bluuebunny/crossref_metadata_2025 huggingface dataset:
Penance, submission and deditio: religious influences on dispute settlement in later Anglo-Saxon England (871–1066)
Authors: Roach Levi
Published: July 2013

Starting with evidence from law-codes, this article traces how penance was increasingly integrated into later Anglo-Saxon legal culture, arguing that this process opened the way for ritualized acts of satisfaction to become a regular feature of contemporary dispute settlement. The rituals used in such contexts often borrowed symbols and concepts from the world of penance, with the central idea being that an offender who repented and humbled himself was worthy of pardon. A few detailed accounts of such settlements survive and to these we may add cases of restitution and political reconciliation, which witness a similar logic. Taken together, these suggest that the stark contrasts often drawn between English and continental (particularly German) disputing in these years are in need of some revision. Far from being ‘fiercely punitive’, later Anglo-Saxon justice was characterized by a complex mix of formalized punishments and more informal means of settlement, not unlike what is visible in the Ottonian Reich.
Neural Correlates of Cognitive Fatigue: Cortico-Striatal Circuitry and Effort–Reward Imbalance
Authors: Dobryakova Ekaterina , DeLuca John , Genova Helen M. , Wylie Glenn R.
Published: July 2013

Recently, there has been renewed interest in the study of cognitive fatigue. It is known that fatigue is one of the most disabling symptoms in numerous neurological populations, including stroke, multiple sclerosis, Parkinson's disease, and traumatic brain injury. Behavioral studies of cognitive fatigue are hampered by lack of correlation of self-report measures with objective performance. Neuroimaging studies provide new insight about cognitive fatigue and its neural correlates. Impairment within the cortico-striatal network, involved in effort–reward calculation, has been suggested to be critically related to fatigue. The current review surveys the recent neuroimaging literature, and suggests promising avenues for future research. (JINS, 2013,19, 1–5)
Hyperglycemia Accelerates Apparent Diffusion Coefficient-Defined Lesion Growth after Focal Cerebral Ischemia in Rats with and Without Features of Metabolic Syndrome
Authors: Tarr David , Graham Delyth , Roy Lisa A , Holmes William M , McCabe Christopher , Macrae I Mhairi , Muir Keith W , Dewar Deborah
Published: July 2013

Poststroke hyperglycemia is associated with a poor outcome yet clinical management is inadequately informed. We sought to determine whether clinically relevant levels of hyperglycemia exert detrimental effects on the early evolution of focal ischemic brain damage, as determined by magnetic resonance imaging, in normal rats and in those modeling the ‘metabolic syndrome’. Wistar Kyoto (WKY) or fructose-fed spontaneously hypertensive stroke-prone (ffSHRSP) rats were randomly allocated to groups for glucose or vehicle administration before permanent middle cerebral artery occlusion. Diffusion-weighted imaging was carried out over the first 4 hours after middle cerebral artery occlusion and lesion volume calculated from apparent diffusion coefficient maps. Infarct volume and immunostaining for markers of oxidative stress were measured in the fixed brain sections at 24 hours. Hyperglycemia rapidly exacerbated early ischemic damage in both WKY and ffSHRSP rats but increased infarct volume only in WKY rats. There was only limited evidence of oxidative stress in hyperglycemic animals. Acute hyperglycemia, at clinically relevant levels, exacerbates early ischemic damage in both normal and metabolic syndrome rats. Management of hyperglycemia may have greatest benefit when performed in the acute phase after stroke in the absence or presence of comorbidities.
Glutamatergic and GABAergic TCA Cycle and Neurotransmitter Cycling Fluxes in Different Regions of Mouse Brain
Authors: Tiwari Vivek , Ambadipudi Susmitha , Patel Anant B
Published: July 2013

The 13C nuclear magnetic resonance (NMR) studies together with the infusion of 13C-labeled substrates in rats and humans have provided important insight into brain energy metabolism. In the present study, we have extended a three-compartment metabolic model in mouse to investigate glutamatergic and GABAergic tricarboxylic acid (TCA) cycle and neurotransmitter cycle fluxes across different regions of the brain. The 13C turnover of amino acids from [1,6-13C2]glucose was monitored ex vivo using qH-[13C]-NMR spectroscopy. The astroglial glutamate pool size, one of the important parameters of the model, was estimated by a short infusion of [2-13C]acetate. The ratio Vcyc/VTCA was calculated from the steady-state acetate experiment. The 13C turnover curves of [4-13C]/[3-13C]glutamate, [4-13C]glutamine, [2-13C]/[3-13C]GABA, and [3-13C]aspartate from [1,6-13C2]glucose were analyzed using a three-compartment metabolic model to estimate the rates of the TCA cycle and neurotransmitter cycle associated with glutamatergic and GABAergic neurons. The glutamatergic TCA cycle rate was found to be highest in the cerebral cortex (0.91±0.05 μmol/g per minute) and least in the hippocampal region (0.64±0.07 μmol/g per minute) of the mouse brain. In contrast, the GABAergic TCA cycle flux was found to be highest in the thalamus-hypothalamus (0.28±0.01 μmol/g per minute) and least in the cerebral cortex (0.24±0.02 μmol/g per minute). These findings indicate that the energetics of excitatory and inhibitory function is distinct across the mouse brain.
Decreased in vitro Mitochondrial Function is Associated with Enhanced Brain Metabolism, Blood Flow, and Memory in Surfl-Deficient Mice
Authors: Lin Ai-Ling , Pulliam Daniel A , Deepa Sathyaseelan S , Halloran Jonathan J , Hussong Stacy A , Burbank Raquel R , Bresnen Andrew , Liu Yuhong , Podlutskaya Natalia , Soundararajan Anuradha , Muir Eric , Duong Timothy Q , Bokov Alex F , Viscomi Carlo , Zeviani Massimo , Richardson Arlan G , Van Remmen Holly , Fox Peter T , Galvan Veronica
Published: July 2013

