bluuebunny/crossref_metadata_2025 huggingface dataset:
Explicit global simulation of the mesoscale spectrum of atmospheric motions
Authors: Takahashi Yoshiyuki O. , Hamilton Kevin , Ohfuchi Wataru
Published: June 2006

The horizontal spectrum of kinetic energy in the upper troposphere in experiments conducted with the Atmospheric GCM for the Earth Simulator (AFES) global spectral general circulation model is examined. We find that the control version of AFES run at T639 spectral resolution can simulate a realistic kinetic energy spectrum with roughly −3 power‐law dependence on horizontal wavenumber for wavelengths between about 5000 and 500 km, transitioning to a shallower mesoscale regime at smaller wavelengths. The results depend to a degree on the magnitude of the parameterized horizontal hyperdiffusion, but the existence of a distinct shallow mesoscale range in the simulations is independent of the hyperdiffusion employed. We present results from a number of AFES integrations with spectral truncations ranging from T39 to T639 and determine the appropriate scaling of the parametrized hyperdiffusion with model numerical resolution so that the kinetic energy spectrum in each case converges to realistic values. The experiment was also repeated in a dry version of the model. This version also simulated a shallow mesoscale range, supporting the view that the mesoscale regime in the atmosphere is energized, at least in part, by a predominantly downscale nonlinear spectral cascade.
Atlantic hurricanes and natural variability in 2005
Authors: Trenberth Kevin E. , Shea Dennis J.
Published: June 2006

The 2005 North Atlantic hurricane season (1 June to 30 November) was the most active on record by several measures, surpassing the very active season of 2004 and causing an unprecedented level of damage. Sea surface temperatures (SSTs) in the tropical North Atlantic (TNA) region critical for hurricanes (10° to 20°N) were at record high levels in the extended summer (June to October) of 2005 at 0.9°C above the 1901–70 normal and were a major reason for the record hurricane season. Changes in TNA SSTs are associated with a pattern of natural variation known as the Atlantic Multi‐decadal Oscillation (AMO). However, previous AMO indices are conflated with linear trends and a revised AMO index accounts for between 0 and 0.1°C of the 2005 SST anomaly. About 0.45°C of the SST anomaly is common to global SST and is thus linked to global warming and, based on regression, about 0.2°C stemmed from after‐effects of the 2004–05 El Niño.
Influence of watershed glacier coverage on summer streamflow in British Columbia, Canada
Authors: Stahl K. , Moore R. D.
Published: June 2006

This study examined the effects of glacier cover on summer streamflow across British Columbia, Canada, by applying nonparametric tests to assess trends in August discharge. Field‐significant negative streamflow trends were found for glacierized catchments but not for those lacking glaciers. Effects of interannual climatic variations were accounted for by regressing August streamflow against August temperature and precipitation and July streamflow (to account for carryover storage). Trend analyses of the regression residuals suggested first‐order stationarity for unglacierized basins, but revealed widespread negative trends for glacier‐fed rivers, particularly from 1976 to 1996, consistent with the effects of glacier retreat.
The role of constitutive PKA‐mediated phosphorylation in the regulation of basal ICa in isolated rat cardiac myocytes
Authors: Bracken Nicolas , ElKadri Moutaz , Hart George , Hussain Munir
Published: June 2006

Pharmacological inhibitors of protein kinase A (PKA) and protein phosphatases 1/2A were used to determine whether basal L‐type Ca2+ current (ICa) observed in the absence of exogenous β‐adrenergic receptor stimulation is sustained by PKA‐mediated phosphorylation. Amphotericin B was used to record whole‐cell ICa in the perforated patch‐clamp configuration.

Calyculin A and isoprenaline (both 1 μmol l−1) increased basal ICa (P<0.05), whereas H‐89 inhibited ICa in a concentration‐dependent manner with an IC50 ∼5 μmol l−1. H‐89 also inhibited the response to 1.0 μmol l−1 isoprenaline, although relatively high concentrations (30 μmol l−1) were required to achieve complete suppression of the response.

Double‐pulse protocols were used to study the effects of 10 μmol l−1 H‐89 on time‐dependent recovery of ICa from voltage‐dependent inactivation as well as the steady‐state gating of ICa. T0.5 (time for ICa to recover to 50% of the preinactivation amplitude) increased in the presence of H‐89 (P<0.05) but was unaffected by calyculin A or isoprenaline.

Steady‐state activation/inactivation properties of ICa were unaffected by 10 μmol l−1 H‐89 or 1 μmol l−1 calyculin A, whereas isoprenaline caused a leftward shift in both curves so that V0.5 for activation and inactivation became more negative.

Data show that basal ICa is regulated by cAMP‐PKA‐mediated phosphorylation in the absence of externally applied β‐receptor agonists and that relatively high concentrations of H‐89 are required to fully suppress the response to β‐adrenergic receptor stimulation, thereby limiting the value of H‐89 as a useful tool in dissecting signalling pathways in intact myocytes.

British Journal of Pharmacology (2006) 148, 1108–1115. doi:10.1038/sj.bjp.0706809
H‐89 inhibits transient outward and inward rectifier potassium currents in isolated rat ventricular myocytes
Authors: Pearman Charles , Kent William , Bracken Nicolas , Hussain Munir
Published: June 2006

Voltage clamp was used to investigate the effects of N‐[2‐p‐bromo‐cinnamylamino)ethyl]‐5‐isoquinolinesulfonamide (H‐89), a potent inhibitor of PKA, on transient outward K+ current (Ito) and inward rectifying K+ current (IK1) in rat cardiac muscle.

