bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactivity of acenes: mechanisms and dependence on acene length
Authors: Zade Sanjio S. , Bendikov Michael
Published: January 2012

Acenes are polycyclic aromatic hydrocarbons consisting of linearly fused benzene rings. These compounds are currently the subject of great interest from both fundamental and applied perspectives, particularly for use in organic electronics. This review highlights the computational studies carried out to understand acene reactivity, their reaction mechanisms, and the relationship of the latter to acene length. Generally, as acene length increases, the reactivity of acenes increases, and a greater tendency towards a biradical mechanism is observed. For example, an interesting change in mechanism (from concerted to biradical) is observed for the reaction of acenes (benzene through pentacene) with molecular oxygen. A computational study of the addition of HCl (which behaves as an electrophile) and water (which behaves mostly as a nucleophile) to acenes revealed that acene reactivity increases along the series up to hexacene and remains constant from hexacene and above because of the biradical character of the ground state of higher acenes. Although the exothermicity of the addition of water and HCl to acene is similar, the activation barrier for the addition of water is significantly higher than that for HCl. There is a substantial substituent effect on the energy barriers for electrophilic and nucleophilic reactions. Phenyl substitution at the most reactive meso‐carbon atoms of the central ring of acene blocks dimerization through this ring but does not efficiently prevent dimerization through other rings. With respect to the self‐reactivity (such as dimerization, etc.) of acenes, a computational study showed that the preferred pathways are the formation of acene dimers via a central benzene ring and the formation of acene‐based polymers. Interestingly, longer acenes are predicted to self‐react to form polymers, rather than acene dimers, as the thermodynamically preferred product. These findings invite experimentalists to reinvestigate the dimerization of long unsubstituted acenes. Given that computational studies directly relate to the gas phase reactivity of acenes, whereas long acenes find application in organic semiconductor devices as solids, the next research challenge is to obtain an understanding of the solid state reactivity of long acenes. Copyright © 2012 John Wiley & Sons, Ltd.
Household Members' Migration and the Education of Children ‘Left Behind’: Empirical Findings from Tajikistan and Reflections for Research Practice
Authors: Bennett Rachel , Clifford David , Falkingham Jane
Published: January 2012

There is growing recognition that when a household member migrates, there is a complex range of social as well as economic consequences for the everyday lives of those who remain in the origin household. This paper examines the children left behind phenomenon in Tajikistan, a country with very high rates of international labour migration. With the use of data from the Tajikistan 2007 Living Standards Survey, logistic regression modelling is applied to examine the impact of fathers', mothers', siblings', and other household members' migration on the school enrolment of secondary school‐aged children. The results show that there is a significant positive association between longer‐term parental migration and children's enrolment, whereas the long‐term migration of siblings sending remittances and the mid‐term migration of ‘other household members’ (not parents or siblings) are both significantly negatively associated with children's enrolment. The findings highlight the importance of considering differences between children left behind. Copyright © 2012 John Wiley & Sons, Ltd.
A Genetic‐Based Iterative Quantile Regression Algorithm for Analyzing Fatigue Curves
Authors: Park Jong In , Kim Norman , Bae Suk Joo
Published: January 2012

Accurate prediction of fatigue failure times of materials such as fracture and plastic deformation at various stress ranges has a strong bearing on practical fatigue design of materials. In this study, we propose a novel genetic‐based iterative quantile regression (GA‐IQR) algorithm for analyzing fatigue curves that represent a nonlinear relationship between a given stress amplitude and fatigue life. We reduce the problem to a linear framework and develop the iterative algorithm for determining the model coefficients including unknown fatigue limits. The procedure keeps updating the estimates in a direction to reduce its resulting error. Also, our approach benefits from the population‐based stochastic search of the genetic algorithms so that the algorithm becomes less sensitive to its initialization. Compared with conventional approaches, the proposed GA‐IQR requires fewer assumptions to develop fatigue model, capable of exploring the data structure in a relatively flexible manner. All procedures and calculations are quite straightforward, such that the proposed quantile regression model has a high potential value in a wide range of applications for exploring nonlinear relationships with lifetime data. Computational results for real data sets found in the literature present good evidences to support the argument. Copyright © 2012 John Wiley & Sons, Ltd.
Reliability‐Based Design Optimization Considering Probabilistic Degradation Behavior
Authors: Rathod Vijay , Yadav Om Prakash , Rathore Ajay , Jain Rakesh
Published: January 2012

This article proposes a reliability‐based design optimization methodology by incorporating probabilistic degradation in the fatigue resistance of material. The probabilistic damage accumulation is treated as a measure of degradation in the fatigue resistance of material and modeled as nonstationary probabilistic process to capture the time‐dependent distribution parameters of damage accumulation. The proposed probabilistic damage accumulation model is then incorporated into reliability‐based design optimization model by building a dynamic reliability model inferred from the stress–strength interference model. The proposed approach facilitates to capture the dynamic degradation behavior while optimizing design variables at an early design stage to improve the overall reliability of product. The applicability of the proposed approach is demonstrated using suitable examples. Copyright © 2012 John Wiley & Sons, Ltd.
On the Monitoring of Simple Linear Berkson Profiles
Authors: Wang Yi‐Hua Tina , Huwang Longcheen
Published: January 2012

