bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation of switching loss and current total harmonic distortion of cascaded multilevel grid‐connected inverter and Europe efficiency enhancement considering variation of DC source power
Authors: Wu Fengjiang , Li Boyang , Duan Jiandong
Published: September 2015

Efficiency improvement has become a hot topic in grid‐connected inverters (GCI). In single‐phase single‐stage cascaded multilevel GCIs (CM‐GCI), the level number of the inverter output voltage will change with the variation of the DC supply source generation power. This results in significant changes of switching losses and changes in the total harmonics distortion (THD) of the grid current. In this study, the switching losses and the current THD of CM‐GCI are derived under variable DC voltage. The theoretical analysis indicates that switching losses will increase with increasing DC voltage while the current THD will be reduced. Furthermore, on the basis of the derived expression of the current THD and taking the special grid current THD standards as design criteria conditions, an European efficiency enhancement scheme with adjusting carrier frequency in real time is proposed. Detailed experimental results including the constant and variable carrier frequency schemes are given and compared with each other to verify the accuracy of the theoretical analysis results and the validity of the proposed efficiency enhancement scheme.
A family of wave-breaking equations generalizing the Camassa-Holm and Novikov equations
Authors: Anco Stephen C. , da Silva Priscila Leal , Freire Igor Leite
Published: September 2015

A 4-parameter polynomial family of equations generalizing the Camassa-Holm and Novikov equations that describe breaking waves is introduced. A classification of low-order conservation laws, peaked travelling wave solutions, and Lie symmetries is presented for this family. These classifications pick out a 1-parameter equation that has several interesting features: it reduces to the Camassa-Holm and Novikov equations when the polynomial has degree two and three; it has a conserved H1 norm and it possesses N-peakon solutions when the polynomial has any degree; and it exhibits wave-breaking for certain solutions describing collisions between peakons and anti-peakons in the case N = 2.
Finite-temperature coupled-cluster, many-body perturbation, and restricted and unrestricted Hartree–Fock study on one-dimensional solids: Luttinger liquids, Peierls transitions, and spin- and charge-density waves
Authors: Hermes Matthew R. , Hirata So
Published: September 2015

One-dimensional (1D) solids exhibit a number of striking electronic structures including charge-density wave (CDW) and spin-density wave (SDW). Also, the Peierls theorem states that at zero temperature, a 1D system predicted by simple band theory to be a metal will spontaneously dimerize and open a finite fundamental bandgap, while at higher temperatures, it will assume the equidistant geometry with zero bandgap (a Peierls transition). We computationally study these unique electronic structures and transition in polyyne and all-trans polyacetylene using finite-temperature generalizations of ab initio spin-unrestricted Hartree–Fock (UHF) and spin-restricted coupled-cluster doubles (CCD) theories, extending upon previous work [He et al., J. Chem. Phys. 140, 024702 (2014)] that is based on spin-restricted Hartree–Fock (RHF) and second-order many-body perturbation (MP2) theories. Unlike RHF, UHF can predict SDW as well as CDW and metallic states, and unlike MP2, CCD does not diverge even if the underlying RHF reference wave function is metallic. UHF predicts a gapped SDW state with no dimerization at low temperatures, which gradually becomes metallic as the temperature is raised. CCD, meanwhile, confirms that electron correlation lowers the Peierls transition temperature. Furthermore, we show that the results from all theories for both polymers are subject to a unified interpretation in terms of the UHF solutions to the Hubbard–Peierls model using different values of the electron-electron interaction strength, U/t, in its Hamiltonian. The CCD wave function is shown to encompass the form of the exact solution of the Tomonaga–Luttinger model and is thus expected to describe accurately the electronic structure of Luttinger liquids.
Hydrogen adsorption induced antiferrodistortive distortion and metallization at the (001) surface of SrTiO3
Authors: Yang Yi , Lin Chen-Sheng , Cheng Wen-Dan
Published: September 2015

SrTiO3 (STO) is attracting lots of research interests due to the rich physics and properties presented at its surfaces and the interfaces of STO with other transition metal oxides. Based on density functional theory methods, we have investigated the influence of hydrogen (H) atoms adsorption at the (001) surface of STO on the geometrical and electronic structures of the surface. We find that H adsorption induces significant antiferrodistortive (AFD) distortion of TiO6 octahedra at the surface. By calculating H adsorption energy, we show that AFD distortion makes a significant contribution to the stability of H adsorbed STO surfaces. The calculated energy position of O-H bond states by hybrid functional method is 9.9 eV below Fermi level, in agreement with experimental value of 10 eV. The electrons donated by H atoms first occupy several dxy bands and then start to fill in degenerate dyz/dxz bands, indicating the metallization of initially insulating STO. The band splitting and occupy sequence calculated here are consistent with recent angle-resolved photoemission spectroscopy experiments. Our results reveal that H adsorption changes the atomic and electronic structures and thus induce fascinating properties at the surface of STO.
Ab initio determination of the elastic properties of ferromagnetic body-centered cubic Fe-Mn-Al alloys
Authors: Zhang Hualei , Lu Song , Zhou Minna , Punkkinen Marko P. J. , Johansson Börje , Vitos Levente
Published: September 2015

