bluuebunny/crossref_metadata_2025 huggingface dataset:
The South China Sea: Paleoceanography and Sedimentology
Authors: Ding Zhongli
Published: March 2010

The South China Sea is the largest low‐latitude marginal sea on the globe. For a long time, researchers from various fields have been curious about the sea. For instance, geologists pay particular attention to the spreading history of the sea basin; they believe that the spreading of the sea more than 30 million years ago was probably caused by southward extrusion of the Indo‐China Peninsula Block due to uplift of the Tibetan Plateau following the collision between the Indian and Eurasian plates. Furthermore, the South China Sea now provides almost half of the water vapor for the East Asian monsoon. The formation and evolution of the monsoon relate closely to the uplift history of the Tibetan Plateau. Consequently, climatologists want to understand the commencement of the monsoon circulation over East Asia and its relationship with the evolution of the South China Sea. In addition, the sea is characterized by a broad shelf and a broad slope, now under very thick sediments. Over the years, scientists in industry and academia have carried out many studies on the voluminous petroleum and gas hydrate resources stored in the deposits. The enhanced surface weathering processes after plateau uplift may have also exerted a strong influence on global carbon cycling, and this process should have been recorded in the sea sediments. In short, scientists consider the South China Sea a valuable site for studying the interactions between different spheres of the Earth system.
Biological Extreme Events: A Research Framework
Authors: Gutschick Vincent P. , BassiriRad Hormoz
Published: March 2010

Efforts designed to understand and predict adaptation responses of organisms and populations to global climate change must make a clear distinction between responses to changes in average conditions (e.g., doubling of atmospheric carbon dioxide concentration accompanied by an average increase of 1°–3°C in global air temperature by the end of this century) and responses resulting from increased incidence of extreme events [Loehle and LeBlanc, 1996; Easterling et al., 2000; Garrett et al., 2006]. Such distinction is critical because, unlike changes in average conditions, extremes (e.g., megadroughts, fire, flooding, hurricanes, heat waves, and pest outbreaks) are typically short in duration but challenge organisms and populations considerably further beyond their ability to acclimate than those expected from average trends in climate changes.
Blood–Brain Barrier Permeability for Ammonia in Patients with Different Grades of Liver Fibrosis is Not Different from Healthy Controls
Authors: Goldbecker Annemarie , Buchert Ralph , Berding Georg , Bokemeyer Martin , Lichtinghagen Ralf , Wilke Florian , Ahl Björn , Weissenborn Karin
Published: March 2010

Increased blood-brain barrier (BBB) permeability for ammonia is considered to be an integral part of the pathophysiology of hepatic encephalopathy (HE) in patients with liver cirrhosis. Increased glutamate-/glutamine-signal intensity in magnetic resonance spectroscopic studies of the brain in cirrhotic patients was explained as a consequence of increased cerebral ammonia uptake. As similar spectroscopic alterations are present in patients with liver fibrosis, we hypothesized that BBB permeability for ammonia is already increased in liver fibrosis, and thereby contributing to the development of HE. To test this hypothesis, cerebral perfusion and ammonia metabolism were examined through positron emission tomography with 15O-water, respectively, 13N-ammonia in patients with Ishak grades 2 and 4 fibrosis, cirrhosis, and healthy controls. There were neither global nor regional differences of cerebral blood flow, the rate constant of unidirectional transport of ammonia from blood into brain tissue, the permeability surface area product of the BBB for ammonia, the net metabolic clearance rate constant of ammonia from blood into glutamine in brain, or the metabolic rate of ammonia. The hypothesis that increased permeability of the BBB for ammonia in patients with liver fibrosis contributes to the later development of HE could not be supported by this study.
Acid-Sensing Ion Channels in Acidosis-Induced Injury of Human Brain Neurons
Authors: Li Minghua , Inoue Koichi , Branigan Deborah , Kratzer Eric , Hansen Jillian C , Chen Jeff W , Simon Roger P , Xiong Zhi-Gang
Published: March 2010

Acidosis is a common feature of the human brain during ischemic stroke and is known to cause neuronal injury. However, the mechanism underlying acidosis-mediated injury of the human brain remains elusive. We show that a decrease in the extracellular pH evoked inward currents characteristic of acid-sensing ion channels (ASICs) and increased intracellular Ca2+ in cultured human cortical neurons. Acid-sensing ion channels in human cortical neurons show electrophysiological and pharmacological properties distinct from those in neurons of the rodent brain. Reverse transcriptase-PCR and western blot detected a high level of the ASIC1a subunit with little or no expression of other ASIC subunits. Treatment of human cortical neurons with acidic solution induced substantial cell injury, which was attenuated by the ASIC1a blockade. Thus, functional homomeric ASIC1a channels are predominantly expressed in neurons from the human brain. Activation of these channels has an important role in acidosis-mediated injury of human brain neurons.
Circadian Preference and Sexual Selection: A Novel Evolutionary Approach
Authors: Piffer Davide
Published: March 2010

Human sleep patterns differ across age groups and between males and females, and their association with age and gender suggest that they might have been the target of sexual selection during human evolutionary history. In this study, I will test the hypothesis that a phase-delayed circadian phase is a sexually selected trait in humans. A short version of the Horne and Ostberg questionnaire and a questionnaire on sexual behaviour were administered to 134 males and 140 females. A significant negative relationship was found between the MEQ score and the number of sexual partners among males, with evening types reporting more sexual partners than morning types. No significant relationship between females MEQ and number of sexual partners was found. Findings support the hypothesis that evening preference in males is a sexually selected trait.
Working With English Language Learners in Preschool Settings
Authors: Moxley Andrea “Deedee”
Published: March 2010

