bluuebunny/crossref_metadata_2025 huggingface dataset:
Inverse odds ratio‐weighted estimation for causal mediation analysis
Authors: Tchetgen Tchetgen Eric J.
Published: June 2013

An important scientific goal of studies in the health and social sciences is increasingly to determine to what extent the total effect of a point exposure is mediated by an intermediate variable on the causal pathway between the exposure and the outcome. A causal framework has recently been proposed for mediation analysis, which gives rise to new definitions, formal identification results and novel estimators of direct and indirect effects. In the present paper, the author describes a new inverse odds ratio‐weighted approach to estimate so‐called natural direct and indirect effects. The approach, which uses as a weight the inverse of an estimate of the odds ratio function relating the exposure and the mediator, is universal in that it can be used to decompose total effects in a number of regression models commonly used in practice. Specifically, the approach may be used for effect decomposition in generalized linear models with a nonlinear link function, and in a number of other commonly used models such as the Cox proportional hazards regression for a survival outcome. The approach is simple and can be implemented in standard software provided a weight can be specified for each observation. An additional advantage of the method is that it easily incorporates multiple mediators of a categorical, discrete or continuous nature. Copyright © 2013 John Wiley & Sons, Ltd.
A new estimation with minimum trace of asymptotic covariance matrix for incomplete longitudinal data with a surrogate process
Authors: Chen Baojiang , Qin Jing
Published: June 2013

Missing data is a very common problem in medical and social studies, especially when data are collected longitudinally. It is a challenging problem to utilize observed data effectively. Many papers on missing data problems can be found in statistical literature. It is well known that the inverse weighted estimation is neither efficient nor robust. On the other hand, the doubly robust (DR) method can improve the efficiency and robustness. As is known, the DR estimation requires a missing data model (i.e., a model for the probability that data are observed) and a working regression model (i.e., a model for the outcome variable given covariates and surrogate variables). Because the DR estimating function has mean zero for any parameters in the working regression model when the missing data model is correctly specified, in this paper, we derive a formula for the estimator of the parameters of the working regression model that yields the optimally efficient estimator of the marginal mean model (the parameters of interest) when the missing data model is correctly specified. Furthermore, the proposed method also inherits the DR property. Simulation studies demonstrate the greater efficiency of the proposed method compared with the standard DR method. A longitudinal dementia data set is used for illustration. Copyright © 2013 John Wiley & Sons, Ltd.
Settling up in CEO compensation: The impact of divestiture intensity and contextual factors in refocusing firms
Authors: Pathak Seemantini , Hoskisson Robert E. , Johnson Richard A.
Published: June 2013

We examine the relationship between strategic change and CEO compensation by studying how a firm's refocusing program influences CEO compensation after completing the change. We contribute to the ‘settling up’ literature by arguing that strategic change is often uncertain for both the CEO and the board of directors responsible for executive compensation. As such the firm is likely to settle up with the CEO by paying for compensation risk and effort undertaken during refocusing after the extent and impact of strategic change are better known. We find that refocusing intensity is positively related to post‐refocusing CEO total compensation, suggesting that ‘settling up’ through post hoc compensation is an important factor in strategic change. We also find that prior firm performance, governance structure and industry dynamism are important moderators of this relationship. © 2013 John Wiley & Sons, Ltd.
Finite Element Analysis of High Pressure Torsion
Authors: Wei Peitang , Lu Cheng , Tieu Kiet , Deng Guanyu , Wang Haixia , Kong Ning
Published: June 2013

High pressure torsion (HPT) is an important process for producing ultrafine grained materials, and while numerous experimental investigations of HPT have been carried out, most concentrated on microstructure, texture, or the mechanical properties of the processed materials, while few work has been carried out by using FEM because of extreme mesh distortion during deformation. In this paper, a FEM model of HPT with a mapping solution method of Abaqus has been established and used to investigate the plastic deformation of HPT process, the stress and equivalent strain distribution and evolution along the radius and axial directions were presented, inhomogeneous deformation was observed along the radius and axial directions and a homogenous deformation could be anticipated if the strain applied reached a high enough level. The FEM results agreed quite well with the experimental results.
First‐trimester contingent screening for trisomy 21 by biomarkers and maternal blood cell‐free DNA testing
Authors: Nicolaides K. H. , Wright D. , Poon L. C. , Syngelaki A. , Gil M. M.
Published: June 2013

Objective

To define risk cut‐offs with corresponding detection rates (DR) and false‐positive rates (FPR) in screening for trisomy 21 using maternal age and combinations of first‐trimester biomarkers in order to determine which women should undergo contingent maternal blood cell‐free (cf) DNA testing.

Methods

From singleton pregnancies undergoing screening for aneuploidies at three UK hospitals between March 2006 and May 2012, we analyzed prospectively collected data on the following biomarkers: fetal nuchal translucency thickness (NT) and ductus venosus pulsatility index for veins (DV‐PIV) at 11 + 0 to 13 + 6 weeks' gestation and serum free β‐human chorionic gonadotropin (β‐hCG), pregnancy‐associated plasma protein‐A (PAPP‐A), placental growth factor (PlGF) and alpha‐fetoprotein (AFP) at 8 + 0 to 13 + 6 weeks. Estimates of risk cut‐offs, DRs and FPRs were derived for combinations of biomarkers and these were used to define the best strategy for contingent cfDNA testing.

