bluuebunny/crossref_metadata_2025 huggingface dataset:
Dirac structures and generalized complex structures on
Authors: Vaisman Izu
Published: June 2007

We consider Courant and Courant–Jacobi brackets on the stable tangent bundle TM × ℝ
h
of a differentiable manifold and corresponding Dirac, Dirac–Jacobi and generalized complex structures. We prove that Dirac and Dirac–Jacobi structures on TM × ℝ
h
can be prolonged to TM × ℝ
k
, k > h, by means of commuting infinitesimal automorphisms. Some of the stable generalized complex structures are a natural generalization of the normal almost contact structures; they are expressible by a system of tensors (P, θ, F, Za
, ξ
a
) (a = 1, …, h), where P is a Poisson bivector field, θ is a 2-form, F is a (1, 1)-tensor field, Za
are vector fields and ξ
a
are 1-forms, which satisfy conditions that generalize the conditions satisfied by a normal almost contact structure (F, Z, ξ). We prove that such a generalized structure projects to a generalized complex structure of a space of leaves and we characterize the structure by means of the projected structure and of a normal bundle of the foliation. Like in the Boothby–Wang theorem about contact manifolds, principal torus bundles with a connection over a generalized complex manifold provide examples of this kind of generalized normal almost contact structures.
(Nicht)Flexion des Substantiv(s). Neue Überlegungen zum finiten Substantiv / (Non)inflection of the substantive. New thoughts on the finite substantive
Authors: Ágel Vilmos
Published: June 2007

The current article aims at an adequate description and a plausible explanation of the inflecting and non-inflecting behavior of substantives in modern German. The concept of the (in)finite substantive forms the theoretical framework of the study. Typological and language-historical arguments are brought forward which support the theory that the form of the respective gender realization motivates the form of the respective case realization. Since the realization of gender is periphrastic in the singular and synthetic in the plural, the realization of case is respectively also periphrastic and synthetic. The argumentation calls for, among other things, a new approach to gender. It is assumed that the categorization of gender is not limited to the singular, but rather also extends to the plural. The system of plural marking – with the exception of the
Characterization of components of nano-energetics by small-angle scattering techniques
Authors: Mang Joseph T. , Hjelm Rex P. , Son Steven F. , Peterson Paul D. , Jorgensen Betty S.
Published: June 2007

Small-angle scattering (SAS) and ultra small-angle scattering techniques, employing x-rays and neutrons, were used to characterize six different aluminum nanopowders and nanopowders composed of molybdenum trioxide and tungsten trioxide nanoparticles. Each material has different primary particle morphology and aggregate and agglomerate geometry, and each is important to the development of nano-energetic materials. The combination of small-angle and ultra small-angle techniques allowed a wide range of length scales to be probed, providing a more complete characterization of the materials. For the aluminum-based materials, differences in the scattering of x-rays and neutrons from aluminum and aluminum oxide provided sensitivity to the metal core and metal oxide shell structure of the primary nanoparticles. Small-angle scattering was able to discriminate between particle size and shape and agglomerate and aggregate geometry, allowing analysis of both aspects of the structure. Using the results of these analyses and guided by scanning electron microscopy (SEM) images, physical models were developed, allowing for a quantitative determination of particle morphology, mean nanoparticle size, nanoparticle size distribution, surface layer thickness, and aggregate and agglomerate fractal dimension. Particle size distributions calculated using a maximum entropy algorithm or by assuming a log-normal particle size distribution function were comparable. Surface area and density determinations from the small-angle scattering measurements were comparable to those obtained from other, more commonly used analytical techniques: gas sorption using Brunauer–Emmett–Teller analysis, thermogravimetric analysis, and helium pycnometry. Particle size distribution functions derived from the SAS measurements agreed well with those obtained from SEM.
ZnO submicron structures of controlled morphology synthesized in zinc-hexamethylenetetramine-ethylenediamine aqueous system
Authors: Gao Xiang-Dong , Li Xiao-Min , Zhang Sam , Yu Wei-Dong , Qiu Ji-Jun
Published: June 2007

The morphology of ZnO submicron crystals formed in a weak alkaline environment (pH value less than 11.0) was systematically studied for the first time. ZnO submicron particles with different morphologies (flowers, rod, and wire) were synthesized from an aqueous solution by adopting ethylenediamine as the source of hydroxyl group, hexamethylenetetramine (HMT) as the additive, and potassium chloride (KCl) as the background electrolyte. The effects of primary experimental parameters such as HMT and KCl addition, precursor concentration, and reaction temperature on the microstructure, crystallinity of the resultant particles, and their distribution on substrate are discussed in this paper. In the flowerlike structure, the particle size is more controlled by the precursor concentration, and the microstructure is modulated by increasing the concentration of HMT and the reaction temperature. The introduction of ZnO seed layer on substrate promotes even distribution of ZnO flowers. High concentration KCl electrolyte inhibits formation of the flowerlike structure and promotes the growth of submicron ZnO crystals in rod or wire shape. Mechanism studies indicate that the degree of supersaturation of Zn(OH)2 and the adsorption of organic/inorganic species on the surface of ZnO are the prime factors influencing the nucleation, growth rate, and eventual morphology.
Fabrication and characterization of mesoporous borosilicate glasses with different boron contents
Authors: Xiu Tongping , Liu Qian , Wang Jiacheng
Published: June 2007