Initial experiments, performed using descending voltage ramps, showed that H‐89 inhibited both the outward and inward ramp currents in a concentration‐dependent manner at concentrations between 5 and 60 μmol l−1. A similar degree of inhibition was observed when Ito and IK1 were recorded using square wave depolarising and hyperpolarising voltage steps, respectively.

The IC50 was 35.8 μmol l−1 for Ito and 27.8 μmol l−1 for IK1 compared to 5.4 μmol l−1 for L‐type Ca2+ current (ICa). The Hill coefficients for Ito, IK1 and ICa were −1.97, −1.60 and −1.21, respectively. In addition to inhibiting Ito amplitude, H‐89 also accelerated the time to peak and the rate of voltage‐dependent inactivation so that the time course of Ito was abbreviated.

Paired‐pulse protocols were performed to study the effects of H‐89 on steady‐state activation and inactivation as well as recovery from voltage‐dependent inactivation. H‐89 produced a concentration‐dependent rightward shift in voltage‐dependent activation but had no significant effect on steady‐state inactivation. Recovery from voltage‐dependent inactivation was delayed, although this was only visible at the highest concentration (60 μmol l−1) used.

In experiments investigating the effects of elevated cyclic AMP, the β‐adrenergic agonist isoprenaline and the phosphatase inhibitor calyculin A had no major effects on Ito or IK1.

Data suggest that the effects of H‐89 on K+ currents are more complex than simple inhibition of PKA‐mediated phosphorylation.

British Journal of Pharmacology (2006) 148, 1091–1098. doi:10.1038/sj.bjp.0706810
GHZ extraction yield for multipartite stabilizer states
Authors: Bravyi Sergey , Fattal David , Gottesman Daniel
Published: June 2006

Let ∣Ψ⟩ be an arbitrary stabilizer state distributed between three remote parties, such that each party holds several qubits. Let S be a stabilizer group of ∣Ψ⟩. We show that ∣Ψ⟩ can be converted by local unitaries into a collection of singlets, GHZ states, and local one-qubit states. The numbers of singlets and GHZs are determined by dimensions of certain subgroups of S. For an arbitrary number of parties m we find a formula for the maximal number of m-partite GHZ states that can be extracted from ∣Ψ⟩ by local unitaries. A connection with earlier introduced measures of multipartite correlations is made. An example of an undecomposable four-party stabilizer state with more than one qubit per party is given. These results are derived from a general theoretical framework that allows one to study interconversion of multipartite stabilizer states by local Clifford group operators. As a simple application, we study three-party entanglement in two-dimensional lattice models that can be exactly solved by the stabilizer formalism.
Hybrid quantum/classical molecular dynamics for a proton transfer reaction coupled to a dissipative bath
Authors: Kim Soo Young , Hammes-Schiffer Sharon
Published: June 2006

A hybrid quantum/classical molecular dynamics approach is applied to a proton transfer reaction represented by a symmetric double well system coupled to a dissipative bath. In this approach, the proton is treated quantum mechanically and all bath modes are treated classically. The transition state theory rate constant is obtained from the potential of mean force, which is generated along a collective reaction coordinate with umbrella sampling techniques. The transmission coefficient, which accounts for dynamical recrossings of the dividing surface, is calculated with a reactive flux approach combined with the molecular dynamics with quantum transitions surface hopping method. The hybrid quantum/classical results agree well with numerically exact results in the spatial-diffusion-controlled regime, which is most relevant for proton transfer in proteins. This hybrid quantum/classical approach has already been shown to be computationally practical for studying proton transfer in large biological systems. These results have important implications for future applications to hydrogen transfer reactions in solution and proteins.
The methyl C–H blueshift in N,N-dimethylformamide-water mixtures probed by two-dimensional Fourier-transform infrared spectroscopy
Authors: Xu Zheng , Li Haoran , Wang Congmin , Pan Haihua , Han Shijun
Published: June 2006

Two-dimensional correlation spectroscopy was used to study the composition-dependent spectral variations of the CH-stretching bands of N,N-dimethylformamide (DMF)-water mixtures with XDMF ranging from 0.98 to 0.60. By a detailed correlation analysis of the spectral changes of the CH- and OH-stretching bands, it is found that the intensities of the CH and OH bands change in different ways when the water content is increased. It is also found that two different regions of the water content can be distinguished, in which the intensity changes have different signatures. A tentative explanation for how these phenomena might be related to structural changes in the mixture is proposed. The structural change of DMF induced by the water hydrogen bonded on the carbonyl group is supposed to be the possible origin of the methyl C–H blueshift instead of the direct C–H⋯O interactions before the hydrophobic hydration takes place.
Low-voltage high-mobility pentacene thin-film transistors with polymer/high-k oxide double gate dielectrics
Authors: Hwang D. K. , Lee Kimoon , Kim Jae Hoon , Im Seongil , Kim Chang Su , Baik Hong Koo , Park Ji Hoon , Kim Eugene
Published: June 2006

