
Published: March 2011

To improve patient support, it is important to understand how people view and experience Heart Failure (HF) self-care. This systematic review of qualitative studies included all published studies that examine the influence of sex and gender on HF self-care. A systematic search was done for papers (1995–2010) indexed in Ovid MEDLINE, Ovid Medline, Ovid EMBASE, Ovid PsycINFO, CSA Sociological Abstracts, OVID AARP Ageline, EBSCO Academic Search Complete, EBSCO CINAHL, EBSCO SocINDEX, ISI Web of Science: Social Sciences Citation Index and Science Citation Index Expanded, and Scopus. After screening of 537 citations, six qualitative studies identified that differences existed in perceptions of symptoms with women having less family involvement and psychosocial support around self-care. Moreover, women had considerably more negative views of the future, themselves and their ability to fulfill social self-care roles. Women with HF represent a highly vulnerable population and need more support for psychosocial wellbeing and self-care.
On the Arthur–Selberg trace formula for $\mathrm{GL}(2)$
Authors: Finis Tobias , Lapid Erez
Published: March 2011

We extend the terms on the geometric side of the trace formula for

\mathrm{GL}(2)

over

\mathbb{Q}

continuously to a natural Fréchet algebra of non-compactly supported test functions. For the spectral side the analogous result had been obtained previously (in much greater generality) in collaboration with W. Müller.
Powers in finite groups
Authors: Nikolov Nikolay , Segal Dan
Published: March 2011

If

G

is a finitely generated profinite group then the verbal subgroup

G^{q}

is open. In a

d

-generator finite group every product of

q

th powers is a product of

f(d,q)

q

th powers.
Stabilization of the Schrödinger equation with a delay term in boundary feedback or internal feedback
Authors: Nicaise Serge , Rebiai Salah-eddine
Published: March 2011

In this paper, we investigate the effect of time delays in boundary or internal feedback stabilization of the Schrödinger equation. In both cases, under suitable assumptions, we establish sufficient conditions on the delay term that guarantee the exponential stability of the solution. These results are obtained by using suitable energy functionals and some observability estimates.
Late Effect of the Cervical Irradiation on Periodontal Status and Cariogen Flora in Hodgkin Lymphoma Patients
Authors: Simon Zsófia , Tar Ildikó , Gáll Katalin , Ivancsó Borbála , Szabó Judit , Illés Árpád
Published: March 2011

Cervical radiotherapy may leads to elevated caries risk in Hodgkin-lymphoma (HL) patients. Our aim was to estimate the late effect of cervical irradiation on periodontal status in HL patients. Patients filled out query-form, their clinical data were collected, periodontal status was examined, decayed-missing-filled-teeth and periodontal-indexes were calculated. We examined 68 patients who received, 64 patients who did not received cervical radiotherapy and 51 control person. 23.5% of cervical irradiated, 18.15% of not irradiated patients and 17.64% of controls had subjective xerostomia, but it was not objective by sialometry. Mean decayed-missing-filled-teeth-index was 22.53 among irradiated, 21.54 among not irradiated patients while it was 17.23 in control group. Periodontal index was 2.47, 2.42, and 2.14 in different groups. Difference between decayed-missing-filled-teeth indexes of irradiated patients and controls was significant. We have to emphasize the importance of prevention and closer dental observation of HL patients.
Administering GBrowse Sites with WebGBrowse
Authors: Podicheti Ram , Dong Qunfeng
Published: March 2011

GBrowse is widely used by biologists to visualize genome annotation. We have developed WebGBrowse to facilitate hosting multiple GBrowse instances specific for different users on the same Web server. WebGBrowse automatically sets up each user‐specific GBrowse instance by extracting information from user‐supplied data to produce the appropriate configuration. This unit describes installation and administration of WebGBrowse for bioinformaticians who plan to manage local WebGBrowse servers in their institutions.Curr. Protoc. Bioinform. 33:9.14.1‐9.14.9. © 2011 by John Wiley & Sons, Inc.
Next Generation Sequence Assembly with AMOS
Authors: Treangen Todd J. , Sommer Dan D. , Angly Florent E. , Koren Sergey , Pop Mihai
Published: March 2011

A Modular Open‐Source Assembler (AMOS) was designed to offer a modular approach to genome assembly. AMOS includes a wide range of tools for assembly, including the lightweight de novo assemblers Minimus and Minimo, and Bambus 2, a robust scaffolder able to handle metagenomic and polymorphic data. This protocol describes how to configure and use AMOS for the assembly of Next Generation sequence data. Additionally, we provide three tutorial examples that include bacterial, viral, and metagenomic datasets with specific tips for improving assembly quality.Curr. Protoc. Bioinform. 33:11.8.1‐11.8.18. © 2011 by John Wiley & Sons, Inc.
Halide removal from coal‐derived syngas: review and thermodynamic considerations
Authors: Dolan Michael D. , Ilyushechkin Alex Y. , McLennan Keith G. , Sharma Sunil D.
Published: March 2011

Halide species are one of the most abundant and damaging impurities in syngas derived from coal. Aside from environmental concerns, halides can cause irreversible damage to downstream processes such as particulate filters, catalysts, gas separation membranes, fuel cells and turbines. The current trend towards high‐temperature, dry gas cleaning is making solid sorbents increasingly favourable, and sorbent development must take into consideration the chemical, physical, efficiency and economic aspects of sorbent performance. This article reviews the origins of halides in coals, cleaning requirements and efforts to develop solid sorbents for halide removal for gasification processes. Most research effort to date has concerned (1) the performance and optimization of basic sorbents such as calcium and sodium carbonate and (2) determining the tolerances of catalysts, filters, fuel cells and other plant components to halide impurities. In addition, thermodynamic calculations have been used to compare the performance of a large number of potential sorbents examined using criteria such as conversion, speciation, volatility and regenerability. This exercise confirms alkali and alkaline earth carbonates exhibit the greatest halide conversion at the temperatures demanded by various downstream processes, but these species are not regenerable at high temperatures in the same manner as desulfurization sorbents. Although not previously investigated, scope exists for the investigation of barium carbonate for halide sorption. Halide removal is best performed preceding sulfur removal due to the irreversible inhibition of regenerable desulfurization sorbents by halide species. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.