bluuebunny/crossref_metadata_2025 huggingface dataset:
Greenlight-Laservaporisation oder konventionelle Elektroresektion der Prostata zur Behandlung der symptomatischen Prostatahyperplasie – David gegen Goliath?
Authors: Bachmann  , Ruszat
Published: January 2007

Die Elektroresektion der Prostata (TURP) gilt als «Goldstandard» bei der operativen Therapie der benignen Prostatahyperplasie (BPH). Trotz technischer Neuerungen bleibt die TURP ein potenziell komplikationsträchtiges Operationsverfahren. Während des letzten Jahrzehnts wurden zahlreiche neue Laserverfahren für die operative Therapie der BPH vorgestellt. Der wesentliche Vorteil der meisten Laserverfahren sind die durchwegs guten hämostatischen Eigenschaften, die ein fast blutfreies und für den Patienten sicheres Operieren ermöglichen. Jedoch weisen v.a. nicht-ablative Laserverfahren durch die notwendige postoperative Langzeitkatheterisierung eine postoperativ störende Dysurie, das verlängerte Ausscheiden von nekrotischem Material (sloughing) sowie eine erhöhte Reoperationsrate eindeutig Nachteile gegenüber der herkömmlichen TURP auf. Bei der Greenlight-Laservaporisation der Prostata handelt es sich um ein neues viel versprechendes Operationsverfahren für Patienten mit symptomatischer benigner Prostatahyperplasie. Infolge der Kombination von guten ablativen und exzellenten hämostyptischen Eigenschaften stellt dieses Operationsverfahren zudem eine sichere Option für ältere Patienten, bei denen die TURP zu gefährlich wäre, oder für sog. Hochrisikopatienten dar, bei denen die Notwendigkeit einer oralen Antikoagulation besteht.
Der Einfluss von Arbeitsbedingungen und Haushaltskontext auf krankheitsbedingte Fehlzeiten
Authors: Beblo Miriam , Ortlieb Renate
Published: January 2007

Zusammenfassung. In diesem Beitrag analysieren wir den Einfluss von Arbeitsbedingungen und Haushaltskontext auf krankheitsbedingte Fehlzeiten für Frauen und Männer. Damit sollen Unzulänglichkeiten einer bisher diesen Bereich dominierenden zweigeteilten Forschungsperspektive - mit Fokus auf der Arbeitssphäre für Männer und Fokus auf dem privaten Umfeld für Frauen - überwunden werden. Die empirische Analyse basiert auf Daten des Sozio-ökonomischen Panels. Die Ergebnisse einer Ordered-Probit-Schätzung zeigen, dass sowohl die Arbeitsbedingungen als auch der Haushaltskontext krankheitsbedingte Fehlzeiten beeinflussen, und zwar für Frauen wie für Männer. Geschlechterbezogene Unterschiede bestehen insbesondere in Hinblick auf die relative Bedeutung der Arbeitsbedingungen sowie auf das Zusammenleben mit Kindern über drei Jahren. Diese Ergebnisse belegen die Überlegenheit des von uns gewählten umfassenderen Forschungsansatzes gegenüber der genannten zweigeteilten Forschungsperspektive.
Work-Family-Balance im Topmanagement
Authors: Jacobshagen Nicola , Amstad Fabienne T. , Semmer Norbert K. , Kuster Martin
Published: January 2007

Zusammenfassung. Das Topmanagement ist eine eher selten untersuchte Population. In dieser Untersuchung wurden in Zusammenarbeit mit einem Schweizer Großkonzern die Ausprägungen verschiedener Stressoren und Ressourcen in der Arbeit und deren Zusammenhänge mit Befindensparametern im Topmanagement (N = 143) analysiert. Der Konflikt Arbeit - Familie war in dieser Population stark ausgeprägt und korrelierte erwartungsgemäß mit arbeitsbezogenen Stressoren (r = .23 bis .48). In hierarchischen Regressionsanalysen sagte er die drei Befindensparameter Irritation, psychosomatische Beschwerden und arbeitsbezogene Depressivität vorher, auch wenn Ressourcen (positive soziale Beziehungen und Handlungsspielraum) und arbeitsbezogene Stressoren (Überlastung, Arbeitsplatzunsicherheit und Anzahl der Arbeitsstunden) kontrolliert wurden. Mediationsanalysen zeigten, dass der Konflikt Arbeit - Familie die Beziehungen zwischen den drei arbeitsbezogenen Stressoren und den drei Befindensbeeinträchtigungen fast immer mediierte.
Stand und Perspektiven der Personalpsychologie
Authors: Schuler Heinz
Published: January 2007

Zusammenfassung. Würde das Fachgebiet Personalpsychologie lediglich als inhaltlicher Teilbereich der Arbeits- und Organisationspsychologie definiert, bliebe unberücksichtigt, dass Fragestellungen der Forschung und Anwendung je nach Kontext und Zielsetzung als organisations-, arbeits- oder spezifisch personalpsychologisch anzusehen sind. Hier wird Personalpsychologie charakterisiert durch ihre primäre Konzentration auf das Individuum, durch ihre Ausrichtung auf die Tätigkeitsfelder Beruf und Personal, durch ihre differenzialpsychologische Orientierung sowie durch eine quasi naturwissenschaftliche Arbeitshaltung. An inhaltlichen Beispielen wird erörtert, inwieweit der Personalpsychologie eine Vorreiterrolle innerhalb der Arbeits- und Organisationspsychologie zugesprochen werden kann. Es wird aber auch auf Defizite hingewiesen, die beispielsweise in der Theoriebildung und -prüfung liegen, sowie auf Schwierigkeiten der Zusammenarbeit und Forschungskommunikation, in der sich ein Fachgebiet findet, das sich gleichzeitig an hohen wissenschaftlichen Standards orientiert und um praktische Nutzbarkeit bemüht. Abschließend werden Fragen der Ausbildung und Spezialisierung angesprochen, und es werden Vorschläge zu mutmaßlich fruchtbaren Forschungsthemen vorgebracht.
Arbeitsmarkt und demografischer Wandel
Authors: Allmendinger Jutta , Ebner Christian
Published: January 2007

