bluuebunny/crossref_metadata_2025 huggingface dataset:
Paranoid Explanations of Experience: A Novel Experimental Study
Authors: Green Catherine E. L. , Freeman Daniel , Kuipers Elizabeth , Bebbington Paul , Fowler David , Dunn Graham , Garety Philippa A.
Published: September 2010

Background:Paranoia is a common experience in the non-clinical population. We use a novel experimental methodology to investigate paranoid ideas in individuals without a history of mental illness.Aims:We aimed to determine whether this paradigm could elicit unfounded paranoid thoughts and whether these thoughts could be predicted by factors from a cognitive model.Method:Fifty-eight individuals took part and completed measures assessing trait paranoia, mood, self and other schema and attributional style. They were exposed to two experimental events: 1) an interruption to the testing session by a stooge, and 2) a recording of laughter played outside the testing room and subsequently asked about their explanations for these events.Results:15.5% (n= 9) of the sample gave a paranoid explanation for at least one of the experimental events. The remainder reported generally neutral explanations. Individuals with a paranoid explanation reported significantly higher levels of trait paranoia. Factors predictive of a paranoid interpretation were interpersonal sensitivity and attributional style.Conclusions:The results show that spontaneous paranoid explanations can be elicited in non-clinical individuals, even for quite neutral events. In line with current theories, the findings suggest that emotional processes contribute to paranoid interpretations of events, although, as a novel study with a modest sample, it requires replication.
How Does Thought-Action Fusion Relate to Responsibility Attitudes and Thought Suppression to Aggravate the Obsessive-Compulsive Symptoms?
Authors: Altın Müjgan , Gençöz Tülin
Published: September 2010

Background: Comprehensive cognitive theories of obsessive compulsive disorder (OCD) propose that clinical obsessions and compulsions arise from specific sorts of dysfunctional beliefs and appraisals, such as inflated sense of responsibility, thought-action fusion (TAF), and thought suppression. Aims: The present study aimed to examine the mediator roles of responsibility and thought suppression between TAF and obsessive-compulsive symptoms. Specifically, it aimed to explore the relative effects of TAF factors (i.e. morality and likelihood) on inflated sense of responsibility and on thought suppression to increase the obsessive qualities of intrusions. Method: Two hundred and eighty-three Turkish undergraduate students completed a battery of measures on responsibility, thought suppression, TAF, OC symptoms, and depression. Results: A series of hierarchical regression analyses, where depressive symptoms were controlled for, indicated that TAF-morality and TAF-likelihood follow different paths toward OC symptoms. Although TAF-morality associated with inflated sense of responsibility, TAF-likelihood associated with thought suppression efforts, and in turn these factors increased OC symptoms. Conclusions: These findings provide support for the critical role of sense of responsibility and thought suppression between the relationship of TAF and OC symptoms. Findings were discussed in line with the literature.
Searching for the Anatomy of Dissociative Amnesia
Authors: Staniloiu Angelica , Markowitsch Hans J.
Published: September 2010

Brain damage was traditionally seen as the product of a neurological disease or injury. Nevertheless, modern brain imaging techniques have provided increasing evidence for alterations in brain tissue and metabolism for a number of psychiatric disorders. Though for a while “dissociated” ( Spiegel, 2006 ) from the clinical and scientific arena, dissociative disorders have in the last several years received a renewed interest among several groups of researchers, who embarked on the work of disentangling their neural correlates. We review data from our own research as well as others, which point to distinct changes in brain regions underlying dissociative amnes(t)ic disorders. These changes may consist of overall reductions in brain metabolism or more selective alterations primarily in the right temporo-frontal cortices. Recent evidence with refined magnetic resonance imaging techniques furthermore reveals selective fiber degenerations in these regions. While these changes may persist and probably even intensify in some patients, they may be reversible in others – especially if treatment is carried out successfully within short time after onset. Implications of these findings for the pathogenetic conceptualization of dissociative amnes(t)ic disorders are outlined.
Assessing Multidimensional Exercise Amotivation Among Adults and Older Individuals
Authors: Vlachopoulos Symeon P. , Letsiou Markela , Palaiologou Anastasia , Leptokaridou Elisavet T. , Gigoudi Maria A.
Published: September 2010

The present study reported on the inclusion of a task-characteristics assessment to the Amotivation Toward Exercise Scale (ATES; Vlachopoulos & Gigoudi, 2008 ) and the evaluation of the revised self-report instrument (ATES-2) among physically active Greek-speaking adults and older individuals. The ATES-2 was completed by two samples of 201 and 150 physically active older individuals aged from 50 to 81 years and 781 adult exercise participants aged from 18 to 68 years. For both populations the results revealed a sound factor structure, strong internal consistency, and evidence supporting five correlated factors against five uncorrelated factors, a single factor, and a hierarchical structure. Factor discriminant validity analyses revealed five distinct factors for the older individuals whereas the outcome and value amotivation factors were perceived as indistinguishable for the adult exercise participants. Further, regression analyses provided initial support for the predictive validity of the scale scores. Overall, initial psychometric evidence emerged in support of the ATES-2 scores pointing to a promising instrument for the study of amotivation beliefs in regard to exercise behavior for both physically active adults and older individuals.
Factorial and Construct Validity of the Sibling Relationship Questionnaire
Authors: Derkman Marleen M. S. , Scholte Ron H. J. , Van der Veld William M. , Engels Rutger C. M. E.
Published: September 2010

