bluuebunny/crossref_metadata_2025 huggingface dataset:
Psychotherapie bei Alzheimerpatienten: Eine neuropsychologische Aufgabe
Authors: Thöne-Otto Angelika I.T.
Published: June 2009

Kognitive, emotionale und behaviorale Veränderungen sind bei kaum einer Krankheit so sehr verwoben wie bei der Alzheimererkrankung. Dies ist auf die anfänglich zwar akzentuierten im weiteren Verlauf jedoch ubiquitäre Neurodegeneration zurückzuführen. In dieser Komplexität fällt die psychotherapeutische Behandlung von Alzheimerpatienten in die Kernkompetenz der Neuropsychologie. Am Beispiel der Therapie von Anosognosie, Apathie / Depression und Amnesie wird erläutert, wie eine integrative Behandlung, also die gleichzeitige Berücksichtigung affektiver und kognitiver Einflussfaktoren sowie der Einbezug der Angehörigen realisiert werden kann. Es werden Entscheidungshilfen für den Umgang mit verschiedenen Schweregraden der Anosognosie vermittelt. Aktivitätsaufbau wird als zentrale Möglichkeit im Umgang mit Depression und Apathie vorgestellt. Schließlich werden Methoden zur Vermittlung von domänenspezifischem Wissen und die zentrale Ressource des weitgehend erhaltenen prozeduralen Gedächtnisses in der Kompensation von deklarativen Gedächtnisstörungen beschrieben. Biografiearbeit wird als Chance im Umgang mit einem zunehmenden Identitätsverlust aufgrund episodischer Altgedächtnisstörungen vorgestellt. Die Neuropsychologische Therapie der Alzheimererkrankung steht noch am Beginn. Sie wird erfolgreich sein, wenn es gelingt, die verschiedenen Dimensionen der Erkrankung zu integrieren.
Bad Odors Stick Better Than Good Ones
Authors: Larsson Maria , Öberg-Blåvarg Christina , Jönsson Fredrik U.
Published: June 2009

The influences of perceived odor qualities on the retention of olfactory information across the adult lifespan were examined. Young (19–36 years), young-old (60–74 years), and old (75–91 years) adults (n = 202) rated a set of unfamiliar odors across a series of perceptual dimensions (i.e., pleasantness, intensity, and irritability) at encoding. The overall results indicated that memory for unpleasant olfactory information was better than that for pleasant odors across the lifespan. Also, participants showed better retention for odors perceived with high intensity and irritability than for odors rated with low or medium scores. Interestingly, the old adults showed selective beneficial memory effects for odors rated as highly irritable. To the extent that perceptions of high irritability reflect an activation of the trigeminal sensory system, this finding suggests that older adults may use trigeminal components in odor information to compensate for age-related impairments in olfactory memory.
Blocking of Conditioned Inhibition in Human Causal Learning
Authors: Lotz Anja , Vervliet Bram , Lachnit Harald
Published: June 2009

Compared to blocking of conditioned excitation, which is one of the most investigated cue competition phenomena, blocking of conditioned inhibition has more or less been neglected in conditioning research. We conducted a human causal learning study and found evidence for blocking of conditioned inhibition. The results favor the view that inhibition is the symmetrical opposite of excitation, underlying the same general principles.
Olfactory Imagery and Repetition Priming
Authors: Tomiczek Caroline , Stevenson Richard J.
Published: June 2009

This study examined the impact of odor naming and imagery ability on the capacity of female participants to form odor images, as indexed by a novel olfactory repetition priming task. Experiment 1 involved three conditions – olfactory and visual imagery priming, and a no-prime control. Odor imagery priming was only obtained in good odor namers. Experiment 2 used the same conditions, but altered the nature of the hit-rate trials to test how odor imagery might facilitate performance in good odor namers. Odor imagery priming was again obtained only in good odor namers and this effect appeared to result from generic activation of olfactory processing caused by trying to imagine a smell. Experiment 3 examined whether this latter effect might be generated semantically, but no evidence for this was obtained. Together, these findings suggest that trying to form an odor image can facilitate performance by producing a generic state of activation, which only benefits existing odor-name associations. While this effect is mediated via perceptual processes it may occur independently of a conscious image.
Geometric, Kinetic-Kinematic, and Intentional Constraints Influence Willingness to Pass Under a Barrier
Authors: Wagman Jeffrey B. , Malek Eric A.
Published: June 2009

Completing a goal directed behavior in a safe and efficient manner requires that a perceiver-actor is sensitive to the various constraints on performing that behavior and adjust his or her movements accordingly. When attempting to pass under a barrier, people adjust their ducking behavior based on the likelihood and potential costs of a collision ( van der Meer, 1997 ). In three experiments, we investigated whether participants are sensitive to geometric (standing height), kinetic-kinematic (anticipated movement speed), and intentional (material properties of the barrier) constraints on passing under a barrier even before attempting to perform this behavior. Although Experiment 1 failed to show that anticipated movement speed influenced perception of whether a barrier could be passed under, Experiment 2 found that this factor influences willingness to attempt the behavior. Experiments 3a and 3b found that the material properties of the barrier itself also influence willingness to attempt the behavior. Together, the results highlight the contribution of geometric, kinetic-kinematic, and intentional constraints to perception.
Subliminal Number Priming Within and Across the Visual and Auditory Modalities
Authors: Kouider Sid , Dehaene Stanislas
Published: June 2009

