bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency domain approach for time-resolved pump-probe microscopy using intensity modulated laser diodes
Authors: Miyazaki J. , Kawasumi K. , Kobayashi T.
Published: September 2014

We present a scheme for time-resolved pump-probe microscopy using intensity modulated laser diodes. The modulation frequencies of the pump and probe beams are varied up to 500 MHz with fixed frequency detuning typically set at 15 kHz. The frequency response of the pump-probe signal is detected using a lock-in amplifier referenced at the beat frequency. This frequency domain method is capable of characterizing the nanosecond to picosecond relaxation dynamics of sample species without the use of a high speed detector or a high frequency lock-in amplifier. Furthermore, as the pump-probe signal is based on the nonlinear interaction between the two laser beams and the sample, our scheme provides better spatial resolution than the conventional diffraction-limited optical microscopes. Time-resolved pump-probe imaging of fluorescence beads and aggregates of quantum dots demonstrates that this method is useful for the microscopic analysis of optoelectronic devices. The system is implemented using compact and low-cost laser diodes, and thus has a broad range of applications in the fields of photochemistry, optical physics, and biological imaging.
Diffusion on a rugged energy landscape with spatial correlations
Authors: Banerjee Saikat , Biswas Rajib , Seki Kazuhiko , Bagchi Biman
Published: September 2014

Rugged energy landscapes find wide applications in diverse fields ranging from astrophysics to protein folding. We study the dependence of diffusion coefficient (D) of a Brownian particle on the distribution width (ɛ) of randomness in a Gaussian random landscape by simulations and theoretical analysis. We first show that the elegant expression of Zwanzig [Proc. Natl. Acad. Sci. U.S.A. 85, 2029 (1988)] for D(ɛ) can be reproduced exactly by using the Rosenfeld diffusion-entropy scaling relation. Our simulations show that Zwanzig's expression overestimates D in an uncorrelated Gaussian random lattice – differing by almost an order of magnitude at moderately high ruggedness. The disparity originates from the presence of “three-site traps” (TST) on the landscape – which are formed by the presence of deep minima flanked by high barriers on either side. Using mean first passage time formalism, we derive a general expression for the effective diffusion coefficient in the presence of TST, that quantitatively reproduces the simulation results and which reduces to Zwanzig's form only in the limit of infinite spatial correlation. We construct a continuous Gaussian field with inherent correlation to establish the effect of spatial correlation on random walk. The presence of TSTs at large ruggedness (ɛ ≫ kBT) gives rise to an apparent breakdown of ergodicity of the type often encountered in glassy liquids.
Frequency analysis of stress relaxation dynamics in model asphalts
Authors: Masoori Mohammad , Greenfield Michael L.
Published: September 2014

Asphalt is an amorphous or semi-crystalline material whose mechanical performance relies on viscoelastic responses to applied strain or stress. Chemical composition and its effect on the viscoelastic properties of model asphalts have been investigated here by computing complex modulus from molecular dynamics simulation results for two different model asphalts whose compositions each resemble the Strategic Highway Research Program AAA-1 asphalt in different ways. For a model system that contains smaller molecules, simulation results for storage and loss modulus at 443 K reach both the low and high frequency scaling limits of the Maxwell model. Results for a model system composed of larger molecules (molecular weights 300–900 g/mol) with longer branches show a quantitatively higher complex modulus that decreases significantly as temperature increases over 400–533 K. Simulation results for its loss modulus approach the low frequency scaling limit of the Maxwell model at only the highest temperature simulated. A Black plot or van Gurp-Palman plot of complex modulus vs. phase angle for the system of larger molecules suggests some overlap among results at different temperatures for less high frequencies, with an interdependence consistent with the empirical Christensen-Anderson-Marasteanu model. Both model asphalts are thermorheologically complex at very high frequencies, where they show a loss peak that appears to be independent of temperature and density.
Particle in cell simulation of low frequency instability in a current carrying plasma in the presence of negative ions
Authors: Hashemzadeh M. , Niknam A. R.
Published: September 2014

In this work, a particle in cell simulation of the low frequency Buneman instability in the presence of negative ions in a current carrying plasma is presented. Simulation results show that in the presence of negative ions, the phase space holes form earlier. Electron distribution function also confirms counter-streaming and plateau structure in this system. Energy density diagrams indicate that the saturation time depends on the velocity and mass of negative and positive ions. From growth rate diagrams, it is concluded that in the presence of heavy negative ions, the growth rate of instability decreases. In addition to the low frequency Buneman instability, it is shown that a pure ion-ion two stream instability can also be excited in the absence of electrons.
Particle-in-cell simulations of quasi-phase matched direct laser electron acceleration in density-modulated plasma waveguides
Authors: Lin M.-W. , Liu Y.-L. , Chen S.-H. , Jovanovic I.
Published: September 2014

