bluuebunny/crossref_metadata_2025 huggingface dataset:
Are Working Memory and Attention Related Constructs?
Authors: Buehner Markus , Mangels Marija , Krumm Stefan , Ziegler Matthias
Published: October 2005

Abstract. The purpose of this study was to replicate the working memory model proposed by Oberauer, Suess, Wilhelm, and Wittmann (2000) and to clarify its relationship to selective attention. Eleven working memory and attention tests were administered to 125 students. Using structural equation models, we were able to confirm a facet model of working memory with three functional and two content factors. Thus, the present study provides further evidence for a facet model of working memory. Additionally, the factor selective attention was added to this model. We found only low to moderate correlations between selective attention and functional working memory factors. Therefore, this study provides further evidence that selective attention, as measured by the Testbattery for Attentional Performance (TAP), and working memory are distinct concepts.
Is Openness to Experience an Independent Personality Dimension?
Authors: García Luis F. , Aluja Anton , García Óscar , Cuevas Lara
Published: October 2005

Abstract. The Openness to Experience personality dimension has been challenged for its lack of independence from other personality constructs. In order to test whether Openness is an independent trait, we applied the following psychometric tests to a sample of 1006 nonpsychology university students: NEO-PI-R, EPQ-RS, ZKPQ-III-R, and SSS-V. Results suggest that most of the Openness variance remains to be explained. Therefore, this domain can be considered independent within the personality area, although Extraversion and, above all, Sensation Seeking presented significant relationships with the Openness scales. Each NEO-PI-R Openness facet shows a different pattern of relationships with other personality constructs proposed by the Five-Factor, Eysenck's, and Zuckerman's theories. Those relationships are discussed.
Hydrological controls on diurnal ice flow variability in valley glaciers
Authors: Nienow P. W. , Hubbard A. L. , Hubbard B. P. , Chandler D. M. , Mair D. W. F. , Sharp M. J. , Willis I. C.
Published: October 2005

This paper uses a combination of field data and three‐dimensional modeling to investigate the spatial variability in basal conditions required to induce observed fluctuations in diurnal ice velocity at Haut Glacier d'Arolla, Switzerland. A network of surface velocity markers was observed at intervals of as little as four hours over diurnal cycles in both winter and late summer. Winter motion showed limited diurnal variability, presumably due to the absence of supraglacial meltwater inputs. By contrast, diurnal fluctuations in ice motion were recorded in summer across the lower and upper glacier. In the lower glacier, surface velocities were intimately linked to hydrological forcing in the vicinity of a subglacial channel. Previously observed diurnal excursions of meltwater away from the channel should reduce areas of basal drag adjacent to the channel thereby impacting on ice dynamics. Using a first‐order ice flow approximation, we investigated the distribution of basal shear traction adjacent to the channel necessary to replicate the observed surface velocity field during periods of rapid ice motion. The modeling suggests that the observed variations in diurnal velocity will only occur with extensive reductions in basal drag across a transverse zone of up to 560 m across, well beyond the immediate vicinity and previously observed extent of diurnal excursions of meltwater away from the subglacial channel.
On the connection between South Pacific subtropical spiciness anomalies and decadal equatorial variability in an ocean general circulation model
Authors: Luo Yiyong , Rothstein Lewis M. , Zhang Rong‐Hua , Busalacchi Antonio J.
Published: October 2005

Simulations from a 49‐year, realistically forced numerical model experiment indicate that decadal variability of temperature and salinity along the equator originates from subsurface spiciness anomalies in the South Pacific. Through western boundary and interior pathways in the thermocline, the subsurface anomalies in the South Pacific are first transferred westward and then northward, eventually appearing along the equator. The large spiciness anomalies in the South Pacific are formed in the eastern subtropics where large unstable salinity gradients are present in conjunction with weak stratification and strong mixing during winters. Our analysis shows that positive anomalies are generated in late winter by diapycnal mixing across isopycnal surfaces that are not exposed to the surface, i.e., through the injection process, in agreement with Yeager and Large (2004). In addition, we show that spiciness anomalies can also be created along isopycnals that outcrop to the surface through the subduction process, although this process alone is not enough to explain a significant part of the decadal variability along the equator based upon an active tracer experiment. Both the injection and subduction processes are responsible for forming positive subsurface anomalies in the eastern subtropical South Pacific, while negative anomalies there can be generated by subduction of negative surface anomalies and accumulation via isopycnal advection.
Cloud heights from TOVS Path‐B: Evaluation using LITE observations and distributions of highest cloud layers
Authors: Stubenrauch Claudia J. , Eddounia Fadoua , Sauvage Laurent
Published: October 2005