Whether masked number priming involves a low-level sensorimotor route or an amodal semantic level of processing remains highly debated. Several alternative interpretations have been put forward, proposing either that masked number priming is solely a byproduct of practice with numbers, or that stimulus awareness was underestimated. In a series of four experiments, we studied whether repetition and congruity priming for numbers reliably extend to novel (i.e., unpracticed) stimuli and whether priming transfers from a visual prime to an auditory target, even when carefully controlling for stimulus awareness. While we consistently observed cross-modal priming, the generalization to novel stimuli was weaker and reached significance only when considering the whole set of experiments. We conclude that number priming does involve an amodal, semantic level of processing, but is also modulated by task settings.
Fast and Fragile
Authors: Deutsch Roland , Kordts-Freudinger Robert , Gawronski Bertram , Strack Fritz
Published: June 2009

Numerous studies suggest that processing verbal materials containing negations slows down cognition and makes it more error-prone. This suggests that processing negations affords relatively nonautomatic processes. The present research studied the role of two automaticity features (processing speed and resource dependency) for negation processing. In three experiments, we tested the impact of verbal negations on affective priming effects in the Affect Misattribution Paradigm. Going beyond previous work, the results indicate that negations can be processed unintentionally and quickly (Experiments 1 and 2). In Experiment 3, negations failed to qualify affective priming effects when participants’ working memory was taxed by memorizing an eight-digit number. In sum, the experiments suggest that negations can be processed unintentionally, very quickly, but that they rely on working-memory resources.
Characterizing uncertainty in modeling primary terrestrial ecosystem processes
Authors: Arora V. K. , Matthews H. D.
Published: June 2009

The simulation results from models participating in the Coupled Climate Carbon Cycle Model Intercomparison Project (C4MIP) highlight the role of positive carbon‐climate feedback in accelerating growth of atmospheric CO2. The large range among models in the strength of this feedback indicates the uncertainty in our understanding of the response of the land and the oceans to continued climate warming and increasing CO2. Most of this uncertainty is associated with the response of terrestrial ecosystems to changes in climate and atmospheric CO2. The reasons for differences between models' responses to transient climate and CO2 forcing are not easily identified because of their complex parameterizations and spatially distributed processes. In this paper, we show that a simple box model can reasonably reproduce the globally averaged primary land‐atmosphere CO2 fluxes and carbon pools of two complex terrestrial ecosystem models (TEMs) over a range of emission scenarios. The parameters of the box model are calculated by fitting the box model to each TEM's response to transient climate and CO2 forcing. This approach is also applied to terrestrial carbon cycle components of carbon‐climate models participating in the C4MIP study. The resulting set of parameter values based on a common box model structure yields a wide range of parameter values, which suggests an absence of clear consensus in modeling primary terrestrial ecosystem processes and provides some insight into the reasons for divergent responses of terrestrial carbon cycle components.
A novel metric for coronal MHD models
Authors: Schmit D. J. , Gibson S. , de Toma G. , Wiltberger M. , Hughes W. J. , Spence H. , Riley P. , Linker J. A. , Mikic Z.
Published: June 2009

In the interest of quantitatively assessing the capabilities of coronal MHD models, we have developed a metric that compares the structures of the white light corona observed with SOHO LASCO C2 to model predictions. The MAS model is compared to C2 observations from two Carrington rotations during solar cycle 23, CR1913 and CR1984, which were near the minimum and maximum of solar activity, respectively, for three radial heights, 2.5 R⊙, 3.0 R⊙, and 4.5 R⊙. In addition to simulated polarization brightness images, we create a synthetic image based on the field topology along the line of sight in the model. This open‐closed brightness is also compared to LASCO C2 after renormalization. In general, the model's magnetic structure is a closer match to observed coronal structures than the model's density structure. This is expected from the simplified energy equations used in current global corona MHD models.
Interannual spring bloom variability and Ekman pumping in the coastal Gulf of Alaska
Authors: Fiechter Jerome , Moore Andrew M.
Published: June 2009

A lower trophic level ecosystem model is coupled to a three‐dimensional coastal ocean circulation model for the northwestern coastal Gulf of Alaska (CGOA) to investigate regional ecosystem dynamics on seasonal and interannual timescales. By including explicit growth limitation by light, nitrate, ammonium, silicic acid, and iron, the ecosystem model provides a comprehensive framework to investigate the combined role of macronutrients and micronutrients in shaping phytoplankton community structure. On the basis of comparisons with available in situ and remotely sensed observations for 1998 through 2002, the model reproduces the dominant modes of variability associated with the northwestern CGOA ecosystem dynamics. An empirical orthogonal function (EOF) analysis of biological and surface forcing fields suggests that, for the 5‐year period, interannual variability in peak chlorophyll concentrations during the spring bloom is related to interannual variability in the wind stress curl over the northern CGOA during the previous winter. Positive wind stress curl anomalies during winter result in enhanced Ekman pumping and, thus, nutrient upwelling on the shelf and at the shelfbreak. Since phytoplankton growth is severely light‐limited when Ekman pumping occurs, nutrient upwelling associated with the wind stress curl acts as a priming mechanism for the CGOA shelf, leading to higher peak chlorophyll concentrations during the following spring bloom. Enhanced wind stress curl and Ekman pumping are associated with the presence of a low‐pressure system in the northern CGOA, and potentially connected to the large‐scale variability of the Aleutian Low in the North Pacific.
Influence of soot mixing state on aerosol light absorption and single scattering albedo during air mass aging at a polluted regional site in northeastern China
Authors: Cheng Y. F. , Berghof M. , Garland R. M. , Wiedensohler A. , Wehner B. , Müller T. , Su H. , Zhang Y. H. , Achtert P. , Nowak A. , Pöschl U. , Zhu T. , Hu M. , Zeng L. M.
Published: June 2009