Zusammenfassung. Auf dem deutschen Arbeitsmarkt kommt es zu tief greifenden Veränderungen. Der demografische Wandel führt zu einem Rückgang der Bevölkerungszahlen und setzt einen erheblichen Alterungsprozess der deutschen Gesellschaft in Gang. Abhängig von der Höhe der Zuwanderung verringert sich damit auch das Angebot an Arbeitskräften, und ältere Arbeitnehmer stellen einen immer größeren Teil der Belegschaften - vor allem in Ostdeutschland. Überdies wandelt sich die Struktur der Beschäftigung. Das Normalarbeitsverhältnis erodiert und Beschäftigungssektoren verändern sich. Insbesondere die Expansion anspruchsvoller Dienstleistungstätigkeiten erhöht den Bedarf an hoch qualifizierten Arbeitskräften, während Niedrigqualifizierte zunehmend seltener nachgefragt werden und bereits heute ein enormes Arbeitslosigkeitsrisiko tragen. Das schrumpfende Arbeitskräfteangebot, die immer älteren Arbeitsanbieter und die erhöhten Qualifikationsanforderungen verlangen nach einer Erhöhung der Erwerbstätigenquoten von Frauen und Älteren sowie nach einer effektiveren und verstärkten Bildung und Weiterbildung. Es bedarf zudem einer Neuordnung der Lebensverlaufspolitik. Der Normallebensverlauf und das Normalarbeitsverhältnis sind kaum mehr die Regel, alternative Lebensverläufe müssen institutionalisiert und systematische Unterbrechungen für z. B. Weiterbildung, die Pflege Älterer oder Kinderbetreuung gefördert und gefordert werden.
Zur Stabilität und Validität von Entwicklungstestergebnissen im Alter von sechs Monaten bis zwei Jahren
Authors: Lissmann Ilka , Domsch Holger , Lohaus Arnold
Published: January 2007

Zusammenfassung. Berichtet wird über die Durchführung zweier Studien zur Stabilität und Validität der Erhebung des Entwicklungsstandes in der frühen Kindheit. Eingesetzt wurde der Entwicklungstest 6 Monate - 6 Jahre (ET 6-6). In der ersten Studie wird über eine Längsschnittuntersuchung bei 87 Kindern im Alter von 6 bis 24 Monaten berichtet, wobei der ET 6-6 mit 6, 12 und 24 Monaten erhoben wurde. Neben dem ET 6-6 wurde zur Validierung ein Sprachtest für zweijährige Kinder (der SETK-2) eingesetzt. Es zeigten sich in allen Altersstufen signifikante Beziehungen zwischen den Dimensionen des ET 6-6, wobei signifikante Stabilitäten jedoch nur über einen Zeitraum von sechs Monaten feststellbar waren (von 6 auf 12 Monate). Es zeigten sich weiterhin Bezüge zum SETK-2, die teilweise die prognostische Validität des ET 6-6 belegen. In der zweiten Studie wurden bei sechs bis neun Monate alten Kindern neben dem ET 6-6 die Bayley Scales of Infant Development eingesetzt. Darüber hinaus wurden zur Validitätsprüfung Elternurteile zu den Items des ET 6-6 erhoben. Es zeigten sich teilweise signifikante Bezüge zwischen den beiden Entwicklungstests (insbesondere bei den Motorikskalen und den Gesamtscores). Weiterhin konnten hohe Übereinstimmungen zwischen den Elternurteilen und den testbasierten Scores erzielt werden. Die Bedeutung der Ergebnisse für die Diagnostik im frühen Kindesalter wird abschließend diskutiert.
Cognitive Aging in a Precision Sport Context
Authors: Molander Bo , Bäckman Lars
Published: January 2007

Highly skilled miniature golf players were examined in a series of field and laboratory studies. The principal finding from these studies is that young and young adult players (range = 15-38 years) score equally well or better in competition than in training whereas older adult players (range = 46-73 years) perform worse in competitive events than under training conditions. It was also found that the impairment in motor performance on the part of the older players is associated with age-related deficits in basic cognitive abilities, such as memory and attention. These results support the hypothesis that older players may be able to compensate for age-related deficits under relaxed conditions, but not under conditions of high arousal. The possibility of improving the performance of the older players in stressful situations by means of various intervention programs is discussed.
The Autonomous-Relational Self
Authors: Kagitçibasi Çigdem
Published: January 2007

