bluuebunny/crossref_metadata_2025 huggingface dataset:
Origin of luminescence enhancement and quenching of europium complex in solution phase containing Ag nanoparticles
Authors: Fang Xiaona , Song Hongwei , Xie Liping , Liu Qiong , Zhang Hui , Bai Xue , Dong Biao , Wang Yu , Han Wei
Published: August 2009

Luminescence enhancement and quenching of Eu(TTA)3⋅2H2O complex in DMF (N,N-dimethylformamide) solution containing silver nanoparticles were observed, which depended on the concentrations of both europium complex and silver nanoparticles. Their origins were discussed based on absorption spectra, excitation and emission spectra, and luminescent decay dynamics. The results indicated that when the concentration of Eu complex was high enough, strong interaction among complex molecules occurred. The presence of Ag nanoparticles definitely decreased the interaction among complex molecules. In the solution containing Ag nanoparticles the electronic-dipole transition rate of D50-F72 increased due to enhanced local field surrounding Eu3+ ions, while the nonradiative transition rate from D50 decreased owing to decreased resonant energy transfer among europium complex molecules. These two factors lead to the luminescence enhancement of europium complex. As to the luminescent quenching, was attributed to absorption competition between Ag nanoparticles and europium complex at excited wavelength.
Chemical and electronic surface structure of 20%-efficient Cu(In,Ga)Se2 thin film solar cell absorbers
Authors: Bär M. , Repins I. , Contreras M. A. , Weinhardt L. , Noufi R. , Heske C.
Published: August 2009

The chemical and electronic surface structure of 20%-efficient Cu(In,Ga)Se2 thin film solar cell absorbers was investigated as a function of deposition process termination (i.e., ending the growth process in absence of either Ga or In). In addition to the expected In (Ga) enrichment, direct and inverse photoemission reveal a decreased Cu surface content and a larger surface band gap for the “In-terminated” absorber.
Changing the dielectric properties of BaTiO3 filled poly(phenylene oxide) composites by control of their structure
Authors: Jang Yong Kyun , Won Jong Chan , Yoon Ho Gyu
Published: August 2009

The dielectric properties of BaTiO3 (BT) filled poly(phenylene oxide) (PPO) composites are investigated according to their structure, which is modified by filling the matrix with PPO-encapsulated BT particles and forming the semi-interpenetrating polymer network with triallyl isocyanurate (TAIC). Polymer encapsulation is most effective in lowering the permittivity and tan δ of the composite by suppressing the interface polarization. The copolymerization effect of TAIC is ignorable for a low dielectric matrix such as PPO. However, the dielectric values of the composites with low molecular weight-sized PPO, as the matrix, are decreased significantly by TAIC due to the constrained orientation polarization of the matrix.
Measurement of the Peltier coefficient of semiconductors by lock-in thermography
Authors: Straube Hilmar , Wagner Jan-Martin , Breitenstein Otwin
Published: August 2009

Lock-in thermography is applied to image Joule heating and Peltier-type heat transport separately. Images obtained for a multicrystalline silicon solar cell are quantitatively evaluated using an integration method. The results are interpreted in terms of diffusion and electron/hole drag contributions. The approach presented is especially interesting where the thermal contact resistance to the sample is a problem and where versatility with respect to sample geometry is needed. A further advantage of the method is that it does not need any separate power or temperature calibration.
Photodissociation of NO2 in the (2) B22 state: The O(D12) dissociation channel
Authors: Wilkinson Iain , de Miranda Marcelo P. , Whitaker Benjamin J.
Published: August 2009

Direct current slice and crush velocity map imaging has been used to probe the photodissociation dynamics of nitrogen dioxide above the second dissociation limit. The paper is a companion to a previous publication [J. Chem. Phys. 128, 164318 (2008)] in which we reported results for the O(P3J)+NO(Π2Ω) adiabatic product channel. Here we examine the O(D12)+NO(Π2Ω) diabatic product channel at similar excitation energies. Using one- and two-color imaging experiments to observe the velocity distributions of state selected NO fragments and O atoms, respectively, we are able to build a detailed picture of the dissociation dynamics. We show that by combining the information obtained from velocity map imaging studies with mass-resolved resonantly enhanced multiphoton ionization spectroscopy it is possible to interpret and fully assign the NO images. By recording two-color images of the O(D12) photofragments with different polarization combinations of the pump and probe laser fields we also measure the orbital angular momentum alignment in the atomic fragment. We find that the entire O(D12) photofragment distribution is similarly aligned with most of the population in the MJ=±1 magnetic sublevels. The similarity of the fragment polarizations is interpreted as a signature of all of the O(D12) atoms being formed via the same avoided crossing. At the photolysis energy of 5.479 52 eV we find that the NO fragments are preferentially formed in v=1 and that the vibrationally excited fragments exhibit a bimodal rotational distribution. This is in contrast to the unimodal rotational profile of the NO fragments in v=0. We discuss these observations in terms of the calculated topology of the adiabatic potential energy surfaces and attribute the vibrational inversion and rotational bimodality of the v=1 fragments to the symmetric stretch and bending motion generated on excitation to the (2) B22 state.
Enhancement of carrier transport properties of BixSb2−xTe3 compounds by electrical sintering process
Authors: Liao Chien-Neng , Wu Li-Chieh
Published: August 2009