Results

In contingent screening, detection of 98% of fetuses with trisomy 21 at an overall invasive testing rate < 0.5% can be potentially achieved by offering cfDNA testing to about 36%, 21% and 11% of cases identified by first‐line screening using the combined test alone, using the combined test with the addition of serum PlGF and AFP and using the combined test with the addition of PlGF, AFP and DV‐PIV, respectively.

Conclusions

Effective first‐trimester screening for trisomy 21, with DR of 98% and invasive testing rate < 0.5%, can be potentially achieved by contingent screening incorporating biomarkers and cfDNA testing. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Frontiers in free‐energy calculations of biological systems
Authors: Chipot Christophe
Published: June 2013

In a matter of three decades, free‐energy calculations have emerged as an indispensable tool to tackle deep biological questions that experiment alone has left unresolved. In spite of recent advances on the hardware front that have pushed back the limitations of brute‐force molecular dynamics simulations, opening the way to time and size scales hitherto never attained, they represent a cogent alternative to access with unparalleled accuracy the thermodynamics and possibly the kinetics that underlie the complex processes of the cell machinery. From a pragmatic perspective, the present review draws a picture of how the field has been shaped and invigorated by milestone developments, application, and sometimes rediscovery of foundational principles laid down years ago to reach new frontiers in the exploration of intricate biological phenomena. Through a series of illustrative examples, distinguishing between alchemical and geometrical transformations, it discusses how far free‐energy calculations have come, what are the current hurdles they have to overcome, and the challenges they are facing for tomorrow. WIREs Comput Mol Sci 2014, 4:71–89. doi: 10.1002/wcms.1157

This article is categorized under:

Molecular and Statistical Mechanics > Free Energy Methods
Estimation of plume distribution for carbon sequestration using parameter estimation with limited monitoring data
Authors: Espinet Antoine , Shoemaker Christine , Doughty Christine
Published: June 2013

This study develops and evaluates an integrated methodology including parameter zonation, efficient global optimization, and multiple aquifer realizations that gives a useful forecast of the pressure distribution and the CO2 plume migration through a heterogeneous storage formation, over time, using only a few monitoring locations in a feasibly short amount of computing time, while dealing with data error. Geological characteristics of the example application are similar to a CO2 sequestration pilot test conducted in a fluvial‐deltaic geological setting. In the example, the CO2 injection problem is simulated with the TOUGH2 code, a numerical simulator for multiphase (gas and aqueous), multicomponent flow and transport. The inverse problem is difficult because the GCS optimization estimation problem has multiple local minima and the simulation is computationally expensive. The efficient surrogate response surface global optimization algorithm “Stochastic RBF” (stochastic radial basis function) is used to calibrate the model parameters. Results are averaged over three saline aquifer realizations. In the third numerical experiment using only pressure data, the CO2 plume could be determined with an average correlation coefficient compared to the actual plume of up to R2 = 0.916 (for current plume at t = 1.5 years) and average R2 = 0.80 (for forecasted plume estimated at t = 7.5 years years, using only the first 1.5 years of monitoring data). Adding gas saturation data improved the 6 year forecast somewhat (increasing average R2 = 0.85) but it was not significantly helpful in estimating the current plume. Both our inverse methodology and findings can be broadly applicable to GCS in heterogeneous sedimentary formations.
Telegraphic double porosity models for head transient behavior in naturally fractured aquifers
Authors: Hernández D. , Núñez‐López M. , Velasco‐Hernández J. X.
Published: June 2013

We present a general phenomenological formalism for the modeling of hydraulic head behavior in naturally fractured aquifers. A nonlocal in time version of the double porosity model is developed for Euclidean and fractal reservoirs. In the fractal case, time nonlocality allows to find the geometric and topological factors responsible for subdiffusive behavior in such heterogeneous environments. Opposite to other fractal models presented in the literature, ours include dead‐ends‐backbone interactions instead of matrix‐fracture interactions with clear and well‐defined scaling exponents, thus giving a better characterization of the reservoir after such parameters are estimated. Applications to field tests are discussed. In particular, a distinctive short time head behavior during well tests is found.
Binary Decavanadate‐Betaine Composite Materials of Potential Anticarcinogenic Activity
Authors: Kioseoglou Efrosini , Gabriel Catherine , Petanidis Savvas , Psycharis Vassilis , Raptopoulou Catherine P. , Terzis Aris , Salifoglou Athanasios
Published: June 2013

Poised to investigate the association of vanadium with physiological substrates in materials capable of exerting anticancer biological activity, pH‐specific synthetic chemical reactivity between vanadium and triethyl ammonium acetate/trigonelline in aqueous and mixed organic‐aqueous media led to the isolation of three new binary composite materials, namely K2[(MeN(+)C5H4COOH)2][V10O28H2]·2H2O (1), [(H2N(+)Me2)4][V10O28H2][Me3N(+)CH2COO(–)]2 (2), and [(Me3N(+)CH2COOH)4][V10O28H2][Me3N(+)CH2COO(–)]2·2H2O (3). 1–3 were characterized by elemental analysis, FT‐IR and UV/Vis spectroscopy, Cyclic voltammetry, TGA‐DTG, and X‐ray crystallography. In all three compounds, the [V10O28H2]4– core unit is a common cluster assembly, with the vanadium in the +5 oxidation state. The counteracting cationic assembly in each composite material originates in the betaine starting reagent or the solvent out of which the materials crystallized. Biological activity studies of 1 and 3 in vitro in MCF‐7 breast epithelial and A549 lung adenocarcinoma cell cultures show that both materials inhibit the viability of both cell lines in a dose‐dependent fashion, in juxtaposition to the behavior of the betaine components present in these materials. Collectively, the herein studies a) reveal the uniquely defined synthetic methodologies and physicochemical properties of the variably assembled [V10O28H2]4– core units crystallized into the composite binary polyoxovanadate‐betaine lattice structures, b) unravel the distinct cytotoxicity profile of the composite materials toward MCF‐7 and A549 cells, and c) attest to their future potential as metallodrugs of pharmacological significance in anticancer activity.
Leaf carbon isotope ratio and water use efficiency of urban roadside trees in summer in Kyoto city
Authors: Kagotani Yuichi , Fujino Kousuke , Kazama Takahito , Hanba Yuko T.
Published: June 2013