The elastic properties of ferromagnetic Fe1−x−yMnyAlx (0 ≤ x ≤ 0.5, y = 0, 0.1, and 0.2) random solid solutions in the body-centered cubic (bcc) crystallographic phase have been investigated using the ab initio exact muffin-tin orbitals method in combination with the coherent-potential approximation. Comparison with the experimental data demonstrates that the employed theoretical approach accurately captures the observed composition dependence of the lattice parameter. The predicted elastic parameters follow complex composition dependence. The C11, C12, and C′ = (C11 − C12)/2 single-crystal elastic constants, the bulk (B), shear (G), and Young's (E) moduli, and the Cauchy pressure (C12 − C44) mainly decrease with increasing Al content, whereas the Zener anisotropy ratio (C44/C′) strongly increases with x. C44 exhibits a non-linear x dependence. The Poisson (v) and Pugh (B/G) ratios first decrease with x but show non-monotonous behavior in high-Al alloys. In terms of the Pugh criterion, these trends suggest an increased brittleness in Al-containing alloys. Manganese has a complex non-monotonous effect on B/G in low-Al alloys (below ∼15 at. % Al) but enhances the brittleness of the bcc solid solution in large-Al regime. The peculiar Mn alloying effect is explained in terms of magneto-volume mechanisms.
Unified Bohm criterion
Authors: Kos L. , Tskhakaya D. D. , Jelić N.
Published: September 2015

Recent decades have seen research into the conditions necessary for the formation of the monotonic potential shape in the sheath, appearing at the plasma boundaries like walls, in fluid, and kinetic approximations separately. Although either of these approaches yields a formulation commonly known as the much-acclaimed Bohm criterion (BC), the respective results involve essentially different physical quantities that describe the ion gas behavior. In the fluid approach, such a quantity is clearly identified as the ion directional velocity. In the kinetic approach, the ion behavior is formulated via a quantity (the squared inverse velocity averaged by the ion distribution function) without any clear physical significance, which is, moreover, impractical. In the present paper, we try to explain this difference by deriving a condition called here the Unified Bohm Criterion, which combines an advanced fluid model with an upgraded explicit kinetic formula in a new form of the BC. By introducing a generalized polytropic coefficient function, the unified BC can be interpreted in a form that holds, irrespective of whether the ions are described kinetically or in the fluid approximation.
Trapping of intense light in hollow shell
Authors: Luan Shixia , Yu Wei , Yu M. Y. , Weng Suming , Wang Jingwei , Xu Han , Zhuo Hongbin , Wong A. Y.
Published: September 2015

A small hollow shell for trapping laser light is proposed. Two-dimensional particle-in-cell simulation shows that under appropriate laser and plasma conditions a part of the radiation fields of an intense short laser pulse can enter the cavity of a small shell through an over-critical density plasma in an adjacent guide channel and become trapped. The trapped light evolves into a circulating radial wave pattern until its energy is dissipated.
Layer-transferred MoS2/GaN PN diodes
Authors: Lee Edwin W. , Lee Choong Hee , Paul Pran K. , Ma Lu , McCulloch William D. , Krishnamoorthy Sriram , Wu Yiying , Arehart Aaron R. , Rajan Siddharth
Published: September 2015

Electrical and optical characterization of two-dimensional/three-dimensional (2D/3D) p-molybdenum disulfide/n-gallium nitride (p-MoS2/n-GaN) heterojunction diodes are reported. Devices were fabricated on high-quality, large-area p-MoS2 grown by chemical vapor deposition on sapphire substrates. The processed devices were transferred onto GaN/sapphire substrates, and the transferred films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). On-axis XRD spectra and surface topology obtained from AFM scans were consistent with previously grown high-quality, continuous MoS2 films. Current-voltage measurements of these diodes exhibited excellent rectification, and capacitance-voltage measurements were used to extract a conduction band offset of 0.23 eV for the transferred MoS2/GaN heterojunction. This conduction band offset was confirmed by internal photoemission measurements. The energy band lineup of the MoS2/GaN heterojunction is proposed here. This work demonstrates the potential of 2D/3D heterojunctions for novel device applications.
Preliminary experimental investigation of a Ku-band radial line oscillator based on transition radiation effect
Authors: Dang Fangchao , Zhang Xiaoping , Zhong Huihuang , Li Yangmei
Published: September 2015

A Ku-band radial line oscillator (RLO) with low guiding magnetic field was proposed in our previous work. In order to weaken the impedance mismatch between the oscillator and an intense electron accelerator with higher impedance, a transverse electromagnetic reflector is added to improve the RLO, which is favorable to increase the Q-factor and accelerate the device saturation. A preliminary experiment is carried out to investigate the performance of the improved RLO. The radial-radiated electron beam is restrained well under the designed guiding magnetic field of 0.52 T. The preliminary experimental results indicates that high power microwaves with a power of 120 MW and a frequency of 14.12 GHz are generated when the diode voltage is 420 kV and the beam current 14.2 kA. The experimental results suggest the feasibility of the presented RLO generating high power microwaves at a high frequency band. Additionally, more work is needed regarding promotion of the electron beam quality and the impedance match between the electron beam accelerator and the oscillator.
Ab initio phase diagram of BaTiO3 under epitaxial strain revisited
Authors: Grünebohm Anna , Marathe Madhura , Ederer Claude
Published: September 2015

