bluuebunny/crossref_metadata_2025 huggingface dataset:
RACK1 research – ships passing in the night?
Authors: Gibson Toby J.
Published: May 2012

It should not be surprising that a protein with a name like RACK1 – short for receptor for activated C kinase 1 – is found in a variety of signaling complexes. Its alternative name, the splendidly unmemorable GNB2L1 – short for guanine nucleotide‐binding protein subunit beta‐2‐like 1 – should reinforce this link to signaling complexes. There are currently over 400 publications listed in PubMed mentioning RACK1/GNB2L1 in the abstract, so it is certainly an actively studied protein with much involvement in different aspects of cell regulation being reported. RACK1 binds to the 40S ribosomal subunit, suggesting it links cell regulation and translation. It is also a target of intracellular parasites. And yet does this protein have the profile that it should? And why are there two kinds of RACK1 researcher who do not seem to communicate well?
Thermal Instability of Compressible Micropolar Fluid in the Presence of Suspended Particles
Authors: Rani N. , Tomar S. K.
Published: May 2012

A problem of thermal instability of a compressible micropolar fluid layer heated from below in the presence of suspended particles has been investigated. Dispersion relation is derived and Rayleigh number curve is then plotted against the wavenumber at different values of compressibility parameter for a model example. Compressibility is found to be responsible to destabilize the system in the presence and absence of suspended particles for both stationary and over stationary convection.
Dynamic Stress Concentration of a Cylindrical Cavity in Half-Plane Excited by Standing Goodier-Bishop Stress Wave
Authors: Liao W.-I , Teng T.-J.
Published: May 2012

Based on expansion technique, the dynamic stress concentration of a cylindrical cavity buried in an elastic half-plane is studied in the paper. The cavity and the half-plane are excited by a harmonic standing Goodier-Bishop stress wave which, as a result of taking the normalized frequency tends to zero, is equivalent to a simple uniform static tension parallel to the ground surface. In the formulation, the scattered waves are represented by a series expansion, and their associated modal fields of the expansion satisfy the boundary conditions on the ground surface as well as the radiation condition at infinity. As a consequence, the scattering problem is reduced to the determination of the expansion coefficients by matching the boundary conditions on the cavity. The numerical technique based on the steepest descent method is used to calculate the integral representation of potential functions in wave-number domain. Numerical results for the dynamic hoop stresses around the wall of the cavity and the dynamic stress concentration factors with various buried depth and excitation frequencies are presented.
Homogenization Theory Applied to Unsaturated Solid-Liquid Mixture
Authors: Liu K.-F. , Wu Y.-H. , Hsu Y.-C.
Published: May 2012

In this study, we present theoretical derivation of seepage flow in unsaturated and static soil using Homogenization theory. The derivation started in the microscopic scale in the soil. The representative elementary volume (REV) in the soil is set to be one order larger than the scale of characteristic length of pore. Solids in the REV are assumed to be rigid and cohesionless. The liquid velocity in the pore is slow. By no-slip boundary condition on the solid boundary in REV, we could obtain the microscopic flow conditions. Using spatial ensemble average under the microscopic scale, we obtain the relation between water content, pressure head and velocities in macroscopic scale. This macroscopic averaged equation is validated to be equal to Richards' equation.
Creep Buckling and Post-Buckling Analyses of a Viscoelastic FGM Cylindrical Shell with Initial Deflection Subjected to a Uniform In-Plane Load
Authors: Dai H.-L. , Zheng H.-Y.
Published: May 2012

In this paper, based on the viscoelastic theory, the creep buckling and post-buckling behaviors of a viscoelastic functionally graded material (FGM) cylindrical shell with initial deflection subjected to a uniform in-plane load are investigated. The material properties of the viscoelastic FGM cylindrical shell are assumed to vary through the structural thickness according to a power law distribution of the volume fraction of constituent materials and Poisson's ratio is assumed as a constant. Considering the transverse shear deformation and geometric nonlinearity, the constitutive relation of the viscoelastic FGM cylindrical shell is established. By means of the Newton-Newmark method and the Boltzmann superposition principle, the problem for the creep buckling and post-buckling of the FGM cylindrical shell is solved. The numerical results reveal that the transverse shear deformation, volume fraction and geometric parameters have significant effects on the creep buckling and post-buckling of the viscoelastic FGM cylindrical shell.
Personality disorders, common mental disorders and receipt of disability benefits: evidence from the British National Survey of Psychiatric Morbidity
Authors: Knudsen A. K. , Skogen J. C. , Harvey S. B. , Stewart R. , Hotopf M. , Moran P.
Published: May 2012

Background

Common mental disorders (CMDs) are associated with occupational impairment and the receipt of disability benefits (DBs). Little is known about the relationship between personality disorders (PDs) and work disability, and whether the association between CMDs and work disability is affected by the presence of co-morbid PDs. The aim of this study was to examine the association between DB and individual categories of PDs, with special attention to the effect of co-morbid CMDs on this association.

