bluuebunny/crossref_metadata_2025 huggingface dataset:
A proposal for in vitro/GFR molecular erythema action spectrum
Authors: de Souza João A. V. , Lorenzini Fabiane , Rizzatti Mara R.
Published: August 2008

We propose an erythema action spectrum based on experimental molecular measurements named molecular erythema action spectrum or in vitro/GFR, where the acronym GFR represents our research group name, Grupo de Física das Radiaçöes. The in vitro methodology was developed by using a derma tissue simulator (TSD), as a radiation protection shield, and monochromatic ultraviolet (UV) sources of 254, 310, 365, 380, and 400 nm. The irradiance from each source was monitored through spectroradiometry in order to obtain the exposure dose over a period of time. Changes in the chemical structure were monitored by Fourier transform infrared spectroscopy (FTIR) and UV and visible spectroscopy (UV-vis). The samples were analyzed by UV-vis at each 200 up to 1000 J/m2 and at each 400 up to 2000 J/m2. FTIR was performed only for samples exposed to a maximum dose of 2000 J/m2. The in vitro action parameters were obtained by considering the redshift revealed through UV-vis analysis, as being the molecular quantification of minimal erythema, and the chemical bond rupture of TSD molecules associated with erythema, revealed through FTIR. The in vitro/GFR action spectrum shows that UV-A and UV-B radiation are equally responsible for the damage observed in TSD. When this proposal was compared to the CIE erythema action spectrum from ISO [ISO17166 CIE S 007/E, Erythema Reference Action Spectrum and Standard Erythema Dose (CIE Central Bureau, Austria, 1998)], similarities could be observed in wavelengths less than 280 nm in UV-B region. However, for wavelengths higher than 300 nm, the efficiency of this radiation to induce damage, mainly in the UV-A part, was much higher than predicted in CIE model. The increasing concern on UV-A radiation, assumed to be as responsible as UV-B for inducing most of the already observed skin injuries, may be better understood when observing the experimental model presented in in vitro/GFR action spectrum.
A single input-single output coupled microresonator array for the detection and identification of multiple analytes
Authors: DeMartini Barry E. , Rhoads Jeffrey F. , Zielke Mark A. , Owen Kyle G. , Shaw Steven W. , Turner Kimberly L.
Published: August 2008

This work reports the experimental demonstration of single input-single output, multianalyte detection and identification using a coupled array of microresonators. A prototype sensor with four frequency-mistuned microbeam sensors, each coupled to a common shuttle mass resonator, is presented. Tailored localized modes of vibration in this coupled system are exploited to embed all requisite resonance shift information into the response of the common shuttle. Four standard polymers are applied to the microbeams to functionalize them for vapor detection. Toluene and methanol vapors, as well as toluene/methanol mixtures, are detected and identified using a single input signal and a single output signal.
A new diagnostic of the plasma density profile near the edge transport barrier from measurements of the radial profile of the Hα line intensity
Authors: Voronov G. S.
Published: August 2008

An edge transport barrier is now one of the most important subjects of controlled fusion research. The edge transport barrier is located in the plasma region where hydrogen atoms readily penetrate, so the intensity of the Hα (Dα) line is high enough. A new diagnostic method uses the well-known property of hydrogen atoms that the ratio of the ionization rate Si to the excitation rate Sv for the Hα line is nearly constant over a wide range of plasma temperatures and densities. An expression has been derived that relates the radial profiles of the plasma density and Hα intensity. The use of charge coupled device detectors makes it possible to measure the radial profile of Hα line intensity with a resolution ∼0.1cm; a high intensity of the Hα line ensures a high time resolution ∼1ms. A high resolution is thus achieved for the density profile calculated from the Hα intensity profile. The method was tested when studying the plasma density profile in the region of edge transport barrier in the L-2M stellarator. It has been shown that the density gradient varies during the barrier formation and that a fine structure of the density profile correlates with a character of the plasma transport near resonance magnetic flux surfaces.
The origin of the hole injection improvements at indium tin oxide/molybdenum trioxide/N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl- 4,4′-diamine interfaces
Authors: Lee Hyunbok , Cho Sang Wan , Han Kyul , Jeon Pyung Eun , Whang Chung-Nam , Jeong Kwangho , Cho Kwanghee , Yi Yeonjin
Published: August 2008

We investigated the interfacial electronic structures of indium tin oxide (ITO)/molybdenum trioxide (MoO3)/N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) using in situ ultraviolet and x-ray photoemission spectroscopy to understand the origin of hole injection improvements in organic light-emitting devices (OLEDs). Inserting a MoO3 layer between ITO and NPB, the hole injection barrier was remarkably reduced. Moreover, a gap state in the band gap of NPB was found which assisted the Ohmic hole injection at the interface. The hole injection barrier lowering and Ohmic injection explain why the OLED in combination with MoO3 showed improved performance.
Investigations of dopants introduction in hafnia: Electronic properties, diffusion, and their role on the gate leakage current
Authors: Cuny Valérie , Richard Nicolas
Published: August 2008