We report on the fabrication of pentacene-based thin-film transistors (TFTs) with poly-4-vinylphenol (PVP)/yttrium oxide (YOx) double gate insulator films. The minimum PVP and YOx layer thicknesses were chosen to be 45 and 50nm, respectively. The PVP and YOx double dielectric layers with the minimum thicknesses exhibited a high dielectric capacitance of 70.8nF∕cm2 and quite a good dielectric strength of ∼2MV∕cm at a leakage current level of ∼10−6A∕cm2 while the leakage current from either PVP or YOx alone was too high. Our pentacene TFTs with the 45nm thin PVP∕50nm thin YOx films operated at −5V showing a high field effect mobility of 1.74cm2∕Vs and a decent on/off current ratio of 104. Our work demonstrates that the PVP∕YOx double layer is a promising gate dielectric to realize low-voltage high-mobility organic TFTs.
Complete infrared spectroscopic characterization of phenol-borane-trimethylamine dihydrogen-bonded complex in the gas phase
Authors: Patwari G. Naresh , Fujii Asuka , Mikami Naohiko
Published: June 2006

In the paper we report the first observation of the vibrational spectrum in the B–H stretching region in the gas phase for a dihydrogen bonded complex. The appearance of three transitions for the B–H stretching modes of a (di)hydrogen-bonded complex involving borane-trimethylamine indicates the lowering of the symmetry on the BH3 group upon interaction with phenol. Further, the shift in the O–H stretching frequency indicates that phenol is hydrogen bonded to borane-trimethylamine. The two sets of the present data establish, unequivocally, the formation of O–H⋯H–B dihydrogen-bonded complex between phenol and borane-trimethylamine.
Rotating cryogenic drum supplying solid Xe target to generate extreme ultraviolet radiation
Authors: Fukugaki Keisuke , Amano Sho , Shimoura Atushi , Inoue Takahiro , Miyamoto Shuji , Mochizuki Takayasu
Published: June 2006

In order to generate high-average-power extreme ultraviolet radiation around 13.5nm from laser-produced plasma, a fast rotating cryogenic drum system which can continuously supply a solid Xe target for high-repetition laser pulses has been developed. It was successfully operated at a rotating speed of 1000rpm and an up-down speed of 3mm∕s. The growth rate of the solid Xe layer is kept at a constant speed (for example, 18μm∕s) with a constant rate of Xe input flow, independent of the rotating speed. It has been demonstrated that wipers play an important role in recovering the laser craters with a recovery rate of 150μm∕s. These performances allow laser illuminations on the solid Xe target with a pulse repetition rate of 10kHz without overlapping laser craters.
Thermal limits on field alignment of nanoparticle FePt media
Authors: Bain James A. , Egelhoff William F.
Published: June 2006

We derive a simple expression for the average angular orientation distribution of ferromagnetic FePt particles in an applied field in thermal equilibrium. This system is closely related to the Langevin expression for paramagnetic susceptibility, which computes the average orientation of particles in this configuration. We note that practical fields are unlikely to be able to provide well-aligned arrays of the smallest thermally stable FePt particles at room temperature and that this has significant consequences for self-organized nanoparticle magnetic media. It suggests that it may be difficult to obtain an acceptable degree of perfection in orientation for the smallest particles.
Superhydrophobic behavior of fluorinated carbon nanofiber arrays
Authors: Hsieh Chien-Te , Fan Wen-Syuan
Published: June 2006

Superhydrophobic behavior of fluorinated carbon nanofiber (CNF) arrays, prepared by a template-assisted synthesis, has been investigated. A thermal chemical vapor method, using perfluorohexane as the precursor, was used to coat fluorocarbon on the surface of the CNFs, thus lowering their surface tension. The F-coated CNFs exhibited a good water-repellent behavior, i.e., the highest value of contact angle ∼166°. The superhydrophobicity of water droplets on the arrays can be well predicted by a modified Cassie-Baxter model, incorporating the pore size distributions determined from the density functional theory method. This satisfactory result would shed one light on how the variation of opened sizes would induce the superhydrophobicity of nanostructured surfaces.
Quality of the reconstruction in x-ray phase contrast tomography
Authors: Arhatari B. D. , Peele A. G. , Nugent K. A. , De Carlo F.
Published: June 2006

We develop an analytical model for three dimensional phase contrast tomography for a pure phase object. The model incorporates an extended source, which is suitable for a laboratory based microfocus x-ray source. From the modeled intensities for the tomographic data set we obtain a model reconstruction and define a reconstruction quality factor that allows us to optimize the tomographic reconstruction for given feature sizes in an object.
Closed loop applied to magnetic measurements in the range of 0.1–50MHz
Authors: Cavoit Claude
Published: June 2006

After a brief historical review of inductive sensors used for measuring terrestrial magnetic field variations, this article explains the difficulty in extending the working range of the well known search coil toward high frequencies. The theory of the closed loop magnetometer is exposed and practical considerations leading to an optimized sensor are discussed. Two examples of prototypes are then shown, with the simulated and experimental curves of the transfer function and the noise spectral density. Finally, an experimental facility to measure the sensitivity of the sensor to the pure electric field is shown, and the results of one of the prototypes are presented.
Pixel-encapsulated flexible displays with a multifunctional elastomer substrate for self-aligning liquid crystals
Authors: Kim Yeun-Tae , Hong Jong-Ho , Yoon Tae-Young , Lee Sin-Doo
Published: June 2006