Method

The association between DB and PD was examined using data from the 2000 British National Survey of Psychiatric Morbidity. Probable PD caseness was identified using the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II) screening questionnaire. The impact of CMDs, assessed with the revised version of the Clinical Interview Schedule (CIS-R), was examined as a covariate and in a stratified analysis of co-morbidity. Other covariates included sociodemographic factors, long-standing illnesses and substance use.

Results

Probable PD was associated with DB, with the strongest associations found for borderline, dependent and schizotypal PD. Antisocial PD was not associated with DB. The relationship between PD and DB was strongly modified by CMD, reducing the association from an odds ratio (OR) of 2.84 to 1.34 [95% confidence interval (CI) 1.00–1.79)]. In the stratified analysis, co-morbid PD and CMD showed a stronger association with DB than PD without CMD but, when fully adjusted, this effect was not significantly different from the association between CMD without PD.

Conclusions

Individuals screening positive for PD are more likely to experience severe occupational outcomes, especially in the presence of co-morbid CMD.
Thurston equivalence for rational maps with clusters
Authors: SHARLAND THOMAS
Published: May 2012

We investigate rational maps with period-one and period-two cluster cycles. Given the definition of a cluster, we show that, in the case where the degree is$d$and the cluster is fixed, the Thurston class of a rational map is fixed by the combinatorial rotation number$\rho $and the critical displacement$\delta $of the cluster cycle. The same result will also be proved in the case where the rational map is quadratic and has a period-two cluster cycle, and we will also show that the statement is no longer true in the higher-degree case.
“To Get Rich Is Not Only Glorious”: Economic Reform and the New Entrepreneurial Party Secretaries
Authors: Xiaojun Yan
Published: May 2012

This article examines the profound transformation market reforms have brought to the leadership of the Chinese Communist Party's (CCP) rural grassroots organizations. Focusing on the political rise of private entrepreneurs and other economically successful individuals who recently obtained village Party secretary appointments in a north China county, the article explores their differing promotion channels, power bases, political resources and motivations to take up the CCP's grassroots leadership position. It demonstrates that the variety among the new entrepreneurial Party secretaries – from large factory owners to de facto farm managers – shaped the network resource, factional affiliation and socio-political capital they rely upon to exercise their newly attained power. It also shows the crucial role played by community-based endogenous forces in transmitting the power of economic liberalization into dynamics for the reshuffling of the Communist Party leadership at the grassroots level.
Frames of reference and their neural correlates within navigation in a 3D environment
Authors: VAVREČKA MICHAL , GERLA VÁCLAV , LHOTSKÁ LENKA , BRUNOVSKÝ MARTIN
Published: May 2012

The goal of this study was an administration of the navigation task in a three-dimensional virtual environment to localize the electroencephalogram (EEG) features responsible for egocentric and allocentric reference frame processing in a horizontal and also in a vertical plane. We recorded the EEG signal of a traverse through a virtual tunnel to search for the best signal features that discriminate between specific strategies in particular plane. We identified intrahemispheric coherences in occipital–parietal and temporal–parietal areas as the most discriminative features. They have 10% lower error rate compared to single electrode features adopted in previous studies. The behavioral analysis revealed that 11% of participants switched from egocentric to allocentric strategy in a vertical plane, while 24% of participants consistently adopted egocentric strategy in both planes.
Manipulating accumulative functions by swapping call-time and return-time computations
Authors: MORIHATA AKIMASA , KAKEHI KAZUHIKO , HU ZHENJIANG , TAKEICHI MASATO
Published: May 2012

Functional languages are suitable for transformational developments of programs. However, accumulative functions, or in particular tail-recursive functions, are known to be less suitable for manipulation. In this paper, we propose a program transformation named “IO swapping” that swaps call-time and return-time computations. It moves computations in accumulative parameters to results and thereby enables interesting transformations. We demonstrate effectiveness of IO swapping by several applications: deforestation, higher order removal, program inversion, and manipulation of circular programs.
Extending modal transition systems with structured labels
Authors: BAUER SEBASTIAN S. , JUHL LINE , LARSEN KIM G. , LEGAY AXEL , SRBA JIŘÍ
Published: May 2012

We introduce a novel formalism of label-structured modal transition systems that combines the classical may/must modalities on transitions with structured labels that represent quantitative aspects of the model. On the one hand, the specification formalism is general enough to include models like weighted modal transition systems and allows system developers to employ more complex label refinement than in previously studied theories. On the other hand, the formalism maintains the desirable properties required by any specification theory supporting compositional reasoning. In particular, we study modal and thorough refinement, determinisation, parallel composition, conjunction, quotient and logical characterisation of label-structured modal transition systems.
A duality between exceptions and states
Authors: DUMAS JEAN-GUILLAUME , DUVAL DOMINIQUE , FOUSSE LAURENT , REYNAUD JEAN-CLAUDE
Published: May 2012

In this short note we study the semantics of two basic computational effects, exceptions and states, from a new point of view. In the handling of exceptions we dissociate the control from the elementary operation that recovers from the exception. In this way it becomes apparent that there is a duality, in the categorical sense, between exceptions and states.
Performance Validity and Symptom Validity in Neuropsychological Assessment
Authors: Larrabee Glenn J.
Published: May 2012