An aerosol optical closure study was performed using the observed high time‐ and size‐resolved soot mixing states determined by a Volatility Tandem Differential Mobility Analyzer (VTDMA) at a polluted regional site, Yufa, in the south of Beijing during the summer of 2006. Good agreement was found between the simulated and measured aerosol absorption (σap, R = 0.9) and scattering (σsp, R ≥ 0.95). The soot mixing state at Yufa can be generally determined by VTDMA, in terms of properly predicting the σap using a simple optical model combined with spherical homogeneous and core‐shell coated Mie codes. The possible uncertainties in the modeled σap were discussed. Rapid soot aging was observed, which led to large variations in the fractional contributions to σap by externally mixed and coated soot. On average, about 37% of the σap (∼10–60%) arose by the coated soot. The coating enhancement in σap and σsp of the coated soot can reach up to a factor of 8–10 within several hours owing to the secondary processing during daytime. It was contributed not only by the increased thickness of coating shell, but also the transition of soot from externally mixed to coated one. Hence, assuming constant soot mixing state for the regional climate model is not realistic and may lead to uncertainties. In the highly polluted region in northeastern China, the aerosol single scattering albedo may increase very fast owing to the rapid secondary particle formation and condensation (up to 0.90–0.95). This increase took place although the concurrent coating processing enhanced the light absorption capability of soot.
Seasonal and diurnal variations of organic carbon in PM2.5 in Beijing and the estimation of secondary organic carbon
Authors: Lin Peng , Hu Min , Deng Z. , Slanina J. , Han S. , Kondo Y. , Takegawa N. , Miyazaki Y. , Zhao Y. , Sugimoto N.
Published: June 2009

Organic carbon (OC) and elemental carbon (EC) in PM2.5 were measured hourly with a semicontinuous thermal‐optical analyzer in Beijing, China, during four seasons from November 2005 to October 2006. The average OC concentrations measured at Peking University (PKU) site in urban Beijing were 20 ± 19, 12 ± 7, 10 ± 5, and 18 ± 11 μgC/m3 in winter, spring, summer, and autumn, respectively. Distinct seasonal and diurnal patterns of OC were observed, and their concentrations were significantly influenced by the seasonal and diurnal changes in sources, emission rates, and mesoscale meteorology. The impacts of meteorological parameters such as wind and precipitation on OC and EC concentrations are also discussed. OC and EC concentrations were found to be well correlated in winter, spring, and autumn, indicating their common origins, while their correlation was poorer in summer, especially in the afternoon, indicating that the influence of secondary organic carbon (SOC) was significant for this period. SOC concentrations were estimated by using the EC‐tracer method as about 2.6 ± 3.1, 2.8 ± 2.4, 4.5 ± 2.9, and 4.1 ± 4.0 μgC/m3, accounting for 19%, 27%, 45%, and 23% of total organic carbon in winter, spring, summer, and autumn, respectively. This result showed that the relative contribution of SOC to OC in PM2.5 at this urban location was only comparable to that of primary organic carbon (POC) to OC in summer, while in the other three seasons, OC was dominated by POC.
Reactive uptake coefficients for N2O5 determined from aircraft measurements during the Second Texas Air Quality Study: Comparison to current model parameterizations
Authors: Brown Steven S. , Dubé William P. , Fuchs Hendrik , Ryerson Thomas B. , Wollny Adam G. , Brock Charles A. , Bahreini Roya , Middlebrook Ann M. , Neuman J. Andrew , Atlas Elliot , Roberts James M. , Osthoff Hans D. , Trainer Michael , Fehsenfeld Frederick C. , Ravishankara A. R.
Published: June 2009

This paper presents determinations of reactive uptake coefficients for N2O5, γ(N2O5), on aerosols from nighttime aircraft measurements of ozone, nitrogen oxides, and aerosol surface area on the NOAA P‐3 during Second Texas Air Quality Study (TexAQS II). Determinations based on both the steady state approximation for NO3 and N2O5 and a plume modeling approach yielded γ(N2O5) substantially smaller than current parameterizations used for atmospheric modeling and generally in the range 0.5–6 × 10−3. Dependence of γ(N2O5) on variables such as relative humidity and aerosol composition was not apparent in the determinations, although there was considerable scatter in the data. Determinations were also inconsistent with current parameterizations of the rate coefficient for homogenous hydrolysis of N2O5 by water vapor, which may be as much as a factor of 10 too large. Nocturnal halogen activation via conversion of N2O5 to ClNO2 on chloride aerosol was not determinable from these data, although limits based on laboratory parameterizations and maximum nonrefractory aerosol chloride content showed that this chemistry could have been comparable to direct production of HNO3 in some cases.
Landslide rupture and the probability distribution of mobilized debris volumes
Authors: Stark C. P. , Guzzetti F.
Published: June 2009