We revisit the phase diagram of BaTiO3 under biaxial strain using a first principles-based effective Hamiltonian approach. We show that, in addition to the tetragonal (c), quasi-rhombohedral (r), and quasi-orthorhombic (aa) ferroelectric phases that have been discussed previously, there are temperature and strain regions, in particular, under tensile strain, where the system decomposes into multi-domain structures. In such cases, the strained system, at least on a local level, recovers the same phase sequence as the unclamped bulk material. Furthermore, we extend these results from the case of “uniform” biaxial strain to the situation where the two in-plane lattice constants are strained differently and show that similar considerations apply in this case.
Nonlinear multi-analysis of agent-based financial market dynamics by epidemic system
Authors: Lu Yunfan , Wang Jun , Niu Hongli
Published: September 2015

Based on the epidemic dynamical system, we construct a new agent-based financial time series model. In order to check and testify its rationality, we compare the statistical properties of the time series model with the real stock market indices, Shanghai Stock Exchange Composite Index and Shenzhen Stock Exchange Component Index. For analyzing the statistical properties, we combine the multi-parameter analysis with the tail distribution analysis, the modified rescaled range analysis, and the multifractal detrended fluctuation analysis. For a better perspective, the three-dimensional diagrams are used to present the analysis results. The empirical research in this paper indicates that the long-range dependence property and the multifractal phenomenon exist in the real returns and the proposed model. Therefore, the new agent-based financial model can recurrence some important features of real stock markets.
Resonant tunneling properties of SiO2/polycrystalline Si/SiO2 multilayers fabricated by radio-frequency magnetron sputtering
Authors: Ikuno Takashi , Ogawa Syunsuke , Suzuki Noritomo , Ito Tadashi , Sugimoto Noriaki , Takeda Yasuhiko , Motohiro Tomoyoshi , Higuchi Kazuo
Published: September 2015

SiO2/poly-Si/SiO2 double-barrier structures fabricated by radio-frequency magnetron sputtering are shown to exhibit negative differential resistance (NDR) that is attributed to resonant tunneling (RT) at low temperatures. An annealing process conducted after the multilayer deposition is found to effectively yield stable NDR. Five percent of all of the fabricated devices exhibit clear NDR below 50 K. Other devices with the same multilayered structure exhibit staircase-like current–voltage curves caused by the Coulomb blockade (CB) or by interplay between the RT and CB. The requisites of the poly-Si layer microstructures for the realization of stable RT are elucidated.
Modulation of spin transfer torque amplitude in double barrier magnetic tunnel junctions
Authors: Clément P.-Y. , Baraduc C. , Ducruet C. , Vila L. , Chshiev M. , Diény B.
Published: September 2015

Magnetization switching induced by spin transfer torque is used to write magnetic memories (Magnetic Random Access Memory, MRAM) but can be detrimental to the reading process. It would be quite convenient therefore to modulate the efficiency of spin transfer torque. A solution is adding an extra degree of freedom by using double barrier magnetic tunnel junctions with two spin-polarizers, with controllable relative magnetic alignment. We demonstrate, for these structures, that the amplitude of in-plane spin transfer torque on the middle free layer can be efficiently tuned via the magnetic configuration of the electrodes. Using the proposed design could thus pave the way towards more reliable read/write schemes for MRAM. Moreover, our results suggest an intriguing effect associated with the out-of-plane (field-like) spin transfer torque, which has to be further investigated.
Determining the band alignment of TbAs:GaAs and TbAs:In0.53Ga0.47As
Authors: Bomberger Cory C. , Vanderhoef Laura R. , Rahman Abdur , Shah Deesha , Chase D. Bruce , Taylor Antoinette J. , Azad Abul K. , Doty Matthew F. , Zide Joshua M. O.
Published: September 2015

We propose and systematically justify a band structure for TbAs nanoparticles in GaAs and In0.53Ga0.47As host matrices. Fluence-dependent optical-pump terahertz-probe measurements suggest the TbAs nanoparticles have a band gap and provide information on the carrier dynamics, which are determined by the band alignment. Spectrophotometry measurements provide the energy of optical transitions in the nanocomposite systems and reveal a large blue shift in the absorption energy when the host matrix is changed from In0.53Ga0.47As to GaAs. Finally, Hall data provides the approximate Fermi level in each system. From this data, we deduce that the TbAs:GaAs system forms a type I (straddling) heterojunction and the TbAs:In0.53Ga0.47As system forms a type II (staggered) heterojunction.
Polymer lattices as mechanically tunable 3-dimensional photonic crystals operating in the infrared
Authors: Chernow V. F. , Alaeian H. , Dionne J. A. , Greer J. R.
Published: September 2015