To understand the role of dopants in the electronic properties of monoclinic hafnium dioxide, we have performed first-principles simulations using density functional theory. The structure, ionization energies, electron affinities, formation energies, and activation energies for fluorine and nitrogen atoms in different charge states are obtained. Compared to nitrogen incorporation, we observe that fluorine introduction improves more efficiently the dioxide performances, removing the band gap state induced by oxygen vacancy. Our results suggest that fluorine is the best passivant of oxygen vacancies and that its incorporation can be used to decrease the gate leakage current through hafnia-based devices.
Microstructure and piezoelectric properties of the CuO-added (Na0.5K0.5)(Nb0.97Sb0.03)O3 lead-free piezoelectric ceramics
Authors: Park Hwi-Yeol , Seo In-Tae , Choi Min-Kyu , Nahm Sahn , Lee Hyeung-Gyu , Kang Hyung-Won , Choi Byung-Hyun
Published: August 2008

The presence of the Sb5+ ion increased the piezoelectric properties of the (Na0.5K0.5)NbO3 (NKN) ceramics by enhancing the poling state as identified by the increased phase angle (θ). The increased θ value was explained by the increased ferroelectricity due to the large electronegativity of the Sb5+ ion and the increased off centering of the cation due to the small ionic size of the Sb5+ ion. The (Na0.5K0.5)(Nb0.97Sb0.03)O3[NK(N0.97S0.03)] ceramics containing CuO were well sintered even at 960 °C. A small amount of the Cu2+ ions was incorporated into the matrix of the NK(N0.97S0.03) ceramic and behaved as a hardener. The kp, Qm, d33, and ε3T/ε0 values of the CuO-added NK(N0.97S0.03) ceramics were much higher than those of the CuO-added NKN ceramics due to the Sb5+ ion’s enhancement of the piezoelectric properties by increasing the poling state of the specimens. The high piezoelectric properties of kp=0.41, Qm=1333, d33=111 pC/N, and ε3T/ε0=324 were obtained from the 2.0 mol % CuO-added NK(N0.97S0.03) ceramics sintered at 960 °C for 8 h.
Preparation of freestanding germanium nanocrystals by ultrasonic aerosol pyrolysis
Authors: Stoldt Conrad R. , Haag Michael A. , Larsen Brian A.
Published: August 2008

This letter reports a synthetic route adaptable for the continuous, large-scale production of germanium (Ge) nanocrystals for emerging electronic and optoelectronic applications. Using an ultrasonic aerosol pyrolysis approach, diamond cubic Ge nanocrystals with dense, spherical morphologies and sizes ranging from 3to14nm are synthesized at 700°C from an ultrasonically generated aerosol of tetrapropylgermane (TPG) precursor and toluene solvent. The ultimate crystal size demonstrates a near linear relationship within the range of TPG concentrations investigated, while the shape of the measured size distributions predicts multiple particle formation mechanisms during aerosol decomposition and condensation.
Magnetoresistance near the ferromagnetic-paramagnetic phase transition in magnetic semiconductors
Authors: Brodowska B. , Kuryliszyn-Kudelska I. , Wojtowicz T. , Arciszewska M. , Dobrowolski W. , Slynko E. I. , Slynko V. E. , Liu X. , Furdyna J. K.
Published: August 2008

Magnetic and transport properties of ferromagnetic semiconductors (FMSs) near the ferromagnetic-paramagnetic phase transition were studied in two classes of FMSs: in the III–V-based In1−xMnxSb and Ga1−xMnxAs epitaxial films and in IV–VI-based Sn1−xMnxTe and Sn1−x−yMnxEryTe alloys in bulk crystal form. Magnetoresistance data for both FMS classes are in excellent agreement with the theory of Majumdar and Littlewood, indicating that near the Curie temperature, magnetic fluctuations play a key role as scattering centers. These results also show that the Majumdar–Littlewood model can be applied to magnetically very dilute systems.
Enzyme-based lactic acid detection using AlGaN∕GaN high electron mobility transistors with ZnO nanorods grown on the gate region
Authors: Chu B. H. , Kang B. S. , Ren F. , Chang C. Y. , Wang Y. L. , Pearton S. J. , Glushakov A. V. , Dennis D. M. , Johnson J. W. , Rajagopal P. , Roberts J. C. , Piner E. L. , Linthicum K. J.
Published: August 2008

The detection of lactic acid with ZnO nanorod-gated AlGaN∕GaN high electron mobility transistors (HEMTs) was demonstrated. The array of ZnO nanorods provided a large effective surface area with a high surface-to-volume ratio and a favorable environment for the immobilization of lactate oxidase. The HEMT drain-source current showed a rapid response when various concentrations of lactic acid solutions were introduced to the gate area of the HEMT sensor. The HEMT could detect lactic acid concentrations from 167nM to 139μM. Our results show that portable, fast response, and wireless-based lactic acid detectors can be realized with AlGaN∕GaN HEMT based sensors.
Terahertz generation in an actively controlled femtosecond enhancement cavity
Authors: Theuer M. , Molter D. , Maki K. , Otani C. , L’huillier J. A. , Beigang R.
Published: August 2008

We report on terahertz generation by Cherenkov-type optical rectification in lithium niobate using an actively controlled femtosecond pumped enhancement cavity. In this way a much higher pump power is available inside the cavity and an increased terahertz output power is obtained. The advantages of terahertz generation in the Cherenkov geometry are verified by comparing it with other types of emitters by means of electro-optical detection as well as by bolometer measurements.
The multipole resonance probe: A concept for simultaneous determination of plasma density, electron temperature, and collision rate in low-pressure plasmas
Authors: Lapke M. , Mussenbrock T. , Brinkmann R. P.
Published: August 2008