The psychometric properties of the shortened version of the Sibling Relationship Questionnaire (SRQ; Furman & Buhrmester, 1985 ) were examined in a sample of 428 Dutch adolescents, aged 13 to 16. In order to examine the dimensions Warmth/Closeness and Conflict, as proposed by Furman and Buhrmester, we first conducted confirmatory factor analyses. Second, we investigated the construct validity by correlating Warmth/Closeness and Conflict with internalizing and externalizing behaviors and the quality of relationship with parents. Third, we determined the internal reliability of Warmth/Closeness and Conflict and the underlying qualities by computing Cronbach’s αs. The results confirmed the dimensions Warmth/Closeness and Conflict as major aspects of sibling relationships. Moreover, the construct validity of the instrument and internal consistency for these dimensions and the underlying qualities proved to be good. Our findings underscore the psychometric properties of the SRQ, in that it appears to be a valid and reliable measure to assess Warmth/Closeness and Conflict in sibling relationships.
Development of the Remoralization Scale
Authors: Vissers Wiede , Keijsers Ger. P. J. , van der Veld William M. , de Jong Cor A. J. , Hutschemaekers Giel J. M.
Published: September 2010

Remoralization is the process of restoration of morale. Remoralization constitutes an important step in the therapeutic change process. Because no appropriate self-report instrument was available to indicate the level of morale in mental health care, the Remoralization Scale (RS) was developed. In a first study (299 outpatients), a pool of 69 items was examined to produce an initial scale with 16 items with a unidimensional factor structure. In a second study (199 outpatients, 192 nonpatients), the unidimensionality and scalar invariance of the initial scale was tested. To make the RS as short and easy to complete as possible, four items with low factor loadings were removed. In a third study (124 students), the test-retest reliability (r = 0.89) and internal consistency (α = 0.91) of the RS were estimated. In a fourth study, the construct validity of the RS was investigated using a demoralization scale (r = –.72) and scales that measure anxiety (r = –.52), depression (r = –.50), somatic symptoms (r = –.36), and social dysfunction (r = –.37). In a fifth study (23 panic outpatients), the sensitivity of the RS to therapeutic change was examined and found to be good. In closing, limitations of the RS are discussed.
Seven-Factor Model of Emotional Intelligence as Measured by Genos EI
Authors: Gignac Gilles
Published: September 2010

In this investigation, a series of progressively more complex factor models was tested based on self-report and rater-report data derived from the workplace version of the Genos Emotional Intelligence Inventory (Genos EI). Based on a total sample of 4775 individual self-reports and 6848 rater-reports, a theoretically derived higher-order 7-factor model of emotional intelligence (EI) was found to be adequately well-fitting, in comparison to a competing global EI single-factor model and a five-factor model of EI. Internal consistency reliabilities associated with the total scale scores were approximately .95 and the subscale score reliabilities were approximately .80. The results are interpreted as largely supportive of a 7-factor model of EI as measured by Genos EI in both self- and rater-report formats.
Attributing the variability of eddy‐covariance CO2 flux measurements across temporal scales using geostatistical regression for a mixed northern hardwood forest
Authors: Mueller Kim L. , Yadav Vineet , Curtis Peter S. , Vogel Chris , Michalak Anna M.
Published: September 2010

The relationships between terrestrial carbon dioxide flux and its primary environmental drivers are uncertain because the processes controlling CO2 cycling, especially at ecosystem scales, are not well understood. This uncertainty is compounded by the fact that the importance of controlling processes, and therefore environmental drivers, may differ across temporal scales. This paper presents and applies a geostatistical regression (GR) approach that can be used with eddy‐covariance data to investigate the relationships between carbon flux and environmental variables at multiple time scales, ranging from monthly to daily. The approach uses an adaptation of the Bayes Information Criterion to identify an optimal set of environmental variables that are able to explain the observed variability in carbon flux. In addition, GR quantifies the temporal correlation in the portion of the flux signal that cannot be explained by the selected variables and directly accounts for this correlation in the analysis. This GR approach was applied to data from the University of Michigan Biological Station (UMBS) AmeriFlux site to (i) identify the dominant explanatory variables for Net Ecosystem Exchange (NEE), Gross Ecosystem Exchange (GEE), and heterotrophic and autotrophic respiration (Rh+a) at different temporal scales, (ii) evaluate whether environmental variables can be used to isolate the GEE and Rh+a signals from the NEE measurements, and (iii) determine the impact of temporal scale on the inferred relationships between environmental variables and CO2 flux. The results confirm the strong correlation between respiration and temperature and the influence of solar radiation on carbon uptake during the growing season. In addition, results highlight the influence of variables such as precipitation, vapor pressure deficit, and the fraction of photosynthetically active radiation (fPAR) in carbon cycling at UMBS. Many relationships between flux and auxiliary variables are found to be scale‐dependent. Site‐specific and remote‐sensing leaf area index and fPAR data are not found to be interchangeable at finer temporal scales. Results also show that a linear GR model is able to capture what may initially appear to be nonlinear relationships between flux and environmental variables, because this apparent nonlinearity is found to be explained by the covariability among key auxiliary variables. Finally, results indicate that GR can be used to identify variables that partially isolate GEE and Rh+a from the NEE signal at finer temporal scales at UMBS.
On the role of the mesoscale circulation on an idealized coastal upwelling ecosystem
Authors: Lathuilière C. , Echevin V. , Lévy M. , Madec G.
Published: September 2010