Nearly one out of every five children speaks a language other than English in the home. It is difficult to determine language difference versus disorder. Speech-language pathologists who serve preschool-aged children are being asked to serve typically developing second language learners and work without the assistance of an interpreter/translator. It is important to be familiar with legislation, ASHA policy, and research to provide culturally and linguistically appropriate services.
Outcomes in Mild to Moderately-Severe Hearing Impairment in Children: Recent Research Findings and Clinical Applications
Authors: Hoover Brenda M.
Published: March 2010

Work at Boys Town National Research Hospital, in both the Hearing and Amplification Research Laboratory and the Infant Development Laboratory, has focused on the optimization of amplification for infants and young children for many years. In this paper we review recent work, including outcomes in a five-year longitudinal study of children with early-identified hearing loss compared to normal-hearing peers. Findings in studies of hearing-aid bandwidth and noise-reduction strategies also are reviewed, and clinical implications are discussed.
Music Perception in Children With Cochlear Implants
Authors: Scattergood Lindsay , Limb Charles J.
Published: March 2010

As a result of the widespread use of cochlear implants, individuals with profound hearing loss now are able to hear sounds ranging from a syllable to a symphony. This form of “electric hearing” has been remarkably successful in providing sound to the deaf population and at least 100,000 implantation procedures have been performed worldwide in more than 80 countries (Clark, 2008). Today, it is routine for post-lingual deafened individuals (one who lost their hearing after normal childhood language acquisition) to achieve high performance on language tests following implantation (Lalwani, Larky, Wareing, Kwast, & Schindler, 1998). Deaf children implanted at an early age with a CI usually develop excellent spoken language skills, with placement into mainstream educational schooling (Francis, Koch, Wyatt, & Niparko, 1999). The overwhelming emphasis on language perception in CI users has led to relative neglect of non-linguistic sound perception. Yet, the auditory world consists of many other sounds besides those of spoken language. Of all non-linguistic sounds, perception of music—particularly pitch and timbre—represents the greatest challenge for implant-mediated listening (Limb, 2006). High-level perception of music rarely is attained through conventional speech processing technology in adults or children. Recent technological advances, however, have increased the processing capabilities of modern CIs and hold great promise for music perception and quality of life for children with cochlear implants (Lassaletta et al., 2007).
Making the Move to Private Practice: Using Your Sense To Make Cents
Authors: Nikjeh Dee Adams , Carroll Linda M.
Published: March 2010

Making the move to private practice can be an exciting and challenging proposition. There are many practical, professional, and personnel issues to consider. This tutorial provides practical suggestions for transitioning into a private practice including considerations for referral base, office space, personnel, and practice management. In addition, two major health-care coding systems are described, and the relationship of these systems to clinical documentation (Medicare Physician Fee Schedule and equitable reimbursement) is explained. Information about the use of coding edits and coding modifiers is provided. Also included in this tutorial is a brief discussion of the impact that Public Law 110-275: Medicare Improvements for Patients and Providers Act of 2008 has had on the valuation of speech-language pathology procedure codes, particularly for assessment and treatment of individuals with voice disorders.
Experimental demonstration of the negative refraction of a transverse elastic wave in a two-dimensional solid phononic crystal
Authors: Morvan Bruno , Tinel Alain , Hladky-Hennion Anne-Christine , Vasseur Jérôme , Dubus Bertrand
Published: March 2010

The negative refraction of transverse elastic waves is demonstrated experimentally in a two-dimensional phononic crystal (PC) made of a square lattice of cylindrical air cavities in an aluminum matrix. Dispersion curves of elastic waves in this PC exhibit a unique branch with phase and group velocities of opposite signs in a broad frequency range. Measurement of refraction angles through prismatic PC included in an aluminum block demonstrates negative refraction of elastic transverse wave.
Structural, electrical, and magnetic properties of Mn2.52−xCoxNi0.48O4 films
Authors: Wu Jing , Huang Zhiming , Hou Yun , Gao Yanqing , Chu Junhao
Published: March 2010

The serial films of Mn2.52−xCoxNi0.48O4 (x=0, 0.32, 0.64, and 0.96) with fixed Ni content of 0.48 are prepared on amorphous Al2O3 substrate by chemical solution deposition method. The x-ray diffraction and microstructure analyses indicate that Co/Mn content ratio can modify the preferred crystalline growth direction and the microstructure morphology of different composition is different under the same growth condition. The distribution of the cations for the four compositions is estimated based on the lattice constant and cation radii. The dc resistivity measurements demonstrate our speculation of the cation distributions. The electrical and magnetic measurements show that the thermal activation energy decreases but the ferrimagnetic transition temperature increases with the increase in Co content. The magnetization loop tests indicate that Mn2.52−xCoxNi0.48O4 serial films probably possess magnetic anisotropy with ⟨111⟩ magnetically easy axis.
Europium luminescence enhancement induced by a resonant mode in a waveguide of planar metallic walls
Authors: Ramírez-Duverger Aldo S. , Aceves R. , García-Llamas Raúl , Gaspar-Armenta Jorge A.
Published: March 2010