Autonomy is often construed as separateness from others and is seen to result from a separation-individuation process. However, it is neither logically nor psychologically necessary for autonomy to imply separateness if the existence of the two different dimensions of agency and interpersonal distance are recognized. The two poles of the agency dimension are autonomy and heteronomy; those of the interpersonal distance dimension are separateness and relatedness. The two dimensions are confused when agency is pitted against relatedness. Different family interaction models are examined here in terms of childrearing patterns and the resultant types of (developing) selves. One of these, the autonomous-relational self, is suggested in this article to be a healthy synthesis of the two basic human needs for agency and relatedness. It tends to develop in the family model of emotional interdependence involving authoritative parenting. This family model and self constellation, which are supported by research evidence, involve a different set of theories than are traditionally found in psychology. This conceptualization synthesizes some apparently conflicting patterns of interpersonal relations and the self. It may serve as a corrective to the pervasive emphasis in psychology on individual autonomy at the cost of human relatedness.
What Is the Cognitive System's Preferred Route for Deriving Phonology from Print?
Authors: Raman Ilhan , Baluch Bahman , Sneddon Peter
Published: January 2007

The present study examined the manner in which Turkish readers read aloud words printed in shallow (transparent) Turkish orthography. The first experiment showed that when the set consists of only word stimuli there is a significant word-frequency effect. This indicates that readers had made reference to lexical information for naming. The result of a second experiment, on the other hand, showed that when an equal number of nonwords are embedded in the stimulus set the word-frequency effect disappears. This indicates that readers had made reference to nonlexical information for naming. These results support the ideas that: (a) the preferred route for naming amongst readers of Turkish script is lexical, regardless of the orthographic-phonological transparency; and (b) the naming process is indeed a flexible one in which task demands may affect the nature of the route used for naming. The above findings are discussed in relation to research on shallow and deep (nonshallow) orthographies .
An Implicit Theory of Perceived Control
Authors: Ferguson Eamonn , Cox Tom
Published: January 2007

This article examines individuals' implicit theory of perceived control. Three studies are reported (N's = 77, 87, 45). The results demonstrate that individuals' implicit theory of perceived control is based on two orthogonal dimensions (stability-instability and contingency). The similarities between this model and the work of others (e.g., Bandura, 1977 ) are made, and a common conceptual framework is identified. Finally, the notion of mediated control is developed and explored.
Pavlovian Conditioning to Social Stimuli
Authors: Parra Cristina , Esteves Francisco , Flykt Anders , Öhman Arne
Published: January 2007

Using a Pavlovian procedure, human subjects were conditioned to pictures of angry faces with a mild electric shock as the unconditioned stimulus. They were then tested with backward masking conditions preventing conscious recognition of the facial stimuli. In the first experiment a shock followed a particular nonmasked angry face which was exposed among many other faces. Although the subjects did not rate this face as familiar in a subsequent test when is was presented masked among other masked and nonmasked faces, it elicited larger skin conductance responses than did nonshocked control faces. This dissociation between explicit recognition and implicit skin conductance differentiation was replicated in the second experiment, in which the subjects rated their shock expectancy. Although conditioning resulted in much better differentiation between conditioned and control faces during nonmasked than masked test-trials, skin conductance differentiation did not differ between the two masking conditions.
The Emergence of Intentional Communication in Ontogeny, Phylogeny, and Pathology
Authors: Camaioni Luigia
Published: January 2007

The emergence of intentional gestural communication around the end of the first year of life is widely recognized as a basic milestone in the infant's communicative development. Two types of comparison are carried out in this paper. The first comparison concerns the gestural communication of human infants and of our nearest primate relatives, the apes, and especially the well-studied chimpanzees. The second comparison considers a special case of gestural communication, namely children with autism, who fail to develop some important forms of communication, language, and social interaction that normal infants develop in the first 2 years of life. In seeking to explain the patterns of similarities and differences derived from these two comparisons, the possible role of several developmental processes will be considered and evaluated: social sensitivity, sensitivity to eye contact and gaze, understanding of agency, and understanding of subjectivity.
The Nature of Trait Anxiety
Authors: Calvo Manuel G. , Cano-Vindel Antonio
Published: January 2007

This paper examines the nature of trait anxiety using self-report and objective measures of biological, behavioral, and cognitive characteristics as predictors in multiple regression analyses. Trait anxiety was associated with self-reported psychological maladjustment and psychosomatic disorders, but not with actual physical capacity and skills, cardiovascular fitness, or biochemical parameters. Under social-evaluative stress, trait anxiety was associated with self-reported cognitive and somatic state anxiety, but only slightly with actual behavioral anxiety (only gaze avoidance) and physiological arousal (only heart rate recovery). There was high stability in relationships over a 3-month period. These results favor a cognitive, rather than a biological, conceptualization of trait anxiety. It is suggested that a cognitive bias to focus on internal threat-related stimuli is a vulnerability factor in trait anxiety that predisposes to anxiety disorders.
Mercury in vegetation and organic soil at an upland boreal forest site in Prince Albert National Park, Saskatchewan, Canada
Authors: Friedli H. R. , Radke L. F. , Payne N. J. , McRae D. J. , Lynham T. J. , Blake T. W.
Published: January 2007

We studied an upland boreal forest plot located in the Prince Albert National Park, Saskatchewan, Canada, to measure the total mercury content in vegetation and organic soil with a view to assessing the potential for mercury release during forest fires. The study area consists of two stands of vegetation regrown after fires 39 and 130 years ago, with different carbon and mercury stocks in vegetation and organic soil. The mercury concentrations in ng g−1 (dry weight) were measured for moss (90–110), leaves (8), needles (10), bark (16–38), lichen (30–227), bole wood (2) and for organic soil layers (120–300). The combined mercury stock increased from 1.01 ± 0.28 to 3.45 ± 0.87 mg m−2 for the two stand ages; 93–97% of the mercury resided in the organic soil to the mineral layer. The mercury input to the ecosystem is from wet and dry deposition and is trapped in the organic soil layers as indicated by the high organic soil mercury concentrations and low mercury concentration in the underlying mineral layer. Extrapolation from the data measured for the two subplots to all boreal forests suggests a massive mercury stock in boreal forests (15,000 to 44,000 t). This is a low estimate because boreal lowlands have still higher mercury densities. Not all of the organic soil mercury was acquired since the last burns; some predates the more recent fires. The mercury being predominantly located in the organic soil makes fire severity the most important parameter for mercury release. The anticipated accelerated warming in northern latitudes would increase severity, frequency and burn area of future fires and result in large pulses of mercury to the atmosphere and further stress to the environment.
Dominance of organic nitrogen from headwater streams to large rivers across the conterminous United States
Authors: Scott Durelle , Harvey Judson , Alexander Richard , Schwarz Gregory
Published: January 2007

