bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of water pulsing on individual performance and competitive hierarchies in plants
Authors: Novoplansky Ariel , Goldberg Deborah E. 
Published: February 2007

Abstract. In a glass house experiment, we investigated the effect of both the frequency of water pulses and the total amount of water supplied on individual performance in the absence and presence of neighbors. We used monocultures and all combinations of pairs of seedlings of three species of perennial grasses, characteristic of different points along a soil moisture gradient within a semi‐arid grassland in New Mexico, USA.In the absence of neighbors, higher total water or more frequent (but smaller) pulses significantly increased growth of all three species. The species with the fastest intrinsic growth rate, and from the most productive habitat, exhibited the largest increase in absolute and relative growth in response to higher total water quantity.Competitive effects were highly significant overall and there were significant hierarchies of competitive ability. Under frequent pulses, the fast‐growing species from the most productive environment was the best competitor in terms of both ability to suppress other plants and ability to tolerate the presence of neighbors. However, under infrequent pulses, the slowest growing species from the least productive environment became a much stronger competitor, again in terms of both suppression and tolerance of neighbors.While differences in total water availability had greater effects than differences in pulsing regime on individual plant performance in the absence of competition, pulsing regime had much stronger effects on relative competitive abilities and thus may be more likely to influence field distribution patterns.
Competition between heather and grasses on Scottish moorlands: Interacting effects of nutrient enrichment and grazing regime
Authors: Alonso I. , Hartley S.E. , Thurlow M. 
Published: February 2007

Abstract. Considerable losses and degradation of heathlands (in moorlands and lowlands) have been reported across Europe, with Calluna vulgaris (heather) being replaced by other species, often grasses. Increasing atmospheric nitrogen deposition and overgrazing have been suggested as the driving factors behind this change. This possibility was investigated in a study of the interacting effects of nutrient inputs and grazing on heather and three grass species (Nardus stricta, Deschampsia cespitosa and D. flexuosa) in the field, on a moorland in northeastern Scotland. In addition, the interacting effects of increasing nutrients and Calluna canopy height on N. stricta and D. cespitosa were studied using turves in an outdoor experimental area. In the field, fencing had a larger effect than fertilizer on the growth of all species, except for N. stricta, the species most unpalatable to herbivores. Fencing led to an increase in the height of the Calluna canopy, which may reduce light availability for the grasses. In the turf experiment, the height of the Calluna canopy affected the diameter of the grass tussocks and percentage of green matter (i.e. live leaf material), with plants under the more closed Calluna canopies being smaller.This study suggests that the slow‐growing, evergreen Calluna is a more effective competitor than the faster growing grasses when it has a tall, intact canopy, even at increased levels of nutrient supply. However, overgrazing promotes gap formation in the Calluna canopy, providing an opportunity for grasses to take advantage of increased nutrients. Thus the conservation of heather moorlands requires an understanding of the grazing level which allows Calluna to maintain sufficient canopy structure to outcompete grasses for light.
Source Attribution and the Utilization of Obsidian in the Maya Area
Authors: Moholy-Nagy Hattula 
Published: February 2007

AbstractAssignment by instrument of Maya obsidian artifacts to geological sources has demonstrated the presence of several sources and variations in their distribution over time and space. Of special interest is the minor, but long-standing, presence of green and gray obsidian from Central Mexico. More attributions of large, carefully selected samples are necessary to continue the considerable progress already achieved in understanding Maya obsidian procurement and use. However, assignment by visual means is not an appropriate method for the Maya area because of the range of optical characteristics exhibited by gray Guatemalan and Central Mexican obsidians, some of which are common to several geological sources. Moreover, the determination of obsidian sources must not be considered an end in itself. Combining source results with behavioral typology and archaeological data can further our understanding of obsidian procurement and use in past cultural context. Finally, it would be helpful if analysts reported trace element composition in a standardized manner, so that archaeologists can easily compare the results from different laboratories.
Local Elites and the Reformation of Late Intermediate Period Sociopolitical and Economic Organization in Nasca, Peru
Authors: Conlee Christina A. 
Published: February 2007