Recent studies have challenged the prevailing view that reduced mitochondrial function and increased oxidative stress are correlated with reduced longevity. Mice carrying a homozygous knockout (KO) of the Surf1 gene showed a significant decrease in mitochondrial electron transport chain Complex IV activity, yet displayed increased lifespan and reduced brain damage after excitotoxic insults. In the present study, we examined brain metabolism, brain hemodynamics, and memory of Surf1 KO mice using in vitro measures of mitochondrial function, in vivo neuroimaging, and behavioral testing. We show that decreased respiration and increased generation of hydrogen peroxide in isolated Surf1 KO brain mitochondria are associated with increased brain glucose metabolism, cerebral blood flow, and lactate levels, and with enhanced memory in Surf1 KO mice. These metabolic and functional changes in Surf1 KO brains were accompanied by higher levels of hypoxia-inducible factor 1 alpha, and by increases in the activated form of cyclic AMP response element-binding factor, which is integral to memory formation. These findings suggest that Surf1 deficiency-induced metabolic alterations may have positive effects on brain function. Exploring the relationship between mitochondrial activity, oxidative stress, and brain function will enhance our understanding of cognitive aging and of age-related neurologic disorders.
Critically evaluated rate coefficients in radical polymerization – 7. Secondary-radical propagation rate coefficients for methyl acrylate in the bulk
Authors: Barner-Kowollik Christopher , Beuermann Sabine , Buback Michael , Castignolles Patrice , Charleux Bernadette , Coote Michelle L. , Hutchinson Robin A. , Junkers Tanja , Lacík Igor , Russell Gregory T. , Stach Marek , van Herk Alex M.
Published: July 2013

Benchmark propagation rate coefficient (kp) data for the radical polymerization of methyl acrylate are provided.
Preschool Teachers' Perception and Use of Hearing Assistive Technology in Educational Settings
Authors: Nelson Lauri H. , Poole Bridget , Muñoz Karen
Published: July 2013

Purpose

This study explored how often sound-field amplification and personal frequency-modulated (FM) systems are used in preschool classrooms, teacher perceptions of advantages and disadvantages of using hearing assistive technology, and teacher recommendations for hearing assistive technology use.

Method

The study used a cross-sectional survey design. Participants were professionals who provided services to preschool-age children who are deaf or hard of hearing in public or private schools. A total of 306 surveys were sent to 162 deaf education programs throughout the United States; 99 surveys were returned (32%). Simple statistics were used to describe the quantitative survey results; content analysis was completed on open-ended survey comments.

Results

Surveys were received from teachers working at listening and spoken language preschool programs (65%) and at bilingual–bicultural and total communication preschool programs (35%). Most respondents perceived that hearing assistive technology improved students' academic performance, speech and language development, behavior, and attention in the classroom. The majority of respondents also reported that they definitely would or probably would recommend a sound-field system (77%) or personal FM system (71%) to other educators.

Conclusion

Hearing assistive technology is frequently used in preschool classrooms of children who are deaf or hard of hearing, with generally positive teacher perceptions of the benefits of using such technology.
Acoustic Predictors of Intelligibility for Segmentally Interrupted Speech: Temporal Envelope, Voicing, and Duration
Authors: Fogerty Daniel
Published: July 2013

Purpose

Temporal interruption limits the perception of speech to isolated temporal glimpses. An analysis was conducted to determine the acoustic parameter that best predicts speech recognition from temporal fragments that preserve different types of speech information—namely, consonants and vowels.

Method

Young listeners with normal hearing previously completed word and sentence recognition tasks that required them to repeat word and sentence material that was temporally interrupted. Interruptions were designed to replace various portions of consonants or vowels with low-level noise. Acoustic analysis of preserved consonant and vowel segments was conducted to investigate the role of the preserved temporal envelope, voicing, and speech duration in predicting performance.

Results

Results demonstrate that the temporal envelope, predominantly from vowels, is most important for sentence recognition and largely predicts results across consonant and vowel conditions. In contrast, for isolated words the proportion of speech preserved was the best predictor of performance regardless of whether glimpses were from consonants or vowels.

