bluuebunny/crossref_metadata_2025 huggingface dataset:
Violent Entertainment Pitched to Adolescents: An Analysis of PG-13 Films
Authors: Webb Theresa , Jenkins Lucille , Browne Nickolas , Afifi Abdelmonen A. , Kraus Jess
Published: June 2007

OBJECTIVE. The purpose of this study was to evaluate the violence content of the top-grossing PG-13 films of 1999 and 2000 to determine what percentage of it had potential for negative effects on young viewers and what percentage of it had potential for prosocial or beneficial effects.

METHODS. A large, multidimensional analytic instrument was designed for systematic coding of each act of violence and its contextualization by features that have been shown either to enhance or to protect against harmful effects that are associated with violent media exposure: perpetrators and victims of violence, motivation for violence, presence of weapons, degree of realism, and consequences of violence. Descriptive statistics by genre were performed for each film. An ordinal logistic regression model was used to examine the association between the seriousness of violence and weapons, motive, and genre.

RESULTS. In the sample of 77 PG-13 films, a total of 2251 violent actions were observed with roughly half (47%) of lethal magnitude. A total of 118 acts contained justified violence that were initiated by major characters and were extremely serious, and approximately two thirds of the films (49 [64%]) were rated PG-13 for reasons other than violence.

CONCLUSIONS. Violence permeated nearly 90% of the films in our study. Although only a small subset of this content contained violence that was associated with negative effects, only 1 film contained violence that was associated with protective or beneficial effects.
Continuity of Health Insurance Coverage Among Young Adults With Disabilities
Authors: Callahan S. Todd , Cooper William O.
Published: June 2007

OBJECTIVES. Although considered critical to facilitate the successful transition from pediatric to adult health care, the continuity of insurance coverage for young adults with disabilities as they make the transition to adulthood has not been well characterized. The purpose of this work was to compare the continuity of insurance coverage reported by a nationally representative sample of young adults 16 to 25 years old with and without disabilities during a consecutive 36-month period.

METHODS. We performed secondary analysis of data from the 2001 Survey of Income Program and Participation. Data for the survey were collected at 4-month intervals from February 2001 through January 2004 for 5170 young adults. Subjects with disabilities were those who reported limitations in activities of daily living or work, used assistive devices, and/or had learning disabilities, mental retardation, or other mental disorders. The primary outcome was uninsurance defined for each study month in which there was no coverage by private, public, or military programs. We present bivariate analyses of the months of uninsurance according to disability status using longitudinal weights and design-effect adjustments to account for the complex sample design.

RESULTS. The sample consisted of 599 subjects with and 4571 without reported disabilities, representing 3970000 and 30800000 young adults in the United States, respectively. At study entry, 22% of the young adults with disabilities were uninsured. During the 36-month follow-up period, 56% of the young adults with disability reported gaps in insurance coverage with a mean of 15 months of uninsurance. The proportion of uninsured subjects did not significantly differ by disability status.

CONCLUSIONS. The majority of young adults with disabilities reported gaps in insurance coverage, and many were uninsured for a substantial portion of the study period. As an increasing number of children with special health care needs make the transition to adulthood, improving the continuity of health insurance coverage for this population warrants specific attention.
Statistical Literacy for Readers ofPediatrics: A Moving Target
Authors: Hellems Martha A. , Gurka Matthew J. , Hayden Gregory F.
Published: June 2007

OBJECTIVE. Pediatric residents are expected to study research design and statistical methods to enable them to critically appraise the pediatric literature and apply the findings to patient care. However, it is not clear how best to teach these skills or even which statistical concepts are most important. An earlier study demonstrated that the statistical complexity of articles published in Pediatrics increased from 1952 to 1982. The goals of our study were to assess whether this trend has continued and to determine the statistical measures and procedures most commonly encountered in Pediatrics.

METHODS. We reviewed the print research articles published in Pediatrics, volume 115, 2005, and recorded the statistical measures and procedures reported in each article to determine how many articles used statistics or statistical procedures and what statistical procedures were encountered most commonly.

RESULTS. The proportion of articles that used any inferential statistics increased from 48% in 1982 to 89% in 2005. The mean number of inferential procedures per article increased from 2.5 in 1982 to 3.9 in 2005. The most commonly encountered statistical procedures or measures were descriptive statistics, tests of proportions, measures of risk, logistic regression, t tests, nonparametric tests, analysis of variance, multiple linear regression, sample size and power calculation, and tests of correlation. However, a reader who is familiar with only these concepts can understand the analyses used in only 47% of articles.

CONCLUSIONS. Our results confirm a trend toward the use of new and increasingly complex statistical techniques in Pediatrics. Educational efforts might most profitably focus on the principles underlying statistical analysis rather than on specific statistical tests. Authors, reviewers, and journal editors have a greater responsibility for ensuring that statistical procedures are used appropriately, as it may be increasingly unrealistic to expect readers to fully understand the statistical analyses used in journal articles.
Heelys and Street Gliders Injuries: A New Type of Pediatric Injury
Authors: Vioreanu Mihai , Sheehan Eoin , Glynn Aaron , Casidy Noelle , Stephens Michael , McCormack Damian
Published: June 2007

OBJECTIVES. Our goals were to highlight an increasing trend in orthopedic injuries in children as a result of “heeling” or “street gliding,” to describe injuries sustained by children using Heelys (HSL, Carrollton, TX) and Street Gliders (Glowgadgets Ltd, Bristol, United Kingdom), and to increase public awareness and prevent such injuries.

