bluuebunny/crossref_metadata_2025 huggingface dataset:
HOW DOES MONETARY POLICY CHANGE? EVIDENCE ON INFLATION-TARGETING COUNTRIES
Authors: Baxa Jaromír , Horváth Roman , Vašíček Bořek
Published: March 2013

We examine the evolution of monetary policy rules in a group of inflation-targeting countries (Australia, Canada, New Zealand, Sweden, and the United Kingdom), applying a moment-based estimator in a time-varying parameter model with endogenous regressors. From this novel flexible framework, our main findings are threefold. First, monetary policy rules change gradually, pointing to the importance of applying a time-varying estimation framework. Second, the interest-rate smoothing parameter is much lower than typically reported by previous time-invariant estimates of policy rules. External factors matter for all countries, although the importance of the exchange rate diminishes after the adoption of inflation targeting. Third, the response of interest rates to inflation is particularly strong during periods when central bankers want to break a record of high inflation, such as in the United Kingdom or Australia at the beginning of the 1980s. Contrary to common perceptions, the response becomes less aggressive after the adoption of inflation targeting, suggesting a positive anchoring effect of this regime on inflation expectations. This result is supported by our finding that inflation persistence typically decreased after the adoption of inflation targeting.
The folate status of reproductive-aged women in a randomised trial of a folate-fortified oral contraceptive: dietary and blood assessments
Authors: Castaño Paula M , Aydemir Aida , Sampson-Landers Carole , Lynen Richard
Published: March 2013

Objective

To assess the folate status of US women in a study of a folate-fortified oral contraceptive (OC) using the Short Folate Food Frequency Questionnaire and plasma and red blood cell (RBC) folate samples.

Design

Sub-analysis from a multi-centre, randomised, double-blind, controlled contraceptive trial with assessments at baseline and 6 months. We calculated dietary folate equivalents (DFE) consumed and the proportion of participants meeting folate adequacy benchmarks.

Setting

Eight centres in the USA.

Subjects

Healthy women aged 18–40 years requesting contraception with no contraindications for OC use.

Results

Overall, 385 participants were randomised to either a novel folate-fortified OC or a marketed OC. The 262 (68 %) participants compliant with the protocol were included in the analysis set. Baseline daily DFE consumption was 529·8 (sd 342·1) μg and similar in both groups. At follow-up, the fortified OC group had higher intake than the conventional OC group (1225·9 (sd 346·2) μg compared with 500·6 (sd 361·2) μg). Mean plasma folate level increased from 44·5 (sd 17·2) to 55·8 (sd 21·1) nmol/l. Mean RBC folate level increased from 996·7 (sd 369·8) to 1311·9 (sd 436·0) nmol/l. The proportion meeting selected folate adequacy benchmarks increased in the fortified OC group (P < 0·001).

Conclusions

Lack of adequate folate intake in reproductive-aged women from dietary sources or supplements alone suggests the need for novel approaches. Use of folate-fortified OC ensures adequate folate levels and meeting of folate benchmarks.
Composing Individuals: Ethnographic Reflections on Success and Prestige in the British New Music Network
Authors: MALCOMSON HETTIE
Published: March 2013

In contrast to established musicians, lesser-known composers have received scant attention in art music scholarship. This article, based on an ethnographic study, considers how a group of British composers construed ideas of success and prestige, which I analyse in terms of anthropological writings on exchange, Bourdieusian symbolic economies, and Foucauldian notions of disciplinary power. Prestige was ascribed to composers who created ‘interesting’ music, a category that eclipsed novelty as an aim. Individuality, enacted within a context of individualism, was key to assessing whether music was interesting. This individuality had to be tempered, structured, and embedded in the social norms of this and related ‘art worlds’. The article examines the social processes involved in creating this individuality, musical personality, and music considered interesting.
Nitrogen mineralisation dynamics of meat bone meal and cattle manure as affected by the application of softwood chip biochar in soil
Authors: Tammeorg Priit , Brandstaka Tero , Simojoki Asko , Helenius Juha
Published: March 2013

We studied the impact of added biochar on the N mineralisation dynamics of two organic fertilisers by incubating loamy sand soil for 133 days in controlled conditions. Biochar made from softwood chips was added to soil at 0, 4·6, 9·1 and 13·6 g kg–1soil dry matter (DM) either alone, or in combination with meat bone meal (MBM) and composted cattle manure (CCM) fertilisers. Soil mineral N concentration was determined on days 0, 14, 28, 56, 84 and 133. Net N mineralisation in the MBM treatment was much larger than in the CCM or the unfertilised treatments. Constant soil moisture during the incubation provided suitable aerobic soil conditions for nitrification: after day 14, soil mineral N was dominated by nitrate in all treatments. Biochar additions decreased the mineral N concentrations in all treatments, probably because of immobilisation by microbes. In unfertilised soil, the immobilisation by biochar increased steadily with application rate and time, but in the MBM and CCM treatments, it started to decrease or level off after two months, possibly due to the turnover of microbial biomass. The main biochar-induced impacts on soil N mineralisation dynamics could be modelled by using standard and confined exponential models.
Die Evaluation von Therapiesitzungen durch Patienten und Therapeuten
Authors: Hartmann Armin , Leonhart Rainer , Hermann Sabine , Joos Andreas , Stiles William B. , Almut Zeeck
Published: March 2013