The effect of summer climate on leaf carbon isotope composition (δ13C) of the major roadside tree species Prunus × yedoensis (P. yedoensis) was investigated in Kyoto city, Japan, to explore the implications for alterations in urban environments. Temperature and the vapor pressure deficit were higher at sites of higher traffic volumes, possibly affected by a heat island effect. The leaf δ13C of P. yedoensis trees was affected strongly by leaf carbon isotope discrimination (Δ), with much less effect of δ13C on atmospheric CO2. Leaf Δ values in the summer were smaller at sites of higher traffic volumes with high atmospheric temperatures, suggesting a higher long‐term water use efficiency (WUE) at these sites. Gas exchange measurements of P. yedoensis leaves indeed suggested a higher intrinsic WUE at sites of higher traffic volumes with high atmospheric temperatures. These results suggest that leaf Δ is related to the response of WUE to summer climates, and that leaf δ13C in urban areas is a useful tracer for understanding the influences of urban environments on plant photosynthetic processes.
The Effectiveness of Fish Oil Supplementation in Asthmatic Rats is Limited by an Inefficient Action on ASM Function
Authors: Miranda D. T. S. Z. , Zanatta A. L. , Dias B. C. L. , Fogaça R. T. H. , Maurer J. B. B. , Donatti L. , Calder P. C. , Nishiyama A.
Published: June 2013

Episodes of acute exacerbation are the major clinical feature of asthma and therefore represent an important focus for developing novel therapies for this disease. There are many reports that the n‐3 fatty acids found in fish oil exert anti‐inflammatory effects, but there are few studies of the action of fish oil on airway smooth muscle (ASM) function. In the present investigation, we evaluated the effect of fish oil supplementation on smooth muscle force of contraction in ovalbumin‐induced asthmatic Wistar rats, and its consequences on static lung compliance, mucus production, leukocyte chemotaxis and production of proinflammatory cytokines. Fish oil supplementation suppressed the infiltration of inflammatory cells into the lung in asthmatic animals (2.04 ± 0.19 × 106 cells vs. 3.33 ± 0.43 × 106 cells in the control asthmatic group; P < 0.05). Static lung compliance increased with fish oil supplementation in asthmatic rats (0.640 ± 0.053 mL/cm H2O vs. 0.399 ± 0.043 mL/cm H2O; P < 0.05). However, fish oil did not prevent asthma‐associated lung eosinophilia and did not affect the concentrations of tumor necrosis factor‐α and interleukin‐1β in lung tissue or the proportion of the airways obliterated with mucus. Fish oil had no effect on the force of contraction in asthmatic rats in response to acetylcholine (3.026 ± 0.274 mN vs. 2.813 ± 0.364 mN in the control asthmatic group). In conclusion, although fish oil exerts some benefits in this model of asthma, its effectiveness appears to be limited by an inefficient action on airway smooth muscle function.
Smooth approximation of bi-Lipschitz orientation-preserving homeomorphisms
Authors: Daneri Sara , Pratelli Aldo
Published: June 2013

We show that a planar bi-Lipschitz orientation-preserving homeomorphism can be approximated in the

W^{1,p}

norm, together with its inverse, with an orientation-preserving homeomorphism which is piecewise affine or smooth.
Late Wisconsinan glaciation and postglacial relative sea-level change on western Banks Island, Canadian Arctic Archipelago
Authors: Lakeman Thomas R. , England John H.
Published: June 2013

The study revises the maximum extent of the northwest Laurentide Ice Sheet (LIS) in the western Canadian Arctic Archipelago (CAA) during the last glaciation and documents subsequent ice sheet retreat and glacioisostatic adjustments across western Banks Island. New geomorphological mapping and maximum-limiting radiocarbon ages indicate that the northwest LIS inundated western Banks Island after ~ 3114C ka BP and reached a terminal ice margin west of the present coastline. The onset of deglaciation and the age of the marine limit (22–40 m asl) are unresolved. Ice sheet retreat across western Banks Island was characterized by the withdrawal of a thin, cold-based ice margin that reached the central interior of the island by ~ 14 cal ka BP. The elevation of the marine limit is greater than previously recognized and consistent with greater glacioisostatic crustal unloading by a more expansive LIS. These results complement emerging bathymetric observations from the Arctic Ocean, which indicate glacial erosion during the Last Glacial Maximum (LGM) to depths of up to 450 m.
CHARACTER CLUSTERS FOR LIE ALGEBRA MODULES OVER A FIELD OF NONZERO CHARACTERISTIC
Authors: BARNES DONALD W.
Published: June 2013