Bi x Sb 2 − x Te 3 (x=0.4 and 0.5) powders were pressed and sintered by passing a high-density electric current under nitrogen ambient. The electrically sintered BixSb2−xTe3 was found to have a marked increase in Hall mobility but a moderate reduction in carrier density. We propose that electric-current induced atomic diffusion plays an important role in modulating crystal defects in BixSb2−xTe3 compounds. The hot-pressed Bi0.4Sb1.6Te3 shows a threefold increase in ZT after electrical sintering process. With the electrical sintering approach we can preserve fine-grain microstructure, and hence low thermal conductivity of BixSb2−xTe3 with reasonable electrical resistivity and Seebeck coefficient.
Enhanced photochromism in nanostructured molybdenum trioxide films
Authors: Beydaghyan Gisia , Doiron Serge , Haché Alain , Ashrit P. V.
Published: August 2009

We present evidence of enhancement of photochromism in nanostructured thin films of molybdenum oxide fabricated by glancing angle deposition. The strong correlation of coloration response with the internal surface area of the films provides evidence of the importance of nanostructuring on the photochromic effect and the vital role played by the availability of water in the photochromic mechanism.
Dark field electron holography for quantitative strain measurements with nanometer-scale spatial resolution
Authors: Cooper David , Barnes Jean-Paul , Hartmann Jean-Michel , Béché Armand , Rouviere Jean-Luc
Published: August 2009

Strain measurements on strained SiGe specimens have been performed using dark field electron holography. By combining the excellent stability of state-of-the-art electron microscopes with careful specimen preparation we have been able to acquire two-dimensional strain maps of the layers with a spatial resolution of 5 nm, a background noise of 2×10−4, an interference width of 1500 nm, and a field of view of more than 500×500 nm2. We also show that the strain measurements are quantitative to within experimental error.
Excitonic couplings and interband energy transfer in a double-wall molecular aggregate imaged by coherent two-dimensional electronic spectroscopy
Authors: Milota F. , Sperling J. , Nemeth A. , Abramavicius D. , Mukamel S. , Kauffmann H. F.
Published: August 2009

The early stage of molecular excitonics and its quantum-kinetic dynamics in the multiband, bitubular cyanine dye aggregate C8O3 at room temperature are revealed by employing two-dimensional (2D) coherent electronic spectroscopy in the visible spectral region. The sub-20 fs measurements provide a direct look into the details of elementary electronic couplings by spreading spectroscopic transitions into two frequency axes. Correlation spectra of rephasing (kI=−k1+k2+k3) and nonrephasing (kII=+k1−k2+k3) data in emission (ω3)-absorption (ω1) 2D-frequency space image interband excitons into cross-peak signals and unveil the quantum-dissipative regime of exciton relaxation. Spectral streaking of cross peaks directly reveals interband dephasing and exciton population relaxation on the road to tube-to-tube energy transfer without making recourse to an a priori model. Theory and simulations, based on an effective multilevel scheme and a quantum-dissipative model with experimental pulse envelopes, explain the origin of the cross peaks, reveal the underlying sequences of electronic transitions, recover the streaking patterns of relaxing cross peaks along ω1, and reconstruct the space-energy pathways of electronic excitation flow.
X-ray initiation of nonthermal growth of single crystal pyramids in amorphous barium titanate
Authors: Feldman Y. , Lyahovitskaya V. , Leitus G. , Lubomirsky I. , Wachtel E. , Bushuev V. A. , Vaughan G. , Barkay Z. , Rosenberg Yu.
Published: August 2009

Nonthermal crystallization of amorphous barium titanate (BTO) was initiated by a monochromatic x-ray microbeam from a synchrotron radiation source. Following x-ray exposure, micron-sized BTO single crystals with a true square pyramid shape appeared on the surface of an amorphous BTO substrate-free film. The location and size of the areas in which crystal growth appeared fit well the x-ray microbeam path and size, respectively. A plausible mechanism of x-ray induced initiation of nonthermal crystallization in BTO is proposed. The observed phenomenon holds promise for materials engineering at nanoscale and crystallization of amorphous materials in situations where heating must be avoided.
Quintuple-layer epitaxy of thin films of topological insulator Bi2Se3
Authors: Zhang Guanhua , Qin Huajun , Teng Jing , Guo Jiandong , Guo Qinlin , Dai Xi , Fang Zhong , Wu Kehui
Published: August 2009

Atomically smooth, single crystalline Bi2Se3 thin films were prepared on Si(111) by molecular beam epitaxy. Scanning tunneling microscopy, low-energy electron diffraction, x-ray photoelectron emission spectroscopy, and Raman spectroscopy were used to characterize the stoichiometry and crystallinity of the film. The films grow in a self-organized quintuple layer by quintuple-layer mode, and atomically smooth films can be obtained, with controllable thickness down to one quintuple layer (∼1 nm).
Slow photoelectron velocity-map imaging spectroscopy of C3O− and C3S−
Authors: Garand Etienne , Yacovitch Tara I. , Neumark Daniel M.
Published: August 2009

