bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid crystal films as on-demand, variable thickness (50–5000 nm) targets for intense lasers
Authors: Poole P. L. , Andereck C. D. , Schumacher D. W. , Daskalova R. L. , Feister S. , George K. M. , Willis C. , Akli K. U. , Chowdhury E. A.
Published: June 2014

We have developed a new type of target for intense laser-matter experiments that offers significant advantages over those currently in use. The targets consist of a liquid crystal film freely suspended within a metal frame. They can be formed rapidly on-demand with thicknesses ranging from nanometers to micrometers, where the particular value is determined by the liquid crystal temperature and initial volume as well as by the frame geometry. The liquid crystal used for this work, 8CB (4′-octyl-4-cyanobiphenyl), has a vapor pressure below 10−6 Torr, so films made at atmospheric pressure maintain their initial thickness after pumping to high vacuum. Additionally, the volume per film is such that each target costs significantly less than one cent to produce. The mechanism of film formation and relevant physics of liquid crystals are described, as well as ion acceleration data from the first shots on liquid crystal film targets at the Ohio State University Scarlet laser facility.
Modeling carbon nanotube growth on the catalyst-substrate surface subjected to reactive plasma
Authors: Tewari Aarti , Sharma Suresh C.
Published: June 2014

The paper presents a theoretical model to study the growth of the carbon nanotube (CNT) on the catalyst substrate surface subjected to reactive plasma. The charging rate of the CNT, kinetics of electron, ions and neutral atoms, the growth rate of the CNT because of diffusion and accretion of ions on the catalyst nanoparticle inclusion of the issue of the plasma sheath is undertaken in the present model. Numerical calculations on the effect of ion density and temperature and the substrate bias on the growth of the CNT have been carried out for typical glow discharge plasma parameters. It is found that the height of CNT increases with the ion density of carbon ions and radius of CNT decreases with hydrogen ion density. The substrate bias also affects the growth rate of the CNT. The field emission characteristics from the CNTs can be analyzed from the results obtained.
Real time voltage control using emergency demand response in distribution system by integrating advanced metering infrastructure
Authors: Homaee Omid , Zakariazadeh Alireza , Jadid Shahram
Published: June 2014

In this paper, an analytical study is reported to demonstrate the effects of demand response on distribution network voltages profile. Also, a new approach for real time voltage control is proposed which uses emergency demand response program aiming at maintaining voltage profile in an acceptable range with minimum cost. This approach will be active in emergency conditions where, in real time, the voltages in some nodes leave their permissible ranges. These emergency conditions are Distributed Generation (DG) units and lines outage, and unpredictable demand and renewable generations' fluctuations. The proposed approach does not need the load and renewable generation forecast data to regulate voltage. To verify the effectiveness and robustness of the proposed control scheme, the proposed voltage control scheme is tested on a typical distribution network. The simulation results show the effectiveness and capability of the proposed real time voltage control model to maintain smart distribution network voltage in specified ranges in both normal and emergency conditions.
Multi-fluid transport code modeling of time-dependent recycling in ELMy H-mode
Authors: Pigarov A. Yu. , Krasheninnikov S. I. , Rognlien T. D. , Hollmann E. M. , Lasnier C. J. , Unterberg E.
Published: June 2014

Simulations of a high-confinement-mode (H-mode) tokamak discharge with infrequent giant type-I ELMs are performed by the multi-fluid, multi-species, two-dimensional transport code UEDGE-MB, which incorporates the Macro-Blob approach for intermittent non-diffusive transport due to filamentary coherent structures observed during the Edge Localized Modes (ELMs) and simple time-dependent multi-parametric models for cross-field plasma transport coefficients and working gas inventory in material surfaces. Temporal evolutions of pedestal plasma profiles, divertor recycling, and wall inventory in a sequence of ELMs are studied and compared to the experimental time-dependent data. Short- and long-time-scale variations of the pedestal and divertor plasmas where the ELM is described as a sequence of macro-blobs are discussed. It is shown that the ELM recovery includes the phase of relatively dense and cold post-ELM divertor plasma evolving on a several ms scale, which is set by the transport properties of H-mode barrier. The global gas balance in the discharge is also analyzed. The calculated rates of working gas deposition during each ELM and wall outgassing between ELMs are compared to the ELM particle losses from the pedestal and neutral-beam-injection fueling rate, correspondingly. A sensitivity study of the pedestal and divertor plasmas to model assumptions for gas deposition and release on material surfaces is presented. The performed simulations show that the dynamics of pedestal particle inventory is dominated by the transient intense gas deposition into the wall during each ELM followed by continuous gas release between ELMs at roughly a constant rate.
Testing epitaxial Co1.5Fe1.5Ge(001) electrodes in MgO-based magnetic tunnel junctions
Authors: Neggache A. , Hauet T. , Bertran F. , Le Fèvre P. , Petit-Watelot S. , Devolder T. , Ohresser P. , Boulet P. , Mewes C. , Maat S. , Childress J. R. , Andrieu S.
Published: June 2014