We consider the quality of a process, which can be characterized by a simple linear Berkson profile. One existing approach for monitoring the simple linear profile and two new proposed schemes are studied for charting the simple linear Berkson profile. Simulation studies demonstrate the effectiveness and efficiency of one of the proposed monitoring schemes. In addition, a systematic diagnostic approach is provided to spot the change point location of the process and to identify the parameter of change in the profile. Finally, an example from semiconductor manufacturing is used to illustrate the implementation of the proposed monitoring scheme and diagnostic approach. Copyright © 2012 John Wiley & Sons, Ltd.
Variable Sample Size and Sampling Interval Charts with Runs Rules for Switching Between Sample Sizes and Sampling Interval Lengths
Authors: Mahadik Shashibhushan B.
Published: January 2012

Variable sample size and sampling interval (VSSI) charts are substantially more efficient than are the static charts. However, the frequent switches between sample sizes and sampling interval lengths can be a complicating factor during the implementation of these charts. In this article, runs rules are proposed for switching between the sample sizes and the sampling interval lengths of these charts to reduce the frequency of switches. The expressions for the performance measures for the charts with these runs rules are developed. The methods presented are general and can be applied to other VSSI Shewhart control charts. The effects of different runs rules on the performances of the charts are compared numerically. The runs rules substantially reduce the frequency of switches. Some runs rules do not significantly alter the statistical performances of the charts; however, some adversely affect that in detecting large shifts in the process mean. Copyright © 2012 John Wiley & Sons, Ltd.
Determination of CLA trans,trans Positional Isomerism in CLA‐Rich Soy Oil by GC–MS and Silver Ion HPLC
Authors: Shah Utkarsh , Proctor Andrew , Lay Jackson O. , Moon Kwangyul
Published: January 2012

A ~20% CLA‐rich soy oil with low saturated fat and no cholesterol was produced by photoisomerizing soy oil linoleic acid. The oil is predominately trans,trans CLA, with the oil containing 17% trans,trans CLA. Recent studies have shown that trans,trans CLA‐rich soy oil significantly reduces heart disease and diabetes risk factors in obese rats. However, the positional isomerism of these geometrical isomers has not been identified. The objectives of the study were to determine trans,trans CLA positional isomerism of CLA fatty acids in CLA‐rich soy oil and determine the resolution of trans,trans CLA positional isomers by silver ion chromatography. GC–MS studies of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD) derivatives of CLA‐rich oil showed that 9,11 CLA and 10,12 CLA were the major positional isomers. These were hypothesized to be the trans,trans CLA isomers, which was confirmed by silver ion chromatography and subsequent GC–FID fatty acid and ATR‐FTIR geometrical isomer analysis of the collected fractions. The identification of 9,11 trans,trans CLA and 10,12 trans,trans CLA as the major CLA isomers in CLA‐rich oil then allowed the deduction of the synthetic mechanism of the photoisomerism of soy oil linoleic acid to trans,trans CLA.
VapB as a regulator of osteoclastogenesis via modulation of PLCγ2‐Ca2+‐NFAT signaling
Authors: Choi Sik-Won , Yeon Jeong-Tae , Park Kie-In , Lee Chang Hoon , Youn Byung Soo , Oh Jaemin , Lee Myeung Su
Published: January 2012

VapB has been shown to regulate calcium homeostasis in amyotrophic lateral sclerosis. Calcium signaling is also important in metabolic bone diseases, but the role of VapB in the generation of osteoclasts for bone resorption during osteoclastogenesis is not known. Therefore, we investigated the role of VapB in RANKL‐induced osteoclast differentiation. Interestingly, VapB is induced during osteoclastogenesis, and regulates osteoclast differentiation by modulating NFATc1. The results also suggest that VapB regulates osteoclastogenesis via PLCγ2‐Ca2+‐NFAT signaling. The involvement of PLCγ2‐Ca2+‐NFAT signaling in VapB‐regulated osteoclastogenesis was confirmed by a pharmacological study. Taken together, the results indicate that VapB positively regulates RANKL‐mediated osteoclastogenesis via PLCγ2‐Ca2+‐NFAT signaling.
Identification and characterization of an LCAT‐like Arabidopsis thaliana gene encoding a novel phospholipase A
Authors: Chen Guanqun , Greer Michael S. , Lager Ida , Lindberg Yilmaz Jenny , Mietkiewska Elzbieta , Carlsson Anders S. , Stymne Sten , Weselake Randall J.
Published: January 2012