An idealized circulation model of coastal upwelling coupled to an ecosystem model has been built to address the impact of features such as eddies and filaments emerging from mesoscale dynamics on a marine ecosystem. The model mimics coastal upwelling along an infinite straight coast with north–south cyclic boundary conditions. Thanks to the parametrization of the geostrophic onshore flow in the thermocline, the circulation captures the typical characteristics of a coastal upwelling region: an equatorward coastal jet, a poleward undercurrent along the continental slope and mesoscale eddies and filaments. This eddying three‐dimensional simulation is compared to a two‐dimensional simulation using the averaged velocity field of the first simulation as velocity field. This approach allows us to compare simulations having similar upwelling and nutrient input but differing in the nature of the flow. An offshore spreading of the phytoplankton bloom is found in the eddying simulation. The width of the productive coastal band is increased from 80 km to 200 km by the mesoscale activity. A biogeochemical budget carried out in a 300 km‐wide coastal band provides evidence that mesoscale activity decreases the total phytoplankton content mainly by exporting a significant part of the surface phytoplankton below the euphotic layer. In presence of mesoscale activity, the downward and offshore export of phytoplankton, zooplankton and detritus significantly contributes to total export of organic matter out of the surface coastal ocean, whereas their contribution to export is weak in the two‐dimensional case.
Coastal observations of weather features in Senegal during the African Monsoon Multidisciplinary Analysis Special Observing Period 3
Authors: Jenkins G. , Kucera P. , Joseph E. , Fuentes J. , Gaye A. , Gerlach J. , Roux F. , Viltard N. , Papazzoni M. , Protat A. , Bouniol D. , Reynolds A. , Arnault J. , Badiane D. , Kebe F. , Camara M. , Sall S. , Ndiaye S. A. , Deme A.
Published: September 2010

During 15 August through 30 September 2006 (Special Observing Period 3, SOP3), key weather measurements are obtained from ground and aircraft platforms during the African Monsoon Multidisciplinary Analysis campaign. Key measurements are aimed at investigating African easterly waves (AEWs) and mesoscale convective systems in a coastal environment as they transition to the eastern Atlantic Ocean. Ground and aircraft instruments include polarimetric radar, a coarse and a high‐density rain gauge network, surface chemical measurements, 12 m meteorological measurement, broadband IR, solar and microwave measurements, rawinsonde, aircraft dropsonde, lidar, and cloud radar measurements. Ground observations during SOP3 show that Senegal was influenced by 5 squall lines, 6 Saharan air layer intrusions, and 10 AEWs. Downstream tropical cyclones developed were associated with the passage of four AEWs. FA‐20 aircraft measurements of microphysical aspects of 22 September squall line and several nondeveloping AEWs over the extreme eastern Atlantic Ocean are presented.
Willingness‐to‐pay for steelhead trout fishing: Implications of two‐step consumer decisions with short‐run endowments
Authors: McKean John R. , Johnson Donn , Taylor R. Garth
Published: September 2010

Choice of the appropriate model of economic behavior is important for the measurement of nonmarket demand and benefits. Several travel cost demand model specifications are currently in use. Uncertainty exists over the efficacy of these approaches, and more theoretical and empirical study is warranted. Thus travel cost models with differing assumptions about labor markets and consumer behavior were applied to estimate the demand for steelhead trout sportfishing on an unimpounded reach of the Snake River near Lewiston, Idaho. We introduce a modified two‐step decision model that incorporates endogenous time value using a latent index variable approach. The focus is on the importance of distinguishing between short‐run and long‐run consumer decision variables in a consistent manner. A modified Barnett two‐step decision model was found superior to other models tested.
Tidal modulation of slow slip in Cascadia
Authors: Hawthorne Jessica C. , Rubin Allan M.
Published: September 2010

Several studies have shown that the seismic tremor in episodic tremor and slip is tidally modulated, suggesting a sensitivity to the rather small tidal stresses. We address whether the slip rate in slow slip events is also tidally modulated by examining data from six borehole strainmeters in northwest Washington and southern Vancouver Island. We simultaneously fit data from multiple stations and from slow slip events occurring over a 3 year interval from January 2007 to June 2009, as we are unable to extract a meaningful signal from a single record. We find modulation of the strain rate with a 12.4 h period, that of the tide with the largest amplitude, that is significant at the 99% level. The amplitude of this modulation suggests that the slip rate during slow slip events oscillates, on average, 25% above and below its mean value during a tidal cycle. Tidal modulation estimates at three other periods are significant with more than 70% probability. The phase of maximum strain rate in the 12.4 h M2 period coincides with the phase of the maximum tremor rate taken from a catalog in an overlapping region. Comparison with a simple tidal loading model shows that the phase of maximum strain rate in the M2 period may occur at the maximum shear stress or up to 90° before it, depending on the location of slip in the subduction zone.
Tissue‐specific calibration of extracellular matrix material properties by transforming growth factor‐β and Runx2 in bone is required for hearing
Authors: Chang Jolie L , Brauer Delia S , Johnson Jacob , Chen Carol G , Akil Omar , Balooch Guive , Humphrey Mary Beth , Chin Emily N , Porter Alexandra E , Butcher Kristin , Ritchie Robert O , Schneider Richard A , Lalwani Anil , Derynck Rik , Marshall Grayson W , Marshall Sally J , Lustig Lawrence , Alliston Tamara
Published: September 2010