For a Lie algebra $L$ over an algebraically closed field $F$ of nonzero characteristic, every finite dimensional $L$-module can be decomposed into a direct sum of submodules such that all composition factors of a summand have the same character. Using the concept of a character cluster, this result is generalised to fields which are not algebraically closed. Also, it is shown that if the soluble Lie algebra $L$ is in the saturated formation $\mathfrak{F}$ and if $V, W$ are irreducible $L$-modules with the same cluster and the $p$-operation vanishes on the centre of the $p$-envelope used, then $V, W$ are either both $\mathfrak{F}$-central or both $\mathfrak{F}$-eccentric. Clusters are used to generalise the construction of induced modules.
ADDITION TO ‘AN UPPER BOUND FOR THE NUMBER OF ODD MULTIPERFECT NUMBERS’
Authors: YUAN PINGZHI , ZHANG ZHONGFENG
Published: June 2013

The main result in the earlier paper (by the first author) is improved as follows. The number of odd multiperfect numbers with at most $r$ distinct prime factors is bounded by ${4}^{{r}^{2} } / {2}^{r+ 2} (r- 1)!$.
Different emergence phenology of European grapevine moth (Lobesia botrana, Lepidoptera: Tortricidae) on six varieties of grapes
Authors: Thiéry D. , Monceau K. , Moreau J.
Published: June 2013

The phenology of insect emergence affects reproductive success and is especially critical in short-lived species. An increasing number of studies have documented the effects of thermal and other climatic variations and of unpredictable habitats on the timing of adult insect emergence within and between populations and years. Numerous interacting factors may affect the phenology of adult emergence. Host-plant quality and availability is a key factor that has been largely neglected in studies of the phenology of phytophagous insects. The purpose of this study was to determine the effect of host plant characteristics on the rate of larval growth and the pattern of emergence in a wild population ofLobesia botrana(European grapevine moth), a significant pest in European vineyards. The phenology of emergence differed significantly among the six tested varieties of grapes. The percentage of bunches harboring pupae was similar among the different grape varieties, and the total number of pupae collected was similar to the number of emerging adults per bunch. Among the six varieties of grapes, 0–25 pupae were produced on each bunch. Each of the grape varieties had a single wave of emergence, in which males emerged before females, but their emergence phenology differed significantly in Chardonnay, Chasselas, and Pinot grapes. Both genders had extended durations of emergence in Merlot grapes. Together, the present results show that the characteristics of the grape host plant affect the emergence phenology ofL. botrana.
Crustal xenoliths from Tallante (Betic Cordillera, Spain): insights into the crust–mantle boundary
Authors: BIANCHINI GIANLUCA , BRAGA ROBERTO , LANGONE ANTONIO
Published: June 2013

The volcano of Tallante (Pliocene) in the Betic Cordillera (Spain) exhumed a heterogeneous xenolith association, including ultramafic mantle rocks and diverse crustal lithologies. The latter include metagabbroids and felsic rocks characterized by quartz-rich parageneses containing spinel ± garnet ± sillimanite ± feldspars. Pressure–temperature estimates for felsic xenoliths overlap (at 0.7–0.8 GPa) those recorded by the mantle-derived peridotite xenoliths. Therefore, we propose that an intimate association of interlayered crust and mantle lithologies characterizes the crust–mantle boundary in this area. This scenario conforms to evidence provided by the neighbouring massifs of Ronda and Beni Bousera (and by other peri-Mediterranean deep crust/mantle sections) where exhumation of fossil crust–mantle boundary reveals that this boundary is not sharp. The results are discussed on the basis of recent geophysical and petrological studies emphasizing that in non-cratonic regions the crust–mantle boundary is often characterized by a gradational nature showing inter-fingering of heterogeneous lithologies. Silica-rich melts formed within the crustal domains intruded the surrounding mantle and induced metasomatism. The resulting hybrid crust–mantle domains thus provide suitable sources for exotic magma types such as the Mediterranean lamproites.
Going Dutch in the Modern Age: Abraham Kuyper's Struggle for a Free Church in the Nineteenth-Century Netherlands
Authors: WOOD JOHN HALSEY
Published: June 2013

The nineteenth century witnessed a transition from the ancien régime to the ‘age of mobilisation’, says Charles Taylor, from an organically and hierarchically connected society to a fragmented society based on mass participation, charismatic leaders and organisational tactics. Amid this upheaval the Netherlands Reformed Church faced an unprecedented crisis as it lost its taken-for-granted social status. This essay examines the new legitimation that Abraham Kuyper offered the Church through his Free Church theology, and how various other aspects of his theology, including his baptismal and public theology, developed in conjunction with his ecclesiology. Kuyper's ecclesiology thus offers a case study of problems that ecclesiology in general faced due to the social and cultural shifts of the nineteenth century.
‘Lausanne 1974’: The Challenge from the Majority World to Northern-Hemisphere Evangelicalism
Authors: STANLEY BRIAN
Published: June 2013

The International Congress on World Evangelization held in Lausanne, Switzerland, in July 1974 was a seminal event in the history of Evangelicalism. This article considers the significance of the congress as an arena for the emergence of challenges from Latin America and Africa to the social and political conservatism that characterised much of the Evangelical movement in the northern hemisphere. These challenges demanded that Christian mission should be defined as a broader process than evangelism alone, and made their mark on the ‘Lausanne Covenant’, a document adopted by the congress which has had normative status among Evangelicals ever since.
Gargano Comes to Rome: Castel Sant'Angelo's Historical Origins
Authors: SHWARTZ LOUIS
Published: June 2013