We report on a pixel-encapsulated flexible liquid crystal display (LCD) based on an elastomer substrate of self-aligning LC molecules. The elastomer substrate, fabricated by a replica molding technique, has pixel-encapsulating walls that serve as spacers and allow for mechanical stability and reproducibility against bending deformations. Our pixel-encapsulated LCD provides great flexibility, durability, and excellent electro-optic performances in a highly bent environment.
Temperature-dependent dark current measurements in GaAsN heterojunction diodes
Authors: Luther J. M. , Johnston S. W. , Kurtz S. R. , Ahrenkiel R. K. , Collins R. T.
Published: June 2006

Temperature- and bias-dependent current measurements were performed on n+-GaAs∕p-GaAs1−xNx heterojunction diodes. The samples studied are in the dilute regime and contain less than 1.7% nitrogen with respect to arsenic. Current-voltage, thermally stimulated current, and current transient (after voltage change) measurements provide unique insight into the defect participation in carrier transport within the depletion region. We will present the data obtained from these measurements, which show an activation energy of 0.21eV and may be related to a key defect measured by capacitance transients in the literature.
Experimental investigation of transport properties in chalcogenide materials through 1∕f noise measurements
Authors: Fantini P. , Pirovano A. , Ventrice D. , Redaelli A.
Published: June 2006

Low-frequency noise spectral density in chalcogenide-based phase-change memory cells has been measured, discussing the role of trapping centers and static disorder as responsible for a noise level in the vitreous insulating state two orders of magnitude higher than in the ordered conducting polycrystalline one. The magnitude of 1∕f noise has been also studied as a function of the applied voltage and exploited to experimentally investigate the transport mechanisms in chalcogenide alloys, showing that the exponential increase of noise spectral density with voltage can be quantitatively explained by considering an avalanchelike multiplication phenomenon.
Spin dynamics in a diluted magnetic semiconductor quantum well studied by pump-probe absorption spectroscopy: Magnetic-field-induced suppression of electron-spin relaxation
Authors: Murayama A. , Seo K. , Nishibayashi K. , Souma I. , Oka Y.
Published: June 2006

Exciton spin dynamics is studied in a diluted magnetic semiconductor quantum well of Cd0.95Mn0.05Te by pump-probe absorption spectroscopy under magnetic fields. The time dependences of the saturated absorbance for the higher- and lower-energy spin states of heavy-hole (hh) excitons clarify the following exciton-spin relaxation process in magnetic fields: ultrafast hh-spin relaxation with the formation of dark excitons and subsequent electron-spin relaxation. The electron-spin relaxation due to the s-d exchange mechanism involving Mn spins is suppressed in a high magnetic field by field-induced pinning of the Mn spins.
High-TC rf superconducting quantum interference device readout with a cryogenic preamplifier
Authors: He D. F. , Tachiki M. , Itozaki H.
Published: June 2006

A high-TC rf superconducting quantum interference device (SQUID) readout with a cryogenic preamplifier was developed. The noise figure of the preamplifier at 350MHz was about 0.92dB at room temperature and 0.35dB at 77K. For a high-TC yttrium barium copper oxide rf SQUID coupled with a lumped element tank circuit with a resonant frequency of about 360MHz, the white flux noise was about 25μΦ0∕√Hz and 22μΦ0∕√Hz when the preamplifier was at room temperature and at 77K, respectively. The flux noise was only reduced by about 12% using the cryogenic preamplifier. As the thermal noise of the SQUID and the noise generated by the tank circuit are already higher than the preamplifier noise, cooling the preamplifier has only a small effect of the system noise, when the SQUID is operated at 77K. Lower operating temperatures, e.g., when using a SQUID made from MgB2, might justify the use of a cooled preamplifier.
Noncontact electrical metrology of Cu/low-k interconnect for semiconductor production wafers
Authors: Talanov Vladimir V. , Scherz André , Schwartz Andrew R.
Published: June 2006

We have demonstrated a technique capable of in-line measurement of dielectric constant of low-k interconnect films on patterned wafers utilizing a test key of ∼50×50μm2 in size. The test key consists of a low-k film backed by a Cu grid with >50% metal pattern density and <0.25μm pitch, which is fully compatible with the existing dual-damascene interconnect manufacturing processes. The technique is based on a near-field scanned microwave probe and is noncontact, noninvasive, and requires no electrical contact to or grounding of the wafer under test. It yields <0.3% precision and ±2% accuracy for the film dielectric constant.
High-temperature ferromagnetism in Mn-doped ZnO nanowires
Authors: Philipose U. , Nair Selvakumar V. , Trudel Simon , de Souza C. F. , Aouba S. , Hill Ross H. , Ruda Harry E.
Published: June 2006

We have observed ferromagnetism in dilute (∼1–4at.%) Mn-doped crystalline ZnO nanowires at temperatures up to 400K. Arrays of freestanding single crystal ZnO:Mn nanowires were fabricated by Au-catalyzed vapor-liquid-solid growth. Structure and compositional analyses revealed that Mn was incorporated into the ZnO lattice. From the observed saturation magnetization, the magnetic moment per Mn atom is estimated to be between 0.3μB and 1.2μB. Photoluminescence measurements show a strong suppression of defect related midgap emission, indicative of an interplay between Mn doping and native point defects.
Room-temperature low-power hydrogen sensor based on a single tin dioxide nanobelt
Authors: Fields L. L. , Zheng J. P. , Cheng Y. , Xiong P.
Published: June 2006