AbstractThe Late Intermediate Period (A.D. 1000–1476) was a time between empires in the Andes when many regional groups reorganized and gained power. In the Nasca drainage this period has often been misrepresented, in part due to a focus on earlier cultural developments that were considerably different. Recent research attempts to provide a clearer picture of this time period by investigating sociopolitical and economic organization, and in particular the nature of local elites. Regional settlement patterns reveal that during this period population in the drainage was at its height with increased aggregation at town-size settlements. Excavations at the small village site of Pajonal Alto have identified local elites through variations in architecture and material culture. Evidence from Pajonal Alto reveals that there was a reformation of society in the Late Intermediate Period and local elites were no longer primarily associated with ceremonial centers but instead were present at every level of the settlement hierarchy. Elites obtained and maintained power in a variety of ways including participation in the production of utilitarian items, exchange, feasting, and community/exclusive ritual. Instead of integration through communal ritual on a regional level during certain times of the year, integration was based on a large network of local elites who had power that was wielded on a day-to-day basis.
Indigenous Ware or Spanish Import? The Case of Indígena Ware and Approaches to Power in Colonial Mexico
Authors: Rodríguez-Alegría Enrique , Neff Hector , Glascock Michael D. 
Published: February 2007

AbstractFor the last two decades, archaeologists have believed that a ceramic type known as Indígena Ware was an imitation of European majolica, produced by colonial Nahuas in Mexico City for lower-class Spanish families. Ideas surrounding the production and consumption of Indígena Ware, as well as majolica in general, have been based on the concepts of Spanish domination and indigenous acculturation. These ideas emphasize European interests in displaying high-value imports to obtain distinction along racial and class lines, and fail to consider indigenous strategies for obtaining power through craft production and display. We begin by critically evaluating the stylistic, iconographic, and technical evidence archaeologists have used to suggest that Indígena Ware was an indigenous product. We present the results from neutron activation analysis of 250 ceramic sherds indicating that Indígena Ware forms its own compositional group, different from Aztec pottery and Spanish majolica, and suggest that Indígena Ware is most likely a Spanish import. The problems this ware presents for classification reveal the limitations of locating power exclusively in the hands of the Spanish and point to ways in which we could overcome this theoretical problem for the study of colonialism in Mexico.
Transcutaneous ultrasonographic evaluation of gastric distension with fluid in horses
Authors: Lores Marcos , Stryhn Henrik , McDuffee Laurie , Rose Patricia , Muirhead Tammy 
Published: February 2007

Abstract
Objective—To develop a transcutaneous ultrasonography (TUS) method for measuring the location of the stomach during various levels of fluid distension and evaluate any correlation between gastric fluid distension and stomach position.
Animals—6 adult horses.
Procedures—Known volumes of water were administered in 2 trials. In trial 1, the stomach was evaluated prior to and after the administration of 2, 4, and 6 L of water. In trial 2, the stomach was evaluated after administration of 6, 8, 10, and 12 L of water. The TUS was performed at the 7th through 16th left intercostal spaces (ICSs). For each volume of water, an image was captured at the most dorsal point in each ICS where the dorsolateral aspect of the stomach wall was viewed. The distance between this point and a horizontal line drawn on the skin at the level of the elbow joint was measured. The measurements at all ICSs were used to estimate the gastric wall height at ICS 12, which was subsequently evaluated for statistical association with volume administered.
Results—Significant correlation between the estimated height of the stomach wall at ICS 12 and the volume of fluid administered was detected. A regression equation to estimate gastric fluid volume when initial values for gastric wall height (cm) at ICS 12 and fluid volume (L) are known was developed.
Conclusions and Clinical Relevance—Results suggested that use of TUS for gastric fluid volume estimation is a potentially useful technique.
Evaluation of the repeatability of rhinomanometry and its use in assessing transnasal resistance and pressure in dogs
Authors: Wiestner Thomas S. , Koch Daniel A. , Nad Natascha , Balli Aaron , Roos Malgorzata , Weilenmann Richard , Michel Erika , Arnold Susanna 
Published: February 2007