A previously uncharacterized Arabidopsis lecithin:cholesterol acyltransferase (LCAT) family gene (At4g19860) was functionally expressed in yeast, where it was demonstrated to encode a novel cytosolic and calcium‐independent phospholipase A with preferences for the sn‐2 position. This enzyme shows optimal activity at pH 5.0, exhibits a headgroup specificity for phosphatidylcholine > phosphatidic acid > phosphatidylethanolamine > phosphatidylglycerol > phosphatidylserine and has an acyl chain specificity for oleoyl > linoleoyl > ricinoleoyl. The expression of AtLCAT‐PLA inhibited yeast cell growth and fatty acid accumulation. AtLCAT‐PLA transcript in Arabidopsis was detected at high levels in roots and siliques.
Diphenyl diselenide diet intake improves spatial learning and memory deficits in hypothyroid female rats
Authors: Dias Glaecir Roseni Mundstock , Vieira Francielli Araújo , Dobrachinski Fernando , Bridi Jéssika Cristina , Balk Rodrigo de Souza , Soares Félix Antunes , Nogueira Cristina Wayne , Barbosa Nilda Berenice de Vargas
Published: January 2012

Cognitive deficits have been observed in different animal models of adult‐onset hypothyroidism. Thus, this study was delineated to evaluate whether diphenyl diselenide, an organoselenium compound with neuroprotective and antioxidant properties, could afford protection against the detrimental effects of hypothyroidism on behavioral parameters. Hypothyroidism condition was induced in female rats by continuous exposure to methimazole (MTZ) at 20 mg/100 ml in the drinking water, during 3 months. MTZ‐induced hypothyroid rats were fed with either standard or a diet containing 5 ppm of diphenyl diselenide for 3 months. Behavioral assessments were performed monthly, in the following order: elevated plus maze, open field and Morris water maze. The levels of thyroid hormones in the animals exposed to MTZ were lower than control until the end of experimental period. The rats exposed to MTZ had a significant weight loss from the first month, which was not modified by diphenyl diselenide supplementation. In elevated plus maze test, MTZ exposure caused a reduction on the number of entries of animals in closed arms, which was avoided by diphenyl diselenide supplementation. In Morris water maze, the parameters latency to reach the platform and distance performed to find the escape platform in the test session were significantly greater in MTZ group when compared to control. These cognitive deficits observed in MTZ‐induced hypothyroid rats were restored by dietary diphenyl diselenide. The group fed with diphenyl diselenide alone exhibited a better spatial learning and memory capability in some parameters of Morris water maze when compared to the control group. In summary, our data provide evidence of the effectiveness of dietary diphenyl diselenide in improving the performance of control and hypothyroid rats in the water maze test.
Physical exercise reverses glutamate uptake and oxidative stress effects of chronic homocysteine administration in the rat
Authors: da Cunha Maira J. , da Cunha Aline A. , Ferreira Andréa G.K. , Machado Fernanda R. , Schmitz Felipe , Lima Daniela D. , Delwing Debora , Mussulini Ben Hur M. , Wofchuk Susana , Netto Carlos A. , Wyse Angela T.S.
Published: January 2012

The influence of physical exercise on the effects elicited by homocysteine on glutamate uptake and some parameters of oxidative stress, namely thiobarbituric acid‐reactive substances, 2′,7′‐dichlorofluorescein (H2DCF) oxidation, as well as enzymatic antioxidant activities, superoxide dismutase, catalase and glutathione peroxidase in rat cerebral cortex were investigated. Wistar rats received subcutaneous administration of homocysteine or saline (control) from the 6th to 29th day of life. The physical exercise was performed from the 30th to 60th day of life; 12 h after the last exercise session animals were sacrificed and the cerebral cortex was dissected out. It is shown that homocysteine reduces glutamate uptake increases thiobarbituric acid‐reactive substances and disrupts enzymatic antioxidant defenses in cerebral cortex. Physical activity reversed the homocysteine effects on glutamate uptake and on antioxidant enzymes activities; although the increase in thiobarbituric acid‐reactive substances was only partially reversed by exercise. These findings allow us to suggest that physical exercise may have a protective role against homocysteine‐induced oxidative imbalance and brain damage to the glutamatergic system.
Entrainment and mixing dynamics of surface-stress-driven stratified flow in a cylinder
Authors: Shravat A. , Cenedese C. , Caulfield C. P.
Published: January 2012

We extend previous work of Boyer, Davies & Guo (Fluid Dyn. Res., vol. 21, 1997, pp. 381–401) to consider the evolution of an initially two-layer stratified fluid in a cylindrical tank which is driven by a horizontal rotating disk. The turbulent motions induced by the disk drive entrainment at the interface, and similarly to the results of Boyeret al. (1997), the layer nearer to the disk deepens. Through high-frequency conductivity probe measurements, we establish that the deepening layer is very well-mixed, and the thickness of the interface between the two evolving layers appears to be approximately constant. Under certain circumstances, we find that the rate of increase in depth of the deepening layer decreases with time, at variance with the results of Boyeret al. (1997), and implying that the characteristic velocity in the deepening layer decreases as the upper layer deepens. We propose that such time-dependent deepening, and the associated weakening of the upper-layer velocities, occurs naturally because of the combined power requirements of entrainment and layer homogenization which inhibit, when the stratification is very strong, the characteristic velocities of the deepening layer approaching the (constant) velocities of the driving disk, as assumed by Boyeret al. (1997).
Experimental investigation of nonlinear instabilities in annular liquid sheets
Authors: Duke D. , Honnery D. , Soria J.
Published: January 2012