Broadly tunable photonic crystals in the near- to mid-infrared region could find use in spectroscopy, non-invasive medical diagnosis, chemical and biological sensing, and military applications, but so far have not been widely realized. We report the fabrication and characterization of three-dimensional tunable photonic crystals composed of polymer nanolattices with an octahedron unit-cell geometry. These photonic crystals exhibit a strong peak in reflection in the mid-infrared that shifts substantially and reversibly with application of compressive uniaxial strain. A strain of ∼40% results in a 2.2 μm wavelength shift in the pseudo-stop band, from 7.3 μm for the as-fabricated nanolattice to 5.1 μm when strained. We found a linear relationship between the overall compressive strain in the photonic crystal and the resulting stopband shift, with a ∼50 nm blueshift in the reflection peak position per percent increase in strain. These results suggest that architected nanolattices can serve as efficient three-dimensional mechanically tunable photonic crystals, providing a foundation for new opto-mechanical components and devices across infrared and possibly visible frequencies.
Wearable non-volatile memory devices based on topological insulator Bi2Se3/Pt fibers
Authors: Zhang Xiaoyan , Wen Fusheng , Xiang Jianyong , Wang Xiaochen , Wang Limin , Hu Wentao , Liu Zhongyuan
Published: September 2015

Pt fibers (15 μm) were coated with topological insulator Bi2Se3 nanoplates via a single mode microwave-assisted synthesis technique. With the Bi2Se3/Pt fibers, flexible memory devices were facilely assembled, and they were demonstrated to exhibit rewritable nonvolatile resistive switching characteristics of low switching voltage (−1.2 V and +0.7 V), high ON/OFF current ratio (106), and good retention (4500 s), showing the potential application in data storage. The resistive switching mechanism was analyzed on the bases of formation and rupture of conductive filaments.
Model of Ni-63 battery with realistic PIN structure
Authors: Munson Charles E. , Arif Muhammad , Streque Jeremy , Belahsene Sofiane , Martinez Anthony , Ramdane Abderrahim , El Gmili Youssef , Salvestrini Jean-Paul , Voss Paul L. , Ougazzaden Abdallah
Published: September 2015

GaN, with its wide bandgap of 3.4 eV, has emerged as an efficient material for designing high-efficiency betavoltaic batteries. An important part of designing efficient betavoltaic batteries involves a good understanding of the full process, from the behavior of the nuclear material and the creation of electron-hole pairs all the way through the collection of photo-generated carriers. This paper presents a detailed model based on Monte Carlo and Silvaco for a GaN-based betavoltaic battery device, modeled after Ni-63 as an energy source. The accuracy of the model is verified by comparing it with experimental values obtained for a GaN-based p-i-n structure under scanning electron microscope illumination.
Polar asymmetry of La(1−δ)Al(1+δ)O3/SrTiO3 heterostructures probed by optical second harmonic generation
Authors: Rubano Andrea , De Luca Gabriele , Schubert Jürgen , Wang Zhe , Zhu Shaobo , Schlom Darrell G. , Marrucci Lorenzo , Paparo Domenico
Published: September 2015

By combining transport measurements and optical second harmonic generation, we have investigated heterostructures formed between crystalline thin films of LaAlO3, with varying stoichiometry and TiO2-terminated SrTiO3(001) substrates. Optical second harmonic generation directly probes the polarity of these heterostructures, thus complementing the transport data. The stoichiometry and the growth temperature are found to be critical parameters for controlling both the interfacial conductivity and the heterostructure polarity. In agreement with the previous work, all of the samples display an insulator-to-metal transition in the Al-reach region, with the conductivity first increasing and then saturating at the highest Al/La ratios. The second harmonic signal also increases as a function of the Al/La ratio, but, at the highest growth temperature, it does not saturate. This unusual behavior is consistent with the formation of an ordered structure of defect dipoles in the LaAlO3 film caused by the off-centering of excess Al atoms in agreement with the theory.
Transport through an impurity tunnel coupled to a Si/SiGe quantum dot
Authors: Foote Ryan H. , Ward Daniel R. , Prance J. R. , Gamble John King , Nielsen Erik , Thorgrimsson Brandur , Savage D. E. , Saraiva A. L. , Friesen Mark , Coppersmith S. N. , Eriksson M. A.
Published: September 2015

Achieving controllable coupling of dopants in silicon is crucial for operating donor-based qubit devices, but it is difficult because of the small size of donor-bound electron wavefunctions. Here, we report the characterization of a quantum dot coupled to a localized electronic state and present evidence of controllable coupling between the quantum dot and the localized state. A set of measurements of transport through the device enable the determination that the most likely location of the localized state is consistent with a location in the quantum well near the edge of the quantum dot. Our results are consistent with a gate-voltage controllable tunnel coupling, which is an important building block for hybrid donor and gate-defined quantum dot devices.
Ag doped silicon nitride nanocomposites for embedded plasmonics
Authors: Bayle M. , Bonafos C. , Benzo P. , Benassayag G. , Pécassou B. , Khomenkova L. , Gourbilleau F. , Carles R.
Published: September 2015