Quasi-phase matched direct laser acceleration (DLA) of electrons can be realized with guided, radially polarized laser pulses in density-modulated plasma waveguides. A particle-in-cell model has been developed to describe the interactions among the laser field, injected electrons, and the background plasma in the DLA process. Simulations have been conducted to study the scheme in which seed electron bunches with moderate energies are injected into a plasma waveguide and the DLA is performed by use of relatively low-power (0.5–2 TW) laser pulses. Selected bunch injection delays with respect to the laser pulse, bunch lengths, and bunch transverse sizes have been studied in a series of simulations of DLA in a plasma waveguide. The results show that the injection delay is important for controlling the final transverse properties of short electron bunches, but it also affects the final energy gain. With a long injected bunch length, the enhanced ion-focusing force helps to collimate the electrons and a relatively small final emittance can be obtained. DLA efficiency is reduced when a bunch with a greater transverse size is injected; in addition, micro-bunching is clearly observed due to the focusing and defocusing of electrons by the radially directed Lorentz force. DLA should be performed with a moderate laser power to maintain favorable bunch transverse properties, while the waveguide length can be extended to obtain a higher maximum energy gain, with the commensurate increase of laser pulse duration and energy.
Hofstadter butterflies and quantized Hall conductance in quasi-one dimensional organic conductors
Authors: Ye Xiao-Shan
Published: September 2014

We explore the structure of the energy spectra of quasi-one dimensional organic conductors subjected to the field-induced spin-density-wave (FISDW) state. We show that the structure of the energy spectra can exhibit Hofstadter butterfly, which is generally believed to appear in two dimensional systems. The phenomenon of the quantized Hall conductance due to FISDW is also investigated. We find that the Hall number L, which is defined by L = σxy/(e2/h), coincides with the number described by FISDW order parameter. The sign reversal of the quantized Hall conductance is discussed theoretically.
Communication: Thermodynamics of stacking disorder in ice nuclei
Authors: Quigley D.
Published: September 2014

A simple Ising-like model for the stacking thermodynamics of ice 1 is constructed for nuclei in supercooled water, and combined with classical nucleation theory. For relative stabilities of cubic and hexagonal ice I within the range of experimental estimates, this predicts critical nuclei are stacking disordered at strong sub-cooling, consistent with recent experiments. At higher temperatures nucleation of pure hexagonal ice is recovered. Lattice-switching Monte-Carlo is applied to accurately compute the relative stability of cubic and hexagonal ice for the popular mW model of water. Results demonstrate that this model fails to adequately capture the relative energetics of the two polytypes, leading to stacking disorder at all temperatures.
On the relevance of large scale pulsed-laser deposition: Evidence of structural heterogeneities in ZnO thin films
Authors: Perrière J. , Hebert C. , Jedrecy N. , Seiler W. , Zanellato O. , Portier X. , Perez-Casero R. , Millon E. , Nistor M.
Published: September 2014

Pulsed-laser deposition is known as a well-suited method for growing thin films of oxide compounds presenting a wide range of functional properties. A limitation of this method for industrial process is the very anisotropic expansion dynamics of the plasma plume, which induces difficulties to grow on large scale films with homogeneous thickness and composition. The specific aspect of the crystalline or orientation uniformity has not been investigated, despite its important role on oxide films properties. In this work, the crystalline parameters and the texture of zinc oxide films are studied as a function of position with respect to the central axis of the plasma plume. We demonstrate the existence of large non-uniformities in the films. The stoichiometry, the lattice parameter, and the distribution of crystallites orientations drastically depend on the position with respect to the plume axis, i.e., on the oblique incidence of the ablated species. The origin of these non-uniformities, in particular, the unexpected tilted orientation of the ZnO c-axis may be attributed to the combined effects of the oblique incidence and of the ratio between oxygen and zinc fluxes reaching the surface of the growing film.
A small mode volume tunable microcavity: Development and characterization
Authors: Greuter Lukas , Starosielec Sebastian , Najer Daniel , Ludwig Arne , Duempelmann Luc , Rohner Dominik , Warburton Richard J.
Published: September 2014

We report the realization of a spatially and spectrally tunable air-gap Fabry-Pérot type microcavity of high finesse and cubic-wavelength-scale mode volume. These properties are attractive in the fields of opto-mechanics, quantum sensing, and foremost cavity quantum electrodynamics. The major design feature is a miniaturized concave mirror with atomically smooth surface and radius of curvature as low as 10 μm produced by CO2 laser ablation of fused silica. We demonstrate excellent mode-matching of a focussed laser beam to the microcavity mode and confirm from the frequencies of the resonator modes that the effective optical radius matches the physical radius. With these small radii, we demonstrate wavelength-size beam waists. We also show that the microcavity is sufficiently rigid for practical applications: in a cryostat at 4 K, the root-mean-square microcavity length fluctuations are below 5 pm.
Structural characterization and ferromagnetic properties in Ga3+doped α-Fe2O3 system prepared by coprecipitation route and vacuum annealing
Authors: Bhowmik R. N. , Vijayasri G. , Ranganathan R.
Published: September 2014

Structural and magnetic properties of α-Fe2-xGaxO3 system in the range of low Ga content (x = 0.28–0.60) have been discussed in the present work. The samples with nanometer grain size have been prepared by coprecipitation of the metal hydroxides at high alkaline medium. The as prepared samples have been annealed at 800 °C under vacuum. Synchrotron X-ray diffraction pattern of the samples has been used to confirm rhombohedral structure with space group R3¯C, along with extra phase less than 2% of the rhombohedral phase. Raman active phonon modes are consistent with the spectrum of rhombohedral structure in α-Fe2O3. Raman spectra revealed structural disorder at microscopic level due to doping effect. The samples of α-Fe2-xGaxO3 system exhibited ferromagnetic properties and magnetization showed increasing trend with the increase of Ga content. Low temperature x-ray diffraction pattern and magnetization have been studied for the sample with x = 0.6 to test the correlation between structure and ferromagnetic parameters.
In situ infrared spectroscopy study of the interface self-cleaning during the atomic layer deposition of HfO2 on GaAs(100) surfaces
Authors: Ye Liwang , Gougousi Theodosia
Published: September 2014