The ability of the full Heusler alloy Co1.5Fe1.5Ge(001) (CFG) to be a Half-Metallic Magnetic (HMM) material is investigated. Epitaxial CFG(001) layers were grown by molecular beam epitaxy. The results obtained using electron diffraction, X-ray diffraction, and X-ray magnetic circular dichroism are consistent with the full Heusler structure. The pseudo-gap in the minority spin density of state typical in HMM is examined using spin-resolved photoemission. Interestingly, the spin polarization found to be negative at EF in equimolar CoFe(001) is observed to shift to positive values when inserting Ge in CoFe. However, no pseudo-gap is found at the Fermi level, even if moderate magnetization and low Gilbert damping are observed as expected in HMM materials. Magneto-transport properties in MgO-based magnetic tunnel junctions using CFG electrodes are investigated via spin and symmetry resolved photoemission.
Numerical simulation: Toward the design of high-efficiency planar perovskite solar cells
Authors: Liu Feng , Zhu Jun , Wei Junfeng , Li Yi , Lv Mei , Yang Shangfeng , Zhang Bing , Yao Jianxi , Dai Songyuan
Published: June 2014

Organo-metal halide perovskite solar cells based on planar architecture have been reported to achieve remarkably high power conversion efficiency (PCE, >16%), rendering them highly competitive to the conventional silicon based solar cells. A thorough understanding of the role of each component in solar cells and their effects as a whole is still required for further improvement in PCE. In this work, the planar heterojunction-based perovskite solar cells were simulated with the program AMPS (analysis of microelectronic and photonic structures)-1D. Simulation results revealed a great dependence of PCE on the thickness and defect density of the perovskite layer. Meanwhile, parameters including the work function of the back contact as well as the hole mobility and acceptor density in hole transport materials were identified to significantly influence the performance of the device. Strikingly, an efficiency over 20% was obtained under the moderate simulation conditions.
Room temperature continuous wave lasing of electrically injected GaN-based vertical cavity surface emitting lasers
Authors: Liu Wen-Jie , Hu Xiao-Long , Ying Lei -Ying , Zhang Jiang-Yong , Zhang Bao-Ping
Published: June 2014

Continuous wave (CW) lasing of electrically injected GaN-based vertical cavity surface emitting lasers (VCSELs) was achieved at room temperature. First, a high quality factor (Q) VCSEL-structured device with very narrow linewidth of 0.12 nm, corresponding to a Q-value of 3570 was obtained through two-step substrate transfer technique. However, poor heat dissipation ability prevented the device from lasing. Based on the high-Q resonant cavity design, we further fabricated vertical-structured VCSELs through metal bonding technique on Si substrate. CW lasing from vertical-structured VCSELs was observed with threshold current of density of 1.2 kA/cm2 and lasing linewidth of about 0.20 nm.
Quantifying coherent and incoherent cathodoluminescence in semiconductors and metals
Authors: Brenny B. J. M. , Coenen T. , Polman A.
Published: June 2014

We present a method to separate coherent and incoherent contributions to cathodoluminescence from bulk materials by using angle-resolved cathodoluminescence spectroscopy. Using 5 and 30 keV electrons, we measure the cathodoluminescence spectra for Si, GaAs, Al, Ag, Au, and Cu and determine the angular emission distributions for Al, GaAs, and Si. Aluminium shows a clear dipolar radiation profile due to coherent transition radiation, while GaAs shows incoherent luminescence characterized by a Lambertian angular distribution. Silicon shows both transition radiation and incoherent radiation. From the angular data, we determine the ratio between the two processes and decompose their spectra. This method provides a powerful way to separate different radiative cathodoluminescence processes, which is useful for material characterization and in studies of electron- and light-matter interaction in metals and semiconductors.
Validation of the tunneling percolation staircase model in granular metals
Authors: Balberg I. , Azulay D. , Jedrzejewski J. , Savir E.
Published: June 2014

In this Letter, we provide conclusive evidence for a lattice like arrangement of the silver grains in the nanogranular Ag-Al2O3 metal. The evidence for the presence of clearly separated first and second near neighbor grains was derived from the electrical conductivity dependence on the metallic content in these composites. The data were analyzed in light of the tunneling percolation staircase model that we have recently suggested for lattices or systems with discrete well-defined interparticle distances in the continuum.
Small-scale effect on the piezoelectric potential of gallium nitride nanowires
Authors: Zhang Jin
Published: June 2014

The small-scale effect on the piezoelectric potential of strained gallium nitride (GaN) nanowires (NWs) is studied by employing the size-dependent dielectric constant measured from the present molecular dynamics simulations and previous reported size-dependent elastic constant and piezoelectric coefficient. The intrinsic GaN NWs without free charge carriers are considered in the present study. The results show that the small-scale effect is significant for NWs in the range of nanometers and may increase the piezoelectric potential by up to a dozen times. The small-scale effect is also found to decrease with increasing NW cross-section and a critical cross-sectional size of 38 nm is obtained for almost negligible small-scale effect on the piezoelectric potential of GaN NWs. The present work can be further extended to the as-grown GaN NWs in the future by considering the free charge effect.
High carrier mobility in orientation-controlled large-grain (≥50 μm) Ge directly formed on flexible plastic by nucleation-controlled gold-induced-crystallization
Authors: Park Jong-Hyeok , Kasahara Kenji , Hamaya Kohei , Miyao Masanobu , Sadoh Taizoh
Published: June 2014