We report the experimental results of emission from europium ions inside a planar waveguide. The waveguide is constituted by a MgF2:Eu2+ film between Al metallic walls, with a film thickness appropriate to support a guided mode with wavelength inside of the excitation spectrum of the Eu ions. A guided mode is produced by incident light through a thin metallic film at an angle of incidence such that its wave vector component parallel to the waveguide couples resonantly to the mode. The luminescence of Eu2+ in the waveguide of polycrystalline MgF2 was found to have a maximum at 440 nm. This emission was ascribed to electronic transitions of Eu2+ ions dipoles on a lattice of MgF2. For an excitation light of 360 nm, the integrated emission versus angle of incidence showed a maximum for an incident light angle of 20°. This behavior is explained because of the excitation light, for those wavelength and angle of incidence, couple to a mode along the waveguide and more emitters are excited in the optical path of the guided light.
A complete accounting of the monoenergetic electron parameters in an ellipsoidal bubble model
Authors: Sadighi-Bonabi R. , Rahmatollahpur SH.
Published: March 2010

A reliable analytical expression for the potential of plasma waves with phase velocities near the speed of light is derived. The presented ellipsoid cavity model is more consistent than the previous spherical model and it explains the monoenergetic electron trajectory more accurately especially in the relativistic regime. The electron energy spectrum is also calculated and it is found that the energy distribution ratio of electrons ΔE/E for the ellipsoid model in the here reported condition is about 10%, which is less than half that of the spherical model (25%) and it is in good agreement with the experimentally measured value of 12% under the same condition. The experimental measurements reported here are based on focusing of 500 mJ and 30 fs laser pulse in the best matched point above the pulsed He gas nozzle, which produces a stable ellipsoidal bubble where the obtained electron parameters are much closer to the parameters calculated by the ellipsoidal model. It is found that the quasimonoenergetic electron beam interacting with the laser plasma is more appropriately described with this model.
Structural, optical, and ferromagnetic properties of Co-doped TiO2 films annealed in vacuum
Authors: Xu Jianping , Shi Shaobo , Li Lan , Zhang Xiaosong , Wang Yaxin , Chen Ximing , Wang Jianfeng , Lv Liya , Zhang Fengming , Zhong Wei
Published: March 2010

Polycrystalline anatase Ti1−xCoxO2 (x=0–0.06) films have been fabricated by sol-gel spin coating. The effects of Co doping on the structural, optical, and magnetic properties are investigated. It is shown that oxygen vacancies and/or defects in the films are generated during thermal treatment in vacuum. Co doping reduces crystal quality and inhibits crystalline grain growth. Due to the introduction of Co, photoluminescence (PL) spectra become weak and the band gap emission has a blueshift. PL spectra reveal that the solubility of Co is lower than 0.02. At 300 K, the saturated magnetization is around 1.8 μB/Co, which is independent of the concentration of Co. This value is approximately equivalent to the average magnetic moment of bulk metallic cobalt (1.75 μB/Co). Zero-field-cooling/field-cooling measurements indicate that room temperature ferromagnetism in Co-doped TiO2 films is not an intrinsic property of the material. The presence of Co metal is identified by x-ray photoelectron spectroscopy and scanning electron microscopy.
Note: Simultaneous measurement of surface plasmon resonance and surface-enhanced Raman scattering
Authors: Liu Yu , Xu Shuping , Tang Bin , Wang Ye , Zhou Ji , Zheng Xianliang , Zhao Bing , Xu Weiqing
Published: March 2010

A surface plasmon resonance (SPR)-surface enhanced Raman scattering (SERS) microspectrometer was designed to obtain the incident angle dependence of SERS signals excited by the evanescent field. By simultaneous measurement of the SERS and SPR spectra of analytes, the highest SERS signal intensities were found to appear at the vicinity of the resonance angle. The enhancement factor was about 2.0×106. The simulated angle of the maximal SERS intensity based on Fresnel equation was found to be in good agreement with the experimental results. The SERS and SPR spectra captured simultaneously not only directly confirm the correlation between the SERS and SPR but also present a potential technique for obtaining the structure information about the analytes in molecule level with recording their SPR curves.
Analysis of heterostructures for electroluminescent refrigeration and light emitting without heat generation
Authors: Yen Shun-Tung , Lee Kuan-Chen
Published: March 2010

We perform a self-consistent calculation to investigate the feasibility of electroluminescent refrigeration and light emitting without heat generation in AlGaAs/GaAs heterostructures, taking into account the effects of various recombination processes. The effect of radiation extraction on the cooling capacity and efficiency is also considered. Carrier blocking layers are used to almost eliminate current leakage and improve the injection efficiency to nearly 100%. An analysis is presented of the cooling power density, the cooling efficiency, and the radiative power density as functions of the applied voltage. We also explore the dependences of the cooling related quantities on the thickness and the doping of the active region. A GaAs active layer of thickness 5 μm at 300 K can give a limiting cooling power density of 97 W/cm2. We show that a net cooling power (>several W/cm2) and a high-power light emitting (>100 W/cm2) without heating are feasible. They require an overall efficiency of more than 90%, which is easily achieved if the photon recycling efficiency is high.
The leading-edge vortex and quasisteady vortex shedding on an accelerating plate
Authors: Chen Kevin K. , Colonius Tim , Taira Kunihiko
Published: March 2010