Hydrogen sensors have been fabricated from single SnO2 nanobelts synthesized via catalyst-free thermal evaporation. Ohmic contacts were defined on individual SnO2 nanobelts by photolithography and pulsed laser deposition of RuO2. The sensitivity and response time of the sensors, without any catalyst on the surface, to 2% hydrogen at temperatures between 25 and 80°C were measured. Sensitivity greater than 50%, response time <220s, and power consumption <10nW at room temperature were demonstrated.
Double-gated field emitter array with carbon nanotubes grown by chemical vapor deposition
Authors: Choi Young Chul , Jeong Kwang Seok , Han In Taek , Kim Ha Jin , Jin Yong Wan , Kim Jong Min , Lee Byong Gon , Park Jong Hwan , Choe Deok Hyoen
Published: June 2006

We fabricated 4.75in. diagonal field emitter arrays with a double-gated structure in which the carbon nanotubes were synthesized by chemical vapor deposition using CO and H2 as feed gases. The nanotubes grown directly inside gate holes were used as an emitter. The diameter of the gate hole opening was as small as 4μm, accompanied with a large number of gate holes in a pixel. The electron beam spreading was minimized by employing a focus electrode. It was found that neither anode voltage nor focus electrode voltage had a strong influence on the anode current. The pixel-to-pixel uniformity of the fabricated structure was measured to be about 91%. Considering the limitation of the structure that has only a vertical resistive layer, it can be said that the fabricated field emitter shows quite a good uniformity.
Highly directional acoustic wave radiation based on asymmetrical two-dimensional phononic crystal resonant cavity
Authors: Ke Manzhu , Liu Zhengyou , Pang Pei , Wang Wengang , Cheng Zhigang , Shi Jing , Zhao Xingzhong , Wen Weijia
Published: June 2006

The radiation properties of an asymmetrical two-dimensional phononic crystal resonant cavity with a point source inside are investigated experimentally. The resonant cavity is formed by two separated phononic crystals of different thickness, both of which consist of the same square array of steel rods in water. We observe highly directional acoustic wave radiation when a point acoustic source is put inside the cavity. The radiation field has a half-power beam width less than 6°. This design may serve as a highly directional acoustic source in applications.
Temporal dynamics of rabbit haemorrhagic disease virus infection in a low-density population of wild rabbits (Oryctolagus cuniculus) in New Zealand
Authors: Henning J. , Pfeiffer D. U. , Davies P. R. , Meers J. , Morris R. S.
Published: June 2006

A longitudinal capture–mark–recapture study was conducted to determine the temporal dynamics of rabbit haemorrhagic disease (RHD) in a European rabbit (Oryctolagus cuniculus) population of low to moderate density on sand-hill country in the lower North Island of New Zealand. A combination of sampling (trapping and radio-tracking) and diagnostic (cELISA, PCR and isotype ELISA) methods was employed to obtain data weekly from May 1998 until June 2001. Although rabbit haemorrhagic disease virus (RHDV) infection was detected in the study population in all 3 years, disease epidemics were evident only in the late summer or autumn months in 1999 and 2001. Overall, 20% of 385 samples obtained from adult animals older than 11 weeks were seropositive. An RHD outbreak in 1999 contributed to an estimated population decline of 26%. A second RHD epidemic in February 2001 was associated with a population decline of 52% over the subsequent month. Following the outbreaks, the seroprevalence in adult survivors was between 40% and 50%. During 2000, no deaths from RHDV were confirmed and mortalities were predominantly attributed to predation. Influx of seronegative immigrants was greatest in the 1999 and 2001 breeding seasons, and preceded the RHD epidemics in those years. Our data suggest that RHD epidemics require the population immunity level to fall below a threshold where propagation of infection can be maintained through the population.
Home-range size and selection of natal den and diurnal shelter sites by urban red foxes (Vulpes vulpes) in Melbourne
Authors: Marks Clive A. , Bloomfield Tim E.
Published: June 2006

Selection of natal dens and diurnal shelters by red foxes (Vulpes vulpes) was investigated within the metropolitan area of Melbourne. Of 72 natal dens, 61% were in residential, public park, school or industrial lands. Most dens were beneath buildings (44.4%) or in earth banks (30.6%). The habitat categories in which dens were sited did not differ significantly from those described for London. Dens were more common beneath weatherboard buildings and were associated with properties that did not contain domestic dogs (Canis lupus familiaris). Diurnal shelter positions for 20 radio-collared foxes were obtained, and home-range data collected for 11 foxes. Estimated areas of adult home-range, for 100% minimum convex polygons (MCPs), varied between 11.5 and 45.8 ha, with from two to five diurnal shelter sites used in each home-range. Foxes showed a consistent preference for diurnal shelters associated with exotic weed infestations over ornamental and native vegetation or built habitats. Within these categories a diversity of substrates were used, including buildings, drains, graves, cypress trees, ornamental rockeries and garden beds. A preference for exotic weed infestations is an identifiable resource requirement for foxes in Melbourne and its removal may assist in reducing the abundance of urban foxes.
Diet and feeding selectivity of common wombats
Authors: Evans Murray C. , Macgregor Cate , Jarman Peter J.
Published: June 2006