High-resolution photodetachment spectra of C3O− and C3S− using slow photoelectron velocity-map imaging spectroscopy are reported. Well-resolved transitions to the neutral X̃ Σ1+ state are seen for both species. The electron affinities of C3O and C3S are determined to be EA(C3O)=1.237±0.003 eV and EA(C3S)=1.5957±0.0010 eV, respectively. Several vibrational frequencies for gas phase C3O and C3S are determined for the first time. The long progression of bending modes observed in the spectra is consistent with electronic structure calculations predicting that the C3O− and C3S− have bent equilibrium geometries.
Organic light-emitting diode with liquid emitting layer
Authors: Xu Denghui , Adachi Chihaya
Published: August 2009

We demonstrate an original organic light-emitting diode (OLED) having a neat liquid host of 9-(2-ethylhexyl)carbazole (EHCz) doped with a guest emitter of 5,6,11,12-tetraphenylnapthacene (rubrene). The device structure is composed of indium tin-oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate)/EHCz:rubrene/Cs2CO3/ITO. We demonstrate that the liquid organic semiconducting layer surely transports charge carriers, leading to electroluminescence from rubrene with the highest external quantum efficiency of ηext=0.03% at a current density of 0.26 mA/cm2. Our demonstration of the liquid-OLEDs will open another possibility of organic semiconductors and light-emitting applications.
Charge carrier concentration and temperature dependent recombination in polymer-fullerene solar cells
Authors: Foertig A. , Baumann A. , Rauh D. , Dyakonov V. , Deibel C.
Published: August 2009

We performed temperature dependent transient photovoltage and photocurrent measurements on poly(3-hexylthiophene):[6,6]-phenyl-C61 butyric acid methyl ester bulk heterojuction solar cells. We found a strongly charge carrier concentration and temperature dependent Langevin recombination prefactor. The observed recombination mechanism is discussed in terms of bimolecular recombination. The experimental results were compared with charge carrier extraction by linearly increasing voltage measurements done on the same blend system. We explain the charge carrier dynamics, following an apparent order larger than two, by dynamic trapping of charges in the tail states of the Gaussian density of states.
Resonant photoionization of defects in Si/SiO2/HfO2 film stacks observed by second-harmonic generation
Authors: Price J. , An Y. Q. , Lysaght P. S. , Bersuker G. , Downer M. C.
Published: August 2009

Internal multiphoton photoemission (IMPE) and time-dependent electrostatic field-induced second-harmonic (TD-EFISH) generation are used to probe charge trapping kinetics in Si/SiO2/Hf1−xSixO2 films. For as-deposited Si/SiO2/HfO2 samples, we observe a unique resonant TD-EFISH response to IMPE charging at incident photon energies near 1.6 eV: a delayed TD-EFISH decay not observed at off resonant energies or in x≠0 samples. We explain the TD-EFISH decay by resonant two-photon ionization of point defects and subsequent tunneling of the photoelectrons to the Si substrate. Hysteresis in the resonant TD-EFISH response shows that the photoionized defects are rechargeable and located within the HfO2 bulk.
Quinoxaline-based π-conjugated donor polymer for highly efficient organic thin-film solar cells
Authors: Kitazawa Daisuke , Watanabe Nobuhiro , Yamamoto Shuhei , Tsukamoto Jun
Published: August 2009

A quinoxaline-based π-conjugated donor polymer, poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(5′,8′-di-2-thienyl-2′,3′-diphenylquinoxaline)] (N-P7), was synthesized to achieve a high power conversion efficiency (PCE) of bulk heterojunction (BHJ)-based solar cells. The optical band-gap and highest occupied molecular orbital level of N-P7 were 1.95 and −5.37 eV, respectively. BHJ-based solar cells using N-P7 as a donor and phenyl C71 butyric acid methyl ester as an acceptor gave a PCE as high as 5.5% under AM 1.5G 100 mW/cm2 illumination. We also investigated the effects of substituent groups of quinoxaline-based polymers on the morphology of the BHJ layer.
Ultrafast dynamics of four-state magnetization reversal in (Ga,Mn)As
Authors: Zhu Yonggang , Zhang Xinhui , Li Tao , Huang Xia , Han Lifen , Zhao Jianhua
Published: August 2009

The ultrafast dynamics of in-plane four-state magnetization reversal from compressively strained (Ga,Mn)As film was investigated by magneto-optical Kerr rotation measurement. The magnetization reversal signal was dramatically suppressed upon pumping, and recovered slowly with time evolution. The low switching field Hc1 increased abruptly from 30 to 108 G on the first several picoseconds and recovered back to the value before optical pumping within about 500 ps, whereas the high switching field Hc2 did not change obviously upon pumping, implying a domain-wall nucleation/propagation at low fields and coherent magnetization rotation at high fields in the magnetization reversal process.
Characteristics of an electroless plated-gate transistor
Authors: Chen Li-Yang , Chen Huey-Ing , Huang Chien-Chang , Huang Yi-Wen , Tsai Tsung-Han , Liu Yi-Chun , Chen Tai-You , Cheng Shiou-Ying , Liu Wen-Chau
Published: August 2009

