bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication of core‐shell Fe3O4/polypyrrole and hollow polypyrrole microspheres
Authors: Lu Xiaofeng , Mao Hui , Zhang Wanjin 
Published: August 2008

AbstractA facile synthesis of highly‐regulated core‐shell Fe3O4/polypyrrole (PPy) microspheres is achieved using a surfactant directed chemical oxidation polymerization in aqueous solution. The thickness of the PPy layer can be tuned by the quantity of the pyrrole monomer. The formation of core‐shell Fe3O4/PPy microspheres lies on the static interactions between the SO3− group in sodium dodecyl sulphate molecules and Fe3O4 microspheres. Other surfactants such as cetyltrimethylammonium bromide and polyoxyethylene (10) isooctylcyclohexyl ether (Triton X‐100) directed polymerization cannot produce such highly‐regulated core‐shell Fe3O4/PPy microspheres. XPS spectra proved the core‐shell structure of the composite microspheres. XRD, FTIR, and UV–vis spectra are used to characterize the chemical structure of the composite microspheres. The electrical and magnetic properties are also investigated. Moreover, the obtained core‐shell Fe3O4/PPy microspheres can be converted to highly‐regulated hollow PPy microspheres by dissolving the Fe3O4 core with acid solution. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Ion beam induced charge (IBIC) irradiation damage study in synthetic single crystal diamond using 2.6 MeV protons
Authors: Lohstroh A. , Sellin P. J. , Gkoumas S. , Parkin J. , Veeramani P. , Prekas G. , Veale M. C. , Morse J. 
Published: August 2008

AbstractWe have studied the effects of irradiation induced damage on the detector response of a synthetic single crystal diamond radiation detector. Before introducing radiation damage, the spatial variation of the detector response was investigated using a highly focused 2.6 MeV proton beam. A very uniform response close to 100% charge collection efficiency (CCE) over the whole contact area was found at applied electric field strengths as low as 0.4 V μm–1. At lower biases, time dependent polarisation phenomena were observed and clearly reduced the average signal amplitude. Subsequently, the 2.6 MeV proton beam has been used to introduce radiation damage within selected areas. The ion beam induced charge imaging was repeated to probe the modified regions. Even at an applied electric field of 2.6 V μm–1, no signal above the analogue threshold of the system was observed in the areas which had received a dose larger then 5 × 1014 cm–2, whereas more than 90% CCE was reached in the area with 1012 protons cm–2. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical characterization of locally charged oxidized nanocrystalline diamond films by Kelvin force microscopy
Authors: Cˇermák J. , Kromka A. , Rezek B. 
Published: August 2008

AbstractA nanocrystalline diamond (NCD) thin film is deposited on a gold electrode and oxygen terminated by r.f. oxygen plasma. An atomic force microscope (AFM) is used to induce electrostatically charged micrometer‐sized areas on the diamond film by applying bias voltages in the range between –30 V and +30 V on the AFM tip during scanning in contact mode. Trapped charge was detected by Kelvin force microscopy showing a contact potential difference of 150 mV for both polarities. Decrease of surface potential by 20 mV in the positively charged area and by 90 mV in the negatively charged area is observed after 15 h under ambient conditions. Possible charge trapping mechanisms are discussed in terms of electret‐like or semiconductor‐like behavior of NCD thin films. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal conductivity of polycrystalline CVD diamond: effect of annealing‐induced transformations of defects and grain boundaries
Authors: Inyushkin A. V. , Taldenkov A. N. , Ralchenko V. G. , Vlasov I. I. , Konov V. I. , Khomich A. V. , Khmelnitskii R. A. , Trushin A. S. 
Published: August 2008