The frequency and magnitude of hypoxic areas in coastal waterbodies are increasing across the globe, partially in response to the increase in nitrogen delivery from the landscape (Diaz, 2001; Rabalais et al., 2002). Although studies of annual total nitrogen and nitrate yields have greatly improved understanding of the contaminant sources that contribute to riverine nitrogen loads (Alexander et al., 2000; Caraco and Cole, 1999), the emphasis of these studies on annual timescales and selected nitrogen forms is not sufficient to understand the factors that control the cycling, transport, and fate of reactive nitrogen. Here we use data from 850 river stations to calculate long‐term mean‐annual and interannual loads of organic, ammonia, and nitrate‐nitrite nitrogen suitable for spatial analysis. We find that organic nitrogen is the dominant nitrogen pool within rivers across most of the United States and is significant even in basins with high anthropogenic sources of nitrogen. Downstream organic nitrogen patterns illustrate that organic nitrogen is an abundant fraction of the nitrogen loads in all regions. Although the longitudinal patterns are not consistent across regions, these patterns are suggestive of cycling between ON and NO3− on seasonal timescales influenced by land use, stream morphology, and riparian connectivity with active floodplains. Future regional studies need to incorporate multinitrogen species at intraannual timescales, as well as stream characteristics beyond channel depth, to elucidate the roles of nitrogen sources and in‐stream transformations on the fate and reactivity of riverine nitrogen transported to coastal seas.
Sharpness of the extratropical tropopause in baroclinic life cycle experiments
Authors: Wirth V. , Szabo T.
Published: January 2007

The sharpness of the extratropical tropopause is investigated using baroclinic life cycle experiments. In these simulations, slow synoptic scale dynamics leads to a net tropopause sharpening. The mechanism involves vertical convergence of the ageostrophic wind. The results support earlier suggestions from idealized theoretical studies.
Wind/WAVES observations of high‐frequency plasma waves in solar wind reconnection exhausts
Authors: Huttunen K. E. J. , Bale S. D. , Phan T. D. , Davis M. , Gosling J. T.
Published: January 2007

This paper studies high‐frequency plasma waves during 28 encounters of the Wind spacecraft with solar wind reconnection exhausts. We use measurements by the Thermal Noise Receiver (TNR) and Time Domain Sampler (TDS) experiments on Wind/WAVES to survey characteristics of electron plasma waves and the most common regions where they are found. TNR spectrograms showed intense emission bursts ∼4 kHz (corresponding to the ion acoustic range) during 79% of the events while around the local electron plasma frequency intense emission bursts were recorded for 39% of the events. The TDS instrument, operating at 120,000 samples per second, detected three kinds of electric waveforms: Langmuir waves, electron solitary waves (ESW), and wave packets with frequencies between ion and electron plasma frequencies typically interpreted as Doppler‐shifted ion acoustic waves. Except for one very intense ESW event, the average amplitudes for all these three waveform types were similar, below 1 mV/m. We found an increased probability to observe intense plasma wave activity when the reconnection X‐line region was approached. Wave activity may be present anywhere in the reconnection exhaust, although the boundary region of the exhaust appears to be the most dynamic region for wave activity. In particular, the majority of the captured ESW occurred near the exhaust boundaries.
Evaluation of HYCOM in the Kuroshio Extension region using new metrics
Authors: Kelly Kathryn A. , Thompson LuAnne , Cheng Wei , Metzger E. Joseph
Published: January 2007

A high resolution (0.08° at equator) HYbrid Coordinate Ocean Model (HYCOM) simulation is evaluated using observations for the period 1993–2003 for a western Pacific region containing the Kuroshio Extension (KE) (25–45°N and 135–180°E). Comparisons are made for the KE path and strength and for the upper ocean heat budget. The mean strength and path agree well with observations, except near the KE separation point, where the jet is as much as 2° of latitude too far south. However, the model path variations are considerably more energetic than observed, and this likely obscures the observed tendency for weaker meandering when the KE is strong. The model accurately reproduces seasonal variations of upper ocean heat content, but the long‐period (about 10‐yr) variations of heat content and KE strength clearly differ in the region upstream of 150°E. The long‐period variations in model SSH do not show the same relationship to wind forcing that is seen in the observations and in a low‐resolution ocean model simulation. The HYCOM upper ocean heat budget is similar to a diagnostic heat budget inferred from observations in that the dominant contribution is from lateral fluxes (advection); however, advection fluctuations (again primarily in the upstream region) are much larger in the model. This evaluation of HYCOM shows realistic mean quantities and realistic variations away from the separation region. However, an overly energetic jet upstream of 150°E can obscure the longer period variability and its contribution to the upper ocean heat budget.
Global assessment of marine boundary layer cloud droplet number concentration from satellite
Authors: Bennartz R.
Published: January 2007