A series of wormhole-like mesoporous borosilicate glasses (MBSGs) with different compositions has been prepared by a combination of surfactant templating, sol-gel methods, and evaporation-induced self-assembly processes. Small-angle x-ray diffraction, high-resolution transmission electron microscopy, and N2 sorption isotherms analysis showed that all the MBSGs prepared possess the mesoporous structure. However, the stability of the mesoporous structure is strongly affected by the boron contents. When boron content was increased, boric acid was found in the final product, and the mesoporous structure was partially degraded. The formation and loss of boric acid through the whole process may account for the partial collapse of the mesostructure.
Low-Salinity Resistance of Juvenile Cobias
Authors: Burkey K , Young S P , Smith T I J , Tomasso J R
Published: June 2007

Juvenile cobias Rachycentron canadum were exposed to decreasing salinity (∼1‰ per day) in a series of five experiments to assess their low-salinity resistance. All fish survived for 24 h at a salinity of 2‰, but 73% died within 24 h of a reduction to 1‰ salinity. Plasma osmolality decreased significantly with decreasing salinity. Fish held for 7 d at 2, 5, or 8‰ after an approximately 1‰ daily reduction differed significantly in plasma osmolality; fish held at a salinity of 2‰ exhibited significantly lower plasma osmolality than fish in the other treatments. Doubling the environmental Ca concentration did not affect plasma osmolality. The results indicate that cobias have limited euryhaline abilities but not enough to sustain low-salinity culture operations.
100‐MHz CMOS circuits directly fabricated on plastic using sequential laterally solidified silicon
Authors: Kane Michael G. , Goodman Lawrence , Firester Arthur H. , van der Wilt Paul C. , Limanov Alexander B. , Im James S.
Published: June 2007

Abstract— CMOS TFT circuits were fabricated on plastic using sequential laterally solidified silicon combined with a low‐temperature CMOS process. The unity‐gain frequencies of the best of NMOS TFTs are greater than 250 MHz, and the CMOS ring oscillators operate at 100 MHz. To the best of the authors' knowledge, these are the highest‐frequency circuits ever fabricated directly on plastic. This high‐performance CMOS‐on‐plastic process can be applied to the fabrication of AMLCD integrated drivers and AMOLED pixels on plastic substrates.
All‐additive ink‐jet‐printed display backplanes: Materials development and integration
Authors: Arias Ana C. , Daniel Jürgen , Krusor Brent , Ready Steve , Sholin Veronica , Street Robert
Published: June 2007

Abstract— Methods used to deposit and integrate solution‐processed materials to fabricate TFT backplanes by ink‐jet printing are discussed. Thematerials studied allow the development of an all‐additive process in which materials are deposited only where their functionality is required. The metal layer and semiconductor are printed, and the solution‐processed dielectric is spin‐coated. Silver nanoparticles are used as gate and datametals, the semiconductor used is a polythiophene derivative (PQT‐12), and the gate dielectric is an epoxy‐based photopolymer. The maximum processing temperature used is 150°C, making the process compatible with flexible substrates. The ION/IOFF ratio was found to be about 105−106, and TFT mobilities of 0.04 cm2/V‐sec were obtained. The influence of surface treatments on the size and shape of printed features is presented. It is shown that coffee‐stain effects can be controlled with ink formulation and that devices show the expected pixel response.
Transflective twisted‐nematic liquid‐crystal display with double twisted‐nematic cell and twisted liquid‐crystal retarder
Authors: Mak Hin Yu , Chigrinov Vladimir G. , Kwok Hoi‐Sing
Published: June 2007

Abstract— Two configurations, (i) a double‐cell‐gap twisted nematic (DTN) liquid‐crystal display (LCD) and (ii) a single‐cell‐gap twisted‐nematic (TN) liquid‐crystal display (LCD) using a twisted LC retarder, were optimized for transflective liquid‐crystal displays. For the DTN configuration, both the single‐cell‐gap approach and the double‐cell‐gap approach were considered. The optimized configurations exhibit a high contrast ratio, wide viewing angles, and achromatic (black/white) switching in both the transmissive and reflective modes. They are easy to fabricate and also possess a perfect dark state. Both are suitable for high‐quality transflective TFT‐LCDs.
Application of the neuroblastoma assay for paralytic shellfish poisons to neurotoxic freshwater cyanobacteria: Interlaboratory calibration and comparison with other methods of analysis
Authors: Humpage Andrew R. , Ledreux Aurélie , Fanok Stella , Bernard Cécile , Briand Jean-François , Eaglesham Geoff , Papageorgiou John , Nicholson Brenton , Steffensen Dennis
Published: June 2007