AbstractPolycrystalline CVD diamond has been annealed in vacuum at temperatures tan = 1550 °C–1690 °C to investigate an influence of modifications of grain boundaries (GB) and defects on thermal conductivity and optical properties of originally optical quality material. While the sample was converted by this heat treatment to “black diamond”, excitons still could be observed in cathodoluminescence spectra. Photoluminescence spectra revealed an aggregation of nitrogen (formation of H3 optical center) after annealing at 1690 °C. In‐plane thermal conductivity k (T) measured by a heated bar method in the temperature range T = 5–410 K shows a strong (up to 5 times) and monotonic decrease at T < 45 K upon annealing, while room temperature k (298 K) value remains almost constant (ca. 19.0 W/cm K) till tan = 1650 °C, rapidly degrading at higher tan. The experimental data on thermal conductivity are analyzed in the framework of full Callaway theory taking into account three‐phonon scattering processes, phonon scattering on point defects, sample boundaries, and GB. The proposed model reproduces well the observed k (T) behavior, the phonon scattering on the modified GB playing an important role. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Understanding the local and global impacts of model physics changes: an aerosol example
Authors: Rodwell Mark J. , Jung Thomas 
Published: August 2008

AbstractThis study demonstrates the use of a package of diagnostic techniques to understand the local and global responses to a given physics change within a general circulation model. Here, the package is applied to the case of a change in the aerosol climatology in the forecast model of the European Centre for Medium‐range Weather Forecasts. The largest difference between old and new climatologies is over the Sahara where, in particular, soil‐dust aerosol is reduced. Conventional diagnostics show that the change lead to improvements in local medium‐range forecast skill and reductions in seasonal‐mean errors throughout the globe. To study the local physics response, short‐range tendencies in weather forecasts are diagnosed. These tendencies are decomposed into the contributions from each physical process within the model. The resulting ‘initial tendency’ budget reveals how the local atmosphere responds to the aerosol change. The net tendencies also provide strong evidence to confirm that the new aerosol climatology is superior. Seasonal integrations demonstrate that the tropic‐wide response can be understood in terms of equatorial waves and their enhancement by diabatic processes. The so‐called ‘Rossby‐wave source’ is made applicable to general circulation models and used to understand how the tropical anomalies subsequently impact on the global circulation. The mean response in the extratropics is found to be a stationary wave field. Precipitation anomalies that are co‐located with extratropical divergent vorticity sources suggest the possibility for diabatic modification of the tropically forced Rossby‐wave response. Copyright © 2008 Royal Meteorological Society
Evaluation of irrigation canal networks to assess stream connectivity in a watershed
Authors: Colvin Michael E. , Moffitt Christine M. 
Published: August 2008

AbstractWe used digital data sets, aerial photos and direct field observations in a geographical information system to evaluate the stream habitat in an Idaho watershed affected by agriculture. We found that the scale of the digital data sets affected the outcome of the assessment due to the presence of dewatered stream channels in the drainage. We analysed the spatial configuration of irrigation canals in the watershed to determine if the contemporary stream network connectivity could be attributed to human‐ caused or to natural hydrological processes. Many irrigation canals were significantly longer than would have been expected if these canals were constructed to capture water from the closest portion of the abandoned stream channels. Our findings provide evidence that some of these tributary streams had reaches that were likely ephemeral or intermittent at the time of canal construction. Our approach for assessing stream and irrigation network connectivity in pastoral and agricultural lands should aid managers in prioritizing the effective and appropriate reconnection efforts. Published in 2008 by John Wiley & Sons, Ltd.
A reach‐scale remote sensing technique to relate wetland inundation to river flow
Authors: Frazier Paul , Page Ken 
Published: August 2008

AbstractKnowledge of the relationship between river flow and wetland inundation at a reach‐scale is important for effective flow management, particularly, for environmental outcomes. Historical remotely sensed data, such as Landsat TM, provide the potential to determine the relationship between flow and wetland inundation for extended river reaches. In this paper we apply, adapt and evaluate a technique using sets of before‐flood and after‐flood image pairs to relate river flow to wetland inundation on a 640 km reach of the mid‐Murrumbidgee River, Australia. Stratification of the complete reach into relatively uniform sub‐reaches on the basis of hydrology and geomorphology was undertaken as a key pre‐analysis step. Analysis of flood wave attenuation within each sub‐reach showed that flood peaks entering and leaving a reach were highly correlated. Therefore, we argue that a flood peak measured at a single gauge within the reach can be used to provide a reliable indication of the behaviour of similar sized floods within the reach. The remote sensing technique proved capable of producing a model relating wetland inundation thresholds to flood peak discharge for each sub‐reach within the extended river reach. Although the model simplifies the complex relationship between river flow and wetland inundation, reliable key wetland inundation flow thresholds were determined. Copyright © 2008 John Wiley & Sons, Ltd.
Impact of partial removal of the invasive macrophyte Lagarosiphon major (hydrocharitaceae) on invertebrates and fish
Authors: Bickel Tobias O. , Closs Gerard P. 
Published: August 2008