High-carrier-mobility semiconductors on flexible-plastic are essential to realize flexible electronics. For this purpose, electrical properties of orientation-controlled large-grain Ge crystals on flexible-plastic directly formed by nucleation-controlled gold-induced-crystallization (GIC) are examined, and compared with those obtained by aluminum-induced-crystallization (AIC). The Ge crystals show p-type conductions. Here, hole concentrations are 2.2 × 1017 and 5.8 × 1020 cm−3 for GIC-Ge and AIC-Ge, respectively, which are explained on the basis of the solubility of Au and Al in Ge. Thanks to the low hole concentration, GIC-Ge shows high hole mobility (160 cm2 V−1 s−1) compared with AIC-Ge (37 cm2 V−1 s−1). These demonstrate significant advantage of GIC to realize high-performance flexible-electronics.
Polarization conversions of linearly and circularly polarized lights through a plasmon-induced transparent metasurface
Authors: Shao Jian , Li Jie , Wang Ying-Hua , Li Jia-Qi , Chen Qian , Dong Zheng-Gao
Published: June 2014

Polarization control of the light can be realized by ultrathin plasmonic structures, which is generally based on the effect of extraordinary optical transmission. In this paper, we designed a U-shaped plasmon-induced transparent metasurface to investigate the polarization state conversions of resonantly transmitted light through reducing the structural symmetry by rotation. A significant optical polarization conversion capability is found for impinging light with linear as well as circular polarization. In particular, the different polarization conversions between the left-handed and right-handed circular lights manifest the characteristic of circular dichroism. The results are useful for the potential applications such as a broadband quarter-wave plate.
Multiple delta doping of single crystal cubic boron nitride films heteroepitaxially grown on (001)diamonds
Authors: Yin H. , Ziemann P.
Published: June 2014

Phase pure cubic boron nitride (c-BN) films have been epitaxially grown on (001) diamond substrates at 900 °C. The n-type doping of c-BN epitaxial films relies on the sequential growth of nominally undoped (p-) and Si doped (n-) layers with well-controlled thickness (down to several nanometer range) in the concept of multiple delta doping. The existence of nominally undoped c-BN overgrowth separates the Si doped layers, preventing Si dopant segregation that was observed for continuously doped epitaxial c-BN films. This strategy allows doping of c-BN films can be scaled up to multiple numbers of doped layers through atomic level control of the interface in the future electronic devices. Enhanced electronic transport properties with higher hall mobility (102 cm2/V s) have been demonstrated at room temperature as compared to the normally continuously Si doped c-BN films.
Tuning characteristics of mirrorlike T-shape terahertz metamaterial using out-of-plane actuated cantilevers
Authors: Lin Yu-Sheng , Lee Chengkuo
Published: June 2014

We present a mirrorlike T-shape metamaterial (MTM) with out-of-plane movable microstructures for enabling active tuning of resonant frequency in the terahertz (THz) region. The resonant frequency of MTM device can be actively controlled by using either electrostatic force or liquid force. First, by gradually increasing the bias, the cantilevers were continuously deformed towards the substrate and then completely snapped down when the bias reached the critical pull-in voltage (12 V). The tuning range is 0.50 THz as compared to the device without driving voltage to that operated at the pull-in voltage. Meanwhile, we dropped different liquids on the snap-down device surface. In the case of device covered with deionised water, the resonant frequency shift of 0.17 and 0.21 THz were measured for inductive-capacitive and dipolar resonances, respectively. Furthermore, we also demonstrate the flow tuning capability of MTM device integrated with a polydimethylsiloxane fluidic channel by using different injection flow rate from 0 to 5 ml/min. The tunability of MTM device is 0.30 THz due to the different bending states of the MTM cantilevers under different liquid forces.
GeTe sequences in superlattice phase change memories and their electrical characteristics
Authors: Ohyanagi T. , Kitamura M. , Araidai M. , Kato S. , Takaura N. , Shiraishi K.
Published: June 2014

We studied GeTe structures in superlattice phase change memories (superlattice PCMs) with a [GeTe/Sb2Te3] stacked structure by X-ray diffraction (XRD) analysis. We examined the electrical characteristics of superlattice PCMs with films deposited at different temperatures. It was found that XRD spectra differed between the films deposited at 200 °C and 240 °C; the differences corresponded to the differences in the GeTe sequences in the films. We applied first-principles calculations to calculate the total energy of three different GeTe sequences. The results showed the Ge-Te-Ge-Te sequence had the lowest total energy of the three and it was found that with this sequence the superlattice PCMs did not run.
Density gradient effects on transverse shear driven lower hybrid waves
Authors: DuBois Ami M. , Thomas Edward , Amatucci William E. , Ganguli Gurudas
Published: June 2014