PATIENTS AND METHODS. We prospectively recorded the data of all roller shoes injuries referred to our department during the summer school holiday. Using a data-collection sheet, we recorded demographic data, type of injury, mechanism and place of injury, heeling or street-gliding experience, use of safety equipment, methods of treatment, and intention to continue heeling or street gliding after recovery from injury.

RESULTS. Over a 10-week period, 67 children suffered orthopedic injuries while using Heelys or Street Gliders. There were 56 girls and 11 boys with a mean age of 9.6 years. Upper limbs were the most common location of injury. Distal radius fractures were the most prevalent, followed by supracondylar fractures, elbow dislocations, and hand fractures. The majority of children suffered the injury while heeling or street gliding outdoors. Interestingly, 20% of the injuries happened while trying Heelys or Street Gliders for the first time, and 36% of the injuries occurred while learning (using 1–5 times) how to use them. None of the children used any sort of protective gear at the time of the injury. The majority of the injured children expressed their intention to continue heeling or street gliding after complete recovery from their injury.

CONCLUSIONS. Our study shows that the majority of children with injuries from heeling or street gliding are girls. We recommend close supervision of children using Heelys or Street Gliders during the steep learning curve and usage of protective gear at all times. These new types of injuries have a serious impact on child health and constitute a burden for the pediatric orthopedic service.
Compliance With Alarm Limits for Pulse Oximetry in Very Preterm Infants
Authors: Clucas Luisa , Doyle Lex W. , Dawson Jennifer , Donath Susan , Davis Peter G.
Published: June 2007

OBJECTIVE. The objective of this study was to determine the rate of compliance with hospital guidelines for alarm limits for pulse oximetry in preterm infants on oxygen therapy.

METHODS. All infants admitted to the nurseries at the Royal Women's Hospital, Melbourne, Australia, with gestational age <32 weeks or birth weight <1500 g between August 2005 and February 2006 were eligible for inclusion. Data on the alarm limits set for infants on oxygen therapy were collected prospectively. The target saturation range recommended in written hospital guidelines was 88% to 92%, with alarm limits set at 85% and 94%.

RESULTS. Data were prospectively collected for 144 subjects with mean (SD) gestational age 29.3 (2.4) weeks and birth weight 1226 (354) g; 1073 alarm limits were collected when infants were on oxygen. The lower alarm limit was set correctly 91.1% of the time. In contrast, the upper alarm limit was set correctly only 23.3% of the time: 76.5% of the time it was too high, and 23.8% of the time it was set at 100%. Infants with an upper alarm limit set correctly on a particular day had a significantly lower birth weight, gestational age, postmenstrual age, and postnatal age than infants who had the upper alarm limit set too high. Use of assisted ventilation, higher inspired oxygen concentrations, and more frequent changes in inspired oxygen concentration were all associated with improved odds of having an appropriately set upper alarm limit.

CONCLUSIONS. This study suggests that current guidelines regarding the upper pulse oximeter alarm limit for infants receiving oxygen might be commonly exceeded, although compliance might be better for infants at higher risk of adverse outcomes. However, there might be less variation from guidelines for the lower alarm limit.
The Success of an Immunization Information System in the Wake of Hurricane Katrina
Authors: Boom Julie A. , Dragsbaek Anna C. , Nelson Cynthia S.
Published: June 2007

Within days after Hurricane Katrina in September 2005, the Houston-Harris County Immunization Registry was connected to the Louisiana Immunization Network for Kids Statewide. This linkage provided immediate access to the immunization records of children who were forced to evacuate the New Orleans, Louisiana, area. One year later, >18900 immunization records have been found, representing an estimated cost savings of more than $1.6 million for vaccine alone and $3.04 million for vaccine plus administration fees. This experience demonstrated the vital and previously unrecognized functionality of immunization information systems in a public health emergency. Here we describe the Houston-Harris County Immunization Registry's experience after Hurricane Katrina in terms of maximizing the use of immunization information systems and the implications of this experience for patients, providers, and public health for future disaster-preparedness planning.
Quality of Primary Care and Subsequent Pediatric Emergency Department Utilization
Authors: Brousseau David C. , Hoffmann Raymond G. , Nattinger Ann B. , Flores Glenn , Zhang Yinghua , Gorelick Marc
Published: June 2007

OBJECTIVE. Our objective was to determine whether parent-reported, high-quality primary care was associated with decreased nonurgent pediatric emergency department utilization.

METHODS. A retrospective analysis of prospectively collected data for a cohort of children from the 2000–2001 and 2001–2002 Medical Expenditure Panel Survey panels was performed. Baseline parent-reported quality of primary care with respect to family-centeredness, timeliness, and realized access (a measure of the child's ability to receive necessary care and referrals) was assessed by using composite scores from the Consumer Assessment of Healthcare Providers and Systems survey. The primary outcomes were the numbers of subsequent nonurgent and urgent emergency department visits per child.