The aerodynamically driven annular liquid sheet exhibits a complex nonlinear instability. Novel interfacial velocimetry experiments suggest that two distinct physical sources of instability may be present. The first is the well-known free shear layer instability, which is quasi-sinusoidal and nonlinear. The second is a distinct nonlinear rupturing instability, modulated on the previous one. It may be directly driving primary atomization. This instability has not been previously observed in isolation and is inherently nonlinear and non-sinusoidal. Novel application of Koopman analysis and the Hilbert transform permit investigation of these distinct instabilities. A greater understanding of the rupturing instability may lead to a better understanding of atomization phenomena.
Critical Realism: some responses
Authors: WIGHT COLIN
Published: January 2012

I would like to thank the editors for giving me the opportunity to respond to some of the criticisms raised in the forum on Critical Realism, or what is sometimes known as scientific realism (CR/SR). In this short response I shall attempt to correct some of the misunderstandings of Critical Realism in the forum, but also highlight a fundamental philosophical disagreement that has important political consequences.
Essentially exact asymptotic solutions for Asian derivatives
Authors: SIYANKO S.
Published: January 2012

In this paper, we will show how to obtain asymptotic solutions for the problem of pricing Asian options. Under the assumption that the underlying follows geometric Brownian motion, we will derive Taylor expansion series for the fixed and floating strike Asian options. While there will be no analytical formulae for calculating expansion coefficients, we will provide relatively simple algorithms for calculating them. The methodology is particularly effective for the case of continuously sampled fixed-strike Asian calls where it takes only seconds to obtain constants for the Taylor expansion series that can converge beyond 10 significant digits. It is needless to say that we need to calculate Taylor expansion constants only once and the option price would be an analytical expression constructed from a cumulative normal distribution function, an exponential function and finite sums.
Strength of the relationships between three self-reported dietary intake instruments and serum carotenoids: the Observing Energy and Protein Nutrition (OPEN) Study
Authors: George Stephanie M , Thompson Frances E , Midthune Douglas , Subar Amy F , Berrigan David , Schatzkin Arthur , Potischman Nancy
Published: January 2012

Objective

To assess the strength of the relationships between serum carotenoids and three self-reported dietary intake instruments often used to characterize carotenoid intake in studies of diet and disease.

Design

Participants completed a Diet History Questionnaire (DHQ), two 24 h dietary recalls (24HR), a fruit and vegetable screener and a fasting blood draw. We derived dietary intake estimates of α-carotene, β-carotene, cryptoxanthin, lutein, zeaxanthin and lycopene from each diet instrument and calculated sex-specific multivariate correlations between dietary intake estimates and their corresponding serum values.

Setting

Montgomery County, Maryland, USA.

Subjects

Four hundred and seventy women and men aged 40–69 years in the National Cancer Institute's Observing Protein and Energy Nutrition (OPEN) Study.

Results

Serum carotenoids correlated more strongly with the DHQ (r = 0·34–0·54 for women; r = 0·38–0·56 for men) than with the average of two recalls (r = 0·26–0·47 for women; r = 0·26–0·40 for men) with the exception of zeaxanthin, for which the correlations using recalls were higher. With adjustment for within-person variation, correlations between serum carotenoids and recalls were greatly improved (r = 0·38–0·83 for women; r = 0·42–0·74 for men). In most cases, correlations between serum carotenoids and the fruit and vegetable screener resembled serum–DHQ correlations.

Conclusions

Evidence from the study provides support for the use of the DHQ, a fruit and vegetable screener and deattenuated recalls for estimating carotenoid status in studies without serum measures, and draws attention to the importance of adjusting for intra-individual variability when using recalls to estimate carotenoid values.
If you stock it, will they buy it? Healthy food availability and customer purchasing behaviour within corner stores in Hartford, CT, USA
Authors: Martin Katie S , Havens Erin , Boyle Katie E , Matthews Gregory , Schilling Elizabeth A , Harel Ofer , Ferris Ann M
Published: January 2012

Objective

Literature on food environments has expanded rapidly, yet most research focuses on stores and community characteristics without integrating customer-level data. The present study combines customer shopping behaviour with store food inventory data.

Design

Face-to-face interviews were conducted with customers shopping in corner stores to measure food shopping behaviour, household food security and demographics. Store inventories were conducted to measure availability of healthy food in corner stores. Multilevel logistic regression models estimated the probability of customers purchasing a food item given the availability of that item in the store.