Paralytic shellfish poisons (PSPs) are produced by freshwater cyanobacteria and pose a threat to human and animal drinking-water supplies. The wide range of toxin analogues (and the likelihood that further analogues remain to be discovered) means that chromatographic methods are not always reliable indicators of toxicity. Although the mouse bioassay remains the method of choice in the seafood industry, its use is increasingly being questioned on ethical grounds. The cell-based Neuro-2A neuroblastoma toxicity assay is an alternative bioassay validated for testing shellfish extracts, so it was of interest to determine its applicability with the different suite of toxin analogues produced by cyanobacteria. Cyanobacterial bloom samples from Australia, Brazil, and France were assayed using the neuroblastoma assay, liquid chromatography—tandem mass spectrometry (LC-MS/MS), high-performance liquid chromatography with postcolumn derivatization and fluorescence detection, and the Jellett Rapid Test for PSP™. To assess interlaboratory variability, the neuroblastoma assay was set up in laboratories in Paris (France) and Adelaide (Australia). Neuroblastoma and chromatographic methods gave comparable results except in the case of the neurotoxic Brazilian samples: LC-MS/MS did not detect the putative new PSPs contained in these samples. Inter- and intralaboratory variability of the neuroblastoma assay was typical of biological assays but no greater than that found for interassay variability between different chromatographic determinations. The batch of Jellett Rapid Tests for PSP used did not yield quantitative results. Overall, the neuroblastoma assay was useful as a screening assay for determination of toxicity caused by saxitoxin neurotoxins in freshwater cyanobacteria, having the advantage of being sensitive to unidentified toxins that currently cannot be quantified by chromatographic means.
Comparison of hardness- and chloride-regulated acute effects of sodium sulfate on two freshwater crustaceans
Authors: Soucek David John
Published: June 2007

Based on previous observations that hardness (and potentially chloride) influences sodium sulfate toxicity, the objective of the current study was to quantify the influence of both chloride and water hardness on acute toxicity to Hyalella azteca and Ceriodaphnia dubia. In addition, observed toxicity data from the present study were compared to toxicity predictions by the salinity/toxicity relationship (STR) model. Hardness had a strong influence on sulfate toxicity that was similar for both crustaceans, and nearly identical median lethal concentration (LC50)/hardness slopes were observed for the two species over the tested range. Chloride had a strong but variable influence on sulfate acute toxicity, depending on the species tested and the concentration range. At lower chloride concentrations, LC50s for H. azteca strongly were correlated positively with chloride concentration, although chloride did not affect the toxicity of sodium sulfate to C. dubia. The opposite trend was observed over the higher range of chloride concentrations where there was a negative correlation between chloride concentration and sulfate LC50 for both species. The widely ranging values for both species and a high correlation between LC50s in terms of sulfate and conductivity suggested that, whether based on sulfate, conductivity, or total dissolved solids (TDS), attempts at water quality standard development should incorporate the fact that water quality parameters such as hardness and chloride strongly influence the toxicity of high TDS solutions. The STR model predicted toxicity to C. dubia relatively well when chloride was variable and hardness fixed at approximately 100 mg/L; however, the model did not account for the protective effect of hardness on major ion/TDS toxicity.
Cadmium accumulation in herbivorous and carnivorous small mammals: Meta-analysis of field data and validation of the bioaccumulation model optimal modeling for ecotoxicological applications
Authors: Veltman Karin , Huijbregts Mark A. J. , Hamers Timo , Wijnhoven Sander , Hendriks A. Jan
Published: June 2007

Environmental risk assessment procedures often use bioaccumulation as a criterion for hazard identification of a polluted location. Field studies regarding metal concentrations in food chains, however, have provided widely different information, because accumulation is shown to vary between the extremes of bioreduction and biomagnification. Bioaccumulation models provide insight regarding species-specific uptake and elimination kinetics of metals and assist in the interpretation of field data. Here, we use the bioaccumulation model OMEGA (Optimal Modeling for Ecotoxicological Applications) to estimate cadmium accumulation in herbivorous voles and carnivorous shrews. In addition to model validation, a meta-analysis of cadmium accumulation data is performed, because earlier studies generally have focused on relationships between cadmium concentrations in either specific tissues (kidney and liver) or whole-body concentrations and total soil levels. Additionally, we included the food—small mammal relationship. Our results show that cadmium whole-body concentrations are significantly related to cadmium levels in food items such as earthworms and plants. In addition, a significant relationship is found between cadmium accumulation in the liver and kidney of small mammals and total soil levels. Cadmium concentrations in shrews typically are an order of magnitude higher than metal levels in voles as a result of higher metal accumulation in earthworms compared to plants. Model predictions for both voles and shrews are in good agreement with field observations; deviations generally are within a factor of five. Small mammals prevent cadmium toxicity by binding this metal to metallothionein, which likely results in low elimination rates. Comparison with empirical elimination rates shows that rate constants of loss are accurately predicted assuming that cadmium is only released via growth dilution.
What Does Undergraduate Enrollment in Soil and Crop Sciences Mean for the Future of Agronomy?
Authors: Hansen Neil , Ward Sarah , Khosla Raj , Fenwick Jack , Moore Bill
Published: June 2007