Abstract
Objective—To evaluate a modified posterior rhinomanometric method for clinical application in dogs.
Animals—15 healthy Beagles and 8 Bulldogs (4 healthy and 4 with respiratory problems).
Procedures—Rhinomanometry was performed 3 times within a 15-minute period in anesthetized dogs.Transnasal pressure (PNA) and nasal resistance (RNA) were determined by use of artificial airflow (adjusted for body weight) for inspiration (PNAin and RNAin, respectively) and expiration (PNAout and RNAout). Procedures were repeated for the Beagles 7 days later.
Results—For the Beagles, mean ± SD of PNAin for both days (0.162 ± 0.042 kPa) was significantly lower than PNAout (0.183 ± 0.053 kPa). Similarly, RNAin (1.47 ± 0.41 kPa/[L/s]) was significantly lower than RNAout (1.64 ± 0.46 kPa/[L/s]). Pairwise comparison of values for PNA and RNA for the 2 days revealed no significant difference. Repeatability of the method (estimated as within-day variation) for RNA was ± 0.19 kPa/(L/s), whereas variation between the days was ± 0.36 kPa/(L/s) for RNAin and ± 0.44 kPa/(L/s) for RNAout. The 4 clinically normal Bulldogs had RNA values ranging from 1.69 to 3.48 kPa/(L/s), whereas in the 4 Bulldogs with respiratory problems, RNA ranged from 9.83 to 20.27 kPa/(L/s).
Conclusions and Clinical Relevance—RNA is inversely dependent on body size and nonlinearly associated with airflow. We propose that RNA in dogs should be determined for airflows standardized on the basis of body size. The PNA and RNA in Beagles can be measured with sufficient repeatability for clinical use and nasal obstructions are detectable.
Subtotal penile amputation and preputial urethrostomy in a dog
Authors: Pavletic Michael M. , O'Bell Susan A. 
Published: February 2007

Abstract
Case Description—A 6-year-old castrated male Shih Tzu was evaluated because of intermittent bleeding during urination.
Clinical Findings—Necrosis of the cranial portion of the penile shaft extended distally from the preputial fornix. Penile necrosis secondary to strangulation from paraphimosis was diagnosed.
Treatment and Outcome—A midline preputiotomy incision was used to expose the penile shaft; amputation was performed caudal to the preputial fornix. The terminal portion of the urethra was anastomosed to the preputial mucosa, which allowed the dog to urinate through the preputial orifice.
Clinical Relevance—Unlike the more conventional urethrostomy procedures performed in dogs, preputial urethrostomy eliminates the potential for local skin irritation during urination. Preputial urethrostomy is also easier to perform in those dogs in which penile amputation is required adjacent to the preputial fornix. A release incision cranial to the prepuce can be used to facilitate caudal displacement of the preputial mucosa, which facilitates urethral anastomosis to this structure. A midline preputiotomy incision provided excellent exposure of the penile shaft for this surgical procedure.
Comparative study of layered tetravalent metal phosphates containing various first-row divalent metals. Synthesis, crystalline structure
Authors: Szirtes László , Riess László , Megyeri János , Kuzmann Ernõ 
Published: February 2007

Abstract
The transition metal forms of α-zirconium-. titanium-, and hafnium phosphates were prepared by ion exchange method. Their structure was investigated by X-ray powder diffraction (XRPD) method. It was found that the transition metal containing phosphates have the same layered structure as the pristine tetravalent metal phosphates, except for the increase of interlayer distance from 7.6 Å to ∼9.5 Å. As a result of the incorporation of transition metals in the layers, the c-axis is increased from ∼15 Å to ∼20 Å (in the case of titanium phosphate to ∼25 Å). All other parameters (a, b and β °) are practically unchanged.
Voltammetric quantitation at the mercury electrode of the anticholinergic drug flavoxate hydrochloride in bulk and in a pharmaceutical formulation
Authors: Ghoneim M.M. , El-Attar M.A. , Razeq S.A. 
Published: February 2007