A computational inquiry focuses on leading-edge vortex (LEV) growth and shedding during acceleration of a two-dimensional flat plate at a fixed 10°–60° angle of attack and low Reynolds number. The plate accelerates from rest with a velocity given by a power of time ranging from 0 to 5. During the initial LEV growth, subtraction of the added mass lift from the computed lift reveals an LEV-induced lift augmentation evident across all powers and angles of attack. For the range of Reynolds numbers considered, a universal time scale exists for the peak when α≥30°, with augmentation lasting about four to five chord lengths of translation. This time scale matches well with the half-stroke of a flying insect. An oscillating pattern of leading- and trailing-edge vortex shedding follows the shedding of the initial LEV. The nondimensional frequency of shedding and lift coefficient minima and maxima closely match their values in the absence of acceleration. These observations support a quasisteady theory of vortex shedding, where dynamics are determined primarily by velocity and not acceleration. Finally, the nondimensional vortex formation time is found to be a function of the Reynolds number, but only weakly when the Reynolds number is high.
Detailed studies on energy loss mechanism in phosphor-sensitized fluorescent polymer light-emitting devices
Authors: Ye Tengling , Shao Shiyang , Chen Jiangshan , Chen Zhenyu , Wang Lixiang , Ma Dongge
Published: March 2010

We studied the main energy loss mechanism in electroluminescent (EL) processes in phosphor-sensitized fluorescent polymer light-emitting devices. The used organometallic phosphor is fac-tris(2-phenyl-pridine) iridium [Ir(ppy)3] and the used red fluorescent dye is 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetrame-thyljulolidyl-9-enyl)-4H-pyran (DCJTB). The investigation found that due to the stronger electron trapping ability of DCJTB than that of Ir(ppy)3, the excitons prefer to form on DCJTB molecules. The charge trapping on the DCJTB molecules obviously restrain the function of the phosphor-sensitizer Ir(ppy)3. Moreover, the energy transfer from phosphorescent triplet state (Tp) to the fluorescent triplet state (Tf) also has great negative impact on the phosphor-sensitized fluorescent process. We clearly demonstrated these energy loss processes by steady-state and transient photoluminescence and comparison of device efficiency.
Thermal equilibrium noise with 1/f spectrum from frequency independent dielectric losses in barium strontium titanate
Authors: Vandamme L. K. J. , Khalfallaoui A. , Leroy G. , Vélu G.
Published: March 2010

We investigated the dielectric losses of doped and undoped BaSrTiO3 (BST) from thermal noise measurements. The results are compared to impedance measurements. The value for the frequency independent loss angle is about tg δ=2×10−2 in the range 100<f(Hz)<105. The thermal voltage noise of the BST capacitor with losses has a 1/f spectrum in agreement with 4kT R(Z) and a frequency independent tg δ. The detection limits due to the low noise voltage amplifier are investigated and experimentally verified. The frequency range fhigh, flow, where the “1/f thermal noise” is above the background noise is characterized by the ratio fhigh/flow=tg2δ(Rin/Reqw), with Rin the input resistance of the low noise voltage amplifier and Reqw the frequency independent part of its equivalent noise resistance at high frequencies.
Nanospheres generate out-of-plane magnetization
Authors: Amaladass E. , Ludescher B. , Schütz G. , Tyliszczak T. , Lee M.-S. , Eimüller T.
Published: March 2010

Large arrays of ordered magnetic nanostructures have been fabricated by sputter depositing Fe/Gd multilayers on an array of self-assembled nanospheres. On a planar substrate the system shows an in-plane magnetization whereas a spin reorientation transition (SRT) to out-of-plane orientation occurs on the spherules. This SRT cannot only be explained by the reduction in the shape anisotropy due to patterning of the extended film into nanometer sized islands. In fact, more important is the curved surface of the film on the nanocaps. Micromagnetic simulations of various geometries reveal that the crescent shape of the magnetic film on the spheres is ideal to get small values of the shape anisotropy for all diameters of the spheres, ranging from 1 μm down to 20 nm. The observed SRT enables a simple and cost effective bottom-up approach to produce patterned perpendicular magnetic nanostructures, having a high potential for magnetic data storage and spintronic applications.
Nonmagnetic Fe-site doping of BiFeO3 multiferroic ceramics
Authors: Wei Jie , Haumont Raphael , Jarrier Romain , Berhtet Patrik , Dkhil Brahim
Published: March 2010

In this paper, we show that a pure single phase by doping Fe-site of BiFeO3 (BFO) using tetravalent Zr4+ ions can be achieved by introducing cation (Bi3+) vacancies. The structural analysis reveals that the ferroelectric nature of BFO should be weakly affected by 10% of Zr4+ doping as the c/a ratio and the Curie temperature TC remain roughly unchanged compared to that of pure BFO. In contrast, the magnetic properties are affected as a weak ferromagnetism and a change of Néel temperature TN are observed. Beyond the double-exchange interactions arising from the creation of Fe2+, we propose another simple model inducing a local ferromagnetic coupling rather than an antiferromagnetic which considers the replacement of the magnetically active Fe3+, time to time, by a nonactive Zr4+.
N
-fold supersymmetry and quasi-solvability associated with X2-Laguerre polynomials
Authors: Tanaka Toshiaki
Published: March 2010