The seasonal diets and feeding selectivity of common wombats (Vombatus ursinus) in mountainous eucalypt forest, eucalypt woodland and pasture were determined using faecal analysis. Grass species contributed the largest proportion (95%) of epidermal fragment area in faecal pellets, with at least 20 species being eaten. The most abundant grasses in pellets in all seasons were the tough, wiry snow grasses (Poa sieberiana and P. labillardieri), with Microlaena stipoides comprising a substantial proportion of the diet in summer and autumn. Grass leaf was the most abundant plant part in pellets (81%), with grass stem and grass sheath comprising 11%. The seasonal proportion of grass seedhead in pellets varied from just traces during autumn and winter to a substantial component of the diet during summer (21% of epidermal fragments in pellets). Forbs comprised less than 1% of pellet material, and tree or shrub species were not detected in the diet. Feeding selectivity (and hence dietary niche breadth) varied seasonally; wombats become less selective in their feeding as plant diversity and abundance decreased. Positive selection was shown for monocots and negative selection for forbs. Grass species were eaten in broadly similar proportions to their abundances in the field, but with moderate to strong selection or rejection of a few species.
Breakup of a homeobox cluster after genome duplication in teleosts
Authors: Mulley John F. , Chiu Chi-hua , Holland Peter W. H.
Published: June 2006

Several families of homeobox genes are arranged in genomic clusters in metazoan genomes, including the Hox, ParaHox, NK, Rhox, and Iroquois gene clusters. The selective pressures responsible for maintenance of these gene clusters are poorly understood. The ParaHox gene cluster is evolutionarily conserved between amphioxus and human but is fragmented in teleost fishes. We show that two basal ray-finned fish,
Polypterus
and
Amia
, each possess an intact ParaHox cluster; this implies that the selective pressure maintaining clustering was lost after whole-genome duplication in teleosts. Cluster breakup is because of gene loss, not transposition or inversion, and the total number of ParaHox genes is the same in teleosts, human, mouse, and frog. We propose that this homeobox gene cluster is held together in chordates by the existence of interdigitated control regions that could be separated after locus duplication in the teleost fish.
Modulating role of estradiol on arginase II expression in hyperlipidemic rabbits as an atheroprotective mechanism
Authors: Hayashi Toshio , Esaki Teiji , Sumi Daigo , Mukherjee Tapan , Iguchi Akihisa , Chaudhuri Gautam
Published: June 2006

We evaluated the effects of a 0.5% cholesterol-enriched diet (HCD) on nitric-oxide synthase (NOS) and arginase expression and the modulating role of 17β-estradiol (E
2
) on this phenomenon. Thirty oopherectomized rabbits were divided into three groups and treated for 15 weeks. Group I received normal chow; group II, HCD; and group III, HCD plus E
2
pellets. Animals in group II showed an increase in plasma lipids, and they demonstrated atheromatous lesions as well as expression of arginase I and II accompanied by a significant number of BrdU-positive cells in endothelial cells and intimal muscle cells, suggestive of an increase in cellular proliferation. There was significant expression of inducible NOS and increased staining of nitrotyrosine-positive areas. These were not observed in group I animals. In both groups, E
2
levels were low. In group III animals, E
2
supplementation led to a decrease in atheromatous lesions and BrdU-positive cells and reduced expression of both inducible NOS and arginase I and II accompanied by a decrease in nitrotyrosine staining. E
2
levels were increased. Our results suggest that E
2
was responsible for these effects, despite the animals being hyperlipidemic, similar to those in group II. Because arginase is responsible for cell proliferation by converting
l
-arginine to polyamines, our results indicate that expression of arginase may play an important role in cellular proliferation in atherosclerosis, and inhibition of arginase expression by E
2
may be another potential mechanism in attenuating atherogenesis.
Death-receptor activation halts clathrin-dependent endocytosis
Authors: Austin Cary D. , Lawrence David A. , Peden Andrew A. , Varfolomeev Eugene E. , Totpal Klara , De Mazière Ann M. , Klumperman Judith , Arnott David , Pham Victoria , Scheller Richard H. , Ashkenazi Avi
Published: June 2006

Endocytosis is crucial for various aspects of cell homeostasis. Here, we show that proapoptotic death receptors (DRs) trigger selective destruction of the clathrin-dependent endocytosis machinery. DR stimulation induced rapid, caspase-mediated cleavage of key clathrin-pathway components, halting cellular uptake of the classic cargo protein transferrin. DR-proximal initiator caspases cleaved the clathrin adaptor subunit AP2α between functionally distinct domains, whereas effector caspases processed clathrin’s heavy chain. DR5 underwent ligand-induced, clathrin-mediated endocytosis, suggesting that internalization of DR signaling complexes facilitates clathrin-pathway targeting by caspases. An endocytosis-blocking, temperature-sensitive
dynamin-1
mutant attenuated DR internalization, enhanced caspase stimulation downstream of DRs, and increased apoptosis. Thus, DR-triggered caspase activity disrupts clathrin-dependent endocytosis, leading to amplification of programmed cell death.
Turbulent flow properties of large-scale vortex systems
Authors: Bernard P. S.
Published: June 2006

Large-scale computations of dynamically interacting vortex tubes forming filaments are performed with a view toward investigating their relationship to turbulent fluid flow. It is shown that the statistical properties of the tubes are consistent with commonly accepted observations about turbulence such as the Kolmogorov inertial range spectrum and lognormality of the vorticity distribution. A loop-removal algorithm is demonstrated to reduce the nominally exponential growth rate in the number of tubes to linear growth without apparent harm to the underlying physics. In this form, a vortex tube method may become a practical means for simulating high Reynolds number turbulent flows.
The political contradictions of Algerian economic reforms
Authors: Addi Lahouari
Published: June 2006

From the outset, independent Algeria's political economy was marked by a paradox, for which it is still, today, paying the price. In 1962, the State, which is essentially public, was privatised, while commercial activities, which are essentially private, were made public. That was the time when revolutionary elites in the Third World thought that faith alone was enough to develop the country, using the State but without setting up the institutions guaranteeing free expression for the social groups organised as parties, trade unions, vested interests in order to participate in the political process. In the Boumedienne-Abdeslam period (1965-1978), the economic sector of the State was expected to absorb all commercial activities, from the large-scale steel industry down to the small local bakery, preventing the different social groups from enjoying any economic autonomy. Nor were they expected to make any claims on the political order. The State had set itself the task of satisfying all social needs through the so-called public sector whose vocation was not to make any profits, but to serve the public and, as a priority, the most destitute among the population.