Setting

Nineteen corner stores in Hartford, CT, USA, average size 669 ft2 (62·15 m2).

Subjects

Sample of 372 customers.

Results

The majority of customers were Black or Hispanic (54 % and 40 %, respectively) and 61 % experienced food insecurity. For each additional type of fruits or vegetables available in the store, the estimated odds of a customer purchasing fruits increased by 12 % (P = 0·03) and the odds for purchasing vegetables increased by 15 % (P = 0·01). Customers receiving the Supplemental Nutrition Assistance Program (SNAP) were 1·7 times as likely to purchase fruit as those not receiving SNAP (P = 0·04). Greater availability of reduced-fat milk was not associated with increased likelihood of customers purchasing reduced-fat milk.

Conclusions

There is a positive association between fruit and vegetable variety and the probability that a customer purchases fruits and vegetables. Increasing the selection of produce in corner stores may increase their consumption by food-insecure and low-income residents at risk for health disparities. These findings have implications for future store interventions and food policies.
Conservation tillage issues: Cover crop-based organic rotational no-till grain production in the mid-Atlantic region, USA
Authors: Mirsky Steven B. , Ryan Matthew R. , Curran William S. , Teasdale John R. , Maul Jude , Spargo John T. , Moyer Jeff , Grantham Alison M. , Weber Donald , Way Thomas R. , Camargo Gustavo G.
Published: January 2012

Organic producers in the mid-Atlantic region of the USA are interested in reducing tillage, labor and time requirements for grain production. Cover crop-based, organic rotational no-till grain production is one approach to accomplish these goals. This approach is becoming more viable with advancements in a system for planting crops into cover crop residue flattened by a roller–crimper. However, inability to consistently control weeds, particularly perennial weeds, is a major constraint. Cover crop biomass can be increased by manipulating seeding rate, timing of planting and fertility to achieve levels (>8000 kg ha−1) necessary for suppressing summer annual weeds. However, while cover crops are multi-functional tools, when enhancing performance for a given function there are trade-off with other functions. While cover crop management is required for optimal system performance, integration into a crop rotation becomes a critical challenge to the overall success of the production system. Further, high levels of cover crop biomass can constrain crop establishment by reducing optimal seed placement, creating suitable habitat for seed- and seedling-feeding herbivores, and impeding placement of supplemental fertilizers. Multi-institutional and -disciplinary teams have been working in the mid-Atlantic region to address system constraints and management trade-off challenges. Here, we report on past and current research on cover crop-based organic rotational no-till grain production conducted in the mid-Atlantic region.
Characterization of frequency-selective surface spatial filters in a rectangular waveguide
Authors: Debarros Fabien , Lemaître-Auger Pierre , de Menezes Alysson Vasconcelos Gomes , Siragusa Romain , Vuong Tan-Phu , Tourtollet Guy Eymin Petot , Fontgalland Glauco
Published: January 2012

The possibility to characterize infinite and periodic frequency-selective surfaces (FSS) filters that have two orthogonal axes of symmetry inside a waveguide is reported. Thus, preliminary measurements can rapidly be obtained at low cost with few elementary cells instead of using a large FSS panel in free space. This is possible because of the equivalence that exists between the electromagnetic fields of two symmetric and oblique plane waves incident on and reflected from an infinite periodic surface and the incident/reflected fields that exist inside a single-mode rectangular waveguide containing a finite number of elementary cells. Comparisons of the measurements with some full-wave simulations for FSS belonging to the first three groups as they were defined by Munk confirm the good agreement between them. This is an interesting and simple assessment tool concerning the fabrication quality of FSS. The extension of this technique to non-symmetric FSS patterns is also discussed and supported by experimental and simulation results. The limitations of the technique are finally discussed.
The importance of secondary trauma exposure for post-disaster mental disorder
Authors: Kessler R. C. , McLaughlin K. A. , Koenen K. C. , Petukhova M. , Hill E. D. ,   The WHO World Mental Health Survey Consortium
Published: January 2012

Background.

Interventions to treat mental disorders after natural disasters are important both for humanitarian reasons and also for successful post-disaster physical reconstruction that depends on the psychological functioning of the affected population. A major difficulty in developing such interventions, however, is that large between-disaster variation exists in the prevalence of post-disaster mental disorders, making it difficult to estimate need for services in designing interventions without carrying out a post-disaster mental health needs assessment survey. One of the daunting methodological challenges in implementing such surveys is that secondary stressors unique to the disaster often need to be discovered to understand the magnitude, type, and population segments most affected by post-disaster mental disorders.

Methods.

This problem is examined in the current commentary by analyzing data from the WHO World Mental Health (WMH) Surveys. We analyze the extent to which people exposed to natural disasters throughout the world also experienced secondary stressors and the extent to which the mental disorders associated with disasters were more proximally due to these secondary stressors than to the disasters themselves.

Results.