Cloud height from the TIROS‐N Operational Vertical Sounder (TOVS) Path‐B climate data set has been evaluated by using vertical profiles of the backscattered radiation at 532 nm from quasi‐simultaneous Lidar In‐space Technology Experiment (LITE) observations. Two averaging methods for the LITE inversion have been studied. Because of the LITE noise level and the difficulty in determining the vertical structure of thick clouds, we have chosen to apply the inversion on the average backscatter signal of the LITE spots over regions of 1° latitude × 1° longitude, which is also the spatial resolution of the TOVS Path‐B data set. The cloud height determined by TOVS corresponds well in general to the height of the “apparent middle” of the cloud system with coincidences for 53% of TOVS Path‐B low‐level clouds within 1 km and for 49% of TOVS Path‐B high‐level clouds within 1.5 km. In addition, 22.5% of TOVS Path‐B low‐level clouds are covered by a very thin high cloud layer not detectable by TOVS. Comparing for these cases the TOVS cloud height with the second LITE cloud layer increases the overall agreement for low‐level clouds to about 64%. High‐level clouds appear more often in multilayer systems (about 75%) and are also vertically more extended. Differences in average cloud height of high‐level clouds appear only to be significant (13.3 km from LITE compared to 11.3 km from TOVS Path‐B) in the tropics with a large extent of laminar cirrus situated near the tropopause. The height of maximum backscatter of most thick clouds is several hundred meters above “apparent cloud midlevel,” whereas thin high‐level clouds with underlying lower clouds provide a backscatter signal nearer to apparent cloud midlevel. In the latter case, the retrieved TOVS Path‐B cloud height is on average 280 m underestimated. Pressure distributions of the highest cloud layer weighted by effective cloud amount confirmed that high clouds have the lowest pressure in the tropics because of a higher tropopause, and in these regions there are nearly no cloud systems with the highest cloud layer in the middle troposphere. The Southern Hemisphere midlatitudes are mostly covered by low‐level clouds. Seasonal differences in the Northern Hemisphere (midlatitudes, with more equally distributed cloud altitudes in winter) are mostly caused by changes over land.
Mount Gambier (38°S, 141°E) prototype VHF wind profiler
Authors: Reid I. M. , Holdsworth D. A. , Kovalam S. , Vincent R. A. , Stickland J.
Published: October 2005

The Mount Gambier wind profiling radar was installed in September 1997 and has operated almost continuously since the beginning of 1998. The site is at the Australian Commonwealth Bureau of Meteorology Mount Gambier Meteorological Office, close to the Mount Gambier airport. The radar was developed as a prototype operational profiler by the Atmospheric Physics Group at the University of Adelaide, in collaboration with the Australian Commonwealth Bureau of Meteorology. It was designed to operate as a spaced antenna radar, as a Doppler beam swinging radar, and as a hybrid Doppler interferometer. Here we present a summary of the operation of the system and a comparison with radiosonde observations concentrating on operation in the spaced antenna mode. The utility of the system and recommendations for the further development of similar systems are addressed.
Source and evolution of the marine aerosol—A new perspective
Authors: Leck Caroline , Bigg E. Keith
Published: October 2005

The “indirect effect of aerosols” refers to their ability to influence cloud radiative properties, and is considered to be one of the larger uncertainties in climate prediction. Oceans cover about 70% of the world's surface and the aerosols that they produce are therefore likely to represent an important part of the indirect effect. A description of the ultimate sources of all aerosol constituents and their susceptibility to climate change is then required in order to assess the potential of an aerosol‐cloud‐climate feedback. Here we argue that in the high Arctic in summer, cloud condensation nuclei (CCN) concentration is not determined by the oxidation products of dimethyl‐sulfide as has usually been assumed but by the concentration in the air of small insoluble organic particles derived from the surface microlayer of the ocean by bubble bursting, on which the acid gases condense. Examination of the aerosol over lower latitude oceans suggests that similar processes occur over all oceans.
Bias corrections of long‐term (1973–2004) daily precipitation data over the northern regions
Authors: Yang Daqing , Kane Douglas , Zhang Zhongping , Legates David , Goodison Barry
Published: October 2005

A consistent daily bias correction procedure was applied at 4802 stations over high latitude regions (North of 45°N) to quantify the precipitation gauge measurement biases of wind‐induced undercatch, wetting losses, and trace amount of precipitation for the last 30 years. These corrections have increased the gauge‐measured monthly precipitation significantly by up to 22 mm for winter months, and slightly by about 5 mm during summer season. Relatively, the correction factors (CF) are small in summer (10%), and very large in winter (80–120%) because of the increased effect of wind on gauge undercatch of snowfall. The CFs also vary over space particularly in snowfall season. Significant CF differences were found across the USA/Canada borders mainly due to differences in catch efficiency between the national gauges. Bias corrections generally enhance monthly precipitation trends by 5–20%. These results point to a need to review our current understanding of the Arctic fresh water budget and its change.
European temperature distribution changes in observations and climate change scenarios
Authors: Scherrer Simon C. , Appenzeller Christof , Liniger Mark A. , Schär Christoph
Published: October 2005

Changes in the distribution of seasonal surface temperature are investigated in central Europe using observations between 1961 and 2004 and a set of IPCC SRES A2 and B2 climate change simulations. A piecewise detrending methodology is used to distinguish between intrinsic and trend‐induced variability changes. Mean and interannual variability changes are standardized with the intrinsic variability of the respective dataset. Within this framework, the strongest temperature changes in mean since 1990 are found for the summer season, both in observations and climate models. Estimates for variability changes show a weak increase (decrease) in summer (winter), but these changes are not statistically significant at the 90% level. For the 21st century all climate scenario runs suggest large relative increases in mean for all seasons with maximum amplitude in summer. Although changes in relative variability vary substantially between the models, there is a tendency for increasing (decreasing) variability in future summers (winters).
A universal characteristic of type II radio bursts
Authors: Aguilar‐Rodriguez E. , Gopalswamy N. , MacDowall R. , Yashiro S. , Kaiser M. L.
Published: October 2005