Das Session Evaluation Questionnaire (SEQ) wurde ins Deutsche übersetzt. Es erfasst die unmittelbaren Auswirkungen einer Therapiesitzung in je eigener Version für Patienten und Therapeuten. Primäres Ziel der Untersuchung war die Replikation der Faktorstruktur, sekundäres Ziel die Bestimmung der Übereinstimmung der Patienten- und Therapeutensicht. Die Stichprobe umfasst 1164 Therapiesitzungen aus 98 Therapien (26 Therapeuten) zu denen aus Patienten- und Therapeutensicht das SEQ erhoben wurde. Für beide Perspektiven wurde mittels Konfirmatorischer Mehrebenen Faktoranalyse die Anpassungsgüte der amerikanischen Faktorlösung überprüft. Die Faktoren Tiefe, Fluss & Positivität des SEQ lassen sich in der deutschen Version replizieren. Der vierte Faktor „Aufregung” erweist sich für die deutsche Version des SEQ als nicht reliabel. Patienten- und Therapeutensicht einer Stunde sind wenig konvergent. Der SEQ-D steht als deutschsprachiges, international vergleichbares und therapie-schulenübergreifendes Instrument für Psychotherapieprozessforschungsfragen zur Verfügung.
Metasignatures Identify Two Major Subtypes of Breast Cancer
Authors: Duan Q , Kou Y , Clark NR , Gordonov S , Ma'ayan A
Published: March 2013

Genome‐wide expression data from tumors and cell lines in breast cancer, together with drug response of cell lines, open prospects for integrative analyses that can lead to better personalized therapy. Drug responses and expression data collected from cell lines and tumors were used to generate tripartite networks connecting clusters of patients to cell lines and cell lines to drugs, to connect drugs to patients. Various approaches were applied to connect cell lines to tumor clusters: a standard method that uses a biomarker gene set, and new methods that compute metasignatures for transcription factors and histone modifications given upregulated genes in cell lines or tumors. The results from the metasignature analysis identify two major clusters of patients: one enriched for active histone marks and one for repressive marks. The tumors enriched for activation marks are correlated with poor prognosis. Overall, the analyses suggest new patient clustering, discover dysregulated pathways, and recommend individualized use of drugs to treat subsets of patients.

CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e35; doi:10.1038/psp.2013.11; advance online publication 27 March 2013
Compressive adaptive computational ghost imaging
Authors: Aβmann Marc , Bayer Manfred
Published: March 2013

Compressive sensing is considered a huge breakthrough in signal acquisition. It allows recording an image consisting of N2 pixels using much fewer than N2 measurements if it can be transformed to a basis where most pixels take on negligibly small values. Standard compressive sensing techniques suffer from the computational overhead needed to reconstruct an image with typical computation times between hours and days and are thus not optimal for applications in physics and spectroscopy. We demonstrate an adaptive compressive sampling technique that performs measurements directly in a sparse basis. It needs much fewer than N2 measurements without any computational overhead, so the result is available instantly.
Point-contact Andreev-reflection spectroscopy of doped manganites: Charge carrier spin-polarization and proximity effects (Review Article)
Authors: Krivoruchko V. N. , D'yachenko A. I. , Tarenkov V. Yu.
Published: March 2013

Materials with spin-polarized charge carriers are the most demanded in the spin-electronics. Particularly requested are the so-called half-metals which have the maximum attainable value of carrier spin polarization. Doped manganites are in the list of compounds with, potentially, half-metallic properties. The point-contact (PC) Andreev-reflection (AR) spectroscopy is a robust and direct method to measure the degree of current spin polarization. In this report, advances in PCAR spectroscopy of ferromagnetic manganites are reviewed. The experimental results obtained on “classic” s-wave superconductor—ferromagnetic manganites PCs, as well as related theoretical models applied to deduce the actual value of charge carrier spin-polarization, are discussed. Data obtained on “proximity affected” contacts is also outlined. Systematic and repeatable nature of a number of principal experimental facts detected in the AR spectrum of proximity affected contacts suggests that some new physical phenomena have been documented here. Different models of current flow through a superconductor–half-metal ferromagnet interface, as well as possibility of unconventional superconducting proximity effect, have been discussed.
Water proton configurations in structures I, II, and H clathrate hydrate unit cells
Authors: Takeuchi Fumihito , Hiratsuka Masaki , Ohmura Ryo , Alavi Saman , Sum Amadeu K. , Yasuoka Kenji
Published: March 2013

Position and orientation of water protons need to be specified when the molecular simulation studies are performed for clathrate hydrates. Positions of oxygen atoms in water are experimentally determined by X-ray diffraction analysis of clathrate hydrate structures, but positions of water hydrogen atoms in the lattice are disordered. This study reports a determination of the water proton coordinates in unit cell of structure I (sI), II (sII), and H (sH) clathrate hydrates that satisfy the ice rules, have the lowest potential energy configuration for the protons, and give a net zero dipole moment. Possible proton coordinates in the unit cell were chosen by analyzing the symmetry of protons on the hexagonal or pentagonal faces in the hydrate cages and generating all possible proton distributions which satisfy the ice rules. We found that in the sI and sII unit cells, proton distributions with small net dipole moments have fairly narrow potential energy spreads of about 1 kJ/mol. The total Coulomb potential on a test unit charge placed in the cage center for the minimum energy/minimum dipole unit cell configurations was calculated. In the sI small cages, the Coulomb potential energy spread in each class of cage is less than 0.1 kJ/mol, while the potential energy spread increases to values up to 6 kJ/mol in sH and 15 kJ/mol in the sII cages. The guest environments inside the cages can therefore be substantially different in the sII case. Cartesian coordinates for oxygen and hydrogen atoms in the sI, sII, and sH unit cells are reported for reference.
Tetrahedron deformation and alignment of perceived vorticity and strain in a turbulent flow
Authors: Pumir Alain , Bodenschatz Eberhard , Xu Haitao
Published: March 2013