Lifetime exposure to natural disasters was found to be high across countries (4.4–7.5%). 10.7–11.4% of those exposed to natural disasters reported the occurrence of other related stressors (e.g. death of a loved one and destruction of property). A monotonic relationship was found between the number of additional stressors and the subsequent onset of mental disorders

Conclusions.

These results document the importance of secondary stressors in accounting for the effects of natural disasters on mental disorders. Implications for intervention planning are discussed.
Person-Fit to the Five Factor Model of Personality
Authors: Allik Jüri , Realo Anu , Mõttus René , Borkenau Peter , Kuppens Peter , Hřebíčková Martina
Published: January 2012

The Five Factor Model (FFM), a valid model of interindividual differences in the personality of a group of people, reportedly does not always provide a good fit for the individuals of that group. In addition to intraindividual variation across a considerable period of time, meaningful intraindividual variation can be observed within a single test administration. Two person-fit indices showed that the FFM is an adequate model for 95% of the 1,765 target-judge pairs in four different countries (Belgium, the Czech Republic, Estonia, and Germany): the double-entry intraclass correlation (ICCDE), which indicated that the 30 NEO PI-R scores on scales measuring the same personality trait are more similar and certainly less different than scores measuring different traits, and the individual contribution to the extracted eigenvalues (Zeig). The individual response pattern to the personality questionnaire characterized by the ICCDE and Zeig strongly determined the percentage of explained variance for the group-level factor structure of interindividual differences and the mean self-observer profile agreement. We demonstrate that, if the percentage of variance explained by the first five principal components is high enough, the FFM also provides an adequate fit at the individual level for most people.
Intersubjective Culture
Authors: Fischer Ronald
Published: January 2012

Intersubjective consensus approaches to culture have emerged as a new paradigm for understanding and measuring culture. In this study, I briefly review contemporary definitions of culture in psychology and examine how an intersubjective norm approach may fit. Two central issues are (1) consensus about the norms and (2) the ability to discriminate between individuals from different cultural contexts based on their responses. A reanalysis of intersubjective norms (Fischer, 2006 ) demonstrates that consensus is low and relatively little variance is explained by cultural background. This challenges the theoretical nature of the construct as capturing culturally shared meaning systems.
The Impact of Visual Feedback Type on the Mastery of Visuo-Motor Transformations
Authors: Sülzenbrück Sandra
Published: January 2012

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.
Learning to Control Orientation and Force in a Hammering Task
Authors: Vernooij Carlijn A. , Mouton Leonora J. , Bongers Raoul M.
Published: January 2012

The ability to create stone tools is considered an important step in the emergence of human cognition. To further our understanding of these evolutionary processes we focused on the initial learning processes with which this percussive skill may be acquired. We studied a hammering task in which participants had to create a ground force vector by hitting a target on a force plate with a hammerstone. The produced ground force vector was presented as an arrow on a computer screen and had to end in a displayed target. The target could vary in its angle of azimuth and inclination. Over 5 days, three of the five participants adapted a wrist joint angle and two of these three participants adapted a shoulder joint angle that affected only angle of inclination of the ground force vector. Length and angle of azimuth of the ground force vector were not affected. In learning to control a hammering task, the first parameter to be manipulated seems to be the angle of inclination by adjusting the wrist and shoulder joint angles. This suggests that in the initial stages of learning a hammering task only one parameter is adapted.
Net ecosystem production in clear‐water and brown‐water lakes
Authors: Ask Jenny , Karlsson Jan , Jansson Mats
Published: January 2012

We studied 15 lakes in northern Sweden with respect to primary production and respiration in benthic and pelagic habitats. The lakes were characterized by different concentrations of colored dissolved organic carbon (DOC) of terrestrial origin, forming a gradient ranging from clear‐water to brown‐water lakes. Primary production decreased and respiration increased on a whole‐lake scale along the gradient of increasing DOC. Thus, the lakes became more net heterotrophic, i.e., had lower net ecosystem production (NEP = gross primary production – community respiration), with increasing terrestrial DOC and this change coincided with increasing partial pressure of carbon dioxide (pCO2) in the surface waters. The single most important process for the increasing net heterotrophy along the DOC gradient was pelagic respiration of terrestrial organic carbon. In spite of high metabolic activity in the benthic habitat, benthic primary production and benthic respiration decreased simultaneously with increasing DOC, showing that the benthic habitat was in metabolic balance throughout the gradient. Therefore, the net heterotrophic states of the lakes depended on the terrestrial DOC export to lakes and the concomitant respiration of terrestrial organic carbon in the pelagic habitat.
Interannual variability of Great Lakes ice cover and its relationship to NAO and ENSO
Authors: Bai Xuezhi , Wang Jia , Sellinger Cynthia , Clites Anne , Assel Raymond
Published: January 2012