Conclusion

These findings suggest consideration of the vowel temporal envelope in speech transmission and amplification technologies for improving the intelligibility of temporally interrupted sentences.
Modeling of non-equilibrium phenomena in expanding flows by means of a collisional-radiative model
Authors: Munafò A. , Lani A. , Bultel A. , Panesi M.
Published: July 2013

The effects of non-equilibrium in a quasi-one-dimensional nozzle flow are investigated by means of a collisional-radiative model. The gas undergoing the expansion is an air plasma and consists of atoms, molecules, and free electrons. In the present analysis, the electronic excited states of atomic and molecular species are treated as separate pseudo-species. Rotational and vibrational energy modes are assumed to be populated according to Boltzmann distributions. The coupling between radiation and gas dynamics is accounted for, in simplified manner, by using escape factors. The flow governing equations for the steady quasi-one-dimensional flow are written in conservative form and discretized in space by means of a finite volume method. Steady-state solutions are obtained by using a fully implicit time integration scheme. The analysis of the evolution of the electronic distribution functions reveals a substantial over-population of the high-lying excited levels of atoms and molecules in correspondence of the nozzle exit. The influence of optical thickness is also studied. The results clearly demonstrate that the radiative transitions, within the optically thin approximation, drastically reduce the over-population of high-lying electronic levels.
Quantum dephasing of a two-state system by a nonequilibrium harmonic oscillator
Authors: Martens Craig C.
Published: July 2013

In this paper, we investigate coherent quantum dynamics in a nonequilibrium environment. We focus on a two-state quantum system strongly coupled to a single classical environmental oscillator, and explore the effect of nonstationary statistical properties of the oscillator on the quantum evolution. A simple nonequilibrium model, consisting of an oscillator with a well-defined initial phase which undergoes subsequent diffusion, is introduced and studied. Approximate but accurate analytic expressions for the evolution of the off-diagonal density matrix element of the quantum system are derived in the second-order cumulant approximation. The effect of the initial phase choice on the subsequent quantum evolution is quantified. It is observed that the initial phase can have a significant effect on the preservation of coherence on short time scales, suggesting this variable as a control parameter for optimizing coherence in many-body quantum systems.
Attenuation of shock waves propagating through nano-structured porous materials
Authors: Al-Qananwah Ahmad K. , Koplik Joel , Andreopoulos Yiannis
Published: July 2013

Porous materials have long been known to be effective in energy absorption and shock wave attenuation. These properties make them attractive in blast mitigation strategies. Nano-structured materials have an even greater potential for blast mitigation because of their high surface-to-volume ratio, a geometric parameter which substantially attenuates shock wave propagation. A molecular dynamics approach was used to explore the effects of this remarkable property on the behavior of traveling shocks impacting on solid materials. The computational setup included a moving piston, a gas region and a target solid wall with and without a porous structure. The gas and porous solid were modeled by Lennard-Jones-like and effective atom potentials, respectively. The shock wave is resolved in space and time and its reflection from a solid wall is gradual, due to the wave's finite thickness, and entails a self-interaction as the reflected wave travels through the incoming incident wave. Cases investigated include a free standing porous structure, a porous structure attached to a wall and porous structures with graded porosity. The effects of pore shape and orientation have been also documented. The results indicate that placing a nano-porous material layer in front of the target wall reduced the stress magnitude and the energy deposited inside the solid by about 30 percent, while at the same time substantially decreasing the loading rate.
Large electrostrictive effect in ternary Bi0.5Na0.5TiO3-based solid solutions
Authors: Wang Feifei , Jin Chengchao , Yao Qirong , Shi Wangzhou
Published: July 2013

In the present work, a ternary solid solution (0.935-x)Bi0.5Na0.5TiO3-0.065BaTiO3-xSrTiO3 (BNBST, BNBSTx) was designed and fabricated using the traditional solid state reaction method. A morphotropic phase boundary between the ferroelectric long-range-order and relaxor pseudocubic phases was determined around x of 0.22 for poled solid solutions. The further increase of SrTiO3 substitution turned the depolarization temperature Td to below ambient temperature and led to a sharp decrease in the remnant polarization Pr and quasi-static piezoelectric constant d33. A large electrostrictive coefficient Q of 0.026 m4 C−2 was obtained for BNBST0.30, which was entirely comparable to the well-known electrostrictive material Pb(Mg1/3Nb2/3)O3, recently reported Bi0.5Na0.5TiO3-BaTiO3-K0.5Na0.5NbO3, and Bi0.5Na0.5TiO3-BaTiO3-KNbO3. Under a moderate electric field of 4 kV/mm, the electrostrictive strain can reach as high as ∼0.11%. Furthermore, the electric-field-induced strain exhibited weak temperature-dependent behavior. The large electrostrictive strain was suggested to be ascribed to the formation of relaxor pseudocubic phase developed by the SrTiO3 substitution and the high electrostrictive coefficient of BNBST ceramics makes them great potential to be applied to the environmental-friendly solid-state actuators.
Enhancing electrical properties of LiNbO3/AlGaN/GaN transistors by using ZnO buffers
Authors: Hao Lanzhong , Li Yanrong , Zhu Jun , Wu Zhipeng , Deng Jie , Zeng Huizhong , Zhang Jihua , Liu Xingzhao , Zhang Wanli
Published: July 2013

