bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of postcondensation exchange on the isotopic composition of water in the atmosphere
Authors: Field Robert D. , Jones Dylan B. A. , Brown Derek P.
Published: December 2010

We conducted experiments with an atmospheric general circulation model to determine the effects of non‐Rayleigh, postcondensation exchange (PCE) on the isotopic composition of water in the atmosphere. PCE was found to universally deplete vapor of heavy isotopes but had differential effects on the isotopic composition of precipitation. At low latitudes, local PCE with fresh vapor at the surface enriches precipitation in heavy isotopes, particularly during light rainfall. When rainfall is heavy, PCE tends to deplete vapor and precipitation of heavy isotopes via atmospheric moisture recycling, supporting recent interpretations of vapor isotope measurements from satellites, particularly over the Asian Monsoon region. In the extratropics, PCE causes local enrichment of precipitation, which is often entirely offset by upstream PCE depletion of the source vapor, resulting in a net depletion in local precipitation. The transition from net enrichment to net depletion is controlled by the transition from rain to snow‐dominated precipitation. Surprisingly, this transition was also found to influence the temperature effect. In regions with a strong seasonal mix of rain and snow, such as Europe, the temperature effect appears to be controlled by PCE rather than Rayleigh depletion.
Effects of decadal deposition of nitrogen and sulfur, and increased temperature, on methane emissions from a boreal peatland
Authors: Eriksson Tobias , Öquist Mats G. , Nilsson Mats B.
Published: December 2010

Boreal peatlands represent a significant source of methane to the atmosphere. Pollutants and climate changes resulting from human activity are likely to affect the processes controlling methane emissions from these systems. This study investigated the effects of decadal deposition of nitrogen and sulfate, and increased air temperature, on methane emissions from a northern Swedish peatland during the snow‐free seasons of 2005 and 2006, the latter being exceptionally dry. The experimental setup involved a full factorial design at two levels with greenhouse cover (present or absent), nitrogen deposition (2 or 30 kg N ha−1 a−1), and sulfate deposition (3 or 20 kg S ha−1 a−1) as experimental factors. Methane emission rates were measured using static chambers after 10–11 years of experimental manipulations. Emissions were significantly reduced by the greenhouse treatment in 2005, by 30% on average, but not in 2006. The reduction in methane emissions in response to the greenhouse treatment were counteracted by nitrogen deposition; with high nitrogen deposition the effect of the greenhouse cover was low and nonsignificant. High nitrogen deposition increased methane emissions at ambient sulfate levels, probably due to sedge cover increasing from 37 to 65%, but the combination of high nitrogen deposition and high sulfate deposition did not affect methane emissions. Effects of increased nitrogen on methane emission have previously in short‐term manipulations (<6 years) been ranging from slightly negative to slightly positive. The substantial positive effects observed in this study emphasize the need for long‐term manipulations to obtain valid results under natural conditions.
Environmental distribution and abundance of the facultative methanotroph Methylocella
Authors: Rahman Md Tanvir , Crombie Andrew , Chen Yin , Stralis-Pavese Nancy , Bodrossy Levente , Meir Patrick , McNamara Niall P , Murrell J Colin
Published: December 2010

Methylocella spp. are facultative methanotrophs, which are able to grow not only on methane but also on multicarbon substrates such as acetate, pyruvate or malate. Methylocella spp. were previously thought to be restricted to acidic soils such as peatlands, in which they may have a key role in methane oxidation. There is little information on the abundance and distribution of Methylocella spp. in the environment. New primers were designed, and a real-time quantitative PCR method was developed and validated targeting Methylocella mmoX (encoding the α-subunit of the soluble methane monooxygenase) that allowed the quantification of Methylocella spp. in environmental samples. We also developed and validated specific PCR assays, which target 16S rRNA genes of known Methylocella spp. These were used to investigate the distribution of Methylocella spp. in a variety of environmental samples. It was revealed that Methylocella species are widely distributed in nature and not restricted to acidic environments.
Phosphorus supply drives rapid turnover of membrane phospholipids in the diatom Thalassiosira pseudonana
Authors: Martin Patrick , Van Mooy Benjamin A S , Heithoff Abigail , Dyhrman Sonya T
Published: December 2010