The impacts of North Atlantic Oscillation (NAO) and El Niño–Southern Oscillation (ENSO) on Great Lakes ice cover were investigated using lake ice observations for winters 1963–2010 and National Centers for Environmental Prediction reanalysis data. It is found that both NAO and ENSO have impacts on Great Lakes ice cover. The Great Lakes tend to have lower (higher) ice cover during the positive (negative) NAO. El Niño events are often associated with lower ice cover. The influence of La Niña on Great Lakes ice cover is intensity‐dependent: strong (weak ) La Niña events are often associated with lower (higher) ice cover. The interference of impacts of ENSO and NAO complicates the relationship between ice cover and either of them. The nonlinear effects of ENSO on Great Lakes ice cover are important in addition to NAO effects. The correlation coefficient between the quadratic Nino3.4 index and ice cover (−0.48) becomes significant at the 99% confidence level. The nonlinear response of Great Lakes ice cover to ENSO is mainly due to the phase shift of the teleconnection patterns during the opposite phases of ENSO. Multiple‐variable nonlinear regression models were developed for ice coverage. Using the quadratic Nino3.4 index instead of the index itself can significantly improve the prediction of Great Lakes ice cover (the correlation between the modeled and observed increases from 0.35 to 0.51). Including the interactive term NAO·Nino3.42 further improves the prediction skill (the correlation increases from 0.51 to 0.59). The analysis is also applied to individual lakes. The model for Lake Michigan has the highest prediction skill, while Lake Erie has the smallest skill.
Shallow lithospheric contribution to mantle plumes revealed by integrating seismic and geochemical data
Authors: Konter Jasper G. , Becker Thorsten W.
Published: January 2012

Using an integrated geophysical and geological approach based on a comparative analysis of 27 different parameters, we investigate both the location and origin of the source material for hot spot volcanoes. We report a significant correlation between extreme geochemical compositions of lavas with both shallow seismic velocities and the depth extent to which a hot spot source can be traced with seismic tomography. These relationships provide the first integrated evidence for buoyantly rising plumes of mantle material (plume depth extent correlation), incorporating thermally eroded continental material in the shallow mantle (anti‐correlation with slow shallow seismic velocities). The extreme geochemical composition of the lavas is successfully modeled with this process, placing constraints on dynamical processes in the mantle and explaining the origin of a significantly debated mantle compositional end‐member (enriched mantle; EM1).
CALIOP observations of the transport of ash from the Eyjafjallajökull volcano in April 2010
Authors: Winker D. M. , Liu Z. , Omar A. , Tackett J. , Fairlie D.
Published: January 2012

The Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) is an elastic backscatter lidar carried on the CALIPSO satellite. CALIOP observations between 15 and 20 April 2010 of volcanic ash plumes following the eruption of the Icelandic Eyjafjallajökull volcano are reported here. While CALIOP has limited spatial coverage due to nadir‐only sampling, ash plumes were observed by CALIOP over a wide region ‐ from the North Atlantic Ocean to eastern Europe ‐ during both day and night. Due to its nadir‐only view, however, CALIOP did not sample the densest ash plumes which were observed by passive satellite sensors and ground‐based lidar. Lidar depolarization and spectral backscatter signatures are used to discriminate ash layers from clouds. Most ash was observed in thin layers of laminar appearance with thicknesses ranging from 0.4 km to a little more than 1 km and at relatively low altitudes, between 1 and 7 km. Most layers reported here produced strong lidar depolarization, indicating a predominance of ash over sulfate aerosol in the plumes. Estimates of lidar extinction‐to‐backscatter ratio allow the retrieval of profiles of ash optical properties. Layers were observed with mean optical extinction ranging from 0.03 km−1 to nearly 1 km−1. Combined with an estimate of mass extinction efficiency, mass concentration profiles can also be estimated. These observations of the three‐dimensional dispersion of the plume are complementary to observations from passive satellite instruments and ground‐based lidars, and can be useful for verification of dispersion models such as those used by the Volcanic Ash Advisory Centers.
A volatility basis set model for summertime secondary organic aerosols over the eastern United States in 2006
Authors: Ahmadov R. , McKeen S. A. , Robinson A. L. , Bahreini R. , Middlebrook A. M. , de Gouw J. A. , Meagher J. , Hsie E.‐Y. , Edgerton E. , Shaw S. , Trainer M.
Published: January 2012