Soil and crop science programs at land‐grant colleges have historically relied on appropriated funding from state and federal sources and tuition to support the tripartite mission of research, extension, and teaching. However, due to declining funding from state and federal sources, tuition and fees are becoming increasingly important sources. As tuition revenue becomes more important, student enrollment becomes a greater concern. Undergraduate enrollment in soil and crop sciences across the USA has been in decline for the last two decades. We collected current enrollment statistics by submajor areas of focus at all 50 of the 1862 land‐grant universities. We also evaluated organizational structure, college and department names, and undergraduate tuition and fees. Enrollment in all soil and crop science related majors averaged 90 students per university, with the majority of students (36%) in landscape, horticulture, and turfgrass programs. A projected total of fewer than 350 students per year from all 50 of the institutions surveyed will graduate from programs with a traditional agronomy focus that integrates multiple aspects of crop production and management. Declining enrollment in soil and crop science programs has been accompanied by significant changes in the structure and identity of the academic units that house them. Despite declining enrollment, there is still strong demand for teaching the substance of soil and crop sciences at U.S. land‐grant institutions, and employment prospects for agricultural graduates are good. The current socioeconomic environment necessitates adaptation of soil and crop science programs, including formation of new and innovative areas of study, expanded participation by the soil and crop sciences in interdisciplinary programs, and the possibility of regional cooperation and specialization among academic institutions. New entrants coming into the field of professional agronomy as researchers, professors, advisors, and consultants will increasingly be the products of interdisciplinary college programs where they are mixed with nonagricultural students and have taken classes from nonagricultural faculty.
Theory and Application of Landfarming to Remediate Polycyclic Aromatic Hydrocarbons and Mineral Oil‐Contaminated Sediments; Beneficial Reuse
Authors: Harmsen J. , Rulkens W.H. , Sims R.C. , Rijtema P.E. , Zweers A.J.
Published: June 2007

When applying landfarming for the remediation of contaminated soil and sediment, a fraction of the soil‐bound contaminant is rapidly degraded; however, a residual concentration may remain, which slowly degrades. Degradation of polycyclic aromatic hydrocarbons (PAHs) and mineral oil can be described using a multi‐compartment model and first‐order kinetics, in which three degradable fractions are distinguished; (1) rapid, (2) slowly, and (3) very slowly degradable. Using this model populated with data from long‐term experiments (initiated in 1990), it is shown that time frames from years to decades can be necessary to clean the soil or sediment to obtain a target below regulatory guidelines. In passive landfarms without active management, three principal potentially limiting factors can be identified: (1) availability of appropriate microorganisms, (2) supply of oxygen for the biodegradation process, and (3) bioavailability of the pollutants to the microorganisms. Bioavailable PAHs and mineral oil are readily biodegradable contaminants under aerobic conditions, and presence and activity of microorganisms are not problems. The other two factors can be limiting and are theoretically described. Using these descriptions, which are in agreement with field experiments of 10 to 15 yr, it is shown if and when optimization of the biodegradation process is an option. Because a long time period is necessary to degrade the slowly and very slowly degradable fractions, passive landfarming should be combined with beneficial use of the land area. Examples include the development of natural environments, use in constructions, growing of biomass for energy production, including biofuels, and use as cover for landfills.
Changes in Microbial Biomass Parameters of a Heavy Metal‐Contaminated Calcareous Soil during a Field Remediation Experiment
Authors: Clemente R. , de la Fuente C. , Moral R. , Bernal M. P.
Published: June 2007

Soil microbial biomass parameters give useful information about the restoration degree and quality of contaminated soils. These parameters were studied in a field experiment where the effect of two organic amendments on the bioavailability of heavy metals in an agricultural soil and on their accumulation in Beta vulgaris and Beta maritima was assessed. The soil was a calcareous Xeric Torriorthent and the total metal levels were (mg kg−1): 2706 Zn, 3235 Pb, and 39 Cu. The treatments were: fresh cow manure, olive husk, and inorganic fertilizer as a control. Two successive crops (B. vulgaris and B. maritima) were grown on the treated and untreated plots. The soil was sampled before each planting and after each harvest over a 15‐mo period. Biomass C and N increased in all plots, especially in the organically amended ones. The ratio CO2–C/biomass C decreased in olive husk and manure‐treated plots, in comparison with the control, and also during the experiment, suggesting a beneficial effect of the organic amendments. In olive husk‐treated plots a significant increase in the ratio of biomass C/total organic carbon (TOC) with time was observed. This indicated a reduction of heavy metal stress on the microbial population. The amendments showed, in general, a beneficial effect on soil quality and fertility, while microbial biomass parameters were found to be useful indicators of the evolution of the remediation processes.
Remediation of Heavy Metal–Contaminated Forest Soil Using Recycled Organic Matter and Native Woody Plants
Authors: Helmisaari H.‐S. , Salemaa M. , Derome J. , Kiikkilä O. , Uhlig C. , Nieminen T. M.
Published: June 2007