Cet article traite des réformes économiques en Algérie, à l'ordre du jour depuis les années 1980, non encore réalisées malgré les discours des gouvernements successifs. Visant formellement à opérer la transition de l'économie administrée vers l'économie de marché, ces réformes se heurtent à la nature autoritaire du régime dans lequel des clans puissants utilisent les institutions de l'Etat pour s'enrichir. Ils s'opposent à la concurrence et à la mise en place d'un capitalisme manufacturier productif, préférant la spéculation et le commerce comme seuls modes d'accumulation.

Par ailleurs, l'Etat refuse toujours de se débarrasser du secteur économique public déficitaire, craignant de faire exploser les chiffres déjà élevés du chômage. Il préfère continuer à financer les déficits des entreprises sous sa tutelle et à distribuer des salaires vidés de leur pouvoir d'achat par des dévaluations massives, tout en interdisant la liberté syndicale pour empêcher les travailleurs de s'opposer aux effets de ces dévaluations.

L'embellie financière, suite à l'augmentation spectaculaire des prix mondiaux des hydrocarbures à partir de 1999, n'est pas mise à profit pour augmenter les capacités productives du marché national. Un programme de reconstruction a été lancé, certes nécessaire, mais rien n'a été prévu pour encourager la production. Au lieu d'exploiter les formidables ressources financières pour modifier le caractère rentier de l'économie, le gouvernement a opté pour une politique distributive qui allège momentanément les effets du chômage et qui permet à une couche privilégiée de s'approprier une part importante de la rente énergétique.
Tobacco images and texts in Norwegian magazines and newspapers
Authors: Løchen Maja-Lisa , Torhild Gram Inger , Skattebo Sigrid , Kolstrup Nils
Published: June 2006

Background: Print media may influence smoking behaviour through tobacco advertisements and editorial use of tobacco pictures and texts. In Norway tobacco advertising has been banned for many years. The authors studied the coverage of tobacco promotion and tobacco and health in some general Norwegian magazines and newspapers. The findings were related to the publications' policy as stated by their editors. Methods: During three months in 1998—99 all pictures of tobacco and smoking situations were registered, plus the coverage on health aspects of tobacco in all consecutive issues of 7 newspapers and 19 magazines. The editors were asked about their attitudes regarding indirect tobacco advertisement and editorial use of people smoking. Results: All editors for men's magazines and the majority of newspaper editors had no restrictions on displaying both indirect tobacco advertisements and images of people smoking. In total, 610 texts or pictures on tobacco were found in the 624 issues of magazines and newspapers. Only 26 items were indirect tobacco advertisements. Items promoting smoking were more common than coverage of tobacco and health (71% vs 29%), and occurred most frequently in men's magazines (2.1 per issue) and least frequently in local newspapers (0.3 per issue). The proportion of tobacco and health coverage compared with the total tobacco coverage was significantly lower in men's than in family magazines and local newspapers. Conclusion: Editors should be encouraged to increase the coverage of tobacco and health in print media. This may be an important factor in helping their readers to give up or not to take up smoking.
Binding of a Gating Modifier Toxin Induces Intersubunit Cooperativity Early in the Shaker K Channel's Activation Pathway
Authors: Sack Jon T. , Aldrich Richard W.
Published: June 2006

Potassium currents from voltage-gated Shaker K channels activate with a sigmoid rise. The degree of sigmoidicity in channel opening kinetics confirms that each subunit of the homotetrameric Shaker channel undergoes more than one conformational change before the channel opens. We have examined effects of two externally applied gating modifiers that reduce the sigmoidicity of channel opening. A toxin from gastropod mucus, 6-bromo-2-mercaptotryptamine (BrMT), and divalent zinc are both found to slow the same conformational changes early in Shaker's activation pathway. Sigmoidicity measurements suggest that zinc slows a conformational change independently in each channel subunit. Analysis of activation in BrMT reveals cooperativity among subunits during these same early steps. A lack of competition with either agitoxin or tetraethylammonium indicates that BrMT binds channel subunits outside of the external pore region in an allosterically cooperative fashion. Simulations including negatively cooperative BrMT binding account for its ability to induce gating cooperativity during activation. We conclude that cooperativity among K channel subunits can be greatly altered by experimental conditions.
Molecular and Functional Differences between Heart mKv1.7 Channel Isoforms
Authors: Finol-Urdaneta Rocio K. , Strüver Nina , Terlau Heinrich
Published: June 2006