A new secondary organic aerosol (SOA) parameterization based on the volatility basis set is implemented in a regional air quality model WRF‐CHEM. Full meteorological and chemistry simulations are carried out for the United States for August–September 2006. Predicted organic aerosol (OA) concentrations are compared against surface measurements made by several networks and aircraft data from the TexAQS‐2006 field campaign. Elemental carbon simulations are also evaluated in order to evaluate the model's ability to capture their emissions, transport, and removal. Certain measurement limitations, such as daily averaged OA concentrations, impose some difficulties on the model evaluation, and hourly averaged OA measurements provide more informative constraints compared to daily concentrations. The updated model demonstrates a significant improvement in simulating the OA concentrations compared to the standard WRF‐CHEM, which predicts very little SOA. The improvement in organic carbon (OC) predictions is noticeable in correlations and model bias. The correlations of OC exceed that of the persistence forecasts for hourly concentrations in the southeast United States during daytime. The updated traditional SOA yields still lead to an underestimation of observed OA, while addition of the multigenerational volatile organic compound (VOC) oxidation drastically improves model performance. However, several key uncertainties remain in SOA formation and loss mechanisms, which are characterized through several perturbation simulations. Dry deposition of VOC oxidation products is an important factor in the atmospheric SOA budget. The combination of the biogenic VOC emissions, updated SOA yields, and aging mechanism result in biogenic SOA being the dominant OA component for much of the nonurban United States.
Delayed formation of the equatorial ridge on Iapetus from a subsatellite created in a giant impact
Authors: Dombard Andrew J. , Cheng Andrew F. , McKinnon William B. , Kay Jonathan P.
Published: January 2012

The great equatorial ridge on Saturn's moon Iapetus is arguably the most perplexing landform in the solar system. The ridge is a mountain range up to 20 km tall and sitting on the equator of Iapetus, and explaining its creation is an unresolved challenge. Models of its formation must satisfy three critical observations: why the ridge (1) sits exactly on the equator, (2) is found only on the equator, and (3) is thus far found only on Iapetus. We argue that all previously proposed models fail to satisfy these observations, and we expand upon our previous proposal that the ridge ultimately formed from an ancient giant impact that produced a subsatellite around Iapetus. The orbit of this subsatellite would then decay, once Iapetus itself had despun due to tides raised by Saturn, until tidal forces from Iapetus tore the subsatellite apart. The resultant debris formed a transient ring around Iapetus, the material of which rained down on the surface to build the ridge. By sequestering the material in a subsatellite with a tidally evolving orbit, formation of the ridge is delayed, which increases the likelihood of preservation against the high‐impact flux early in the solar system's history and allows the ridge to form on thick, stiff lithosphere (heat flow likely <1 mW m−2) required to support this massive load without apparent flexure. This mechanism thus explains the three critical observations.
Assessing the nonconservative fluvial fluxes of dissolved organic carbon in North America
Authors: Lauerwald Ronny , Hartmann Jens , Ludwig Wolfgang , Moosdorf Nils
Published: January 2012

Fluvial transport of dissolved organic carbon (DOC) is an important link in the global carbon cycle. Previous studies largely increased our knowledge of fluvial exports of carbon to the marine system, but considerable uncertainty remains about in‐stream/in‐river losses of organic carbon. This study presents an empirical method to assess the nonconservative behavior of fluvial DOC at continental scale. An empirical DOC flux model was trained on two different subsets of training catchments, one with catchments smaller than 2,000 km2 (n = 246, avg. 494 km2) and one with catchments larger than 2,000 km2 (n = 207, avg. 26,525 km2). A variety of potential predictors and controlling factors of fluvial DOC fluxes is discussed. The predictors retained for the final DOC flux models are runoff, slope gradient, land cover, and areal proportions of wetlands. According to the spatially explicit extrapolation of the models, in North America south of 60°N, the total fluvial DOC flux from small catchments (25.8 Mt C a−1, std. err.: 12%) is higher than that from large catchments (19.9 Mt C a−1, std. err.: 10%), giving a total DOC loss of 5.9 Mt C a−1 (std. err.: 78%). As DOC losses in headwaters are not represented in this budget, the estimated DOC loss is rather a minimum value for the total DOC loss within the fluvial network.
Impact of aerosols on convective clouds and precipitation
Authors: Tao Wei‐Kuo , Chen Jen‐Ping , Li Zhanqing , Wang Chien , Zhang Chidong
Published: January 2012

Aerosols are a critical factor in the atmospheric hydrological cycle and radiation budget. As a major agent for clouds to form and a significant attenuator of solar radiation, aerosols affect climate in several ways. Current research suggests that aerosol effects on clouds could further extend to precipitation, both through the formation of cloud particles and by exerting persistent radiative forcing on the climate system that disturbs dynamics. However, the various mechanisms behind these effects, in particular, the ones connected to precipitation, are not yet well understood. The atmospheric and climate communities have long been working to gain a better grasp of these critical effects and hence to reduce the significant uncertainties in climate prediction resulting from such a lack of adequate knowledge. Here we review past efforts and summarize our current understanding of the effect of aerosols on convective precipitation processes from theoretical analysis of microphysics, observational evidence, and a range of numerical model simulations. In addition, the discrepancies between results simulated by models, as well as those between simulations and observations, are presented. Specifically, this paper addresses the following topics: (1) fundamental theories of aerosol effects on microphysics and precipitation processes, (2) observational evidence of the effect of aerosols on precipitation processes, (3) signatures of the aerosol impact on precipitation from large‐scale analyses, (4) results from cloud‐resolving model simulations, and (5) results from large‐scale numerical model simulations. Finally, several future research directions for gaining a better understanding of aerosol‐cloud‐precipitation interactions are suggested.