The main aim of this study was to determine how the application of a mulch cover (a mixture of household biocompost and woodchips) onto heavy metal–polluted forest soil affects (i) long‐term survival and growth of planted dwarf shrubs and tree seedlings and (ii) natural revegetation. Native woody plants (Pinus sylvestris, Betula pubescens, Empetrum nigrum, and Arctostaphylos uva‐ursi) were planted in mulch pockets on mulch‐covered and uncovered plots in summer 1996 in a highly polluted Scots pine stand in southwest Finland. Spreading a mulch layer on the soil surface was essential for the recolonization of natural vegetation and increased dwarf shrub survival, partly through protection against drought. Despite initial mortality, transplant establishment was relatively successful during the following 10 yr. Tree species had higher survival rates, but the dwarf shrubs covered a larger area of the soil surface during the experiment. Especially E. nigrum and P. sylvestris proved to be suitable for revegetating heavy metal–polluted and degraded forests. Natural recolonization of pioneer species (e.g., Epilobium angustifolium, Taraxacum coll., and grasses) and tree seedlings (P. sylvestris, Betula sp., and Salix sp.) was strongly enhanced on the mulched plots, whereas there was no natural vegetation on the untreated plots. These results indicate that a heavy metal–polluted site can be ecologically remediated without having to remove the soil. Household compost and woodchips are low‐cost mulching materials that are suitable for restoring heavy metal–polluted soil.
Natural Alkalinity Generation in Neutral Lakes Affected by Acid Mine Drainage
Authors: Koschorreck Matthias , Tittel Jörg
Published: June 2007

Lakes in surface mining areas are often subject to continuous loads of acid mine drainage. The knowledge of internal alkalinity generation in a lake is necessary to predict if the lake will stay circumneutral or may acidify. The most important processes of alkalinity production in lakes are sulfate reduction, denitrification, and the burial of N in the sediment. By summarizing data from the literature, we present probable rates of these different processes in circumneutral mining lakes. The critical acidity load that can probably be compensated for by internal processes, is 5.09 mmol(−) m−2 d−1 in productive lakes and 0.50 mmol(−) m−2 d−1 in less productive lakes. Under the assumption that methanogenesis is inhibited by high sulfate concentrations, the highest probable acidity loads in such lakes are 6.85 mmol(−) m−2 d−1 and 1.06 mmol(−) m−2 d−1, respectively. Denitrification, sulfate reduction, and N burial contributed significantly to total alkalinity production. Sulfate reduction had the largest potential. However, existing models cannot predict alkalinity generation from sulfate concentrations alone because the long‐term stability of reduced S compounds in the sediment is crucial for a sustainable biological alkalinity generation. The larger acid‐neutralizing potential of higher trophic lakes is caused both by higher rates of microbial activity and by a greater stability of reduced reaction products in the sediment. The largest uncertainties in our knowledge with respect to the total alkalinity budget are related to microbial processes in sulfate‐rich freshwater lakes and the long‐term stability of reduced reaction products in the sediment.
Elevated Cadmium Concentrations in Potato Tubers Due to Irrigation with River Water Contaminated by Mining in Potosí, Bolivia
Authors: Oporto Carla , Vandecasteele Carlo , Smolders Erik
Published: June 2007

Risk of cadmium (Cd) in the human food chain in Cd‐contaminated areas is often limited by phytotoxicity from zinc (Zn) that is associated with the Cd contamination. A semiarid area, 60 km downstream of a tin mine in Bolivia, was surveyed where irrigation with Cd‐contaminated river water (65–240 μg Cd L−1) has increased median soil Cd to 20 mg kg−1 while median soil Zn was only about 260 mg kg−1. Cadmium concentrations in potato tubers increased from background values (0.05 mg kg−1 dry wt.) in soils irrigated with spring water to a median value of 1.2 mg kg−1 dry wt. in the affected area. Median concentration of Cd in soil solutions was 27 μg L−1 and exceeded the corresponding value of Zn almost twofold. Soil‐extractable chloride ranged from 40 to 1600 mg Cl− kg−1 and was positively correlated with soil total Cd. Increasing soil solution Cl− decreased the solid‐liquid distribution coefficient of Cd in soil. Soil total Cd explained 64% of the variation of tuber Cd concentration while only 3% of the variation was explained by soil extractable Cl− (n = 49). The estimated dietary Cd intake from potato consumption by the local population is about 100 μg d−1 which exceeds the WHO recommended total daily intake. It is concluded that the food chain risk of Cd in the irrigation water of the semiarid area is aggravated by the association with Cl− and, potentially, by the relatively large Cd/Zn ratio.
Multivariate statistical interpretation of laboratory clinical data
Authors: Papaioannou Agelos , Simeonov Vasili , Plageras Panagiotis , Dovriki Eleni , Spanos Thomas
Published: June 2007

Laboratory aids are extensively used in the diagnosis of diseases, in preventive medicine, and as management tools. Reference values of clinically healthy people serve as a guide to the clinician in evaluating biochemical parameters. Determination of 21 biochemical parameters of healthy persons using standard methods of analysis. Cluster analysis and principal components analysis were applied on the above 21 biochemical parameters data. The application of a typical classification approach as cluster analysis proved that four major groups of similarity between all 21 clinical parameters are formed, which correspond to the authors assumption of the existence of several summarizing pattern of clinical parameters such as “enzyme,” “major component excretion”, “general health state,” and “blood specific” pattern. These patterns appear also in the subsets obtained by separation of the general dataset into “male”, “female”, “young”, and “adult” healthy groups. The results obtained from principal components analysis have additionally proved the validity of a similar assumption. The intelligent data analysis on the clinical parameter dataset has shown that when a complex system is considered as a multivariate one, the information about the system substantially increases. All these results support an idea that probably a general health indicator could be constructed taking into account the existing classification groups in the list of clinical parameters.
Comparison of 2 methods of centesis of the bursa of thebiceps brachiitendon of horses
Authors: SCHUMACHER J. , LIVESEY L. , BRAWNER W. , TAINTOR J. , PINTO N.
Published: June 2007

Reasons for performing study: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation.