In situ attenuated total reflectance Fourier transform infrared spectroscopy was utilized to study the interface evolution during the atomic layer deposition (ALD) of HfO2 on GaAs surfaces using of tetrakis (dimethylamino) hafnium and H2O. The experiments were performed on chemical oxide and hydrogen fluoride etched GaAs(100) starting surfaces. For the deposition of HfO2 on chemical oxide GaAs surfaces at 275 °C, which corresponds to the optimal ALD process temperature, continuous arsenic oxide removal was observed for the first 20 ALD cycles. The oxide removal was more pronounced at the initial 1-2 cycles but nonetheless persisted, at a reduced rate, up to the 20th cycle. The substrate temperature was confirmed to affect the arsenic oxide removal; the rate was significant at temperatures above 250 °C while negligible below 200 °C.
Wavelength-tunable infrared metamaterial by tailoring magnetic resonance condition with VO2 phase transition
Authors: Wang Hao , Yang Yue , Wang Liping
Published: September 2014

In this work, we report the design of a wavelength-tunable infrared metamaterial by tailoring magnetic resonance condition with the phase transition of vanadium dioxide (VO2). Numerical simulation based on the finite-difference time-domain method shows a broad absorption peak at the wavelength of 10.9 μm when VO2 is a metal, but it shifts to 15.1 μm when VO2 changes to dielectric phase below its phase transition temperature of 68 °C. The large tunability of 38.5% in the resonance wavelength stems from the different excitation conditions of magnetic resonance mediated by plasmon in metallic VO2 but optical phonons in dielectric VO2. The physical mechanism is elucidated with the aid of electromagnetic field distribution at the resonance wavelengths. A hybrid magnetic resonance mode due to the plasmon-phonon coupling is also discussed. The results here would be beneficial for active control of thermal radiation in novel electronic, optical, and thermal devices.
Quantum size effect on Shubnikov-de Haas oscillations in 100 nm diameter single-crystalline bismuth nanowire
Authors: Kim Jeongmin , Kim Dohun , Chang Taehoo , Lee Wooyoung
Published: September 2014

Quantum size effect (QSE) in Bi nanowire is theoretically predicted to decrease band overlap energy resulting in semimetal-to-semiconductor transition. However, this effect has been rarely demonstrated on transport properties because of carrier-surface scattering and charge carriers induced from surface states of Bi. We report QSE on Shubnikov-de Haas (SdH) oscillations in a single-crystalline Bi nanowire with a diameter of 100 nm. The variation of intrinsic properties estimated using SdH oscillations indicates that the subband energy shift due to QSE. The enhanced effective mass of the electrons is consistent with the theoretical prediction pertaining to strong electron-hole coupling of Bi.
Long term PM2.5 trends in the Australian industrial city of Newcastle: a 15-year study from 1998 to 2013
Authors: Stelcer Eduard , Cohen David D. , Atanacio Armand J.
Published: September 2014

Environmental context Long-term exposure to fine particle air pollution has significant implications for human health. At a mixed urban–industrial site in Newcastle, Australia, we identified contributions from individual industrial aerosol sources in addition to the more common aerosol sources such as soil, sea and smoke. These results are significant for the assessment and management of fine particulate air pollution in the Newcastle air shed. Abstract A long-term, large dataset approach combining standard accelerator-based ion beam analysis (IBA) techniques with positive matrix factorisation (PMF) analysis to determine the sources and trends of fine particle pollution in the Newcastle NSW, Australia is discussed. Over 1500 samples of particle matter with aerodynamic diameter less than 2.5µm (PM2.5) were collected between February 1998 and December 2013 and analysed using IBA techniques to obtain the concentration of 22 different elements from hydrogen to lead. The PM2.5 15-year average mass at the sampling site was 8.11µgm–3. Statistical PMF analysis was applied to this large dataset to quantitatively determine nine source fingerprints; soil, secondary sulfate, sea, smoke, industrial processes (specifically related to calcium, manganese and iron) and two different automobile sources. Significant step-like reductions of 98, 79 and 69%, over and above regular seasonal variations, were clearly observed in the industrial-Mn, industrial-Fe and automobile sources during this time period. These trends showed excellent correlation with the cessation of large industrial operations in the local area and clearly demonstrate the advantage of long-term aerosol analysis for monitoring and managing fine particle air pollution sources on a local scale.
Population structure and biology of shortfin mako, Isurus oxyrinchus, in the south-west Indian Ocean
Authors: Groeneveld J. C. , Cliff G. , Dudley S. F. J. , Foulis A. J. , Santos J. , Wintner S. P.
Published: September 2014