In low-phosphorus (P) marine systems, phytoplankton replace membrane phospholipids with non-phosphorus lipids, but it is not known how rapidly this substitution occurs. Here, when cells of the model diatom Thalassiosira pseudonana were transferred from P-replete medium to P-free medium, the phospholipid content of the cells rapidly declined within 48 h from 45±0.9 to 21±4.5% of the total membrane lipids; the difference was made up by non-phosphorus lipids. Conversely, when P-limited T. pseudonana were resupplied with P, cells reduced the percentage of their total membrane lipids contributed by a non-phosphorus lipid from 43±1.5 to 7.3±0.9% within 24 h, whereas the contribution by phospholipids rose from 2.2±0.1 to 44±3%. This dynamic phospholipid reservoir contained sufficient P to synthesize multiple haploid genomes, suggesting that phospholipid turnover could be an important P source for cells. Field observations of phytoplankton lipid content may thus reflect short-term changes in P supply and cellular physiology, rather than simply long-term adjustment to the environment.
Endolithic chlorophyll d-containing phototrophs
Authors: Behrendt Lars , Larkum Anthony W D , Norman Anders , Qvortrup Klaus , Chen Min , Ralph Peter , Sørensen Søren J , Trampe Erik , Kühl Michael
Published: December 2010

Cyanobacteria in the genus Acaryochloris are the only known oxyphototrophs that have exchanged chlorophyll a (Chl a) with Chl d as their primary photopigment, facilitating oxygenic photosynthesis with near infrared (NIR) light. Yet their ecology and natural habitats are largely unknown. We used hyperspectral and variable chlorophyll fluorescence imaging, scanning electron microscopy, photopigment analysis and DNA sequencing to show that Acaryochloris-like cyanobacteria thrive underneath crustose coralline algae in a widespread endolithic habitat on coral reefs. This finding suggests an important role of Chl d-containing cyanobacteria in a range of hitherto unexplored endolithic habitats, where NIR light-driven oxygenic photosynthesis may be significant.
Collective cell guidance by cooperative intercellular forces
Authors: Tambe Dhananjay , Hardin Charles , Fredberg Jeffrey , Trepat Xavier
Published: December 2010

Cells comprising a tissue migrate as part of a collective. In order to coordinate collective multi- cellular migration, each constituent cell integrates local information including chemical signals and mechanical stresses. The boundary between a constituent cell and its immediate neighbors comprises cell-cell junctions and cryptic lamellipodia, but the state of local mechanical stress exerted at that boundary has not been accessible experimentally. As such it is not clear how collective mechanical processes could be coordinated over length scales spanning large multi-cellular assemblies. We report here maps of the stresses exerted within and between cells comprising a monolayer. Within the cell sheet there arise unanticipated fluctuations of mechanical stress that are severe, emerge spontaneously, and ripple across the monolayer. These fluctuations define a rugged stress landscape that becomes increasingly heterogeneous, sluggish, and cooperative with increasing system density. Within that persistently rugged stress landscape, local cellular migrations are found to migrate along local orientations of maximal principal stress. Migrations of both endothelial and epithelial monolayers conform to this behavior, as do breast cancer cell lines before but not after the epithelial-mesenchymal transition. In these diverse cell types, our data indicate that collective migration is governed by a simple but unifying physiological principle: neighboring cells join forces to transmit appreciable intercellular normal stress across local cell-cell junctions, but migrate along orientations of minimal intercellular shear stress.
Gp130 Cytokines Exert Differential Patterns of Crosstalk in Adipocytes Both In Vitro and In Vivo
Authors: White Ursula A. , Stewart William C. , Stephens Jacqueline M.
Published: December 2010