RESULTS. Of 8823 children included, 70.0% rated family-centeredness, 88.2% rated realized access, and 55.6% rated timeliness as high quality. After adjustment for demographic factors and health status, high-quality family-centeredness was associated with a 42% reduction in nonurgent emergency department visits for publicly insured children and a 49% reduction for children ≤2 years of age. Greater realized access was associated with a 44% reduction in nonurgent emergency department visits for children 3 to 11 years of age and a 56% reduction for children ≥12 years of age. Greater realized access was also associated with decreased nonurgent emergency department visits for publicly and privately insured children (37% and 35%, respectively). There was no significant association between timeliness and nonurgent emergency department utilization, nor was any quality-of-care domain associated with urgent emergency department utilization.

CONCLUSIONS. Parent-reported, high-quality family-centeredness and a high level of realized access to primary care were associated with decreased subsequent nonurgent emergency department visits for children. Parent reports of health care quality in these domains provide important complementary information on health care quality.
State Children's Health Insurance Program Achievements, Challenges, and Policy Recommendations
Authors:   Committee on Child Health Financing
Published: June 2007

This policy statement reviews the impressive progress of the State Children's Health Insurance Program since its enactment in 1997 and identifies outstanding challenges and state and federal policy recommendations. The American Academy of Pediatrics urges Congress to reauthorize SCHIP to strengthen its historic gains. The following set of recommended strategies for reauthorization pertain to funding, eligibility and enrollment, coverage, cost sharing, payment and provider-network capacity, and quality performance.
Study of the preparation and properties of CeO2single/multiwall hollow microspheres
Authors: Zhang Youjin , Cheng Tao , Hu Qixiu , Fang Zhiyong , Han Kaidong
Published: June 2007

Novel slight yellow CeO2single/multiwall hollow microspheres were synthesized by the hydrothermal method without any surfactant and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), and x-ray photoelectron spectra (XPS). The results showed that the products were CeO2single/multiwall hollow microspheres, the shells of which were composed of CeO2nanoparticles with a mean size of 70 nm. The effect of the preparation conditions, the reaction temperature, the reaction time, and the molar ratios of urea to Ce(NO3)3·6H2O on the morphology of the products, was investigated. The optimal preparation conditions are determined as follows: the reaction temperature of 230 °C, the reaction time of 6 to 10 h, and the molar ratios of urea to Ce(NO3)3·6H2O of 3:1 to 6:1. The formation mechanism of CeO2single/multiwall hollow microspheres was proposed. The ultraviolet-visible (UV-VIS) diffuse reflectance spectra of the samples were measured. The results showed that the absorption edges of the samples were red-shifted compared with that of bulk CeO2, and that the red-shift of the absorption edges and the yellow of the samples enhanced with increasing the yield of CeO2single/multiwall hollow microspheres. The catalytic activity and the recycling performance of the sample on CO oxidation were tested and theT100%(the temperature at which CO 100% conversion) was 230 °C in the first run and decreased by 270 and 205 °C compared with that of bulk CeO2and CeO2nanocrystal, respectively.
Effect of niobium on the oxidation behavior of TiAl
Authors: Lu Wei , Chen ChunLin , He LianLong , Xi YanJun , Wang FuHui
Published: June 2007

Two TiO2layers formed in TiAl oxidation for 50 h at 900 °C were studied using scanning transmission electron microscopy. The main efforts were placed on the investigation of the distribution of niobium. It was found that Nb enriched in TiO2grains of mixture layer but did not exist in the outer TiO2layer. High-resolution electron microscopy (HREM) Z-contrast image revealed that Nb substitute for Ti site leading to Nb enrichment in TiO2grains of the mixture layer. The formation mechanism of the two TiO2layers and the potential effect of Nb doping in the mixture layer were also discussed.
Homogeneous flow of bulk metallic glass composites with a high volume fraction of reinforcement
Authors: Fu X.L. , Li Y. , Schuh C.A.
Published: June 2007

We present a systematic study of homogeneous deformation in a La-based bulk metallic glass and two in situ composites based on the same glass. In contrast to prior investigations, which focused on relatively dilute composites, in this work the reinforcement volume percentages were more concentrated at 37% and 52%—near or above the percolation threshold (35–40%). Hot uniaxial compressive testing was conducted over a wide strain rate range from 10−2to 10−5s−1at a temperature near the glass transition. For such concentrated composites, the homogeneous deformation behavior appeared to be dominated by the properties of the reinforcement phase; in the present case the La reinforcements deformed by glide-controlled creep. Post-deformation analysis suggested that bulk metallic glass matrix composites were susceptible to microstructural evolution, which appeared to be enhanced by deformation, in contrast with a stress-free anneal. Consequently, unreinforced bulk metallic glass appeared to be more structurally stable than its composites during deformation near the glass transition.
Thermal characterization of GdSr2RuCu2Oy-based mixtures in the GdSr2RuO6–CuO pseudobinary system
Authors: Gombos Marcello , Ciancio Regina , Pace Sandro , Vecchione Antonio
Published: June 2007