LiNbO3 (LN) ferroelectric films were deposited on the ZnO buffered AlGaN/GaN templates by pulse laser deposition technique. The microstructures of the buffer layers and LN films were characterized by reflective high energy electron diffraction, atomic force microscope, and X-ray diffraction, respectively. With the help of Cu/Si3N4 double-layer masks, LN/ZnO/AlGaN/GaN transistors were fabricated and the electrical properties were studied. Normally off characteristics were exhibited for the fabricated transistors with LN gate layers. Due to the modifications of the 5-nm-thick ZnO layer to the interface, the electrical properties of the transistor were enhanced greatly. The maximum transconductance increased from 27 to 46 mS/mm, and the maximum drain current increased from 97 to 204 mA/mm. The operation mechanisms of the devices were proposed by the numerical calculations of the electronic band structure and charge distribution.
Eddy-current effect on resonant magnetoelectric coupling in magnetostrictive-piezoelectric laminated composites
Authors: Liu Guoxi , Zhang Chunli , Chen Weiqiu , Dong Shuxiang
Published: July 2013

An analytical model of resonant magnetoelectric (ME) coupling in magnetostrictive (MS)-piezoelectric (PE) laminated composites in consideration of eddy-current effect in MS layer using equivalent circuit method is presented. Numerical calculations show that: (1) the eddy-current has a strong effect on ME coupling in MS-PE laminated composites at resonant frequency; and (2) the resonant ME coupling is then significantly dependent on the sizes of ME laminated composites, which were neglected in most previous theoretical analyses. The achieved results provide a theoretical guidance for the practice engineering design, manufacture, and application of ME laminated composites and devices.
Improvement in piezoelectric strain of annealed Ba(Zr0.07Ti0.93)O3 based ceramics
Authors: Jarupoom Parkpoom , Rujijanagul Gobwute
Published: July 2013

In the present work, effects of annealing time on strain behavior, densification, and microstructure of 2 wt. % B2O3 doped Ba(Zr0.07Ti0.93)O3 ceramics were investigated. The ceramics were initially sintered at 1150 to 1275 °C for 2 h. After sintering, the densest ceramics (1250 °C ceramics) were selected for annealing at 1000 °C for 4-16 h. An increase in strain level and piezoelectric coefficient was observed after some annealing. High bipolar strain level of 0 .48% and high piezoelectric coefficients (d*33) of 603 pm/V were obtained for the 8 h samples. Longer annealing times (>8 h) resulted in reduction of the strain level and piezoelectric value. The change in piezoelectric properties was correlated with the densification and microstructure of the studied samples.
Femur-mounted navigation system for the arthroscopic treatment of femoroacetabular impingement
Authors: Park S. H. , Hwang D. S. , Yoon Y. S.
Published: July 2013

Femoroacetabular impingement stems from an abnormal shape of the acetabulum and proximal femur. It is treated by resection of damaged soft tissue and by the shaping of bone to resemble normal features. The arthroscopic treatment of femoroacetabular impingement has many advantages, including minimal incisions, rapid recovery, and less pain. However, in some cases, revision is needed owing to the insufficient resection of damaged bone from a misreading of the surgical site. The limited view of arthroscopy is the major reason for the complications. In this research, a navigation method for the arthroscopic treatment of femoroacetabular impingement is developed. The proposed navigation system consists of femur attachable measurement device and user interface. The bone mounted measurement devices measure points on head-neck junction for registration and position of surgical instrument. User interface shows the three-dimensional model of patient's femur and surgical instrument position that is tracked by measurement device. Surgeon can know the three-dimensional anatomical structure of hip joint and surgical instrument position on surgical site using navigation system. Surface registration was used to obtain relation between patient's coordinate at the surgical site and coordinate of three-dimensional model of femur. In this research, we evaluated the proposed navigation system using plastic model bone. It is expected that the surgical tool tracking position accuracy will be less than 1 mm.
Coherent photon interference elimination and spectral correction in femtosecond time-resolved fluorescence non-collinear optical parametric amplification spectroscopy
Authors: Dang Wei , Mao Pengcheng , Weng Yuxiang
Published: July 2013

We report an improved setup of femtosecond time-resolved fluorescence non-collinear optical parametric amplification spectroscopy (FNOPAS) with a 210 fs temporal response. The system employs a Cassegrain objective to collect and focus fluorescence photons, which eliminates the interference from the coherent photons in the fluorescence amplification by temporal separation of the coherent photons and the fluorescence photons. The gain factor of the Cassegrain objective-assisted FNOPAS is characterized as 1.24 × 105 for Rhodamine 6G. Spectral corrections have been performed on the transient fluorescence spectra of Rhodamine 6G and Rhodamine 640 in ethanol by using an intrinsic calibration curve derived from the spectrum of superfluorescence, which is generated from the amplification of the vacuum quantum noise. The validity of spectral correction is illustrated by comparisons of spectral shape and peak wavelength between the corrected transient fluorescence spectra of these two dyes acquired by FNOPAS and their corresponding standard reference spectra collected by the commercial streak camera. The transient fluorescence spectra of the Rhodamine 6G were acquired in an optimized phase match condition, which gives a deviation in the peak wavelength between the retrieved spectrum and the reference spectrum of 1.0 nm, while those of Rhodamine 640 were collected in a non-optimized phase match condition, leading to a deviation in a range of 1.0–3.0 nm. Our results indicate that the improved FNOPAS can be a reliable tool in the measurement of transient fluorescence spectrum for its high temporal resolution and faithfully corrected spectrum.
Laser-induced breakdown spectroscopy of tantalum plasma
Authors: Khan Sidra , Bashir Shazia , Hayat Asma , Khaleeq-ur-Rahman M. , Faizan–ul-Haq
Published: July 2013