Temperature-dependent characteristics of an interesting pseudomorphic high electron mobility transistor with an electroless plated (EP) gate metal are studied and demonstrated. Under the low-temperature and low-energy electrochemical deposition conditions, the EP deposition technique provides an oxide-free metal-semiconductor interface with the reduction in surface damages. Experimentally, for a 1×100 μm2 gate-dimension EP-device, significant improvements of forward voltage, gate leakage current, Schottky barrier height, ideality factor, transconductance, drain saturation current, and IDS operating regime are found. In addition, good thermal stability of device properties are found as the temperature is increased from 300 to 500 K. Under an accelerated stress test, the studied EP-device also shows better performance over a wide temperature range. Therefore, the studied EP-gate device has a promise for high-performance electronic applications.
Correlation of crystalline defects with photoluminescence of InGaN layers
Authors: Faleev Nikolai , Jampana Balakrishnam , Jani Omkar , Yu Hongbo , Opila Robert , Ferguson Ian , Honsberg Christiana
Published: August 2009

We report structural studies of InGaN epilayers of various thicknesses by x-ray diffraction, showing a strong dependence of the type and spatial distribution of extended crystalline defects on layer thickness. The photoluminescence intensity for the samples was observed to increase with thickness up to 200 nm and decrease for higher thicknesses, a result attributed to creation of dislocation loops within the epilayer. Correlation of physical properties with crystalline perfection open the way for optimized designs of InGaN solar cells, with controlled types and dislocation densities in the InGaN epilayers, a key requirement for realizing high photocurrent generation in InGaN.
Low temperature preparation of ferroelectric bismuth titanate thin films
Authors: Xue Kan-Hao , Celinska Jolanta , Paz de Araujo Carlos A.
Published: August 2009

The low temperature metal organic decomposition techniques of ferroelectric bismuth titanate (BIT) thin films were investigated. BIT was found to be crystallized by rapid thermal processing at 450 °C. The stoichiometric Bi4Ti3O12 sample exhibited (117) orientation, while the Bi4.8Ti3O13.2 sample, with 20% excess bismuth, possessed a/b axes orientation with (117) component. Pt/Bi4.8Ti3O13.2/Pt ferroelectric capacitors were fabricated with temperature confined below 450 °C. The saturated 2Pr value was 31.1 μC/cm2. Such method is valuable for ferroelectric memories at 65 nm technology node and beyond because low temperature processes are required for the stability of interconnect material nickel silicide.
Becoming Bare Life: Asylum, Hospitality, and the Politics of Encampment
Authors: Darling Jonathan
Published: August 2009

This paper examines the politics of contemporary encampment within the UK with reference to the positioning of asylum seekers as a group subjected to a biopolitical logic of ‘compassionate repression’. The paper opens by examining the utility of presentations of the asylum seeker as an exemplar of Agamben's figure of the homo sacer. Drawing on recent critiques of the British government's apparent turn to a ‘deliberate policy of destitution’, I argue that through such acts of sovereign abandonment asylum seekers are relegated to a position reliant solely upon the ethical sensibilities of others. I then proceed to consider ways in which such a positioning ‘outside the law’ has been employed by asylum seekers and local campaigners to make ethical claims and demands upon the relational nature of the citizen as a figure of potential bare life. I then close by arguing that such an ethical gesture alone, of ‘assuming bare life’, is not enough and that the outright rejection of logics of distinction which Agamben suggests as a future politics offers little means to politically engage bare life beyond an irreconcilable ethic of the unconditionally hospitable. Opposed to this, I suggest the need to (re)engage with political theories which draw the political as always already an ethical practice in itself. Here, I examine the UK's involvement in the UNHCR Gateway Protection Programme, as an example of a conditional, and imperfect, act of hospitality, one grounded in distinction, yet one which holds both the risks of ethical practice and the possibility of political alteration at its heart.
Seoul, Conditions of Possibility, and the Postnational Hyperspace
Authors: King Ross
Published: August 2009

Korean ‘official nationalism’ (as Anderson calls it) arose late, in a context of partition and its inevitable ambiguities, Confucian self-discipline but wildly violent politics, rapid economic growth, and then Korea's pivotal role in the electronics and e-economy booms of the 1980s and 1990s. Seoul had to be constructed as the national capital in the absence of continuity in its represented past, consequent on the attempted total obliteration of Korean identity by the Japanese colonialist regime and subsequent wartime destruction. Its ‘monuments’ are virtually empty of cultural referencing; even the National Assembly is a ‘painted shed’; new cultural production is overwhelmingly either pastiche or electronic; political activity slips from the Third Estate of popular democracy to an emerging Fifth Estate of the Internet and the weblog. While print capitalism may have been a necessary enabling condition for the rise of nationalism in Europe, the Americas, and beyond, as Anderson asserts, in Korea's case we may have the paradox of the weakly defined nation slipping away, into a wider imagined community, even as the dream of Korean distinctiveness cuts ever deeper.
Lipstick, Lace, and Longing: Constructions of Femininity inside a Russian Prison
Authors: Moran Dominique , Pallot Judith , Piacentini Laura
Published: August 2009