We present a study on the spectral properties of interplanetary type II radio bursts observed by the Radio and Plasma Wave (WAVES) experiment on board the Wind spacecraft. We investigated the relative bandwidth of the type II radio bursts observed by WAVES from 1997 up to 2003. We obtained three sets of events, based on the frequency domain of occurrence: 109 events in the low‐frequency domain (30 KHz to 1000 kHz, detected by the RAD1 receiver), 216 events in the high‐frequency domain (1–14 MHz, observed by the RAD2 receiver), and 73 events that spanned both domains (RAD1 and RAD2). Statistical results show that the average bandwidth‐to‐frequency ratio (BFR) was 0.28 ± 0.15, 0.26 ± 0.16, and 0.32 ± 0.15 for RAD1, RAD2, and RAD1 + RAD2, respectively. We compared our results with those obtained for ISEE‐3 type II bursts and found a difference in the average BFR, which seems to be due to a selection effect. The BFR of the WAVES type II bursts is similar to that of metric type II bursts reported in published works. This suggests that the BFR is a universal characteristic, irrespective of the spectral domain. Finally, we also studied the BFR evolution with heliocentric distance using white‐light observation of the associated coronal mass ejections. We found that the BFR remains roughly constant in the SOHO/LASCO field of view (i.e., from 2.1 to 32 solar radii), while the bandwidth itself decreases.
Integrative Levels, the Brain, and the Emergence of Complex Behavior
Authors: Greenberg Gary , Partridge Ty , Weiss Emily , Haraway Maury M.
Published: October 2005

The aim of this article is to bring clarity and unification to the question of how certain complex behaviors, such as feeding, learning, language, culture, and neural complexity, are related. Three critical ideas—the organizing principle of integrative levels, the tendency for increased complexity with evolutionary change, and the contextual nature of behavioral events—are central to the discussion. A theoretical framework is presented that synthesizes existing knowledge in a meaningful way. Data are drawn from the behavioral, neuroanatomical, cognitive, and linguistic sciences and integrated within an organized and unified theoretical perspective referred to as developmental dynamic systems theory.
Own versus Other Standpoints in Self-Regulation: Developmental Antecedents and Functional Consequences
Authors: Moretti Marlene M. , Higgins E. Tory
Published: October 2005

An inner audience is an internal representation of others' values, goals, and standards for the self (other standpoint on self). It contrasts with an internal representation of one's own values, goals, and standards for the self (own standpoint on self). Using self-discrepancy theory ( E. T. Higgins, 1987) as a framework to integrate diverse psychological perspectives on this classic distinction, the authors consider the role of own versus other standpoints in self-regulation. They describe developmental shifts and socialization effects on the self-regulatory strength of own and other standpoints. Evidence that individual differences and sex differences in own versus other standpoints for self-regulation relate to different affective and interpersonal vulnerabilities is reviewed. The concepts of identification and introjection are empirically distinguished in a novel way, and therapeutic implications are discussed.
Reconceptualizing Learning
Authors: Howard Robert W.
Published: October 2005

“Learning” is a key psychological notion surrounded by some conceptual confusion. It is conceptualized in various different ways, it is notoriously difficult to define, and the notion and ways in which it is used sit uneasily with current conceptualizations of cognition. This article analyzes the concept of learning and the domain that it helps carve up to highlight its problems and then argues that learning is an inherently poor category that is best abandoned. Its use creates problems, separates research areas, and suggests poor questions. Its domain is better divided up with the notion of representation creation and alteration, which resolves various problems, simplifies the field, and better connects traditional work in learning theory with current work on cognition.
A Goal Systems–Self-Regulatory Perspective on Personality, Psychopathology, and Change
Authors: Karoly Paul
Published: October 2005

A motivational framework is presented linking personal goals and self-regulatory functions to normal personality, psychopathology, and the processes of change. First, the utility of goals as a “final common analytic pathway” or integrative unit is considered. Next, the premises of an emerging, goal-centered conception of adaptive functioning are discussed as a prelude to the author's outlining of a multidimensional working model of “goal systems.” Reactive depression is reconceptualized in terms of specific self-regulatory dysfunctions under the influence of goal systems to illustrate how dysfunctional goal systems can serve as the central organizing component of psychopathology. A set of 10 propositions pinpoints goal-based sources of vulnerability to self-regulatory dysfunction in depression. A set of 5 propositions details the potential goal-based sources of maintenance of self-regulatory deficits. Finally, 14 theory-based principles of psychotherapeutic change are proposed.
Control and Efficacy as Interdisciplinary Bridges
Authors: Haidt Jonathan , Rodin Judith
Published: October 2005

Control and efficacy are ideally suited as “bridges” or linking constructs for social scientists working at different levels of analysis. Control and efficacy depend on the fit between individuals and the social systems in which they are embedded, and control and efficacy have measurable effects on neurotransmitter levels and endocrine responses. This article presents an interdisciplinary perspective on control and efficacy. The authors survey the history of control-related constructs in psychology, from their roots in animal learning to the present cognitive focus on beliefs about control. They then point out connections “up” to the sociological level and “down” to the physiological level. They propose a taxonomy of 6 useful constructs organized into 3 perspectives: motivational, cognitive, and systemic. Such a multilevel, multidisciplinary approach may be particularly useful for approaching large real-world problems such as improving schools or neighborhoods.
Methodological and Theoretical Orientation and the Long-Term Disciplinary Impact of 54 Eminent Psychologists
Authors: Simonton Dean Keith
Published: October 2005

