Dispersion statistics and a sampling plan for Helicoverpa (Lepidoptera : Noctuidae) on fresh-market tomatoes (Lycopersicon esculentum)

Helicoverpa spp. is the primary pest in the Australian fresh-market tomato industry. We describe the spatial distribution of Helicoverpa spp. eggs on fresh-market tomato crops in the Goulburn Valley region of Victoria, and present a sequential sampling plan for monitoring population densities. The distribution of Helicoverpa spp. eggs was highly contagious, as indicated by a Taylor's b-value of 1.59. This high level of contagion meant that relatively large sample sizes would need to be collected to obtain an estimate of population density. High-precision sampling plans generally necessitated impractical sample sizes, and thus the plan we present is a relatively low-precision level plan (SE/mean = 0.3). Nonetheless, this level of precision is considered adequate for most agronomic scenarios. The plan was validated using a statistical re-sampling approach. The level of precision achieved was generally close to the nominal level. Likewise, the number of samples collected generally showed little departure from the theoretically calculated minimum sample size.

Global and regional dispersion of publishing in the field of international marketing

This paper empirically examines the research productivity of academic institutions in the leading international marketing journals, leading generalist marketing journals, and leading international business journals between the years 1999 and 2003 from a regional and country-specific perspective. The research found that across the three groups of journals, the majority of works were authored by academics at institutions located in North America, although North Americans contribute significantly less in the international marketing and international business journals than leading generalist marketing journals. The findings suggest that there is a broadening of non-U.S. influence within the international marketing and international business journals, which should lead to a broadening of international marketing theory.

Immunostimulatory polysaccharides from Chlorella pyrenoidosa. A new galactofuranan. Measurement of molecular weight and molecular weight dispersion by DOSY NMR.

Fractionation of the hot water extract of Chlorella pyrenoidosa was performed using a combination of ethanol precipitation, size exclusion chromatography, and anion exchange chromatography. One fraction contained a new polysaccharide, and this compound was shown to be a 1→2-linked β-d-galactofuranan from its 1D and 2D 1H and 13C NMR spectra, with a molecular weight of 15 kDa from DOSY NMR measurements. A number of other fractions were shown to have the same repeating unit as the previously identified arabinogalactan. However, arabinogalactans from different fractions were shown by DOSY NMR to have different molecular weights, which ranged from 27 to 1020 kDa. Agreement with molecular weights measured for some of these fractions by SEC-MALS was very good, further confirming the relationship established by Viel et al. between molecular weights of neutral polysaccharides and self-diffusion coefficients. The smaller molecular weight polysaccharides, the galactofuranan and the 27 and 50 kDa arabinogalactans, were shown to be close to monodisperse by analysis of the distributions of the self-diffusion coefficients for the polymers. The larger arabinogalactans had considerable variation in their molecular weights (188 ± 109 kDa and 1020 ± 370 kDa). Only the two larger arabinogalactans showed immunostimulatory activity.

Dispersion of information or market behaviour : general public trading in S & P 500 index futures

This paper considers 15 minute records of trading volume and traded prices coinciding with the reporting intervals required by the Commodity Futures Trading Commission. Records are extracted from trade records for two way trade between market makers (CTI1) and the general public (CTI4) from January 1994 to June 2004. Futures price records are matched with S&P500 cash index price records. Simultaneous volatility models are specified and estimated to test trading volume to futures volatility lead/lag effects and also futures volatility to cash index volatility lead/lag effects. There is evidence that existing theoretical models of the general public trading behaviour do not explain such behaviour in these very actively traded markets. These effects can depend more on market conditions than what is suggested in theoretical models.

Dispersion characterization of Mechanochemically Synthesized nanoparticles using UV/Vis Spectroscopy

Dispersion characterization of nanoparticles was carried out using UV/Vis spectroscopy. ZnO and CeO2 nanoparticles of sizes ranging 10 - 250 nm were investigated for slurries having various concentrations. The particles were synthesized by mechanochemical processing, which allows the formation of agglomeration-free nanoparticles. It was found that the UV/Vis spectra were highly sensitive to mean particle sizes and agglomeration states. The results showed that UV/Vis spectroscopy is a highly promising technique for studying nanoparticle dispersions having a wide range of concentrations in various media.

The idiosyncratic movement potential of the dancer's subject body in the work "Deep map"

An investigation into choreographic processes employed within contemporary modern dance. This involved the exploration of working methods used in the making of "Deep map" nos.1, 2 & 3, presented in Melbourne from 1997-2000. The focus of that method was the placement of the dancer as 'subject' whilst maintaining the role of the choreographer as 'auteur'.

Dispersion of boron nitride nanotubes in aqueous solution with the help of ionic surfactants

We report that ammonium oleate surfactants can help the dispersion of multiwalled boron nitride nanotubes (BNNTs) in water to form a BNNT solution stable for several months, which was due to the non-covalent functionalization of nanotube surfaces. Fourier Transform Infrared Spectroscopy (FTIR) and Photoluminescence (PL) analysis with synchrotron radiation source revealed that this BNNT aqueous solution preserves the intrinsic optical properties of BNNTs. © 2009 Elsevier Ltd. All rights reserved.