This paper examines the construction of femininity within Russian women's prisons. On the basis of fieldwork carried out in three women's prisons in the secure and restricted penal zone within Mordovia, Russian Federation, we present unique and original qualitative data, as well as a critical engagement with contemporary Russian press sources. Starting from the assumption that the (free) female body is a particular target of Foucauldian disciplinary power, in that gender is a discipline which produces bodies and identities and operates as an effective form of social control, we examine the ways in which this disciplinary power of gender is compounded by bodily imprisonment. Criminal women are often considered not only to have broken the law but also to have offended against their culturally specific gender role expectations, and punishment applied to women prisoners is grounded not on what women are like, but on how women ‘ought’ to behave in a particular cultural context, with interventions coercing or persuading women to reintegrate into a recognisably ‘feminine’ form. We uncover Russia's exceptional and exclusionary geography of women's imprisonment, and rehabilitative and educational processes, including a beauty pageant, which seek to rescript criminal women toward a predetermined ‘ideal’ of Russian womanhood, and also explore the ways in which women seek to resist.
A new look at the role of fire-released moisture on the dynamics of atmospheric pyro-convection
Authors: Luderer Gunnar , Trentmann Jörg , Andreae Meinrat O.
Published: August 2009

We investigate the contribution of the moisture released by wildland fires to the water budget and the convection dynamics of pyro-clouds forming atop fires. Using an approach based on stoichiometric principles and parcel theory of convection, we assess the relative contribution of sensible heat and latent heat to the convection energy. We find that moisture release is of much lesser importance for the fire convection than the release of sensible heat from the combustion. We conclude from theoretical considerations that it is highly unlikely that the decrease of the cloud base of pyro-cumulus compared with that of ambient free convection is due to the fire-released moisture alone, in contrast to what has been suggested previously. In addition to the analytical results, numerical simulations of a specific case study are presented. They show that the fire-released moisture accounts only for a small portion of the total water in the pyro-cumulus cloud. Also, the effect of the fire-released moisture on the convection dynamics and the height of injection is found to be small compared with the effect of the sensible heat release from the fire.
Relationships among indices of fire severity in riparian zones
Authors: Halofsky Jessica E. , Hibbs David E.
Published: August 2009

There is no standard quantitative measure of fire severity. Although different measures of fire severity are often assumed to be closely related, information on the relationships between these measures of fire severity is limited. Information on the relationship between various fire severity indices is particularly lacking for riparian zones, critical areas of the landscape for both habitat and water quality. The present study explores relationships among several ground-based and remotely sensed indices of fire severity in riparian areas of recent fires in Oregon, including ground-based indices of overstorey fire severity (crown scorch and basal area mortality) and understorey fire severity (height of bole char and exposed mineral soil). There were relatively strong associations between the two overstorey indices of fire severity and also between the two understorey indices of fire severity. However, there were weaker associations between understorey and overstorey fire severity indices, suggesting they are at least partially independent. Results also suggested weak associations between ground-based fire severity indices and remotely sensed fire severity assessments in riparian areas. Overall, we show there are limitations to the interpretation and use of these commonly used fire severity assessments in riparian areas.
Validation studies of EUMETSAT's active fire monitoring product over Turkey
Authors: Tekeli Ahmet Emre , Sönmez İbrahim , Erdi Erdem , Demir Fatih
Published: August 2009

Fire detection and monitoring are challenging tasks that require continuous, early and quick responses that are as accurate as possible. Satellite-based systems are indispensable tools for operational and research agencies to accomplish such a demanding task. The frequent and continuous imagery capability of the geostationary satellites makes them the best candidate for early fire detection systems. The main purpose of the present paper is to analyze the spatio-temporal distribution of active fire monitoring (FIR) products of the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT)’s Meteosat Second Generation (MSG) satellite with in situ data for the summer of 2006 over Turkey. In situ data were obtained from the fire reports of the Ministry of Environment and Forestry, Turkey. The main shortcomings of the MSG active fire monitoring product validation arise from the pixel resolution and fire coverage, which are examined on the basis of some recent examples. The diurnal cycle of active fires identified well with the product. The burnt area effects on the accuracy of hit ratios were also analyzed. It is seen that the possibility for the fire to be detected by MSG increases with increasing burnt area. Even with the present anomalies, remote sensing may provide a consistent systematic way of monitoring fires, removing human biases and enabling a long-term dataset, which has been a goal of Global Observation of Forest and Land Cover Dynamics (GOFC/GOLD).
Effect of vegetation heterogeneity on radiative transfer in forest fires
Authors: Pimont François , Dupuy Jean-Luc , Caraglio Yves , Morvan Dominique
Published: August 2009

Wildland fires are driven by the heat transferred from the fire source to the unburned fuel bed and this transfer is likely to be affected by the spatial heterogeneity of fuel element distributions at different scales from shoot to stand. In a context of theoretical fire modelling, we investigated the impact of a departure from randomness of fuel distributions on the radiative transfer of energy. Our methodology was derived from the approach developed for solar radiation in heterogeneous canopies or clouds and was modified to suit an analysis of fire behaviour. Some fine and coarse fuel distributions for several Mediterranean fuel types were derived from field measurements and plant architecture modelling. A comparison of the average irradiances in different fuels showed whether heterogeneity effects were significant or not. Results showed that both marked spatial variability in fuel distribution (low cover fraction and large clumps) and a high vegetation density were required to provide significant effects. The radiative transfer in heterogeneous maritime pines and in dense shrub stands was significantly affected by heterogeneity, mainly at crown and shoot scales. Less pronounced effects were observed in Aleppo pine stand and light shrubs. In terms of fuel modelling, the 2-m resolution used in a fire model such as FIRETEC seems to be sufficient for the fuel types investigated here, with the exception of dense small clumps in shrublands. An effective coefficient was proposed for these latter cases.
The effects of fire on avian communities: spatio-temporal attributes of the literature 1912 - 2003
Authors: Leidolf Andreas , Bissonette John A.
Published: August 2009