Glycoprotein 130 (Gp130) cytokines are involved in the regulation of numerous biological processes, including hematopoiesis, immune response, inflammation, cardiovascular action, and neuronal survival. These cytokines share gp130 as a common signal transducer in their receptor complex and typically activate signal transducer and activator of transcription (STAT) 3. Studies have shown that several gp130 cytokines have differential effects on both adipogenesis and insulin‐stimulated glucose uptake. Yet, the complex interactions of these cytokines in adipose tissue have not been studied. Gp130 cytokines are differentially regulated in multiple tissues due to the presence of additional receptor components that are required for signaling, including the leukemia inhibitory factor receptor (LIFR). Previous studies from our laboratory highlighted the ability of specific gp130 cytokines to crosstalk in adipocytes that correlated with LIFR degradation. Crosstalk is defined as the ability of one cytokine to modulate the signaling of another cytokine. Our novel studies reveal that white adipose tissue is highly responsive to gp130 cytokines, and we provide the first evidence that these cytokines can exert inhibitory crosstalk in adipose tissue in vivo. Moreover, several gp130 cytokines that use the LIFR, including cardiotrophin‐1 (CT‐1), LIF, and human oncostatin M (hOSM), can alter the subsequent signaling of other family members in adipocytes both in vitro and in vivo. Our data also show that murine OSM and neuropoietin do not crosstalk in the same manner as other gp130 cytokines, which likely results from their inability to activate the LIFR. Overall, we have observed distinctive patterns of crosstalk signaling by gp130 cytokines in adipocytes in vitro and in vivo and demonstrate the crosstalk is not dependent on new protein synthesis or extracellular‐signal‐regulated kinase activation.
Accuracy of Maternal Recall of Gestational Weight Gain 4 to 12 Years After Delivery
Authors: McClure Candace K. , Bodnar Lisa M. , Ness Roberta , Catov Janet M.
Published: December 2010

There is growing interest in the relationship between gestational weight gain (GWG) and long‐term maternal and child outcomes, yet little is known about the accuracy of long‐term maternal recall of GWG. Our objective was to assess the accuracy of maternal recall of GWG at 4–12 years postpartum (mean, 8 years) compared with medical‐record documented GWG, and compare recalled GWG to documented GWG with respect to their associations with adverse pregnancy outcomes including small for gestational age (SGA) birth, preterm birth, cesarean delivery, and postpartum weight retention (PPWR) (n = 503). Adequacy of recalled and documented GWG was assessed according to the 2009 Institute of Medicine (IOM) guidelines. We observed moderate agreement between documented and maternal self‐reported GWG as continuous variables (r = 0.63, P < 0.01). When recalled GWG was used to categorize women, 45, 53, and 20% of women with inadequate, adequate, and excessive documented GWG were misclassified, respectively. When comparing models fitted with documented or recalled GWG, there were no meaningful differences in associations between inadequate GWG and SGA birth (odds ratio 2.2 (95% confidence interval: 1.3, 3.7) vs. 2.1 (1.2, 3.8), respectively) or excessive GWG and PPWR (2.5 (1.6, 3.9) vs. 2.5 (1.5, 4.0), respectively). However, the use of recalled GWG attenuated associations between inadequate GWG and PPWR (documented: 0.5 (0.3, 0.9) vs. recalled GWG: 1.3 (0.7, 2.3)) and excessive GWG and preterm birth (documented: 2.5 (1.4, 4.5) vs. recalled GWG: 1.5 (0.9, 2.7)). Our data suggest a varying degree of bias when using recalled GWG to study selected adverse outcomes.
Investigating Children's Physical Activity and Sedentary Behavior Using Ecological Momentary Assessment With Mobile Phones
Authors: Dunton Genevieve F. , Liao Yue , Intille Stephen S. , Spruijt‐Metz Donna , Pentz Maryann
Published: December 2010