Physical cues, such as extracellular matrix stiffness, direct cell differentiation and support tissue‐specific function. Perturbation of these cues underlies diverse pathologies, including osteoarthritis, cardiovascular disease and cancer. However, the molecular mechanisms that establish tissue‐specific material properties and link them to healthy tissue function are unknown. We show that Runx2, a key lineage‐specific transcription factor, regulates the material properties of bone matrix through the same transforming growth factor‐β (TGFβ)‐responsive pathway that controls osteoblast differentiation. Deregulated TGFβ or Runx2 function compromises the distinctly hard cochlear bone matrix and causes hearing loss, as seen in human cleidocranial dysplasia. In Runx2+/− mice, inhibition of TGFβ signalling rescues both the material properties of the defective matrix, and hearing. This study elucidates the unknown cause of hearing loss in cleidocranial dysplasia, and demonstrates that a molecular pathway controlling cell differentiation also defines material properties of extracellular matrix. Furthermore, our results suggest that the careful regulation of these properties is essential for healthy tissue function.
Chelation of lysosomal iron protects against ionizing radiation
Authors: Berndt Carsten , Kurz Tino , Selenius Markus , Fernandes Aristi P. , Edgren Margareta R. , Brunk Ulf T.
Published: September 2010

Ionizing radiation causes DNA damage and consequent apoptosis, mainly due to the production of hydroxyl radicals (HO•) that follows radiolytic splitting of water. However, superoxide (O2•−) and H2O2 also form and induce oxidative stress with resulting LMP (lysosomal membrane permeabilization) arising from iron-catalysed oxidative events. The latter will contribute significantly to radiation-induced cell death and its degree largely depends on the quantities of lysosomal redox-active iron present as a consequence of autophagy and endocytosis of iron-rich compounds. Therefore radiation sensitivity might be depressed by lysosome-targeted iron chelators. In the present study, we have shown that cells in culture are significantly protected from ionizing radiation damage if initially exposed to the lipophilic iron chelator SIH (salicylaldehyde isonicotinoyl hydrazone), and that this effect is based on SIH-dependent lysosomal stabilization against oxidative stress. According to its dose-response-modifying effect, SIH is a most powerful radioprotector and a promising candidate for clinical application, mainly to reduce the radiation sensitivity of normal tissue. We propose, as an example, that inhalation of SIH before each irradiation session by patients undergoing treatment for lung malignancies would protect normally aerated lung tissue against life-threatening pulmonary fibrosis, whereas the sensitivity of malignant lung tumours, which usually are non-aerated, will not be affected by inhaled SIH.
Compensation effect and differential capacitance analysis of electronic energy band structure in relaxed InAs quantum dots
Authors: Chen J. F. , Chen Ross C. C. , Chiang C. H. , Hsieh M. C. , Chang Y. C. , Chen Y. F.
Published: September 2010

The use of a differential capacitance technique for analyzing the effect of strain relaxation on the electronic energy band structure in relaxed InAs self-assembled quantum dots (QDs) is presented. Strain relaxation is shown to induce a deep defect state and compensate the ionized impurity in the bottom GaAs layer, leading to a double depletion width and a long emission time. An expression of capacitance at different frequency and voltage is derived for analyzing the experimental data. It has been shown that the relationship between the low-frequency and high-frequency capacitances can be well explained by a Schottky depletion model with a compensated concentration in the bottom GaAs layer. A simple expression is presented to account for the modulation of the free electrons in the top GaAs layer. This capacitance analysis shows a long low-energy tail for the electron ground state, suggesting not very uniform strain relaxation. The results of this study illustrate a carrier compensation effect of the defect state on the electronic energy band structure near the QDs.
The explanation of barrier height inhomogeneities in Au/n-Si Schottky barrier diodes with organic thin interfacial layer
Authors: Taşçıoğlu İlke , Aydemir Umut , Altındal Şemsettin
Published: September 2010