Laser Induced Breakdown spectroscopy (LIBS) of Tantalum (Ta) plasma has been investigated. For this purpose Q-switched Nd: YAG laser pulses (λ ∼ 1064 nm, τ ∼ 10 ns) of maximum pulse energy of 100 mJ have been employed as an ablation source. Ta targets were exposed under the ambient environment of various gases of Ar, mixture (CO2: N2: He), O2, N2, and He under various filling pressure. The emission spectrum of Ta is observed by using LIBS spectrometer. The emission intensity, excitation temperature, and electron number density of Ta plasma have been evaluated as a function of pressure for various gases. Our experimental results reveal that the optical emission intensity, the electron temperature and density are strongly dependent upon the nature and pressure of ambient environment. The SEM analysis of the ablated Ta target has also been carried out to explore the effect of ambient environment on the laser induced grown structures. The growth of grain like structures in case of molecular gases and cone-formation in case of inert gases is observed. The evaluated plasma parameters by LIBS analysis such as electron temperature and the electron density are well correlated with the surface modification of laser irradiated Ta revealed by SEM analysis.
Predicting phase behavior in multicomponent mixtures
Authors: Jacobs William M. , Frenkel Daan
Published: July 2013

Mixtures with a large number of components can undergo phase transitions of a hybrid character, with both condensation and demixing contributions. We describe a robust Monte Carlo simulation method for calculating phase coexistence in multicomponent mixtures. We use this approach to study the phase behavior of lattice models of multicomponent mixtures with strongly varying pair interactions. Such a system can be thought of as a simplified model of the cytosol, with both specific and nonspecific interactions. We show that mapping a multicomponent mixture onto an approximately equivalent one-component system yields both upper and lower bounds on the maximum solute volume fraction of a stable, homogeneous phase. By following the minimum excess-free-energy path from the dilute phase free-energy minimum, we predict the difference in composition between the condensed and dilute phases at the boundary of the homogeneous phase. We find that this “direction” of phase separation rarely aligns with the dominant direction of density fluctuations in the dilute phase. We also show that demixing transitions tend to lower the maximum solute volume fraction at which the homogeneous phase is stable. By considering statistical ensembles of mixtures with random interactions, we show that the demixing contribution to phase separation is self-averaging and dependent only on the mean and variance of the distribution of interactions.
Structures, electrophilic properties, and hydrogen bonds of cytidine, uridine, and their radical anions: Microhydration effects
Authors: Shao Peng , Kuang Xiao-Yu , Ding Li-Ping , Zhao Ya-Ru
Published: July 2013

Structures, electrophilic properties, and hydrogen bonds of the neutral and anionic monohydrated nucleoside, (cytidine)H2O, and (uridine)H2O have been systematically investigated using density functional theory. Various water-binding sites were predicted by explicitly considering the optimized monohydrated structures. Meanwhile, predictions of electron affinities and vertical detachment energies were also carried out to investigate their electrophilic properties. By examining the singly occupied molecular orbital and natural population analysis, we found the excess negative charge is localized on the cytidine and uridine moiety in anionic monohydrates. This may be the reason why the strength of hydrogen bonding undergoes an obvious change upon the extra electron attachment. Based on the electron density (ρ) and reduced density gradient (RDG), we present an approach to map and analyze the weak interaction (especially hydrogen bond) in monohydrated cytidine and uridine. The scatter plots of RDG versus ρ allow us to identify the different type interactions. Meanwhile, the maps of the gradient isosurfaces show a rich visualization of hydrogen bond, van der Waals interaction, and steric effect.
Using the uncertainty principle to design simple interactions for targeted self-assembly
Authors: Edlund E. , Lindgren O. , Jacobi M. Nilsson
Published: July 2013

We present a method that systematically simplifies isotropic interactions designed for targeted self-assembly. The uncertainty principle is used to show that an optimal simplification is achieved by a combination of heat kernel smoothing and Gaussian screening of the interaction potential in real and reciprocal space. We use this method to analytically design isotropic interactions for self-assembly of complex lattices and of materials with functional properties. The derived interactions are simple enough to narrow the gap between theory and experimental implementation of theory based designed self-assembling materials.
Simplified confocal microscope for counting particles at low concentrations
Authors: Skinner Joseph P. , Swift Kerry M. , Ruan Qiaoqiao , Perfetto Sergio , Gratton Enrico , Tetin Sergey Y.
Published: July 2013