Landslide‐driven erosion is controlled by the scale and frequency of slope failures and by the consequent fluxes of debris off the hillslopes. In this paper, we tackle the magnitude‐frequency part of the process and develop a theory of initial slope failure and debris mobilization that reproduces the heavy‐tailed distributions (probability density function or PDFs) observed for landslide source areas and volumes. Landslide rupture propagation is treated as a quasi‐static, noninertial process of simplified elastoplastic deformation with strain weakening; debris runout is not considered. The model tracks the stochastically evolving imbalance of frictional, cohesive, and body forces across a failing slope and uses safety factor concepts to convert the evolving imbalance into a series of incremental rupture growth or arrest probabilities. A single rupture is simulated with a sequence of weighted “coin tosses” with weights set by the growth probabilities. Slope failure treated in this stochastic way is a survival process that generates asymptotically power‐law‐tail PDFs of area and volume for rock and debris slides; predicted scaling exponents are consistent with analyses of landslide inventories. The primary control on the shape of the model PDFs is the relative importance of cohesion over friction in setting slope stability; the scaling of smaller, shallower failures, and the size of the most common landslide volumes, are the result of the low cohesion of soil and regolith, whereas the negative power‐law‐tail scaling for larger failures is tied to the greater cohesion of bedrock.
Supersonic neutral winds and neutral streams in the thermosphere‐ionosphere‐plasmasphere system
Authors: Gardner L. C. , Schunk R. W.
Published: June 2009

Model studies were conducted to determine the conditions that might give rise to supersonic neutral winds in the high‐latitude thermosphere and that can produce neutral streams in the polar wind and plasmasphere. For the supersonic neutral wind study, we used a time‐dependent, three‐dimensional, global thermosphere‐ionosphere model. Simulations were conducted for different seasonal conditions, solar activity levels, cross‐polar‐cap potentials, and convection pattern shapes. Supersonic neutral winds were found to occur at altitudes above 200 km for cross‐polar‐cap potentials greater than about 150 kV, although most of the supersonic winds occurred between 300 and 600 km. The Mach number of the neutral winds was typically less than 1.5, and the supersonic winds were generated within 3 h after enhanced plasma convection. These winds were primarily located in the midnight‐dawn sector of the polar cap, and their dusk‐to‐dawn extent was of the order of 150 km. Also, during enhanced convection, the ion outflow in the polar wind increases because of the elevated plasma temperatures, and this leads to enhanced ion‐neutral charge exchange reactions, and hence, to the production of neutral streams in the polar wind (Neutral Polar Wind). Likewise, on closed magnetic field lines, the upflowing ionospheric ions can charge exchange with the background neutrals, and this produces neutral streams in the plasmasphere (Neutral Plasmasphere Wind). Coupled models of the ionosphere‐polar wind‐exosphere and ionosphere‐plasmasphere‐exosphere were used to elucidate the basic characteristics of these neutral streams. An important result is that the neutral O streams typically do not have sufficient energy to escape in both the polar wind and plasmasphere, and they rain down on the global thermosphere (Neutral Rain). The downward streaming neutral O atoms pass through the exobase at 500–600 km and provide a source of momentum and energy for the thermosphere. The results presented here correspond to a focused modeling study that was presented at the Ionospheric Effects Symposium (May 2008).
Strain partitioning in the axial NW Alps since the Oligocene
Authors: Malusà Marco G. , Polino Riccardo , Zattin Massimiliano
Published: June 2009

This work analyzes the postmetamorphic evolution of the northwestern Alps thanks to a multiscale field geology study integrated by fission track analysis. It illustrates how the fission track method, constraining throws along major faults and age of mesoscale deformation, provides interpretation keys to detangle complex structural data sets. Results are discussed within the framework of the Alps‐Apennines knot and give new insights on strain partitioning within transpressional orogenic belts. The axial NW Alps acted since the late Oligocene as an orogen‐scale shear zone accommodating, in the Aosta Valley, dextral strike slip coeval with forward propagation of external thrusts. Within this transcurrent belt, right‐lateral deformation was partitioned between the fast exhuming Western Block and the already unroofed Eastern Block. These blocks show contrasting structural characters. The former is cut by first‐order longitudinal structures bounding major tectonostratigraphic units. The latter is fragmented by complex patterns of lower‐order faults interpreted as subsidiary shears. The onset of mesoscale extension, widespread in the Eastern Block, is diachronous across the belt and migrated through time toward the European foreland. Transition from syncollisional shortening to orogen‐scale transcurrence observed in the NW Alps corresponds to a regional strain field variation, documented in the mid‐Oligocene all around the Alps‐Apennines knot, which is possibly related to a change of the Adria trajectory relative to Europe. Since the late Oligocene, deformation associated with oblique plate convergence was partitioned between strike slip in the axial belt and thrusting in external areas. Most of the shortening was accommodated in the Helvetic chains (102km). Deformation was limited elsewhere to an order of 101km.
Source regions of banded chorus
Authors: Bell T. F. , Inan U. S. , Haque N. , Pickett J. S.
Published: June 2009