AbstractInvasive macrophyte species are a threat to native biodiversity and often grow to nuisance levels, therefore, making control options necessary. Macrophyte control can have pronounced impacts on littoral fish by reducing habitat heterogeneity and the loss of profitable (high density of invertebrates) foraging areas. Yet, there is little known about the impacts of macrophyte removal on invertebrates themselves. We conducted a macrophyte removal experiment, that is the cutting of channels into dense macrophyte beds, to investigate the impact of mechanical macrophyte control on invertebrate and fish communities in a littoral zone dominated by the invasive macrophyte Lagarosiphon major. The effect of macrophyte removal had only a temporary effect on macrophyte areal cover (4 months). Nevertheless, the treatment increased light penetration significantly. However, we could not detect any difference in epiphyton biomass. Invertebrate biomass increased in macrophyte stands 4 months after treatment and there was a shift in the invertebrate community composition. Mechanical control had no effect on invertebrate biodiversity. The higher invertebrate biomass did not translate into a higher fish density in the treated areas. The results of this study indicated that partial mechanical removal is a suitable option to control unwanted macrophyte stands. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison of methods for analysing salmon habitat rehabilitation designs for regulated rivers
Authors: Brown Rocko A. , Pasternack Gregory B. 
Published: August 2008

AbstractRiver restoration practices aiming to sustain wild salmonid populations have received considerable attention in the Unites States and abroad, as cumulative anthropogenic impacts have caused fish population declines. An accurate representation of local depth and velocity in designs of spatially complex riffle‐pool units is paramount for evaluating such practices, because these two variables constitute key instream habitat requirements and they can be used to predict channel stability. In this study, three models for predicting channel hydraulics—1D analytical, 1D numerical and 2D numerical—were compared for two theoretical spawning habitat rehabilitation (SHR) designs at two discharges to constrain the utility of these models for use in river restoration design evaluation. Hydraulic predictions from each method were used in the same physical habitat quality and sediment transport regime equations to determine how deviations propagated through those highly nonlinear functions to influence site assessments. The results showed that riffle‐pool hydraulics, sediment transport regime and physical habitat quality were very poorly estimated using the 1D analytical method. The 1D and 2D numerical models did capture characteristic longitudinal profiles in cross‐sectionally averaged variables. The deviation of both 1D approaches from the spatially distributed 2D model was found to be greatest at the low discharge for an oblique riffle crest with converging cross‐stream flow vectors. As decision making for river rehabilitation is dependent on methods used to evaluate designs, this analysis provides managers with an awareness of the limitations used in developing designs and recommendations using the tested methods. Copyright © 2008 John Wiley & Sons, Ltd.
Aussteifung von Gebäudehüllen durch eckgeklotzte Glasscheiben
Authors: Wellershoff Frank 
Published: August 2008

AbstractHinsichtlich seiner Festigkeit zeigt Glas eine große hnlichkeit zum Beton und kann ebenso wie dieser ca. 10 fach höhere Druckspannungen als Zugspannungen aufnehmen. Das Potential der hohen Druckfestigkeit des Glases wurde jedoch bislang nur in wenigen Sonderprojekten genutzt. Übliche Verglasungen in Gebäudehüllen werden ausschließlich durch Lasten beansprucht, die senkrecht zur Scheibenebene wirken und bemessungsrelevante Oberflächenzugspannungen hervorrufen. Die Möglichkeit einer gleichzeitigen Übertragung von Druckkräften in der Scheibenebene könnte genutzt werden, um die Gebäudehülle auszusteifen oder um ein seitliches Ausweichen von Pfosten und Riegeln zu verhindern.Für das hier betrachtete System wurden neue Eckklotzungsdetails konzipiert und getestet. Das Tragverhalten von quadratischen Glasscheiben unter kombinierten Belastungen in der Scheibenebene und senkrecht zur Scheibenebene wurde analysiert und Bemessungsmodelle entwickelt. Die Verzweigungslast von eckgeklotzten, monolithischen Scheiben unter diagonaler Druckkraft konnte mit der Energiemethode analytisch bestimmt werden.
Schweißen ermüdungsbeanspruchter Altstahlkonstruktionen – Untersuchungen zum Sprödbruchverhalten geschweißter Verbindungen aus Flussstahl
Authors: Lüddecke Falk , Mehdianpour Milad , Graße Wolfgang 
Published: August 2008