Fundamental to investigating the coexistence of superconductivity and magnetic ordering in GdSr2RuCu2Oy(Gd1212) is the fabrication of macroscopic crystallographically oriented samples. To achieve this, we need to identify the conditions in which Gd1212 incongruent melting reaction, producing solid GdSr2RuO6(Gd1210) in Cu-rich liquid, dominates over decomposition due to RuO2sublimation. Only in these conditions is it possible, indeed, to grow oriented samples by any melting and resolidifying technique. Moreover, the optimal mixture of Gd1212 and its melting products has to be identified to perform melt-textured or flux-flow growth. By means of thermogravimetric and differential thermal analysis (TG–DTA) we analyzed, up to 1200 °C in air, several mixtures of Gd1212 with Gd1210 or CuO, performing a scan of the entire CuO–Gd1212–Gd1210 coexistence line of the Gd–Sr–Ru–Cu–O phase diagram. Gd1212 melting temperatures have shown a certain dependence on composition, decreasing about 30 °C for high Gd1210 content samples and about 20 °C for high CuO content samples with respect to pure Gd1212. A huge undercooling was observed for resolidification processes that were revealed to start at temperatures around 990 °C. Measurements proved that in this range of temperatures in air, no mass is lost at the end of each melting process, so that they are not affected by RuO2sublimation. A strong dependence on the atmosphere has also been observed for pure Gd1212, melting temperature decreasing by more than 80 °C from 100% O2atmosphere to He atmosphere (less than 10−2% O2). Measurements revealed that high O2partial pressures favor RuO2sublimation, whereas low oxygen atmospheres prevent resolidification.
Mg–Ti based materials for electrochemical hydrogen storage
Authors: Kalisvaart W.P. , Wondergem H.J. , Bakker F. , Notten P.H.L.
Published: June 2007

Results of the mechanical alloying of binary Mg–Ti and ternary Mg–Ti–Ni mixtures using two different process control agents are reported. Both high- and low-energy milling resulted in the formation of cubic compounds. When all starting reactants had disappeared, a mixture of two face-centered cubic (fcc) phases was formed with lattice constants around 4.40 and 4.25 Å. The electrochemical hydrogen storage capacity, 450 mAh/g for (Mg0.65Ti0.35)0.95Ni0.05, was about one-third that reported for Mg–Ti thin films. This suggested that only one of the two fcc phases was active at ambient conditions. Prolonged mechanical alloying of (Mg0.60Ti0.40)0.95Ni0.05resulted in full conversion of the material into one fcc-phase with a very small crystallite size, an intermediate lattice constant (4.33 Å), and a sharply decreased storage capacity.
Indentation behavior of polycrystalline copper under fatigue-peak overloading
Authors: Xu B.X. , Wang X.M. , Yue Z.F.
Published: June 2007

The indentation behavior of polycrystalline copper at room temperature was investigated with a flat cylindrical indenter applied to fatigue-peak overloading. The experimental results showed that fatigue-peak overloading can retard the indentation depth (d) propagation rate. After the period of overloading, thedpropagation rate arrived at a new steady-state value again. The greater the amplitude of the peak overloading, the more the number of cycles that were needed to remove the effect of overloading. The observations of indentation cross-sectional microstructures revealed that the mechanism ofdpropagation was the nucleation, formation, and propagation of cracks around the indentation. The experimental results and their interpretation implied that there were some similarities between the indentation fatigue-depth propagation and the conventional fatigue-crack propagation under fatigue-peak overloading.
Subfeature patterning of organic and inorganic materials using robotic assembly
Authors: Tafazzoli Afshin , Cheng Chao-Min , Pawashe Chytra , Sabo Emily K. , Trofin Lacramioara , Sitti Metin , LeDuc Philip R.
Published: June 2007

The ability to create small-scale material patterns using lithography has been limited by the feature sizes and assembly of the master stamping system. Developing a simple and robust robotically automated patterning technique for both organic and inorganic materials, which is able to be actively controlled down to scales smaller than the operating features, would enable new capabilities and directions in research. Here, a novel method is presented to form patterns of defined shape and distribution via automated assembly along with force-controlled microstamping. Robotic assembly based particle templates and pyramid structures were used to create controlled distributions of materials. Systems including quantum dots and biomolecules were patterned, demonstrating our ability to create repeatable geometries with size scales smaller than the master stamping system. These patterns were also utilized for constraining cell adhesion and spreading. This work has potential applications in diverse areas from building molecular circuits to probing biological pattern formation.
Biomimetic study of a polymeric composite material for joint repair applications
Authors: Ribeiro Rahul , Ganguly Poulomi , Darensbourg Donald , Usta Meitin , Ucisik A. Hikmet , Liang Hong
Published: June 2007

A longer lifespan is still being sought for biomaterials used for joint repair. We developed a new nanocomposite material of polytrimethylene carbonate (PTMC), hydroxyapatite (HAP), and multiwalled carbon nanotubes (MWNT) to mimic real cartilage. Experimental results were compared with those of natural cartilage and the conventional joint replacement material ultrahigh-molecular-weight polyethylene (UHMWPE). Friction experiments showed that our developed composite material had a coefficient of friction close to that of articular cartilage. Nanoindentation experiments indicated that the surface elastic behavior was similar to that of cartilage. The surface attraction forces on a silicon atomic force microscope tip were much higher for cartilage than those for the other two materials. These results hold promise for this artificial cartilage composite material’s performance in vivo, following further experimental investigations and chemical modifications.
Influence of alloying elements Ni and Nb on thermal stability and corrosion resistance of Cu-based bulk metallic glasses
Authors: Qin C.L. , Zhang W. , Asami K. , Kimura H. , Inoue A.
Published: June 2007