The risk of obesity during childhood can be significantly reduced through increased physical activity and decreased sedentary behavior. Recent technological advances have created opportunities for the real‐time measurement of these behaviors. Mobile phones are ubiquitous and easy to use, and thus have the capacity to collect data from large numbers of people. The present study tested the feasibility, acceptability, and validity of an electronic Ecological Momentary Assessment (EMA) protocol using electronic surveys administered on the display screen of mobile phones to assess children's physical activity and sedentary behaviors. A total of 121 children (ages 9–13, 51% male, 38% at risk for overweight/overweight) participated in EMA monitoring from Friday afternoon to Monday evening during children's nonschool time, with 3–7 surveys/day. Items assessed current activity (e.g., watching TV/movies, playing video games, active play/sports/exercising). Children simultaneously wore an Actigraph GT2M accelerometer. EMA survey responses were time‐matched to total step counts and minutes of moderate‐to‐vigorous physical activity (MVPA) occurring in the 30 min before each EMA survey prompt. No significant differences between answered and unanswered EMA surveys were found for total steps or MVPA. Step counts and the likelihood of 5+ min of MVPA were significantly higher during EMA‐reported physical activity (active play/sports/exercising) vs. sedentary behaviors (reading/computer/homework, watching TV/movies, playing video games, riding in a car) (P < 0.001). Findings generally support the acceptability and validity of a 4‐day EMA protocol using mobile phones to measure physical activity and sedentary behavior in children during leisure time.
Exploring a role for heteromerization in GPCR signalling specificity
Authors: Rozenfeld Raphael , Devi Lakshmi A.
Published: December 2010

The critical involvement of GPCRs (G-protein-coupled receptors) in nearly all physiological processes, and the presence of these receptors at the interface between the extracellular and the intracellular milieu, has positioned these receptors as pivotal therapeutic targets. Although a large number of drugs targeting GPCRs are currently available, significant efforts have been directed towards understanding receptor properties, with the goal of identifying and designing improved receptor ligands. Recent advances in GPCR pharmacology have demonstrated that different ligands binding to the same receptor can activate discrete sets of downstream effectors, a phenomenon known as ‘ligand-directed signal specificity’, which is currently being explored for drug development due to its potential therapeutic advantage. Emerging studies suggest that GPCR responses can also be modulated by contextual factors, such as interactions with other GPCRs. Association between different GPCR types leads to the formation of complexes, or GPCR heteromers, with distinct and unique signalling properties. Some of these heteromers activate discrete sets of signalling effectors upon activation by the same ligand, a phenomenon termed ‘heteromer-directed signalling specificity’. This has been shown to be involved in the physiological role of receptors and, in some cases, in disease-specific dysregulation of a receptor effect. Hence targeting GPCR heteromers constitutes an emerging strategy to select receptor-specific responses and is likely to be useful in achieving specific beneficial therapeutic effects.
The electronic and magnetic properties of (Mn,N)-codoped ZnO from first principles
Authors: Zhao L. , Lu P. F. , Yu Z. Y. , Guo X. T. , Shen Y. , Ye H. , Yuan G. F. , Zhang L.
Published: December 2010

The electronic and magnetic properties of (Mn,N)-codoped ZnO are studied within the framework of the density functional theory, by using the Perdew–Burke–Ernzerhof form of generalized gradient approximation. Five geometrical configurations of Mn doped ZnO are investigated and antiferromagnetic (AFM) properties of Mn doped ZnO are demonstrated. Furthermore, by investigating 13 geometrical configurations, for (Mn,N)-codoped ZnO, the ground state is changed from no-metallic AFM to half-metallic ferromagnetic, which is due to the strong hybridization between N 2p and Mn 3d states. In addition, the most stable configurations are found to be –O–Mn–N–Mn–O–.
Inverse spin-Hall effect in palladium at room temperature
Authors: Ando K. , Saitoh E.
Published: December 2010

The inverse spin-Hall effect, conversion of a spin current into electromotive force, has been investigated in a simple Ni81Fe19/Pd film using the spin pumping. In the Ni81Fe19/Pd film, a spin current generated by the spin pumping is converted into an electromotive force using the inverse spin-Hall effect in the Pd layer. From the magnitude of the electromotive force, we estimated the spin-Hall angle for Pd as 0.01. This large spin-Hall angle for Pd is consistent with the prediction from the Gilbert damping enhancement due to the spin pumping. This value will be a crucial piece of information for spintronics device engineering.
Temporary bond-debond process for manufacture of flexible electronics: Impact of adhesive and carrier properties on performance
Authors: Haq Jesmin , Ageno Scott , Raupp Gregory B. , Vogt Bryan D. , Loy Doug
Published: December 2010