A diagnostic concept is presented which enables the simultaneous determination of plasma density, electron temperature, and collision rate in low-pressure gas discharges. The proposed method utilizes a radio-frequency driven probe of particular spherical design which is immersed in the plasma to excite a family of spatially bounded surface resonances. An analysis of the measured absorption spectrum S(ω) of the probe provides information on the distribution of the plasma in its vicinity, from which the values of the plasma parameters can be inferred. In its simplest realization, the probe consists of two dielectrically shielded, conducting hemispheres, which are symmetrically driven by an radio-frequency source, and the excited resonances can be classified as multipole fields, which allows an analytical evaluation of the measured signal. The proposed method is robust, calibration free, economical, and can be used for ideal and reactive plasmas alike.
Highly efficient diffractive reflector using microgratings for reflective display
Authors: Kim Jin-Hwan , Yu Jae-Ho , Cheong Byoung-Ho , Choi Yoon-Sun , Choi Hwan-Young
Published: August 2008

A highly efficient diffractive reflector with a rhombus shape angular distribution of reflected light for mobile liquid crystal display is developed. The fabricated diffractive reflector shows enhanced reflectance two times higher than the conventional bumpy reflector. The diffractive reflector composed of 25 surface relief microgratings is fabricated by photoresist patterning and metal deposition. The angular distribution of light that is reflected off the diffractive reflector is measured under specula illumination and diffusive illumination. The sufficient controllability of the angular distribution of the reflected light by the specific design of the period, orientation, and depth of each micrograting is shown.
High-efficiency monochrome organic light emitting diodes employing enhanced microcavities
Authors: Meerheim Rico , Nitsche Robert , Leo Karl
Published: August 2008

We demonstrate enhanced light outcoupling from bottom emitting monochrome high-efficiency red, green, and blue organic light emitting diodes by adding silver layers on the indium tin oxide (ITO) anode. The devices contain the phosphorescent emitting dyes tris(2-phenylpyridine)iridium and iridium(III)bis[2-methyldibenzo-(f, h)quinoxaline](acetylacetonate), and the blue singlet emitter 2,2′,7,7′-tetrakis 2,2-(diphenylvinyl)spiro-9,9′-bifluorene. We follow the p-i-n doping concept to increase the power efficiencies. We reach 81 lm/W for red, 101 lm/W for green, and 4.0 lm/W for blue color. These efficiencies are improved by up to a factor of 2.3 compared to standard ITO devices, which we attribute to microcavity amplification between the cathode and the Ag layer.
Improvement of quantum efficiency of photomultiplier tubes by humidity controlled coatings based on porous polymer structures
Authors: Körstgens V. , Hsu C.-C. , Paneque D. , Wiedersich J. , Müller-Buschbaum P.
Published: August 2008

Based on spin coating in humidity controlled environment an extremely simple deposition process is established which allows convenient and reproducible coating of photomultiplier tubes (PMTs) to achieve an improvement in photon sensitivity and thereby a higher quantum efficiency. The coatings consisting of a blend of polyacrylate based copolymer with p-terphenyl are obtained from dichloromethane solutions. On the curved PMTs structures due to crystallization of p-terphenyl superposed with pores in the copolymer matrix are present. On flat substrates coatings established under identical conditions exhibit the same porous structure. The origin of the obtained structures is discussed in context of breath figures.
X-ray photoelectron spectroscopic study of Ge2Sb2Te5 etched by fluorocarbon inductively coupled plasmas
Authors: Kang S.-K. , Oh J. S. , Park B. J. , Kim S. W. , Lim J. T. , Yeom G. Y. , Kang C. J. , Min G. J.
Published: August 2008

X-ray photoelectron spectroscopy was used to determine the level of surface fluorination damage of Ge2Sb2Te5 (GST) etched by fluorocarbon gases at different F/C ratios. When blank GST was etched, the gas with a higher F/C ratio produced a thinner C–F polymer on the etched surface but fluorinated Ge, Sb, and Te compounds were observed in the remaining GST. When the sidewall of the etched GST features was investigated, a thicker fluorinated layer was observed on the GST sidewall etched by the higher F/C ratio gas, indicating more fluorination due to the difficulty in preventing F diffusion into the GST through the thinner C–F layer.
X-ray diffraction study of polycrystalline BiFeO3 thin films under electric field
Authors: Nakashima Seiji , Sakata Osami , Nakamura Yoshitaka , Kanashima Takeshi , Funakubo Hiroshi , Okuyama Masanori
Published: August 2008