We construct a new family of quasi-solvable and N-fold supersymmetric quantum systems where each Hamiltonian preserves an exceptional polynomial subspace of codimension 2. We show that the family includes as a particular case the recently reported rational radial oscillator potential whose eigenfunctions are expressed in terms of the X2-Laguerre polynomials of the second kind. In addition, we find that the two kinds of the X2-Laguerre polynomials are ingeniously connected with each other by the N-fold supercharge.
Modification of magnetic properties through the control of growth orientation and epitaxial strain in SrRuO3 thin films
Authors: Lee B. W. , Jung C. U.
Published: March 2010

We studied the correlation between the magnetic properties and the structural modifications in SrRuO3 thin films. Previous results on the control of growth orientation in SrRuO3 thin film have been rather limited. For example, only orthorhombic a-axis growth could be obtained for SrRuO3 film on SrTiO3 (110) substrates. Here we were able to obtain various SrRuO3 films with (100)o, (010)o, and (111)o growth orientations, as well as with different amount of strain on SrTiO3 (110) substrates by using (Ca,Sr)SnO3 and CaHfO3 buffer layers. The magnetic properties were found to change systematically with the structural distortion of the SrRuO3 thin films.
Microwave switching of graphene field effect transistor at and far from the Dirac point
Authors: Deligeorgis G. , Dragoman M. , Neculoiu D. , Dragoman D. , Konstantinidis G. , Cismaru A. , Plana R.
Published: March 2010

The dc and microwave experiments on a top-gate field effect transistor based on graphene, at and far from the Dirac point, are reported. Far from the Dirac point the transistor behaves as an active device, while at the Dirac point the transistor becomes a passive device, its amplification being suppressed due to a reduction in the carrier density. Microwave switches can be implemented using this property. The maximum stable gain of the transistor is preserved up to 5 GHz.
Low subthreshold slope in junctionless multigate transistors
Authors: Lee Chi-Woo , Nazarov Alexei N. , Ferain Isabelle , Akhavan Nima Dehdashti , Yan Ran , Razavi Pedram , Yu Ran , Doria Rodrigo T. , Colinge Jean-Pierre
Published: March 2010

The improvement of subthreshold slope due to impact ionization is compared between “standard” inversion-mode multigate silicon nanowire transistors and junctionless transistors. The length of the region over which impact ionization takes place, as well as the amplitude of the impact ionization rate are found to be larger in the junctionless devices, which reduces the drain voltage necessary to obtain a sharp subthreshold slope.
Surface-enhanced fluorescence of praseodymium ions (Pr3+) on silver/silicon nanostructure
Authors: Zhuo Shujuan , Shao Mingwang , Cheng Liang , Que Ronghui , Zhuo Shujuan , Duo Ma Dorthy Duo , Lee Shuit-Tong
Published: March 2010

The enhanced fluorescence of praseodymium ions (Pr3+) owing to resonant plasma oscillation on the surface of Ag/Si nanostructure was investigated. When Ag/Si nanomaterials were added, the fluorescence peaks were markedly enhanced. A typical 12- to 40-fold enhancement at 604 nm and 18- to 193-fold enhancement at 640 nm could be achieved over a range of concentration from 0.01 to 0.05 M praseodymium ions, which had larger enhancement factor than that caused by unsupported silver nanoparticles. These results might be explained by the local field overlap originated from the closed and fixed silver nanoparticles on silicon nanowires.
Higher order conformation of poly(3-hydroxyalkanoates) studied by terahertz time-domain spectroscopy
Authors: Hoshina Hiromichi , Morisawa Yusuke , Sato Harumi , Kamiya Akitsugu , Noda Isao , Ozaki Yukihiro , Otani Chiko
Published: March 2010

Terahertz absorption spectra of poly(3-hydroxyalkanoates) with different conformations were measured by using a terahertz time domain spectrometer. Sharp absorption peaks were observed in the spectrum of crystalline samples. The orientation direction of the transition dipole moment was investigated by the polarization spectra. The peak at 2.92 THz was assigned to a vibration of helical structure along the fiber axis, and the peak at 2.49 THz was attributed to a vibration due to the hydrogen bonding between helix structures. The temperature dependence of the spectra reflects the change in the hydrogen bonding distance and melting process of the crystalline structure.
Dielectrophoretically tuneable optical waveguides using nanoparticles in microfluidics
Authors: Kalantar-zadeh K. , Khoshmanesh K. , Kayani A. A. , Nahavandi S. , Mitchell A.
Published: March 2010

We present a tuneable optical waveguide using dielectrophoretically controlled nanoparticles in microfluidics. Silicon dioxide nanoparticles of different sizes in de-ionized water are channelled through a microfluidic system. An array of microelectrodes generates the dielectrophoretic force to funnel nanoparticles, forming narrowbands at the center of the microfluidics at different applied voltages and frequencies. It is observed that these narrowbands either scatter or guide the coupled light under selected conditions. The realization of such a system offers exciting possibilities for the development of a new class of optofluidics, which are tuned by the positioning of nanoparticles on demand.
Spin-torque driven magnetic vortex self-oscillations in perpendicular magnetic fields
Authors: Finocchio G. , Pribiag V. S. , Torres L. , Buhrman R. A. , Azzerboni B.
Published: March 2010

We have employed complete micromagnetic simulations to analyze dc current driven self-oscillations of a vortex core in a spin-valve nanopillar in a perpendicular field by including the coupled effect of the spin-torque and the magnetostatic field computed self-consistently for the entire spin-valve. The vortex in the thicker nanomagnet moves along a quasielliptical trajectory that expands with applied current, resulting in “blueshifting” of the frequency, while the magnetization of the thinner nanomagnet is nonuniform due to the bias current. The simulations explain the experimental magnetoresistance-field hysteresis loop and yield good agreement with the measured frequency versus current behavior of this spin-torque vortex oscillator.
Experimental evidence of enhanced electro-optic control on a lithium niobate photonic crystal superprism
Authors: Amet J. , Ulliac G. , Baida F. I. , Bernal M.-P.
Published: March 2010