Manufacturing of microelectronics on flexible substrates is challenged by difficulties in maintaining alignment and conformity of the substrate through deposition, patterning, and etch processes. To address these difficulties, a temporary bond-debond method has been developed for effective automated handling of flexible substrate systems during electronics fabrication. The flexible substrate is temporarily bonded to a rigid carrier, which provides structural support and suppresses bending during processing. The photolithographic alignment of the bonded system is strongly dependent upon the viscoelastic properties of the bonding adhesive. An additional challenge is to control the stress developed during processing; these stresses evolve predominately through thermomechanical property mismatches between the carrier and flexible substrate. To investigate the role of the thermomechanical properties of the carrier and adhesive, the stress, and subsequent bowing of bonded systems (flexible substrate-adhesive-carrier) is examined systematically using different carriers and adhesives. Excellent registration of the flexible circuitry fabricated on the bonded system with low stress can be achieved by using a viscoelastic adhesive with a low loss factor (tan δ) and a carrier with high modulus and coefficient of thermal expansion that is closely matched to the flexible substrate. This bond-debond process enables the high yield fabrication of flexible microelectronics on plastic substrates.
An integrated instrument for rapidly deforming living cells using rapid pressure pulses and simultaneously monitoring applied strain in near real time
Authors: Green M. E. , Goforth P. B. , Satin L. S. , Love B. J.
Published: December 2010

Because many types of living cells are sensitive to applied strain, different in vitro models have been designed to elucidate the cellular and subcellular processes that respond to mechanical deformation at both the cell and tissue level. Our focus was to improve upon an already established strain system to make it capable of independently monitoring the deflection and applied pressure delivered to specific wells of a commercially available, deformable multiwell culture plate. To accomplish this, we devised a custom frame that was capable of mounting deformable 6 or 24 well plates, a pressurization system that could load wells within the plates, and a camera-based imaging system which was capable of capturing strain responses at a sufficiently high frame rate. The system used a user defined program constructed in Labview® to trigger plate pressurization while simultaneously allowing the deflection of the silicone elastomeric plate bottoms to be imaged in near real time. With this system, up to six wells could be pulsed simultaneously using compressed air or nitrogen. Digital image capture allowed near-real time monitoring of applied strain, strain rate, and the cell loading profiles. Although our ultimate goal is to determine how different strain rates applied to neurons modulates their intrinsic biochemical cascades, the same platform technology could be readily applied to other systems. Combining commercially available, deformable multiwell plates with a simple instrument having the monitoring capabilities described here should permit near real time calculations of stretch-induced membrane strain in multiple wells in real time for a wide variety of applications, including high throughput drug screening.
Development of algebraic techniques for the atomic open-shell MBPT(3)
Authors: Juršėnas Rytis , Merkelis Gintaras
Published: December 2010

The atomic third-order open-shell many-body perturbation theory is developed. Special attention is paid to the generation and algebraic analysis of terms of the wave operator and the effective Hamiltonian as well. Making use of occupation-number representation and intermediate normalization, the third-order derivations are worked out by employing a computational software program that embodies the generalized Bloch equation. We prove that in the most general case, the terms of effective interaction operator on the proposed complete model space are generated by a maximum of eight types of the n–body (n ⩾ 2) parts of the wave operator. To compose the effective Hamiltonian matrix elements in an efficient way, the operators are written in irreducible tensor form. We present the reduction scheme which is applied throughout other effective operator approaches to many-body perturbation theories, such as the coupled-cluster approach.
Low-temperature processed Schottky-gated field-effect transistors based on amorphous gallium-indium-zinc-oxide thin films
Authors: Lorenz M. , Lajn A. , Frenzel H. , v. Wenckstern H. , Grundmann M. , Barquinha P. , Martins R. , Fortunato E.
Published: December 2010

We have investigated the electrical properties of metal-semiconductor field-effect transistors (MESFET) based on amorphous oxide semiconductor channels. All functional parts of the devices were sputter-deposited at room temperature. The influence on the electrical properties of a 150 °C annealing step of the gallium-indium-zinc-oxide channel is investigated. The MESFET technology offers a simple route for processing of the transistors with excellent electrical properties such as low subthreshold swing of 112 mV/decade, gate sweep voltages of 2.5 V, and channel mobilities up to 15 cm2/V s.
Numerical calculation of equilibria with poloidal-sonic flow and finite Larmor radius effects in large aspect-ratio tokamaks
Authors: Raburn D. , Fukuyama A.
Published: December 2010