Shear driven instabilities are commonly observed in the near-Earth space, particularly in boundary layer plasmas. When the shear scale length (LE) is much less than the ion gyro-radius (ρi) but greater than the electron gyro-radius (ρe), the electrons are magnetized in the shear layer, but the ions are effectively un-magnetized. The resulting shear driven instability, the electron-ion hybrid (EIH) instability, is investigated in a new interpenetrating plasma configuration in the Auburn Linear EXperiment for Instability Studies. In order to understand the dynamics of magnetospheric boundary layers, the EIH instability is studied in the presence of a density gradient located at the boundary layer between two plasmas. This paper reports on a recent experiment in which electrostatic lower hybrid waves are identified as the EIH instability, and the effect of a density gradient on the instability properties are investigated.
Public Toilets: An Exploratory Study on the Demands, Needs, and Expectations in Turkey
Authors: Afacan Yasemin , Gurel Meltem O
Published: June 2014

Provision of public toilets is not only a matter of land use, but also an essential design and planning concern. This study examines the following questions through an explanatory study. (i) What problems do public toilets pose? (ii) What toilet facilities do people require most and/or most emphasize would affect the way they use land and participate in social life? (iii) How do demands, needs, and expectations around public toilets change depending on gender, age, and ability? We conduct a survey of 300 people in fourteen public restrooms in the city centre of Ankara, Turkey. According to factor analysis results, public toilets should be seen as potential urban spaces and initial opportunities for sustainable urban developments and liveable cities.
Effects of Alternative Developer Decision-Making Models on the Production of Ecological Subdivision Designs: Experimental Results from an Agent-Based Model
Authors: Magliocca Nicholas R , Brown Daniel G , McConnell Virginia D , Nassauer Joan I , Westbrook S Elizabeth
Published: June 2014

Approaches to residential development have clear effects on the surrounding environments, including those on habitat protection, water quality, transportation and congestion costs, and loss of public open space. Ecological subdivision designs (ESDs) are a means to mitigate some of the most negative effects of low-density dispersed land-use patterns, yet there is not widespread adoption of these alternative approaches to subdivision development. In this paper we attempt to improve understanding of how developers make decisions over development designs and what influences those decisions. Using an agent-based model of residential-housing and land markets, the effects of different developer-decision frameworks on development designs and land use are assessed. The importance of uncertainty in the outcome of new designs, such as ESDs, and the effect of that uncertainty on the cost of credit are possible explanations for the prevalence of conventional, low-density development types, and may be impeding adoption of ESDs.
Effects of Attention on Visible and Invisible Adapters
Authors: Jung Yaelan , Chong Sang Chul
Published: June 2014

It has been shown that attention can modulate the processing of a stimulus, even when it is invisible (Bahrami, Carmel, Walsh, Rees, & Lavie, 2008, Perception, 37, 1520–1528). Previous studies, however, investigated the effect of spatial attention on the processing of only invisible items. Thus, it remains unclear how the effect of spatial attention is distributed over visible and invisible items when these items are simultaneously attended at the same location. In the present study we addressed this question using two types of adapters, one visible and one invisible, and compared how attention affected the processing of each adapter. Moving gratings and tilted gratings were presented to each eye; the moving ones were dominant over the tilted ones. Both types of stimuli were located on the left and right sides of a fixation cross, and the participants performed a task that modulated their attention to one side or the other. In experiment 1 they were asked to detect the contrast decrement of one of the moving gratings, and in experiment 2 they detected a dot that was presented to both eyes. We found that attention increased the amount of motion aftereffects induced by the visible adapters. However, we did not find effects of attention on tilt aftereffects from the invisible adapters. Finally, in experiment 3 we found that attention successfully increased the amount of tilt aftereffects when the adapters were not suppressed. These findings suggest that spatial attention is more likely to influence visible items than invisible items in the same location. We also found that invisible items do not interfere with the attentional modulation of the processing of visible items.
Ten clinician-driven strategies for maximising value of Australian health care
Authors: Scott Ian
Published: June 2014

Objective To articulate the concept of high-value care (i.e. clinically relevant, patient-important benefit at lowest possible cost) and suggest strategies by which clinicians can promote such care in rendering the Australian healthcare system more affordable and sustainable. Methods Strategies were developed by the author based on personal experience in clinical practice, evidence-based medicine and quality improvement. Relevant literature was reviewed in retrieving studies supporting each strategy. Results Ten strategies were developed: (1) minimise errors in diagnosis; (2) discontinue low- or no-value practices that provide little benefit or cause harm; (3) defer the use of unproven interventions; (4) select care options according to comparative cost-effectiveness; (5) target clinical interventions to those who derive greatest benefit; (6) adopt a more conservative approach nearing the end of life; (7) actively involve patients in shared decision making and self-management; (8) minimise day-to-day operational waste; (9) convert healthcare institutions into rapidly learning organisations; and (10) advocate for integrated patient care across all clinical settings. Conclusions Clinicians and their professional organisations, in partnership with managers, can implement strategies capable of maximising value and sustainability of health care in Australia. What is known about this topic? Value-based care has emerged as a unitary concept that integrates quality and cost, and is being increasingly used to inform healthcare policy making and reform. What does this paper add? There is scant literature that translates the concept of high value care into actionable enhancement strategies for clinicians in everyday practice settings. This article provides 10 strategies with supporting studies in an attempt to fill this gap. What are the implications for practitioners? If all practitioners, in partnership with healthcare managers, attempted to enact all 10 strategies in their workplaces, a significant quantum of healthcare resources could be redirected from low- to high-value care, culminating in much greater health benefit from the healthcare dollars currently being spent. However, such reforms will require a shift in clinician thinking and practice away from volume-based care to value-based care.
Molecular genetic diversity and population structure in Eucalyptus pauciflora subsp. pauciflora (Myrtaceae) on the island of Tasmania
Authors: Gauli Archana , Steane Dorothy A. , Vaillancourt René E. , Potts Brad M.
Published: June 2014