We reviewed the temporal, geographic, and biogeographic distribution, as well as relevant research and publication attributes, of 512 documents addressing the effects of fire on avian communities, to provide an assessment of the scope of this literature and recommendations for future research. We summarized relevant attributes of all documents to identify patterns that were then tested against appropriate null models. Most documents reported on original research, with the literature evenly divided between studies investigating controlled fire and those reporting on uncontrolled wildfires. Conceptual reviews made up the second largest category; methodological reviews, bibliographies, and meta-analyses were rare. Although the literature examined spans nearly a century, most documents were published within the last 15 years, with new literature being added at an increasing rate. However, increases seem to be skewed towards original research at the expense of synthesis. An overwhelming majority of documents were published in peer-reviewed scientific journals and in English. Other important publication outlets included MS and PhD theses and conference proceedings. The spatial distribution of documents by continent and biogeographic domain and division differed significantly from expectations based on land area. Future research on avian community response to fire should focus on (1) continued synthesis, emphasizing methodological reviews, bibliographies, and North America; (2) increasing research efforts in areas currently underrepresented in the literature, including Africa, Asia, and South and Central America; and (3) meta-analyses.
Landscape structural features control fire size in a Mediterranean forested area of central Spain
Authors: Viedma Olga , Angeler D. G. , Moreno José M.
Published: August 2009

Landscape structure may affect fire propagation and fire size. Propagation may be favoured in landscapes that are homogeneous and hindered at places of greater heterogeneity, and where discontinuities occur. We tested whether there is continuity in landscape structure across the edges of 110 fires in the Sierra de Gredos (central Spain). We used Landsat Multispectral Scanner images to map and assess the land-cover composition and other features of fires. Landscape diversity along the pixel row of the fire edge and of the two adjacent ones (burned and unburned) was compared for all fires. Additionally, changes in landscape properties and fuel hazard perpendicular to the fire edge evaluated the degree of discontinuity from inside the burn towards the outside across the edge. Fire size was related to landscape properties and weather conditions using generalized linear regression models. Diversity increased from inside the burn towards the edge and outside the burn. Discontinuity in land-cover types and fuel hazard increased from the inside towards the outside. Modelling confirmed that fire size was in part related to landscape characteristics of the burned area and of the edges of the fire perimeter. We conclude that landscape structure was important in determining fire size in this area.
Forecasting distributions of large federal-lands fires utilizing satellite and gridded weather information
Authors: Preisler Haiganoush K. , Burgan Robert E. , Eidenshink Jeffery C. , Klaver Jacqueline M. , Klaver Robert W.
Published: August 2009

The current study presents a statistical model for assessing the skill of fire danger indices and for forecasting the distribution of the expected numbers of large fires over a given region and for the upcoming week. The procedure permits development of daily maps that forecast, for the forthcoming week and within federal lands, percentiles of the distributions of (i) number of ignitions; (ii) number of fires above a given size; (iii) conditional probabilities of fires greater than a specified size, given ignition. As an illustration, we used the methods to study the skill of the Fire Potential Index – an index that incorporates satellite and surface observations to map fire potential at a national scale – in forecasting distributions of large fires.
Implications of changing climate for global wildland fire
Authors: Flannigan Mike D. , Krawchuk Meg A. , de Groot William J. , Wotton B. Mike , Gowman Lynn M.
Published: August 2009

Wildland fire is a global phenomenon, and a result of interactions between climate–weather, fuels and people. Our climate is changing rapidly primarily through the release of greenhouse gases that may have profound and possibly unexpected impacts on global fire activity. The present paper reviews the current understanding of what the future may bring with respect to wildland fire and discusses future options for research and management. To date, research suggests a general increase in area burned and fire occurrence but there is a lot of spatial variability, with some areas of no change or even decreases in area burned and occurrence. Fire seasons are lengthening for temperate and boreal regions and this trend should continue in a warmer world. Future trends of fire severity and intensity are difficult to determine owing to the complex and non-linear interactions between weather, vegetation and people. Improved fire data are required along with continued global studies that dynamically include weather, vegetation, people, and other disturbances. Lastly, we need more research on the role of policy, practices and human behaviour because most of the global fire activity is directly attributable to people.
Multiparametric analysis of focal adhesion formation by RNAi-mediated gene knockdown
Authors: Winograd-Katz Sabina E. , Itzkovitz Shalev , Kam Zvi , Geiger Benjamin
Published: August 2009

Cell adhesion to the extracellular matrix is mediated by elaborate networks of multiprotein complexes consisting of adhesion receptors, cytoskeletal components, signaling molecules, and diverse adaptor proteins. To explore how specific molecular pathways function in the assembly of focal adhesions (FAs), we performed a high-throughput, high-resolution, microscopy-based screen. We used small interfering RNAs (siRNAs) to target human kinases, phosphatases, and migration- and adhesion-related genes. Multiparametric image analysis of control and of siRNA-treated cells revealed major correlations between distinct morphological FA features. Clustering analysis identified different gene families whose perturbation induced similar effects, some of which uncoupled the interfeature correlations. Based on these findings, we propose a model for the molecular hierarchy of FA formation, and tested its validity by dynamic analysis of FA formation and turnover. This study provides a comprehensive information resource on the molecular regulation of multiple cell adhesion features, and sheds light on signaling mechanisms regulating the formation of integrin adhesions.
The H2BK123Rgument
Authors: Latham John A. , Dent Sharon Y.R.
Published: August 2009