The forward bias current-voltage (I-V) characteristics of Au/n-Si Schottky barrier diodes (SBDs) with Zn doped poly(vinyl alcohol) (PVA:Zn) interfacial layer have been investigated in the wide temperature range of 80–400 K. The conventional Richardson plot of the ln(Io/T2) versus q/kT has two linear regions: the first region (200–400 K) and the second region (80–170 K). The values of activation energy (Ea) and Richardson constant (A∗) were obtained from this plot and especially the values of A∗ are much lower than the known theoretical value for n-type Si. Also the value of Ea is almost equal to the half of the band gap energy of Si. Therefore, the Φap versus q/2kT plot was drawn to obtain the evidence of a Gaussian distribution (GD) of barrier heights (BHs) and it shows two linear region similar to ln(Io)/T2 versus q/kT plot. The analysis of I-V data based on thermionic emission of the Au/PVA:Zn/n-Si SBDs has revealed the existence of double GD with mean BH values (Φ¯B0) of 1.06 eV and 0.86 eV with standard deviation (σ) of 0.110 eV and 0.087 V, respectively. Thus, we modified ln(Io/T2)−(qσ)2/2(kT)2 versus q/kT plot for two temperature regions (200–400 K and 80–170 K) and it gives renewed mean BHs Φ¯B0 values as 1.06 eV and 0.85 eV with Richardson constant (A∗) values 121 A/cm2 K2 and 80.4 A/cm2 K2, respectively. This obtained value of A∗=121 A/cm2 K2 is very close to the known theoretical value of 120 A/cm2 K2 for n-type Si.
Size-dependent spin state and ferromagnetism in La0.8Ca0.2CoO3 nanoparticles
Authors: Fita I. , Markovich V. , Wisniewski A. , Mogilyansky D. , Puzniak R. , Iwanowski P. , Meshi L. , Titelman L. , Varyukhin V. N. , Gorodetsky G.
Published: September 2010

Magnetic and structural properties of nanocrystalline low-doped La0.8Ca0.2CoO3 cobaltites with particle size of 8, 13, 23, and 50 nm, prepared by the glycine-nitrate method, were investigated in temperature range 5–320 K, magnetic field up to 50 kOe and under hydrostatic pressure up to 10 kbar. With particle downsizing, a noticeable expansion of unit cell, with concomitant changes in the rhombohedral structure toward the cubic one was observed. It was found that the increased surface-disorder effect strongly suppresses the ferromagnetic state in La0.8Ca0.2CoO3 nanoparticles leading to a decrease, by factor of about 2, both in spontaneous magnetization, MS, and Curie temperature, TC, when particle’s size decreases from 23 to 8 nm. The effective magnetic moment μeff was found also to decrease distinctly due to the strong interdependence between Co–O–Co interactions and Co spin state. The size-induced magnetic disorder drives the La0.8Ca0.2CoO3 nanoparticles to a dominant glassy behavior for 8 nm particles. This is evidenced by the fact that the freezing temperature varies with magnetic field in a strict conformity with the de Almeida–Thouless law for spin glasses and also by the observation of characteristic slowing down in the spin dynamics. The applied pressure suppresses TC, MS, and coercive field HC, like it is observed for bulk La0.8Ca0.2CoO3. Nevertheless, in nanoparticles the pressure effect on TC is noticeably stronger, while HC diminishes with pressure much slower then in bulk material.
Insight on the SU-8 resist as passivation layer for transparent Ga2O3–In2O3–ZnO thin-film transistors
Authors: Olziersky Antonis , Barquinha Pedro , Vilà Anna , Pereira Luís , Gonçalves Gonçalo , Fortunato Elvira , Martins Rodrigo , Morante Juan R.
Published: September 2010

A nonvacuum and low temperature process for passivating transparent metal oxides based thin-film transistors is presented. This process uses the epoxy-based SU-8 resist which prevents device degradation against environmental conditions, vacuum or sputtering surface damage. The incorporation of SU-8 as a passivation layer is based on the ability of this polymer to provide features with high mechanical and chemical stability. With this approach, lithography is performed to pattern the resist over the active area of the device in order to form the passivation layer. The resulting transistors demonstrate very good electrical characteristics, such as μFE=61 cm2/V s, VON=−3 V, ON/OFF=4.4×109, and S=0.28 V/dec. Electrical behavior due to the SU-8/metal oxide interface characteristics is also reported on the basis of Fourier transform infrared analysis. In contrast, we demonstrate how sputtering of SiO2 as a passivation layer results in severely degraded devices that cannot be switched-off. In order to obtain proper working devices, it is shown that SU-8 should be hard baked at 200 °C for 1 h in order to obtain a highly cross-linked polymer network. The stability of SU-8 passivated devices over the time of storage, under current bias stress and vacuum conditions is also demonstrated.
Determination of limiting factors of photovoltaic efficiency in quantum dot sensitized solar cells: Correlation between cell performance and structural properties
Authors: Giménez Sixto , Lana-Villarreal Teresa , Gómez Roberto , Agouram Said , Muñoz-Sanjosé V. , Mora-Seró Iván
Published: September 2010

Semiconductor quantum dots (QDs) are important candidates as light absorbing materials in low cost and high efficiency sensitized solar cells (SCs). We present a combination of structural, chemical, electrical, and optical characterization that provides insight to the photovoltaic efficiencies of devices formed by TiO2 electron conducting oxide network sensitized with CdSe. In devices using colloidal QDs the collection efficiency under short circuit conditions (CESCs) for photoinjected electrons is rather high (∼90%) but the photovoltaic performance is limited by the low loading of QDs into the mesoporous TiO2 structure. On the other hand, chemical bath deposited (CBD) QDSCs exhibit a remarkably high optical density, but only slightly higher short circuit current and efficiency. It is observed that CESC is ∼50% due to the high recombination rates of the closed packed QDs structure. Our results indicate routes for improvement of QDSCs performance by the increase in colloidal QDs loading and the reduction in recombination in QDs grown in situ.
Spin-flip time dependent density functional theory applied to excited states with single, double, or mixed electron excitation character
Authors: Rinkevicius Zilvinas , Vahtras Olav , Ågren Hans
Published: September 2010