ELF/VLF chorus emissions are very intense electromagnetic plasma waves that are naturally and spontaneously excited near the magnetic equatorial plane outside the plasmasphere during periods of magnetic disturbance. These emissions are believed to play an important role in the acceleration of 10 to 100 keV radiation belt electrons to MeV energies during the disturbed time periods. Spacecraft observations near the magnetic equatorial plane in the regions where chorus emissions are generated show that the chorus often appears in two distinct frequency bands, one band below fce/2 and one band above fce/2, where fce is the local electron gyrofrequency. This configuration is known as banded chorus. In the present paper we show that this type of configuration can be readily explained if it is assumed that the chorus is excited in ducts of either enhanced or depleted cold plasma density.
Lithospheric velocity structure of the New Madrid Seismic Zone: A joint teleseismic and local P tomographic study
Authors: Zhang Qie , Sandvol Eric , Liu Mian
Published: June 2009

The enigmatic seismicity in the New Madrid Seismic Zone (NMSZ) has been attributed to some abnormal lithospheric structure, including the presence of dense mafic intrusions and a low‐viscosity lower crust. However, the area's detailed lithospheric structure remains unclear. Here we invert 2,056 teleseismic P and 12,226 local P first arrival times from a recent nine‐year dataset to infer the lithospheric velocity structure beneath the NMSZ. Our results show that the seismically active zone is associated with a local, NE–SW trending low‐velocity anomaly in the lower crust and upper mantle, instead of high‐velocity intrusive bodies proposed in previous studies. The low‐velocity anomaly is on the edge of a high‐velocity lithospheric block, consistent with the notion of stress concentration near rheological boundaries. This lithospheric weak zone may shift stress to the upper crust when loaded, thus leading to repeated shallow earthquakes.
Evaluation of precipitation in the Intermountain Region as simulated by the NARCCAP regional climate models
Authors: Wang Shih‐Yu , Gillies Robert R. , Takle Eugene S. , Gutowski William J.
Published: June 2009

We evaluated the precipitation climatology of the Intermountain Region (IR) as generated by the six regional climate models of the North American Regional Climate Change Assessment Program (NARCCAP). A complex combination of the precipitation annual and semiannual cycles with their different phases form four major climate regimes over the IR. Each model produces systematic biases in the central IR where these different climate regimes meet. The simulated annual cycles are universally too strong, and the winter precipitation is too large. On the other hand, the semiannual cycles are relatively well produced. The strong annual cycles and the excess winter precipitation obscure the signals of spring/summer precipitation and may have led to false signals of the El Niño‐Southern Oscillation (ENSO) found in the central IR. Therefore, caution is advised when interpreting the simulated NARCCAP precipitation for the IR.
Intercontinental source attribution of ozone pollution at western U.S. sites using an adjoint method
Authors: Zhang Lin , Jacob Daniel J. , Kopacz Monika , Henze Daven K. , Singh Kumaresh , Jaffe Daniel A.
Published: June 2009

We use the GEOS‐Chem chemical transport model and its adjoint to quantify source contributions to ozone pollution at two adjacent sites on the U.S. west coast in spring 2006: Mt. Bachelor Observatory (MBO) at 2.7 km altitude and Trinidad Head (TH) at sea level. The adjoint computes the sensitivity of ozone concentrations at the receptor sites to ozone production rates at 2° × 2.5° resolution over the history of air parcels reaching the site. MBO experiences distinct Asian ozone pollution episodes; most of the ozone production in these episodes takes place over East Asia with maxima over northeast China and southern Japan, adding to a diffuse background production distributed over the extratropical northern hemisphere. TH shows the same Asian origins for ozone as MBO but no distinct Asian pollution episodes. We find that transpacific pollution plumes transported in the free troposphere are diluted by a factor of 3 when entrained into the boundary layer, explaining why these plumes are undetectable in U.S. surface air.
Vegetation dynamics and plant CO2 responses as positive feedbacks in a greenhouse world
Authors: O'ishi Ryouta , Abe‐Ouchi Ayako , Prentice I. Colin , Sitch Stephen
Published: June 2009

An atmosphere‐ocean‐vegetation coupled model is used to quantify the biogeophysical feedback that emerges as vegetation adjusts dynamically to a quadrupling of atmospheric CO2. This feedback amplifies global warming by 13%. About half of it is due to climatically induced expansion of boreal forest into tundra, reinforced by reductions in snow and sea ice cover. The other half represents a global climatic effect of increased vegetative cover (an indirect consequence of plant physiological responses to CO2) in the semi‐arid subtropics. Enhanced absorption of shortwave radiation in these regions produces a net surface warming, which the atmosphere communicates poleward. The greatest vegetation‐induced warming is co‐located with large, vulnerable carbon stores in the north. These lose carbon, so that in the long term, the biospheric response to CO2 and climate change becomes dominated by positive feedbacks that overwhelm the effect of CO2 fertilization on terrestrial carbon stocks.
Equatorial zonal electric fields inferred from a 3‐D electrostatic potential model and ground‐based magnetic field measurements
Authors: Shume E. B. , de Paula E. R. , Maus S. , Hysell D. L. , Rodrigues F. S. , Bekele A.
Published: June 2009