The long-term influence of 54 highly eminent psychologists was hypothesized to be a function of their methodological and theoretical orientation. Individual differences in impact were gauged via the Social Sciences Citation Index for 1976–1980 and 1986–1990. Orientation was assessed along 6 dimensions: objectivistic versus subjectivistic, quantitative versus qualitative, elementaristic versus holistic, impersonal versus personal, static versus dynamic, and exogenist versus endogenist ( R. W. Coan, 1979 ). Correlation and regression analyses revealed that long-term influence could be predicted by both method and theory measures. Especially significant was the curvilinear backward-J curve between total citations and a general factor defined by all 6 bipolar dimensions. The most influential psychologists tend to take extreme positions on the controversies that have characterized the history of psychology.
Illusory Correlations: A Simple Associative Algorithm Provides a Convergent Account of Seemingly Divergent Paradigms
Authors: Fiedler Klaus
Published: October 2005

Subjective correlations that exaggerate objectively presented contingencies are usually referred to as illusory correlations. An empirical review reveals 3 major paradigms of illusory correlations, drawing on 2 prominent but conflicting gestalt principles, congruency and distinctiveness. Congruency accounts for expectancy-based illusory correlations, whereas distinctiveness is relevant to illusions resulting from the asymmetry of positive and negative attributes and from infrequency. The congruency principle implies a processing advantage for expected stimuli, whereas distinctiveness assumes enhanced processing of unexpected events. This apparent conflict is resolved, and an integrative account is offered within a simple connectionist framework (BIAS) of correlation assessment. The basic algorithm is outlined, empirical findings are simulated, new theoretical distinctions are introduced, and analogies to related paradigms are explained.
Implicit and Explicit Components of Prejudice
Authors: Brauer Markus , Wasel Wolfgang , Niedenthal Paula
Published: October 2005

Research on implicit and explicit prejudice has treated implicit prejudice as a unitary construct characterized by automatic access to negative concepts. The present article makes the case that tasks purported to measure implicit prejudice actually assess 2 different processes. Some assess the extent to which prejudice is activated automatically on the perception of a member of the target group. Other implicit tasks assess the extent to which prejudice is automatically applied in judgment. In the reported study, participants completed 4 implicit and 2 explicit measures of prejudice against women. Factor analysis yielded a 3-factor solution. The solution provides support for the distinction between explicit prejudice and 2 types of implicit prejudice corresponding to automatic activation and automatic application of prejudice. Prejudice appears to be a multifaceted construct, different aspects of which are measured by different tasks.
The Internal Working Models Concept: What do we Really know about the Self in Relation to Others?
Authors: Pietromonaco Paula R. , Barrett Lisa Feldman
Published: October 2005

The internal working models concept is the foundation for understanding how attachment processes operate in adult relationships, yet many questions exist about the precise nature and structure of working models. To clarify the working models concept, the authors evaluate the empirical evidence relevant to the content, structure, operation, and stability of working models in adult relationships. They also identify 4 theoretical issues that are critical for clarifying the properties of working models. These issues focus on the central role of affect and goals in working models, the degree to which working models are individual difference or relational variables, and the definition of attachment relationships and felt security in adulthood.
Toward a Neurobiology of Attachment
Authors: Insel Thomas R.
Published: October 2005

Although much has been written about the psychological aspects of attachment, still relatively little is known about how the brain organizes this complex behavior or how attachment alters brain organization. Recent research has suggested that neuropeptides may be important as neural modulators for several complex behaviors. This review examines the research on one specific neuropeptide, oxytocin, to describe approaches to the neurobiology of attachment at several levels, including molecular, cellular, and whole animal studies. A key to understanding oxytocin's role in behavior is a careful analysis of the pattern of oxytocin receptors in the brain. The available data support the hypothesis that oxytocin is critical for maternal behavior and pair-bond formation in select nonhuman animals. Humans have oxytocin and brain oxytocin receptors, but the role of this neuropeptide system in human attachment remains highly speculative.
Reaction-induced phase separation of pseudo-interpenetrating polymer networks in polydisperse polymer blends: A simulation study
Authors: Henderson Ian C. , Clarke Nigel
Published: October 2005

We develop a minimal model for the process of reaction-induced phase separation in a polydisperse polymer blend. During the reaction, one component undergoes polymerization, leading to phase separation via spinodal decomposition. The effect that changing the final degree of polymerization has on the phase-separation process is studied. Finally an elastic energy term is included mimicking the cross-linking process and the generation of a semi-interpenetrating polymer network. We show that the scaling of the dominant lengthscale with time varies according to the reaction conditions.
Nonideality of polymer solutions in the pore and concentration-dependent partitioning
Authors: Zitserman Vladimir Yu. , Berezhkovskii Alexander M. , Parsegian V. Adrian , Bezrukov Sergey M.
Published: October 2005