We describe the structure and dynamics of turbulence by the scale-dependent perceived velocity gradient tensor as supported by following four tracers, i.e., fluid particles, that initially form a regular tetrahedron. We report results from experiments in a von Kármán swirling water flow and from numerical simulations of the incompressible Navier-Stokes equation. We analyze the statistics and the dynamics of the perceived rate of strain tensor and vorticity for initially regular tetrahedron of size r0 from the dissipative to the integral scale. Just as for the true velocity gradient, at any instant, the perceived vorticity is also preferentially aligned with the intermediate eigenvector of the perceived rate of strain. However, in the perceived rate of strain eigenframe fixed at a given time t = 0, the perceived vorticity evolves in time such as to align with the strongest eigendirection at t = 0. This also applies to the true velocity gradient. The experimental data at the higher Reynolds number suggests the existence of a self-similar regime in the inertial range. In particular, the dynamics of alignment of the perceived vorticity and strain can be rescaled by t0, the turbulence time scale of the flow when the scale r0 is in the inertial range. For smaller Reynolds numbers we found the dynamics to be scale dependent.
A combined matrix isolation spectroscopy and cryosolid positron moderation apparatus
Authors: Molek Christopher D. , Michael Lindsay C. , Fajardo Mario E.
Published: March 2013

We describe the design, construction, and operation of a novel apparatus for investigating efficiency improvements in thin-film cryogenic solid positron moderators. We report results from solid neon, argon, krypton, and xenon positron moderators which illustrate the capabilities and limitations of our apparatus. We integrate a matrix isolation spectroscopy diagnostic within a reflection-geometry positron moderation system. We report the optical thickness, impurity content, and impurity trapping site structures within our moderators determined from infrared absorption spectra. We use a retarding potential analyzer to modulate the flow of slow positrons, and report positron currents vs. retarding potential for the different moderators. We identify vacuum ultraviolet emissions from irradiated Ne moderators as the source of spurious signals in our channel electron multiplier slow positron detection channel. Our design is also unusual in that it employs a sealed radioactive Na-22 positron source which can be translated relative to, and isolated from, the cryogenic moderator deposition substrate. This allows us to separate the influences on moderator efficiency of surface contamination by residual gases from those of accumulated radiation damage.
Method of evaluating curvature-dependent elastic parameters for small unilamellar vesicles using molecular dynamics trajectory
Authors: Nakamura Takenobu , Shinoda Wataru
Published: March 2013

A numerical method is proposed for evaluating the curvature dependency of elastic parameters of a spherical vesicle based on a calculation of the pressure profile across the membrane. The proposed method is particularly useful for small unilamellar vesicles (SUVs), in which the internal structure of the membrane is asymmetric owing to the high curvature. In this case, the elastic energy is insufficiently described as a perturbation from a planar membrane. The calculated saddle-splay curvature modulus of SUVs, which is about 16 nm in diameter, is found to be much higher than that of a planar membrane. A comparison of the free energy change in the initial stage of vesicle-to-bicelle transformation with the Fromherz theory demonstrates that the elastic parameters estimated for SUVs provide better estimation of the free energy than those estimated for a planar membrane.
Knudsen layer formation in laser induced thermal desorption
Authors: Ikeda Akihiko , Matsumoto Masuaki , Ogura Shohei , Okano Tatsuo , Fukutani Katsuyuki
Published: March 2013

Laser induced thermal desorption of Xe atoms into vacuum from a metal surface following the nano-second pulsed laser heating was investigated by the time-of-flight (TOF) measurement. The desorption flow was studied at a wide range of desorption flux by varying the initially prepared Xe coverage Θ (1 ML = 4.5 × 1018 atoms/m2). At Θ = 0.3 ML, the TOF of Xe was well represented by a Maxwell-Boltzmann velocity distribution, which is in good agreement with thermal desorption followed by collision-free flow. At Θ > 0.3 ML, the peak positions of the TOF spectra were shifted towards the smaller values and became constant at large Θ, which were well fitted with a shifted Maxwell-Boltzmann velocity distribution with a temperature TD and a stream velocity u. With TD fixed at 165 K, u was found to increase from 80 to 125 m/s with increasing Θ from 1.2 to 4 ML. At Θ > 4 ML, the value of u becomes constant at 125 m/s. The converging feature of u was found to be consistent with analytical predictions and simulated results based on the Knudsen layer formation theory. We found that the Knudsen layer formation in laser desorption is completed at Knudsen number Kn <0.39.
On the Hamilton-Jacobi theory for singular lagrangian systems
Authors: de León Manuel , Marrero Juan Carlos , de Diego David Martín , Vaquero Miguel
Published: March 2013