The population structure, reproductive biology, age and growth, and diet of shortfin makos caught by pelagic longliners (2005–10) and bather protection nets (1978–2010) in the south-west Indian Ocean were investigated. The mean fork length (FL) of makos measured by observers on longliners targeting tuna, swordfish and sharks was similar, and decreased from east to west, with the smallest individuals occurring near the Agulhas Bank edge, June to November. Nearly all makos caught by longliners were immature, with equal sex ratio. Makos caught by bather protection nets were significantly larger, males were more frequent, and 93% of males and 55% of females were mature. Age was assessed from band counts of sectioned vertebrae, and a von Bertalanffy growth model fitted to sex-pooled length-at-age data predicted a birth size (L0) of 90 cm, maximum FL (L∞) of 285 cm and growth coefficient (k) of 0.113 y–1. Males matured at 190 cm FL, aged 7 years, and females at 250 cm, aged 15 years. Litter sizes ranged from nine to 14 pups, and the presence of gravid females in bather protection nets suggested that some pupping occurred in shelf waters. Teleosts (mainly Trachurus capensis) occurred in 84% of stomachs collected on longliners, whereas elasmobranchs (63.5%) were most common in samples collected from bather protection nets, followed by teleosts (43.1%) and cephalopods (36.5%). Larger prey size may be a factor that attracts large makos to coastal waters.
Carbon projects and Indigenous land in northern Australia
Authors: Dore Jeremy , Michael Christine , Russell-Smith Jeremy , Tehan Maureen , Caripis Lisa
Published: September 2014

Land activities contribute ~18% of total greenhouse gas emissions produced in Australia. To help reduce these emissions, the Carbon Farming Initiative (CFI) was implemented in 2011 to encourage land projects, which reduce the production of greenhouse gases and/or sequester carbon in the land. Prospective projects include savanna fire management and rangelands management, which have high relevance in northern Australia where Indigenous landholding is strong. This paper explores the land-tenure requirements necessary for these kinds of carbon projects to be approved by the Clean Energy Regulator. It provides an introduction to the CFI before discussing the land tenure requirements in the states of Queensland, the Northern Territory and Western Australia with respect to both emissions reduction and carbon sequestration projects. Potential issues with the current framework are highlighted, especially in relation to native title.
Opportunities for fire and carbon on pastoral properties in the savanna rangelands: perspectives from the Indigenous Land Corporation and the Northern Territory Cattlemen's Association
Authors: Walton Nerissa , Smith Hilary , Bowen Luke , Mitchell Paul , Pethybridge Emma , Hayes Tracey , O'Ryan Michael
Published: September 2014

Understanding both the carbon dynamics within Australia’s northern savannas and the opportunities presented through diversification into carbon markets is of relevance to pastoral land managers both in Australia and globally. The Indigenous Land Corporation (ILC), through its role in assisting Indigenous people to acquire and manage land for cultural, social, environmental and economic benefits, has operated in the carbon market and is keen to continue working with its partners to explore the opportunities to develop and broaden this further. The Northern Territory Cattlemen’s Association, as the major industry body for the pastoral industry in the Northern Territory, has been actively involved in assessing the opportunities which may be presented through greenhouse gas abatement where these are compatible with sound resource and economic management. In recent years, Australian governments have considered and developed diversified carbon abatement opportunities for farmers, particularly through the Carbon Farming Initiative (CFI). Australian Carbon Credit Units generated through the CFI can contribute to meeting Australia’s commitments under international agreements to reduce greenhouse gas emissions. The opportunity for economic diversification into carbon farming on marginal land where the primary land use is pastoralism is of particular interest, particularly where it can lead to strengthened economic returns, jobs and other benefits for Indigenous people. Lessons learnt from the ILC’s Fish River Fire Project demonstrate the potential, but also emphasise the need for further research into the practicalities of introducing carbon projects into predominantly pastoral landscapes in Australia and internationally. It is suggested that several issues require further assessment by pastoralists who may be considering engaging in the CFI or other carbon markets.
How much soil organic carbon sequestration is due to conservation agriculture reducing soil erosion?
Authors: Li Yong , Yu Hanqing , Chappell Adrian , Zhou Na , Funk Roger
Published: September 2014