To explain the concentration dependence of the partition coefficient of polyethylene glycol into α-hemolysin channels, weak nonideality of the polymer solution in the pore is taken into account. Polymer molecules in the pore form cigars with higher intramolecular monomer density and, therefore, higher overlap volume fraction.
Constant-pressure simulations with dissipative particle dynamics
Authors: Trofimov S. Y. , Nies E. L. F. , Michels M. A. J.
Published: October 2005

Dissipative particle dynamics (DPD) is a mesoscopic simulation method for studying hydrodynamic behavior of complex fluids. Ideally, a mesoscopic model should correctly represent the thermodynamic and hydrodynamic properties of a real system beyond certain length and time scales. Traditionally defined DPD quite successfully mimics hydrodynamics but is not flexible enough to accurately describe the thermodynamics of a real system. The so-called multibody DPD (MDPD) is a pragmatic extension of the classical DPD that allows one to prescribe the thermodynamic behavior of a system with only a small performance impact. In an earlier paper [S. Y. Trofimov, E. L. F. Nies, and M. A. J. Michels, J. Chem. Phys. 117, 9383 (2002)] we much improved the accuracy of the MDPD model for strongly nonideal systems, which are of most practical interest. The ability to correctly reproduce the equation of state of realistic systems in turn makes simulations at constant pressure sensible and useful. This situation of constant-pressure conditions is very common in experimental studies of (soft) condensed matter but has so far remained unexplored with the traditional DPD. Here, as a proof of concept, we integrate a modified version of the Andersen barostat into our improved MDPD model and make an evaluation of the performance of the new model on a set of single- and multicomponent systems. The modification of the barostat suppresses the “unphysical” volume oscillations after a sudden pressure change and simplifies the equilibration of the system.
A kinetic model for the oxidation of silicon germanium alloys
Authors: Rabie Mohamed A. , Haddara Yaser M. , Carette Jacques
Published: October 2005

We propose a complete model for the oxidation of silicon germanium. Our model includes the participation of both silicon and germanium atoms in the oxidation process and the replacement by silicon of germanium in mixed oxides. Our model is capable of predicting, as a function of time, the oxide thickness, the profile of the silicon in the underlying alloy, and the profile of germanium in the oxide. The parameters of the model vary with temperature, alloy composition, and oxidizing ambient. The model shows excellent agreement with published results, with model parameters following trends consistent with the physical phenomena hypothesized. The presence of germanium catalyzes both the silicon and the germanium oxidation rates, and all reaction rates increase with increasing temperature. The resulting effective oxidation rate is enhanced, with respect to the oxidation of pure silicon, at all germanium concentrations. Mixed oxides form only in the case of high germanium concentrations, but at high temperatures the rapid growth of a thick oxide results in a slowing of oxidant diffusion, and the oxide composition switches back to a pure silicon oxide.
On the bicoherence analysis of plasma turbulence
Authors: Itoh K. , Nagashima Y. , Itoh S.-I. , Diamond P. H. , Fujisawa A. , Yagi M. , Fukuyama A.
Published: October 2005

The bicoherence of fluctuations in a system of drift waves and zonal flows is discussed. In strong drift-wave turbulence, where broadband fluctuations are excited, the bicoherence is examined. A Langevin equation formalism of turbulent interactions allows us to relate the bicoherence coefficient to the projection of nonlinear force onto the test mode. The dependence of the summed bicoherence on the amplitude of zonal flows is clarified. The importance of observing biphase is also stressed. The results provide a basis for measurement of nonlinear interaction in a system of drift waves and zonal flow.
Radio-frequency plasma functionalization of carbon nanotubes surface O2, NH3, and CF4 treatments
Authors: Felten A. , Bittencourt C. , Pireaux J. J. , Van Lier G. , Charlier J. C.
Published: October 2005

Inductive coupled rf-plasma at 13.56 MHz was used to modify multiwalled carbon nanotubes (MWCNTs). This technique can be easily used to tailor the chemical composition of carbon nanotubes by attaching a wide variety of functional groups at their surface: oxygen-, nitrogen-, and fluorine-containing groups have been grafted. The influence of various plasma conditions (power, type of gas, treatment time, pressure, position of the CNT sample inside the chamber) on the functionalization of the MWCNT surface was analyzed by x-ray photoelectron spectroscopy. The results show that for too high oxygen plasma power, chemical etching occurs at the surface of the CNT, thus destroying its structure. On the other hand, for optimal values of the plasma parameters, functional groups (hydroxide, carbonyl, carboxyl, amine, fluorine, etc.) were found to bond to the CNT surface, suggesting that both the concentration and type of the functional groups are in close connection with the plasma conditions. These results were compared to interaction energies predicted by ab initio calculations for different functional groups under consideration, showing that functionalization by oxygen plasma produces mainly functional groups with lower interaction energy.
Conically shaped single-crystalline diamond backing plates for a diamond anvil cell
Authors: Krauss G. , Reifler H. , Steurer W.
Published: October 2005

