bluuebunny/crossref_metadata_2025 huggingface dataset:
A new compact instrument for Raman, laser-induced breakdown, and laser-induced fluorescence spectroscopy of works of art and their constituent materials
Authors: Osticioli I. , Mendes N. F. C. , Nevin A. , Zoppi A. , Lofrumento C. , Becucci M. , Castellucci E. M.
Published: July 2009

A small, potentially transportable prototype instrument capable of carrying out Raman, laser-induced breakdown (LIB), and laser-induced fluorescence (LIF) spectroscopy using a single pulsed laser source was developed for the analysis of cultural heritage objects. The purpose of this instrumentation is to perform fast and reliable analysis of surfaces with minimum damage to an object. For this purpose, a compact (51×203×76 mm) nanosecond Q-switched neodymium doped yttrium aluminum garnet laser (8 ns, 20 Hz, 0.01–115 mJ/pulse) was used as an irradiation source. The use of a nanosecond-gated detector sensitive between 180 and 900 nm allows the acquisition of elemental emissions in LIB spectroscopy and can also be employed for both LIF and time-resolved Raman spectroscopy. In this work, attention is focused on the description of the instrument and its optical components, and two examples of applications for the analysis of pigments and binding media used in works of art are presented.
Electron trajectories and betatron oscillation in the wake bubble in laser-plasma interaction
Authors: Wu Hai-Cheng , Xie Bai-Song , Liu Ming-Ping , Hong Xue-Ren , Zhang Shan , Yu M. Y.
Published: July 2009

The trajectories of electrons originating from different initial locations in the unperturbed plasma during the interaction of an ultraintense laser with underdense plasma in the bubble regime are followed by particle-in-cell simulation. It is found that plasma electrons initially aligned with the rim of the laser focal spot contribute most to the bow wave in front of the bubble and those aligned with the lateral bubble sheath edge contribute most to the self-injection at the back of the bubble. A scaling law between the transverse electric and magnetic fields for the case where there are many electrons in the bubble is given and discussed in terms of betatron oscillations of the injected electrons.
Tunable terahertz band planar Bragg reflectors
Authors: Ginzburg N. S. , Malkin A. M. , Peskov N. Yu. , Sergeev A. S. , Zaslavsky V. Yu. , Kamada K. , Soga Y.
Published: July 2009

A tunable planar narrow-band Bragg reflector based on coupling of the two propagating modes and a cutoff mode is considered. Coupled-wave analysis together with direct numerical simulations demonstrate operation of the proposed scheme up to the terahertz frequency band. Compatibility with the transportation of an intense electron beam encourages the use of a novel Bragg reflector in powerful long-pulse free electron lasers.
Vibrational energy transport in the presence of intrasite vibrational energy redistribution
Authors: Schade Marco , Hamm Peter
Published: July 2009

The mechanism of vibrational energy flow is studied in a regime where a diffusion equation is likely to break down, i.e., on length scales of a few chemical bonds and time scales of a few picoseconds. This situation occurs, for example, during photochemical reactions in protein environment. To that end, a toy model is introduced that on the one hand mimics the vibrational normal mode distribution of proteins, and on the other hand is small enough to numerically time propagate the system fully quantum mechanically. Comparing classical and quantum-mechanical results, the question is addressed to what extent the classical nature of the molecular dynamics simulations (which would be the only choice for the modeling of a real molecular system) affects the vibrational energy flow mechanism. Small differences are found which are due to the different ways classical and quantum mechanics distribute thermal energy over vibrational modes. In either case, a ballistic and a diffusive phase can be identified. For these small length and time scales, the latter is governed by intrasite vibrational energy redistribution, since vibrational energy does not necessarily thermalize completely within individual peptide units. Overall, the model suggests a picture that unifies many of the observations made recently in experiments.
Local softness, softness dipole, and polarizabilities of functional groups: Application to the side chains of the 20 amino acids
Authors: Krishtal Alisa , Senet Patrick , Van Alsenoy Christian
Published: July 2009

The values of molecular polarizabilities and softnesses of the 20 amino acids were computed ab initio (MP2). By using the iterative Hirshfeld scheme to partition the molecular electronic properties, we demonstrate that the values of the softness of the side chain of the 20 amino acids are clustered in groups reflecting their biochemical classification, namely: aliphatic, basic, acidic, sulfur containing, and aromatic amino acids. The present findings are in agreement with previous results using different approximations and partitioning schemes [P. Senet and F. Aparicio, J. Chem. Phys. 126, 145105 (2007)]. In addition, we show that the polarizability of the side chain of an amino acid depends mainly on its number of electrons (reflecting its size) and consequently cannot be used to cluster the amino acids in different biochemical groups, in contrast to the local softness. Our results also demonstrate that the global softness is not simply proportional to the global polarizability in disagreement with the intuition that “a softer moiety is also more polarizable.” Amino acids with the same softness may have a polarizability differing by a factor as large as 1.7. This discrepancy can be understood from first principles as we show that the molecular polarizability depends on a “softness dipole vector” and not simply on the global softness.
Improved photovoltaic performance of bilayer heterojunction photovoltaic cells by triplet materials and tetrapod-shaped colloidal nanocrystals doping
Authors: Li Yanqin , Mastria Rosanna , Li Kechang , Fiore Angela , Wang Yue , Cingolani Roberto , Manna Liberato , Gigli Giuseppe
Published: July 2009