Failure to evaluate the validity of an examinee's neuropsychological test performance can alter prediction of external criteria in research investigations, and in the individual case, result in inaccurate conclusions about the degree of impairment resulting from neurological disease or injury. The terms performance validity referring to validity of test performance (PVT), and symptom validity referring to validity of symptom report (SVT), are suggested to replace less descriptive terms such as effort or response bias. Research is reviewed demonstrating strong diagnostic discrimination for PVTs and SVTs, with a particular emphasis on minimizing false positive errors, facilitated by identifying performance patterns or levels of performance that are atypical for bona fide neurologic disorder. It is further shown that false positive errors decrease, with a corresponding increase in the positive probability of malingering, when multiple independent indicators are required for diagnosis. The rigor of PVT and SVT research design is related to a high degree of reproducibility of results, and large effect sizes of d=1.0 or greater, exceeding effect sizes reported for several psychological and medical diagnostic procedures. (JINS, 2012, 18, 1–7)
Symptom Validity Testing, Effort, and Neuropsychological Assessment
Authors: Bigler Erin D.
Published: May 2012

Symptom validity testing (SVT) has become a major theme of contemporary neuropsychological research. However, many issues about the meaning and interpretation of SVT findings will require the best in research design and methods to more precisely characterize what SVT tasks measure and how SVT test findings are to be used in neuropsychological assessment. Major clinical and research issues are overviewed including the use of the “effort” term to connote validity of SVT performance, the use of cut-scores, the absence of lesion-localization studies in SVT research, neuropsychiatric status and SVT performance and the rigor of SVT research designs. Case studies that demonstrate critical issues involving SVT interpretation are presented. (JINS, 2012,18, 1–11)
Infant and young child feeding practices and child undernutrition in Bangladesh: insights from nationally representative data
Authors: Zongrone Amanda , Winskell Kate , Menon Purnima
Published: May 2012

Objective

To determine the association between indicators of infant and young child feeding (IYCF) and anthropometric measures of nutritional status among children aged 0–23 months in a nationally representative data set.

Design

Data from the 2007 Bangladesh Demographic and Health Survey were used. Analyses were conducted using multiple linear regression and logistic regression analyses adjusted for the complex survey design of the survey, controlling for child, maternal and household characteristics, and including regional dummy variables.

Setting

Bangladesh.

Subjects

Pairs (n 2096) of last born infants and their mothers.

Results

Exclusive breast-feeding under 6 months of age was associated with higher weight-for-height Z-score (effect size (ES) = 0·29; P < 0·05). Appropriate complementary feeding in children aged 6–8 months was associated with higher height-for-age Z-score (HAZ; ES = 0·63; P < 0·01) and higher weight-for-age Z-score (WAZ; ES = 0·30; P < 0·05). Higher dietary diversity index (DDI) was associated with higher HAZ (ES = 0·08; P < 0·01 for every 1 point higher DDI) and higher WAZ (ES = 0·04; P < 0·05). Children who achieved minimum diet diversity had higher HAZ (ES = 0·20; P < 0·05). Logistic regression models confirmed that exclusive breast-feeding was protective against wasting and DDI was protective against stunting and underweight.

Conclusions

Our results highlight the importance of IYCF practices as determinants of child growth outcomes in this context, and reinforce the need for interventions that address the spectrum of IYCF practices, from exclusive breast-feeding to age-appropriate complementary feeding, especially diet diversity, in efforts to improve nutrition of infants and young children.
Sales effects of product health information at points of purchase: a systematic review
Authors: van 't Riet Jonathan
Published: May 2012

Objective

Information about healthy and unhealthy nutrients is increasingly conveyed at the point of purchase. Many studies have investigated the effects of product health information on attitudes and intentions, but the empirical evidence becomes sketchier when the focus of research is actual purchase behaviour. The present paper provides an overview of empirical evidence on the effectiveness of product health information for food products at the point of purchase.

Design

A systematic literature review was conducted.

Setting

Only studies were included that assessed the effect of product health information at the point of purchase on actual purchase behaviour, using data provided by stores’ sales records or obtained by investigating customer receipts as the primary outcome measure.

Subjects

The included studies’ target group comprised supermarket clientele.

Results

Several studies found no significant effects of product health information on actual purchase behaviour. Interventions were more likely to be effective when they lasted for a longer time, when they included additional intervention components, and when they targeted the absence of unhealthy nutrients instead of or in addition to the presence of healthy nutrients.