We analyze the ability of spin-flip time dependent density functional theory (TD-DFT) to uniformly describe excited states of single, double, and mixed excitation character in closed-shell molecular systems, using the polyene oligomers as a primary test case. The results of comparison between conventional and spin-flip TD-DFT and with correlated ab initio methods indicate that spin-flip TD-DFT provides a more consistent description of the ordering and relative positions of the excited states than conventional TD-DFT provided a suitable exchange-correlation functional is used in the calculations. It is found that spin-flip TD-DFT provides a physically appealing picture of excitation processes which involve one or two electrons, as it captures their most important features and facilitates a more uniform description of excited states with different character. This makes spin-flip TD-DFT a promising approach for general modeling of excited states and spectra of medium and large size molecules, which exhibit low-lying excited states with strong double excitation character.
A novel cylindrical TE2,1 mode converter
Authors: Constable D. A. , Fampris X. S. , Ronald K. , He W. , Whyte C. G. , Robertson C. W.
Published: September 2010

A novel, compact arrangement for Ka-band mode couplers, which convert a rectangular waveguide TE1,0 to cylindrical waveguide TE2,1 mode, has been designed, constructed, and tested. The design features a set of longitudinal slots, positioned in regions of negligible current flow for the TE2,1 mode, allowing its propagation to be preferentially favored, by suppression of the fundamental TE1,1 mode. Numerical simulations and experimental measurements display good agreement, showing transmission of the intended TE2,1 mode at levels of better than −5 dB, from a frequency of ∼37.5 to 41 GHz. Subsequent farfield measurements confirm the presence of the TE2,1 mode, demonstrating good agreement when compared with analytical expectations. Such a device would be an ideal candidate for an application where mode purity, bandwidth, and ease of construction are of primary importance and where the transmission efficiency is of limited concern.
Analysis for piezoresistive property of heavily-doped polysilicon with upper and lower bounds
Authors: Matsuzuka Naoki , Toriyama Toshiyuki
Published: September 2010

This paper proposed an analysis for the piezoresistive property of heavily-doped polycrystalline silicon (polysilicon) with upper and lower bounds derived using the fundamental piezoresistive coefficients of single-crystalline silicon (SCS). The analysis is applicable to the polysilicon that the piezoresistive effect in grain boundaries is negligible and the orientations of the SCS grains are completely random. For deriving the upper and lower bounds, the analysis employed two approximation models on the basis of two extreme assumptions of uniform stress and fractional change in resistivity in each SCS grain of polysilicon. The fundamental piezoresistive coefficients of polysilicon derived from these models were successfully defined as the upper and lower bounds, based on the elastic theories in the micromechanics filed. The applicability of the analysis was discussed by comparing the derived upper and lower bounds with the piezoresistive property of heavily-doped polysilicon measured in some previous works. The measured piezoresistive property of both p-type and n-type polysilicon lay within the theoretical possible range between the upper and lower bounds at the impurity concentration of 1019 cm−3 levels, which suggested the applicability of the proposed analysis for the piezoresistive property of heavily-doped polysilicon.
Pattern formation controlled by time-delayed feedback in bistable media
Authors: He Ya-Feng , Ai Bao-Quan , Hu Bambi
Published: September 2010

Effects of time-delayed feedback on pattern formation are studied both numerically and theoretically in a bistable reaction-diffusion model. The time-delayed feedback applied to the activator and/or the inhibitor alters the behavior of the nonequilibrium Ising–Bloch (NIB) bifurcation. If the intensities of the feedbacks applied to the two species are identical, only the velocities of Bloch fronts are changed. If the intensities are different, both the critical point of the NIB bifurcation and the threshold of stability of front to transverse perturbations are changed. The effect of time-delayed feedback on the activator opposes the effect of time-delayed feedback on the inhibitor. When the time-delayed feedback is applied individually to one of the species, positive and negative feedbacks make the bifurcation point shift to different directions. The time-delayed feedback provides a flexible way to control the NIB bifurcation and the pattern formation.
Note: Synchronized stress-strain measurements in dynamic loading at high pressure using D-DIA
Authors: Li Li , Weidner Donald J.
Published: September 2010

A new data collection protocol for forced oscillation experiments using a multianvil high pressure device is reported. We derive the stress of the sample at high pressure and temperature from synchrotron x-ray diffraction that is synchronized with sample strain measurements from x-ray radiographs. This method yields stress directly from the sample rather than a stress proxy. Furthermore, the diffraction pattern yields useful information concerning time evolution of structurally related phenomena. Here we illustrate some of these possibilities with high pressure experimental data.
Topological effect on thermal conductivity in graphene
Authors: Jiang Jin-Wu , Wang Jian-Sheng , Li Baowen
Published: September 2010

The topological effect on thermal conductivity is investigated through the comparison among graphene nanoribbons, carbon nanorings, and the Möbius-like graphene strips (MGS) by molecular dynamics simulation. It is found that the thermal conductivity of MGS is less than one half of that of graphene nanoribbons. The underlying mechanism whereby MGS acquire such low thermal conductivity may be attributable to the enhanced phonon-phonon scattering and localization property, which are induced by the nontrivial topology of Möbius strip. Moreover, by counting in the dimensions of MGS, a lower length/width ratio reduces its thermal conductivity, as the phonon-phonon scattering and localization within might be further elevated.
Computation of two-dimensional electric field from the ion laser induced fluorescence measurements
Authors: Spektor Rostislav
Published: September 2010