We present a new technique to infer quiet time zonal electric fields in the daytime equatorial ionosphere. The electric field inference technique utilizes a three‐dimensional (3‐D) electrostatic potential model of the low‐latitude ionosphere constrained by ground‐based magnetic field measurements. To test this technique, inferred zonal electric fields for the Peruvian sector in Jicamarca (11.95°S, 283.13°E, 0.6°N dip latitude) were compared with zonal electric field (vertical drift) measurements made by the Jicamarca Incoherent Scatter Radar. The comparison shows a good agreement between the inferred and measured electric fields. An example of electric field estimation for Davao (7.4°N, 125.4°E, 0.58°S dip latitude) in the Philippines sector is also presented in this report. Inferred electric fields for Davao are in good agreement with F region vertical plasma drifts measured by drift sensors onboard the AE‐E and ROCSAT‐1 satellites on that longitude sector. Our results suggest that realistic estimates of quiet time zonal electric fields for the equatorial ionosphere can be obtained from the 3‐D potential model whenever observatory magnetic field measurements are available.
Inhibition of Src Activity Decreases Tyrosine Phosphorylation of Occludin in Brain Capillaries and Attenuates Increase in Permeability of the Blood-Brain Barrier after Transient Focal Cerebral Ischemia
Authors: Takenaga Yuji , Takagi Norio , Murotomi Kazutoshi , Tanonaka Kouichi , Takeo Satoshi
Published: June 2009

Disruption of the blood-brain barrier (BBB) caused by cerebral ischemia can initiate the development and progression of brain injuries, which may lead to irreversible dysfunction of the central nervous system. It is likely that tyrosine phosphorylation of a membrane-associated tight junctional protein, occludin, is important for the interaction of occludin with intracellular proteins, ZO-1 to ZO-3, and it regulates vascular permeability. Little is known about the pathophysiological alterations of tight junctional proteins after transient focal cerebral ischemia. In this study, we examined the tyrosine phosphorylation of occludin in isolated brain capillaries after transient focal cerebral ischemia. We further examined the effects of the Src-family tyrosine kinase inhibitor, PP2, on the tyrosine phosphorylation of occludin and on vascular permeability and infarct volume. Transient focal ischemia increased the tyrosine phosphorylation of occludin in the isolated brain capillaries. The administration of PP2 attenuated this phosphorylation, which was coincident with an inhibition of BBB leakage and a decrease in infarct volume. These results suggest that the increase in the tyrosine phosphorylation of occludin in the brain capillaries may be linked to the disruption of tight junctions, whose disruption can cause dysfunction of the BBB and the consequent increase in infarct volume.
Reversal of Small, Dense LDL Subclass Phenotype by Normalization of Adiposity
Authors: Siri‐Tarino Patty W. , Williams Paul T. , Fernstrom Harriet S. , Rawlings Robin S. , Krauss Ronald M.
Published: June 2009

Excess adiposity and high‐carbohydrate diets have been associated with an atherogenic lipoprotein phenotype (ALP) characterized by increased concentrations of small, dense low‐density lipoprotein (LDL) particles (pattern B). We tested whether weight loss and normalization of adiposity could reverse ALP in overweight men with pattern B. After consuming a moderate‐carbohydrate, high‐fat diet for 3 weeks, pattern B and nonpattern B (pattern A) men were randomized to a weight loss (n = 60 and n = 36, respectively) or control weight‐stable arm (n = 20 and n = 17, respectively). Men in the weight loss arm consumed ∼1,000 fewer calories per day over 9 weeks to induce an average ∼9 kg weight loss. In the control group, weight stability was maintained for 4 weeks after randomization. Weight loss led to the conversion of pattern B to pattern A in 58% of baseline pattern B men. Among men who achieved BMIs of <25 kg/m2 (62% of pattern B men vs. 83% of pattern A men), 81% of pattern B men converted to pattern A. Weight loss was associated with a significantly greater decrease in small, dense LDL subclass 3b in pattern B relative to pattern A men. The lipoprotein profiles of pattern A men who converted from pattern B were comparable to those of men with pattern A at baseline. Conversion of LDL subclass pattern B to pattern A and reversal of ALP can be achieved in a high proportion of overweight men by normalization of adiposity.
Reflections on Reflections: Learning Processes in Speech and Language Pathology Students' Clinical Education
Authors: Meilijson Sara , Katzenberger Irit
Published: June 2009

The investigators' goal was to study the early clinical education processes of students enrolled in a speech-language pathology program by analyzing content of their written reflections. In this study, the authors propose and apply a method of analyzing written reflections of the students during the first stages of their clinical education. Forty written reflections taken from the observation reports submitted by the students were compiled from the first and second year students of the Communication Disorders Department. A quantitative (number of words and clauses of the entire report and its content categories) and a qualitative analysis (based upon the three qualitative levels of reflections suggested by Boud, Keogh, & Walker, 1985) were performed. Results show that text length of reflections increased with learning. Students use different content categories at different stages of the learning period. The level of reflection used most frequently by the students is “returning to experience.” The content categories raised by the students reflected complexity of the task, acquired knowledge of the students, and their ongoing experience. Written reflections may be used to evaluate the performance of students in the clinical education process.
Seeing is Believing: Linking Data with Knowledge
Authors: Dadzie Aba-Sah , Lanfranchi Vitaveska , Petrelli Daniela
Published: June 2009