The aim of this work is to investigate the photovoltaic properties of indium tin oxide/poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) / poly(3-hexylthiophene-2,5-diyl) /fullerene/aluminum bilayer heterojunction solar cells when the active polymer layer is doped with triplet organic molecules (a platinum porphyrin complex) and tetrapod-shaped colloidal CdTe nanocrystals. In both cases, the device photovoltaic responses are greatly improved due to the enhanced triplet exciton population, in the case of molecular doping, and due to the improved charge transport and charge separation characteristics, for nanocrystal doping. The latter are related both to the relatively large nanostructured interface and to the high intrinsic carrier mobilities of nanocrystals.
Oxygen passivation of vacancy defects in metal-nitride gated HfO2/SiO2/Si devices
Authors: Cartier E. , Hopstaken M. , Copel M.
Published: July 2009

We show that oxygen can be diffused through thin TiN layers to correct flatband voltage offsets in HfO2/SiO2/Si structures, achieving nearly band-edge capacitance voltage characteristics without undue growth of parasitic SiO2. Photoemission reveals that the TiN remains conductive despite mild oxidation, although over-oxidation results in insulating layers. Secondary ionization mass spectroscopy of samples treated with isotopically labeled O18 was used to assess how much oxygen is required to fully passivate the defects caused by thermal processing of metallized HfO2/SiO2/Si devices.
Electro-optical light scattering shutter using electrospun cellulose-based nano- and microfibers
Authors: Almeida P. L. , Kundu S. , Borges J. P. , Godinho M. H. , Figueirinhas J. L.
Published: July 2009

Electrospun cellulose-based nano and microfibers and a nematic liquid crystal are used to assemble an electro-optical (EO) light-scattering device that shows enhanced characteristics when compared to similar devices. Based on the controlled scattering of light in the composite system, the device can achieve light transmission coefficients tunable from 1% up to around 89%. Simulation of the EO behavior indicates that the roughness of the polymer-liquid crystal interface is crucial for the optical performance of the device.
Fragmentation of peptide negative molecular ions induced by resonance electron capture
Authors: Vasil’ev Yury V. , Figard Benjamin J. , Morré Jeff , Deinzer Max L.
Published: July 2009

A simple robust method to study resonance gas-phase reactions between neutral peptides of low volatility and free electrons has been designed and implemented. Resonance electron capture (REC) experiments were performed by several neutral model peptides and two naturally occurring peptides. The assignment of negative ions (NIs) formed in these gas-phase reactions was based on high mass-resolving power experiments. From these accurate mass measurements, it was concluded that fragment NIs formed by low (1–2 eV) energy REC are of the same types as those observed in electron capture/transfer dissociation, where the positive charge is a factor. The main feature resulting from these REC experiments by peptides is the occurrence of zn−1 ions, which are invariably of the highest abundances in the negative ion mass spectra of larger peptides. [M–H]− NIs presumably the carboxylate anion structure dominate the REC spectra of smaller peptides. There was no evidence for the occurrence of the complementary reaction, i.e., the formations of cn+1 ions. Instead, cn ions arose without hydrogen/proton transfer albeit with lower abundances than that observed for zn−1 ions. Only the amide forms of small peptides showed more abundant ion peaks for the cn ions than for the zn−1 ions. The mechanisms for the N–Cα bond cleavage are discussed.
Geometrical and electronic structures of small Wn (n=2–16) clusters
Authors: Du Jiguang , Sun Xiyuan , Meng Daqiao , Zhang Pengcheng , Jiang Gang
Published: July 2009

The geometrical and electronic structures of Wn (n=2–16) clusters are investigated within the framework of a gradient-corrected density functional theory. The close-packed configurations are preferred for small tungsten clusters up to n=16. The most energetic favorable structures of W14, W15, and W16 clusters, exhibiting similar electronic band structures, are all formed based on body centered cubic (bcc) unit. The clusters with size of n=8, 12, and 15 are found to be more stable with respect to their respective neighbors. The analyses of atomic orbit projected density of states and highest occupied molecular orbital, lowest unoccupied molecular orbital isosurfaces indicate that 5d electrons play a dominant role in the chemical activities of tungsten clusters. The clearly s-d hybridizations are primary presented in bonding W atoms of smaller clusters, as the cluster sizes increase, the 6p orbitals are gradually involved in chemical bonding. Our calculated vertical ionization potentials (VIPs) indicate that the W8 and W12 clusters correspond to the high VIPs. The vertical electron affinities are slightly underestimated in our investigation, but follow the trends of experimental data in principle.
Heterogeneous conductorlike solvation model
Authors: Si Dejun , Li Hui
Published: July 2009

A heterogeneous conductorlike solvation model (conductorlike screening model/conductorlike polarizable continuum model) that uses different local effective dielectrics for different portions of the solute cavity surface is implemented for quantum chemical Hartree–Fock and Kohn–Sham methods. A variational treatment is used to form the heterogeneous solvation operator, so a simple analytic expression of the energy gradients, which are vital for geometry optimization and molecular dynamics simulation, is derived and implemented. Using the new Fixed Points with Variable Areas surface tessellation scheme, continuous and smooth potential energy surfaces as well as analytic gradients are obtained for this heterogeneous model. Application of the heterogeneous solvation model to a realistic quantum model consisting of 101 atoms for the type-1 Cu center in rusticyanin shows that the desolvation due to protein burial can likely raise the reduction potential by ∼200 mV and, including the heterogeneity in geometry optimization, can likely affect the results by ∼2 kcal/mol or ∼70 mV.
Phase-transition driven memristive system
Authors: Driscoll T. , Kim H.-T. , Chae B.-G. , Di Ventra M. , Basov D. N.
Published: July 2009