We present experimental evidence of an electro-optic superprism photonic crystal fabricated on a lithium niobate substrate, in agreement with simulation results. In this work, rather than changing the incident wavelength or angle to achieve large light deflections, a direct modification of the band structure by the electro-optic effect causes changes in the propagation direction of the incident beam. Additionally, the chosen geometry allows significant ultrarefraction as the incident wavelength is varied giving rise to a double purpose active-passive photonic crystal light deflector that could present potential interest for optical communications.
Super-reflection and cloaking based on zero index metamaterial
Authors: Hao Jiaming , Yan Wei , Qiu Min
Published: March 2010

A zero index metamaterial (ZIM) can be utilized to block wave (super-reflection) or conceal objects completely (cloaking). The “super-reflection” device can be realized by a Mu zero (Epsilon zero) metamaterial with a perfect electric (magnetic) conductor inclusion of arbitrary shape and size for a transverse electric (magnetic) incident wave. In contrast, a Mu zero (Epsilon zero) metamaterial with a perfect magnetic (electric) conductor inclusion for a transverse electric (magnetic) incident wave can be used to conceal objects of arbitrary shape. The underlying physics here is determined by the intrinsic properties of the ZIM.
Pulsar Timing with the Parkes Radio Telescope for the Fermi Mission
Authors: Weltevrede P. , Johnston S. , Manchester R. N. , Bhat R. , Burgay M. , Champion D. , Hobbs G. B. , Kızıltan B. , Keith M. , Possenti A. , Reynolds J. E. , Watters K.
Published: March 2010

We report here on two years of timing of 168 pulsars using the Parkes radio telescope. The vast majority of these pulsars have spin-down luminosities in excess of 1034 erg s−1 and are prime target candidates to be detected in gamma-rays by the Fermi Gamma-Ray Space Telescope. We provide the ephemerides for the ten pulsars being timed at Parkes which have been detected by Fermi in its first year of operation. These ephemerides, in conjunction with the publicly available photonlist, can be used to generate gamma-ray profiles from the Fermi archive. We will make the ephemerides of any pulsars of interest available to the community upon request. In addition to the timing ephemerides, we present the parameters for 14 glitches which have occurred in 13 pulsars, seven of which have no previously known glitch history.The Parkes timing programme, in conjunction with Fermi observations, is expected to continue for at least the next four years.
Floral ontogeny of Brunonia australis (Goodeniaceae) and Calandrinia sp. (Portulacaceae)
Authors: Cave Robyn L. , Birch Colin J. , Hammer Graeme L. , Erwin John E. , Johnston Margaret E.
Published: March 2010

Floral ontogeny of Brunonia australis Sm. ex R.Br. (blue pincushion) and Calandrinia sp. (not yet fully classified) was investigated by scanning electron microscopy to assist further efforts for manipulating flowering of these potential floriculture crops. This is the first work to study floral initiation and the stages of flower development for these species. Floral initiation of B. australis commenced 28 days after seed germination when grown at 25/10 or 35/20°C (day/night) under long days (11 h of ambient light at 553 ± 45 µmol m–2 s–1, plus a 5-h night break at <4.5 µmol m–2 s–1). Leaf number at floral initiation reflected differences in the accumulated thermal time between treatments so that about double the number of leaves formed at 35/20°C. This suggested differing temperature responses for leaf and phenological development, and that leaf number was not a good indicator of floral initiation. For Calandrinia sp., floral initiation commenced 47 days after seed germination when grown at 25/10°C. Hot temperatures (35/20°C) inhibited flowering; indicating a vernalisation requirement. For B. australis, the pattern of floret development was centripetal, with flowers organised into five whorls. Four bracts surrounded each flower, whereas the sepals, petals and stamens showed a pentamerous arrangement. A central style was terminated by an indusial stigmatic presenter. Flowers of Calandrinia sp. consisted of four whorls, namely two sepals, 8–10 petals, numerous stamens produced centrifugally and a central syncarpous gynoecium with four stigmatic branches.
Superheating of ice crystals in antifreeze protein solutions
Authors: Celik Yeliz , Graham Laurie A. , Mok Yee-Foong , Bar Maya , Davies Peter L. , Braslavsky Ido
Published: March 2010

It has been argued that for antifreeze proteins (AFPs) to stop ice crystal growth, they must irreversibly bind to the ice surface. Surface-adsorbed AFPs should also prevent ice from melting, but to date this has been demonstrated only in a qualitative manner. Here we present the first quantitative measurements of superheating of ice in AFP solutions. Superheated ice crystals were stable for hours above their equilibrium melting point, and the maximum superheating obtained was 0.44 °C. When melting commenced in this superheated regime, rapid melting of the crystals from a point on the surface was observed. This increase in melting temperature was more appreciable for hyperactive AFPs compared to the AFPs with moderate antifreeze activity. For each of the AFP solutions that exhibited superheating, the enhancement of the melting temperature was far smaller than the depression of the freezing temperature. The present findings clearly show that AFPs adsorb to ice surfaces as part of their mechanism of action, and this absorption leads to protection of ice against melting as well as freezing.
A Pair of Little Gilded Shoes: Commission, Cost, and Meaning in Renaissance Footwear*
Authors: O'Malley Michelle
Published: March 2010