The analysis of data using a visual tool is rarely a task done in isolation, it tends to be part of a wider goal: that of making sense of the current situation, often to support decision-making. A user-centred approach is needed in order to properly design interaction that supports sense-making incorporating visual data analysis. This paper reports the experience gained in X-Media, a project that aims to support knowledge management (KM), sharing and reuse across different media in large enterprises. We report the user-centred design approach adopted and the design phases that led to the first prototype. A user evaluation was conducted to assess the design and how different levels of data, information and knowledge were mapped using alternative visual tools. The results show that a clear separation of the visual data analysis from other sense-making sub-tasks helps users in focussing their attention. Users particularly appreciated the data analysis across different media and formats, as well as the support for contextualising information within the broader perspective of KM. Further work is needed to develop more fully intuitive visualisations that exploit the richer information in multimedia documents and make the multiple connections between data more easily accessible.
Experimental study of impurity screening in the edge ergodic layer of the Large Helical Device using carbon emissions of CIII to CVI
Authors: Chowdhuri Malay Bikas , Morita Shigeru , Kobayashi Masahiro , Goto Motoshi , Zhou Hangyu , Masuzaki Suguru , Morisaki Tomohiro , Narihara Kazumichi , Yamada Ichihiro , Feng Yuehe
Published: June 2009

Four resonance transitions of CIII (977.03 Å:2s2 S10-2s2p P11), CIV (1550 Å:2s S2-2p P2), CV (40.27 Å:1s2 S10-1s2p P11), and CVI (33.73 Å:1s S2-2p P2) have been observed in vacuum ultraviolet and extreme ultraviolet regions to study the edge carbon impurity transport in the Large Helical Device ergodic layer. Here, CIII and CIV indicate the carbon influx at the outside boundary of the ergodic layer and CV and CVI indicate the ions in higher ionization stages, which have already experienced the transport in the ergodic layer. The intensity ratio of CV+CVI to CIII+CIV, therefore, represents the degree of impurity screening, which has been analyzed with different edge plasma parameters and ergodic magnetic field structures. The ratio decreases by two orders of magnitude with an increase in electron density ne in the range of 1–8×1019 m−3. The CV and CVI emissions tend to decrease with ne, whereas the CIII and CIV emissions monotonically increase with ne. The result suggests an enhancement of the impurity screening in the higher ne range due to the increasing ion-impurity collision frequency (νΖi≡1/τs=3.4×104 s−1 at ne=2×1019 m−3 and 1.0×105 s−1 at 6×1019 m−3 for CV). The friction force parallel to the magnetic fields plays an important role in the edge impurity transport within the ergodic layer. When the ergodic layer structure is thicker, the ratio systematically decreases mainly due to a reduction in CV+CVI emissions. The ratio is also studied by changing the radial position of an externally supplied m/n=1/1 island. When the island is positioned in the ergodic layer, the ratio indicates a remarkable change, i.e., reduction in CV+CVI and increase in CIII+CIV. These experiments demonstrate that the modification of the ergodic magnetic field structure makes a clear change to the edge impurity transport. When the background ion species is changed from hydrogen to helium, the ratio is clearly reduced, at least at ne≤4×1019 m−3, suggesting the enhancement of the impurity screening effect due to the increased collisionality. Finally, the experimental result is simulated using three-dimensional edge transport code of EMC3-EIRENE. The density dependence of the carbon ratio can be well reproduced with a simulation code suggesting that impurity screening is induced in the ergodic magnetic field layer.
Magnetic switching field distribution of patterned CoPt dots
Authors: Abes M. , Rastei M. V. , Venuat J. , Carvalho A. , Boukari S. , Beaurepaire E. , Panissod P. , Dinia A. , Bucher J. P. , Pierron-Bohnes V.
Published: June 2009

We report on the interplay between the structural and the magnetic properties of different size dots patterned in two structurally different CoPt thin films with L10 order. The significant changes observed in the magnetic domain configuration and coercive field between the samples are interpreted in the light of crystalline structure. The magnetic hysteresis curves measured for single/several dots are compared to those of the dot assembly and discussed in view of structure and edge defects. In particular, the concentration fluctuations are found to enlarge the magnetic switching field distribution despite the presence of a single variant of the L10 phase. In turn, the distribution is narrow in samples that are homogeneous in concentration and contain well defined magnetization nucleation sites, namely, the x and y variants of the L10 phase formed during annealing.
Effects of piezoelectric potential on the transport characteristics of metal-ZnO nanowire-metal field effect transistor
Authors: Gao Zhiyuan , Zhou Jun , Gu Yudong , Fei Peng , Hao Yue , Bao Gang , Wang Zhong Lin
Published: June 2009

We have investigated the effects of piezoelectric potential in a ZnO nanowire on the transport characteristics of the nanowire based field effect transistor through numerical calculations and experimental observations. Under different straining conditions including stretching, compressing, twisting, and their combination, a piezoelectric potential is created throughout the nanowire to modulate/alternate the transport property of the metal-ZnO nanowire contacts, resulting in a switch between symmetric and asymmetric contacts at the two ends, or even turning an Ohmic contact type into a diode. The commonly observed natural rectifying behavior of the as-fabricated ZnO nanowire can be attributed to the strain that was unpurposely created in the nanowire during device fabrication and material handling. This work provides further evidence on piezopotential governed electronic transport and devices, e.g., piezotronics.
Modeling and direct extraction of band offset induced by stress engineering in silicon-on-insulator metal-oxide-semiconductor field effect transistors: Implications for device reliability
Authors: Garros X. , Rochette F. , Andrieu F. , Baudot S. , Reimbold G. , Aulnette C. , Daval N. , Boulanger F.
Published: June 2009