Genetic diversity and population structure of Tasmanian populations of Eucalyptus pauciflora were assessed using chloroplast and nuclear microsatellite markers. Maternal trees and open-pollinated progeny from 37 populations were sampled across the species’ geographic and altitudinal distribution in Tasmania. The distribution of chloroplast haplotype richness showed a clear geographic structure with suggestion of three major refugia (Storm Bay, Tamar Valley and St Pauls River Valley), two of which are consistent with previously reported glacial refugia. Chloroplast haplotype affinities provided evidence of migration of populations from the north and east towards the south and west of Tasmania. High nuclear microsatellite diversity was observed across the species’ range. Most of this variation was distributed within populations with low but significant FST, suggesting high gene flow among populations that is more pronounced in mature stands. Higher nuclear genetic diversity in newly colonised areas compared with lowland putative refugial regions, and the converse in chloroplast DNA markers, suggest limited seed dispersal into newly colonised regions combined with high pollen flow between different source populations in newly colonised areas. Our results do not support the suggestion that highland populations of E. pauciflora originate from in situ high-altitude refugia, but instead argue they originate from lowland refugia.
Quantitative trait locus mapping of the transpiration ratio related to preflowering drought tolerance in sorghum (Sorghum bicolor)
Authors: Kapanigowda Mohankumar H. , Payne William A. , Rooney William L. , Mullet John E. , Balota Maria
Published: June 2014

To meet future food needs, grain production must increase despite reduced water availability, so waterproductivity must rise. One way to do this is to raise the ratio of biomass produced to water transpired, which is controlled by the ratio of CO2 assimilation (A) to transpiration (E) (i.e. the transpiration ratio, A : E divided by vapour pressure deficit) or anything affecting stomatal movement.. We describe the genetic variation and basis of A, E and A : E among 70 recombinant inbred lines (RILs) of sorghum (Sorghum bicolor (L.) Moench), using greenhouse experiments. Experiment 1 used 40% and 80% of field capacity (FC) as water regimes; Experiment 2 used 80% FC. Genotype had a significant effect on A, E and A : E. In Experiment 1, mean values for A : E were 1.2–4.4 mmol CO2 mol–1 H2O kPa–1 and 1.6–3.1 mmol CO2 mol–1 H2O kPa–1 under 40% and 80% FC, respectively. In Experiment 2, values were 5.6–9.8 mmol CO2 mol–1 H2O kPa–1. Pooled data for A : E and A : E VPD–1 from Experiment 1 indicate that A : E fell quickly at temperatures >32.3°C. A : E distributions were skewed. Mean heritabilities for A : E were 0.9 (40% FC) and 0.8 (80% FC). Three significant quantitative trait loci (QTLs) associated with A:E, two on SBI-09 and one on SBI-10, accounted for 17–21% of the phenotypic variation. Subsequent experiments identified 38 QTLs controlling variation in height, flowering, biomass, leaf area, greenness and stomatal density. Colocalisation of A : E QTLs with agronomic traits indicated that these QTLs can be used for improving sorghum performance through marker assisted selection (MAS) under preflowering drought stress.
A combined equation to estimate the soil pore-water electrical conductivity: calibration with the WET and 5TE sensors
Authors: Visconti Fernando , Martínez Delfina , Molina María José , Ingelmo Florencio , Miguel de Paz José
Published: June 2014

Affordable, commercial dielectric sensors of the frequency domain reflectometry (FDR) and capacitance–conductance (CC) types estimate the dielectric permittivity (εb) and electrical conductivity (σb) of bulk soil. In this work, an equation was obtained to estimate the pore-water electrical conductivity (σp), which is closely related to the soil salinity in contact with plant roots, from εb and σb data, by combining the simplified dielectric mixing (SDM) model that relates εb to the soil volumetric water content (θ), with the Rhoades equation that relates θ and σb to σp. This equation was calibrated with measurements of εb and σb obtained with the Delta-T WET (FDR) and the Decagon 5TE (CC) sensors, in 20 pots filled with a clay loam soil and arranged as combinations of four levels of soil moisture with five levels of soil salinity. The calibrations were performed against reference θ and σp values. The σp was calculated with the chemical equilibrium model SALSOLCHEMEC and used as a more reliable reference than the electrical conductivity of the soil wetting water. For both sensors, the SDM model on the one hand, and the Rhoades equation on the other, provided the most accurate estimations using the least number of parameters regarding their respective alternatives, i.e. the third-order polynomial and the Hilhorst equation. The combined equation for estimation of σp subsequently provided root mean square deviations of 3.1 (WET) and 4.1 (5TE) dS m–1, which decreased to 1.5 and 2.6 dS m–1 for θ >0.22 m3 m–3, and σb <3 (WET) and 3.7 (5TE) dS m–1. A new combined equation has been proposed for reliable estimations of σp with these sensors in clayey soils for θ >0.22 m3 m–3 and σb <3.7 dS m–1.
Ignition and fire behaviour of Juniperus virginiana in response to live fuel moisture and fire temperature in the southern Great Plains
Authors: Weir John R. , Scasta J. Derek
Published: June 2014