Conclusions

No strong evidence for the effectiveness of product health information was found. The effect of intervention duration, additional promotional activities and targeting of healthyv. unhealthy nutrients should be closely examined in future studies.
Reversion from organic to conventional agriculture: A review
Authors: Sahm Henriette , Sanders Jürn , Nieberg Hiltrud , Behrens Gesine , Kuhnert Heike , Strohm Renate , Hamm Ulrich
Published: May 2012

Over the past 10 years, the organic sector has expanded continuously in Europe due to policy support and a growing market demand for organic products. In line with this development, many farmers converted to organic farming each year. Nevertheless, the total number of organic farms has not increased constantly in Europe. In several countries, the absolute number of organic farms actually decreased in some years of the past decade. Some of the deregistered farmers gave up completely; others reverted to conventional agriculture. Against this background, this article aims (i) to give an overview of the extent of reversion to conventional agriculture in Europe based on statistics, (ii) to conceptualize the decision to revert in the form of a theoretical model, (iii) to compare farmers’ reasons to revert to conventional farming based on existing studies, and (iv) to identify further research needs. The importance of reversions to conventional agriculture is difficult to determine with the existing data, especially as in most cases it is not recorded as to what happened to the farms after deregistering from organic certification. The data nevertheless show that there are large fluctuations in the organic sector with many farmers entering and exiting each year. In order to reveal the farmers’ reasons for deregistering, various qualitative as well as quantitative surveys have been carried out already. For most farmers, the decision to revert is a result of different factors. Reasons for the reversion of their farms can be classified into economic motives, difficulties regarding certification and control, problems with organic production techniques as well as the farms’ macro environment. In most cases, however, economic reasons played a main role. Suggestions for organic legislation bodies, advisory services and policy makers are derived out of the findings. A deeper understanding of the influencing aspects regarding reversions and the necessary changes in the organic sector to avoid them should be an important objective of forthcoming research.
Comparison of crop management strategies involving crop genotype and weed management practices in conventional and more diverse cropping systems
Authors: Gómez Robin , Liebman Matt , Sundberg David N. , Chase Craig A.
Published: May 2012

Cropping systems that include forage legumes and small grains in addition to corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] can achieve similar or higher crop productivity and economic return than simpler corn–soybean rotations. We hypothesized that this rotation effect occurs regardless of the crop genotype planted and the herbicide and cultivation regime selected for weed management. To test this hypothesis, we conducted a 3-year experiment that compared three cropping systems: a conventional 2-year corn–soybean rotation, a 3-year corn–soybean–oat (Avena sativa L.)/red clover (Trifolium pretense L.) rotation, and a 4-year corn–soybean–oat/alfalfa–alfalfa (Medicago sativa L.) rotation. Within each cropping system, two contrasting sets of management strategies were used: (i) genetically engineered corn with resistance to insect pests (Ostrinia nubilalis Hübner and Diabrotica spp.) plus the broadcast application of pre-emergence herbicides, followed in the rotation by a genetically engineered soybean variety with resistance to the herbicide glyphosate plus the post-emergence broadcast application of glyphosate; and (ii) non-genetically engineered corn plus the banded application of post-emergence herbicides, followed in the rotation by a non-genetically engineered soybean and banded application of several post-emergence herbicides. The two management strategies were identified as ‘GE’ and ‘non-GE.’ Corn yield was higher in the 3-year (12.51Mgha−1) and 4-year (12.79Mgha−1) rotations than in the conventional 2-year (12.16Mgha−1) rotation, and was also 2% higher with the GE strategy than with the non-GE strategy. Soybean yield was similar among rotation systems in 2008, but higher in the 3- and 4-year systems than the 2-year rotation in 2009 and 2010. Soybean yield was similar between management strategies in 2008, but higher in the GE strategy in 2009, and similar between strategies in the 3- and 4-year rotations in 2010. Increases in rotation length were accompanied by 88–91% reductions in synthetic N fertilizer application, and the use of the non-GE rather than the GE strategy was accompanied by a 93% reduction in herbicide active ingredients applied. Averaged over the period of 2008–2010, net returns to land and labor were highest for the 3-year rotation managed with either the GE ($928ha−1yr−1) or non-GE ($936ha−1yr−1) strategies, least in the 2-year rotation managed with the non-GE strategy ($738ha−1yr−1), and intermediate in the other rotation×management combinations. Our results indicate that more diverse crop rotation systems can be as profitable as conventional corn–soybean systems and can provide farmers with greater flexibility in crop management options.
What's therapeutic about the therapeutic relationship? A hypothesis for practice informed by Perceptual Control Theory
Authors: Carey Timothy A. , Kelly Rebecca E. , Mansell Warren , Tai Sara J.
Published: May 2012

Evidence clearly suggests that the therapeutic relationship is important to successful outcomes in psychotherapy. It is less clear as to why this might be the case. Throughout the literature, various factors such as warmth, empathy, compassion, unconditional positive regard, and openness are identified as key. The way in which factors such as warmth and empathy bring about an amelioration of psychological distress, however, is not entirely obvious. We suggest that one possible mechanism through which these factors become important is by helping to create an environment where clients can examine their problems freely. Furthermore, we propose that when the therapeutic relationship is therapeutic, clients feel comfortable to consider whatever comes into their mind; with any filtering or evaluating happening after the ideas have been expressed, and not before. Psychological processes identified as maintaining psychological distress (e.g. thought suppression, avoidance, rumination) block this capacity. Our suggestion is that as internal experiences are being examined, the client has an opportunity to become aware of facets of the problem that were previously unattended to; and to continue this process outside therapy. Through this awareness-raising process the client's problem can be reorganized via intrinsic learning processes to achieve a more contented state of mind.
Integration of non-linear, radiation, and propagation CAD techniques for MIMO link design
Authors: Rizzoli Vittorio , Costanzo Alessandra , Masotti Diego , Aldrigo Martino , Donzelli Francesco , Esposti Vittorio Degli
Published: May 2012