Memristors are passive circuit elements which behave as resistors with memory. The recent experimental realization of a memristor has triggered interest in this concept and its possible applications. Here, we demonstrate memristive response in a thin film of vanadium dioxide. This behavior is driven by the insulator-to-metal phase transition typical of this oxide. We discuss details of this form of phase-change memristance and potential applications of our device. Most importantly, our results demonstrate the potential for a realization of memristive systems based on phase-transition phenomena.
Role of edge dislocation and Si impurity in linking the blue luminescence and yellow luminescence in n-type GaN films
Authors: Zhao D. G. , Jiang D. S. , Zhu J. J. , Liu Z. S. , Wang H. , Zhang S. M. , Wang Y. T. , Yang Hui
Published: July 2009

A close relationship is found between the blue and yellow luminescence bands in n-type GaN films, which are grown without intentional acceptor doping. The intensity ratio of blue luminescence to yellow luminescence (IBL/IYL) decreases with the increase in edge dislocation densities as demonstrated by the (102) full width at half maximum of x-ray diffraction. In addition, the IBL/IYL ratio decreases with the increase in Si doping. It is suggested that the edge dislocation and Si impurity play important roles in linking the blue and yellow luminescence.
Multiplexed highly sensitive detections of cancer biomarkers in thermal space using encapsulated phase change nanoparticles
Authors: Ma Liyuan , Hong Yan , Ma Zeyu , Kaittanis Charalambos , Perez J. Manuel , Su Ming
Published: July 2009

We describe a multiplexed highly sensitive method to detect cancer biomarkers using silica encapsulated phase change nanoparticles as thermal barcodes. During phase changes, nanoparticles absorb heat energy without much temperature rise and show sharp melting peaks (0.6 °C). A series of phase change nanoparticles of metals or alloys can be synthesized in such a way that they melt between 100 and 700 °C, thus the multiplicity could reach 1000. The method has high sensitivity (8 nM) that can be enhanced using materials with large latent heat, nanoparticles with large diameter, or reducing the grafting density of biomolecules on nanoparticles.
Ammonia: A source of hydrogen dopant for InN layers grown by metal organic vapor phase epitaxy
Authors: Ruffenach S. , Moret M. , Briot O. , Gil B.
Published: July 2009

Thermal annealing of InN layers grown by metal organic vapor phase epitaxy (MOVPE) is investigated in nitrogen atmosphere for temperatures ranging from 400 to 550 °C and for heat treatment times up to 12 h. This treatment results in hydrogen outdiffusion, lowering significantly the residual n-type background doping. This mechanism is shown to be reversible through thermal annealing under ammonia atmosphere, responsible of hydrogen incorporation during growth. These results establish a MOVPE process allowing the obtention of InN samples, which exhibit similar electrical properties than molecular beam epitaxy grown samples: a key issue in view of future industrial production of InN based devices.
Midinfrared intersubband absorption in InGaAs/GaAsSb multiple quantum wells
Authors: Nobile M. , Detz H. , Mujagić E. , Andrews A. M. , Klang P. , Schrenk W. , Strasser G.
Published: July 2009

We report on the observation of midinfrared intersubband (ISB) absorption in InGaAs/GaAsSb multiple quantum wells grown lattice-matched to InP substrates by molecular beam epitaxy. ISB absorption in a broad wavelength region (5.8–11.6 μm) is observed in quantum wells with well widths ranging between 4.5 and 12 nm. The conduction band offset at the InGaAs/GaAsSb heterointerface is measured to be 360 meV, giving an excellent agreement between the theoretically calculated ISB transition energies and the Fourier-transform infrared spectroscopy measurements over the whole range of well widths under investigation.
Observation of enhancement and suppression in four-wave mixing processes
Authors: Li Changbiao , Zheng Huaibin , Zhang Yanpeng , Nie Zhiqiang , Song Jianping , Xiao Min
Published: July 2009

We report our observations of enhancement and suppression between two competing four-wave mixing (FWM) processes. The results show the evolution of the dressed effects (from pure enhancement into pure suppression) in the degenerate FWM processes. Moreover, due to induced atomic coherence in the system, there exist different interplays between these two FWM processes via different detuning parameters. In addition, the power dependences of enhancement and suppression are studied. Theoretical calculations are carried out, which are in good agreement with the experimental observations.
Single ricin detection by atomic force microscopy chemomechanical mapping
Authors: Chen Guojun , Zhou Jianfeng , Park Bosoon , Xu Bingqian
Published: July 2009

The authors report on a study of detecting ricin molecules immobilized on chemically modified Au (111) surface by chemomechanically mapping the molecular interactions with a chemically modified atomic force microscopy (AFM) tip. AFM images resolved the different fold-up conformations of single ricin molecule as well as their intramolecule structure of A- and B-chains. AFM force spectroscopy study of the interaction indicates that the unbinding force has a linear relation with the logarithmic force loading rate, which agrees well with calculations using one-barrier bond dissociation model.
Digital optical spectrometer-on-chip
Authors: Babin S. , Bugrov A. , Cabrini S. , Dhuey S. , Goltsov A. , Ivonin I. , Kley E.-B. , Peroz C. , Schmidt H. , Yankov V.
Published: July 2009