Fire is the most effective tool for managing Juniperus virginiana encroachment and associated fire risk, but its application has been limited. In a laboratory experiment we assessed a critical knowledge gap: how fire temperature and live fuel moisture (LFM) influences ignitability, sustainability, combustibility and consumability of J. virginiana. Percentage occurrence of ignition rose as fire temperature increased. The time to ignition increased while the occurrence of ignition decreased with increasing LFM. LFM and fire temperature each had a significant effect on all measured dependent variables (P≤0.05) as was their interaction, except in the case of sustainability. As expected, time to flaming was shortest and flame lengths were the highest under the hottest fire and lowest LFM scenarios. Flame heights increased quadratically as LFM decreased with a critical threshold at 60% LFM. Land managers can select burning prescriptions based on the interaction between fire temperature and LFM to either increase J. virginiana ignition or reduce hazards. In this study, the low and moderate fire temperatures were similar to those of prescribed fires at low and high fuel loads and the high temperature level mimics conditions found in extreme wildfires. Thus, higher fuel loads and hotter fires are required to maximise efficacy of fires targeting J. virginiana control.
Major mouse placental compartments revealed by diffusion-weighted MRI, contrast-enhanced MRI, and fluorescence imaging
Authors: Solomon Eddy , Avni Reut , Hadas Ron , Raz Tal , Garbow Joel Richard , Bendel Peter , Frydman Lucio , Neeman Michal
Published: June 2014

Significance

Fluid motion measurements can provide valuable insight regarding the structure and function of developing placentas. This study presents to our knowledge the first MRI characterization of multicompartmental diffusion and incoherent flow in pregnant mice at different gestation stages, made possible by methods herein introduced for the single-scan acquisition of diffusion-encoded images in the challenging environment associated with in vivo embryonic studies. These methods were combined with a customized contrast agent to reveal a freely diffusive maternal blood pool, a strongly perfused fetal blood flow, and an intermediate behavior for the trophoblastic labyrinth cell layer. Structural features associated with these dynamics were corroborated with ex vivo fluorescence microscopy and are discussed within the context of the anatomical structure of developing mouse placentas.
Duration of urination does not change with body size
Authors: Yang Patricia J. , Pham Jonathan , Choo Jerome , Hu David L.
Published: June 2014

Significance

Animals eject fluids for waste elimination, communication, and defense from predators. These diverse systems all rely on the fundamental principles of fluid mechanics, which we use to predict urination duration across a wide range of mammals. In this study, we report a mathematical model that clarifies misconceptions in urology and unifies the results from 41 independent urological and anatomical studies. The theoretical framework presented may be extended to study fluid ejection from animals, a universal phenomenon that has received little attention.
Finite element error estimates on the boundary with application to optimal control
Authors: Apel Thomas , Pfefferer Johannes , Rösch Arnd
Published: June 2014

This paper is concerned with the discretization of linear elliptic partial differential equations with Neumann boundary condition in polygonal domains. The focus is on the derivation of error estimates in the

L
2

L^2

-norm on the boundary for linear finite elements. Whereas common techniques yield only suboptimal results, a new approach in this context is presented which allows for quasi-optimal ones, i.e., for domains with interior angles smaller than

2
π

/

3

2\pi /3

a convergence order two (up to a logarithmic factor) can be achieved using quasi-uniform meshes. In the presence of internal angles greater than

2
π

/

3

2\pi /3

which reduce the convergence rates on quasi-uniform meshes, graded meshes are used to maintain the quasi-optimal error bounds.

This result is applied to linear-quadratic Neumann boundary control problems with pointwise inequality constraints on the control. The approximations of the control are piecewise constant. The state and the adjoint state are discretized by piecewise linear finite elements. In a postprocessing step approximations of the continuous optimal control are constructed which possess superconvergence properties. Based on the improved error estimates on the boundary and optimal regularity in weighted Sobolev spaces almost second order convergence is proven for the approximations of the continuous optimal control problem. Mesh grading techniques are again used for domains with interior angles greater than

2
π

/

3

2\pi /3

. A certain regularity of the active set is assumed.
What Drives Commodity Prices?
Authors: Chen Shu-Ling , Jackson John D. , Kim Hyeongwoo , Resiandini Pramesti
Published: June 2014

This article examines common forces that drive the prices of 51 tradable commodities. We demonstrate that highly persistent movements of these prices are mostly due to the first common component, which is closely related to the U.S. nominal exchange rate. In particular, our simple factor‐based model outperforms the random walk model in out‐of‐sample forecast for the U.S. exchange rate. The second common factor and de‐factored idiosyncratic components are consistent with stationarity, implying short‐lived deviations from the equilibrium price dynamics. In concert, these results provide an intriguing resolution to the apparent inconsistency that arises from stable markets with nonstationary prices.
Rising Food Prices, Food Price Volatility, and Social Unrest
Authors: Bellemare Marc F.
Published: June 2014