We develop a Hamilton-Jacobi theory for singular lagrangian systems using the Gotay-Nester-Hinds constraint algorithm. The procedure works even if the system has secondary constraints.
Flux concentration and modulation based magnetoresistive sensor with integrated planar compensation coils
Authors: Tian Wugang , Hu Jiafei , Pan Mengchun , Chen Dixiang , Zhao Jianqiang
Published: March 2013

1/f noise is one of the main noise sources of magnetoresistive (MR) sensors, which can cause intrinsic detection limit at low frequency. To suppress this noise, the solution of flux concentration and vertical motion modulation (VMM) has been proposed. Magnetic hysteresis in MR sensors is another problem, which degrades their response linearity and detection ability. To reduce this impact, the method of pulse magnetization and magnetic compensation field with integrated planar coils has been introduced. A flux concentration and VMM based magnetoresistive prototype sensor with integrated planar coils was fabricated using microelectromechanical-system technology. The response linearity of the prototype sensors is improved from 0.8% to 0.12%. The noise level is reduced near to the thermal noise level, and the low-frequency detection ability of the prototype sensor is enhanced with a factor of more than 80.
Reduction of low-density lipoprotein cholesterol, plasma viscosity, and whole blood viscosity by the application of pulsed corona discharges and filtration
Authors: Jung Jin M. , Fridman Alexander , Cho Daniel J. , Cho Young I.
Published: March 2013

The present study investigated the feasibility of applying pulsed corona discharges to blood plasma to reduce the viscosity of blood plasma and whole blood. Blood plasma was separated from blood cells, treated with corona discharges, and filtered before it was re-mixed with blood cells. Plasma viscosity (PV), whole blood viscosity (WBV), and low-density lipoprotein (LDL)-c concentration were measured before and after the corona treatment and filtration. Both PV and WBV increased in the case of the corona treatment only, whereas both of them decreased in the case of the corona treatment plus filtration. In particular, the LDL-c decreased in the case of the corona treatment plus filtration by 31.5% from the baseline value. The effect of the corona treatment on the reduction of the WBV was significant at low shear rates, but not at high shear rates, suggesting that the precipitation of the molecules in blood plasma by the corona treatment and subsequent removal may suppress the aggregation of erythrocytes and improve rheological properties of blood.
Temperature measurements of heated microcantilevers using scanning thermoreflectance microscopy
Authors: Kim Joohyun , Han Sunwoo , Walsh Timothy , Park Keunhan , Jae Lee Bong , King William P. , Lee Jungchul
Published: March 2013

We report the development of scanning thermoreflectance thermometry and its application for steady and dynamic temperature measurement of a heated microcantilever. The local thermoreflectance signal of the heated microcantilever was calibrated to temperature while the cantilever was under steady and periodic heating operation. The temperature resolution of our approach is 0.6 K, and the spatial resolution is 2 μm, which are comparable to micro-Raman thermometry. However, the temporal resolution of our approach is about 10 μsec, which is significantly faster than micro-Raman thermometry. When the heated microcantilever is periodically heated with frequency up to 100 kHz, we can measure both the in-phase and out-of-phase components of the temperature oscillation. For increasing heating frequency, the measured cantilever AC temperature distribution tends to be confined in the vicinity of the heater region and becomes increasingly out of phase with the driving signal. These results compare well with finite element simulations.
On the changes at the Fe/MgO interface upon annealing
Authors: Martinez-Boubeta Carlos , Balcells Lluis , Martínez Benjamín
Published: March 2013

Experimental observation of the hybridization of oxygen p states with metal states at the interface in Fe/MgO core/shell self-assembled nanostructures, obtained by vapour-phase deposition, is reported. Synchrotron-based X-ray absorption spectroscopy techniques were used to directly probe the Fe orbital character at the interfacial region. O K edge features suggest the formation of metal-induced states within the band gap of MgO. Thermogravimetric analysis was also used to track interfacial phase changes after different annealing processes. These data demonstrate the relevant role of annealing protocols in controlling the barrier interface, which determine the actual characteristics of spin polarized tunnelling conduction processes.
High performance FeFx/C composites as cathode materials for lithium-ion batteries
Authors: Bai Ying , Yang Li-wei , Wu Feng , Wu Chuan , Chen Shi , Bao Li-ying , Hu Wen-long
Published: March 2013

FeFx precursors were synthesized by a simplified one-step hydrothermal synthesis route with commercial Fe(OH)3 and HF as raw materials; then the as-prepared precursor was calcined in different temperature and obtained FeF3, FeF2, and amorphous mixture FeF3-FeF2. These materials were characterized by X-ray diffraction, scanning electron microscope, and X-ray photoelectron spectroscopy and used as cathode materials for lithium-ion batteries. The electrochemical tests show that the initial discharge capacities of FeF3, FeF2, and amorphous mixture FeF3-FeF2 are as high as 204.6 mAh/g, 162 mAh/g, and 208.6 mAh/g, respectively, at the rate of 0.1 C in the range 2.0-4.5 V at 25 °C, and display very excellent discharge capacity retention rate after the first discharge process. Furthermore, the cyclic voltammogram test was used to illustrate the reaction mechanisms of the nanocomposites.
A critical review on state of charge of batteries
Authors: Yanhui Zhang , Wenji Song , Shili Lin , jie Lv , Ziping Feng
Published: March 2013