A concept of digital optical spectrometer-on-chip is proposed and results of their fabrication and characterization are reported. The devices are based on computer-designed digital planar holograms which involves millions of lines specifically located and oriented in order to direct output light into designed focal points according to the wavelength. Spectrometers were fabricated on silicon dioxide and hafnium dioxide planar waveguides using electron beam lithography and dry etching. Optical performances of devices with up to 1000 channels for a central wavelength of 660 nm are reported.
Frozen Gaussian series representation of the imaginary time propagator theory and numerical tests
Authors: Zhang Dong H. , Shao Jiushu , Pollak Eli
Published: July 2009

Thawed Gaussian wavepackets have been used in recent years to compute approximations to the thermal density matrix. From a numerical point of view, it is cheaper to employ frozen Gaussian wavepackets. In this paper, we provide the formalism for the computation of thermal densities using frozen Gaussian wavepackets. We show that the exact density may be given in terms of a series, in which the zeroth order term is the frozen Gaussian. A numerical test of the methodology is presented for deep tunneling in the quartic double well potential. In all cases, the series is observed to converge. The convergence of the diagonal density matrix element is much faster than that of the antidiagonal one, suggesting that the methodology should be especially useful for the computation of partition functions. As a by product of this study, we find that the density matrix in configuration space can have more than two saddle points at low temperatures. This has implications for the use of the quantum instanton theory.
Effect of flow damping on drift-tearing magnetic islands in tokamak plasmas
Authors: Fitzpatrick R. , Waelbroeck F. L.
Published: July 2009

A systematic fluid theory of nonlinear drift-tearing magnetic island dynamics in a conventional large aspect-ratio low-β circular cross-section tokamak plasma is derived from a set of single-helicity reduced neoclassical-magnetohydrodynamical equations which incorporate electron and ion diamagnetic flows, ion gyroviscosity, poloidal and toroidal flow damping, cross flux-surface momentum and particle transport, the sound wave, and the drift wave. The equations neglect the compressible Alfvén wave, electron inertia, the electron viscosity tensor, magnetic field-line curvature, and finite ion orbit widths. A collisional closure is used for plasma dynamics parallel to the magnetic field. The influence of various different levels of flow damping on the phase velocity of an isolated island, as well as the ion polarization term appearing in its Rutherford equation, are investigated in detail. Furthermore, it is found that, under certain circumstances, a locked island is subject to destabilizing ion polarization term to which a comparable isolated (i.e., rotating) island is not.
Supplements containing Acacia karroo foliage reduce nematode burdens in Nguni and crossbred cattle
Authors: Xhomfulana V. , Mapiye C. , Chimonyo M. , Marufu M. C.
Published: July 2009

The objective of this study was to compare nematode worm burdens in Nguni and crossbred cattle supplemented with Acacia karroo leaf meal. Eighteen Nguni (274.4 ± 17.34 kg) and 12 crossbred (230.5 ± 14.62 kg) steers aged 19 months were allocated to three dietary treatments: A. karroo leaf meal, sunflower cake and control with no supplement. Steers in all the treatments grazed on natural pasture whereas those on A. karroo leaf meal and sunflower cake diets were given an additional 1.5 kg and 650 g of feed, respectively, to supply 150 g of protein per day for 60 days. Faecal samples collected from the steers’ recta every fortnight were examined for nematode egg types using the modified McMaster technique. At slaughter, the abomasa and intestines were collected, opened and washed for worm identification. Nguni steers supplemented with the A. karroo leaf meal diet had the lowest mean strongyles egg counts and mean total egg counts (P < 0.05). Steers that received the A. karroo leaf meal and sunflower cake diets had lower Haemonchus contortus and Oesophagostomum colombianum worm burdens than those that received the control diet (P < 0.05). Mean strongyles and Strongyloides egg counts, and H. contortus and Oes. colombianum worm counts were negatively correlated with average daily gain and body condition scores (P < 0.05). Generally, Nguni cattle supplemented with A. karroo leaf meal had the lowest egg loads and worm burdens. It was concluded that supplementing cattle with A. karroo could reduce nematode burdens.
Pasture systems to improve productivity of sheep in south-western Victoria. 1. Growth, composition, nutritive value and persistence of resown pastures
Authors: Saul Geoffrey , Kearney Gavin , Borg Dion
Published: July 2009