We describe a compact scanning confocal fluorescence microscope capable of detecting particles concentrations less than 100 particles/ml in ∼15 min. The system mechanically moves a cuvette containing ∼3 ml of sample. A relatively large confocal volume is observed within the cuvette using a 1 mm pinhole in front of a detection PMT. Due to the motion of the sample, particles traverse the confocal volume quickly, and analysis by pattern recognition qualifies spikes in the emission intensity data and counts them as events. We show linearity of detection as a function of concentration and also characterize statistical behavior of the instrument. We calculate a detection sensitivity of the system using 3 μm fluorescent microspheres to be 5 particles/ml. Furthermore, to demonstrate biological application, we performed a dilution series to quantify stained E. coli and yeast cells. We counted E. coli cells at a concentration as low as 30 cells/ml in 10 min/sample.
Noise reduction in functional near-infrared spectroscopy signals by independent component analysis
Authors: Santosa Hendrik , Jiyoun Hong Melissa , Kim Sung-Phil , Hong Keum-Shik
Published: July 2013

Functional near-infrared spectroscopy (fNIRS) is used to detect concentration changes of oxy-hemoglobin and deoxy-hemoglobin in the human brain. The main difficulty entailed in the analysis of fNIRS signals is the fact that the hemodynamic response to a specific neuronal activation is contaminated by physiological and instrument noises, motion artifacts, and other interferences. This paper proposes independent component analysis (ICA) as a means of identifying the original hemodynamic response in the presence of noises. The original hemodynamic response was reconstructed using the primary independent component (IC) and other, less-weighting-coefficient ICs. In order to generate experimental brain stimuli, arithmetic tasks were administered to eight volunteer subjects. The t-value of the reconstructed hemodynamic response was improved by using the ICs found in the measured data. The best t-value out of 16 low-pass-filtered signals was 37, and that of the reconstructed one was 51. Also, the average t-value of the eight subjects’ reconstructed signals was 40, whereas that of all of their low-pass-filtered signals was only 20. Overall, the results showed the applicability of the ICA-based method to noise-contamination reduction in brain mapping.
Subdiffusive transport of fluctuating elastic filaments in cellular flows
Authors: Manikantan Harishankar , Saintillan David
Published: July 2013

The dynamics and transport properties of Brownian semiflexible filaments suspended in a two-dimensional array of counter-rotating Taylor-Green vortices are investigated using numerical simulations based on slender-body theory for low-Reynolds-number hydrodynamics. Such a flow setup has been previously proposed to capture some of the dynamics of biological polymers in motility assays. A buckling instability permits elastic filaments to migrate across such a cellular lattice in a “Brownian-like” manner even in the athermal limit. However, thermal fluctuations alter these dynamics qualitatively by driving polymers across streamlines, leading to their frequent trapping within vortical cells. As a result, thermal fluctuations, characterized here by the persistence length, are shown to lead to subdiffusive transport at long times, and this qualitative shift in behavior is substantiated by the slow decay of waiting-time distributions as a consequence of trapping events during which the filaments remain in a particular cell for extended periods of time. Velocity and mass distributions of polymers reveal statistically preferred positions within a unit cell that further corroborate this systematic shift from transport to trapping with increasing fluctuations. Comparisons to results from a continuum model for the complementary case of rigid Brownian rods in such a flow also highlight the role of elastic flexibility in dictating the nature of polymer transport.
Rigid-body rotation of an electron cloud in divergent magnetic fields
Authors: Fruchtman A. , Gueroult R. , Fisch N. J.
Published: July 2013

For a given voltage across a divergent poloidal magnetic field, two electric potential distributions, each supported by a rigid-rotor electron cloud rotating with a different frequency, are found analytically. The two rotation frequencies correspond to the slow and fast rotation frequencies known in uniform plasma. Due to the centrifugal force, the equipotential surfaces, that correspond to the two electric potential distributions, diverge more than the magnetic surfaces do, the equipotential surfaces in the fast mode diverge largely in particular. The departure of the equipotential surfaces from the magnetic field surfaces may have a significant focusing effect on the ions accelerated by the electric field. The focusing effect could be important for laboratory plasma accelerators as well as for collimation of astrophysical jets.
Anomalous structural evolution in Cu50Zr50 glass-forming liquids
Authors: Mauro Nicholas A. , Vogt Adam J. , Johnson Mark L. , Bendert James C. , Kelton Kenneth F.
Published: July 2013

The structural evolution of the Cu50Zr50 liquid and glass was determined from in situ high-energy X-ray diffraction measurements. The temperature dependence of the static X-ray structure factor for the glass was measured from room temperature to above the glass transition temperature. Data were obtained for equilibrium and supercooled liquids in a containerless environment using electrostatic levitation. The structure factors and the total pair correlation functions display an anomalous evolution, indicating a rapid acceleration of short-range atomic order in the liquid above, but near the glass transition temperature. This behavior contrasts sharply with that observed in high glass forming ability metallic liquids.
Communication: Vibrational spectroscopy of Au4 from high resolution photoelectron imaging
Authors: Yang Zheng , Leon Iker , Wang Lai-Sheng
Published: July 2013