Global satellite data are used to infer the droplet number concentration of marine boundary layer clouds. In a first step, two and a half years (July 2002 to December 2004) of Moderate Resolution Imaging Spectroradiometer (MODIS, on board NASA's Aqua satellite) level 3 data estimates of cloud effective radius and optical thickness are used to derive cloud droplet number concentration N and cloud geometrical thickness H under the assumption of adiabatically stratified clouds. Theoretical error estimates show that for a liquid water path higher than 30 g/m2 and a cloud fraction higher than 0.8, H (N) can be derived with a relative uncertainty of better than 20% (80%). To further validate the estimates of N and H, cloud liquid water path is calculated and compared to independent observations of cloud liquid water path from the passive microwave Advanced Microwave Scanning Radiometer (AMSR‐E), also on board Aqua. Good agreement between the two different data sets is found. In a second step, the global distribution of cloud droplet number concentration in stratiform boundary layer clouds is evaluated. The data are separated into observations that are likely to be drizzling and drizzle‐free using published relations between drizzle rate and N and H. It is found that the mean droplet number concentration over remote Northern Hemisphere oceans is higher than over the southern oceans (64–89 cm−3 in the Northern Hemisphere and 40–67 cm−3 in the Southern Hemisphere). Leeward of the major continents cloud droplet number concentration is generally high with maximum values close to the coasts. On the Southern Hemisphere, especially over the east Pacific Ocean, microphysical conditions were almost constant through the entire observation period. Over the southeast Atlantic Ocean, the cloud microphysical variability appears to be strongly influenced by the dry biomass burning season in Africa.
Control of downward migration of dense nonaqueous phase liquid during surfactant flooding by design simulations
Authors: Jin Minquan , Hirasaki George J. , Jackson Richard E. , Kostarelos Konstantinos , Pope Gary A.
Published: January 2007

Sand tank experiments have been used to study a surfactant‐enhanced aquifer remediation (SEAR) process during which downward migration of dense nonaqueous phase liquid (DNAPL) has been observed in some of these experiments. Through numerical simulation of one particular sand tank experiment conducted at Sandia National Laboratories we show in this paper that this downward migration of DNAPL can be anticipated and controlled even in a very difficult geosystem environment. The results indicate that design simulations play a significant role in the design of either laboratory column experiments or field SEAR application and that surfactant flooding can be accomplished without loss of hydraulic control of DNAPL under typical alluvial aquifer/aquitard conditions and with only minor vertical mobilization within the aquifer (i.e., <1% of the DNAPL present). The design simulations are considered as a sensitivity analysis exercise in which the heterogeneity in the permeability field and DNAPL saturation and other critical variables are varied to produce a robust design. The simulation results indicate that the significant downward mobilization of DNAPL as observed in the Sandia sand tank experiment is a result of the use of high‐permeability materials, weak viscous (horizontal) forces, and low surfactant solubilization potential. The downward mobilization of DNAPL is a design issue to be evaluated and controlled rather than an inevitable consequence of the use of surfactants to remove DNAPL.
Cylindrical and spherical quantum ion acoustic waves
Authors: Sahu Biswajit , Roychoudhury Rajkumar
Published: January 2007

Cylindrical and spherical deformed Korteweg–de Vries (dKdV) equations are derived for quantum ion acoustic waves in an unmagnetized two species quantum plasma system, comprised of electrons and ions, by the reductive perturbation technique in the weakly nonlinear limit. The properties of quantum ion acoustic solitary waves are studied taking into account the quantum mechanical effects in a nonplanar cylindrical or spherical geometry, which differs from one-dimensional planar geometry. Both analytical and numerical solutions of the dKdV equations are discussed in some detail. There exists a critical value of quantum parameters beyond which the quantum ion acoustic soliton collapses. It is also found that for the critical values of H, viz., H=2, some nontrivial analytical solution exists for both cylindrical and spherical dKdV equations.
Defect states in the high-dielectric-constant gate oxide HfSiO4
Authors: Xiong K. , Du Y. , Tse K. , Robertson J.
Published: January 2007

Hafnium silicate has a high dielectric constant and is a leading candidate to act as a gate dielectric. The defect energy levels have been calculated. The oxygen vacancy is found to give rise to Si-like levels which lie within the band gap of Si. The vacancy states are very localized and are localized on the neighboring Si sites. A second defect level high in the oxide gap is localized on the Hf sites. The behavior of ZrSiO4 is similar.
Spectroscopic investigation of an electrochemically controlled conducting polymer-solid electrolyte junction
Authors: Berzina Tatiana , Erokhin Victor , Fontana M. P.
Published: January 2007

We have recently reported a hybrid conducting polymer-solid electrolyte heterojunction in which electronic channel current is controlled by ionic diffusion and redox reactions involving doped polyethyleneoxide and doped polyaniline (PANI). In this paper we demonstrate on the microscopic level the validity of the model we proposed to interpret the electronic behavior of the device we fabricated. In particular, we used resonance and vicinity (surface-enhanced-Raman-scattering like) enhanced micro-Raman spectroscopy to map out the redox state of PANI along the conducting channel, simultaneously with the determination of the voltamperometric characteristics in a potentiostat configuration. The Raman data were complemented as appropriate by the optical and Fourier transform infrared absorption spectroscopies.
Chirality and stability of vortex state in Permalloy triangular ring micromagnets
Authors: Vavassori P. , Donzelli O. , Grimsditch M. , Metlushko V. , Ilic B.
Published: January 2007