Improving the dispersion and mechanical properties of epoxy/carbon nanotube composites

The incorporation and uniform dispersion of carbon nanotubes (CNTs) in polymer matrix could facilitate engineers to create high performance nanocomposites that potentially compete with most advanced materials in nature. The unique combination of outstanding mechanical, thermal, and electrical properties of CNTs makes them excellent nanofillers for the fabrication of advanced materials. Successful enhancement in mechanical properties via reinforcement is expected only when the nanofillers are well dispersed in the polymer matrix. Moreover, the orientation as well as the CNT/matrix interfacial strength also determines the effective physical properties of the nanocomposites. However, CNTs typically assemble to give bundles, which are heavily entangled to each other with a high aspect ratio and a large π-electronic surface. In this work, we outline some preliminary results in preparing high performance epoxy composites. Composites with fine dispersion and superior mechanical properties were prepared using epoxy and multiwalled carbon nanotubes (MWCNTs). The fine dispersion of the nanocomposites can be identified in the high resolution SEM image shown in Figure 1. This method can provide an alternative route for the preparation of new structural and functional nanocomposites.

Least squares asymptotics in spurious and cointegrated panel regressions with common and idiosyncratic stochastic trends

This article makes an analytical study of the effects of the presence of both common and idiosyncratic stochastic trends on the pooled least squares estimator. The results suggest that the usual result of asymptotic normality depends critically on the absence of the common stochastic trend.

On the welfare gains of price dispersion

Can price dispersion be associated with higher levels of welfare? To answer we compare two economies that differ only in the way prices are formed. In the first, sellers post a unique price–quantity pair, with no price dispersion. In the second, sellers post a quantity only and let prices be determined ex post by realized demand, resulting in price dispersion. We show that while agents trade lower quantities when prices are dispersed (an intensive margin effect), they also trade more often (an extensive margin effect). At low inflation, the extensive margin dominates making agents better off with price dispersion.

Inflation and quality dispersion

One questionable aspect of price posting with directed search is the strong commitment by sellers to commit to the advertised terms of trade. In this paper I explore the welfare implications of assuming that sellers cannot commit and vary the quality of their output ex post according to realized demand. I show that such lack of commitment translates into lower participation by buyers, lower average quality, and a consumption-equivalent loss of 0.3% of annual GDP.

Individual dispersion of carbon nanotubes in epoxy via a novel dispersion-curing approach using ionic liquids

The effective dispersion of carbon nanotubes (CNTs) in a thermoset was achieved using ionic liquid as the dispersion-curing agent. We preferentially dispersed multiwalled carbon nanotubes (MWCNTs) down to individual tube levels in epoxy resin. Here the dispersion is ruled by the depletion of physical bundles within the MWCNT networks, for which molecular ordering of ionic liquids is considered responsible. The quantitative analyses using ultra small angle X-ray scattering (USAXS) confirmed the dispersion of individual MWCNTs in the matrix. The distance between the dispersed nanotubes was calculated at different nanotube loadings using the power law fitting of the USAXS data. The fine dispersion and subsequent curing, both controlled by ionic liquid, lead to composites with substantially enhanced fracture mechanical and thermomechanical properties with no reduction in thermal properties. Merging processing techniques of nanocomposites with ionic liquid for efficient dispersion of nanotubes and preferential curing of thermosets facilitates the development of new, high performance materials.

Molecular-level dispersion of graphene into epoxidized natural rubber: Morphology, interfacial interaction and mechanical reinforcement

The interfacial interaction of composites dominates the properties of polymeric/inorganic nanocomposites. Herein, epoxy and hydroxyl groups are introduced into the natural rubber (NR) molecular chains to anchor oxygenous functional groups on the surface of graphene oxide (GO) sheets and therefore enhance the interfacial interaction between GO and rubber. From the morphological observation and interaction analysis, it is found that epoxidized natural rubber (ENR) latex particles are assembled onto the surfaces of GO sheets by employing hydrogen bonding interaction as driving force. This self-assembly depresses restacking and agglomeration of GO sheets and leads to homogenous dispersion of GO within ENR matrix. The formation of hydrogen bonding interface between ENR and GO demonstrates a significant reinforcement for the ENR host. Compared with those of pure ENR, the composite with 0.7 wt% GO loading receives 87% increase in tensile strength and 8.7 fold increase in modulus at 200% elongation after static in-situ vulcanization.

An improved understanding of the dispersion of multi-walled carbon nanotubes in non-aqueous solvents

The homogeneous and stable dispersion of carbon nanotubes (CNTs) in solvents is often a prerequisite for their use in advanced materials. Dispersion procedures, reagent concentration as well as the interactions among reagent, defective CNTs and near-perfect CNTs will affect the resulting CNT dispersion properties. This study, for the first time, presents a detailed comparison between two different approaches for dispersing CNTs. The results enhance our understanding of the interactions between surfactant, defective CNTs and near-perfect CNTs and thus provide insight into the mechanism of CNT dispersion. Dispersions of "as-produced" short multi-walled carbon nanotubes (MWCNTs) in N,N-dimethylformamide were prepared by two different surfactant (Triton X-100) assisted methods: ultrasonication and ultrasonication followed by centrifugation, decanting the supernatant and redispersing the precipitate. Visual observation and UV-visible spectroscopy results showed that the latter method produce a more stable dispersion with higher MWCNT content compared to dispersions produced by ultrasonication alone. Transmission electron microscopy and Raman spectroscopic investigations revealed that the centrifugation/ decanting step removed highly defective nanotubes, amorphous carbon and excess surfactant from the readily re-dispersible near-perfect CNT precipitate. This is contrary to other published findings where the dispersed MWCNTs were found in the supernatant. Thermogravimetric analysis showed that 95 % of Triton X-100 was removed by centrifugation/decanting step, and the remainder of the Triton X-100 molecules is likely randomly adsorbed onto the MWCNT surface. Infrared spectral analysis suggests that the methylene groups of the polyoxyethylene (aliphatic ether) chains of the residual Triton X-100 molecules are interacting with the MWCNTs. © 2014 Springer Science+Business Media.