Abstract
Flavoxate hydrochloride, 2-piperidinoethyl 3-methyl-4-oxo-2-phenyl-4-H-chromene-8-carboxylate, is a smooth muscle antispasmodic. Its electrochemical behavior was studied at the mercury electrode in buffered solutions containing 30% (v/v) methanol using dc-polarography, differential-pulse polarography, cyclic voltammetry, and linear sweep-and square-wave adsorptive stripping voltammetry. Sensitive and precise procedures were developed for determination of bulk flavoxate hydrochloride and in the pharmaceutical formulation Genurin® S.F, without sample pretreatment or extraction. Limits of quantitation (LOQ) of 1 × 10−5, 5 × 10−6, 1 × 10−8 and 1 × 10−9 M flavoxate hydrochloride were achieved by dc-polarography, differential-pulse polarography, linear sweep and square-wave adsorptive stripping voltammetric, respectively.
A theoretical investigation on the isomerism and the NMR properties of thiosemicarbazones
Authors: Nuwan De Silva N. , Albu Titus 
Published: February 2007

Abstract
Hybrid density functional theory calculations at the mPW1PW91/6-31+G(d,p) level of theory have been used to investigate the optimized structures and other molecular properties of five different series of thiosemicarbazones. The investigated compounds were obtained from acenaphthenequinone, isatin and its derivatives, and alloxan. The focus of the study is the isomerism and the NMR characterization of these thiosemicarbazones. It was found that only one isomer is expected for thiosemicarbazones and methylthiosemicarbazones, while for dimethylthiosemicarbazones, two isomers are possible. All investigated thiosemicarbazones exhibit a hydrazinic proton that is highly deshielded and resonates far downfield in the proton NMR spectra. This proton is a part of a characteristic sixmembered ring, and its NMR properties are a result of its strong, intermolecular hydrogen bond. The relationships between the calculated 1H and 13C NMR chemical shifts and various geometric parameters are reported.
Highly Efficient Orange and Green Solid‐State Light‐Emitting Electrochemical Cells Based on Cationic IrIII Complexes with Enhanced Steric Hindrance
Authors: Su H.‐C. , Fang F.‐C. , Hwu T.‐Y. , Hsieh H.‐H. , Chen H.‐F. , Lee G.‐H. , Peng S.‐M. , Wong K.‐T. , Wu C.‐C. 
Published: February 2007

AbstractHighly efficient orange and green emission from single‐layered solid‐state light‐emitting electrochemical cells based on cationic transition‐metal complexes [Ir(ppy)2sb]PF6 and [Ir(dFppy)2sb]PF6 (where ppy is 2‐phenylpyridine, dFppy is 2‐(2,4‐difluorophenyl)pyridine, and sb is 4,5‐diaza‐9,9′‐spirobifluorene) is reported. Photoluminescence measurements show highly retained quantum yields for [Ir(ppy)2sb]PF6 and [Ir(dFppy)2 sb]PF6 in neat films (compared with quantum yields of these complexes dispersed in m‐bis(N‐carbazolyl)benzene films). The spiroconfigured sb ligands effectively enhance the steric hindrance of the complexes and reduce the self‐quenching effect. The devices that use single‐layered neat films of [Ir(ppy)2sb]PF6 and [Ir(dFppy)2sb]PF6 achieve high peak external quantum efficiencies and power efficiencies of 7.1 % and 22.6 lm W–1) at 2.5 V, and 7.1 % and 26.2 lm W–1 at 2.8 V, respectively. These efficiencies are among the highest reported for solid‐state light‐emitting electrochemical cells, and indicate that cationic transition‐metal complexes containing ligands with good steric hindrance are excellent candidates for highly efficient solid‐state electrochemical cells.
Formation of a Ground‐State Charge‐Transfer Complex in Polyfluorene//[6,6]‐Phenyl‐C61 Butyric Acid Methyl Ester (PCBM) Blend Films and Its Role in the Function of Polymer/PCBM Solar Cells
Authors: Benson‐Smith J. J. , Goris L. , Vandewal K. , Haenen K. , Manca J. V. , Vanderzande D. , Bradley D. D. C. , Nelson J. 
Published: February 2007

AbstractEvidence is presented for the formation of a weak ground‐state charge‐transfer complex in the blend films of poly[9,9‐dioctylfluorene‐co‐N‐(4‐methoxyphenyl)diphenylamine] polymer (TFMO) and [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM), using photothermal deflection spectroscopy (PDS) and photoluminescence (PL) spectroscopy. Comparison of this polymer blend with other polyfluorene polymer/PCBM blends shows that the appearance of this ground‐state charge‐transfer complex is correlated to the ionization potential of the polymer, but not to the optical gap of the polymer or the surface morphology of the blend film. Moreover, the polymer/PCBM blend films in which this charge‐transfer complex is observed also exhibit efficient photocurrent generation in photovoltaic devices, suggesting that the charge‐transfer complex may be involved in charge separation. Possible mechanisms for this charge‐transfer state formation are discussed as well as the significance of this finding to the understanding and optimization of polymer blend solar cells.
Replication and Coating of Silica Templates by Hydrothermal Carbonization
Authors: Titirici M.‐M. , Thomas A. , Antonietti M. 
Published: February 2007