This article explores the early medieval transformation of a pagan Roman monument, Hadrian's tomb, into a Christian fortress consecrated to St Michael. Ado of Vienne's claim that Boniface IV (608–15) dedicated an elevated chapel to the archangel atop the ‘moles Hadriani’ is challenged and reexamined. The many similarities between Michael's shrine on Monte Gargano and this Roman chapel instead indicate that the angelic devotion spread from Gargano to Rome, sometime in the early eighth century, and that the Lombards were the likely transmitters.
Structural modelling studies and immunoprophylactic potential ofBrugia malayiDEAD Box RNA helicase
Authors: SINGH MEGHNA , SHRIVASTAVA NIDHI , SAQIB UZMA , SIDDIQI MOHAMMAD IMRAN , MISRA-BHATTACHARYA SHAILJA
Published: June 2013

DEAD Box RNA helicases are essential enzymes that are involved in RNA metabolic processes such as transcription, pre-mRNA splicing, translation initiation and RNA decay. We have previously over-expressed and biochemically characterized an immunodominant cDNA clone encoding DEAD box RNA helicase (BmL3-Helicase) isolated by immunoscreening of the larval stage cDNA library ofBrugia malayi.In the current study, the 3D structure was determined and the immunoprophylactic efficacy of BmL3-Helicase was investigated by immunizingMastomys couchawith the recombinant protein and subsequently challenging withB. malayiinfective larvae. The immunization had an adverse outcome on the establishment of challenged larvae resulting in a 67·4% reduction in adult parasite recovery, a 86·7% decrease in the microfilarial density and profound sterility of the recovered female worms. The immune response thus generated was investigated by measuring the levels of specific antibodies including IgG subclasses, reactive oxygen species and cytokines.
In vivo efficacy of PF1022A and nicotinic acetylcholine receptor agonists alone and in combination against Nippostrongylus brasiliensis
Authors: KULKE DANIEL , KRÜCKEN JÜRGEN , HARDER ACHIM , KREBBER RALPH , FRAATZ KRISTINE , MEHLHORN HEINZ , VON SAMSON-HIMMELSTJERNA GEORG
Published: June 2013

The cyclooctadepsipeptide PF1022A and the aminophenylamidines amidantel, deacylated amidantel (dAMD) and tribendimidine were tested as examples for drug classes potentially interesting for development as anthelmintics against human helminthiases. These compounds and levamisole were tested alone and in combination to determine their efficacy against the rat hookworm Nippostrongylus brasiliensis. After three oral treatments, intestinal worms were counted. Drug effects on parasite morphology were studied using scanning electron microscopy (SEM). Plasma pharmacokinetics were determined for tribendimidine and dAMD. All drugs reduced worm burden in a dose-dependent manner, however amidantel was significantly less active than the other aminophenylamidines. Combinations of tribendimidine and dAMD with levamisole or PF1022A at suboptimal doses revealed additive effects. While PF1022A caused virtually no changes in morphology, levamisole, dAMD and tribendimidine caused severe contraction, particularly in the hind body region. Worms exposed to combinations of PF1022A and aminophenylamidines were indistinguishable from worms exposed only to aminophenylamidines. After oral treatment with tribendimidine, only the active metabolite dAMD was detectable in plasma and concentrations were not significantly different for oral treatment with dAMD. The results support further evaluation of cyclooctadepsipeptides alone and in combination with cholinergic drugs to improve efficacy. Combining these with registered drugs may help to prevent development of resistance.
Artificial moment method using attractive points for the local path planning of a single robot in complicated dynamic environments
Authors: Xu Wang-bao , Zhao Jie , Chen Xue-bo , Zhang Ying
Published: June 2013

A novel path planner is presented for the local path planning of a single robot (represented withR) in a complicated dynamic environment. Here a series ofattractive pointsare computed based onattractive segmentsfor guidingRto move along a shorter path. Each attractive segment is obtained by using the full environmental knowledge and will be used for several sampling times in general. A motion controller, which is designed based on artificial moments and a robot model that has a principal motion direction line(PMDline), makesRmove closely to attractive points while away from obstacles. Attractive and repulsive moments are designed, which only makeR's PMDline face toward attractive points and opposite to obstacles in general, as in most cases,Rwill move along its PMDline with its full speed. Because of the guidance of attractive points andR's full-speed motion, the global convergence is guaranteed. Simulations indicate that the proposed path planner meets the requirements of real-time property while can optimizeR's traveling path.
Design and operation of a 2-DOF leg–wheel hybrid robot
Authors: Ottaviano Erika , Rea Pierluigi
Published: June 2013

In this paper the design and operation for a 2-Degree-of-Freedom, leg–wheel hybrid mobile robot are presented. A prototype of a low-cost and easy-to-use system, which is capable of straight walking and steering with two actuators only, has been designed and built. Simulation and experimental tests have been carried out to verify the engineering feasibility and operation of the proposed solution. The designed robot can be used for applications such as surveillance and inspection of disaster sites.
Spinach seed quality: potential for combining seed size grading and chlorophyll fluorescence sorting
Authors: Deleuran Lise C. , Olesen Merete H. , Boelt Birte
Published: June 2013