High resolution photoelectron spectroscopy of Au4− is reported using a new photoelectron imaging apparatus. A broad vibrational progression is resolved for the detachment transition from the ground electronic state of the Y-shaped Au4− to that of the Y-shaped Au4 neutral (C2v, 1A1) in the ν2 vibrational mode with a harmonic frequency of 171(7) cm−1 and an anharmonicity of ∼0.5 cm−1. In addition, two low frequency modes with weak Franck-Condon factors are observed: the v3 mode with a frequency of 97(7) cm−1 and the v6 mode with a frequency of 17(7) cm−1. An accurate electron affinity of 2.7098(6) eV is obtained for the Y-shaped Au4 neutral cluster. The current study shows that very low frequency vibrational modes can be resolved for size-selected clusters using high resolution photoelectron imaging, providing valuable additional experimental information for cluster structure determination.
Pump-beam-induced optical damage depended on repetition frequency and pulse width in 4-dimethylamino-N ′-methyl-4′-stilbazolium tosylate crystal
Authors: Matsukawa Takeshi , Nawata Kouji , Notake Takashi , Qi Feng , Kawamata Hiroshi , Minamide Hiroaki
Published: July 2013

We investigated the dependence of optical damage to an organic nonlinear optical crystal of 4-dimethylamino-N′-methyl-4′-stilbazolium tosylate (DAST) on the repetition frequency and pulse width of the pump beam used to cause the thermal damage. For a pump beam with a pulse width of 15 ns at a wavelength of 1064 nm, the highest damage threshold of 8.0 J/cm2 was measured for repetition frequencies in the range from 10 to 40 Hz. On the other hand, DAST crystals were easily damaged under the repetition rates from 50 to 100 Hz. For 600-ps pulses, a higher damage threshold that was a factor of 11 to 28 times higher in terms of peak intensity was obtained compared with that of 15-ns pulses. In both the cases of 15-ns pulse duration and 600-ps duration, we demonstrated that the thermal effects in DAST crystals dominated the optical damage, which depended on thermal accumulation and dissipation.
Efficient and stable laser-driven white lighting
Authors: Denault Kristin A. , Cantore Michael , Nakamura Shuji , DenBaars Steven P. , Seshadri Ram
Published: July 2013

Laser-based white lighting offers a viable option as an efficient and color-stable high-power solid-state white light source. We show that white light generation is possible using blue or near-UV laser diodes in combination with yellow-emitting cerium-substituted yttrium aluminum garnet (YAG:Ce) or a mixture of red-, green-, and blue-emitting phosphors. A variety of correlated color temperatures (CCT) are achieved, ranging from cool white light with a CCT of 4400 K using a blue laser diode to a warm white light with a CCT of 2700 K using a near-UV laser diode, with respective color rendering indices of 57 and 95. The luminous flux of these devices are measured to be 252 lm and 53 lm with luminous efficacies of 76 lm/W and 19 lm/W, respectively. An estimation of the maximum efficacy of a device comprising a blue laser diode in combination with YAG:Ce is calculated and the results are used to optimize the device.
The influence of the spin-orbit torques on the current-driven domain wall motion
Authors: Martinez Eduardo , Finocchio Giovanni , Torres Luis , Lopez-Diaz Luis
Published: July 2013

The current-induced domain wall motion along a ferromagnetic strip with high perpendicular magnetocristalline anisotropy sandwiched in an multilayer stack is theoretically studied, by means of micromagnetic simulations and the one-dimensional model, with emphasis on the roles of the Rashba spin-orbit coupling and the spin Hall effect. The results point out that in the presence of a strong Rashba field the domain wall motion can be either in the direction of the current or opposing to it depending on the amplitude of the spin Hall effect. The predictions are in agreement with the experiments only in a reduced range of positive spin Hall angles under a strong Rashba torque.
Creating the Cicerone Project: seeking closer engagement between livestock producers, research and extension
Authors: Sutherland H. , Scott J. M. , Gray G. D. , Woolaston R. R.
Published: July 2013

A unique project led by livestock producers, called the Cicerone Project, was undertaken on the Northern Tablelands region of New South Wales, Australia, following acknowledgement by those producers of a widening gap between them and research and extension information. The overall aim of the project was to co-learn, through a partnership between livestock producers, research, extension and other specialists, how to improve the profitability and sustainability of grazing enterprises in that region. It was hypothesised that closer engagement would help to guide relevant research efforts and also enhance the adoption of research findings. With the support of industry funding and the collaboration of key research, education and extension partners, the inaugural steering committee of the Cicerone Project commissioned a survey of over 300 land managers in the region to explore their research and adoption needs. The survey identified the most important issues and found a high level of commitment to the formation of this producer-led project. Negotiations between all collaborators led to the creation of a Business Plan prepared as the basis for an initial funding period of 5 years. Subsequent reviews of the project allowed for extensions with associated activities over an additional 4 years. In order to study the key farm management alternatives identified from the producer survey, the Cicerone Project Board decided to adopt an agricultural ecosystem approach which conducted studies using three whole-farmlet systems. The farmlet experiment compared three contiguous farmlets by measuring as many aspects of the farm systems as possible using an approach summarised in the motto adopted by the Cicerone Project of ‘compare–measure–learn–adopt’. A wide range of field days and seminars were held over the duration of the project to deliver the results to the producer members. This paper provides an introduction to a Special Issue containing 24 papers which report on the entirety of the project from planning, to execution, results, and reflections on the value obtained from the many research and extension activities, with particular emphasis on the farming systems trial conducted between 2000 and 2006.
Simulating the impact of fertiliser strategies and prices on the economics of developing and managing the Cicerone Project farmlets under climatic uncertainty
Authors: Behrendt Karl , Scott James M. , Cacho Oscar , Jones Randall
Published: July 2013