Bulk metallic glasses (BMGs) with critical diameters of 2.5–3 mm were synthesized in the (Cu0.6Zr0.3Ti0.1)100−x−yNiyNbxsystem by copper-mold casting. These alloys exhibit a large supercooled liquid region (ΔTx) of 40–60 K and a high reduced glass transition temperature (Tg/Tl) of 0.60–0.61, indicating high glass-forming ability and high thermal stability of the supercooled liquid. The corrosion rates in 1 N HCl and 3 mass% NaCl solutions significantly decrease by simultaneous alloying with Ni and Nb elements. The addition is also effective in raising the pitting potential in chloride solutions. The addition of Ni and Nb is favorable for the alloys in forming Zr-, Ti-, and Nb-enriched highly protective surface films in HCl and NaCl solutions.
The effects of a magnetic field on the crystallization of a fluorozirconate glass
Authors: Tucker Dennis S. , Lapointe Michael R. , Jia Zhiyong
Published: June 2007

An axial magnetic field of 0.1 T was applied to ZrF4–BaF2–LaF3–AlF3NaF fibers during heating to the glass crystallization temperature. Scanning electron microscopy and x-ray diffraction were used to identify crystal phases. It was shown that fibers exposed to the magnetic field did not crystallize, while fibers not exposed to the field did crystallize. A hypothesis based on magnetic work was proposed to explain the results, and was tested by measuring the magnetic susceptibilities of the glass and crystal.
Broadband near-infrared emission from Bi-doped aluminosilicate glasses
Authors: Zhou Shifeng , Feng Gaofeng , Bao Jiaxing , Yang Hucheng , Qiu Jianrong
Published: June 2007

Bi-doped sodium–potassium aluminosilicate glasses were synthesized and characterized. Broadband near-infrared (IR) emission covered the whole telecommunication wavelength region, with a maximum peak at about 1250 nm, a full width at half-maximum of about 370 nm, and a lifetime longer than 420 μs. The present glasses are potential materials for tunable lasers and optical amplifiers. The decrease of active Bi center concentration with the increase of Na2O content and the addition of CeO2are first reported here, and the IR emission center in sodium–potassium aluminosilicate glasses might be ascribed to low-valence-state bismuth, most probably, Bi+.
Prediction of formation of intermetallic compounds in diffusion couples
Authors: Liu Huashan , Wang Hang , Zhu Wenjun , Tao Xiaoma , Jin Zhanpeng
Published: June 2007

Formation of intermetallic compounds (IMCs) at the interface between two metals during soldering processing exerts much influence on the electrical and mechanical performance of integrate circuits (ICs). Considering both of the thermodynamic and kinetic factors (including nucleation and growth) on phase formation, a new model capable of predicting phase formation sequence at the interface between two metals with different structures has been proposed in this work. Application of this new model on the interfacial reactions between pure elemental pairs of metals such as Ni/Sn, Cu/In, Cu/Sn, and Co/Sn at different temperatures shows good agreement between predictions by this model and experimental observations.
Extracting the plastic properties of metal materials from microindentation tests: Experimental comparison of recently published methods
Authors: Guelorget Bruno , François Manuel , Liu Cheng , Lu Jian
Published: June 2007

Experimental verifications have been performed on three engineering metals to verify recent methods proposed for extracting stress–strain curves from indentation tests. Their sensitivity to data errors is evaluated. Finally, the factors that might cause the inaccuracy and instability of the proposed methods are discussed, providing information that can be useful for further improving these methods.
Microstructural evolution and magnetic properties of size-controlled nanocrystalline Ni in Ni(OH)2–ZrO2 composite
Authors: Nayak Bibhuti B. , Vitta Satish , Bahadur D.
Published: June 2007

Size-controlled nanocrystallites of Ni varying in size from 2 to 26 nm distributed in a nonmagnetic matrix of Ni(OH)2–ZrO2have been prepared by changing the reduction reaction time and by adding different concentrations of ZrOCl2solution to the initial reaction mixture. X-ray photoelectron spectroscopy indicates the presence of B2O3, Ni(OH)2, and ZrO2with Ni nanocrystals in the as-prepared composites. The room-temperature saturation magnetization and coercivity of the composites increases from ∼1.5 to 10 emu g−1and 100 to 200 Oe, respectively, when the ZrOCl2concentration in the reaction mixture increases to 0.10 M. The nanocrystals prepared without the addition of ZrOCl2exhibit a typical ferromagnetic response at 300 K, while that prepared with the addition of 0.10 M ZrOCl2shows a ferromagnetic response up to 400 K with higher saturation magnetization and coercivity.
Preferential photostructural modification of heteroleptic titanium alkoxides for molecular assembly
Authors: Musgraves J.D. , Potter B.G. , Sewell Robin M. , Boyle Timothy J.
Published: June 2007