A code has been developed for calculating magnetohydrodynamic equilibria with poloidal-sonic flow and finite Larmor radius effects in high-beta tokamaks using an inverse aspect-ratio expansion and a reduced two-fluid model. The Grad–Shafranov equations governing the first- and second-order poloidal fluxes can be expressed in terms of five free profiles of the first-order poloidal flux. Sample equilibria, illustrating behaviors such as the deviation of pressure contours from the flux surfaces, and the criteria for the presence of the “poloidal-sonic singularity” are presented.
High harmonic generation spectroscopy of hydrocarbons
Authors: Vozzi C. , Torres R. , Negro M. , Brugnera L. , Siegel T. , Altucci C. , Velotta R. , Frassetto F. , Poletto L. , Villoresi P. , De Silvestri S. , Stagira S. , Marangos J. P.
Published: December 2010

We have demonstrated the ability of few-cycle midinfrared intense laser pulses to produce extended harmonic spectra (≥45 eV) suitable for high harmonic spectroscopy in aligned hydrocarbons with ionization potentials in the range 9.07–11.52 eV. Modulations in the spectra measured with different alignment angles show signatures of the molecular structure. These results pave the way for the extension of high harmonic spectroscopy to complex biomolecules.
Large-eddy simulations of a turbulent Coanda jet on a circulation control airfoil
Authors: Nishino Takafumi , Hahn Seonghyeon , Shariff Karim
Published: December 2010

Large-eddy simulations are performed of a turbulent Coanda jet separating from a rounded trailing edge of a simplified circulation control airfoil model. The freestream Reynolds number based on the airfoil chord is 0.49×106, the jet Reynolds number based on the jet slot height is 4470, and the ratio of the peak jet velocity to the freestream velocity is 3.96. Three different grid resolutions are used to show that their effect is very small on the mean surface pressure distribution, which agrees very well with experiments, as well as on the mean velocity profiles over the Coanda surface. It is observed that the Coanda jet becomes fully turbulent just downstream of the jet exit, accompanied by asymmetric alternating vortex shedding behind a thin (but blunt) jet blade splitting the jet and the external flow. A number of “backward-tilted” hairpin vortices (i.e., the head of each hairpin being located upstream of the legs) are observed around the outer edge of the jet over the Coanda surface. These hairpins create strong upwash between the legs and weak downwash around them, contributing to turbulent mixing of the high-momentum jet below the hairpins and the low-momentum external flow above them. The probability density distribution of velocity fluctuations is shown to be highly asymmetric in this region, consistent with the observation that the hairpin vortices create strong upwash and weak downwash. Turbulent structures inside the jet, its spreading rate, and self-similarity are also discussed.
Fluid simulation of an electrostatic plasma sheath with two species of positive ions and charged nanoparticles
Authors: Foroutan G.
Published: December 2010

One-dimensional fluid simulations are used to study the dynamics of an electrostatic plasma sheath containing nanosized dust grains and two species of positive ions, i.e., He+ and Ar+. The impacts of the concentration of each species, the velocity at the sheath edge of the ions, and the bias voltage of the substrate, on the spatial distribution of the velocity and number density of the plasma particles, and the incident fluxes of the ions on the substrate, are investigated. The numerical results show that the sheath thickness increases with increasing σ, the density ratio of He+ ions to Ar+ ions at the sheath edge. For nanosized dust particles considered in this work, the dominant forces are the ion drag and the electric force and the effects of the neutral drag and gravity are negligible. Due to enhancement of the ion drag force and the electric force, the dust velocity increases and, consequently, the dust number density decreases as the concentration at the sheath edge of Ar+ ions is increased. For the same velocity and number density at the sheath edge, the number density of Ar+ ions near the wall is larger than that of He+ ions, but their incident fluxes are the same. The maximum in the dust number density increases with the velocity of Ar+ ions at the sheath edge, but it weakly changes with the Mach number of He+ ions, except for large values of σ. The position of the maximum dust number density initially decreases very quickly with increasing the velocity at the sheath edge of the ions from small values, but then at larger values it changes quite slowly. The differences in the sheath parameters for different values of σ disappear at some values of the velocity at the sheath edge of the ions and dust particles. The incident flux of the ions are independent of the bias voltage of the substrate, but their kinetic energy is equal to the bias potential.
Experimental burning changes the quality of fallen timber as habitat for vertebrate and invertebrate fauna: implications for fire management
Authors: Croft Peter , Reid Nick , Hunter John T.
Published: December 2010