The paper outlines an exhaustive computer-aided design (CAD) procedure for the circuit-level simulation of entire multi-input multi-output (MIMO) links. The multiple transmitting and receiving antennas are treated as multiport radiating systems characterized by electromagnetic (EM) analysis. The effects of mutual couplings in terms of the frequency-dependent near-field and far-field performance of each element are accounted for in a straightforward and rigorous way. The set of transmitters is treated as a unique non-linear system loaded by the multiport antenna, and is analyzed by non-linear circuit techniques. The same is done for the set of receivers. In order to establish the connection between transmitters and receivers, the radiated far-field is evaluated by EM analysis, and the field incident on each receiver antenna is computed by extending to the MIMO case an available ray tracing technique. EM theory is then used to describe the receiving array as a linear active multiport network. This technique allows analysis of several MIMO systems, exploiting different array element spatial locations and frequencies of operation in a straightforward and automatic way. Bit error rate (BER) computation and minimization are demonstrated at the circuit level.
Analysis of totem-pole drivers in SiGe for RF and wideband applications
Authors: Wickert Michael , Wolf Robert , Ellinger Frank
Published: May 2012

This paper presents an analysis of totem-pole (TP) stages for driver applications and summarizes the major design constraints for an optimization with respect to P1dB, OIP3, and bandwidth. It is shown, that for matched drivers, in contrast to the widely applied common collector (CC) stage, class-AB TP stages offer higher output power and much higher power-added efficiencies (PAE) at comparable bandwidth. A combiner chip in 0.25 μm SiGe Bipolar CMOS (BiCMOS) verifying this concept in hardware as output driver is demonstrated proofing the increased achievable output power, which was measured greater than +0.1 dBm. This is approximately 11 dB higher than for a conventional CC driver. Furthermore, a concept is proposed, where the TP stage can act as a broadband matched driver for differential or balun operation ranging down to DC. As verification a broadband driver design using a class-AB TP stage is presented, which has a 3 dB bandwidth of 7.9 GHz and delivers up to +4.3 dBm into a 50 Ω load, which is 17 dB higher than its CC counterpart. At this output power it consumes a DC power of 12.3 mW and yields a PAE of 16.1%.
Some OFDM waveforms for a fully polarimetric weather radar
Authors: van Genderen Piet , Krasnov Oleg A. , Wang Zongbo , Tigrek Recep Firat
Published: May 2012

Retrieval of cloud parameters in weather radar benefits from polarimetric measurements. Most polarimetric radars measure the full backscatter matrix (BSM) using a few alternating polarized sounding signals. Using specially encoded orthogonal frequency division multiplexing (OFDM) signals however, the BSM can be measured in a single simultaneous transmission of two orthogonally polarized signals. Based on a set of parameters for weather radar, the properties of such a signal are explored and its merit as a useful capability is shown.
Enhancing sensitivity for emitter geolocation
Authors: Tengstrand Göran , Hultman Peter , Grandin Jean-François , Benvenuti Dario , Andersson Börje , Johansson Anders
Published: May 2012

Angle of arrival (AOA), time of arrival (TOA), and frequency of arrival (FOA) can be measured for a signal from multiple platforms. By combining such measurements it is possible to obtain high-accuracy emitter position estimates. This requires a data link with low latency and sufficient data-rate, and synchronization of the platforms in space, time, and search pattern. Typically several of the platforms will have to make their measurements in the radar sidelobes that require very high receiver sensitivity. This paper focuses on discussing how the sensitivity can be improved using antenna gain or signal processing.
Dipole tilt control of the magnetopause for southward IMF from global magnetohydrodynamic simulations
Authors: Liu Z.‐Q. , Lu J. Y. , Kabin K. , Yang Y. F. , Zhao M. X. , Cao X.
Published: May 2012

Numerical results from a physics‐based global magnetohydrodynamic (MHD) model are used to examine the effect of the dipole tilt angle (ψ) on the location and shape of the magnetopause. Identification of the magnetopause location in the simulation domain is automated using criteria based on the current density and the shape of the streamlines. These data are fitted with a three‐dimensional surface controlled by 10 configuration parameters which allow description of the cusp geometry as well as the asymmetry in the Z direction and the azimuthal asymmetry of the magnetopause. Effects of dipole tilt angle on the configuration parameters are analyzed from a series of simulations for southward IMF and different dipole tilt angle values. It is found that dipole tilt angle has little impact on the equatorial magnetopause but significantly affects the cusp locations and the degree of asymmetry between the Northern and Southern hemispheres and the equatorial/meridional plane. The results are shown to be consistent with three frequently used empirical models derived from satellite observations.
Imaging the crustal structure of the Central Iberian Zone (Variscan Belt): The ALCUDIA deep seismic reflection transect
Authors: Martínez Poyatos D. , Carbonell R. , Palomeras I. , Simancas J. F. , Ayarza P. , Martí D. , Azor A. , Jabaloy A. , González Cuadra P. , Tejero R. , Martín Parra L. M. , Matas J. , González Lodeiro F. , Pérez‐Estaún A. , García Lobón J. L. , Mansilla L.
Published: May 2012