Can food prices cause social unrest? Throughout history, riots have frequently broken out, ostensibly as a consequence of high food prices. Using monthly data at the international level, this article studies the impact of food prices – food price levels as well as food price volatility – on social unrest. Because food prices and social unrest are jointly determined, data on natural disasters are used to identify the causal relationship flowing from food price levels to social unrest. Results indicate that for the period 1990–2011, food price increases have led to increases in social unrest, whereas food price volatility has not been associated with increases in social unrest. These results are robust to alternative definitions of social unrest, to using real or nominal prices, to using commodity‐specific price indices instead of aggregated price indices, to alternative definitions of the instrumental variable, to alternative definitions of volatility, and to controlling for non‐food‐related social unrest.
Commodity Price Responses to Monetary Policy Surprises
Authors: Scrimgeour Dean
Published: June 2014

Information contained in high‐frequency financial market data reveals that a 10 basis‐point surprise increase in interest rates causes commodity prices to fall immediately by approximately 0.6%. This is similar to the estimated responses of both the Standard and Poor's 500 and a United States trade weighted exchange rate index, and approximately five times larger than the response in a standard vector autoregression, even twelve months after the shock. Metals prices tend to respond more than agricultural commodities. The point estimate for oil prices is similar to other commodities, but is estimated less precisely.
Bradyrhizobium
ottawaense sp. nov., a symbiotic nitrogen fixing bacterium from root nodules of soybeans in Canada
Authors: Yu Xiumei , Cloutier Sylvie , Tambong James T. , Bromfield Eden S. P.
Published: June 2014

Sixteen strains of symbiotic bacteria from root nodules of Glycine max grown in Ottawa, Canada, were previously characterized and placed in a novel group within the genus

Bradyrhizobium

. To verify their taxonomic status, these strains were further characterized using a polyphasic approach. All strains possessed identical 16S rRNA gene sequences that were 99.79 % similar to the closest relative,

Bradyrhizobium liaoningense

LMG 18230T. Phylogenetic analysis of concatenated atpD, glnII, recA, gyrB, rpoB and dnaK genes divided the 16 strains into three multilocus sequence types that were placed in a highly supported lineage distinct from named species of the genus

Bradyrhizobium

consistent with results of DNA–DNA hybridization. Based on analysis of symbiosis gene sequences (nodC and nifH), all novel strains were placed in a phylogenetic group with five species of the genus

Bradyrhizobium

that nodulate soybeans. The combination of phenotypic characteristics from several tests including carbon and nitrogen source utilization and antibiotic resistance could be used to differentiate representative strains from recognized species of the genus

Bradyrhizobium

. Novel strain OO99T elicits effective nodules on Glycine max, Glycine soja and Macroptilium atropurpureum, partially effective nodules on Desmodium canadense and Vigna unguiculata, and ineffective nodules on Amphicarpaea bracteata and Phaseolus vulgaris. Based on the data presented, we conclude that our strains represent a novel species for which the name Bradyrhizobium ottawaense sp. nov. is proposed, with OO99T ( = LMG 26739T = HAMBI 3284T) as the type strain. The DNA G+C content is 62.6 mol%.
A Review of the Forensic Implications of Pica
Authors: Byard Roger W.
Published: June 2014

Pica is characterized by the persistent eating of non‐nutritive substances over some time that is inappropriate for the maturation stage of the individual and is not culturally sanctioned. A 9‐year‐old boy with Goldenhar syndrome, significant developmental delay and pica, collapsed and died after a short history of diarrhea and vomiting. Death was due to a sigmoid volvulus resulting from filling of the distal colon with feces containing dirt, stones, and rice with evidence of ischemic intestinal necrosis. Lethal complications of pica include intestinal obstruction and perforation with peritonitis and generalized sepsis. Other findings at autopsy may include airway obstruction, heavy metal poisoning, and parasitic infestation. Presenting symptoms and signs of such complications may be subtle or masked given the nature of underlying conditions, and so careful evaluation of the medical histories of individuals with pica may be necessary to provide pertinent details of associated medical and psychiatric conditions.
Burial Patterns during Times of Armed Conflict in Cyprus in the 1960s and 1970s
Authors: Mikellide Maria
Published: June 2014

The island of Cyprus experienced two periods of intercommunal conflict during which c. 2000 individuals went missing. The Committee on Missing Persons in Cyprus began a program of exhumations in 2005, through which more than 185 burial sites pertaining to the two periods of conflict have been identified and excavated. The aim of this study was twofold: (i) to present a classification of the main types of clandestine burial and (ii) to test the hypothesis that the nature of conflict influences the mode of interment. Burials can be divided into “public burials” and “concealed burials,” based on the possible motives of those involved in the interment and then subdivided into smaller categories based on similarities in archeological context. A comparison of results from the two periods of conflict reveals that there are statistical differences (p < 0.005), which indicate that the mode of interment may reflect the nature, character, and atmosphere of conflict.
Considering external information to improve the phylogenetic comparison of microbial communities: a new approach based on constrained Double Principal Coordinates Analysis (cDPCoA)
Authors: Dray S. , Pavoine S. , Aguirre de Cárcer D.
Published: June 2014