We present the results of a study of the magnetization reversal in Permalloy triangular rings using diffracted magneto-optics Kerr effect combined with numerical micromagnetic simulations and in-field magnetic force microscopy. Diffracted loops show a two-step switching process for external fields along or perpendicular to any of the ring edges. The diffracted loops calculated from micromagnetic simulations reproduce the measured ones and show that the switching occurs from one asymmetric onion state to the reversed state, for both directions of the applied field. In both cases a stable intermediate vortex state appears during the switching, accounting for the diffracted loop structures. The stability and the magnetization chirality of the vortex state depend on the direction of the applied field relative to the ring orientation. Magnetization configurations occurring during reversal imaged with magnetic force microscopy operated applying an external field confirm the above reversal process.
Structure, energy, and IR spectra of I2∙−.nH2O clusters (n=1–8): A theoretical study
Authors: Pathak A. K. , Mukherjee T. , Maity D. K.
Published: January 2007

The authors report theoretical results on structure, bonding, energy, and infrared spectra of iodine dimer radical anion hydrated clusters, I2∙−.nH2O (n=1–8), based on a systematic study following density functional theory. Several initial guess structures are considered for each size cluster to locate minimum energy conformers with a Gaussian 6-311++G(d,p) split valence basis function (triple split valence 6-311 basis set is applied for iodine). It is observed that three different types of hydrogen bonded structures, namely, symmetrical double hydrogen bonding, single hydrogen bonding, and interwater hydrogen bonding structures, are possible in these hydrated clusters. But conformers having interwater hydrogen bonding arrangements are more stable compared to those of double or single hydrogen bonded structures. It is also noticed that up to four solvent H2O units can reside around the solute in interwater hydrogen bonding network. At the maximum six H2O units are independently linked to the dimer anion having four double hydrogen bonding and two single hydrogen bonding, suggesting the hydration number of I2∙− to be 6. However, conformers having H2O units independently linked to the iodine dimer anion are not the most stable structures. In all these hydrated clusters, the odd electron is found to be localized over two I atoms and the two atoms are bound by a three-electron hemi bond. The solvation, interaction, and vertical detachment energies are calculated for all I2∙−.nH2O clusters. Energy of interaction and vertical detachment energy profiles show stepwise saturation, indicating geometrical shell closing in the hydrated clusters, but solvation energy profile fails to show such behavior. A linear correlation is observed between the calculated energy of interaction and vertical detachment energy. It is observed that formation of I2∙−-water cluster induces significant shifts from the normal O–H stretching modes of isolated H2O. However, bending mode of H2O remains insensitive to the successive addition of solvent H2O units. Weighted average energy profiles and IR spectra are reported for all the hydrated clusters based on the statistical population of individual conformers at room temperature.
Work function of Ni3Si2 on HfSixOy and SiO2 and its implication for Ni fully silicided gate applications
Authors: Kittl J. A. , O’Sullivan B. J. , Kaushik V. S. , Lauwers A. , Pawlak M. A. , Hoffmann T. , Demeurisse C. , Vrancken C. , Veloso A. , Absil P. , Biesemans S.
Published: January 2007

The effective work function (WF) of Ni3Si2 was evaluated on HfSixOy and SiO2 dielectrics. Ni3Si2 forms, in thin film Ni–Si diffusion couples with Ni to Si composition ratios between 1 and 2, after formation of a Ni2Si∕NiSi stack and by its reaction at moderate thermal budgets (comparable to those used in back end processing of complementary metal-oxide-semiconductor circuits). Ni3Si2 formation limits, on the Ni-rich side, the process window for NiSi fully silicided (FUSI) gates (NiSi at interface with dielectric) to reacted Ni–Si ratios <1.5. The WF of Ni3Si2 was found to have similar values and behavior to that of NiSi, both on SiO2 (showing similar modulation with dopants) and on HfSixOy, in contrast to Ni-richer silicides such as Ni2Si and Ni31Si12 which do not exhibit significant WF modulation with dopants on SiO2 and have considerably higher WF on HfSixOy. This suggests that the chemistry and structure of the original NiSi/dielectric interface are not modified significantly by the subsequent growth of Ni3Si2 and implies that its formation may be tolerable when targeting NiSi FUSI gates, thereby expanding the process window for this application.
Growth and electrical properties of large size Pb(In1∕2Nb1∕2)O3–Pb(Mg1∕3Nb2∕3)O3–PbTiO3 crystals prepared by the vertical Bridgman technique
Authors: Xu Guisheng , Chen Kai , Yang Danfeng , Li Junbao
Published: January 2007

Relaxor-based ferroelectric single crystals Pb(In1∕2Nb1∕2)O3–Pb(Mg1∕3Nb2∕3)O3–PbTiO3 (PIMNT) have been grown directly from their melt using the vertical Bridgman method, and their boules have reached the size of ϕ45×80mm. The as-grown PIMNT28/40/32 crystals on the (001) cuts exhibit a dielectric constant ε∼5200, dielectric loss tanδ∼0.50%, piezoelectric strain constant d33∼1700–2200pC∕N, electromechanical coupling factors kt∼0.61 and k33∼0.92, coercive field Ec∼10.88kV∕cm, remanent polarization Pr∼46μC∕cm2, Curie temperature TC∼192°C, and rhombohedral to tetragonal phase transition temperature Trt∼119°C. Moreover, their piezoelectric properties show good thermal stability under the heat treatment at 105°C.
Coulomb blockade and Kondo effect in a few-electron silicon/silicon-germanium quantum dot
Authors: Klein Levente J. , Savage Donald E. , Eriksson Mark A.
Published: January 2007