This paper presents a method of computing two-dimensional electric field from ion laser induced fluorescence (LIF) measurements in a plasma flow. The expression for the field is derived by taking velocity moments of the Boltzmann equation for ions. It was found that the pressure tensor, related to the width of the ion velocity distribution, plays a critical role in the computation of the electric field. Even with the assumption of cold ion flow, the pressure tensor contribution may be significant when velocity spread is caused by other forces. Such a situation occurs in the flow of a Hall thruster, where velocity spread is caused by the ions born at different potentials. LIF measurements of the cylindrical hall thruster plume were used to demonstrate practical application of the derived method. Whenever the pressure tensor components are small as compared to the mean ion drift velocity, the electric field calculations reduce to a simple expression given in terms of mean ion drift velocity and its divergence.
Measurement of nanoscale external quantum efficiency of conjugated polymer:fullerene solar cells by photoconductive atomic force microscopy
Authors: Dang Xuan-Dung , Mikhailovsky Alexander , Nguyen Thuc-Quyen
Published: September 2010

Photoconductive atomic force microscopy is used to investigate nanoscale incident photon-to-current efficiency spectra of polymer bulk heterojunction solar cells based on poly[2-methoxy-5-(3,7-dimethyloctyloxy)]-1,4-phenylenevinylene (MDMO-PPV) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM). Nanoscale external quantum efficiency reveals the complex morphology of MDMO-PPV:PC71BM films cast from toluene solution. Not only electron transfer from the photoexcited donor to the fullerene but also hole transfer process from photoexcited fullerene to the donor phase due to highest occupied molecular orbital offset is observed. The difference in performance between toluene and chlorobenzene-cast devices is explained by the variation in relative contributions from two charge transfer mechanisms.
Demonstration of single-flux-quantum readout operation for superconducting single-photon detectors
Authors: Terai Hirotaka , Miki Shigehito , Yamashita Taro , Makise Kazumasa , Wang Zhen
Published: September 2010

A readout circuit using superconducting single-flux-quantum (SFQ) circuits has been developed to realize an independently addressable array of superconducting single-photon detectors (SSPDs). We tested the SFQ readout circuits by connecting with SSPDs. The error rates of readout circuits were below 10−5 for input signal amplitude of greater than 18.2 μA. Detection efficiencies (DEs) for single-photon incidents were measured both with and without the connection of a readout circuit. The observed DEs traced almost the same curves regardless of the connection of the readout circuit, except that the SSPD is likely to latch by connecting the readout circuit.
Exact partition function zeros and the collapse transition of a two-dimensional lattice polymer
Authors: Lee Jae Hwan , Kim Seung-Yeon , Lee Julian
Published: September 2010

We study the collapse transition of the lattice homopolymer on a square lattice by calculating the exact partition function zeros. The exact partition function is obtained by enumerating the number of possible conformations for each energy value, and the exact distributions of the partition function zeros are found in the complex temperature plane by solving a polynomial equation. We observe that the locus of zeros closes in on the positive real axis as the chain length increases, providing the evidence for the onset of the collapse transition. By analyzing the scaling behavior of the first zero with the polymer length, we estimate the transition temperature Tθ and the crossover exponent ϕ.
Nonlinearity and scaling behavior in a soft lead zirconate titanate piezoceramic
Authors: Hajjaji Abdelowahed , Guyomar Daniel , Touhtouh Samira , Pruvost Sebastien , Boughaleb Yahia , Rguiti Mohamed , Courtois Christian , Leriche Anne , Benkhouja Khalil
Published: September 2010

Lead oxide-based ferroelectrics, represented by lead zirconate titanate [Pb(Zr,Ti)O3] or PZT), are the most widely used materials for piezoelectric actuators, sensors, and transducers due to their excellent piezoelectric properties. Most of these piezoelectric materials are employed under a variety of strains (stress, electrical field, and temperature). It would thus be interesting to predict their behaviors under different excitations without having to perform too much experimental work, i.e., just carry out a single experiment and still be able to provide the other experimental values. The purpose of this paper has thus been to propose several behavioral laws linking the electrical field, temperature and mechanical stress. The first law rendered it possible to express the mechanical stress by an equivalent electric field [ΔE≡αΔT×P(E,T0)]. Subsequently, a law linking the electrical field and temperature {ΔE≡[2β×P(E,θ0)]×Δθ} was proposed. From these two laws, a third law was identified reflecting the mechanical stress as an equivalent temperature; each expressed by a temperature equivalent stress (T≡δ×Δθ). After experimental validation of these laws, the mapping could be extended in order to predict the polarization behavior in the tensile stress zone as well as that as a function of the negative temperature.
Giant low frequency dielectric tunability in high-k Ba(Fe1/2Nb1/2)O3 ceramics at room temperature
Authors: Ke Shanming , Huang Haitao
Published: September 2010