The discovery of trans-regulation of histone H3K4 methylation by ubiquitination of histone H2BK123 generated much excitement in the field of chromatin biology. Recently, the veracity of this example of cross talk between histone modifications in yeast was challenged (Foster and Downs, 2009. J. Cell Biol. doi:10.1083/jcb.200812088) but ultimately reconfirmed in a study in this issue (Nakanishi et al., 2009. J. Cell Biol. doi:10.1083/jcb.200906005).
The value of information in fisheries management: North Sea herring as an example
Authors: Mäntyniemi Samu , Kuikka Sakari , Rahikainen Mika , Kell Laurence T. , Kaitala Veijo
Published: August 2009

Mäntyniemi, S., Kuikka, S., Rahikainen, M., Kell, L. T., and Kaitala, V. 2009. The value of information in fisheries management: North Sea herring as an example. – ICES Journal of Marine Science, 66: 2278–2283. We take a decision theoretical approach to fisheries management, using a Bayesian approach to integrate the uncertainty about stock dynamics and current stock status, and express management objectives in the form of a utility function. The value of new information, potentially resulting in new control measures, is high if the information is expected to help in differentiating between the expected consequences of alternative management actions. Conversely, the value of new information is low if there is already great certainty about the state and dynamics of the stock and/or if there is only a small difference between the utility attached to different potential outcomes of the alternative management action. The approach can, therefore, help when deciding on the allocation of resources between obtaining new information and improving management actions. In our example, we evaluate the value of obtaining hypothetically perfect knowledge of the type of stock–recruitment function of the North Sea herring (Clupea harengus) population.
Functional genome screen for therapeutic targets of osteosarcoma
Authors: Yamaguchi Umio , Honda Kazufumi , Satow Reiko , Kobayashi Eisuke , Nakayama Robert , Ichikawa Hitoshi , Shoji Ayako , Shitashige Miki , Masuda Mari , Kawai Akira , Chuman Hirokazu , Iwamoto Yukihide , Hirohashi Setsuo , Yamada Tesshi
Published: August 2009

Osteosarcoma (OS) is the most frequent primary malignant bone tumor of children and young adults. Although the introduction of combined neoadjuvant chemotherapy has markedly improved survival, the outcome of OS patients with distant metastasis and/or poor response to chemotherapy is still unsatisfactory. Therefore there is a need to develop new therapeutic agents that suppress OS cell proliferation with higher efficacy. The protein kinases are a family of genes that play critical roles in various signaling pathways. Some cancer cells show addiction to constitutive activation of certain signaling pathways for proliferation and survival. To identify new drug targets for OS, we screened a panel of small interfering RNAs (siRNAs) that target 691 genes encoding human protein kinases and related proteins. We found that different constructs of siRNA specifically targeting polo‐like 1 kinase (PLK1) significantly caused mitotic cell cycle arrest and subsequent apoptotic cell death in a variety of OS cell lines. siRNA targeting PLK1 also suppressed the growth of OS xenografts established in immunodeficient mice. Recently, phase I clinical trials of PLK1 chemical inhibitors have been reported. Our results indicate that PLK1 is a promising molecular target for pharmacologic intervention in OS. (Cancer Sci 2009; 100: 2268–2274)
Effect of drying temperatures on chemical and morphological properties of acorn flours
Authors: Correia Paula R. , Leitão António E. , Beirão‐da‐Costa Maria L.
Published: August 2009

Drying curves at different temperatures were established for Quercus suber and Quercus rotundifolia fruits. Flours produced by milling fruits dried at different conditions were evaluated for colour, starch granules morphology, amylose and sugars content. The drying temperature was positively related to the reducing sugar content and negatively to starch content. The amilose content generally increased with drying temperature and the effect was more evident for the Q. rotundifolia. Results showed that flour colour parameters generally decreased with increased drying temperature. However, the drying temperature does not seem to affect starch morphology. It can also be stated that Q. suber produced darker flours, higher amylose and reducing sugar content, and bigger starch granules. Q. rotundifolia showed a lower level of damaged starch and higher fat and disaccharides content. According to the results, it was possible to conclude that drying temperature exerted marked effects on the properties of acorn flours in both studied species.
Influence of sodium and calcium ions on rheological behaviour of wheat glutenins extracted in alkaline ethanol solution
Authors: Song Yihu , Zheng Qiang
Published: August 2009