Ion channels are membrane-spanning proteins that allow ions to permeate at high rates. The kinetic characteristics of the channels present in a cell determine the cell signaling profile and therefore cell function in many different physiological processes. We found that Kv1.7 channels from mouse heart muscle have two putative translation initiation start sites that generate two channel isoforms with different functional characteristics, mKv1.7L (489 aa) and a shorter mKv1.7S (457 aa). The electrophysiological analysis of mKv1.7L and mKv1.7S channels revealed that the two channel isoforms have different inactivation kinetics. The channel resulting from the longer protein (L) inactivates faster than the shorter channels (S). Our data supports the hypothesis that mKv1.7L channels inactivate predominantly due to an N-type related mechanism, which is impaired in the mKv1.7S form. Furthermore, only the longer version mKv1.7L is regulated by the cell redox state, whereas the shorter form mKv1.7S is not. Thus, expression starting at each translation initiation site results in significant functional divergence. Our data suggest that the redox modulation of mKv1.7L may occur through a site in the cytoplasmic N-terminal domain that seems to encompass a metal coordination motif resembling those found in many redox-sensitive proteins. The mRNA expression profile and redox modulation of mKv1.7 kinetics identify these channels as molecular entities of potential importance in cellular redox-stress states such as hypoxia.
Palytoxin-induced Effects on Partial Reactions of the Na,K-ATPase
Authors: Harmel Nadine , Apell Hans-Jürgen
Published: June 2006

The interaction of palytoxin with the Na,K-ATPase was studied by the electrochromic styryl dye RH421, which monitors the amount of ions in the membrane domain of the pump. The toxin affected the pump function in the state P-E2, independently of the type of phosphorylation (ATP or inorganic phosphate). The palytoxin-induced modification of the protein consisted of two steps: toxin binding and a subsequent conformational change into a transmembrane ion channel. At 20°C, the rate-limiting reaction had a forward rate constant of 105 M−1s−1 and a backward rate constant of about 10−3 s−1. In the palytoxin-modified state, the binding affinity for Na+ and H+ was increased and reached values between those obtained in the E1 and P-E2 conformation under physiological conditions. Even under saturating palytoxin concentrations, the ATPase activity was not completely inhibited. In the Na/K mode, ∼50% of the enzyme remained active in the average, and in the Na-only mode 25%. The experimental findings indicate that an additional exit from the inhibited state exists. An obvious reaction pathway is a slow dephosphorylation of the palytoxin-inhibited state with a time constant of ∼100 s. Analysis of the effect of blockers of the extracellular and cytoplasmic access channels, TPA+ and Br2-Titu3+, respectively, showed that both access channels are part of the ion pathway in the palytoxin-modified protein. All experiments can be explained by an extension of the Post-Albers cycle, in which three additional states were added that branch off in the P-E2 state and lead to states in which the open-channel conformation is introduced and returns into the pump cycle in the occluded E2 state. The previously suggested molecular model for the channel state of the Na,K-ATPase as a conformation in which both gates between binding sites and aqueous phases are simultaneously in their open state is supported by this study.
Ataxin-2 Interacts with the DEAD/H-Box RNA Helicase DDX6 and Interferes with P-Bodies and Stress Granules
Authors: Nonhoff Ute , Ralser Markus , Welzel Franziska , Piccini Ilaria , Balzereit Daniela , Yaspo Marie-Laure , Lehrach Hans , Krobitsch Sylvia
Published: June 2006

Tight control of translation is fundamental for eukaryotic cells, and deregulation of proteins implicated contributes to numerous human diseases. The neurodegenerative disorder spinocerebellar ataxia type 2 is caused by a trinucleotide expansion in the SCA2 gene encoding a lengthened polyglutamine stretch in the gene product ataxin-2, which seems to be implicated in cellular RNA-processing pathways and translational regulation. Here, we substantiate a function of ataxin-2 in such pathways by demonstrating that ataxin-2 interacts with the DEAD/H-box RNA helicase DDX6, a component of P-bodies and stress granules, representing cellular structures of mRNA triage. We discovered that altered ataxin-2 levels interfere with the assembly of stress granules and cellular P-body structures. Moreover, ataxin-2 regulates the intracellular concentration of its interaction partner, the poly(A)-binding protein, another stress granule component and a key factor for translational control. Thus, our data imply that the cellular ataxin-2 concentration is important for the assembly of stress granules and P-bodies, which are main compartments for regulating and controlling mRNA degradation, stability, and translation.
Flood hazard and management: a UK perspective
Authors: Wheater Howard S
Published: June 2006

This paper discusses whether flood hazard in the UK is increasing and considers issues of flood risk management. Urban development is known to increase fluvial flood frequency, hence design measures are routinely implemented to minimize the impact. Studies suggest that historical effects, while potentially large at small scale, are not significant for large river basins. Storm water flooding within the urban environment is an area where flood hazard is inadequately defined; new methods are needed to assess and manage flood risk. Development on flood plains has led to major capital expenditure on flood protection, but government is attempting to strengthen the planning role of the environmental regulator to prevent this. Rural land use management has intensified significantly over the past 30 years, leading to concerns that flood risk has increased, at least at local scale; the implications for catchment-scale flooding are unclear. New research is addressing this issue, and more broadly, the role of land management in reducing flood risk. Climate change impacts on flooding and current guidelines for UK practice are reviewed. Large uncertainties remain, not least for the occurrence of extreme precipitation, but precautionary guidance is in place. Finally, current levels of flood protection are discussed. Reassessment of flood hazard has led to targets for increased flood protection, but despite important developments to communicate flood risk to the public, much remains to be done to increase public awareness of flood hazard.