ALCUDIA is a 230 km long, vertical incidence deep seismic reflection transect acquired in spring 2007 across the southern Central Iberian Zone (part of the pre‐Mesozoic Gondwana paleocontinent) of the Variscan Orogen of Spain. The carefully designed acquisition parameters resulted in a 20 s TWTT deep, 60–90 fold, high‐resolution seismic reflection transect. The processed image shows a weakly reflective upper crust (the scarce reflectivity matching structures identified at surface), a thick, highly reflective and laminated lower crust, and a flat Moho located at 10 s TWTT (∼30 km depth). The transect can be divided into three segments with different structural styles in the lower crust. In the central segment, the lower crust is imaged by regular, horizontal and parallel reflectors, whereas in the northern and southern segments it displays oblique reflectors interpreted as an important thrust (north) and tectonic wedging involving the mantle (south). The ALCUDIA seismic image shows that in an intracontinental orogenic crust, far from the suture zones, the upper and lower crust may react differently to shortening in different sectors, which is taken as evidence for decoupling. The interpreted structures, as deduced from surface geology and the seismic image, show that deformation was distributed homogeneously in the upper crust, whereas it was concentrated in wedge/thrust structures at specific sectors in the lower crust. The seismic image also shows the location of late Variscan faults in spatial association with the lower crustal thickened areas.
Ecosystem processes at the watershed scale: Hydrologic vegetation gradient as an indicator for lateral hydrologic connectivity of headwater catchments
Authors: Hwang Taehee , Band Lawrence E. , Vose James M. , Tague Christina
Published: May 2012

Lateral water flow in catchments can produce important patterns in water and nutrient fluxes and stores and also influences the long‐term spatial development of forest ecosystems. Specifically, patterns of vegetation type and density along hydrologic flow paths can represent a signal of the redistribution of water and nitrogen mediated by lateral hydrologic flow. This study explores the use of emergent vegetation patterns to infer ecohydrologic processes and feedbacks in forested headwater catchments. We suggest a hydrologic gradient of vegetation density as an indicator of lateral connectivity within headwater catchments. We define the hydrologic vegetation gradient (HVG) as the increase of normalized difference vegetation index per unit increase of the topographic wetness index. HVG are estimated in different headwater catchments in the Coweeta Hydrologic Laboratory using summer IKONOS imagery. We use recession slope analysis with gauge data and a distributed ecohydrological model to characterize the patterns of seasonal flow regimes within the catchments. Correlations between HVG, catchment runoff, early recession parameters, and model parameters show the interactive role of vegetation and lateral hydrologic connectivity of systems in addition to climatic and geomorphic controls. This suggests that HVG effectively represents the level of partitioning between localized water use and lateral water flow along hydrologic flow paths, especially during the growing season. It also presents the potential to use simple remotely sensed hydrologic vegetation gradients as an indicator of lateral hydrologic connectivity to extrapolate recession behavior and key model parameters of distributed hydrological models for ungauged headwater catchments.
Causes for decadal variations of wind speed over land: Sensitivity studies with a global climate model
Authors: Bichet A. , Wild M. , Folini D. , Schär C.
Published: May 2012

Over the past 30 years, observations indicate a decline of about −0.3 m/s in the northern mid‐latitudes land surface wind speed. The picture is less conclusive for the Southern Hemisphere and over the oceans. Such a stilling can affect surface evaporation and climate feedback processes, and may impact technical applications such as wind power. Using an atmospheric global climate model, we perform sensitivity experiments for the period 1870–2005 to assess the role of changing roughness length, aerosol emissions, sea surface temperature, and greenhouse gas concentrations in surface wind speed changes. The wind speed trends simulated by the model generally underestimate the observed trends (land and ocean). Over land, the model can reproduce the observed stilling by increasing the roughness length by a factor of 1.2 to 4.9, depending on region. The other forcings examined can also decrease the 10 m wind speeds (up to 15% of observed values in Europe), particularly those related to increasing aerosol emissions (up to −0.2 m/s in India). Compared to observations, the simulated impact of climate forcings on global wind speeds over land and ocean is however small and not always significant.
Paleoearthquakes of the past 30,000 years along the North Tehran Fault (Iran)
Authors: Ritz J.‐F. , Nazari H. , Balescu S. , Lamothe M. , Salamati R. , Ghassemi A. , Shafei A. , Ghorashi M. , Saidi A.
Published: May 2012