Two pasture systems were compared at five on-farm sites across south-western Victoria between 1990 and 1996. The ‘typical’ pasture treatment mimicked the pasture and grazing management common in the region, with volunteer annual-based pastures fertilised with around 5 kg/ha phosphorus (P) each year. The ‘upgraded’ pasture treatments were resown to phalaris, perennial ryegrass and subterranean clover, and higher rates of fertiliser (13–25 kg P/ha.year) plus other nutrients were applied. Both pastures were set stocked with the participating farmers breeding ewes. Stocking rate was an emergent variable on each plot. The stocking rate on the typical treatments was based on normal farm practise. Initially, the stocking rate of the upgraded pastures was 15% higher than for the typical pastures and increased over time depending if the ewes in the upgraded pastures were heavier than those in the typical pastures. Measurements included soil fertility, pasture production, nutritive value and composition, and animal production.
Net annual pasture production of the upgraded pastures was 10 500 kg/ha compared with 8700 kg/ha for the typical pastures. This average difference (18%) between the treatments was greatly influenced by the large advantage (40%) of the upgraded pasture in the wet year of 1992. Upgraded pastures had higher pasture production than typical pastures in spring but the reverse occurred in autumn. In a separate small plot experiment, the response of each pasture to higher P fertiliser applications was tested. In autumn and winter, there was a significant interaction between pasture type and P rate, with higher responses on the upgraded pastures. In spring, both pastures responded to increased P applications but the upgraded pastures were more responsive at all P rates. The upgraded pastures contained significantly higher legume content (30–50%) than the typical pastures (10–20%). The proportion of sown perennial grasses in the upgraded pasture declined from around 30 to 10% after 6 years displaced by annual grasses and broad-leaf weeds. Herbage from upgraded pastures had significantly higher crude protein content (2–7 units) and digestibility (1–10 units) than the typical pastures with the difference between the treatments increasing over time.
The set stocking policy used in this experiment is likely to have exacerbated the decline in sown perennial grasses and implementation of some form of strategic or rotational grazing may have improved persistence. The experiment also highlights the importance of selecting perennial grasses able to cope with the local environment and grazing conditions. Despite the decline in perennials, these results show significant potential to improve pasture productivity and quality in south-western Victoria.
Stress-strain properties of individual Merino wool fibres are minor contributors to variations in staple strength induced by genetic selection and nutritional manipulation
Authors: Thompson A. N. , Hynd P. I.
Published: July 2009

This paper investigates the contribution of single fibre stress-strain properties to variations in staple strength induced by both selective breeding for staple strength and nutritional manipulation. Merino weaners (n = 40), selected from ‘sound’ and ‘tender’ lines of staple strength selection flocks, were allocated to feeding regimes designed to induce liveweight changes simulating typical Mediterranean seasonal changes. Average staple strength differed by 5 N/ktex between ‘sound’ and ‘tender’ selection flocks and 18 N/ktex between extreme nutritional treatments. The force-extension properties of individual wool fibres (n = 100 per sheep) were measured using a single fibre strength meter. After normalising for differences in fibre cross-sectional area at the point of break, the key parameters used to describe the stress-strain curve for each fibre were: Young’s modulus (GPa), yield stress (MPa), stress at 15% strain (MPa), stress at break (MPa), strain at break (%) and work to break (MPa).
The average stress-strain properties of single fibres differed widely between individual sheep. Stress at break ranged from 163 to 235 MPa (44% range), strain at break ranged from 21 to 44% (103% range) and work to break from 43 to 71 MPa (65% range). There were no significant differences in any of the single fibre properties between the staple strength selection flocks, nor was there any significant interaction (P > 0.05) between staple strength selection flock and nutritional regimes. Nutritional regime had a significant effect on stress at break, strain at break and work to break, but none of the single fibre stress-strain properties removed any appreciable variance in staple strength over and above that accounted for by differences in along- and between-fibre diameter variation. There appears to be little scope for improvement of single fibre stress-strain properties as a means of increasing staple strength in normal production environments. Selection directly for staple strength or indirectly using the fibre diameter variability traits is an effective method to improve staple strength.
Evaluation of equipment for breeding does housed under Australian meat rabbit farming conditions
Authors: Eady S. J.
Published: July 2009

Two experiments yielded practical recommendations on design of cage equipment (mats and nest boxes) that can potentially improve the welfare and productivity of breeding does. The results show that, in the environment experienced by the experimental rabbits, sore hocks (pododermatitis) can be reduced in breeding does from an incidence of 4% down to less than 1%, by the provision of suitable pressure mats. The difference between the highest and lowest performing nest boxes, in terms of number of kittens weaned, translates into a difference in enterprise gross margins of A$52.35 per doe per annum, or an increase of 36% in profit from the use of the best performing nest box compared with the worst. Farmers can use the results as a guide to choosing or constructing nest box equipment, and should be encouraged to objectively compare different designs under their own environmental conditions.
Restructuring of the Australian chicken industry: identification of risk factors for the closure of farms
Authors: East I. J. , Hamilton S. A.
Published: July 2009

We conducted a cross-sectional survey of 760 Australian layer chicken farms to identify risk factors associated with the closure of poultry farms. Address data and operating status were obtained for 734 farms and more detailed responses on farm size, structure and management practices from 317 farms (41.7%). The overall prevalence of closed farms was 36.4%. Increased risk of closure was associated with independent ownership [odds ratio (OR) = 2.22, P < 0.01], location within 50 km of the centre of a state capital city (OR = 1.66, P < 0.01), being a layer farm that reared its own pullets (OR = 2.18, P < 0.01) and location within Queensland or South Australia (OR = 3.10, 3.56; both P < 0.01). Analysis of the subset of farms for which more detailed information was available identified location in South Australia (OR = 9.23, P < 0.01), use of cages (OR = 4.36, P < 0.01) and sheds with only natural ventilation (OR = 11.00, P < 0.02) as risk factors associated with a greater risk of farm closure. Our survey found that closed farms were typically independently owned, cage-layer farms located in peri-urban regions near major cities and utilising sheds without assisted ventilation.
Multigrain seabed sediment transport modelling for the south-west Australian Shelf
Authors: Li F. , Griffiths C. M. , Dyt C. P. , Weill P. , Feng M. , Salles T. , Jenkins C.
Published: July 2009