The response of a mononuclear, heteroleptic titanium alkoxide [(OPy)2Ti(4MP)2, where OPy = pyridinecarbinol; NC5H4(CH2O) and 4MP = 4-mercaptophenol; OC6H4(SH)] to ultraviolet (UV) irradiation in dilute solution and in solid-state samples has been measured. Vibrational spectroscopy [Fourier transform infrared (FTIR) absorption and Raman scattering] was used to monitor changes in molecular structure upon exposure to 337.1- and 365-nm light. Assignment of spectral features to vibrational modes of the molecule was aided by a normal-mode analysis of the energy-minimized molecular structure within a density-functional theory framework. Photoinduced decreases in peak areas were observed in both FTIR spectra of the precursor solutions and Raman data collected from solution-cast films of the precursor material. These changes were associated with vibrational modes localized at the 4MP ligands. Conversely, no significant modification of vibrational structure associated with the OPy moiety was observed under the excitation conditions examined. In a related study, thin films of the precursor were cast, sampled, and irradiated with UV light in scintillation vials under hydrated air (40% relative humidity) and dry Ar to evaluate the influence of local atmospheric composition on the photoresponse. An increase in the magnitude of photoinduced vibrational changes was observed in the moist-air environment, again associated primarily with the 4MP ligand. The results support an interpretation of these structural changes in terms of a preferential enhancement of hydrolysis at the 4MP site under these conditions. These findings are discussed in the context of an optically driven molecular assembly strategy based on the photoinitiation of intermolecular bonding at selected sites about the metal center.
Morphology and molecular orientation of thin-film bis(triisopropylsilylethynyl) pentacene
Authors: Chen Jihua , Martin David C. , Anthony John E.
Published: June 2007

As a modification to the insoluble and herringbone-structured pentacene, bis(triisopropylsilylethynyl) (TIPS) pentacene has two bulky side groups, leading to good solubility in common organic solvents and regular π–π stacking arrangements in the crystalline state. Solution processing of TIPS–pentacene thin films was investigated as a function of various process parameters in this work. Electron diffraction results suggested that TIPS–pentacene molecules tended to align with the acene unit edge on to the substrate, touching down with their bulky side groups. In a TIPS–pentacene polycrystalline film, the long axis of individual crystallite is [2 1 0], while the shorter axis is [1 ¯20]. High-resolution electron microscopy was used to study the local crystal structure and characteristic defects of TIPS–pentacene thin films. Due to the nonaromatic side groups, TIPS–pentacene was found to be significantly more sensitive to the electron beam (critical dose Jc= 0.05 C/cm2at 300 kV) than pentacene itself (Jc= 0.2 C/cm2at 100 kV).
Sol-gel derived Nd1/3La1/3Ca1/3MnO3: Phase evolution and preparation of films and nanopowders
Authors: Pohl A. , Westin G.
Published: June 2007

An all-alkoxide sol-gel route to the formation of Nd1/3La1/3Ca1/3MnO3thin films and powders has been developed. The microstructural evolution on heat treatment of the gel to yield the perovskite oxide was monitored by means of thermogravimetric analysis-differential scanning calorimetry, powder x-ray diffraction (XRD), Fourier transform infrared spectroscopy, and transmission electron microscopy (TEM)-energy dispersive spectroscopy (EDS). It was found that the amorphous gel consists of hydrated oxo-carbonate without organic residues, and on heating it decomposes in several steps, finally forming single-phase perovskite at 680 °C. Further heating results in only slight changes in the cell parameters and crystal growth. Films were prepared by spin coating, followed by heat treatment in air to a temperature of 800 °C, and studied by scanning electron microscopy, TEM-EDS, and XRD. Films on Al2O3were more porous, while films on Pt–TiO2–SiO2–Si were rather dense and consisted of areas with different crystal orientations.
Synthesis of perfect silver nanocubes by a simple polyol process
Authors: Zhu Jiejun , Kan Caixia , Zhu Xiaoguang , Wan Jian-guo , Han Min , Zhao Yue , Wang Baolin , Wang Guanghou
Published: June 2007

In this work, we report on silver nanocubes with perfect shape prepared by a simple poly(vinyl pyrrolidone)-directed polyol synthesis process. The effects of poly(vinyl pyrrolidone)/AgNO3ratio Rand reaction temperature Ton the morphology and size of the products were investigated. Ag nanocubes with an average edge length of 230 nm were obtained successfully with sharp edges and corners under a precise synthesis condition of R= 1 and T= 150 °C. The optical properties of Ag nanocubes show an attractive plasma resonance red-shift with size in a wide spectra region. The growth mechanism of the Ag nanocubes is proposed to be thermodynamically and kinetically controlled.
High-energy grinding of FeMo powders
Authors: D’Incau M. , Leoni M. , Scardi P.
Published: June 2007

Iron-molybdenum powders ground in a planetary ball mill under different operating conditions were studied by x-ray diffraction line profile analysis using a recently developed whole powder pattern modeling approach. The evolution of the microstructure, expressed in terms of size distribution of coherent scattering domains, average dislocation density, and edge/screw character, shows the importance of the main process parameters: the ratio between jar and main disk rotation speeds, and ball milling time. A characteristic three-stage process is observed, with work hardening followed by particle flattening/bending before nanocrystalline grains form by a fragmentation process triggered by localized deformation. The relationship between lattice defect density and domain size suggests a progressive transition between statistically stored to geometrically necessary dislocations, with the latter mostly present as excess dislocations at the nanodomain boundary.
New GABAergic Interneurons Supported by Myelin-Specific T Cells Are Formed in Intact Adult Spinal Cord
Authors: Shechter Ravid , Ziv Yaniv , Schwartz Michal
Published: June 2007

Neural stem/progenitor cells are known to exist in the intact spinal cord, but the presence of newly formed neurons during adulthood has not been documented there to date. Here, we report the appearance of newly formed neurons under normal physiological conditions. These neurons are immature, express a GABAergic phenotype, and are primarily located in the dorsal part of the spinal cord. This localization appeared to be mediated by stromal-derived factor-1/CXC-chemokine receptor-4 signaling in the dorsal region. The extent of spinal cord neurogenesis was found to be greatly influenced by immune system integrity and in particular by myelin-specific T cells. These observations provide evidence for in vivo spinal cord neurogenesis under nonpathological conditions and introduce novel mechanisms regulating adult spinal cord plasticity.