The North Tehran Fault (NTF) is located at the southernmost piedmont of Central Alborz and crosses the northern suburbs of the Tehran metropolis and adjacent cities, where ∼15 million people live. Extending over a length of about 110 km, the NTF stands out as a major active fault and represents an important seismic hazard for the Iranian capital after historical seismicity. In order to characterize the activity of the NTF in terms of kinematics, magnitude and recurrence intervals of earthquakes, we carried out a first paleoseismological study of the fault within its central part between Tehran and Karaj cities. We opened a trench across a 3 m‐high fault scarp affecting Quaternary deposits. Our study shows that the scarp is the result of repeated events along a main N115°E trending shallow dipping thrust fault, associated with secondary ruptures. From the trench analysis and Infrared Stimulated Luminescence (IRSL) dating of fault‐related sediments, we interpreted between 6 and 7 surface‐rupturing events that occurred during the past 30 kyrs. Their magnitudes (estimated from the displacements along the faults) are comprised between 6.1 and 7.2. The two last events – the largest ‐ occurred during the past 7.9 ± 1.2 ka, which yields a Holocene slip rate of ∼0.3 mm/yr. The 7 earthquakes scenario suggests a regular periodicity with a mean recurrence interval of ∼3.8 kyrs. However, the two most recent events could correspond to the two largest historical earthquakes recorded in the area (in 312–280 B.C. and 1177 A.D.), and therefore suggest that the NTF activity is not regular.
CDK targeting of NBS1 promotes DNA‐end resection, replication restart and homologous recombination
Authors: Falck Jacob , Forment Josep V , Coates Julia , Mistrik Martin , Lukas Jiri , Bartek Jiri , Jackson Stephen P
Published: May 2012

The conserved MRE11–RAD50–NBS1 (MRN) complex is an important sensor of DNA double‐strand breaks (DSBs) and facilitates DNA repair by homologous recombination (HR) and end joining. Here, we identify NBS1 as a target of cyclin‐dependent kinase (CDK) phosphorylation. We show that NBS1 serine 432 phosphorylation occurs in the S, G2 and M phases of the cell cycle and requires CDK activity. This modification stimulates MRN‐dependent conversion of DSBs into structures that are substrates for repair by HR. Impairment of NBS1 phosphorylation not only negatively affects DSB repair by HR, but also prevents resumption of DNA replication after replication‐fork stalling. Thus, CDK‐mediated NBS1 phosphorylation defines a molecular switch that controls the choice of repair mode for DSBs.
External Fixation of Unstable, “Flail” Nasal Fractures
Authors: Anastassov George E. , Payami Ali , Manji Zain
Published: May 2012

Nasal bone fractures are the most common among facial fractures. Usually these are adequately treated with closed reduction and internal and/or external stabilization with splints. However, there are clinical situations where the nasal bones are severely displaced, the nasal septum fractured and displaced, or there are external drape lacerations which preclude the use of nasal splints. If the nasal bones are reducible but unstable we consider them “flail” and in this case transmucosal, endonasal Kirschner wires are used for dorsal support until sufficient healing occurs. The technique is simple, quick, and predictable and causes minimal discomfort to the patients.
Spiral Intermaxillary Fixation
Authors: Kumar Yuvika Raj , Chaudhary Zainab , Sharma Pankaj
Published: May 2012

Intermaxillary fixation (IMF) remains an important component in the management of many facial fractures. During IMF, dental occlusion plays an important role as a guide and therapeutic tool. Since time immemorial there is a constant quest of oral and maxillofacial surgeons to find a quick way for IMF. The desire to develop an alternate interdental fixation technique, which not only would decrease the risk to the operator and gingival trauma but also accurately satisfy dental occlusion, lead to the development of this novel technique of “spiral IMF.”
Electron attachment to molecules in a cluster environment
Authors: Fabrikant I. I. , Caprasecca S. , Gallup G. A. , Gorfinkiel J. D.
Published: May 2012

Low-energy dissociative electron attachment (DEA) to the CF2Cl2 and CF3Cl molecules in a water cluster environment is investigated theoretically. Calculations are performed for the water trimer and water hexamer. It is shown that the DEA cross section is strongly enhanced when the attaching molecule is embedded in a water cluster, and that this cross section grows as the number of water molecules in the cluster increases. This growth is explained by a trapping effect that is due to multiple scattering by water molecules while the electron is trapped in the cluster environment. The trapping increases the resonance lifetime and the negative ion survival probability. This confirms qualitatively existing experiments on electron attachment to the CF2Cl2 molecule placed on the surface of H2O ice. The DEA cross sections are shown to be very sensitive to the position of the attaching molecule within the cluster and the orientation of the electron beam relative to the cluster.
Low-temperature, site selective graphitization of SiC via ion implantation and pulsed laser annealing
Authors: Lemaitre Maxime G. , Tongay Sefaattin , Wang Xiaotie , Venkatachalam Dinesh K. , Fridmann Joel , Gila Brent P. , Hebard Arthur F. , Ren Fan , Elliman Robert G. , Appleton Bill R.
Published: May 2012

A technique is presented to selectively graphitize regions of SiC by ion implantation and pulsed laser annealing (PLA). Nanoscale features are patterned over large areas by multi-ion beam lithography and subsequently converted to few-layer graphene via PLA in air. Graphitization occurs only where ions have been implanted and without elevating the temperature of the surrounding substrate. Samples were characterized using Raman spectroscopy, ion scattering/channeling, SEM, and AFM, from which the degree of graphitization was determined to vary with implantation species, damage and dose, laser fluence, and pulsing. Contrasting growth regimes and graphitization mechanisms during PLA are discussed.
Ion velocity and plasma potential measurements of a cylindrical cusped field thruster
Authors: MacDonald N. A. , Young C. V. , Cappelli M. A. , Hargus W. A.
Published: May 2012