With increasing concerns about climate change and sea-level rise, there is a need for a comprehensive understanding of the sedimentary processes involved in the erosion, transport and deposition of sediment on the continental shelf. In the present paper, long-term and large-scale seabed morphological changes on the south-west Australian continental shelf were investigated by a comprehensive sediment transport model, Sedsim. The investigated area covers the continental shelf and abyssal basins of the south-western region. The regional seabed is sensitive to environmental forces and sediment supply, and most terrigenous sediment carried down by major rivers is trapped in inland lakes or estuaries. Only a small fraction of fine-grain sediment reaches the continental shelf. The simulation has also confirmed that the Leeuwin Current and high-energy waves play the most important roles in regional long-term seabed evolution. Although the numerical implementation only approximates some forcing and responses, it represents a significant step forward in understanding the nature of potential long-term seabed change as a response to possible climate change scenarios. The 50-year forecast on the seabed morphological changes provides a reference for the management of coastal and offshore resources, as well as infrastructure, in a sustainable way.
Using caesium-137 and unsupported lead-210 measurements to explore the relationship between sediment mobilisation, sediment delivery and sediment yield for a Calabrian catchment
Authors: Porto Paolo , Walling Des E. , Callegari Giovanni , Capra Antonina
Published: July 2009

Recent concern about the many environmental problems associated with the transport of fine sediment by rivers has generated a need to obtain spatially distributed evidence of the erosion rates operating within a catchment and to explore more explicitly the links between sediment mobilisation, transfer, storage and output. In the past few decades, the fallout radionuclides caesium-137 (137Cs) and unsupported lead-210 (210Pbex) have been successfully used as tracers to estimate soil erosion and deposition rates in many areas of the world. However, to date, most studies using this approach have focussed on relatively small areas, such as individual fields or small catchments. There is a need to explore the potential for upscaling the approach to larger areas or catchments. The present paper reports an attempt to use the fallout radionuclides 137Cs and 210Pbex to explore further the relationship between sediment mobilisation, sediment transfer and storage, and sediment yield for a medium-scale (31.61 km2) catchment located in Calabria, southern Italy. The results emphasise that the low value of specific sediment yield derived for the study catchment from measurements of the suspended sediment flux at the catchment outlet obscure the existence of appreciable erosion rates in many areas of the catchment. Much of this erosion is balanced by deposition and sediment storage, resulting in a relatively low sediment delivery ratio for the catchment.
Diurnal sediment resuspension and settling: impact on the coupled physical and biogeochemical dynamics of dissolved oxygen and carbon in a shallow water body
Authors: Branco Brett F. , Torgersen Thomas
Published: July 2009

Small, shallow, inland water bodies are ubiquitous on the landscape and may be significant hotspots for biogeochemical transformations. However, the coupled physical and biogeochemical dynamics of these systems have received little attention compared with larger and deeper systems. Here, we examine the coupling between physical dynamics, sediment dynamics and oxygen–carbon dynamics in Mirror Lake, a small shallow pond in Storrs, CT, USA, using high frequency monitoring data and a simple coupled physical–biogeochemical model. The physical dynamics are characterised by a diurnal pattern of daytime thermal stratification and nighttime mixing. Observations show that the distribution of oxygen is tightly coupled with both the diurnal physical dynamics and photosynthesis–respiration reactions. Two 24-h periods in the summer of 2003 with similar meteorological conditions but distinctly different oxygen dynamics were simulated with a coupled physical–biogeochemical model. The model results suggest that the dynamics of sediment resuspension during nighttime convective overturn and subsequent settling during daytime stratification are critical in explaining the observed oxygen and dissolved inorganic carbon distributions. The diurnal dynamics provide a biogeochemical hot spot and hot moment by coupling meterologic forcing, resuspension of sediments, physical mixing and biological activity to hypoxia and anoxia in Mirror Lake.
Orangutans employ unique strategies to control branch flexibility
Authors: Thorpe Susannah K. S. , Holder Roger , Crompton Robin H.
Published: July 2009

Orangutans are the largest habitually arboreal mammal. For them, as for all arboreal mammals, access to the abundant fruits and narrowest gaps found among the thin peripheral branches of tree crowns poses considerable safety risks and energetic demands. Most arboreal primates use flexed-limb postures to minimize problems caused by branch compliance and instability. Here, we show that Sumatran orangutans employ unique locomotor strategies to control compliance and allow access to the terminal branch niche for feeding and gap crossing. We calculated a “stiffness score,” which is a measure of the flexibility of the supports on which orangutans moved. We found that certain locomotor behaviors clearly are associated with the most compliant supports; these behaviors appear to lack regular limb sequences, which serves to avoid the risk of resonance in branch sway caused by high-frequency, patterned gait. Balance and increased stability are achieved through long contact times between multiple limbs and supports and a combination of pronograde (horizontal) and orthograde (vertical) body postures, used both above branches and in suspension underneath them. Overall, adult females seem to be the most conservative in their travel, selecting more solid and secure supports than males and adolescents. These results have implications for understanding locomotor diversity in fossil and extant apes and for orangutan conservation and reintroduction programs.
Genomic analysis reveals few genetic alterations in pediatric acute myeloid leukemia
Authors: Radtke Ina , Mullighan Charles G. , Ishii Masami , Su Xiaoping , Cheng Jinjun , Ma Jing , Ganti Ramapriya , Cai Zhongling , Goorha Salil , Pounds Stanley B. , Cao Xueyuan , Obert Caroline , Armstrong Jianling , Zhang Jinghui , Song Guangchun , Ribeiro Raul C. , Rubnitz Jeffrey E. , Raimondi Susana C. , Shurtleff Sheila A. , Downing James R.
Published: July 2009