Transport measurements at cryogenic temperatures through a few-electron top gated quantum dot fabricated in a silicon/silicon-germanium heterostructure are reported. Variations in gate voltage induce a transition from an isolated dot toward a dot strongly coupled to the leads. In addition to Coulomb blockade, when the dot is strongly coupled to the leads, the authors observe the appearance of a zero bias conductance peak due to the Kondo effect. The Kondo peak splits in a magnetic field, and the splitting scales linearly with the applied field. They also observe a transition from pure Coulomb blockade to peaks with a Fano line shape.
Efficient all-fiber bismuth-doped laser
Authors: Razdobreev I. , Bigot L. , Pureur V. , Favre A. , Bouwmans G. , Douay M.
Published: January 2007

In the present letter the authors report on the realization of an all-fiber bismuth-doped laser with laser emission that can be chosen with corresponding fiber Bragg gratings between at least 1150 and 1225nm. In their experiments they achieved a slope efficiency of about 24% at 1200nm, which is the highest reported for this kind of laser.
Low-temperature growth of ZnO nanorods in anodic aluminum oxide on Si substrate by atomic layer deposition
Authors: Yang Ching-Jung , Wang Shun-Min , Liang Shih-Wei , Chang Yung-Huang , Chen Chih , Shieh Jia-Min
Published: January 2007

Low-temperature growth of self-organized ZnO nanorods on Si substrate is achieved using anodic aluminum oxide and atomic layer deposition at 250°C without catalyst or seed layer. Photoluminescence spectrum indicates that the ZnO nanorod arrays exhibit a blue∕green luminescence at 480nm. In addition, the nanorod arrays demonstrate excellent field-emission properties with a turn-on electric field of 6.5Vμm−1 and a threshold electric field of 9.8Vμm−1, which are attributed to the perfectly perpendicular alignment of ZnO nanorods to the Si substrate.
Density functional theoretical determinations of electronic and optical properties of nanowires and bulks for CdS and CdSe
Authors: Huang S.-P. , Cheng W.-D. , Wu D.-S. , Hu J.-M. , Shen J. , Xie Z. , Zhang H. , Gong Y.-J.
Published: January 2007

The authors present density functional theoretical results of electronic and optical properties of wurtzite-type CdS and CdSe semiconductor nanowires and bulks. The results show that quantum confinement will increase the energy gap, decrease the dielectric function, change the sign of birefringence, and increase the absolute value of birefringence at low-frequency region, as the dimensions of CdS and CdSe are reduced from the bulk to a nanowire with diameter of several nanometers. The optical spectral peaks of CdSe nanowires show redshifts as compared with the corresponding ones of CdS nanowires.
Using historical records, aerial photography and dendroecological methods to determine vegetation changes in a grassy woodland since European settlement
Authors: Franco Julia A. , Morgan John W.
Published: January 2007

By using historical records, aerial photography and dendroecological methods, we assessed the vegetation changes that have occurred in a grassy-woodland landscape at Inverleigh, Victoria, since 1850. Land managers have perceived that encroachment by native shrubs such as Acacia paradoxa DC. has occurred in woodlands in the area after their reservation for conservation following a long period of stock grazing, but data are needed to place these recent changes in context. The vegetation has passed through three management phases since early European settlement and these have contributed to the present vegetation patterns. The area was (1) initially set aside as a timber reserve at the time of European settlement and was periodically grazed by stock. (2) Logging, plantation forestry and stock grazing regimes caused large-scale disturbances to the understorey vegetation during the early 1900s and continued to the 1980s. In the 1970s, disturbances caused by recreational activities intensified the vegetation modification. During this time, the vegetation changed from an open woodland to denser, shrubbier woodland. Most soil disturbances ceased when (3) the area was declared a flora reserve in 1988. Evidence suggests that with the cessation of these disturbances, populations of the native shrub Acacia paradoxa increased dramatically, reducing the tree-gap area significantly. The major increase occurred from 1974 to 2002 when the area of tree gap declined by 38%. Age-class analyses suggested that most (>80%) of the A. paradoxa population is less than 25 years old, but plants may be able to live beyond 60 years. Logistic regression modelling suggested that distance to closest track influences present-day A. paradoxa distribution, as does soil moisture. This suggests that the soil disturbance from grading tracks and vehicle movements may be facilitating both the spread and initial establishment of A. paradoxa, particularly on soils of higher soil-moisture holding capacity. Strategies for future woodland management must consider how the current vegetation dynamics reflect past land-use history, and land managers must choose appropriate goals for biodiversity conservation in the light of these changes.
Alterations of cellular bioenergetics in pulmonary artery endothelial cells
Authors: Xu Weiling , Koeck Thomas , Lara Abigail R. , Neumann Donald , DiFilippo Frank P. , Koo Michelle , Janocha Allison J. , Masri Fares A. , Arroliga Alejandro C. , Jennings Constance , Dweik Raed A. , Tuder Rubin M. , Stuehr Dennis J. , Erzurum Serpil C.
Published: January 2007