Disclosure of potential conflicts of interest is found at the end of this article.
UB 30/274 Daer Viaduct replacement
Authors: Bell G. , Anderson B. , Rocke R.
Published: June 2007

The Saltire Society Design Commendation for the New Daer Viaduct reads ‘It will become the benchmark to which other similar schemes are prepared'. A two-span bridge carrying the West Coast main line over the River Clyde was replaced by a single river span. All construction of the new substructure and superstructure and jacking of the superstructure into its permanent position was carried out below the existing bridge with no disruptive track possession. Only one 42 h possession was utilised to remove the old superstructure and the original central pier and to install minor precast infill units. The superstructure comprised two steel edge through girders supporting a transverse steel composite deck. The edge girders were aligned to pass the ends of the original central pier. When the superstructure was jacked up, the concrete robust kerb and edge girders moved up outboard of the original bridge edge girders. Thus, prior to the possession, the superstructure had all been built except for the portion occupied by the original pier. Following removal of the pier, this portion was completed with a precast concrete unit.
Design and construction of the Metrolink Finback Bridge
Authors: Jones S. W. , Wrigley R. G.
Published: June 2007

The Manchester to Oldham line of the proposed Metrolink Phase 3 passes through the new Central Park business park utilising the existing track bed of a disused and dismantled heavy rail route. To the east of Thorp Road Bridge the new Metrolink route crosses the existing four tracks of the Manchester to Leeds Trans-Pennine railway. A post-tensioned concrete finback bridge has been provided to carry the new twin Metrolink tracks over the existing heavy rail route. In order to minimise disruption to the operational railway, the Finback Bridge was constructed in a position alongside and roughly parallel to the existing railway. Once the construction was substantially complete, the 6250 t bridge was rotated in plan through 21° to its final position during a weekend possession. The site constraints resulted in a reverse-curved horizontal alignment with the consequential requirement to cater for significant torsion in the design of the deck. The deck solution was a box section finback bridge with varying fin height and fin wall thickness. The bottom slab of the box was extended to cantilever outside the central fin to support the Metrolink tracks. The superstructure incorporates two types of post-tensioning; internal bonded tendons in the deck slab of the main span and external unbonded tendons located inside the fin.
Field testing of a 30-year-old composite Preflex railway bridge
Authors: Staquet S. , Kalogiannakis G. , Detandt H. , Van Hemelrijck D. , Espion B.
Published: June 2007

Within the framework of the French National Research Project MIKTI dealing with ‘composite steel-concrete footbridges and bridges for tomorrow', a loading test was performed in Belgium on a railway bridge deck consisting of simply supported composite ‘Preflex’ beams. The bridge was 30 years old at the time of the test so the time-dependent stress redistribution between the steel of the girders and the concrete was almost stabilised. The bridge deck was loaded progressively by two heavy diesel-electric locomotives. A 4 m long zone situated at the mid-span of the deck was instrumented and monitored during the loading test. The following measurements were taken: the mid-span deflection; the slopes in five locations; the length variations of 16 extensometers of 250 mm length situated near the bottom fibre of the beam and acoustic emission. All of the measurements showed that the behaviour of the bridge deck under the test load was linear elastic, the concrete was not cracked before the test and no cracking appeared in the concrete during the test. The concrete part of the cross-section fully contributed to the stiffness of the beam, confirming the excellent long-term behaviour of this kind of railway bridge, even after a very large number of live load-cycles applied on them during more than 30 years of service. These observations are in very good agreement with the values of stresses computed by a step-by-step method, applying the principle of superposition of linear viscoelasticity for modelling the time-dependent stress redistribution in these composite beams.
Monitoring of the Flat‐Tailed Horned Lizard With Methods Incorporating Detection Probability
Authors: GRANT TYLER J. , DOHERTY PAUL F.
Published: June 2007

Abstract:Difficulty in monitoring the flat‐tailed horned lizard (Phrynosoma mcallii) has led to controversy over its conservation status. The difficulty in detecting this species has discouraged large‐scale estimates of abundance and led to uncertainty over whether the species exists in population sizes of sufficient size for long‐term persistence. We incorporated detection probability into monitoring of this species using closed mark—recapture and distance‐sampling methods. Density estimation from mark—recapture abundance estimates was improved using an estimate of the proportion of time lizards were on the plot. We estimated the probability of detection on the line for distance sampling and adjusted density estimates accordingly. We estimated the populations of the Yuha Basin Management Area in 2002 and the East Mesa Management Area, Imperial County, California, USA, in 2003 to be 25,514 (95% CI 14,444‐38,970) and 42,619 (95% CI 23,161‐67,639), respectively. Two estimates of detection probability on the line in distance sampling by different methods were 0.45 and 0.65. Density estimates derived from distance analyses for 3 East Mesa Management Area plots and the Yuha Basin Management Area were 1.55 per ha (95% CI 0.64‐3.76) and 0.41 per ha (95% CI 0.22‐0.7), respectively. These are the first large‐scale estimates of abundance and density forP. mcallii.
Avian Community Structure Along a Mountain Big Sagebrush Successional Gradient
Authors: REINKENSMEYER DANIEL P. , MILLER RICHARD F. , ANTHONY ROBERT G. , MARR VERN E.
Published: June 2007