Objective: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted.

Methods: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS.

Results: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined.

Conclusions: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.
Equine laminitis: ultrastructural lesions detected 24–30 hours after induction with oligofructose
Authors: NOURIAN A. R. , BALDWIN G. I. , van EPS A. W. , POLLITT C. C.
Published: June 2007

Reasons for performing study: The pathology of equine laminitis has been well‐documented 48 h after dosing with oligofructose when clinical lameness and lamellar disintegration is well advanced. Further analysis of the earliest lesions, by collecting lamellar samples at the first sign of foot lameness after oligofructose dosing is required in order to increase understanding of the disease.

Objectives: To investigate lamellar epidermal hemidesmosome damage and basement membrane dysadhesion by transmission electron microscopy (TEM).

Methods: Eight clinically normal, mature Standardbred horses were divided randomly into 2 groups of 4. The treatment group were dosed with oligofructose (10 g/kg bwt) and subjected to euthanasia when shifting weight from one foot to other commenced and at the first sign of lameness during walking and turning. This occurred at 24 h in 3 horses and 30 h in one. The sham treatment control group were dosed with water and subjected to euthanasia after 48 h. Lamellar tissues of the front feet were harvested and processed for ultrastructural study using TEM.

Results: Examination by TEM showed excessive waviness of the basement membrane zone and pointed tips of some secondary epidermal lamellae, an ultrastructural lesion typical of laminitis. The average number of hemidesmosomes/μm of basement membrane was decreased and their distance from the centre of thelamina densaof the basement membrane was increased.

Conclusions: Laminitis lesions are detectable 24 h after oligofructose administration.

Potential relevance: Hindgut events occurring in the first 24 h after dosing have begun the destruction of the hoof lamellar interface. Prevention and treatment strategies should precede lameness if they are to be efficacious.
A survey of horse owners in Great Britain regarding horses in their care. Part 1: Horse demographic characteristics and management
Authors: HOTCHKISS J. W. , REID S. W. J. , CHRISTLEY R. M.
Published: June 2007

Reasons for performing study: Information is scarce as to how horses are kept and managed in the general horse population of Great Britain.

Objectives: To characterise the demographics of horses in Great Britain and assess their care (with particular reference to the respiratory system).

Methods: Horse owners were surveyed using a self‐administered postal questionnaire. These owners were selected randomly, following geographical stratification, using 2‐stage cluster sampling of veterinary practices and their clients.

Results: The overall response proportion to the survey was 68.2%. An investigation of nonresponse bias detected minimal differences between responders and nonresponders. A summary of the demographic characteristics, feeding and management of horses in a sample of the general population of Great Britain is presented.

Conclusions and potential relevance: Horses are kept under a great variety of conditions with some potentially exposed to high concentrations of organic dusts associated with stabling. This information is relevant to their health and welfare.
Equine idiopathic cheek teeth fractures. Part 1: Pathological studies on 35 fractured cheek teeth
Authors: DACRE I. , KEMPSON S. , DIXON P. M.
Published: June 2007

Reasons for performing study: There is little published information on the pathology of idiopathic fractures of cheek teeth (CT).

Objectives: To perform pathological examinations on equine CT with idiopathic fractures in order to establish fracture patterns and to gain information on their aetiopathogenesis.

Hypothesis: Gross and histological examination of CT with idiopathic fractures, including measurements of dentinal thickness, will provide information on fracture patterns, and on the duration and aetiopathogenesis of these fractures.

Methods: Of 35 CT with idiopathic fractures that were examined to determine their fracture patterns, 20 underwent gross, histological and ultrastructural examinations, including dentinal thickness measurements, with the latter compared to dentinal measurements of dental age and Triadan position matched control CT, to help determine the duration of any pre‐existing endodontic disease.

Results: The fracture planes involved the pulp chambers in 30 out of 35 CT examined, and ran through coalesced, carious infundibula in the other 5 (maxillary) CT. The maxillary CT, particularly the Triadan 09 position were preferentially affected. The most common fracture plane, which was termed a maxillary buccal slab fracture, occurred through the 2 lateral (1st and 2nd) pulp chambers of maxillary CT and usually involved only the clinical crown. Buccal slab fractures of mandibular CT (through 4th and 5th pulp chambers) and midline sagittal fractures through the infundibula (of maxillary CT) were the next most common fracture patterns. Reduced dentinal thickness (probably indicating prior pathological changes in the fractured CT) was present in 25% of fractured CT.