Idiopathic pulmonary arterial hypertension (IPAH) is pathogenetically related to low levels of the vasodilator nitric oxide (NO). Because NO regulates cellular respiration and mitochondrial biogenesis, we hypothesized that abnormalities of bioenergetics may be present in IPAH. Evaluation of pulmonary artery endothelial cells from IPAH and control lungs
in vitro
revealed that oxygen consumption of IPAH cells was decreased, especially in state 3 respiration with substrates glutamate-malate or succinate, and this decrease paralleled reduction in Complex IV activity and IPAH cellular NO synthesis. IPAH pulmonary artery endothelial cells had decreased mitochondrial dehydrogenase activity and lowered mitochondrial numbers per cell and mitochondrial DNA content, all of which increased after exposure to NO donors. Although IPAH/pulmonary artery endothelial cells' ATP content was similar to control under normoxia, cellular ATP did not change significantly in IPAH cells under hypoxia, whereas ATP decreased 35% in control cells, identifying a greater dependence on cellular respiration for energy in control cells. Evidence that glucose metabolism was subserving the primary role for energy requirements of IPAH cells was provided by the ≈3-fold greater glycolytic rate of IPAH cells. Positron emission tomography scan with [
18
F]fluoro-deoxy-
d
-glucose performed on IPAH patients and healthy controls revealed significantly higher uptake in IPAH lungs as compared with controls, confirming that the glycolytic rate was increased
in vivo
. Thus, there are substantial changes in bioenergetics of IPAH endothelial cells, which may have consequences for pulmonary hypertensive responses and potentially in development of novel imaging modalities for diagnosis and evaluation of treatment.
Transcriptional regulation of protein complexes within and across species
Authors: Tan Kai , Shlomi Tomer , Feizi Hoda , Ideker Trey , Sharan Roded
Published: January 2007

Yeast two-hybrid and coimmunoprecipitation experiments have defined large-scale protein–protein interaction networks for many model species. Separately, systematic chromatin immunoprecipitation experiments have enabled the assembly of large networks of transcriptional regulatory interactions. To investigate the functional interplay between these two interaction types, we combined both within a probabilistic framework that models the cell as a network of transcription factors regulating protein complexes. This framework identified 72 putative coregulated complexes in yeast and allowed the prediction of 120 previously uncharacterized transcriptional interactions. Several predictions were tested by new microarray profiles, yielding a confirmation rate (58%) comparable with that of direct immunoprecipitation experiments. Furthermore, we extended our framework to a cross-species setting, identifying 24 coregulated complexes that were conserved between yeast and fly. Analyses of these conserved complexes revealed different conservation levels of their regulators and provided suggestive evidence that protein–protein interaction networks may evolve more slowly than transcriptional interaction networks. Our results demonstrate how multiple molecular interaction types can be integrated toward a global wiring diagram of the cell, and they provide insights into the evolutionary dynamics of protein complex regulation.
IFN-stimulated gene 15 functions as a critical antiviral molecule against influenza, herpes, and Sindbis viruses
Authors: Lenschow Deborah J. , Lai Caroline , Frias-Staheli Natalia , Giannakopoulos Nadia V. , Lutz Andrew , Wolff Thorsten , Osiak Anna , Levine Beth , Schmidt Robert E. , García-Sastre Adolfo , Leib David A. , Pekosz Andrew , Knobeloch Klaus-Peter , Horak Ivan , Virgin Herbert Whiting
Published: January 2007

Type I interferons (IFNs) play an essential role in the host response to viral infection through the induction of numerous IFN-stimulated genes (ISGs), including important antiviral molecules such as PKR, RNase L, Mx, and iNOS. Yet, additional antiviral ISGs likely exist. IFN-stimulated gene 15 (ISG15) is a ubiquitin homolog that is rapidly up-regulated after viral infection, and it conjugates to a wide array of host proteins. Although it has been hypothesized that ISG15 functions as an antiviral molecule, the initial evaluation of ISG15-deficient mice revealed no defects in their responses to vesicular stomatitis virus or lymphocytic choriomeningitis virus, leaving open the important question of whether ISG15 is an antiviral moleculein vivo. Here we demonstrate that ISG15 is critical for the host response to viral infection. ISG15−/−mice are more susceptible to influenza A/WSN/33 and influenza B/Lee/40 virus infections. ISG15−/−mice also exhibited increased susceptibility to both herpes simplex virus type 1 and murine gammaherpesvirus 68 infection and to Sindbis virus infection. The increased susceptibility of ISG15−/−mice to Sindbis virus infection was rescued by expressing wild-type ISG15, but not a mutant form of ISG15 that cannot form conjugates, from the Sindbis virus genome. The demonstration of ISG15 as a novel antiviral molecule with activity against both RNA and DNA viruses provides a target for the development of therapies against important human pathogens.
Deprivation-induced synaptic depression by distinct mechanisms in different layers of mouse visual cortex
Authors: Crozier Robert A. , Wang Yun , Liu Cheng-Hang , Bear Mark F.
Published: January 2007

Long-term depression (LTD) induced by low-frequency synaptic stimulation (LFS) was originally introduced as a model to probe potential mechanisms of deprivation-induced synaptic depression in visual cortex. In hippocampus, LTD requires activation of postsynaptic NMDA receptors, PKA, and the clathrin-dependent endocytosis of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. It has long been assumed that LTD induced in visual cortical layer 2/3 by LFS of layer 4 uses similar mechanisms. Here we show in mouse visual cortex that this conclusion requires revision. We find that LTD induced in layer 2/3 by LFS is unaffected by inhibitors of PKA or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor endocytosis but is reliably blocked by an endocannabinoid CB1 receptor antagonist. Conversely, LFS applied to synapses on layer 4 neurons produces LTD that appears mechanistically identical to that in CA1 and is insensitive to CB1 blockers. Occlusion experiments suggest that both mechanisms contribute to the loss of visual responsiveness after monocular deprivation.