The application of fertilisers to pastures in the high rainfall regions of southern Australia has contributed to large increases in carrying capacity following the widespread adoption of the practice since the late 1940s. Recently, large shifts in the worldwide demand for fertiliser inputs have lead to large rises in the cost of fertiliser inputs. These increasing costs have significant potential ramifications on the future management of soil fertility and its interaction with the persistence and profitability of sown pastures, especially during periods of climatic uncertainty. A dynamic pasture resource development simulation model was used to investigate the implications of fertiliser rates and costs on the efficient management of soil fertility under climatic uncertainty. The framework also allowed the investigation of how the management of soil fertility interacts with the utilisation of pasture resources through different stocking rates. In the application of this method to the Cicerone Project farmlets case study, fertiliser input costs were found to influence the optimal combination of fertiliser inputs and stocking rate. Analyses of the dynamic interaction between fertiliser application and cost, stocking rate and the persistence of desirable species enabled the identification of the most risk-efficient strategies. The implications for grazing industries in the high rainfall regions of southern Australia are discussed.
Optimising pasture and grazing management decisions on the Cicerone Project farmlets over variable time horizons
Authors: Behrendt Karl , Cacho Oscar , Scott James M. , Jones Randall
Published: July 2013

This study addresses the problem of balancing the trade-offs between the need for animal production, profit, and the goal of achieving persistence of desirable species within grazing systems. The bioeconomic framework applied in this study takes into account the impact of climate risk and the management of pastures and grazing rules on the botanical composition of the pasture resource, a factor that impacts on livestock production and economic returns over time. The framework establishes the links between inputs, the state of the pasture resource and outputs, to identify optimal pasture development strategies. The analysis is based on the application of a dynamic pasture resource development simulation model within a seasonal stochastic dynamic programming framework. This enables the derivation of optimum decisions within complex grazing enterprises, over both short-term tactical (such as grazing rest) and long-term strategic (such as pasture renovation) time frames and under climatic uncertainty. The simulation model is parameterised using data and systems from the Cicerone Project farmlet experiment. Results indicate that the strategic decision of pasture renovation should only be considered when pastures are in a severely degraded state, whereas the tactical use of grazing rest or low stocking rates should be considered as the most profitable means of maintaining adequate proportions of desirable species within a pasture sward. The optimal stocking rates identified reflected a pattern which may best be described as a seasonal saving and consumption cycle. The optimal tactical and strategic decisions at different pasture states, based on biomass and species composition, varies both between seasons and in response to the imposed soil fertility regime. Implications of these findings at the whole-farm level are discussed in the context of the Cicerone Project farmlets.
Satellite derived evidence of whole farmlet and paddock responses to management and climate
Authors: Donald G. E. , Scott J. M. , Vickery P. J.
Published: July 2013

Satellite imagery was used to assess differences between three treatments in a grazing enterprise systems study of three 53-ha farmlets on the Northern Tablelands of New South Wales, Australia. The study involved a comparison between a typical control farmlet (B) with one with higher levels of sown pasture and soil fertility (A) and one employing intensive rotational grazing (C). Landsat thematic mapper data were used to derive normalised difference vegetation index (NDVI) and spectral class images for eight dates from before the commencement of the farmlet trial (June 2000) to annual spring measurements in September–October of each year from 2000 to 2006 across all paddocks of each farmlet. The Landsat imagery taken before the commencement of the farmlet treatments (June 2000) showed only small differences between the three farmlets, confirming that the allocation of land to the farmlets had been without bias. The assessments using Landsat NDVI in spring over 7 years showed differences in green herbage resulting from the variation in rainfall received over different years as well as differences between the farmlets. The Landsat NDVI images showed increasing and significant differences in pasture greenness over time, especially between Farmlet A and Farmlets B and C. In addition, there were significant differences in pasture spectral classes between Farmlet A and Farmlets B and C, with a significant correlation with higher levels of sown perennial and annual grasses and legumes on Farmlet A. Using different statistical tools, several relationships were found between NDVI and spectral class data and explanatory variables of farmlet, paddock, sowing phase, modelled soil moisture and recent grazing activity. The moderate resolution Landsat data across the entire area of each farmlet proved to be especially useful for assessing pastures within every paddock used in this farmlet study. In addition, moderate resolution imaging spectro radiometer NDVI satellite data were collated for weekly intervals from September 2003 to December 2006 in order to assess seasonal pasture growth patterns on each of the farmlets. These patterns were significantly correlated with a growth index calculated from temperature and available soil moisture, and showed that the growth on the three farmlets was closer to a highly productive reference paddock than a low input, unsown pasture in another reference paddock. The satellite data facilitated the detection of significant differences in pasture botanical composition, soil fertility, grazing management, climate and season. The ready availability of quality remote sensed imagery, combined with the significance of the relationships established, confirms that the technology is a valuable objective tool for both farming systems research and for managing entire farms.