AbstractHierarchical carbon materials with functional groups residing at the surface are prepared for the first time by using nanostructured silica materials as templates in combination with hydrothermal carbonization at mild temperatures (180 °C). Different carbon morphologies (e.g., macroporous casts, hollow spheres, carbon nanoparticles, and mesoporous microspheres) can be obtained by simply altering the polarity of the silica surface. The surface functionality and hydrophilicity of the resulting materials are assessed by Fourier transform IR spectroscopy, X‐ray photoelectron analysis, and water porosimetry. Raman spectroscopy and X‐ray diffraction measurements show that the materials are of the carbon‐black type, similar to charcoal.
Atomistic Study of a CaTiO3‐Based Mixed Conductor: Defects, Nanoscale Clusters, and Oxide‐Ion Migration
Authors: Mather G. C. , Islam M. S. , Figueiredo F. M. 
Published: February 2007

AbstractMixed oxide‐ion and electronic conductivity can be exploited in dense ceramic membranes for controlled oxygen separation as a means of producing pure oxygen or integrating with catalytic oxidation. Atomistic simulation has been used to probe the energetics of defects, dopant‐vacancy association, nanoscale cluster formation, and oxide‐ion transport in mixed‐conducting CaTiO3. The most favorable energetics for trivalent dopant substitution on the Ti site are found for Mn3+ and Sc3+. Dopant‐vacancy association is predicted for pair clusters and neutral trimers. Low binding energies are found for Sc3+ in accordance with the high oxide‐ion conductivity of Sc‐doped CaTiO3. The preferred location for Fe4+ is in a hexacoordinated site, which supports experimental evidence that Fe4+ promotes the termination of defect chains and increases disorder. A higher oxide‐ion migration energy for a vacancy mechanism is predicted along a pathway adjacent to an Fe3+ ion rather than Fe4+ and Ti4+, consistent with the higher observed activation energies for ionic transport in reduced CaTi(Fe)O3–δ.
Photochemical Formation of Au/Cu Bimetallic Nanoparticles with Different Shapes and Sizes in a Poly(vinyl alcohol) Film
Authors: Sakamoto M. , Tachikawa T. , Fujitsuka M. , Majima T. 
Published: February 2007

AbstractMetal nanoparticle (NP)–polymer nanocomposite thin films are attractive for applications in various devices. Since bimetallic NPs provide additional opportunities for tuning the physical properties of the NP components, the development of bimetallic NP nanocomposite thin films should lead to further enhancements of various applications. Au/Cu bimetallic NPs are fabricated in a poly(vinyl alcohol) (PVA) film using a photochemical process. Interestingly, different sizes and shapes of Au/Cu bimetallic NPs are formed in the PVA film, resulting in a uniquely patterned nanocomposite structure. It is determined that the different formation and growth mechanisms of NPs inside and outside the UV‐light irradiation spot leads to the differences in size and shape.
Highly Efficient Asymmetric Hydrogenation of Alkyl Aryl Ketones Catalyzed by Iridium Complexes with Chiral Planar Ferrocenyl Phosphino‐Thioether Ligands
Authors: Le Roux Erwan , Malacea Raluca , Manoury Eric , Poli Rinaldo , Gonsalvi Luca , Peruzzini Maurizio 
Published: February 2007

AbstractIridium complexes of planar‐chiral ferrocenyl phosphine‐thioether ligands were tested in the hydrogenation of simple ketones. Optimization of the conditions led to a highly active catalytic system with turnover numbers up to 915 and turnover frequencies up to ca. 250 h−1. Furthermore, very high enantioselectivities (up to >99 %) together with complete conversions were obtained for the asymmetric hydrogenation of various acetophenones at 10 °C.