Diffraction measurements using 12.4keV x-ray of synchrotron radiation have been performed in (001)pc- and (110)pc-oriented polycrystalline 350-nm-thick BiFeO3 thin films on a Pt∕TiO2∕SiO2∕Si substrate under electric field in air at RT. Unipolar rectangular pulse voltages having a 150ns width and a 804.09ns period have been applied to BiFeO3 with a Pt top electrode. A diffraction peak of the (001)pc [(110)pc] plane shifts from 14.602° (20.520°) to 14.588 (20.505°) due to piezoelectric response when a 12V (11V) pulse is applied. Piezoelectric constants (d33) of (001)pc-oriented and (110)pc-oriented domains estimated from these peak shifts are 27.8 and 26.4pm∕V, respectively.
Carbon nanotubes on carbon fabrics for flexible field emitter arrays
Authors: Suzuki Kenichi , Matsumoto Hidetoshi , Minagawa Mie , Tanioka Akihiko , Hayashi Yasuhiko , Fukuzono Kazuyuki , Amaratunga Gehan A. J.
Published: August 2008

Flexible carbon fabrics (CFs) prepared by electrospray deposition were used for the substrate of carbon nanotube (CNT) field emitter arrays. CNTs were grown on the CFs by chemical vapor deposition. The CNT field emitter arrays on CFs produced a higher current density at a lower turn-on voltage compared to ones on a Si substrate.
Synthesis of horizontally aligned ZnO nanowires localized at terrace edges and application for high sensitivity gas sensor
Authors: Son J. Y. , Lim S. J. , Cho J. H. , Seong W. K. , Kim Hyungjun
Published: August 2008

We developed step edge decoration method for the fabrication of semiconductor ZnO nanodots and nanowires using pulsed laser deposition. We synthesized high quality ZnO nanowires with the small diameter of about 20nm and the uniform interval of about 80nm between each nanowire, which has a simple structure for the formation of contact electrodes. The ZnO nanowire-based sensor was prepared only with the simple process of a gold electrode formation. The ZnO nanowire-based sensor exhibited the high surface-to-volume ratio of 58.6μm−1 and the significantly high sensitivity of about 10 even for the low ethanol concentration of 0.2ppm.
Nearly intrinsic exciton lifetimes in single twin-free GaAs∕AlGaAs core-shell nanowire heterostructures
Authors: Perera S. , Fickenscher M. A. , Jackson H. E. , Smith L. M. , Yarrison-Rice J. M. , Joyce H. J. , Gao Q. , Tan H. H. , Jagadish C. , Zhang X. , Zou J.
Published: August 2008

CW and time-resolved photoluminescence measurements are used to investigate exciton recombination dynamics in GaAs∕AlGaAs heterostructure nanowires grown with a recently developed technique which minimizes twinning. A thin capping layer is deposited to eliminate the possibility of oxidation of the AlGaAs shell as a source of oxygen defects in the GaAs core. We observe exciton lifetimes of ∼1ns, comparable to high quality two-dimensional double heterostructures. These GaAs nanowires allow one to observe state filling and many-body effects resulting from the increased carrier densities accessible with pulsed laser excitation.
Morphology and flexibility of graphene and few-layer graphene on various substrates
Authors: Stöberl U. , Wurstbauer U. , Wegscheider W. , Weiss D. , Eroms J.
Published: August 2008

We report on detailed microscopy studies of graphene and few-layer graphene produced by mechanical exfoliation on various semiconducting substrates. We demonstrate the possibility to prepare and analyze graphene on (001)-GaAs, manganese p-doped (001)-GaAs, and InGaAs substrates. The morphology of graphene on these substrates was investigated by scanning electron and atomic force microscopies and compared to layers on SiO2. It was found that graphene sheets strongly follow the texture of the sustaining substrates independent on doping, polarity, or roughness. Furthermore resist residues exist on top of graphene after a lithographic step. The obtained results provide the opportunity to research the graphene-substrate interactions.
Atomic resolution study of the interfacial bonding at Si3N4/CeO2−δ grain boundaries
Authors: Walkosz W. , Klie R. F. , Öğüt S. , Borisevich A. , Becher P. F. , Pennycook S. J. , Idrobo J. C.
Published: August 2008

Using a combination of atomic-resolution Z-contrast imaging and electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope, we examine the atomic and electronic structures at the interface between Si3N4 (101¯0) and CeO2−d intergranular film (IGF). Ce atoms are observed to segregate to the interface in a two-layer periodic arrangement, which is significantly different from the structure observed in a previous study. Our EELS experiments show (i) oxygen in direct contact with the terminating Si3N4 open-ring structures, (ii) a change in the Ce valence from a nominal oxidation state of +3 to almost +4 moving from the interface into the IGF, and (iii) a uniform concentration of Si in the film.
Measuring Environmental Externality Spillovers through Choice Modelling
Authors: Concu Giovanni B
Published: August 2008

This paper illustrates the design and implementation of a choice modelling experiment to determine the spatial distribution of environmental benefits of Kings Park (Western Australia). The objective is to understand which environmental change produces benefit spillovers, and whether this information can help to determine the appropriate form of funding for conservation policies. Results indicate that distance effects vary across the choice attributes, and can take very complex forms, according to the use-value/non-use-value ratio implicit in each attribute. For policy purposes, the results suggest that funding for the park should be a mix of local, state, and federal resources.
Does Venture Capital Investment Really Require Spatial Proximity? An Empirical Investigation
Authors: Fritsch Michael , Schilder Dirk
Published: August 2008