Soil organic carbon (SOC) redistribution by soil erosion is fundamental to the C cycle and is a key component of global soil C accounting. Widespread conversion of cropland to forest and grassland and the adoption of conservation agriculture (minimum-till and no-till practices) worldwide and particularly in China since 2000, may have reduced wind erosion and increased SOC storage and ‘avoided’ CO2 emission. However, few SOC sequestration studies have separated changes in SOC stock caused by changes in land-use and management activity from net SOC redistribution due to reduced SOC erosion and SOC dust accumulation, particularly from individual or short-term (months) wind erosion events. We used measurements of SOC and the short-lived natural radionuclide beryllium-7 (7Be, half-life 53.3 days) to estimate net SOC redistribution for changes in several land-use and management practices in Fengning County in North China. Compared with conventional tillage (CT), conservation grassland (CG) and minimum tillage (CL) showed enhanced SOC stocks (0–245 mm depth) of ~0.8 ± 0.03 and 2.0 ± 0.06 t C ha–1 year–1 as a consequence of their land-use conversion for 5 and 3 years, respectively. However, SOC erosion on CG (0.46 ± 0.04 t C ha–1 year–1) and CL (0.52 ± 0.04 t C ha–1 year–1) plots was 54% and 47%, respectively, less than on CT (0.99 ± 0.11 t C ha–1 year–1). Net C sequestration (0–245 mm), considering SOC redistribution for CG (0.27 ± 0.12 t C ha–1 year–1; 5 years) and CL (1.53 ± 0.13 t C ha–1 year–1; 3 years), revealed an overestimate of 196% and 31% without considering SOC redistribution (CG, 0.8 ± 0.03 t C ha–1 year–1; CL, 2.0 ± 0.06 t C ha–1 year–1), respectively, relative to CT. Reduced SOC erosion and/or SOC dust accumulation by vegetation–crop cover must be included when considering SOC sequestration induced by changes in land use and management.
Functional polysaccharides from Grifola frondosa aqueous extract inhibit atopic dermatitis-like skin lesions in NC/Nga mice
Authors: Park Hyeon Soo , Hwang Yong Hyeon , Kim Mun Ki , Hong Gyeong Eun , Lee Ho Jeong , Nagappan Arulkumar , Yumnam Silvia , Kim Eun Hee , Heo Jeong Doo , Lee Sang Joon , Won Chung Kil , Kim Gon Sup
Published: September 2014

Grifola frondosa (GF), distributed widely in far east Asia including Korea, is popularly used as traditional medicines and health supplementary foods, especially for enhancing the immune functions of the body. To extend the application of GF polysaccharides (GFP) for atopic dermatitis (AD), we investigated the effects of GFP on the 2,4-dinitrochlorobenzene-induced AD-like skin lesion in NC/Nga mice. GFP treatment significantly reduced the dorsa skin dermatitis score and combination treatment with GFP, and dexamethasone has a synergistic effect in AD-like skin lesion by reduced Serum IgE, mast cells infiltration, and cytokines expression. These results indicate that GFP suppressed the AD-like skin lesions by controlling the Th-1/Th-2-type cytokines in NC/Nga mice. These findings strongly suggest that GFP can be useful for AD patients as a novel therapeutic agent and might be used for corticosteroids replacement or supplement agent.
Aerobic, resistance and combined exercise training on arterial stiffness in normotensive and hypertensive adults: A review
Authors: Li Yanlei , Hanssen Henner , Cordes Mareike , Rossmeissl Anja , Endes Simon , Schmidt‐Trucksäss Arno
Published: September 2014

Exercise training has different effects on arterial stiffness according to training modalities. The optimal exercise modality for improvement of arterial function in normotensive and hypertensive individuals has not been well established. In this review, we aim to evaluate the effects of aerobic, resistance and combined aerobic and resistance training on arterial stiffness in individuals with and without hypertension. We systematically searched the Pubmed and Web of Science database from 1985 until December 2013 for relevant randomised controlled trials (RCTs). The data were extracted by one investigator and checked by a second investigator. The training effects on arterial stiffness were estimated using weighted mean differences of the relative changes (%) with 95% confidence intervals (CIs). We finally reviewed the results from 17 RCTs. The available evidence indicates that aerobic exercise tends to have a beneficial effect on arterial stiffness in normotensive and hypertensive patients, but does not affect arterial stiffness in patients with isolated systolic hypertension. Resistance exercise has differing effects on arterial stiffness depending on type and intensity. Vigorous resistance training is associated with an increase in arterial stiffness. There seem to be no unfavourable effects on arterial stiffness if the training is of low intensity, in a slow eccentric manner or with lower limb in healthy individuals. Combined training has neutral or even a beneficial effect on arterial stiffness. In conclusion, our review shows that exercise training has varying effects on arterial stiffness depending on the exercise modalities.
Comparability of accelerometer‐ and IPAQ‐derived physical activity and sedentary time in South Asian women: A cross‐sectional study
Authors: Curry Whitney Babakus , Thompson Janice L.
Published: September 2014

There is limited research documenting objectively measured physical activity (PA) and sedentary time (ST) in South Asian (SA) women, with no published evidence of the validity of self‐report methods for assessment of PA/ST in SA. The purpose of this study was to compare accelerometer‐ and International Physical Activity Questionnaire (IPAQ)‐derived PA/ST among SA women in the United Kingdom (UK) via a mixed‐methods approach. One hundred and forty SA women wore an accelerometer for seven consecutive days; a sub‐sample (n = 50) completed the IPAQ‐Short Form (IPAQ‐SF) and a brief structured interview. Accelerometer‐derived metabolic equivalent (MET) minutes per week (min/wk) moderate‐to‐vigorous physical activity (MVPA) (mean ± SD) for the full sample was 793.94 (±519.44) and mean accelerometer‐derived ST wk was 530.20 (±81.76). IPAQ‐SF‐derived MVPA (MET min/wk) was 636.80 (±2113.56) and mean ST wk was 315.31 (±266.98). Pearson correlations were not significant between accelerometer‐ and IPAQ‐SF‐assessed MVPA (r = −.119, p =. 579) and ST (r = −.140, p =. 229). Major themes synthesised from interviews included inability to recall sitting time and limited general knowledge of real‐life examples of MVPA. These results suggest that the IPAQ‐SF may not accurately measure PA/ST in the UK SA women. These findings are supported by qualitative evidence indicating several issues with interpretation and recall of PA/ST as assessed via this questionnaire.
Minimal free resolutions of the 𝐺-parking function ideal and the toppling ideal
Authors: Manjunath Madhusudan , Schreyer Frank-Olaf , Wilmes John
Published: September 2014