Context Fallen timber is a key habitat feature in forests and woodlands for vertebrate and invertebrate fauna, and is either consumed or left partially burnt after the passage of fire. This impact on habitat quality assumes significance because increasing areas of land are subject to frequent hazard-reduction burning and wildfire in eastern Australia. Aims We test here whether partially burnt or charred fallen timber is employed as habitat to the same extent as unburnt fallen timber. Methods Vertebrate and invertebrate abundance beneath burnt and unburnt fence posts was monitored for 13 months in unburnt forest and forest burnt by a wildfire. Key results Both vertebrate and invertebrate fauna made significantly less use of charred refuges. In most taxa, twice as many animals occurred under unburnt as under burnt artificial timber refuges, ant nests being the exception. Fauna made greater use of experimental refuges in burnt forest. Key conclusions Partially burnt fallen-timber refuges, where the log surface is left charred, are inferior habitat for fauna. Habitat quality in burnt forest may be enhanced by introducing fallen timber. Implications The study highlights an ecological consequence of fire for habitat quality, whether through wildfire or hazard-reduction burning, which should be considered in fire management.
Saccharides enhance iron bioavailability to Southern Ocean phytoplankton
Authors: Hassler Christel S. , Schoemann Véronique , Nichols Carol Mancuso , Butler Edward C. V. , Boyd Philip W.
Published: December 2010

Iron limits primary productivity in vast regions of the ocean. Given that marine phytoplankton contribute up to 40% of global biological carbon fixation, it is important to understand what parameters control the availability of iron (iron bioavailability) to these organisms. Most studies on iron bioavailability have focused on the role of siderophores; however, eukaryotic phytoplankton do not produce or release siderophores. Here, we report on the pivotal role of saccharides—which may act like an organic ligand—in enhancing iron bioavailability to a Southern Ocean cultured diatom, a prymnesiophyte, as well as to natural populations of eukaryotic phytoplankton. Addition of a monosaccharide (>2 nM of glucuronic acid, GLU) to natural planktonic assemblages from both the polar front and subantarctic zones resulted in an increase in iron bioavailability for eukaryotic phytoplankton, relative to bacterioplankton. The enhanced iron bioavailability observed for several groups of eukaryotic phytoplankton (i.e., cultured and natural populations) using three saccharides, suggests it is a common phenomenon. Increased iron bioavailability resulted from the combination of saccharides forming highly bioavailable organic associations with iron and increasing iron solubility, mainly as colloidal iron. As saccharides are ubiquitous, present at nanomolar to micromolar concentrations, and produced by biota in surface waters, they also satisfy the prerequisites to be important constituents of the poorly defined “ligand soup,” known to weakly bind iron. Our findings point to an additional type of organic ligand, controlling iron bioavailability to eukaryotic phytoplankton—a key unknown in iron biogeochemistry.
The heritability of multiple male mating in a promiscuous mammal
Authors: McFarlane S. Eryn , Lane Jeffrey E. , Taylor Ryan W. , Gorrell Jamieson C. , Coltman David W. , Humphries Murray M. , Boutin Stan , McAdam Andrew G.
Published: December 2010

The tendency of females to mate with multiple males is often explained by direct and indirect benefits that could outweigh the many potential costs of multiple mating. However, behaviour can only evolve in response to costs and benefits if there is sufficient genetic variation on which selection can act. We followed 108 mating chases of 85 North American red squirrels (
Tamiasciurus hudsonicus
) during 4 years, to measure each female's degree of multiple male mating (MMM), and used an animal model analysis of our multi-generational pedigree to provide what we believe is the first estimate of the heritability of MMM in the wild. Female red squirrels were highly polyandrous, mating with an average of 7.0 ± 0.2 males on their day of oestrus. Although we found evidence for moderate levels of additive genetic variation (CV
A
= 5.1), environmental variation was very high (CV
E
= 32.3), which resulted in a very low heritability estimate (
h
2
< 0.01). So, while there is genetic variation in this trait, the large environmental variation suggests that any costs or benefits associated with differences among females in MMM are primarily owing to environmental and not genetic differences, which could constrain the evolutionary response to natural selection on this trait.
Re-orienting in space: do animals use global or local geometry strategies?
Authors: Kelly Debbie M. , Chiandetti Cinzia , Vallortigara Giorgio
Published: December 2010