The accurate and reliable SOC (state of charge) estimation is difficult, although it is a core factor especially for battery energy storage system. Current studies of SOC estimation theories and models are mainly focused on voltage model, current model, resistance model, intelligent algorithm model, and hybrid model. Specific attentions were paid to estimate the model and their impact factors on SOC. Then, a critical review of available literature on major SOC issues was presented. Influencing factors on SOC were studied and analyzed, such as dynamic hysteresis characteristics, temperature, aging, self-discharge, and rate of charge/discharge. The economy and practicability of the SOC estimation are analyzed and compared objectively.
Economic analysis of solar chimney power plants in Northwest China
Authors: Cao Fei , Li Huashan , Zhao Liang , Guo Liejin
Published: March 2013

Solar chimney power plant (SCPP) with a long life span is a promising large-scale solar thermal utilization technology. This paper performs an economic analysis for the conventional solar chimney power plant (CSCPP) and the sloped solar chimney power plant (SSCPP) in Northwest China. Cash flows are influenced by many factors including the investment, the payback period, the inflation rate, and the sale price of solar electricity. The techno-economic analyses of the CSCPPs and SSCPPs are performed taking Lanzhou, China as a case study. The results show that the SCPP investment is influenced by both its configuration and the material price, and the SSCPP is more cost-effective than the CSCPP during the system life span. In addition, the SCPP with large power capacity holds good competitiveness with the conventional fossil fuel combustion plants. The economic evaluation of building SCPPs in Northwest China is of high significance considering the local abundant solar radiation, favorable government policy, and under-developing economics.
Solvothermal synthesis of boron-doped graphene and nitrogen-doped graphene and their electrical properties
Authors: Zhu Qianqian , Yu Jianhua , Zhang Wushou , Dong Hongzhou , Dong Lifeng
Published: March 2013

In this work, pristine graphene, nitrogen-doped graphene and boron-doped graphene were synthesized by a facile solvothermal process using potassium or lithium nitride as catalyst. The formation mechanism of graphene and doped graphene was discussed, and the chlorine gas generated during the reaction performed a significant role. High yield of graphene and doped graphene can be produced via the solvothermal route with relatively mild conditions, and X-ray photoelectron energy spectroscopy analysis confirmed the doping status and concentration of nitrogen or boron within graphene sheets. Especially, electrical properties of graphene-based field effect transistors revealed that the introduction of nitrogen or boron atoms into graphene sheets can effectively tailor electrical property of graphene from conducting characteristics to semiconducting behaviors.
Effect of temperature and gas flow on the efficiency of an air bottoming cycle
Authors: Teflissi R. , Ataei A.
Published: March 2013

The objective of this research is to analyze the performance of an Air Bottoming Cycle (ABC) by considering the effect of temperature and gas flow. Based on the energetic analysis, a thermodynamic calculation has been performed to investigate improving the thermal efficiency of the ABC. In this research, we consider the full cycle should consist of two sub-cycles: Braysson and Joule. The flue gas from the top cycle is used in Braysson cycle turbine to generate power and the rest of the energy of this flow is exchanged to the pressurized Joule cycle air flow. The results indicate that the higher inlet temperatures of the Braysson turbine and lower Braysson turbine outlet temperatures lead to higher thermal efficiencies. Moreover, the lower overall pressure ratios in Joule cycle are required to achieve the higher overall thermal efficiencies. The maximum thermal efficiency and also the optimal design point of this ABC have been found. The results of this ABC analysis show an increase in net output work and the thermal efficiency up to more than 55%, which in turn leads to have less specific fuel consumption. The proposed cycle has been found to have more energy recovery potential compared to some other gas turbine based ABCs. Besides, in contrast to common steam bottom cycles, some water can be generated using the flue gas stream which is important because the lack of water resources is going to be a major problem in many regions worldwide.
Effects of coherent ferroelastic domain walls on the thermal conductivity and Kapitza conductance in bismuth ferrite
Authors: Hopkins Patrick E. , Adamo Carolina , Ye Linghan , Huey Bryan D. , Lee Stephen R. , Schlom Darrell G. , Ihlefeld Jon F.
Published: March 2013

Ferroelectric and ferroelastic domain structure has a profound effect on the piezoelectric, ferroelectric, and dielectric responses of ferroelectric materials. However, domain walls and strain field effects on thermal properties are unknown. We measured the thermal conductance from 100–400 K of epitaxially grown BiFeO3 thin films with different domain variants, each separated primarily by 71° domain walls. We determined the Kapitza conductance across the domain walls, which is driven by the strain field induced by the domain variants. This domain wall Kapitza conductance is lower than the Kapitza conductance associated with grain boundaries in all previously measured materials.
Femtosecond streaking of electron diffraction patterns to study structural dynamics in crystalline matter
Authors: Eichberger M. , Erasmus N. , Haupt K. , Kassier G. , von Flotow A. , Demsar J. , Schwoerer H.
Published: March 2013