AbstractBeim Schweißen wird durch die induzierte Kerbschärfe und die Eigenspannungen die Gefahr eines Sprödbruchs erhöht. Aufgrund der verringerten Zähigkeitseigenschaften von alten Flussstählen im Vergleich zu heutigen Baustählen ist daher eine Bewertung der Sprödbruchgefahr von Flussstählen nach dem Schweißen erforderlich. Für eine Bewertung auf bruchmechanischem Niveau wird der Spannungsintensitätsfaktor auf der Beanspruchungsseite mit der Bruchzähigkeit auf der Widerstandsseite verglichen. Für einen Großteil der früher verbauten Bleche bis 11 mm Dicke kann gezeigt werden, dass kein Sprödbruch zu erwarten ist. Darüber hinaus werden für größere Blechdicken Daten aufbereitet, die auf Basis der tatsächlich vorliegenden Materialbeanspruchbarkeiten und rechnerisch ermittelten Beanspruchungen eine Bewertung ermöglichen.
Experimentelle Tragfähigkeitsüberprüfung von Plattenmaterial Hohlkammerpolycarbonat 16 mm
Authors: Jahnke Hartwig , Jordan Sandra , Klink Thomas 
Published: August 2008

AbstractUm die Vermietbarkeit von Geschosswohnungen zu verbessern, werden zunehmend Balkone an Wohnhäuser angebaut. Fenster werden dabei zu Balkontüren umgestaltet. Der oberste Balkon soll dabei stets ein Dach erhalten. Das Dach besteht aus Plattenmaterial Hohlkammerpolykarbonat 16 mm, aufgelegt auf Vierkantprofilen. Ein statischer Nachweis für die Auflagerung und Befestigung der Hohlkammerplatten in den Vierkantprofilen, im Gegensatz zu dem Plattenmaterial selbst, kann nicht geführt werden. Da seitens des Balkonherstellers gewünscht wird, die Balkone deutschlandweit aufstellen zu können, muss die zulässige Belastung des Balkondaches experimentell ermittelt werden. Abgeleitet aus der Bruchlast im Belastungsversuch werden mit einem Sicherheitsfaktor von γ = 2,0 sowohl die zulässige Schnee‐ als auch die Windlast errechnet.
Elevated synaptophysin I in the prefrontal cortex of human chronic alcoholics
Authors: Henriksson Richard , Kuzmin Alexander , Ökvist Anna , Harper Clive , Sheedy Donna , Garrick Therese , Yakovleva Tatjana , Bakalkin Georgy 
Published: August 2008

AbstractConvergent lines of evidence suggest potentiation of glutamatergic synapses after chronic ethanol exposure, and indicate that the presynaptic effect hereof is on modulators of synaptic strength rather than on executors of glutamate release. To address this hypothesis in the context of ethanol dependence in humans, we used semiquantitative immunoblotting to compare the immunoreactivities of synaptophysin I, syntaxin 1A, synaptosome‐associated protein 25, and vesicle‐associated membrane protein in the prefrontal and motor cortices between chronic alcoholics and control subjects. We found a region‐specific elevation in synaptophysin I immunoreactivity in the prefrontal cortex of alcoholics, but detected no significant differences between the groups in the immunoreactivities of the other three proteins. Our findings are consistent with an effect of repeated ethanol exposure on modulators of synaptic strength but not on executors of glutamate release, and suggest a role for synaptophysin I in the enduring neuroplasticity in the prefrontal cortical glutamate circuitry that is associated with ethanol dependence. Synapse 62:829–833, 2008. © 2008 Wiley‐Liss, Inc.
Multidimensional social control variables as predictors of drunkenness among French adolescents
Authors: Bègue Laurent , Roché Sebastian 
Published: August 2008