Based on computer-aided design (CAD) and finite-element calculations (FEM), single-crystalline diamond backing plates were tailored as a replacement of beryllium for high-pressure diamond anvil cells with a focus on in-house single-crystal experiments. Although the modified cell has an opening angle of 90°, a very homogeneous stress distribution all over the backing plate was realized to avoid failure. The conically shaped backing plates work well in the targeted pressure range up to ∼10GPa using diamond anvils with 0.6 mm culet diameter. This is shown by a compressibility study of the complex intermetallic alloy Mg2Co3Sn10.15 up to 9.69 GPa. The influence of simultaneous diffraction phenomena in the diamonds (diamond dips) is illustrated by single-counter and area-detector measurements using standard laboratory equipment.
Carbon nanotube quantum dots fabricated on a GaAs∕AlGaAs two-dimensional electron gas substrate
Authors: Tsukamoto T. , Moriyama S. , Tsuya D. , Suzuki M. , Yamaguchi T. , Aoyagi Y. , Ishibashi K.
Published: October 2005

Single-wall carbon nanotube (SWCNT) quantum dots have been fabricated on a GaAs∕AlGaAs two-dimensional electron gas (2DEG) substrate, and the single electron transport measurements have been carried out at 2.8 K and 22 mK with the 2DEG used as a gate. It was demonstrated that the gating by the 2DEG could be switched on and off by controlling a quantum point contact fabricated between the dot and the Ohmic contact to the 2DEG gate. The unique combination of the SWCNT dot and the 2DEG may open a door to realize flexible hybrid devices.
Light-output enhancement of GaN-based light-emitting diodes by using hole-patterned transparent indium tin oxide electrodes
Authors: Leem Dong-Seok , Cho Jaehee , Sone Cheolsoo , Park Yongjo , Seong Tae-Yeon
Published: October 2005

We have demonstrated the improvement of the light-output power of GaN-based light-emitting diodes (LEDs) using hole-patterned indium tin oxide (ITO) p-type electrodes. Hole patterns were defined by a laser holographic lithography combined with a postlithography deposition process. It is shown that near-UV LEDs made with the patterned ITO with a hole period of 710nm and a size of 320nm give 23% and 67% higher light-output power (at 20mA) than those of LEDs with unpatterned ITO and Ni∕Au contacts, respectively. It is further shown that the reduction of the hole period results in an additional improvement of light-output power.
Density limit for electron plasmas confined by magnetic surfaces
Authors: Boozer Allen H.
Published: October 2005

The density limit for electron plasmas confined by toroidal magnetic surfaces is investigated. In a cylinder, the well-known limit is the Brillouin density, nB≡ϵ0B2∕2me. In an axisymmetric torus, the confining region shifts outward in major radius, and this shift is shown to equal half the plasma radius when n∕nB≈ι2a∕R0, where ι=1∕q is the rotational transform of the magnetic field and a∕R0 is the inverse aspect ratio of the torus. In a nonaxisymmetric torus, electron confinement is found to be lost due to stochasticity effects when n∕nB≈(ι2∕8M2)(a∕R0)2∕δMN. The asymmetry amplitudes δMN are the fractional variations in n∕B2 on a magnetic surface in the poloidal mode number M and the toroidal mode number N≈ιM.
Measurement of the magnetoelectric coefficient using a scanning evanescent microwave microscope
Authors: Gao Chen , Hu Bo , Li Xuefei , Liu Chihui , Murakami M. , Chang K.-S. , Long C. J. , Wuttig M. , Takeuchi I.
Published: October 2005

A quantitative magnetoelectric coefficient measurement method was developed based on scanning evanescent microwave microscopy. This unique technique does not require electrodes and has advantages that it has a high spatial resolution and can simultaneously measure other related properties such as the nonlinear dielectric constant. We have demonstrated that this technique can detect the magnetoelectric coefficient of thin film samples as low as 10mV∕cmOe.
Quantitative electrostatic force microscopy on heterogeneous nanoscale samples
Authors: Palacios-Lidón E. , Abellán J. , Colchero J. , Munuera C. , Ocal C.
Published: October 2005

Locally resolved electrostatic force spectroscopy is combined with Kelvin force microscopy to compare the results obtained using either the force or the frequency as signal source for tip-sample interaction. A two-component locally heterogeneous sample—islands of octadecanethiol molecules self-assembled on Au(111)—is used as a nanometer scale model system. On this kind of sample, electrostatic force spectroscopy as well as Kelvin force microscopy clearly demonstrate that local and quantitative electrostatic force microscopy has to be implemented with the frequency as the signal source.
Modeling of heterogeneous precipitation of iron in silicon
Authors: Haarahiltunen A. , Väinölä H. , Anttila O. , Saarnilehto E. , Yli-Koski M. , Storgårds J. , Sinkkonen J.
Published: October 2005

A model is presented for the growth and dissolution of iron precipitates at oxygen-related defects in silicon during thermal processing. The heterogeneous nucleation of iron is taken into account by special growth and dissolution rates, which are inserted into a set of modified chemical rate equations. This approach allows us to calculate the size distribution of iron precipitates and the residual iron concentration. By comparing the simulated results with experimental ones, it is proven that this model can be used to estimate the internal gettering efficiency of iron under a variety of processing conditions.
Role of locked mode in the effectiveness of pulsed poloidal current drive regime in the reversed-field pinch
Authors: Frassinetti L. , Yagi Y. , Koguchi H. , Shimada T. , Hirano Y. , Sakakita H.
Published: October 2005