A table-top femtosecond, non-relativistic, electron diffraction setup is combined with a low-jitter, photo-triggered streak camera to follow the optically induced structural dynamics in complex solids. A temporal resolution of 550 fs is experimentally demonstrated, while the route to streaking with sub-250 fs temporal resolution is outlined. The streaking technique allows for parallel capturing of temporal information as opposed to the serial data acquisition in a conventional scanning femtosecond electron diffraction. Moreover, its temporal resolution is not corrupted by increasing the number of electrons per pulse. Thus, compared to the conventional scanning approach, a substantial increase in signal-to-noise ratio (SNR) can be achieved. These benefits are demonstrated by studying a photo-induced charge density wave phase transition in 4Hb-TaSe2 using both methods. Within the same data acquisition time a three-fold increase in SNR is achieved when compared to the scanning method, with ways for a further improvement outlined.
A controllable collapsed/circular nanoactuator based on carbon nanotube
Authors: Kou Jianlong , Zhou Xiaoyan , Fang Yunzhang , Chen Yanyan , Lu Hangjun , Ye Huiqun , Wu Fengmin , Fan Jintu
Published: March 2013

We performed molecular dynamics simulations to investigate the transformation between collapsed and circular cross-sectioned single walled carbon nanotube (SWCNT). It is shown that, by tuning the surface energy of SWCNT via an external field, the shape of a SWCNT can be transformed from the collapsed form to circular cross-sectioned form or vice versa, demonstrating promising applications as actuators and motors in nanomechanical systems. Phase diagrams of the surface energy threshold with varying diameters of the SWCNT and environmental temperature were computed, providing quantitative guidelines for the design of such a nanoactuator.
Temperature dependence of photoluminescence from InNAsSb layers: The role of localized and free carrier emission in determination of temperature dependence of energy gap
Authors: Latkowska M. , Kudrawiec R. , Janiak F. , Motyka M. , Misiewicz J. , Zhuang Q. , Krier A. , Walukiewicz W.
Published: March 2013

The temperature dependence of energy gap-related emission from InNAsSb layers was studied by Fourier transform infrared photoluminescence (PL) spectroscopy. The shape of PL peak was analyzed using a theoretical expression, which takes into account both the localized and free carrier emission. Proper accounting for those two effects is very important for an accurate determination of the Varshni and Bose-Einstein parameters from PL data. It is shown that nitrogen incorporation has a very week effect on the temperature induced bandgap reduction in InNAsSb alloys and that the Varshni and Bose-Einstein parameters are very close to those observed in InAs and InSb.
Suppression of pointing instability in quantum cascade lasers by transverse mode control
Authors: Bouzi Pierre M. , Liu Peter Q. , Aung Nyan , Wang Xiaojun , Fan Jen-Yu , Troccoli Mariano , Gmachl Claire F.
Published: March 2013

We report on a technique that serves to eliminate pointing instability in Quantum Cascade lasers by suppressing the propagation of higher order transverse modes within the laser cavity. This process, achieved via a short and lossy lateral constriction in the waveguide, only allows the fundamental mode to propagate. The beam pointing fluctuations of the modified devices are greatly reduced, with a 10-fold improvement in standard deviation, indicating a stable emitted beam. The far-field pattern has a Gaussian shape, and the slope efficiency of the received power on a 0.87 numerical aperture detector increases by ∼65%, without significant increase in threshold.
Real-time quantitative terahertz microfluidic sensing based on photonic crystal pillar array
Authors: Fan Fei , Gu Wen-Hao , Wang Xiang-Hui , Chang Sheng-Jiang
Published: March 2013

The microfluidic sensing based on the photonic crystal (PC) pillar array was investigated in the terahertz (THz) region. We fabricated the silicon PC sensors, and experimentally and theoretically demonstrated their resonances by using the THz time-domain spectroscopy system. According to the corresponding changes of the resonances dependent on the different microfluidics on the PC sensor, the qualitative monitoring can be achieved. By establishing the relation between the experimental data and simulations, the amount of microfluidic at each moment on the different PC sensors can be exactly determined. These PC sensors have great promising potential in the real-time quantitative sensing.
Large rotary dairies achieve high cow throughput but are not more labour efficient than medium-sized rotaries
Authors: Edwards J. P. , Jago J. G. , Lopez-Villalobos N.
Published: March 2013

It was hypothesised that large rotary dairies (>60 clusters) are not more operator efficient than medium-sized rotaries (40–60 clusters). This was tested by collecting and analysing milking data, during peak and late lactation, from block calving herds milked in rotary dairies fitted with electronic milk meters. Data were collected from a total of 61 unique farms around New Zealand, with rotary dairies ranging in size from 28 to 80 clusters, for two 5-day periods during spring (September–November 2010; 47 farms; average milk yield 23.1 kg/day) and autumn (February–April 2011; 60 farms; average milk yield 16.4 kg/day). A telephone survey was conducted to collect basic farm details: size, land area, the number of herds managed (including hospital herds), number of operators in the dairy and total labour input. A site visit was conducted to collect data such as the number of bails/stalls over the entrance and exit of the platform. The herd management software on each farm was programmed to record similar fields for each of the six machine manufacturers represented. Variables recorded included cow, date, identification time, bail number, milk yield, milking duration, and average milk flow rate. Calculations were performed to determine the number of cows milked and milk harvested per hour as well as the operator efficiency values for these measures and an estimate of cluster utilisation. Mixed models were used to determine the relationship between the dependent variables, cows milked per hour, milk harvested per hour, cows milked per operator per hour, milk harvested per operator per hour, and cluster utilisation, and the independent variables collected. Cows milked and milk harvested per hour increased linearly with rotary size, during both spring and autumn and there was a quadratic relationship between operator efficiency measures and rotary size, which peaked at ~60 clusters. Cluster utilisation, the amount of time clusters were harvesting milk out of the plant running time, was estimated at 46 ± 6%. Larger rotary dairies on average achieved greater throughput; however, they were not more operator efficient than medium-sized rotaries. Thus, large rotary dairies are best suited to farms where the additional throughput is required.
Limited impact of fragmentation and disturbance on the mating system of tuart (Eucalyptus gomphocephala, Myrtaceae): implications for seed-source quality in ecological restoration
Authors: Bradbury Donna , Krauss Siegfried L.
Published: March 2013