The localized surface plasmon-polariton resonance (LSPR) of noble metal nanoparticles (NPs) is widely exploited for enhanced optical spectroscopies of molecules, nonlinear optics, photothermal therapy, photovoltaics, or more recently in plasmoelectronics and photocatalysis. The LSPR frequency depends not only of the noble metal NP material, shape, and size but also of its environment, i.e., of the embedding matrix. In this paper, Ag-NPs have been fabricated by low energy ion beam synthesis in silicon nitride (SiNx) matrices. By coupling the high refractive index of SiNx to the relevant choice of dielectric thickness in a SiNx/Si bilayer for an optimum antireflective effect, a very sharp plasmonic optical interference is obtained in mid-range of the visible spectrum (2.6 eV). The diffusion barrier property of the host SiNx matrix allows for the introduction of a high amount of Ag and the formation of a high density of Ag-NPs that nucleate during the implantation process. Under specific implantation conditions, in-plane self-organization effects are obtained in this matrix that could be the result of a metastable coarsening regime.
Subwavelength total acoustic absorption with degenerate resonators
Authors: Yang Min , Meng Chong , Fu Caixing , Li Yong , Yang Zhiyu , Sheng Ping
Published: September 2015

We report the experimental realization of perfect sound absorption by sub-wavelength monopole and dipole resonators that exhibit degenerate resonant frequencies. This is achieved through the destructive interference of two resonators' transmission responses, while the matching of their averaged impedances to that of air implies no backscattering, thereby leading to total absorption. Two examples, both using decorated membrane resonators (DMRs) as the basic units, are presented. The first is a flat panel comprising a DMR and a pair of coupled DMRs, while the second one is a ventilated short tube containing a DMR in conjunction with a sidewall DMR backed by a cavity. In both examples, near perfect absorption, up to 99.7%, has been observed with the airborne wavelength up to 1.2 m, which is at least an order of magnitude larger than the composite absorber. Excellent agreement between theory and experiment is obtained.
Study of SiO2/4H-SiC interface nitridation by post-oxidation annealing in pure nitrogen gas
Authors: Chanthaphan Atthawut , Hosoi Takuji , Shimura Takayoshi , Watanabe Heiji
Published: September 2015

An alternative and effective method to perform interface nitridation for 4H-SiC metal-oxide-semiconductor (MOS) devices was developed. We found that the high-temperature post-oxidation annealing (POA) in N2 ambient was beneficial to incorporate a sufficient amount of nitrogen atoms directly into thermal SiO2/SiC interfaces. Although N2-POA was ineffective for samples with thick thermal oxide layers, interface nitridation using N2-POA was achieved under certain conditions, i.e., thin SiO2 layers (< 15 nm) and high annealing temperatures (>1350°C). Electrical characterizations of SiC-MOS capacitors treated with high-temperature N2-POA revealed the same evidence of slow trap passivation and fast trap generation that occurred in NO-treated devices fabricated with the optimized nitridation conditions.
Effect of protein level on growth performance, non-carcass components and carcass characteristics of young sheep from three breeds
Authors: Hajji H. , Smeti S. , Ben Hamouda M. , Atti N.
Published: September 2015

The objective of this study was to evaluate the effect of crude protein (CP) level and breed type on growth, non-carcass components and carcass characteristics of young sheep during the fattening period. Forty-two 1-year-old sheep of the Barbarine (BB), Queue Fine de l’Ouest (QFO) and Noire de Thibar (NT) breeds, with an average weight of 32 kg, were fed diets with two CP levels: 160 and 110 g CP/kg of DM [high protein (HP) and low protein (LP) diet, respectively]. Each breed was divided into two groups and received a daily ration composed of 1 kg of a concentrate (204 and 132 g CP/kg of DM for HP and LP, respectively), and 0.5 kg of oat hay/sheep.day. The trial lasted 120 days after which all of the animals were slaughtered. It was found that protein level had not affected the growth rate, although the slaughter weight was 48.75 and 51.56 kg for groups receiving the LP and HP diets, respectively. Overall, carcass yields, non-carcass components and carcass composition were similar for both CP levels (50%, 18% and 32% of muscle, bone and fat, respectively). However, the HP diet promoted fat depots and the development of third grade fat meat whereas the LP diet enhanced first grade leg and lean meat. The BB breed had a higher dressing percentage and a lower offal percentage than QFO and NT breeds. The QFO breed recorded the heaviest internal fat whereas the NT registered the heaviest internal organs and the highest percentage of leg and shoulder. From the findings it can be concluded that CP requirements for young sheep could be limited to 110 g CP/kg of DM.
Modelling photosynthesis in flag leaves of winter wheat (Triticum aestivum) considering the variation in photosynthesis parameters during development
Authors: Sun Jingsong , Sun Jindong , Feng Zhaozhong
Published: September 2015