The close relationship between the locked mode (LM) and pulsed poloidal current drive (PPCD) regime in a reversed-field pinch device is described. If the modes lock close to the shell gap then the LM is enhanced and there is a high probability that the PPCD will not improve plasma performance. The physical reason will be discussed. If the position of the locked mode is far from the shell gap then the PPCD is effective with a high probability. LM energy is reduced and the more the LM energy decreases, the better the plasma performance.
Requirement of myocardin-related transcription factor-B for remodeling of branchial arch arteries and smooth muscle differentiation
Authors: Oh Jiyeon , Richardson James A. , Olson Eric N.
Published: October 2005

Myocardin and the myocardin-related transcription factors (MRTFs) A and B act as coactivators for serum response factor, which plays a key role in cardiovascular development. To determine the functions of MRTF-B
in vivo
, we generated
MRTF-B
mutant mice by targeted inactivation of the
MRTF-B
gene. We show that mice homozygous for an
MRTF-B
loss-of-function mutation die during mid-gestation from a spectrum of cardiovascular defects that includes abnormal patterning of the branchial arch arteries, double-outlet right ventricle, ventricular septal defects, and thin-walled myocardium. These abnormalities are accompanied by a failure in differentiation of smooth muscle cells within the branchial arch arteries, which are derived from the neural crest. The phenotype of
MRTF-B
mutant mice is distinct from that of mice lacking myocardin, revealing unique roles for these serum response factor coactivators in the development of different subsets of smooth muscle cells
in vivo
.
OxfordGrid: a web interface for pairwise comparative map views
Authors: Yang Hongyu , Gingle Alan R.
Published: October 2005

Summary: OxfordGrid is a web application and database schema for storing and interactively displaying genetic map data in a comparative, dot-plot, fashion. Its display is composed of a matrix of cells, each representing a pairwise comparison of mapped probe data for two linkage groups or chromosomes. These are arranged along the axes with one forming grid columns and the other grid rows with the degree and pattern of synteny/colinearity between the two linkage groups manifested in the cell's dot density and structure. A mouse click over the selected grid cell launches an image map-based display for the selected cell. Both individual and linear groups of mapped probes can be selected and displayed. Also, configurable links can be used to access other web resources for mapped probe information.

Availability: OxfordGrid is implemented in C#/ASP.NET and the package, including MySQL schema creation scripts, is available at

Contact:  agingle@uga.edu
Pcons5: combining consensus, structural evaluation and fold recognition scores
Authors: Wallner Björn , Elofsson Arne
Published: October 2005

Motivation: The success of the consensus approach to the protein structure prediction problem has led to development of several different consensus methods. Most of them only rely on a structural comparison of a number of different models. However, there are other types of information that might be useful such as the score from the server and structural evaluation.

Results: Pcons5 is a new and improved version of the consensus predictor Pcons. Pcons5 integrates information from three different sources: the consensus analysis, structural evaluation and the score from the fold recognition servers. We show that Pcons5 is better than the previous version of Pcons and that it performs better than using only the consensus analysis. In addition, we also present a version of Pmodeller based on Pcons5, which performs significantly better than Pcons5.

Availability: Pcons5 is the first Pcons version available as a standalone program from . It should be easy to implement in local meta-servers.

Contact:  bjorn@sbc.su.se
Significant changes in the bacterioplankton community structure of a maritime Antarctic freshwater lake following nutrient enrichment
Authors: Pearce David A. , van der Gast Christopher J. , Woodward Kelly , Newsham Kevin K.
Published: October 2005

Nutrient enrichment is known to increase bacterioplankton population density in a variety of Antarctic freshwater lakes. However, relatively little is known about the associated changes in species composition. In this study, the bacterioplankton community composition of one such lake was studied following natural nutrient enrichment to investigate the resistance of the system to environmental change. Heywood Lake is an enriched freshwater maritime Antarctic lake, with nitrogen and phosphorus concentrations significantly higher than its more oligotrophic neighbours (by at least an order of magnitude). This major change in lake chemistry has occurred following large increases in the fur seal population over the last 30 years. Using analysis of 16S rRNA gene fragments, fatty acid methyl ester analysis, denaturing gradient gel electrophoresis and fluorescencein situhybridization, significant changes are reported in lake microbiology which have resulted in a distinct bacterioplankton community. In comparison to its more oligotrophic neighbours, nutrient-enriched Heywood Lake has a high bacterioplankton population density, reduced species richness and an increasing evenness among key groups. Only 42·3 % of the clones found with ≥97 % similarity to a named genus were also present in adjacent oligotrophic lakes, including three of the dominant groups. Critically, there was an apparent shift in dominance with trophic status (from theβ-Proteobacteriato theActinobacteria). Other key observations included the absence of a dominant group ofCyanobacteriaand the presence of marine bacteria. The significant impact of natural nutrient enrichment on the microbiology of Heywood Lake, therefore, suggests that low-temperature oligotrophic freshwater lake systems might have low resistance to environmental change.
Continuous culture – making a comeback?
Authors: Hoskisson Paul A. , Hobbs Glyn
Published: October 2005