Variation in patterns of mating within and among plant populations can be impacted by habitat disturbance and have significant implications for offspring fitness. An understanding of this variation will inform predictions of seed genetic quality, benefiting ecological restoration through better seed-sourcing guidelines. We assessed mating system variation in six populations of tuart (Eucalyptus gomphocephala DC.), an iconic tree of significance to ecological restoration in Western Australia. A mixed mating system was observed with predominant outcrossing (tm = 0.76 ± 0.05) and low biparental inbreeding (tm–ts = 0.03 ± 0.02). We detected some evidence of increased inbreeding in a naturally fragmented population (tm–ts = 0.10 ± 0.04) and in a disturbed urban remnant (tm = 0.52 ± 0.12), including a family with complete selfing. However, most variation in outcrossing rate occurred among individuals within populations (82%), rather than among populations (2.6%) or among groups of populations defined by fragmentation or disturbance (15.4%). Genetic diversity was not consistently lower in offspring from fragmented, smaller and/or disturbed populations. These data reinforce the importance of sourcing seeds from multiple trees for ecological restoration, and emphasise that tuart’s mating system and the genetic diversity of offspring is robust to some habitat disturbance and/or fragmentation.
The human placenta methylome
Authors: Schroeder Diane I. , Blair John D. , Lott Paul , Yu Hung On Ken , Hong Danna , Crary Florence , Ashwood Paul , Walker Cheryl , Korf Ian , Robinson Wendy P. , LaSalle Janine M.
Published: March 2013

Tissue-specific DNA methylation is found at promoters, enhancers, and CpG islands but also over larger genomic regions. In most human tissues, the vast majority of the genome is highly methylated (>70%). Recently, sequencing of bisulfite-treated DNA (MethylC-seq) has revealed large partially methylated domains (PMDs) in some human cell lines. PMDs cover up to 40% of the genome and are associated with gene repression and inactive chromatin marks. However, to date, only cultured cells and cancers have shown evidence for PMDs. Here, we performed MethylC-seq in full-term human placenta and demonstrate it is the first known normal tissue showing clear evidence of PMDs. We found that PMDs cover 37% of the placental genome, are stable throughout gestation and between individuals, and can be observed with lower sensitivity in Illumina 450K Infinium data. RNA-seq analysis confirmed that genes in PMDs are repressed in placenta. Using a hidden Markov model to map placental PMDs genome-wide and compare them to PMDs in other cell lines, we found that genes within placental PMDs have tissue-specific functions. For regulatory regions, methylation levels in promoter CpG islands are actually higher for genes within placental PMDs, despite the lower overall methylation of surrounding regions. Similar to PMDs, polycomb-regulated regions are hypomethylated but smaller and distinct from PMDs, with some being hypermethylated in placenta compared with other tissues. These results suggest that PMDs are a developmentally dynamic feature of the methylome that are relevant for understanding both normal development and cancer and may be of use as epigenetic biomarkers.
Disruption of the principal, progesterone-activated sperm Ca
2+
channel in a CatSper2-deficient infertile patient
Authors: Smith James F. , Syritsyna Olga , Fellous Marc , Serres Catherine , Mannowetz Nadja , Kirichok Yuriy , Lishko Polina V.
Published: March 2013

The female steroid hormone progesterone regulates ovulation and supports pregnancy, but also controls human sperm function within the female reproductive tract. Progesterone causes elevation of sperm intracellular Ca
2+
leading to sperm hyperactivation, acrosome reaction, and perhaps chemotaxis toward the egg. Although it has been suggested that progesterone-dependent Ca
2+
influx into human spermatozoa is primarily mediated by cationic channel of sperm (CatSper), the principal flagellar Ca
2+
channel of sperm, conclusive loss-of-function genetic evidence for activation of CatSper by progesterone has yet to be provided. Moreover, it is not clear whether the responsiveness of CatSper to progesterone is an innate property of human spermatozoa or is acquired as the result of exposure to the seminal plasma. Here, by recording ionic currents from spermatozoa of an infertile CatSper-deficient patient, we demonstrate that CatSper is indeed the principal Ca
2+
channel of human spermatozoa, and that it is strongly potentiated by progesterone. In addition, by recording CatSper currents from human epididymal and testicular spermatozoa, we show that CatSper sensitivity to progesterone arises early in sperm development and increases gradually to a peak when spermatozoa are ejaculated. These results unambiguously establish an important role of CatSper channel in human sperm nongenomic progesterone signaling and demonstrate that the molecular mechanism responsible for activation of CatSper by progesterone arises early in sperm development concurrently with the CatSper channel itself.
Spatial partitioning improves the reliability of biochemical signaling
Authors: Mugler Andrew , Tostevin Filipe , ten Wolde Pieter Rein
Published: March 2013