We examine the role of spatial proximity for venture capital (VC) investments in Germany. The main database is a survey of seventy-five personal interviews with representatives of different types of financial institutions. The analysis shows that spatial proximity is much less important for VC investments than is often believed. The results indicate that telecommunication cannot be regarded as a means of overcoming the problems of geographical distance. We find that VC suppliers frequently syndicate investments in distant portfolio firms with partners who are more closely located. The age of the portfolio firm does not affect the importance of spatial proximity. On the whole, regional proximity is not a dominant factor in VC partnerships.
The Emotional Economy of Housing
Authors: Christie Hazel , Smith Susan J , Munro Moira
Published: August 2008

This paper offers an interpretation of the role of emotions in animating housing markets which complements more traditional economic and behavioural studies of locally based house-price inflation. Looking to debates within social psychology and cultural studies we suggest that emotions permeate the materiality and meaning of housing markets as well as the experience of individuals acting within them. Drawing on qualitative interviews conducted in Edinburgh, with households who bought in a rising market, we argue that housing transactions are emotional as well as economic affairs. We reconsider the fears that underpin what might appear to be ‘irrational exuberance’ and we argue that housing markets are propelled by a search for returns on emotional as well as financial investments.
Interocular Transfer of a Rotational Motion Aftereffect as a Function of Eccentricity
Authors: Grove Philip M , Ashida Hiroshi , Kaneko Hirohiko , Ono Hiroshi
Published: August 2008

In previous psychophysical investigations it has been reported that the angular extent over which the human visual field is served by binocular neurons in the visual cortex is limited to the central 40°. However, these reports have been primarily based on data collected with static stimuli. Here we extend this investigation to include dynamic stimuli. Interocular transfer of the rotary motion aftereffect (rMAE) was measured for three stimulus diameters: 5, 30, and 62 deg. Interocular transfer, expressed as a percentage of monocular adapt/test rMAE duration was significantly reduced for stimulus diameter of 62 deg relative to 30 and 5 deg diameters. Nevertheless, interocular transfer durations still comprised a significant percentage of same-eye adapt/test durations (46.9%), comparable to previous reports of transfer MAE durations in near-central vision. The spatial extent of binocular interaction is likely stimulus specific and is still appreciable in the far periphery for complex-motion stimuli.
Reducing Contrast Makes Speeds in a Video-Based Driving Simulator Harder to Discriminate as Well as Making Them Appear Slower
Authors: Horswill Mark S , Plooy Annaliese M
Published: August 2008

We investigated the effect of reducing image contrast on speed perception using a video-based driving simulator in which participants viewed pairs of scenes and were asked to judge whether the second scene was faster or slower than the first scene. We predicted two outcomes: (i) that vehicle speeds would become harder to discriminate, and (ii) that vehicle speeds would appear slower. There is previous evidence confirming the latter prediction in a less realistic computer-based driving simulation, but none demonstrating the former. Our results supported both predictions, each of which may have traffic-safety implications when reduced-contrast conditions are experienced in real life, such as with fog or when the driver has cataracts.
Representation or Context as a Cognitive Strategy in Colour Constancy?
Authors: Lin Ta-Wei , Sun Chun-Wang
Published: August 2008

If an identification task with colour constancy as its objective is carried out under drastically changing illumination, do people rely mainly on colour information or do they rely on other sources of information? This question suggested two hypotheses for testing: (i) context hypothesis: people rely mainly on colour information (spectral reflectance or illumination chromaticity) to achieve colour constancy; (ii) representation hypothesis: people rely mainly on all other clues associated with colour to achieve colour constancy, including form information (any shape elements) and space information (spatial coordinates or spatial correlation). Experiment 1 showed that form information was readily associated with colour information to produce implicit representation. This gave the best colour-constancy performance (95.72%) and the fastest processing speed, so it probably used a top–down process. However, it was also prone to error owing to assumptions. Space information was not readily associated with colour information so colour-constancy performance was halved (48.73%) and processing time doubled. When the subject was deprived of both information sources and only given colour information, this resulted in the longest reaction times and the worst colour-constancy performance (41.38%). These results clearly support the representation hypothesis rather than the context hypothesis. When all three clues were available at the same time, the order of preference was: symbol, location, then colour. Experiment 2 showed that when form information was the main clue, colour-constancy performance was conceptually driven and processed more quickly; this supports the representation hypothesis. However, when form information was not used, colour constancy was data-driven, processed more slowly, and achieved an inferior identification rate overall; this supports the context hypothesis.
Thermal acclimation of respiration but not photosynthesis in Pinus radiata
Authors: Ow Lai Fern , Whitehead David , Walcroft Adrian S. , Turnbull Matthew H.
Published: August 2008