The Farquhar–von Caemmerer–Berry (FvCB) model of photosynthesis has been widely used to estimate the photosynthetic C flux of plants under different growth conditions. However, the seasonal fluctuation of some photosynthesis parameters (e.g. the maximum carboxylation rate of Rubisco (Vcmax), the maximum electron transport rate (Jmax) and internal mesophyll conductance to CO2 transport (gm)) is not considered in the FvCB model. In this study, we investigated the patterns of the FvCB parameters during flag leaf development based on measured photosynthesis–intercellular CO2 curves in two cultivars of winter wheat (Triticum aestivum L.). Parameterised seasonal patterns of photosynthesis parameters in the FvCB model have subsequently been applied in order to predict the photosynthesis of flag leaves. The results indicate that the Gaussian curve characterises the dynamic patterns of Vcmax, Jmax and gm well. Compared with the model with fixed photosynthesis parameter values, updating the FvCB model by considering seasonal changes in Vcmax and Jmax during flag leaf development slightly improved predictions of photosynthesis. However, if the updated FvCB model incorporated the seasonal patterns of Vcmax and Jmax, and also of gm, predictions of photosynthesis was improved a lot, matching well with the measurements (R2 = 0.87, P < 0.0001). This suggests that the dynamics of photosynthesis parameters, particularly gm, play an important role in estimating the photosynthesis rate of winter wheat.
Follicle vascularity coordinates corpus luteum blood flow and progesterone production
Authors: de Tarso S. G. S. , Gastal G. D. A. , Bashir S. T. , Gastal M. O. , Apgar G. A. , Gastal E. L.
Published: September 2015

Colour Doppler ultrasonography was used to compare the ability of preovulatory follicle (POF) blood flow and its dimensions to predict the size, blood flow and progesterone production capability of the subsequent corpus luteum (CL). Cows (n = 30) were submitted to a synchronisation protocol. Follicles ≥7 mm were measured and follicular wall blood flow evaluated every 12 h for approximately 3.5 days until ovulation. After ovulation, cows were scanned daily for 8 days and similar parameters were evaluated for the CL. Blood samples were collected and plasma progesterone concentrations quantified. All parameters were positively correlated. Correlation values ranged from 0.26 to 0.74 on data normalised to ovulation and from 0.31 to 0.74 on data normalised to maximum values. Correlations between calculated ratios of both POF and CL in data normalised to ovulation and to maximum values ranged from moderate (0.57) to strong (0.87). Significant (P < 0.0001) linear regression analyses were seen in all comparisons. In conclusion, higher correlations were observed between the dimensions of POF and/or CL and blood flow of both structures, as well as POF and/or CL blood flow with plasma progesterone concentrations of the resultant CL. These findings indicate that follicle vascularity coordinates CL blood flow and progesterone production in synchronised beef cows.
Managing cattle grazing intensity: effects on soil organic matter and soil nitrogen
Authors: Segoli Moran , Bray Steven , Allen Diane , Dalal Ram , Watson Ian , Ash Andrew , O'Reagain Peter
Published: September 2015

Extensive cattle grazing is the dominant land use in northern Australia. It has been suggested that grazing intensity and rainfall have profound effects on the dynamics of soil nutrients in northern Australia’s semi-arid rangelands. Previous studies have found positive, neutral and negative effects of grazing pressure on soil nutrients. These inconsistencies could be due to short-term experiments that do not capture the slow dynamics of some soil nutrients and the effects of interannual variability in rainfall. In a long-term cattle grazing trial in northern Australia on Brown Sodosol–Yellow Kandosol complex, we analysed soil organic matter and mineral nitrogen in surface soils (0–10 cm depth) 11, 12 and 16 years after trial establishment on experimental plots representing moderate stocking (stocked at the long-term carrying capacity for the region) and heavy stocking (stocked at twice the long-term carrying capacity). Higher soil organic matter was found under heavy stocking, although grazing treatment had little effect on mineral and total soil nitrogen. Interannual variability had a large effect on soil mineral nitrogen, but not on soil organic matter, suggesting that soil nitrogen levels observed in this soil complex may be affected by other indirect pathways, such as climate. The effect of interannual variability in rainfall and the effects of other soil types need to be explored further.
Identification and interpretation of sources of uncertainty in soils change in a global systems-based modelling process
Authors: Robinson N. J. , Benke K. K. , Norng S.
Published: September 2015

In the past, uncertainty analysis in soil research was often reduced to consideration of statistical variation in numerical data relating to model parameters, model inputs or field measurements. The simplified conceptual approach used by modellers in calibration studies can be misleading, because it relates mainly to error minimisation in regression analysis and is reductionist in nature. In this study, a large number of added uncertainties are identified in a more comprehensive attention to the problem. Uncertainties in soil analysis include errors in geometry, position and polygon attributes. The impacts of multiple error sources are described, including covariate error, model error and laboratory analytical error. In particular, the distinction is made between statistical variability (aleatory uncertainty) and lack of information (epistemic uncertainty). Examples of experimental uncertainty analysis are provided and discussed, including reference to error disaggregation and geostatistics, and a systems-based analytic framework is proposed. It is concluded that a more comprehensive and global approach to uncertainty analysis is needed, especially in the context of developing a future soils modelling process for incorporation of all known sources of uncertainty.
Shape-designed frustration by local polymorphism in a near-equilibrium colloidal glass
Authors: Zhao Kun , Mason Thomas G.
Published: September 2015

Significance

The origin of disorder in glasses is one of the most important unresolved questions in materials science. In many cases, for materials made of monodisperse components that are not attractive and have the capacity to crystallize, such as dispersions of colloidal hard spheres, the disorder is typically associated with rapid, out-of-equilibrium quenching of the density that causes components to jam into disordered configurations. By contrast, here we reveal that hard colloidal kite-shaped particles, which have the geometric capacity to crystallize, instead form a disordered glass when compressed very slowly and quasi-statically. We show that this glassy disorder results from a high diversity of different local configurations of kites, effectively masking the one global crystal phase.
Quantifying a Manual Triangulation Technique for Aquatic Ultrasonic Telemetry
Authors: Taylor Andrew D. , Litvak Matthew K.
Published: September 2015