Spatial heterogeneity is a hallmark of living systems, even at the molecular scale in individual cells. A key example is the partitioning of membrane-bound proteins via lipid domain formation or cytoskeleton-induced corralling. However, the impact of this spatial heterogeneity on biochemical signaling processes is poorly understood. Here, we demonstrate that partitioning improves the reliability of biochemical signaling. We exactly solve a stochastic model describing a ubiquitous motif in membrane signaling. The solution reveals that partitioning improves signaling reliability via two effects: it moderates the nonlinearity of the switching response, and it reduces noise in the response by suppressing correlations between molecules. An optimal partition size arises from a trade-off between minimizing the number of proteins per partition to improve signaling reliability and ensuring sufficient proteins per partition to maintain signal propagation. The predicted optimal partition size agrees quantitatively with experimentally observed systems. These results persist in spatial simulations with explicit diffusion barriers. Our findings suggest that molecular partitioning is not merely a consequence of the complexity of cellular substructures, but also plays an important functional role in cell signaling.
Evidence that Igf2 down-regulation in postnatal tissues and up-regulation in malignancies is driven by transcription factor E2f3
Authors: Lui Julian C. , Baron Jeffrey
Published: March 2013

Insulin-like growth factor 2 (IGF2) is an important fetal growth factor. Its expression is dramatically down-regulated in multiple organs after birth but is frequently up-regulated in cancers. The mechanisms that drive down-regulation of IGF2 in postnatal tissues or the up-regulation in malignancy are unclear. We found evidence that E2F transcription factor 3 (E2F3) drives these changes in expression. E2f3 mRNA expression, protein expression, and binding to the Igf2 promoter all decreased with age postnatally in multiple mouse organs. In late juvenile hepatocytes, restoration of high E2f3 expression restored high Igf2 expression, indicating a causal relationship, but this induction did not occur in fetal hepatocytes, which already have high E2f3 and Igf2 expression. Transient expression of E2f3 in both HEK293 cells and in late juvenile hepatocytes were able to activate reporter constructs containing the mouse Igf2 promoter P2, which includes consensus E2F-binding sites. In humans, microarray data revealed declines in E2F3 and IGF2 expression with age similar to the mouse. In addition, E2F3-overexpressing human prostate and bladder cancers showed increased IGF2 expression, and levels of E2F3 and IGF2 mRNA in these cancers were positively correlated. Taken together, the findings suggest that down-regulation of E2f3 with age helps drive the dramatic decline in Igf2 expression in postnatal organs, and E2F3 overexpression in human cancers induces IGF2 overexpression.
Transformation of social networks in the late pre-Hispanic US Southwest
Authors: Mills Barbara J. , Clark Jeffery J. , Peeples Matthew A. , Haas W. R. , Roberts John M. , Hill J. Brett , Huntley Deborah L. , Borck Lewis , Breiger Ronald L. , Clauset Aaron , Shackley M. Steven
Published: March 2013

The late pre-Hispanic period in the US Southwest (A.D. 1200–1450) was characterized by large-scale demographic changes, including long-distance migration and population aggregation. To reconstruct how these processes reshaped social networks, we compiled a comprehensive artifact database from major sites dating to this interval in the western Southwest. We combine social network analysis with geographic information systems approaches to reconstruct network dynamics over 250 y. We show how social networks were transformed across the region at previously undocumented spatial, temporal, and social scales. Using well-dated decorated ceramics, we track changes in network topology at 50-y intervals to show a dramatic shift in network density and settlement centrality from the northern to the southern Southwest after A.D. 1300. Both obsidian sourcing and ceramic data demonstrate that long-distance network relationships also shifted from north to south after migration. Surprisingly, social distance does not always correlate with spatial distance because of the presence of network relationships spanning long geographic distances. Our research shows how a large network in the southern Southwest grew and then collapsed, whereas networks became more fragmented in the northern Southwest but persisted. The study also illustrates how formal social network analysis may be applied to large-scale databases of material culture to illustrate multigenerational changes in network structure.
Ligand-functionalized nanoparticles target endothelial cells in retinal capillaries after systemic application
Authors: Pollinger Klaus , Hennig Robert , Ohlmann Andreas , Fuchshofer Rudolf , Wenzel Rebecca , Breunig Miriam , Tessmar Joerg , Tamm Ernst R. , Goepferich Achim
Published: March 2013

To date, diseases affecting vascular structures in the posterior eye are mostly treated by laser photocoagulation and multiple intraocular injections, procedures that destroy healthy tissue and can cause vision-threatening complications. To overcome these drawbacks, we investigate the feasibility of receptor-mediated nanoparticle targeting to capillary endothelial cells in the retina after i.v. application. Cell-binding studies using microvascular endothelial cells showed receptor-specific binding and cellular uptake of cyclo(RGDfC)-modified quantum dots via the αvβ3 integrin receptor. Conversely, Mueller cells and astrocytes, representing off-target cells located in the retina, revealed only negligible interaction with nanoparticles. In vivo experiments, using nude mice as the model organism, demonstrated a strong binding of the ligand-modified quantum dots in the choriocapillaris and intraretinal capillaries upon i.v. injection and 1-h circulation time. Nontargeted nanoparticles, in contrast, did not accumulate to a significant amount in the target tissue. The presented strategy of targeting integrin receptors in the retina could be of utmost value for future intervention in pathologies of the posterior eye, which are to date only accessible with difficulty.