The

G
G

-parking function ideal

M
G

M_G

of a directed multigraph

G
G

is a monomial ideal which encodes some of the combinatorial information of

G
G

. It is an initial ideal of the toppling ideal

I
G

I_G

, a lattice ideal intimately related to the chip-firing game on a graph. Both ideals were first studied by Cori, Rossin, and Salvy. A minimal free resolution for

M
G

M_G

was given by Postnikov and Shapiro in the case when

G
G

is saturated, i.e., whenever there is at least one edge

(
u
,
v
)

(u,v)

for every ordered pair of distinct vertices

u
u

and

v
v

. They also raised the problem of an explicit description of the minimal free resolution in the general case. In this paper, we give a minimal free resolution of

M
G

M_G

for any undirected multigraph

G
G

, as well as for a family of related ideals including the toppling ideal

I
G

I_G

. This settles a conjecture of Manjunath and Sturmfels, as well as a conjecture of Perkinson and Wilmes.
Fewer eggs from larger size limits: counterintuitive outcomes in a spatially heterogeneous fishery
Authors: Gardner Caleb , Hartmann Klaas , Punt André E. , Hoshino Eriko
Published: September 2014

The legal minimum length (LML) of female Southern Rock Lobster (Jasus edwardsii) was reduced in the Tasmanian fishery in 1966 for higher sustainable catches. Originally, the LML was to be reduced in slow growth southern areas only; however, the change was implemented across the entire fishery due to lobbying by commercial fishers. The lower LML has been controversial ever since, including during recent years when low recruitment resulted in a lower total allowable catch (TAC). Fishers argued that this could have been prevented with a higher female LML across the jurisdiction. A length- and sex-based bioeconomic model was used to examine probable outcomes of the larger statewide LML. This model showed that management of egg production would be poorly served by raising the statewide LML because of spatial patterns in the stock and fishery. Catch would be displaced from areas where egg production was already high and into the most depleted areas thus reducing production in areas of greatest concern. Spatial variation in biological parameters can have a profound effect on outcomes of management perceived to be conservative, possibly leading to negative impacts. This risk exists wherever catch is displaced, such as with Marine Protected Areas, spatial TACs and gear restrictions.
Lamiophlomis rotata, an Orally Available Tibetan Herbal Painkiller, Specifically Reduces Pain Hypersensitivity States through the Activation of Spinal Glucagon-like Peptide-1 Receptors
Authors: Zhu Bin , Gong Nian , Fan Hui , Peng Chong-Sheng , Ding Xiu-Juan , Jiang Yi , Wang Yong-Xiang
Published: September 2014

Background:

Lamiophlomis rotata is an orally available Tibetan herb prescribed for the management of pain, with shanzhiside methylester (SM) and 8-O-acetyl-SM as quality control ingredients. This study aimed to evaluate the antinociceptive properties of L. rotata, determine whether SM and 8-O-acetyl-SM are principle effective ingredients, and explore whether L. rotata produces antinociception through activation of spinal glucagon-like peptide-1 receptors (GLP-1Rs).

Methods:

Formalin test, neuropathic pain, and bone cancer pain models were used, and the animal sample size was 5 to 6 in each group. Hydrogen peroxide–induced oxidative damage was also assayed.

Results:

The L. rotata aqueous extract blocked formalin-induced tonic hyperalgesia and peripheral nerve injury– and bone cancer–induced mechanical allodynia by 50 to 80%, with half-effective doses of 130 to 250 mg/kg, close to the human dosage. The herb was not effective in alleviating acute nociceptive pain. A 7-day gavage with L. rotata aqueous extract did not lead to antiallodynic tolerance. Total iridoid glycosides, rather than total flavonoids, were identified by the activity-tracking method as effective ingredients for antihyperalgesia, whereas both SM and 8-O-acetyl-SM were principal components. Further demonstrations using the GLP-1R antagonist and gene silencer against GLP-1R at both the spinal and the cellular levels indicated that L. rotata inhibited pain hyperactivity by activation of spinal GLP-1Rs, and SM and 8-O-acetyl-SM appeared to be orthosteric, reversible, and fully intrinsic agonists of both rat and human GLP-1Rs.

Conclusions:

Results support the notion that the activation of spinal GLP-1Rs leads to specific antinociception in pain hypersensitivity and further suggest that GLP-1R is a human-validated target molecule for the treatment of chronic pain.
Outcomes of Aortic Valve and Concomitant Ascending Aorta Replacement Performed via a Minimally Invasive Right Thoracotomy Approach
Authors: LaPietra Angelo , Santana Orlando , Pineda Andrés M. , Mihos Christos G. , Lamelas Joseph
Published: September 2014

Objective

Replacement of the aortic valve with concomitant replacement of the ascending aorta performed via a minimally invasive right anterior thoracotomy approach has not been reported. We evaluated the feasibility and safety of this procedure.

Methods

We retrospectively reviewed all minimally invasive aortic valve replacements (AVRs) with concomitant replacement of the ascending aorta performed at our institution between January 1, 2012, and December 30, 2012. The operative times, intensive care unit and hospital lengths of stay, postoperative outcomes, as well as mortality were analyzed.