This article focuses on women's luxury footwear to examine issues of economic, material, and familial life in Renaissance Italy. It uses graphic work by Albrecht Dürer to explore footwear design, and draws from disparate sources to propose a new method for evaluating its cost. The article argues that sumptuous footwear was available for a range of prices that are not reflected in surviving payment records, and that it was largely less expensive than moralists and legislators implied. In conclusion, it employs Minerbetti documentation to consider the role particular shoes may have played in developing personal subjectivity.
United States Farm Commodity Programs and Land Use
Authors: Gardner Bruce , Hardie Ian , Parks Peter J.
Published: March 2010

We estimate the impact of government payments on United States land use, using county‐level data from the National Resources Inventory and the Census of Agriculture in 1987, 1992, and 1997. Although payments were made under decoupled support programs, effects on land use are found to be significant. On average for the years studied, our simulations indicate that United States cropland acreage would have been 89 million acres (22%) less if program payments had been reduced to half their observed level (holding market prices of commodities constant). Percentage reductions are largest in marginal crop producing areas of the nation.
Genome-wide synteny through highly sensitive sequence alignment: Satsuma
Authors: Grabherr Manfred G. , Russell Pamela , Meyer Miriah , Mauceli Evan , Alföldi Jessica , Di Palma Federica , Lindblad-Toh Kerstin
Published: March 2010

Motivation: Comparative genomics heavily relies on alignments of large and often complex DNA sequences. From an engineering perspective, the problem here is to provide maximum sensitivity (to find all there is to find), specificity (to only find real homology) and speed (to accommodate the billions of base pairs of vertebrate genomes).

Results: Satsuma addresses all three issues through novel strategies: (i) cross-correlation, implemented via fast Fourier transform; (ii) a match scoring scheme that eliminates almost all false hits; and (iii) an asynchronous ‘battleship’-like search that allows for aligning two entire fish genomes (470 and 217 Mb) in 120 CPU hours using 15 processors on a single machine.

Availability: Satsuma is part of the Spines software package, implemented in C++ on Linux. The latest version of Spines can be freely downloaded under the LGPL license from http://www.broadinstitute.org/science/programs/genome-biology/spines/

Contact:  grabherr@broadinstitute.org
Monitoring long-term evolutionary changes followingWolbachiaintroduction into a novel host: theWolbachia popcorninfection inDrosophila simulans
Authors: Carrington Lauren B. , Hoffmann Ary A. , Weeks Andrew R.
Published: March 2010

Wolbachiamay act as a biological control agent for pest management; in particular, theWolbachiavariantwMelPop (popcorn) shortens host longevity and may be useful for dengue suppression. However, long-term changes in the host andWolbachiagenomes can alterWolbachiaspread and/or host effects that suppress disease. Here, we investigate the phenotypic effects ofwMelPop in a non-native host,Drosophila simulans, following artificial transinfection approximately 200 generations ago. Long-term rearing and maintenance of the bacteria were at 19°C in the original I-102 genetic background that was transinfected with thepopcornstrain. The bacteria were then introgressed into three massbred backgrounds, and tetracycline was used to create uninfected sublines. The effect ofwMelPop on longevity in this species appears to have changed; longevity was no longer reduced at 25°C in some nuclear backgrounds, reflecting different geographical origin, selection or drift, although the reduction was still evident for flies held at 30°C.Wolbachiainfluenced productivity and viability, and development time in some host backgrounds. These findings suggest that long-term attenuation ofWolbachiaeffects may compromise the effectiveness of this bacterium in pest control. They also emphasize the importance of host nuclear background onWolbachiaphenotypic effects.
TheArabidopsis thaliana Myo-Inositol 1-Phosphate Synthase1 Gene Is Required forMyo-inositol Synthesis and Suppression of Cell Death
Authors: Donahue Janet L. , Alford Shannon R. , Torabinejad Javad , Kerwin Rachel E. , Nourbakhsh Aida , Ray W. Keith , Hernick Marcy , Huang Xinyi , Lyons Blair M. , Hein Pyae P. , Gillaspy Glenda E.
Published: March 2010

l-myo-inositol 1-phosphate synthase (MIPS; EC 5.5.1.4) catalyzes the rate-limiting step in the synthesis of myo-inositol, a critical compound in the cell. Plants contain multiple MIPS genes, which encode highly similar enzymes. We characterized the expression patterns of the three MIPS genes in Arabidopsis thaliana and found that MIPS1 is expressed in most cell types and developmental stages, while MIPS2 and MIPS3 are mainly restricted to vascular or related tissues. MIPS1, but not MIPS2 or MIPS3, is required for seed development, for physiological responses to salt and abscisic acid, and to suppress cell death. Specifically, a loss in MIPS1 resulted in smaller plants with curly leaves and spontaneous production of lesions. The mips1 mutants have lower myo-inositol, ascorbic acid, and phosphatidylinositol levels, while basal levels of inositol (1,4,5)P3 are not altered in mips1 mutants. Furthermore, mips1 mutants exhibited elevated levels of ceramides, sphingolipid precursors associated with cell death, and were complemented by a MIPS1-green fluorescent protein (GFP) fusion construct. MIPS1-, MIPS2-, and MIPS3-GFP each localized to the cytoplasm. Thus, MIPS1 has a significant impact on myo-inositol levels that is critical for maintaining levels of ascorbic acid, phosphatidylinositol, and ceramides that regulate growth, development, and cell death.
Morphological variation of perch Perca fluviatilis in humic lakes: the effect of predator density, competition and prey abundance
Authors: Kekäläinen J. , Kähkönen J. , Kiviniemi V. , Huuskonen H.
Published: March 2010