Conclusions: Most idiopathic equine CT fractures involve the pulp chambers, especially those on the buccal aspect of both upper and lower CT. No predisposition to fracture was found in the majority of affected CT that appeared to have a normal endodontic appearance prior to development of fractures through their pulp chambers. The remaining idiopathic CT fractures were caused by advanced infundibular caries.

Potential relevance: All CT with idiopathic fractures are all at risk of pulpar or even apical infection.
Verification of scintigraphic imaging for injury diagnosis in 264 horses with foot pain
Authors: DYSON S. , MURRAY R.
Published: June 2007

Reasons for performing study: Nuclear scintigraphy is commonly used as a diagnostic aid for foot pain, but there is limited information about different patterns of radiopharmaceutical uptake (RU) and their correlation with the results of other imaging modalities.

Objectives: To describe patterns of RU in horses with foot pain.

Materials and methods: Scintigraphic images of the feet of 264 horses with front foot pain were analysed subjectively and using region of interest analysis. Magnetic resonance images of all feet were analysed prospectively; the navicular bones were reassessed retrospectively and assigned a grade. A Spearman rank correlation test was used to test for a relationship between the scintigraphic grade of the navicular bone and magnetic resonance imaging (MRI) grade. Sensitivity and specificity of scintigraphy for detection of lesions in the deep digital flexor tendon (DDFT), the collateral ligaments (CL) of the distal interphalangeal (DIP) joint and the navicular bone were determined.

Results: Increased radiopharmaceutical uptake (IRU) was detected in: a) the navicular bone (36.6%); b) pool phase images in the DDFT (13.0%); and c) at the insertion of the DDFT on the distal phalanx (14.3%). There was focal IRU at the insertion of the medial or lateral CL of the DIP joint in 9.4% and 1.5% of limbs, respectively. There was IRU in the medial and lateral palmar processes in 7.6% and 3.4% of limbs, respectively. There was a significant positive correlation between the scintigraphy grade and total MRI grade for the navicular bone and no difference between either focal or diffuse IRU and total MRI grade. There was high specificity, but low sensitivity of scintigraphy for detection of MR lesions of the navicular bone, the DDFT and the CLs of the DIP joint.

Conclusions: Positive nuclear scintigraphic results are good predictors of injury or disease of the navicular bone, DDFT and CLs of the DIP joint. However, a negative scintigraphic result does not preclude significant injuries.

Clinical relevance: Nuclear scintigraphy is a useful tool in the investigation of foot lameness and may help to determine the significance of MR lesions, especially if >1 lesion is identified that may be contributing to lameness.
Use of concurrent scintigraphic and magnetic resonance imaging evaluation to improve understanding of the pathogenesis of injury of the podotrochlear apparatus
Authors: DYSON S. , MURRAY R.
Published: June 2007

Reasons for performing study: Use of physiological methods of diagnostic imaging could provide insight into the pathogenesis of foot pain in live horses.

Objectives: To describe patterns and intensity of increased radiopharmaceutical uptake (IRU) in the navicular bone, and relate this to distribution and types of signal intensity change in the navicular bone and to the presence or absence of lesions of the related soft tissue structures detected using MRI.

Materials and methods: Scintigraphic and MR images of 264 horses with unilateral or bilateral foot pain were analysed and graded. A Spearman rank correlation was used to test for relationships between scintigraphic grade of the navicular bone and MRI scores for each region of the bone. Chi‐square tests were used to test for associations between scintigraphy grade and presence of increased signal intensities, for differences in the proportion of focal and diffuse IRU between MRI grades, and for associations between an abnormal scintigraphic grade of the navicular bone and presence or absence of a lesion.

Results: There were significant positive correlations between scintigraphy grade and both maximum and total MRI grades for the navicular bone and between scintigraphy grade and the MRI grades for the flexor border, the distal border and medulla. However, there was no difference in the proportions of focal and diffuse IRU between navicular bone MRI grades, although diffuse IRU was relatively under‐represented inGrade 3navicular bones. There was no association between IRU in the navicular bone and MR lesions of either the DSIL origin or the CSL insertion, however there was an association between IRU in the navicular bone and combined lesions of the CSL, DSIL and navicular bursa. In limbs with a DDFT lesion, navicular bone scintigraphicGrades 2and3were over‐represented.

Conclusions and clinical relevance: Scintigraphy and MRI provide complementary information about the pathogenesis of lesions of the podotrochlear apparatus. Further understanding of these disease processes may eventually permit more targeted treatments.
Examining Teacher–Child Relationships and Achievement as Part of an Ecological Model of Development
Authors: O’Connor Erin , McCartney Kathleen
Published: June 2007

The purpose of the present study is to examine associations between quality of teacher–child relationships from preschool through third grade and children’s third-grade achievement using Phases I, II, and III data from the National Institute of Child Health and Human Development Study of Early Care and Education, a prospective study of 1,364 children from birth through sixth grade. There are three main findings. First, positive associations were found between quality of teacher–child relationships and achievement. Second, high quality teacher–child relationships buffered children from the negative effects of insecure or other maternal attachment on achievement. Third, the effect of quality of teacher–child relationships on achievement was mediated through child and teacher behaviors in the classroom. In sum, high quality teacher–child relationships fostered children’s achievement. Implications for educational practice are discussed.
Opening Up the Black Box: Literacy Instruction in Schools Participating in Three Comprehensive School Reform Programs
Authors: Correnti Richard , Rowan Brian
Published: June 2007