Results

A total of 20 consecutive patients who underwent minimally invasive AVR with concomitant replacement of the ascending aorta were identified. There were 16 men (80%), with a mean (SD) age of 61 (13) years. The mean (SD) left ventricular ejection fraction was 58% (8%). The aortic valve was bicuspid in 18 patients (80%), with 14 (70%) being stenotic. The median aortic cross-clamp and cardiopulmonary bypass times were 163 [interquartile range (IQR), 141–170] minutes and 291 (IQR, 177–215) minutes, respectively. Hypothermic circulatory arrest was required in 19 patients (95%), with a median hypothermic circulatory arrest time of 35 (IQR, 33–39.5) minutes. The median intensive care unit and hospital lengths of stay were 24 (IQR, 23–41) hours and 5 (IQR, 4–6) days, respectively. There were no strokes, reoperations for bleeding, or conversions to sternotomy. The 30-day mortality was zero.

Conclusions

Minimally invasive AVR with concomitant replacement of the ascending aorta, via a right anterior thoracotomy approach, can be performed with low morbidity and mortality.
Synergistic interaction between UVB radiation and temperature increases susceptibility to parasitic infection in a fish
Authors: Cramp Rebecca L. , Reid Stefanie , Seebacher Frank , Franklin Craig E.
Published: September 2014

Levels of UVB radiation (UVB) and mean temperatures have increased substantially over recent decades in many regions of the world. Both stressors independently can compromise immune function, disease resistance and fitness in fish. The impact of UVB can also be exacerbated by interactions with environmental temperatures. In this paper, we test the hypothesis that UVB and temperature act synergistically to influence patterns of energy consumption and susceptibility to disease. We exposed mosquitofish,
Gambusia holbrooki
, to a factorial design of low and high UVB levels and low (18°C) and high (25°C) temperatures. The combination of high UVB and high temperature interacted synergistically to suppress metabolism and exacerbate infection intensity by the fish pathogen whitespot (
Ichtyhophthirius multifiliis
). Given the rapid changes in the thermal environment globally, the interaction between UVB and temperatures on energy use and disease resistance could pose significant problems for aquatic animal health in the context of both pre-existing and emerging diseases.
Statistical analysis and simulation of random shocks in stochastic Burgers equation
Authors: Cho Heyrim , Venturi Daniele , Karniadakis George E
Published: September 2014

We study the statistical properties of random shock waves in stochastic Burgers equation subject to random space–time perturbations and random initial conditions. By using the response–excitation probability density function (PDF) method and the Mori–Zwanzig (MZ) formulation of irreversible statistical mechanics, we derive exact reduced-order equations for the one-point and two-point PDFs of the solution field. In particular, we compute the statistical properties of random shock waves in the inviscid limit by using an adaptive (shock-capturing) discontinuous Galerkin method in both physical and probability spaces. We consider stochastic flows generated by high-dimensional random initial conditions and random additive forcing terms, yielding multiple interacting shock waves collapsing into clusters and settling down to a similarity state. We also address the question of how random shock waves in space and time manifest themselves in probability space. The proposed new mathematical framework can be applied to different conservation laws, potentially leading to new insights into high-dimensional stochastic dynamical systems and more efficient computational algorithms.
On acoustic and electric Faraday cages
Authors: Martin P. A.
Published: September 2014

Two-dimensional problems involving many identical small circles are considered; the circles are the cross sections of parallel wires, modelling a cage or a grating. Both electrostatic and acoustic fields are considered. The main emphasis is on periodic configurations of
N
circles distributed evenly around a large circle (a ring). Foldy's theory is used for acoustic problems and then adapted for electrostatic problems. In both cases, circulant matrices are encountered: the fields can be calculated explicitly. Then, the limit

N
→
∞

is studied. A connection between the
N
-circle problem and the limiting problem (fields exterior to the ring) is established, using known results on the convergence of a defective form of the trapezoidal rule, defective in that endpoint contributions are ignored, because the integrand has logarithmic singularities at those points. This shows that the solution of the limiting problem is approached very slowly, as

N

−
1

log

N

as

N
→
∞

.
The path of least resistance: aggressive or moderate treatment?
Authors: Kouyos Roger D. , Metcalf C. Jessica E. , Birger Ruthie , Klein Eili Y. , Abel zur Wiesch Pia , Ankomah Peter , Arinaminpathy Nimalan , Bogich Tiffany L. , Bonhoeffer Sebastian , Brower Charles , Chi-Johnston Geoffrey , Cohen Ted , Day Troy , Greenhouse Bryan , Huijben Silvie , Metlay Joshua , Mideo Nicole , Pollitt Laura C. , Read Andrew F. , Smith David L. , Standley Claire , Wale Nina , Grenfell Bryan
Published: September 2014

The evolution of resistance to antimicrobial chemotherapy is a major and growing cause of human mortality and morbidity. Comparatively little attention has been paid to how different patient treatment strategies shape the evolution of resistance. In particular, it is not clear whether treating individual patients aggressively with high drug dosages and long treatment durations, or moderately with low dosages and short durations can better prevent the evolution and spread of drug resistance. Here, we summarize the very limited available empirical evidence across different pathogens and provide a conceptual framework describing the information required to effectively manage drug pressure to minimize resistance evolution.
Transgenerational interactions involving parental age and immune status affect female reproductive success inDrosophila melanogaster
Authors: Nystrand M. , Dowling D. K.
Published: September 2014