The use of next‐generation sequencing technologies is revolutionizing microbial ecology by allowing a deep phylogenetic coverage of tens to thousands of samples simultaneously. Double Principal Coordinates Analysis (DPCoA) is a multivariate method, developed in community ecology, able to integrate a distance matrix describing differences among species (e.g. phylogenetic distances) in the analysis of a species abundance matrix. This ordination technique has been used recently to describe microbial communities taking into account phylogenetic relatedness. In this work, we extend DPCoA to integrate the information of external variables measured on communities. The constrained Double Principal Coordinates Analysis (cDPCoA) is able to enforce a priori classifications to retrieve subtle differences and (or) remove the effect of confounding factors. We describe the main principles of this new approach and demonstrate its usefulness by providing application examples based on published 16S rRNA gene data sets.
Present Geothermal Fields of the Dongpu Sag in the Bohai Bay Basin
Authors: ZUO Yinhui , QIU Nansheng , HAO Qingqing , ZHANG Yunxian , PANG Xiongqi , LI Zhongchao , GAO Xia
Published: June 2014

The Dongpu sag is located in the south of the Bohai Bay basin, China, and has abundant oil and gas reserves. To date, there has been no systematic documentation of its geothermal fields. This study measured the rock thermal conductivity of 324 cores from 47 wells, and calculated rock thermal conductivity for different formations. The geothermal gradient and terrestrial heat flow were calculated for 192 wells on basis of 892 formation‐testing data from 523 wells. The results show that the Dongpu sag is characterized by a medium‐temperature geothermal field between stable and active tectonic areas, with an average geothermal gradient of 32.0°C/km and terrestrial heat flow of 65.6 mW/m2. The geothermal fields in the Dongpu sag is significantly controlled by the Changyuan, Yellow River, and Lanliao basement faults. They developed in the Paleogene and the Dongying movement occurred at the Dongying Formation depositional period. The geothermal fields distribution has a similar characteristic to the tectonic framework of the Dongpu sag, namely two subsags, one uplift, one steep slope and one gentle slope. The oil and gas distribution is closely associated with the present geothermal fields. The work may provide constraints for reconstructing the thermal history and modeling source rock maturation evolution in the Dongpu sag.
Provenance, Tectonic Setting and Geochemistry of Ahwaz Sandstone Member (Asmari Formation, Oligo‐Miocene), Marun Oilfield, Zagros Basin, SW Iran
Authors: AVARJAM Shahram , MAHBOUBI Asadollah , MOUSSAVI‐HARAMI Reza , AMIRI‐BAKHTIAR Hassan
Published: June 2014

The Asmari Formation deposited in the Zagros foreland basin during the Oligocene‐Miocene. Lithologically, the Asmari Formation consists of limestone, dolomitic limestone, dolomite, argillaceous limestone, some anhydrite (Kalhur Member) and sandstones (Ahwaz Member). This study is based on the analysis of core samples from four subsurface sections (wells Mn‐68, Mn‐281, Mn‐292 and Mn‐312) in the Marun Oilfield in the Dezful embayment subzone in order to infer their provenance and tectonic setting of the Ahwaz Sandstone Member. Petrographical data reveal that the Ahwaz Sandstone comprises 97.5% quartz, 1.6% feldspar, and 0.9% rock fragments and all samples are classified as quartz arenites. The provenance and tectonic setting of the Ahwaz Sandstone have been assessed using integrated petrographic and geochemical studies.

Petrographic analysis reveals that mono‐ and poly‐crystalline quartz grains from metamorphic and igneous rocks of a craton interior setting were the dominant sources. Chemically, major and trace element concentrations in the rocks of the Ahwaz Sandstone indicate deposition in a passive continental margin setting. As indicated by the CIW' index (chemical index of weathering) of the Ahwaz Sandstone (average value of 82) their source area underwent “intense” recycling but “moderate to high” degree of chemical weathering. The petrography and geochemistry results are consistent with a tropical, humid climate and low‐relief highlands.
A Microscopic and Nanoscale Understanding of the Formation of Gold Geochemical Provinces
Authors: YE Rong , WANG Xueqiu , ZHANG Bimin
Published: June 2014

Gold geochemical provinces in China were delineated through stream sediment or catchment sediment sampling in this study. Each gold geochemical province delineated by a threshold value of 2.5 ng/g covers an area of thousands of kilometers. It is a dilemma that geochemists traditionally thought that gold could not migrate for a long distance in rivers or streams to form a large‐scale geochemical anomaly due to its chemical inertness and high specific density. The quantitative spectroscopic analysis and observations under a scanning electron microscope (SEM) indicate the presence of submicroscopic gold particles (<5 μm in diameter) in large quantities, and observations under a Transmission Electron Microscopy (TEM) further suggest the presence of nanoscale gold particles (several tens of nanometre in diameter) in ores, rocks, soils and stream sediments. Particularly, submicroscopic and nanoscale gold particles less than 5 μm were only found in samples having a low gold content (<10ng/g). This result shows that geochemical provinces, delineated by a threshold value of 2.5 ng/g, are formed by long‐distance transport of ultrafine gold in streams. The findings may provide direct microscopic evidence for gold migration to form geochemical provinces.