This study examines patterns of literacy instruction in schools adopting three of America’s most widely disseminated comprehensive school reform (CSR) programs (the Accelerated Schools Project, America’s Choice, and Success for All). Contrary to the view that educational innovations seldom affect teaching practices, the study found large differences in literacy instruction between teachers in America’s Choice schools and comparison schools and between teachers in Success for All schools and comparison schools. In contrast, no differences in literacy teaching practices were found between teachers in Accelerated Schools Project schools and comparison schools. On the basis of these findings and our knowledge of the implementation support strategies pursued by the CSR programs under study, we conclude that well-defined and well-specified instructional improvement programs that are strongly supported by on-site facilitators and local leaders who demand fidelity to program designs can produce large changes in teachers’ instructional practices.
Direct and split operator approaches with ELLAM for reactive transport equations
Authors: Younes Anis , Fahs Marwan
Published: June 2007

Numerical models for solving reactive solute transport in groundwater are often based on standard Eulerian methods, such as finite elements (FE). In this work, we combine the moving mesh Eulerian Lagrangian Localized Adjoint Method (ELLAM) with the direct substitution approach (DSA) and the sequential non‐iterative approach (SNIA) to accurately solve advection dominated problems including chemical reactions. Performances of ELLAM are evaluated in comparing SNIA_ELLAM and DSA_ELLAM to SNIA_FE and DSA_FE for (1) kinetic reactions with first‐order decay, Monod biodegradation, and interphase mass transfer problems and (2) equilibrium reactions with linear and nonlinear sorption problems. DSA_ELLAM (respectively SNIA_ELLAM) is shown to be more efficient and accurate than DSA_FE (respectively SNIA_FE). For the test cases with kinetics, SNIA_ELLAM is highly accurate and efficient. However, for equilibrium reactions, it induces numerical diffusion and DSA_ELLAM reveals the more efficient and accurate method. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Elektronische Aptasensoren
Authors: Willner Itamar , Zayats Maya
Published: June 2007

Die Selektion von Aptameren – Nucleinsäuren, die spezifisch niedermolekulare Substrate oder Proteine binden – mithilfe des SELEX‐Verfahrens (systematische Evolution von Liganden durch exponentielle Anreicherung) ermöglicht die Suche nach neuen spezifischen Erkennungsstrukturen. Vor allem die Anwendung von Aptameren als vielseitige Materialien für Biosensoren wurde in jüngster Zeit intensiv untersucht. In diesem Kurzaufsatz werden die aktuellen Fortschritte bei der Entwicklung elektronischer Sensoren auf Aptamerbasis (Aptasensoren) zusammengefasst, darunter elektrochemische, ionenselektive Feldeffekttransistor‐ und Quarzkristallmikrowaage‐Sensoren, und es werden Strategien zum Entwurf von signalverstärkenden und markierungsfreien Aptasensoren beschrieben.
Biodegradation of poly(butylene adipate‐co‐butylene terephthalate)/layered‐silicate nanocomposites
Authors: Someya Yoshihiro , Kondo Naoto , Shibata Mitsuhiro
Published: June 2007

The biodegradability of poly(butylene adipate‐co‐butylene terephthalate) (PBAT) and PBAT/starch composites with layered silicates prepared by melt intercalation was evaluated with aerobic biodegradability tests in soil and in an aqueous medium containing activated sludge. Nonmodified montmorillonite (MMT) and octadecylamine‐modified montmorillonite (ODA‐M), known to give a microcomposite and an intercalated nanocomposite for PBAT, respectively, were used as layered silicates. After they were buried in the soil for 8 months, the PBAT/MMT microcomposite exhibited a higher weight loss than the control PBAT, whereas the PBAT/ODA‐M nanocomposite showed a lower weight loss instead. Also, the biodegradability test in the aqueous medium, by determining the biochemical oxygen demand, showed that the addition of MMT and/or starch to PBAT promoted biodegradation, whereas the addition of ODA‐M did not. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Chemically attaching polyhydroxyethylmethacrylate brush on substrate surface, derivation, and the role in differential etching
Authors: Zhou Feng , Mu Zonggang , Wang Tingmei , Liu Zhilu , Yu Bo , Hao Jingcheng , Liu Weimin
Published: June 2007

This article reports the preparation and derivation of chemically tethered polyhydroxyethylmethacrylate (PHEMA) brush and its application in microfabrication. PHEMA brush was prepared by the surface‐initiated atomic transfer radical polymerization and derived by either organic reaction or sequence polymerization. The differential etching process was studied by atomic force microscope (AFM) and optical micrograph. PHEMA brush cannot prevent the underlying gold from dissolving in aqueous etchant KI/I2 solution. Differential etching of UV‐patterned PHEMA template resulted in metal (gold) rings. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007