It is well established that the parental phenotype can influence offspring phenotypic expression, independent of the effects of the offspring's own genotype. Nonetheless, the evolutionary implications of such parental effects remain unclear, partly because previous studies have generally overlooked the potential for interactions between parental sources of non-genetic variance to influence patterns of offspring phenotypic expression. We tested for such interactions, subjecting male and femaleDrosophila melanogasterof two different age classes to an immune activation challenge or a control treatment. Flies were then crossed in all age and immune status combinations, and the reproductive success of their immune- and control-treated daughters measured. We found that daughters produced by two younger parents exhibited reduced reproductive success relative to those of other parental age combinations. Furthermore, immune-challenged daughters exhibited higher reproductive success when produced by immune-challenged relative to control-treated mothers, a pattern consistent with transgenerational immune priming. Finally, a complex interplay between paternal age and parental immune statuses influenced daughter's reproductive success. These findings demonstrate the dynamic nature of age- and immune-mediated parental effects, traceable to both parents, and regulated by interactions between parents and between parents and offspring.
Turnover and accumulation of genetic diversity across large time-scale cycles of isolation and connection of populations
Authors: Alcala Nicolas , Vuilleumier Séverine
Published: September 2014

Major climatic and geological events but also population history (secondary contacts) have generated cycles of population isolation and connection of long and short periods. Recent empirical and theoretical studies suggest that fast evolutionary processes might be triggered by such events, as commonly illustrated in ecology by the adaptive radiation of cichlid fishes (isolation and reconnection of lakes and watersheds) and in epidemiology by the fast adaptation of the influenza virus (isolation and reconnection in hosts). We test whether cyclic population isolation and connection provide the raw material (standing genetic variation) for species evolution and diversification. Our analytical results demonstrate that population isolation and connection can provide, to populations, a high excess of genetic diversity compared with what is expected at equilibrium. This excess is either cyclic (high allele turnover) or cumulates with time depending on the duration of the isolation and the connection periods and the mutation rate. We show that diversification rates of animal clades are associated with specific periods of climatic cycles in the Quaternary. We finally discuss the importance of our results for macroevolutionary patterns and for the inference of population history from genomic data.
Maternal body condition influences magnitude of anti-predator response in offspring
Authors: Bennett Amanda M. , Murray Dennis L.
Published: September 2014

Organisms exhibit plasticity in response to their environment, but there is large variation even within populations in the expression and magnitude of response. Maternal influence alters offspring survival through size advantages in growth and development. However, the relationship between maternal influence and variation in plasticity in response to predation risk is unknown. We hypothesized that variation in the magnitude of plastic responses between families is at least partly due to maternal provisioning and examined the relationship between maternal condition, egg provisioning and magnitude of plastic response to perceived predation risk (by dragonfly larvae:Aeshnaspp.) in northern leopard frogs (Lithobates pipiens). Females in better body condition tended to lay more (clutch size) larger (egg diameter) eggs. Tadpoles responded to predation risk by increasing relative tail depth (morphology) and decreasing activity (behaviour). We found a positive relationship between morphological effect size and maternal condition, but no relationship between behavioural effect size and maternal condition. These novel findings suggest that limitations imposed by maternal condition can constrain phenotypic variation, ultimately influencing the capacity of populations to respond to environmental change.
Assessing the Metabolic Impact of Nitrogen Availability Using a Compartmentalized Maize Leaf Genome-Scale Model
Authors: Simons Margaret , Saha Rajib , Amiour Nardjis , Kumar Akhil , Guillard Lenaïg , Clément Gilles , Miquel Martine , Li Zhenni , Mouille Gregory , Lea Peter J. , Hirel Bertrand , Maranas Costas D.
Published: September 2014

Maize (Zea mays) is an important C4 plant due to its widespread use as a cereal and energy crop. A second-generation genome-scale metabolic model for the maize leaf was created to capture C4 carbon fixation and investigate nitrogen (N) assimilation by modeling the interactions between the bundle sheath and mesophyll cells. The model contains gene-protein-reaction relationships, elemental and charge-balanced reactions, and incorporates experimental evidence pertaining to the biomass composition, compartmentalization, and flux constraints. Condition-specific biomass descriptions were introduced that account for amino acids, fatty acids, soluble sugars, proteins, chlorophyll, lignocellulose, and nucleic acids as experimentally measured biomass constituents. Compartmentalization of the model is based on proteomic/transcriptomic data and literature evidence. With the incorporation of information from the MetaCrop and MaizeCyc databases, this updated model spans 5,824 genes, 8,525 reactions, and 9,153 metabolites, an increase of approximately 4 times the size of the earlier iRS1563 model. Transcriptomic and proteomic data have also been used to introduce regulatory constraints in the model to simulate an N-limited condition and mutants deficient in glutamine synthetase, gln1-3 and gln1-4. Model-predicted results achieved 90% accuracy when comparing the wild type grown under an N-complete condition with the wild type grown under an N-deficient condition.