Pinus radiata L. were grown in climate-controlled cabinets under three night/day temperature treatments, and transferred between treatments to mimic changes in growth temperature. The objective was to determine the extent to which dark respiration and photosynthesis in pre-existing and new needles acclimate to changes in growth temperatures. We also assessed whether needle nitrogen influenced the potential for photosynthetic and respiratory acclimation, and further assessed if short-term (instantaneous, measured over a few hours) respiratory responses are accurate predictors of long-term (acclimated, achieved in days–weeks) responses of respiration to changing temperature. Results show that respiration displayed considerable potential for acclimation. Cold and warm transfers resulted in some acclimation of respiration in pre-existing needles, but full acclimation was displayed only in new needles formed at the new growth temperature. Short-term respiratory responses were poor predictors of the long-term response of respiration due to acclimation. There was no evidence that photosynthesis in pre-existing or new needles acclimated to changes in growth temperature. N status of leaves had little impact on the extent of acclimation. Collectively, our results indicate that there is little likelihood that respiration would be significantly stimulated in this species as night temperatures increase over the range of 10–20°C, but that inclusion of temperature acclimation of respiration would in fact lead to a shift in the balance between photosynthesis and respiration in favour of carbon uptake.
Using poultry litter biochars as soil amendments
Authors: Chan K. Y. , Van Zwieten L. , Meszaros I. , Downie A. , Joseph S.
Published: August 2008

Despite the recent interest in biochars as soil amendments for improving soil quality and increasing soil carbon sequestration, there is inadequate knowledge on the soil amendment properties of these materials produced from different feed stocks and under different pyrolysis conditions. This is particularly true for biochars produced from animal origins. Two biochars produced from poultry litter under different conditions were tested in a pot trial by assessing the yield of radish (Raphanus sativus var. Long Scarlet) as well as the soil quality of a hardsetting Chromosol (Alfisol). Four rates of biochar (0, 10, 25, and 50 t/ha), with and without nitrogen application (100 kg N/ha) were investigated. Both biochars, without N fertiliser, produced similar increases in dry matter yield of radish, which were detectable at the lowest application rate, 10 t/ha. The yield increase (%), compared with the unamended control rose from 42% at 10 t/ha to 96% at 50 t/ha of biochar application. The yield increases can be attributed largely to the ability of these biochars to increase N availability. Significant additional yield increases, in excess of that due to N fertiliser alone, were observed when N fertiliser was applied together with the biochars, highlighting the other beneficial effects of these biochars. In this regard, the non activated poultry litter biochar produced at lower temperature (450°C) was more effective than the activated biochar produced at higher temperature (550°C), probably due to higher available P content. Biochar addition to the hardsetting soil resulted in significant but different changes in soil chemical and physical properties, including increases in C, N, pH, and available P, but reduction in soil strength. These different effects of the 2 different biochars can be related to their different characteristics. Significantly different changes in soil biology in terms of microbial biomass and earthworm preference properties were also observed between the 2 biochars, but the underlying mechanisms require further research. Our research highlights the importance of feedstock and process conditions during pyrolysis on the properties and, hence, soil amendment values of biochars.
Evaluation of the composite burn index for assessing fire severity in Alaskan black spruce forests
Authors: Kasischke Eric S. , Turetsky Merritt R. , Ottmar Roger D. , French Nancy H. F. , Hoy Elizabeth E. , Kane Evan S.
Published: August 2008

We evaluated the utility of the composite burn index (CBI) for estimating fire severity in Alaskan black spruce forests by comparing data from 81 plots located in 2004 and 2005 fire events. We collected data to estimate the CBI and quantify crown damage, percent of trees standing after the fire, depth of the organic layer remaining after the fire, depth of burning in the surface organic layer (absolute and relative), and the substrate layer exposed by the fire. To estimate pre-fire organic layer depth, we collected data in 15 unburned stands to develop relationships between total organic layer depth and measures of the adventitious root depth above mineral soil and below the surface of the organic layer. We validated this algorithm using data collected in 17 burned stands where pre-fire organic layer depth had been measured. The average total CBI value in the black spruce stands was 2.46, with most of the variation a result of differences in the CBI observed for the substrate layer. While a quadratic equation using the substrate component of CBI was a relatively strong predictor of mineral soil exposure as a result of fire (R2 = 0.61, P < 0.0001, F = 60.3), low correlations were found between the other measures of fire severity and the CBI (R2 = 0.00–0.37). These results indicate that the CBI approach has limited potential for quantifying fire severity in these ecosystems, in particular organic layer consumption, which is an important factor to understand how ecosystems will respond to changing climate and fire regimes in northern regions.
Using Landsat data to assess fire and burn severity in the North American boreal forest region: an overview and summary of results
Authors: French Nancy H. F. , Kasischke Eric S. , Hall Ronald J. , Murphy Karen A. , Verbyla David L. , Hoy Elizabeth E. , Allen Jennifer L.
Published: August 2008

There has been considerable interest in the recent literature regarding the assessment of post-fire effects on forested areas within the North American boreal forest. Assessing the physical and ecological effects of fire in boreal forests has far-reaching implications for a variety of ecosystem processes – such as post-fire forest succession – and land management decisions. The present paper reviews past assessments and the studies presented in this special issue that have largely been based on the Composite Burn Index and differenced Normalized Burn Ratio (dNBR). Results from relating and mapping fire/burn severity within the boreal region have been variable, and are likely attributed, in part, to the wide variability in vegetation and terrain conditions that are characteristic of the region. Satellite remote sensing of post-fire effects alone without proper field calibration should be avoided. A sampling approach combining field and image values of burn condition is necessary for successful mapping of fire/burn severity. Satellite-based assessments of fire/burn severity, and in particular dNBR and related indices, need to be used judiciously and assessed for appropriateness based on the users’ need. Issues unique to high latitudes also need to be considered when using satellite-derived information in the boreal forest region.
Seasonal and topographic effects on estimating fire severity from Landsat TM/ETM+ data
Authors: Verbyla David L. , Kasischke Eric S. , Hoy Elizabeth E.
Published: August 2008