Spinach (Spinacia oleracea L.) seed quality is important for subsequent establishment of baby leaf and other spinach products. The indeterminate flowering pattern in spinach produces seeds of different sizes, and consequently a non-uniform seed lot. Sorting seeds based on novel sorting methods might therefore improve the establishment of spinach for producers. Spinach seeds were harvested at five different times (H1, H2, H3, H4 and H5) starting 3 weeks before estimated optimum harvest time. The harvested seeds were sorted according to chlorophyll fluorescence (CF) and seed size. Two harvest times 6 d apart were selected for further studies of seed development and germination counts. Analysis of mean germination time (MGT) of four germination counts (3, 7, 14 and 21 d) showed that smaller seed sizes ( < 3.25 mm) have lower MGT than seeds of larger sizes (>3.25 mm). A larger proportion of 2.5–3.25 mm size seeds had germinated on day 3 than both their larger and smaller counterparts at the later time of harvest (H4). Seeds with a diameter below 2.5 mm displayed the lowest MGT. Commercially, the use of chlorophyll fluorescence (CF)-sorted seeds, in combination with seed size sorting, may provide a useful tool for enhancing seed quality. Here our results demonstrate that a greater number of seeds with a low CF level had germinated on day 3 compared to the seeds with high CF levels. It is of relevance to develop a technology that could identify seeds that are sufficiently developed to germinate and successfully establish in the field regardless of seed size.
Is there an association between cortical thickness, age of onset, and duration of illness in schizophrenia?
Authors: Assunção Leme Idaiane Batista , Gadelha Ary , Sato João Ricardo , Kiyomi Ota Vanessa , de Jesus Mari Jair , Melaragno Maria Isabel , de Arruda Cardoso Smith Marilia , Nogueira Belangero Sintia Iole , Bressan Rodrigo Affonseca , Jackowski Andrea Parolin
Published: June 2013

Objective

Several studies have shown cortical volume loss in frontotemporal regions in schizophrenia patients, and it is known that these reductions may be associated with disease symptoms and cognitive deficits. The aim of this study was to investigate possible cortical thickness correlations in frontotemporal regions in relation to age at onset and duration of illness.

Methods

One hundred forty-eight schizophrenia patients (97 males; age and SD 36.30 ± 10.06) and 87 (57 males; age and SD 36.48 ± 10.10) age-matched healthy subjects underwent a brain MRI scan. Cortical segmentation and surface statistical analysis were performed using the FreeSurfer software package. Results were corrected for multiple comparisons using the Monte Carlo method considering a cluster-corrected Type I Error of 5%.

Results

Compared to controls, schizophrenia patients presented significant cortical thinning in the frontotemporal, parietal, and occipital cortices. No correlation between prefrontal cortex thickness and duration of illness in patients with schizophrenia or between frontotemporal cortical thickness and age at onset was found. However, a significant interaction between age and diagnosis was observed on frontal cortical thickness with patients presenting a thinner cortex than expected for age.

Conclusion

Although there was no correlation between age of onset and duration of illness with brain volume, our findings suggest that there is an accelerated cortical loss in schizophrenia, thus reinforcing the progressive processes of the disease.
HOW DO INTERNATIONAL STOCK MARKETS RESPOND TO OIL DEMAND AND SUPPLY SHOCKS?
Authors: Güntner Jochen H. F.
Published: June 2013

Building on Kilian and Park's (2009) structural VAR analysis of the effects of oil demand and supply shocks on the U.S. stock market, this paper focuses on the differences and commonalities of stock price responses in oil exporting and importing economies in 1974–2011. Structural oil price shocks add to our understanding of the 2008 stock market crash. I find that unexpected reductions in world oil supply do not affect stock returns in any of six OECD countries. Although an increase in global aggregate demand consistently raises oil prices and cumulative real stock returns, the effect is more persistent for oil exporters. Other, e.g., precautionary oil demand shocks have a detrimental impact on stock markets in oil-importing countries, a statistically insignificant effect for Canada, and a significantly positive effect for Norway. Oil price shocks account for a larger share of the variation in aggregate international stock returns than in national stock returns.
Adsorption Kinetics of DPPG Liposome Layers: A Quantitative Analysis of Surface Roughness
Authors: Duarte Andreia A. , Filipe Sérgio L. , Abegão Luís M.G. , Gomes Paulo J. , Ribeiro Paulo A. , Raposo Maria
Published: June 2013

Roughness of a positively charged poly(allylamine hydrochloride) (PAH) polyelectrolyte surface was shown to strongly influence the adsorption of 1.2-dipalmitoyl-sn-3-glycero-[phosphorrac-(1-glycerol)] (DPPG) liposomes on it. The adsorption kinetic curves of DPPG liposomes onto a low-roughness PAH layer reveal an adsorbed amount of 5 mg/m2, pointing to liposome rupture, whereas a high-roughness surface leads to adsorbed amounts of 51 mg/m2, signifying adsorption of intact liposomes. The adsorption kinetic parameters calculated from adsorption kinetic curves allow us to conclude that the adsorption process is due to electrostatic interactions and also depends on processes such as diffusion and reorganization of lipids on the surface. Analysis of the roughness kinetics enabled us to calculate a growth exponent of 0.19 ± 0.07 and a roughness exponent of around 0.84, revealing that DPPG liposomes adsorbed onto rough surfaces follow the Villain self-affine model. By relating self-affine surfaces with hydrophobicity, the liposome integrity was explained by the reduction in the number of water molecules on the PAH surface, contributing to counterion anchorage near PAH ionic groups, reducing the liposome/PAH layer electrostatic forces and, consequently, avoiding liposome rupture.
FELL BUNDLES AND IMPRIMITIVITY THEOREMS: MANSFIELD’S AND FELL’S THEOREMS
Authors: KALISZEWSKI S. , MUHLY PAUL S. , QUIGG JOHN , WILLIAMS DANA P.
Published: June 2013