The heyday of continuous culture was in the 1960s, when its versatility and reproducibility were used to address fundamental problems in diverse microbiological fields such as biochemistry, ecology, genetics and physiology. The advent of molecular genetics in the 1970s and 1980s led to a decline in the popularity of continuous culture as a standard laboratory tool. The current trend of studying global proteomics, transcriptomics and metabolomics requires reproducible, reliable and biologically homogeneous datasets with which to approach a given problem. The use of continuous culture techniques can aid the acquisition of such data, and continuous cultures offer advantages over biologically heterogeneous batch cultures, where secondary growth and stress effects can often mask subtle physiological differences and trends. This review is intended to remind microbiologists of the value of continuous cultivation in a wide range of biological investigations, and describes some advantages and recent advances in applications of continuous culture in post-genomic studies.
N-Acylhomoserine lactone quorum-sensing molecules are modified and degraded by Rhodococcus erythropolis W2 by both amidolytic and novel oxidoreductase activities
Authors: Uroz Stéphane , Chhabra Siri Ram , Cámara Miguel , Williams Paul , Oger Phil , Dessaux Yves
Published: October 2005

The Rhodococcus erythropolis strain W2 has been shown previously to degrade the N-acylhomoserine lactone (AHL) quorum-sensing signal molecule N-hexanoyl-l-homoserine lactone, produced by other bacteria. Data presented here indicate that this Gram-positive bacterium is also capable of using various AHLs as the sole carbon and energy source. The enzymic activities responsible for AHL inactivation were investigated in R. erythropolis cell extracts and in whole cells. R. erythropolis cells rapidly degraded AHLs with 3-oxo substituents but exhibited relatively poor activity against the corresponding unsubstituted AHLs. Investigation of the mechanism(s) by which R. erythropolis cells degraded AHLs revealed that 3-oxo compounds with N-acyl side chains ranging from C8 to C14 were initially converted to their corresponding 3-hydroxy derivatives. This oxidoreductase activity was not specific to 3-oxo-AHLs but also allowed the reduction of compounds such as N-(3-oxo-6-phenylhexanoyl)homoserine lactone (which contains an aromatic acyl chain substituent) and 3-oxododecanamide (which lacks the homoserine lactone ring). It also reduced both the d- and l-isomers of n-(3-oxododecanoyl)-l-homoserine lactone. A second AHL-degrading activity was observed when R. erythropolis cell extracts were incubated with N-(3-oxodecanoyl)-l-homoserine lactone (3O,C10-HSL). This activity was both temperature- and pH-dependent and was characterized as an amidolytic activity by HPLC analysis of the reaction mixture treated with dansyl chloride. This revealed the accumulation of dansylated homoserine lactone, indicating that the 3O,C10-HSL amide had been cleaved to yield homoserine lactone. R. erythropolis is therefore capable of modifying and degrading AHL signal molecules through both oxidoreductase and amidolytic activities.
Independent regulation of H-NS-mediated silencing of the bgl operon at two levels: upstream by BglJ and LeuO and downstream by DnaKJ
Authors: Madhusudan S. , Paukner Andreas , Klingen Yvonne , Schnetz Karin
Published: October 2005

Silencing of theEscherichia coli bgloperon by the histone-like nucleoid-structuring protein H-NS occurs at two levels. Binding of H-NS upstream of the promoter represses transcription initiation, whilst binding within the coding region is also proposed to repress transcription elongation. The latter, downstream level of repression is counteracted by the protease Lon and, thus, silencing of thebgloperon is more effective inlonmutants. Transposon-mutagenesis screens for suppression of thislonphenotype onbglwere performed and insertion mutations disruptingrpoSandcrlwere obtained, as well as mutations mapping upstream of the open reading frames ofbglJ,leuOanddnaK. InrpoSandcrlmutants,bglpromoter activity is known to be higher. Likewise, as shown here,bglpromoter activity is increased in thebglJandleuOmutants, which express BglJ and LeuO constitutively. However, BglJ and LeuO have no impact on downstream repression. AdnaKJmutant was isolated for the first time in the context of thebgloperon. The mutant expresses lower levels of DnaK than the wild-type. Interestingly, in thisdnaKJ : : miniTn10mutant, downstream repression ofbglby H-NS is less effective, whilst upstream repression by H-NS remains unaffected. Together, the data show that the two levels ofbglsilencing by H-NS are regulated independently.
Allyl alcohol and garlic (Allium sativum) extract produce oxidative stress in Candida albicans
Authors: Lemar Katey M. , Passa Ourania , Aon Miguel A. , Cortassa Sonia , Müller Carsten T. , Plummer Sue , O'Rourke Brian , Lloyd David
Published: October 2005

Both the growth and respiration ofCandida albicansare sensitive to extracts ofAllium sativumand investigations into the anticandidal activities are now focussing on the purified constituents to determine the targets of inhibition. Of particular interest is allyl alcohol (AA), a metabolic product that accumulates after trituration of garlic cloves. Putative targets for AA were investigated by monitoring changes in intracellular responses after exposure ofC. albicanscells to AA or a commercially available garlic extract. Two-photon laser scanning microscopy and other techniques were used. Changes typical of oxidative stress – NADH oxidation and glutathione depletion, and increased reactive oxygen species – were observed microscopically and by flow cytometry. Known targets for AA are alcohol dehydrogenases Adh1 and 2 (in the cytosol) and Adh3 (mitochondrial), although the significant decrease in NAD(P)H after addition of AA is indicative of another mechanism of action.