The maximum solar elevation is typically less than 50 degrees in the Alaskan boreal region and solar elevation varies substantially during the growing season. Because of the relatively low solar elevation at boreal latitudes, the effect of topography on spectral reflectance can influence fire severity indices derived from remotely sensed data. We used Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) data to test the effect of changing solar elevation and topography on the Normalized Burn Ratio (NBR) and the differenced Normalized Burn Ratio (dNBR). When a time series of unburned pixels from black spruce forests was examined, we found that NBR values consistently decreased from June through September. At the stand level, dNBR-derived values from similar unburned and burned black spruce stands were substantially higher from September imagery relative to July or August imagery. Within the Boundary burn, we found mean post-fire NBR to consistently vary owing to topographic control of potential solar radiation. To minimise spectral response due to topographic control of vegetation and fire severity, we computed a dNBR using images from August and September immediately after a June–July wildfire. There was a negative bias in remotely sensed fire severity estimates as potential solar radiation decreased owing to topography. Thus fire severity would be underestimated for stands in valley bottoms dominated by topographic shading or on steep north-facing slopes oriented away from incoming solar radiation. This is especially important because highly flammable black spruce stands typically occur on such sites. We demonstrate the effect of changing pre- and post-fire image dates on fire severity estimates by using a fixed NBR threshold defining ‘high severity’. The actual fire severity was constant, but owing to changes in phenology and solar elevation, ‘high severity’ pixels within a burn ranged from 56 to 76%. Because spectral reflectance values vary substantially as solar elevation and plant phenology change, the use of reflectance-based indices to assess trends in burn severity across regions or years may be especially difficult in high-latitude areas such as the Alaskan boreal forest.
Evaluating the potential of Landsat TM/ETM+ imagery for assessing fire severity in Alaskan black spruce forests
Authors: Hoy Elizabeth E. , French Nancy H. F. , Turetsky Merritt R. , Trigg Simon N. , Kasischke Eric S.
Published: August 2008

Satellite remotely sensed data of fire disturbance offers important information; however, current methods to study fire severity may need modifications for boreal regions. We assessed the potential of the differenced Normalized Burn Ratio (dNBR) and other spectroscopic indices and image transforms derived from Landsat TM/ETM+ data for mapping fire severity in Alaskan black spruce forests (Picea mariana) using ground measures of severity from 55 plots located in two fire events. The analysis yielded low correlations between the satellite and field measures of severity, with the highest correlation (R2adjusted = 0.52, P < 0.0001) between the dNBR and the composite burn index being lower than those found in similar studies in forests in the conterminous USA. Correlations improved using a ratio of two Landsat shortwave infrared bands (Band 7/Band 5). Overall, the satellite fire severity indices and transformations were more highly correlated with measures of canopy-layer fire severity than ground-layer fire severity. High levels of fire severity present in the fire events, deep organic soils, varied topography of the boreal region, and variations in solar elevation angle may account for the low correlations, and illustrate the challenges faced in developing approaches to map fire and burn severity in high northern latitude regions.
Retinoic acid-stimulated sequential phosphorylation, PML recruitment, and SUMOylation of nuclear receptor TR2 to suppress Oct4 expression
Authors: Gupta Pawan , Ho Ping-Chih , Huq MD Mostaqul , Ha Sung Gil , Park Sung Wook , Khan Amjad Ali , Tsai Nien-Pei , Wei Li-Na
Published: August 2008

We previously reported an intricate mechanism underlying the homeostasis of Oct4 expression in normally proliferating stem cell culture of P19, mediated by SUMOylation of orphan nuclear receptor TR2. In the present study, we identify a signaling pathway initiated from the nongenomic activity of
all-trans
retinoic acid (atRA) to stimulate complex formation of extracellular signal-regulated kinase 2 (ERK2) with its upstream kinase, mitogen-activated protein kinase kinase (MEK). The activated ERK2 phosphorylates threonine-210 (Thr-210) of TR2, stimulating its subsequent SUMOylation. Dephosphorylated TR2 recruits coactivator PCAF and functions as an activator for its target gene
Oct4
. Upon phosphorylation at Thr-210, TR2 increasingly associates with promyelocytic leukemia (PML) nuclear bodies, becomes SUMOylated, and recruits corepressor RIP140 to act as a repressor for its target,
Oct4
. To normally proliferating P19 stem cell culture, exposure to a physiological concentration of atRA triggers a rapid nongenomic signaling cascade to suppress
Oct4
gene and regulate cell proliferation.
Experimental quantum coding against qubit loss error
Authors: Lu Chao-Yang , Gao Wei-Bo , Zhang Jin , Zhou Xiao-Qi , Yang Tao , Pan Jian-Wei
Published: August 2008