In the third and latest paper in this series, we recover the imprimitivity theorems of Mansfield and Fell using our technique of Fell bundles over groupoids. Also, we apply the Rieffel surjection of the first paper in the series to relate our version of Mansfield’s theorem to that of an Huef and Raeburn, and to give an automatic amenability result for certain transformation Fell bundles.
Unexceptional exceptionalism: the origins of American football in a transnational context
Authors: Collins Tony
Published: June 2013

This article explores the origins and early history of American football in relation to the development of rugby and similar codes in the English-speaking world of the last third of the nineteenth century. It suggests that the traditional narrative description of the emergence of the American game – which is ascribed in large part to the individual initiative of Walter Camp – fails to situate the sport in the context of the wider, transnational dynamics of the development of the various handling codes of football. In particular, it contends that the common assumption that the gridiron game's early development was a sporting expression of American exceptionalism is mistaken and that it only acquired its distinctive national character in the early twentieth century.
Cricket and globalization: global processes and the imperial game
Authors: Mustafa Fahad
Published: June 2013

This article seeks to reposition sport as a subject of analysis in ‘global historical’ processes. It examines the diffusion of cricket in the British empire, its appropriation by the colonies, and the subsequent commercialization of the sport. It asks the question: how did an elite English sport come to be one controlled by a former colony – India? With this as the substantive question, it seeks to develop theoretical insights about the nature of global processes and cultural transfers in the twentieth century. By way of conclusion, it asserts that, as a result of these global processes, there was a tangible shift in the ‘cultural economy’ of sports from the developed nations of the West to the developing nations.
Cognitive behaviour therapy using the Clark & Wells model: a case study of a Japanese social anxiety disorder patient
Authors: Yoshinaga Naoki , Kobori Osamu , Iyo Masaomi , Shimizu Eiji
Published: June 2013

Cognitive behaviour therapy (CBT) is widely regarded as an effective treatment for social anxiety disorder (SAD) in Europe and North America. The theoretical orientations underlying CBT models and treatment interventions developed in Western cultures were typically constrained by Western conceptualizations of SAD. This case study reports on the use of CBT for Japanese SAD, demonstrating the successful implementation of cognitive techniques grounded in the Clark & Wells model. The patient was a Japanese female with excessively high standards for workplace social performance. Therapy mainly comprised case formulation, behavioural experiments, and opinion surveying based on the Clark & Wells model. These techniques allowed the patient to reduce the strength of maladaptive cognitions and lower her excessively high standards for social performance. CBT treatment using the Clark & Wells model was effective and suitable for Japanese SAD, at least in the present case. We also discuss the cross-cultural differences of SAD and adaptation of CBT.
Committed changes in tropical tree cover under the projected 21st century climate change
Authors: Zeng Zhenzhong , Piao Shilong , Chen Anping , Lin Xin , Nan Huijuan , Li Junsheng , Ciais Philippe
Published: June 2013

Warming and drought pose a serious threat to tropical forest. Yet the extent of this threat is uncertain, given the lack of methods to evaluate the forest tree cover changes under future climate predicted by complex dynamic vegetation models. Here we develop an empirical approach based on the observed climate space of tropical trees to estimate the maximum potential tropical tree cover (MPTC) in equilibrium with a given climate. We show that compared to present-day (2000–2009) conditions, MPTC will be reduced by 1 to 15% in the tropical band under equilibrium future (2090–2099) climate conditions predicted by 19 IPCC climate models. Tropical forests are found to regress or disappear mainly in the current transition zones between forest and savanna ecosystems. This climate pressure on tropical forests, added to human-caused land use pressure, poses a grand challenge to the sustainability of the world's largest biomass carbon pool.
Spinocerebellar ataxia-13 Kv3.3 potassium channels: arginine-to-histidine mutations affect both functional and protein expression on the cell surface
Authors: Zhao Jian , Zhu Jing , Thornhill William B.
Published: June 2013

The voltage-gated potassium channel Kv3.3 is the causative gene of SCA13 (spinocerebellar ataxia type 13), an autosomal dominant neurological disorder. The four dominant mutations identified to date cause Kv3.3 channels to be non-functional or have altered gating properties in Xenopus oocytes. In the present paper, we report that SCA13 mutations affect functional as well as protein expression of Kv3.3 channels in a mammalian cell line. The reduced protein level of SCA13 mutants is caused by a shorter protein half-life, and blocking the ubiquitin–proteasome pathway increases the total protein of SCA13 mutants more than wild-type. SCA13 mutated amino acids are highly conserved, and the side chains of these residues play a critical role in the stable expression of Kv3.3 proteins. In addition, we show that mutant Kv3.3 protein levels could be partially rescued by treatment with the chemical chaperone TMAO (trimethylamine N-oxide) and to a lesser extent with co-expression of Kv3.1b. Thus our results suggest that amino acid side chains of SCA13 positions affect the protein half-life and/or function of Kv3.3, and the adverse effect on protein expression cannot be fully rescued.
A highly efficient peptide substrate for EGFR activates the kinase by inducing aggregation
Authors: Engel Kate , Sasaki Tomoaki , Wang Qi , Kuriyan John
Published: June 2013