Ultrasonic telemetry is widely used to determine the large-scale migrations and movements of aquatic animals, but it can also be used to monitor fine-scale movements and habitat occupancy. We tested the accuracy and precision of a method that manually triangulates transmitter locations from a series of bearings recorded at known observer locations. Bearing estimates were based on the direction of the strongest transmitter pulse received at each stationary position. With a minimum of three bearing estimates, transmitter locations and 95% confidence ellipses were calculated. Testing within a blind experimental design showed that triangulation improved accuracy and precision when additional bearings were used and that it was optimized when bearings were recorded from widespread locations. Using 3–7 bearing positions, 95% of all location estimates were within 34 m of the actual transmitter. Triangulation is best suited for monitoring animals during periods of quiescence, and it can be used effectively to describe the extent of home ranges, spawning areas, and overwintering habitat, among other factors. Understanding the fine-scale habitat occupancy of aquatic animals is critical to species management, and triangulation can provide substantial improvements to the traditional location estimates used in ultrasonic telemetry.

Received December 30, 2014; accepted June 2, 2015
High-performance liquid chromatographic method for profiling 2-oxo acids in urine and its application in evaluating vitamin status in rats
Authors: Shibata Katsumi , Nakata Chifumi , Fukuwatari Tsutomu
Published: September 2015

B-group vitamins are involved in the catabolism of 2-oxo acids. To identify the functional biomarkers of B-group vitamins, we developed a high-performance liquid chromatographic method for profiling 2-oxo acids in urine and applied this method to urine samples from rats deficient in vitamins B1 and B6 and pantothenic acid. 2-Oxo acids were reacted with 1,2-diamino-4,5-methylenebenzene to produce fluorescent derivatives, which were then separated using a TSKgel ODS-80Ts column with 30 mmol/L of KH2PO4 (pH 3.0):acetonitrile (7:3) at a flow rate of 1.0 mL/min. Vitamin B1 deficiency increased urinary levels of all 2-oxo acids, while vitamin B6 deficiency only increased levels of sum of 2-oxaloacetic acid and pyruvic acid, and pantothenic acid deficiency only increased levels of 2-oxoisovaleric acid. Profiles of 2-oxo acids in urine samples might be a non-invasive way of clarifying the functional biomarker of B-group vitamins.
Group and sparse group partial least square approaches applied in genomics context
Authors: Liquet Benoît , de Micheaux Pierre Lafaye , Hejblum Boris P. , Thiébaut Rodolphe
Published: September 2015

Motivation: The association between two blocks of ‘omics’ data brings challenging issues in computational biology due to their size and complexity. Here, we focus on a class of multivariate statistical methods called partial least square (PLS). Sparse version of PLS (sPLS) operates integration of two datasets while simultaneously selecting the contributing variables. However, these methods do not take into account the important structural or group effects due to the relationship between markers among biological pathways. Hence, considering the predefined groups of markers (e.g. genesets), this could improve the relevance and the efficacy of the PLS approach.

Results: We propose two PLS extensions called group PLS (gPLS) and sparse gPLS (sgPLS). Our algorithm enables to study the relationship between two different types of omics data (e.g. SNP and gene expression) or between an omics dataset and multivariate phenotypes (e.g. cytokine secretion). We demonstrate the good performance of gPLS and sgPLS compared with the sPLS in the context of grouped data. Then, these methods are compared through an HIV therapeutic vaccine trial. Our approaches provide parsimonious models to reveal the relationship between gene abundance and the immunological response to the vaccine.

Availability and implementation: The approach is implemented in a comprehensive R package called sgPLS available on the CRAN.

Contact:  b.liquet@uq.edu.au

Supplementary information:  Supplementary data are available at Bioinformatics online.
Natural vs. fishing disturbance: drivers of community composition on traditional king scallop,
Pecten maximus,
fishing grounds
Authors: Szostek Claire L. , Murray Lee G. , Bell Ewen , Rayner Gemma , Kaiser Michel J.
Published: September 2015

Scallop dredging is considered to be one of the most damaging forms of fishing to benthic habitats, although these effects vary among different habitats. The present study characterizes the biological communities that occur within the spatial limits of the English Channel king scallop dredge fishery in relation to key environmental drivers [mean seabed temperature; seabed temperature range; interannual temperature variation; bed shear stress (BSS); substrate characteristics; and depth] and across a gradient of scallop dredging intensity derived from vessel monitoring system data. Dredge fishing intensity was not correlated with species richness, species diversity, or species composition. However, increasing tidal BSS had a significant negative correlation with species richness and diversity. This outcome indicates that it is not possible to demonstrate that there is an effect of scallop fishing within the current spatial limits of the king scallop dredge fishery. This may be because historical dredge fishing could have already altered the benthic communities within the area of the scallop fishery to those that are resilient to scallop dredging, or that fishing disturbance has no impact over and above natural physical disturbance within the fishery. An analysis of biological and life history traits revealed that there was no relationship between recent fishing intensity, or BSS, and the functional composition of the communities present. However, even the lowest BSS values in the present study could be considered relatively high compared with areas outside the spatial boundaries of the fishery. Two distinct habitat groups were identified, based on the environmental drivers. These two groups were largely characterized by depth: deep (western) and shallow (eastern) sites. Species with traits that increase resilience to physical disturbance were abundant across all sample sites. Management concerning the environmental impacts of the fishery is discussed in terms of the spatial footprint of the fishery and predicted recovery time-scales for the associated benthic communities.
Materialisms
Authors: Wingrove Elizabeth
Published: September 2015