The effect of electric field on the dielectric properties of high-k Ba(Fe1/2Nb1/2)O3 ceramics with different grain sizes is reported. A low frequency giant dielectric tunability (>85%) can be obtained under a bias field as low as 50 V/mm. The results suggest that the giant dielectric tunability originates from extrinsic contributions such as domain boundary and oxygen defect relaxations. These findings provide a clear understanding to the complicated dielectric response in a family of high-k ceramics and a key to the high tunability of nonferroelectrics under low electric fields, which is attractive for potential applications in tunable devices.
Transmission electron microscopy and in situ Raman studies of glassy sanbornite: An insight into nucleation trend and its relation to structural variation
Authors: Takahashi Yoshihiro , Osada Minoru , Masai Hirokazu , Fujiwara Takumi
Published: September 2010

In situ observation of Raman scattering in glassy sanbornite (BaSi2O5) showing homogeneous nucleation was performed during heating to investigate the structural variation in the glassy/supercooled-liquid phase in the pre- and postnucleation regimes. It was observed that the formation of Q2 units accelerates around 400 °C, which is well below Tg, just after structural relaxation in the Ba-enriched/-cohesive region. The relation between the structural variation and the nucleation trend in glassy sanbornite was also discussed on the basis of transmission electron microscopy and in situ Raman results and previous Boson observation [Takahashi et al. Appl. Phys. Lett. 94, 211907 (2009)].
Three-dimensional ferroelectric domain imaging of epitaxial BiFeO3 thin films using angle-resolved piezoresponse force microscopy
Authors: Park Moonkyu , Hong Seungbum , Klug Jeffrey A. , Bedzyk Michael J. , Auciello Orlando , No Kwangsoo , Petford-Long Amanda
Published: September 2010

Here we introduce angle-resolved piezoresponse force microscopy (AR-PFM), whereby the sample is rotated by 30° increments around the surface normal vector and the in-plane PFM phase signals are collected at each angle. We obtained the AR-PFM images of BaTiO3 single crystal and cube-on-cube epitaxial (001) BiFeO3 (BFO) thin film on SrRuO3/SrTiO3 substrate, and confirmed that the AR-PFM provides more unambiguous information on the in-plane polarization directions than the conventional PFM method. Moreover, we found eight additional in-plane polarization variants in epitaxial BFO thin films, which are formed to mitigate highly unstable charged domain boundaries.
Manipulating magnetic moment in a magnetic domain wall under transverse magnetic fields near Walker threshold
Authors: Jang Youngman , Yoon Seungha , Lee Seungkyo , Lee Kisu , Cho B. K.
Published: September 2010

Current-induced domain wall (DW) motion under transverse magnetic fields was investigated through micromagnetic simulation using the Landau–Lifshitz–Gilbert equation containing adiabatic and nonadiabatic spin torque terms. It was found that the transverse field aligned antiparallel to the magnetic moment of the DW promotes a nucleation of an antivortex core, which causes a temporal Walker breakdown and then causes the magnetic moment of the DW to be aligned parallel to the transverse field. On the other hand, the transverse field aligned parallel to the magnetic moment of the DW induces the nucleation of an antivortex core at an edge of a nanowire to be delayed, resulting in the increase in Walker threshold current. The effect of transverse field on current-induced DW motion should be considered carefully for the spintronic applications that utilize DW motion.
Electronic spectra of Yb2+-doped SrCl2
Authors: Sánchez-Sanz Goar , Seijo Luis , Barandiarán Zoila
Published: September 2010

The absorption and emission spectra of Yb2+-doped SrCl2 have been calculated on the basis of ab initio quantum chemical calculations which consider recently found, unexpected excited states with double-well energy curves and complex electronic structure, resulting from avoided crossings between Yb-trapped excitons and Yb impurity states, which influence prominent spectral features. The root mean square deviation and largest absolute error of the calculated energy levels are 394 and −826 cm−1, respectively. The YbCl8 moiety breathing mode vibrational frequencies and bond lengths of the lowest states are consistent with observed vibrational progressions and energy shifts induced by uniaxial compression. Photoionization is predicted above 49 000 cm−1 as a consequence of the spin-orbit induced spreading of the Yb-trapped exciton character in the upper part of the spectrum and three new emission bands are predicted with origins at about 33 800, 36 400, and 43 600 cm−1. The electron correlation methods used overestimate the relative stabilization of the 4f14 ground state and this leads to a constant error of the whole absorption spectrum of about 3500 cm−1 (23%–7%). Although this energy shift is customarily considered an adjustable parameter, it is a nonparametric, direct product in an ab initio route which shows the limitations on the proper representation of differential correlation between the 4fN and 4fN−15d (or similar) configurations and the need for theoretical improvement.
Enhanced color conversion from colloidal CdSe/CdS dot/rods by vertical microcavities
Authors: Pühringer H. , Roither J. , Kovalenko M. V. , Eibelhuber M. , Schwarzl T. , Talapin D. V. , Heiss W.
Published: September 2010

Colloidal CdSe/CdS dot/rods exhibit efficient photoluminescence from the spherical CdSe dots at wavelengths well below the absorption edge of the rod material. This property makes dot/rods advantageous for color conversion applications, especially when they are embedded in optical microcavities to improve light extraction in forward direction. Here, surface emitting half-wavelength microcavities are demonstrated containing films of dot/rods as active material, exhibiting luminescence enhancement factors of up to 21 at the resonator wavelengths, whereas with conventional CdSe/ZnS core-shell nanocrystals only half of this value is obtained.