Between and within‐lake variations in morphology of perch Perca fluviatilis were studied in four humic lakes in eastern Finland. Perca fluviatilis were more streamlined and smaller headed in a lake with the highest abundance of cyprinids, but lowest abundance of predators (Lake Tuopanjärvi), indicating adaptation to planktivorous feeding and low predator density. Highest bodied fish were found from a lake with the lowest cyprinid but highest predator abundance (Lake Koppelojärvi), which conversely indicates adaptation to more effective predator avoidance. Furthermore, the length of the paired fins was longest in Lake Kinnasjärvi and Lake Tuopanjärvi, where the abundance of benthic macroinvertebrates was lowest, suggesting selection for more effective benthivory. Clear morphological differences of P. fluviatilis between habitats were found only in Lake Kinnasjärvi, whereas in Lake Koppelojärvi and Lake Tuopanjärvi only the length of the paired fins differed and in Lake Harkkojärvi no differences were found. Taken together, these results suggest that inter and intrapopulation morphological differences are probably highly dependent on different biotic factors (i.e. predation risk, resource availability and competition). Spatial and temporal variations in these factors may have a great effect on body morphology of P. fluviatilis.
Retention of Panjet‐applied alcian blue by cyprinids
Authors: Bolland J. D. , Cowx I. G. , Lucas M. C.
Published: March 2010

Panjet‐applied alcian blue did not produce a reliable long‐term (> 5 months) mark. Average time to mark loss was 9·5 months for chub Leuciscus cephalus, 6·0 months for dace Leuciscus leuciscus and 11·1 months for roach Rutilus rutilus. Growth rate did not influence retention.
Rapid digestion of fish prey by the highly invasive ‘detritivore’Oreochromis mossambicus
Authors: Doupé R. G. , Knott M. J.
Published: March 2010

Stomach residence time was tested over 24 h in three size classes of Oreochromis mossambicus using juvenile Lates calcarifer. In all 63 observations, the fish prey was digested within 24 h of consumption and most probably within 1 h, suggesting a need to re‐evaluate the trophic status and potential effects of this highly invasive species.
Phylogenetic relationships of the newly described species Chondrostoma olisiponensis (Teleostei: Cyprinidae)
Authors: Gante H. F. , Santos C. D. , Alves M. J.
Published: March 2010

Phylogenies were generated using mitochondrial cytochrome b and nuclear ß‐actin gene DNA sequences to infer the phylogenetic relationships of the newly described Chondrostoma olisiponensis. Results indicate that the species is monophyletic with species of the lemmingii‐group in mtDNA phylogenies, while it is monophyletic with species of the arcasii‐group in the nuclear ß‐actin trees. This is in agreement with the morphological resemblance of C. olisiponensis to both species groups. Results from nuclear but not mitochondrial DNA indicate that one population could be currently hybridizing with sympatric Chondrostoma lusitanicum. Based on a relaxed clock calibration of cytochrome b, it is estimated that C. olisiponensis split 12·5–7·9 million years ago (middle–upper Miocene) from its most recent ancestor, which coincides with a period of endorrheism in the Iberian Peninsula.
Effect of temperature and roach Rutilus rutilus group size on swimming speed and prey capture rate of perch Perca fluviatilis and R. rutilus
Authors: Linløkken A. N. , Bergman E. , Greenberg L.
Published: March 2010

Effects of temperature and group size of roach Rutilus rutilus on foraging behaviour of perch Perca fluviatilis and R. rutilus were tested in two laboratory experiments. A temperature experiment with P. fluviatilis and R. rutilus in aquaria (with either one P. fluviatilis or two R. rutilus) was tested at five temperatures: 4, 8, 12, 16 and 20° C, and showed that P. fluviatilis had a lower swimming speed and capture rate than R. rutilus, especially at 4 and 8° C. The effect of group size was tested at four R. rutilus abundances: 0, 2, 4 and 6, all at 16° C, and revealed that swimming speed and capture rate of P. fluviatilis were lowest at the highest R. rutilus abundance, whereas R. rutilus was relatively unaffected. Perca fluviatilis occupied positions closer to the bottom than R. rutilus, especially when feeding, and this tendency was reinforced at the highest roach abundance.
Are morphometric indices accurate indicators of stored energy in herring Clupea harengus?
Authors: Davidson D. , Marshall C. T.
Published: March 2010

The accuracy of the morphometric indices Fulton's K, somatic K and relative condition factor, Kn, as measures of individual North Sea herring Clupea harengus muscle fat content was investigated using the Distell Fish Fat meter. The accuracy of fat‐meter readings from an individual fish was validated by comparison with Soxhlet extraction analysis. The studies conducted demonstrated that Fulton's K is not consistently or strongly correlated with individual C. harengus muscle fat content, as defined by the fat‐meter estimates. The study shows that somatic K and Kn may be better indices of individual North Sea C. harengus muscle fat content than Fulton's K. These morphometric indices, however, should only be used after prior validation against a more direct measure of fat content.