Wheat glutenins were extracted in alkaline aqueous solution containing 50% (v/v) ethanol and 0.025 m NaOH from the gluten residue after extraction using 70% (v/v) aqueous ethanol. Rheological behaviours of the solutions were investigated as a function of protein concentration and ion strength. Sodium (Na+) and calcium (Ca2+) ions have different influences on the rheological behaviour of the glutenin solution of 48 mg mL−1. While addition of Na+ results in Newtonian fluids with a reduction in apparent viscosity in comparison with the salt‐free solution, addition of Ca2+ leads to the formation of a viscoelastic network with enhanced shear‐thinning. The solutions containing 0.2 m and 0.4 m Ca2+ exhibit yielding at low strain rates. The solution containing 0.6 m Ca2+ behaves as a pseudoplastic fluid with the appearance of two Newtonian plateaus at low and high strain‐rate limits.
Extraction of volatile and semi‐volatile components from oak wood used for aging wine by miniaturised pressurised liquid technique
Authors: Alañón Maria Elena , Ramos Lourdes , Díaz‐Maroto Maria Consuelo , Pérez‐Coello Maria Soledad , Sanz Jesús
Published: August 2009

A miniaturised pressurised liquid technique has been applied to the extraction of volatile compounds present in oak wood samples used in making wine. The solvent extraction performed at high pressure and temperature has allowed the detection of a large number of compounds some of which present sensory and antioxidant properties. The effect of the main process variables on the efficiency of extraction has been studied: the composition of the extracted fraction depended mainly on the polarity of the solvent and the extraction temperature had a high influence on the extracted amount, while the effect of static extraction time and pressure were almost negligible. The highest recoveries were obtained for dichloromethane, for two static 10‐min extraction cycles at 60 °C. Among the solvent extraction techniques, miniaturised pressurised liquid extraction presents several advantages, such as the use of reduced amounts of both sample and solvent and high extraction efficiency.
A pilot study into the chemical and sensorial effect of thyme and pennyroyal essential oil on hens eggs
Authors: Smith Tegan J. , George David R. , Sparagano Olivier A. E. , Seal Chris , Shiel Robert S. , Guy Jonathan H.
Published: August 2009

Previously, it has been shown that thyme and pennyroyal essential oils have potential as acaricides against the poultry red mite Dermanyssus gallinae. The effect of these oils on the occurrence of taint in hens’ eggs was investigated using in vitro immersion tests and in vivo methods where poultry huts containing laying hens were sprayed weekly with oil. Analysis of extracts from eggs by gas chromatography mass spectrometry (GCMS) showed that no detectable taint was present in hens’ eggs. However, consumer sniff tests, although restricted and only preliminary in nature, showed a significant negative response to the smell of both unbroken and cracked open eggs between those taken from poultry huts treated with pennyroyal essential oil and all other eggs tested. Some essential oils, such as thyme, may be more suitable as an acaracidal product than others, such as pennyroyal, for the use within a commercial poultry system for laying hens.
Reduction of Aspergillus parasiticus on hazelnut surface by UV‐C treatment
Authors: Basaran Pervin
Published: August 2009

The reduction in counts of Aspergillus spp. and aflatoxin production was assessed on hazelnuts after 254 nm UV‐C treatment. A 2 log reduction in Aspergillus spp. counts was observed after 2 h reperated UV‐C treatment on hazelnuts. Only one dose treatment of 6 h UV‐C was sufficient to yield nearly 25% reduction in aflatoxin B1 and G1, but this dose had no effect on aflatoxin B2 and G2. SDS‐PAGE of the crude extracellular protein isolated at different growth periods of A. parasiticus in liquid medium revealed production of twelve extracellular proteins starting from day 4 of inoculation, and all twelve proteins decreased after UV‐C radiation. No molecular changes in macromolecular components of hazelnut with UV‐C treatment were detected by Fourier Transform Infrared spectroscopy.
Phylogeography of Southern Water Vole (Arvicola sapidus): evidence for refugia within the Iberian glacial refugium?
Authors: CENTENO‐CUADROS A. , DELIBES M. , GODOY J. A.
Published: August 2009

The role of Southern European peninsulas as glacial refugia for temperate species has been widely established, but phylogeographic patterns within refugia are being only recently addressed. Here we describe the phylogeographic patterns for Southern water vole (Arvicola sapidus) in its whole distribution across Iberia and France. Control region and cytochrome b sequences were obtained for 228 samples from 130 localities across Iberia and France. Eighty‐five haplotypes were found in total yielding a high overall mitochondrial diversity (π = 0.027; H = 0.974). Phylogeographic structure was relatively shallow (3.1% average intraspecific divergence) with few supported clades and 95% and 90% maximum parsimony unconnected networks, but significant, as reflected in increased pairwise nucleotide divergences with distance (r = 0.197, P = 0.03) and significant autocorrelation up to ∼500 km. Spatial analysis of molecular variance analysis detected seven geographical groups explaining 43.73% of the total mitochondrial variation. We detected demographic expansions in three of these groups. A recent colonization of France from Iberia was suggested and estimated around 62 000 years bp by an isolation‐with‐migration model. Our results suggest the contribution of episodes of isolation in glacial subrefugia in Iberia, but seem to exclude a long‐term isolation over successive glacial cycles. Phylogeographic divergence was probably tempered by relatively large population sizes and rapid and extensive mixing among subrefugia during interglacials, that might have eroded the phylogeographic structure accumulated at glacial peaks. Phenotypic differences in A. sapidus do not delineate historically isolated intraspecific divisions and do not warrant subspecific delimitations. Our results do support the existence of subrefugia within Iberia and their role in promoting intraspecific divergences.