The fundamental unit for quantum computing is the qubit, an isolated, controllable two-level system. However, for many proposed quantum computer architectures, especially photonic systems, the qubits can be lost or can leak out of the desired two-level systems, posing a significant obstacle for practical quantum computation. Here, we experimentally demonstrate, both in the quantum circuit model and in the one-way quantum computer model, the smallest nontrivial quantum codes to tackle this problem. In the experiment, we encode single-qubit input states into highly entangled multiparticle code words, and we test their ability to protect encoded quantum information from detected 1-qubit loss error. Our results prove in-principle the feasibility of overcoming the qubit loss error by quantum codes.
Polarized microtubule arrays in apical dendrites and axons
Authors: Kwan Alex C. , Dombeck Daniel A. , Webb Watt W.
Published: August 2008

The polarization of microtubules within neurons
in vivo
is crucial in their role of determining the directions and speeds of intracellular transport. More than a decade ago, electron microscopy studies of mature hippocampal cultures indicated that their axons contained microtubules of uniform polarity and that dendrites contained microtubules of mixed polarity. Here, we evaluated polarity distributions in native brain tissues and in cultures by using multiphoton microscopy and second-harmonic generation from microtubules. We confirmed the expected polarized microtubule arrays in axons; however, we also unexpectedly found them ubiquitously in apical dendrites of mature hippocampal CA1 and cortical layer V pyramidal neurons. Some of these organized dendritic microtubule arrays extended for >270 μm with overall polarity of >80%. Our research indicates neurite-specific and age-dependent microtubule organizations that have direct implications for neuronal cargo transport.
Tearing mode structure in the DIII-D tokamak through spectrally filtered fast visible bremsstrahlung imaging
Authors: Van Zeeland M.A. , Yu J.H. , Chu M.S. , Burrell K.H. , La Haye R.J. , Luce T.C. , Nazikian R. , Solomon W.M. , West W.P.
Published: August 2008

Time evolved measurements of the detailed 2D poloidal structure of rotating tearing modes in the DIII-D tokamak are obtained for the first time using spectrally filtered fast imaging of broadband visible bremsstrahlung emission (N
B). Measurements are made along 256 × 256 different sightlines and show excellent agreement with simulations assuming a rotating helical m/n = 2/1 island structure superimposed on the equilibrium N
B profile. The method described here is capable of imaging with high resolution the structure of coherent oscillations in the core of current and next-step fusion plasma experiments such as ITER and can be applied to virtually any mode with a finite perturbed N
B and frequency in the laboratory frame provided sufficient signal level and detector bandwidth are available.
Development of a compact toroid fuelling system for ITER
Authors: Olynyk G. , Morelli J.
Published: August 2008

A review of literature relevant to compact toroid (CT) injection is presented. A design is then developed for a repetitive-fire CT injection fuelling system for the ITER (2001) tokamak. Advantages of central over edge fuelling include plasma density control and higher deposition rates, implying lower tritium usage. The reference design offers 50 Pa m3 s−1 of 90%T/10%D fuelling. 1.29 mg CTs are injected at a rate of 50 Hz (in order to synchronize with the European power grid) and a speed of 300 km s−1. A new six-degree-of-freedom model of CT trajectory in the tokamak is developed and applied to the proposed injector design. The fueller is intended to work in parallel with the 400 Pa m3 s−1 edge gas puffing system and to replace the centrifuge pellet-injection system in the ITER (2001) reference design. Each injected CT adds only 0.68% to the plasma inventory, implying that the injection process will be non-disruptive. Power consumption will be approximately 15 MWe. The strengths of the design compared with the current pellet-injection system are highlighted.
BLogo: a tool for visualization of bias in biological sequences
Authors: Li Wencheng , Yang Bo , Liang Shaoguang , Wang Yonghua , Whiteley Chris , Cao Yicheng , Wang Xiaoning
Published: August 2008

Summary: Blogo is a web-based tool that detects and displays statistically significant position-specific sequence bias with reduced background noise. The over-represented and under-represented symbols in a particular position are shown above and below the zero line. When the sequences are in open reading frames, the background frequency of nucleotides could be calculated separately for the three positions of a codon, thus greatly reducing the background noise. The χ2-test or Fisher's exact test is used to evaluate the statistical significance of every symbol in every position and only those that are significant are highlighted in the resulting logo. The perl source code of the program is freely available and can be run locally.

Availability:  http://acephpx.cropdb.org/blogo/, http://www.bioinformatics.org/blogo/

Contact:  lwcbio@yahoo.com.cn; xnwang@21cn.net

Supplementary information:  Supplementary data are available atBioinformatics online.
Bringing Political Economy Back in
Authors: John Richard R.
Published: August 2008

Like so many of the fields that have flourished in history departments in recent years, business history has an uneasy relationship with political history. When business history first emerged in the United States as a separate field in the 1920s, its founders stressed the importance of lavishing on business records the same reverence that political historians accorded the personal papers of lawmakers. Only in this way, business historians assumed, would it be possible to convince other historians of the centrality of business leaders—and, more broadly, of economic institutions—to the making of the nation.
Rhinitis
Authors: Simon Chantal
Published: August 2008

Rhinitis describes inflammation of the nasal mucosa. Clinically, it presents with symptoms of nasal discharge, itching, sneezing and nasal blockage or congestion. Rhinitis is a very common condition, affecting more than one in five of the UK population on an ongoing basis, and can be classified into allergic, non-allergic and infective types. Infective causes of rhinitis include bacteria and viruses, such as the common cold. They are not considered further here.