Formation of an asymmetric dimer by the EGFR (epidermal growth factor receptor) kinase domains results in allosteric activation. Since this dimer does not readily form in solution, the EGFR kinase domain phosphorylates most peptide substrates with a relatively low catalytic efficiency. Peptide C is a synthetic peptide substrate of EGFR developed by others that is phosphorylated with a significantly higher catalytic efficiency, and we sought to understand the basis for this. Peptide C was found to increase EGFR kinase activity by promoting formation of the EGFR kinase domain asymmetric dimer. Activation of the kinase domain by Peptide C also enhances phosphorylation of other substrates. Aggregation of the EGFR kinase domain by Peptide C probably underlies activation, and Peptide C precipitates several other proteins. Peptide C was found to form fibrils independent of the presence of EGFR, and these fibrils may facilitate aggregation and activation of the kinase domain. These results establish that a peptide substrate of EGFR may increase catalytic activity by promoting kinase domain dimerization by an aggregation-mediated mechanism.
Bit‐error‐rate performance improvement of mobile dual‐hop relaying systems using directional antennas
Authors: Ahmed Hassan A. , Sulyman Ahmed Iyanda , Hassanein Hossam S.
Published: June 2013

The bit‐error‐rate (BER) performance of orthogonal frequency division multiplexing (OFDM) systems in mobile multi‐hop relaying (MMR) system is severely degraded by the effect of Doppler shift and the severity of this degradation increases with the number of hops traversed by the OFDM signal. In this study, the authors propose a method to mitigate the effect of Doppler shift in MMR system (such as the IEEE 802.16j system) using directional antennas. It is shown that the effect of the resulting inter‐carrier interference (ICI) because of the phase noise generated by the Doppler shift over multi‐hop relaying channels, can be reduced by employing directional antennas at both the mobile and relay stations. Consequently, the BER performance of MMR system is significantly enhanced. Analysis and simulation results show that the BER enhancements using the proposed approach are strongly related to the orientation and beamwidth of the directional antenna employed. As the antenna beamwidth is reduced, the BER enhancement increases for both the perpendicular and parallel antenna orientations, and comparing these two orientations, the parallel orientation case provides slightly better BER enhancements.
Microfabrication of cooling arm for fusion energy source application
Authors: Jiang Shui‐Dong , Liu Jing‐Quan , Yang Bin , Zhu Hong‐Ying , Yang Chun‐Sheng
Published: June 2013

The cooling arm plays an important role in the production process of fusion energy. The structure is designed with 16 fingers and is simulated by the finite‐element method. The (111) crystal orientation silicon is deployed to fabricate a cooling arm, because of its isotropic Young's modulus. It can make the fingers generate a uniform force. The silicon also has a large thermal conductivity of 2400 W/mK measured by a Gifford‐McMahon cooler, which contributes to heat transfer. The cooling arm is fabricated by the microfabrication process, and it has a high sidewall vertical degree of 90 ± 0.5° measured by scanning electron microscopy. The mechanical testing result shows that the maximum stress of the clamping arm was 0.209 GPa when it was in gripping state. The maximum stress is far smaller than the yield strength of 7 GPa of silicon material.
H2CN+ and H2CNH+: New insight into the structure and dynamics from mass-selected threshold photoelectron spectra
Authors: Holzmeier Fabian , Lang Melanie , Hader Kilian , Hemberger Patrick , Fischer Ingo
Published: June 2013

In this paper, we reinvestigate the photoionization of nitrogen containing reactive intermediates of the composition H2CN and H2CNH, molecules of importance in astrochemistry and biofuel combustion. In particular, H2CN is also of considerable interest to theory, because of its complicated potential energy surface. The species were generated by flash pyrolysis, ionized with vacuum ultraviolet synchrotron radiation, and studied by mass-selected threshold photoelectron (TPE) spectroscopy. In the mass-selected TPE-spectrum of m/z = 28, contributions of all four isomers of H2CN were identified. The excitation energy to the triplet cation of the methylene amidogen radical H2CN was determined to be 12.32 eV. Considerable activity in the C–N mode of the cation is visible. Furthermore, we derived values for excitation into the triplet cations of 11.72 eV for cis-HCNH, 12.65 eV for trans-HCNH, and 11.21 eV for H2NC. The latter values are probably accurate to within one vibrational quantum. The spectrum features an additional peak at 10.43 eV that corresponds to excitation into the C2v-symmetric H2CN+. As this structure constitutes a saddle point, the peak is assigned to an activated complex on the singlet potential energy surface of the cation, corresponding to a hydrogen atom migration. For methanimine, H2CNH, the adiabatic ionization energy IEad was determined to be 9.99 eV and the vibrational structure of the spectrum was analyzed in detail. The uncertainty of earlier values that simply assigned the signal onset to the IEad is thus considerably reduced. The spectrum is dominated by the H–N–C bending mode ν1+ and the rocking mode ν3+. All experimental data were supported by calculations and Franck-Condon simulations.