Pediatric de novo acute myeloid leukemia (AML) is an aggressive malignancy with current therapy resulting in cure rates of only 60%. To better understand the cause of the marked heterogeneity in therapeutic response and to identify new prognostic markers and therapeutic targets a comprehensive list of the genetic mutations that underlie the pathogenesis of AML is needed. To approach this goal, we examined diagnostic leukemic samples from a cohort of 111 children with de novo AML using single-nucleotide-polymorphism microarrays and candidate gene resequencing. Our data demonstrate that, in contrast to pediatric acute lymphoblastic leukemia (ALL), de novo AML is characterized by a very low burden of genomic alterations, with a mean of only 2.38 somatic copy-number alterations per leukemia, and less than 1 nonsynonymous point mutation per leukemia in the 25 genes analyzed. Even more surprising was the observation that 34% of the leukemias lacked any identifiable copy-number alterations, and 28% of the leukemias with recurrent translocations lacked any identifiable sequence or numerical abnormalities. The only exception to the presence of few mutations was acute megakaryocytic leukemias, with the majority of these leukemias being characterized by a high number of copy-number alterations but rare point mutations. Despite the low overall number of lesions across the patient cohort, novel recurring regions of genetic alteration were identified that harbor known, and potential new cancer genes. These data reflect a remarkably low burden of genomic alterations within pediatric de novo AML, which is in stark contrast to most other human malignancies.
Influence of glycemic control on fetal lung maturity in gestations affected by diabetes or mild hyperglycemia
Authors: DE LUCA ANA KARINA CRISTIUMA , NAKAZAWA CRISTIANE YOSHIE , AZEVEDO BEATRIZ CAMARGO , RUDGE MARILZA VIEIRA CUNHA , DE ARAÚJO COSTA ROBERTO ANTONIO , CALDERON IRACEMA MATTOS PARANHOS
Published: July 2009

Objective. To evaluate the influence of glycemic control on fetal lung maturity in pregnancies affected by diabetes or mild hyperglycemia. Design. Cross‐sectional study. Setting. Level III maternity center. Population. A total of 187 pregnant women were submitted to routine amniocentesis for the assessment of fetal lung maturity up to 72 hours before delivery. Methods. Fetal lung maturity thresholds were: Clements‐positive at a dilution of 0.5; OD650 nm≥0.15; and lamellar body count (LBC) ≥ 32,000/μl. The relation of test results with adequate (≤6.7 mmol/l) or poor (>6.7 mmol/l) glycemic mean (GM) at term and at preterm was evaluated. Main outcome measure. Delay in fetal lung maturity when glycemic control was poor. Results. Glycemic control was adequate in 146 (78.1%) women. Clements maturity rates were higher at term (91.9%) than at preterm (64.7%) when GM ≤ 6.7 mmol/l (p<0.001), but not when control was inadequate. LBC median was higher at term (99.0; 62.0–154.0) than at preterm (66.5; 40.5–108.25) (p = 0.009) when GM ≤ 6.7 mmol/l, while GM > 6.7 mmol/l did not lead to any difference between these rates at term or preterm. When glycemic control was adequate, OD650 nm medians at term and at preterm were similar. However, when GM >6.7 mmol/l, OD650 nm median at term (0.29; 0.22–0.40) was higher than that observed at preterm (0.15; 0.12–0.18) (p<0.001). Conclusions. Our results suggest that in term pregnancies routine amniocentesis for the assessment of fetal lung maturity should be abandoned. In preterm pregnancies, or when glycemic control is inadequate it is recommended.
Reliability of magnetic resonance imaging in assessing myometrial invasion absence in endometrial carcinoma
Authors: SUH DAE‐SHIK , KIM JEONG KON , KIM KYU RAE , KIM DAE‐YEON , KIM JONG‐HYEOK , KIM YONG‐MAN , KIM YOUNG‐TAK , NAM JOO‐HYUN
Published: July 2009

Objective. This study evaluated the reliability of magnetic resonance imaging (MRI) in assessing the absence of myometrial invasion in endometrial carcinoma patients, to identify candidates for conservative hormonal treatment. Methods. A total of 301 endometrial carcinoma patients who showed Stage I findings on preoperative MRI, and had received staging operations were reviewed retrospectively. We compared MRI findings of myometrial invasion with myometrial invasion levels reported by pathologists when surgical specimens were examined. Design. A descriptive study. Setting. Tertiary care gynecologic oncology clinic, Seoul, Korea. Population. A total of 301 endometrial carcinoma patients who showed Stage I findings on preoperative MRI, and had received staging operations. Main outcome measure. We compared MRI findings of myometrial invasion with myometrial invasion levels reported by pathologists when surgical specimens were examined. Results. Of 301 patients, 17 showed higher stages (FIGO Stages IIA through IIIC) on the final pathology of surgical specimen. Among the 284 patients with Stage I on histology reports, 124 showed no myometrial invasion on preoperative MRI (FIGO Stage IA). The negative predictive value (probability of absence of myometrial invasion) was 49.2%. MRI showed an accuracy of 59.2%, a sensitivity of 68.8%, a specificity of 74.4%, and an 86.9% positive predictive value, for myometrial invasion. Conclusions. MRI had a rather weak predictive value when used to assess absence of myometrial invasion. This should be borne in mind when choosing patients for conservative treatment of endometrial carcinoma.
Association between experiencing rape, police reporting, and self‐reported health among women visiting three gynecology clinics in Sweden
Authors: DAVIDSSON JOHANNA , BENJAMINSSON GABRIELLA , WIJMA BARBRO , SWAHNBERG KATARINA
Published: July 2009