ABSTRACTBackgroundPrevious studies of the determinants of drunkenness among youth investigated the contribution of a limited range of variables measuring social control. For the first time in France, this study including 1295 participants aged 14–19 years aimed at assessing the relative contribution of a broad range of multidimensional variables relating to social control such as parental and school functioning, conventional and religious beliefs, and activity level, in a single model predicting self‐reported drunkenness episodes.MethodsA logistic regression model based on a survey involving nearly 50 measures selected at the first step was conducted using a backward elimination procedure to identify the significant predictors of drunken experience controlling for age, gender and SES among a sample of French adolescents.ResultsWe found a protective effect of attachment and commitment to institutions in drunkenness experience among youth. Previous findings on parental variables were confirmed with qualifications, whereas the effect of religion was limited. The negative role of sport practice and impulsivity was also emphasized for some participants.
Predicting adolescent suicidality: Comparing multiple informants and assessment techniques
Authors: Connor Jennifer , Rueter Martha 
Published: August 2008

AbstractAdolescent suicidality is a serious problem among American youth. Common risk factors for adolescent suicidality include depression and conduct problems but there is little agreement on the best means to assess these factors. We compared multiple informants (mothers, fathers, the adolescent and a sibling) and multiple assessment techniques using a sample of more than 460 families. Assessment techniques included paper–pencil instruments, observer ratings, and diagnostic interviews. Suicidality was assessed concurrently and two years after the risk assessment. Adolescent‐reported paper–pencil instruments and diagnostic interviews were strongly associated with concurrent and future suicidality. Parents' report of adolescent feelings and behaviors were also useful. Observed behaviors were not useful in assessing suicidality risk factors. Clinical recommendations include utilizing paper–pencil and diagnostic adolescent risk factor assessment and focusing on emotions.
Student engagement and its relationship with early high school dropout
Authors: Archambault Isabelle , Janosz Michel , Fallu Jean‐Sébastien , Pagani Linda S. 
Published: August 2008

AbstractAlthough the concept of school engagement figures prominently in most school dropout theories, there has been little empirical research conducted on its nature and course and, more importantly, the association with dropout. Information on the natural development of school engagement would greatly benefit those interested in preventing student alienation during adolescence. Using a longitudinal sample of 11,827 French‐Canadian high school students, we tested behavioral, affective, cognitive indices of engagement both separately and as a global construct. We then assessed their contribution as prospective predictors of school dropout using factor analysis and structural equation modeling. Global engagement reliably predicted school dropout. Among its three specific dimensions, only behavioral engagement made a significant contribution in the prediction equation. Our findings confirm the robustness of the overall multidimensional construct of school engagement, which reflects both cognitive and psychosocial characteristics, and underscore the importance attributed to basic participation and compliance issues in reliably estimating risk of not completing basic schooling during adolescence.
Early and middle adolescents' disclosure to parents about activities in different domains
Authors: Smetana Judith G. , Villalobos Myriam , Tasopoulos‐Chan Marina , Gettman Denise C. , Campione‐Barr Nicole 
Published: August 2008

AbstractDisclosure, disclosure strategies, and justifications for nondisclosure for prudential, peer, multifaceted, and personal acts were assessed using a sorting task with 118 lower‐middle class early and middle adolescents (Ms = 12.77 and 15.68 years). Adolescents were less involved in prudential than other behaviors, although prudential behavior was greater among middle than early adolescents; adolescents disclosed more about prudential and personal than multifaceted and peer behaviors. Nondisclosure was primarily due to concerns about parental disapproval (for prudential acts), claims that acts were personal or not harmful (for personal acts), and their mixture (for peer and multifaceted acts). When concerned about parental disapproval, older adolescents fully disclosed less (and lied somewhat more) than younger adolescents, whereas adolescents primarily avoided discussing the issue when they viewed acts as personal. Full disclosure was associated with better relationships with parents and less depressed mood; lying was associated with more parental behavioral control over personal issues and poorer relationships with fathers.