Measurements of the most probable time-averaged axial ion velocities and plasma potential within the acceleration channel and in the plume of a straight-channeled cylindrical cusped field thruster operating on xenon are presented. Ion velocities for the thruster are derived from laser-induced fluorescence measurements of the 5d[4]7/2-6p[3]5/2 xenon ion excited state transition centered at λ=834.72nm. Plasma potential measurements are made using a floating emissive probe with a thoriated-tungsten filament. The thruster is operated in a power matched condition with 300 V applied anode potential for comparison to previous krypton plasma potential measurements, and a low power condition with 150 V applied anode potential. Correlations are seen between the plasma potential drop outside of the thruster and kinetic energy contours of the accelerating ions.
On the practicability of pentamode mechanical metamaterials
Authors: Kadic Muamer , Bückmann Tiemo , Stenger Nicolas , Thiel Michael , Wegener Martin
Published: May 2012

Conceptually, all conceivable three-dimensional mechanical materials can be built from pentamode materials. Pentamodes also enable to implement three-dimensional transformation elastodynamics—the analogue of transformation optics. However, pentamodes have not been realized experimentally. Here, we investigate inasmuch the pentamode theoretical ideal suggested by Milton and Cherkaev in 1995 can be approximated by a metamaterial with current state-of-the-art lithography. Using numerical calculations calibrated by our fabricated three-dimensional microstructures, we find that the figure of merit, i.e., the ratio of bulk modulus to shear modulus, can realistically be made as large as about 1000.
Generation of acoustic pulses from a photo-acoustic transducer measured by time-resolved x-ray diffraction
Authors: Gao Yuan , DeCamp Matthew F.
Published: May 2012

Picosecond acoustic pulses generated by ultrafast optical excitation of a 100 nm gold photo-acoustic transducer deposited on a germanium substrate are observed using time-resolved x-ray diffraction. The resulting pump-probe spectra reveal that the spatiotemporal structure of the acoustic pulse is bipolar with acoustic wavevectors up to inverse of the film thickness.
Key capacitive parameters for designing single-electron transistor charge sensors
Authors: Horibe Kosuke , Kodera Tetsuo , Kambara Tomohiro , Uchida Ken , Oda Shunri
Published: May 2012

Single-electron transistors (SETs) are efficient charge sensors for reading out spin or charge qubits confined in quantum dots (QDs). To investigate their capacitive parameters, which are related to the signal-to-noise ratio (SNR) during qubit readout, twin silicon single QDs were fabricated using a lithographic process on a silicon-on-insulator substrate. Since the configuration and dimensions of the QDs could be determined by direct imaging, the theoretical capacitive parameters could be compared to the measured values. Good agreement was found between the calculated and measured values, which confirms the validity of the calculation method. The results indicated that decreasing the SET diameter reduces the capacitive coupling between qubits but increases the signal-to-noise ratio for both dc and radio frequency single-shot measurements. Since these results are independent of the device materials, they are useful for establishing guidelines for the design of SET charge sensors in lateral QD-SET structures based on a two-dimensional electron gas.
Generation and annihilation of domain walls in nanowires by localized fields
Authors: Stein Falk-Ulrich , Bocklage Lars , Matsuyama Toru , Meier Guido
Published: May 2012

We study the creation and annihilation of domain walls in a permalloy nanowire by local Oersted fields of current pulses passing through a perpendicularly aligned stripline. The occurrence of both processes is investigated for current pulses of different polarities and for various external magnetic fields. Reliable creation and annihilation are achieved for small and zero external fields, while higher externally applied fields lead to the suppression of both processes as well as to the creation of multiple domain walls in the wire.
Turn-on spread determines the size of the switching region in an avalanche transistor
Authors: Duan Guoyong , Vainshtein Sergey , Kostamovaara Juha
Published: May 2012

It has been shown recently that only a small part of the emitter-base interface in a Si bipolar junction transistor participates in short-pulsing avalanche switching. This lateral current shrinkage attributed to the “winner takes all” effect reduces the transistor switching size from 1600 to ∼100 μm, still remaining much larger than the transistor structure thickness. We show using quasi-3-D transient modelling that the size of the operating perimeter, which is critically important for switching efficiency and device reliability, is determined by competition between lateral turn-on shrinkage and spread. The latter has never been demonstrated in avalanche transistors before.
Optimizing fiber cross-sectional shape for improving stability of air–water interface over superhydrophobic fibrous coatings
Authors: Emami B. , Tafreshi H. Vahedi
Published: May 2012

In this letter, a mathematical force-balance formulation is developed that can be used to predict the critical pressure, the hydrostatic pressure above which the surface starts to depart from the non-wetting state, for superhydrophobic surfaces comprised of highly aligned fibers (e.g., biased AC-electrospun coatings) with arbitrary cross-sectional shapes. We have also developed a methodology for optimizing the fiber cross-sections to maximize the critical pressure of the surface, using the Euler–Lagrange equation. A case study is presented to better demonstrate the application of our method.