Objective. To describe the frequency of police reporting among rape victims based on two hypotheses: (1) victims of rape more often report poor health than those who have not been victims of any abuse, and (2) victims who report abuse to the police are more likely to state poor self‐reported health than those who do not report any abuse. Design. Cross‐sectional questionnaire study. Setting. Three Swedish departments of obstetrics and gynecology. Sample. From an original sample of 2,439 women, those who had experienced rape and those who had no history of abuse were included (n = 1,319). Method. Analysis of associations between self‐reported poor health, rape, and police reporting among rape victims were assessed by multivariate models adjusted for type of abuse, perpetrator, and sociodemographic factors. Main outcome measures. Odds ratios (ORs) for poor health among rape victims. Results. Rape was seldom reported to the police (23.5%, 44/187). Both hypotheses were confirmed; rape victims more often state poor health than non‐abused women (adjusted OR 3.9; 95% confidence interval (CI) 2.4–6.3), and women who had reported abuse to the police stated poor health more often than those who had not reported abuse to the police (adjusted OR 3.0; 95% CI 1.1–8.1). Conclusions. Three of four rape victims had not reported any abuse to the police, and those who had were more likely to report poor health. Rape myths are prevalent in society and affect how victims of sexual abuse are treated both by formal and informal support providers, which in turn may affect the recovery and health of victims. Our results send an urgent message to the current debate on sexual abuse against women: Why do women not report rape to the police?
Significance of sonographic characterization for managing subcentimeter thyroid nodules
Authors: Kwak Jin Young , Kim Eun-Kyung , Kim Min Jung , Son Eun Ju
Published: July 2009

Background: Ultrasonography (US) is increasingly able to detect thyroid nodules, and the differentiation between malignant and benign nodules has been raising issues among both clinicians and patients, especially patients with non-palpable small nodules. It is important to diagnose thyroid cancer at an early stage, because it may reduce the risk of disease recurrence and possible mortality.

Purpose: To evaluate the diagnostic accuracy of malignant sonographic features of subcentimeter thyroid nodules.

Material and Methods: This study examined 815 subcentimeter thyroid nodules in 815 patients. A final diagnosis was determined using fine-needle aspiration biopsy (FNAB) or postoperative pathologic findings. Logistic regression tests were used to evaluate statistical relationships between US findings and thyroid carcinoma.

Results: Of 534 lesions that showed suspicious US findings, 472 (88.4%) revealed malignancy upon cytopathology. Two hundred eighty-one lesions showed probably benign findings on US, and only 23 (8.2%) were malignant. Sensitivity, specificity, positive predictive value, and negative predictive value of US were 95.4%, 80.6%, 88.4%, and 91.8%, respectively. There was a significant difference between the two US groups in the percentages of malignancy, according to logistic regression analysis.

Conclusion: Our results demonstrate that this system of US classification can efficiently differentiate malignant subcentimeter nodules from benign nodules. Suspicious sonographic features can be useful criteria to decide whether a nodule should receive FNAB.
A dynamic infrared imaging-based diagnostic process for breast cancer
Authors: Joro R. , Lääperi A.-L. , Dastidar P. , Järvenpää R. , Kuukasjärvi T. , Toivonen T. , Saaristo R. , Soimakallio S.
Published: July 2009

Background: Dynamic infrared (IR) imaging is an emerging functional imaging modality for the detection of breast cancer without evidence of optimal imaging and diagnostic application.

Purpose: To evaluate dynamic IR imaging in breast cancer diagnostics by comparing a stepwise diagnostic scheme to digital mammography and postoperative histopathology.

Material and Methods: Dynamic IR imaging of breasts was undertaken preoperatively with a long-wave quantum well (QWIP) and two mid-wave photovoltaic (PV) IR cameras in 10 cases (age 34–80 years) with breast cancer size 6–45 mm on mammography. Image stabilization, two-phase frequency analysis, and two image-processing algorithms were applied.

Results: Combining image processing with frequency analysis proved advantageous in detecting breast cancer. The IR imaging process recognized the cancer area independently of tissue density, cancer size, and cancer appearance on mammography. Compared to histopathology, all cancers yielded abnormal analysis results, including one case of ductal carcinoma in situ. Evidence of lymphatic invasion in postoperative histopathology, imaging with PV camera, and image processing with the Wiener filtering combination correlated with highest confidence between normal and cancer tissue measured by the calculated superiority value.

Conclusion: Dynamic IR imaging with image-processing-guided frequency analysis is a promising modality for breast cancer detection and may not have the tissue-dependent limitations of mammography. Our results encourage further work on medical IR imaging and comparison to established breast-imaging modalities.