Abstract: We compared vegetative structure and bird communities among 4 successional states in central Oregon representing a continuum from 1) postburn grassland, 2) mountain big sagebrush—Idaho fescue (Artemisia tridentatA—Festuca idahoensis) shrub—steppe, 3) sagebrush—steppe—juniper (Juniperus occidentalis), to 4) old‐growth western juniper. Species richness, evenness, and diversity of bird communities were highest in old‐growth and mid‐successional juniper (22.9 species/transect and 23.6 species/transect, respectively) but lowest in the grasslands (17.6 species/transect). Bird species diversity was positively correlated with physiognomic cover diversity (r = 0.74, P = 0.001). Density of breeding birds was greatest in old‐growth juniper (6.6 birds/ha) and lowest in postburn grasslands (3.6 birds/ha) but similar in shrub—steppe and sagebrush—steppe—juniper (6.0 birds/ha and 5.5 birds/ha, respectively). Old‐growth juniper had the highest total densities of both tree and cavity nesters. Mountain chickadees (Parus gambeli), Cassin's finches (Carpodacus cassinii), chipping sparrows (Spizella passerina), brown‐headed cowbirds (Molothrus ater), mountain bluebirds (Sialia currucoides), dark‐eyed juncos (Junco hyemalis), Empidonax flycatchers, ash‐throated flycatchers (Myiarchus cinerascens), and northern flickers (Colaptes auratus) were more abundant in cover types dominated by junipers. Vesper sparrows (Pooecetes gramineus), western meadowlarks (Sturnella neglecta), green‐tailed towhees (Pipilo chlorurus), and horned larks (Eremophila alpestris) were associated with grassland communities. Brewer's sparrows (Spizella breweri), sage sparrows (Amphispiza belli), sage thrashers (Oreoscoptes montanus), and horned larks (Eremophila alpestris) were most abundant in sagebrush cover types. Management strategies should restore or maintain the desired proportions of the different successional states to maintain populations of grassland and sagebrush birds while providing habitat for tree and cavity nesting species.
Dynamics of Pneumonia in a Bighorn Sheep Metapopulation
Authors: CASSIRER E. FRANCES , SINCLAIR A. R. E.
Published: June 2007

Abstract: We investigated the dynamics of 8 populations of a bighorn sheep (Ovis canadensis) metapopulation in Hells Canyon, USA from 1997 to 2003. Pneumonia was the most common cause (43%) of adult mortality and the primary factor limiting population growth. Cougar (Puma concolor) predation was the second most‐frequent source (27%) of adult mortality but did not reduce the rate of population growth significantly. Most pneumonia‐caused mortality occurred in fall and early winter and most cougar predation occurred in late winter and early spring. Average annual survival of adult males (0.84) was lower than females (0.91). Pneumonia was the most common known cause of lamb mortality (86%), and pneumonia‐related mortality was detected whenever summer lamb survival was <50%. Pneumonia‐caused mortality rates in lambs were high from 21 days to 91 days of age and peaked at 42 days to 70 days. Summer pneumonia epizootics in lambs were independent of pneumonia‐caused mortality in adults. Pneumonia‐caused mortality occurred at the population level and was not synchronized geographically or temporally among populations. Although catastrophic all‐age pneumonia‐epizootics have previously been described in bighorn sheep, we found that chronic, although sporadic, pneumonia‐caused mortality in adults and lambs can also have important effects on the dynamics of bighorn sheep populations.
Estimating and Correcting for Bias in Population Assessments of Sooty Shearwaters
Authors: MCKECHNIE S. , FLETCHER D. , MOLLER H. , SCOTT D. S. , NEWMAN J. , BRAGG C.
Published: June 2007

Abstract: We investigated the precision and accuracy of an infrared burrowscope for detecting sooty shearwater (Pufffinus griseus) chicks at 13 plots from 3 islands in southern New Zealand in 2003. We partially excavated burrows systems to reveal the entire burrow contents after 2 teams of observers had prospected all burrow entrances. Accuracy was similar between islands and observer teams at approximately 85%. The majority of the inaccuracy stemmed from failure to detect some chicks. Logistic regression modeling identified 4 burrow characteristics occurring between the entrance and the nest‐site that influenced detection of burrow occupants. Detection was lower at nest‐sites further from burrow entrances, in burrows with a high rate of burrow division, and in burrows with a high level of curvature. There was a positive relationship between the interaction of rate of division and curvature and detection of chicks. Distance from the burrow entrance was the only parameter that could be reliably used as a predictor of detection rate, so a reduced model containing only this variable was constructed to correct for burrowscope bias. The correction factor performed well on The Snares and Bench Island where predicted bias was very similar to observed levels (within 5%), but bias was overestimated on Putauhinu by up to 19.1%. Consistent bias, lack of damage to burrows from excavation, and the successful application of a correction factor all indicate the value of further testing burrowscope accuracy on other burrow‐nesting seabird species.