This chapter explores the diverse, sometimes discordant ways in which commitments to materialism have shaped feminist theoretical inquiry. Focusing on two alternative interpretive frameworks—historical materialist feminisms (HMF) and feminist new materialisms (FNM)—the chapter considers how distinct understandings of “materiality” sustain alternative accounts of agency, power, and difference. The chapter aims to highlight how these appeals to markedly different notions of a material “real” lead to markedly different interpretive grammars: one (HMF) emphasizing systematicity and the durability of structured relations, the other (FNM) emphasizing indeterminacy, flux, and the “messiness” of the world. Among the stakes identified in these interpretive differences are how physical bodies, processes of embodiment, and nature figure in feminist analyses; how the relationship between matter and representational systems is conceptualized; and whether oppression should serve as a central or secondary locus of analytic concern.
Causation in Science
Authors: Woodward James
Published: September 2015

This article discusses some philosophical theories of causation and their application to several areas of science. Topics addressed include regularity, counterfactual, and causal process theories of causation; the causal interpretation of structural equation models and directed graphs; independence assumptions in causal reasoning; and the role of causal concepts in physics. In connection with this last topic, this article focuses on the relationship between causal asymmetries, the time-reversal invariance of most fundamental physical laws, and the significance of differences among varieties of differential equations (e.g., hyperbolic versus nonhyperbolic) in causal interpretation. It concludes with some remarks about “grounding” special science causal generalizations in physics.
Growth and Maturation of Children and Adolescents
Authors: Rogol Alan D.
Published: September 2015

Normal growth of a child or adolescent likely indicates his or her good general health and well-being. However, there is great variability in the heights and weights that are within the range of normal. Abnormally slow growth may indicate a pathological process or disruption of the environment. Height is a genetically determined parameter, but, at least in the human, it is affected by the interactions of hundreds of genes. In otherwise well children, perhaps 80% of the variance is inherited. Pubertal maturation follows a “fixed” sequence in boys and girls, but its timing and tempo are both determined by the interactions of multiple genes. Environmental effects may play a role in the early initiation of puberty in the obese and the delayed initiation in those with caloric deprivation. Subjects with pathologic growth trajectories deserve medical evaluation because those processes may be abrogated with proper treatment.
The Chronology of Colonization in Remote Oceania
Authors: Rieth Timothy , Cochrane Ethan E.
Published: September 2015

Colonization of Remote Oceania resulted in the discovery of thousands of islands spread across an enormous area of the Pacific Ocean. Beginning as early as approximately 3500 cal. B.P. in Western Micronesia, populations began an expansion westward eventually settling East Polynesia over two millennia later. Although this general pattern is well-established, the reliability of colonization chronologies for particular islands and island groups varies significantly. This chapter synthesizes and critiques current interpretations of radiocarbon and other dating estimates for colonization of the major islands across the region and provides recommendations for future research and chronology building, highlighting the potential for Bayesian analyses. Estimates for the colonization of Hawai'i are presented as a case study.
Victimization Surveys
Authors: Bradford Ben , MacQueen Sarah
Published: September 2015

This chapter considers the history, development, and uses of crime victimization surveys. Offering a wide view of the topic at hand, discussion ranges from the historical development and political economy of crime surveys to consideration of the many methodological challenges they face. A key thread running through the chapter, however, is that although they face many intractable problems, crime surveys are indispensible in terms of generating insight into temporal change in levels of crime and investigating the distribution of various forms of victimization across the population. Despite growing budgetary constraints, victimization surveys look set to continue as part of academic and policy attempts to “know” crime.
Japanese Phenomenology
Authors: Tani Tōru
Published: September 2015

This chapter is an introduction to Japanese phenomenology, which was brought to Japan in the early twentieth century by Nishida Kitarō and others, soon after Husserl launched the movement in Germany. Beginning with a brief historical and cultural overview, the chapter focuses on four major phenomenologists: Sakabe Megumi, Nitta Yoshihiro, Noé Keiichi, and Washida Kiyokazu. Each of the four, each in a different way, articulates a fundamental aspect of Japanese phenomenology: the criticism of subject-object dualism and the attending idea of an autonomous being-in-itself. All attempt to inquire more deeply into the nondual dimensions underlying that dualism: Sakabe through an inquiry into betweenness (aida or awai), encounter, and reflection (utsushi); Nitta by probing the depths of “verticality” and “mediality”; Noé by investigating the relationship between narrative and experience; and Washida by transgressing the borders of philosophy and pursuing more “reversibility” in human relationships.