We study the performance and reliability of metal-oxide-semiconductor field effect transistors fabricated on strained and unstrained silicon on insulator substrates, sSOI and SOI, respectively. The biaxial strain strongly enhances electron mobility and changes the threshold voltage, Vt, of the devices. We show that the Vt shift in the “ideal SOI structures,” i.e., with no oxide defects, is due to the conduction band offset induced by strain ΔEc and therefore can be used for the stress monitoring. The biaxial strain also affects the gate oxide leakage current. A new method to extract ΔEc from the leakage current measurements is proposed. This method is less sensitive to the gate oxide defects than the one based on Vt shift. A complete modeling of leakage current in SOI and sSOI transistors is presented. Due to the strong confinement at the Si/SiO2 interface the leakage current in the Fowler–Nordheim (FN) regime mainly results from electron tunneling in the subband associated to the ground level E0Δ2. A simple FN model is therefore used to extract the ΔEc from the variation in the effective barrier height ϕbFN between the Si film and the SiO2 oxide. Based on this experimental and accurate extraction of ΔEc, realistic values of the deformation potentials in Si are finally proposed. The final part of the paper discusses the different implications of this band offset ΔEc on device performance and reliability. It is demonstrated that strained devices exhibit reduced leakage currents and a superior reliability, in terms of interface state density and oxide breakdown, than unstrained devices.
Two different coercivity lattices in Co/Pd multilayers generated by single-pulse direct laser interference lithography
Authors: Leufke Philipp M. , Riedel Stephen , Lee Min-Sang , Li Jie , Rohrmann Hartmut , Eimüller Thomas , Leiderer Paul , Boneberg Johannes , Schatz Günter , Albrecht Manfred
Published: June 2009

We report on magnetic structuring of Co/Pd multilayer films with strong perpendicular magnetic anisotropy by single-pulse direct laser interference lithography technique. Multibeam laser interference generates patterns of various types. The intense laser irradiation at interference maxima causes chemical intermixing at Co/Pd interfaces, leading to local changes in magnetic properties such as the creation of pinning centers and the reduction in the strength of magnetic anisotropy. We use magnetic force microscopy and Kerr microscopy to study the magnetization reversal processes in the patterned samples and find that the structures show three distinctly different behaviors depending on the intensity of the laser used for irradiation.
Combined small-angle x-ray scattering/extended x-ray absorption fine structure study of coated Co nanoclusters in bis(2-ethylhexyl)sulfosuccinate
Authors: Longo A. , Giordano F. , Giannici F. , Martorana A. , Portale G. , Ruggirello A. , Turco Liveri V.
Published: June 2009

Chemically stable cobalt nanostructures have been prepared with Co(II) reduction in the confined space of cobalt bis(2-ethylhexyl)sulfosuccinate, Co(AOT)2, reverse micelles dispersed in n-heptane. The reaction was carried out by adding a solution of sodium borohydride in ethanol (1% weight) to a 0.2M micellar solution of Co(AOT)2 in n-heptane at a reductant to Co(II) molar ratio of 4. This procedure involves the rapid formation of surfactant-coated Co nanoparticles followed by their slow separation as nanostructures embedded in a sodium bis(2-ethylhexyl)sulfosuccinate matrix. The resulting composites, characterized by extended x-ray absorption fine structure and small-angle x-ray scattering, showed the presence of subnanometer sized cobalt nanoparticles aggregated together to form elongated structures coated by the surfactant molecules.
Eigenmode dispersion relations in radially inhomogeneous helicon plasmas
Authors: Cho Suwon
Published: June 2009

The eigenmode dispersion relation is studied for a helicon plasma whose density varies in the radial direction. It is found that eigenmodes are strongly excited in a weakly collisional plasma when the dispersion relation obtained neglecting electron inertia is approximately satisfied and their orders vary as the magnetic field does for m=+1 (m is the azimuthal mode number) whether the density is uniform or not. But the inhomogeneity yields different results for m=−1. For sufficiently steep density profiles, the radial eigenmode of the lowest order is most strongly excited regardless of the magnetic field and a much higher density is required for m=−1 than m=+1 at a given magnetic field.
Magnetite nanoparticles with no surface spin canting
Authors: Roca A. G. , Niznansky D. , Poltierova-Vejpravova J. , Bittova B. , González-Fernández M. A. , Serna C. J. , Morales M. P.
Published: June 2009

Surface spin canting has been studied for high quality magnetite nanoparticles in terms of size and shape uniformity. Particles were prepared by thermal decomposition of organic precursors in organic media and in the presence of oleic acid. Results are compared to spin canting effect for magnetic iron oxide nanoparticles of similar size prepared by coprecipitation and subsequently coated with silica. Magnetic characterization and Mössbauer spectroscopy at low temperature and in the presence of a magnetic field have been used in this study. Transmission electron microscopy images and x-ray diffractograms show that iron oxide nanoparticles synthesized by thermal decomposition are more uniform than those prepared by coprecipitation, and they have higher crystal order. Magnetic measurements show superparamagnetic behavior for both samples at room temperature but particles synthesized by thermal decomposition shows higher saturation magnetization and lower coercivity at low temperature. The imaginary part of the ac susceptibility has been used to support the presence of mainly magnetite instead of maghemite in these iron oxide nanoparticles. Mössbauer measurements with and without field demonstrate surface spin canting, only in the octahedral positions for the coprecipitation particles. However, high synthesis temperature and the presence of oleic acid molecules covalently bonded at the particle surface, accounting for the lack of spin canting in particles prepared by thermal decomposition, which justifies the high saturation magnetization and low coercivity at low temperature.