Here we compare whether birds encode surface geometry using principal axes, medial axes or local geometry. Birds were trained to locate hidden food in two geometrically identical corners of a rectangular arena and subsequently tested in an L-shaped arena. The chicks showed a primary local geometry strategy, and a secondary medial axes strategy, whereas the pigeons showed a medial axes strategy. Neither species showed behaviour supportive of the use of principal axes. This is, to our knowledge, the first study to directly examine these three current theories of geometric encoding.
On the range of the first two Dirichlet and Neumann eigenvalues of the Laplacian
Authors: Antunes Pedro R. S. , Henrot Antoine
Published: December 2010

In this paper, we study the set of points in the plane defined by {(
x
,
y
)=(
λ
1
(
Ω
),
λ
2
(
Ω
)), |
Ω
|=1}, where (
λ
1
(
Ω
),
λ
2
(
Ω
)) are either the first two eigenvalues of the Dirichlet–Laplacian, or the first two non-trivial eigenvalues of the Neumann–Laplacian. We consider the case of general open sets together with the case of convex open domains. We give some qualitative properties of these sets, show some pictures obtained through numerical computations and state several open problems.
Anti-predator defence drives parallel morphological evolution in flea beetles
Authors: Ge Deyan , Chesters Douglas , Gómez-Zurita Jesús , Zhang Lijie , Yang Xingke , Vogler Alfried P.
Published: December 2010

Complex morphological or functional traits are frequently considered evolutionarily unique and hence useful for taxonomic classification. Flea beetles (Alticinae) are characterized by an extraordinary jumping apparatus in the usually greatly expanded femur of their hind legs that separates them from the related Galerucinae. Here, we examine the evolution of this trait using phylogenetic analysis and a time-calibrated tree from mitochondrial (rrnLandcox1) and nuclear (small subunits and large subunits) genes, as well as morphometrics of femora using elliptic Fourier analysis. The phylogeny strongly supports multiple independent origins of the metafemoral spring and therefore rejects the monophyly of Alticinae, as defined by this trait. Geometric outline analysis of femora shows the great plasticity of this structure and its correlation with the type and diversity of the metafemoral springs. The recognition of convergence in jumping apparatus now resolves the long-standing difficulties of Galerucinae–Alticinae classification, and cautions against the value of trait complexity as a measure of taxonomic significance. The lineage also shows accelerated species diversification rates relative to other leaf beetles, which may be promoted by the same ecological factors that also favour the repeated evolution of jumping as an anti-predation mechanism.
Metapopulation dynamics of rabies and the efficacy of vaccination
Authors: Beyer Hawthorne L. , Hampson Katie , Lembo Tiziana , Cleaveland Sarah , Kaare Magai , Haydon Daniel T.
Published: December 2010

Spatial structure in a host population results in heterogeneity in transmission dynamics. We used a Bayesian framework to evaluate competing metapopulation models of rabies transmission among domestic dog populations in villages in Tanzania. A proximate indicator of disease, medical records of animal-bite injuries, is used to infer the occurrence (presence/absence) of suspected rabid dog cases in one month intervals. State-space models were used to explore the implications of different levels of reporting probability on model parameter estimates. We find evidence for a relatively high rate of infection of these populations from neighbouring districts or from other species distributed throughout the study area, rather than from adjacent wildlife protected areas, suggesting wildlife is unlikely to be implicated in the long-term persistence of rabies. Stochastic simulation of our highest ranked models in vaccinated and hypothetical unvaccinated populations indicated that pulsed vaccination campaigns occurring from 2002 to 2007 reduced rabies occurrence by 57.3 per cent in vaccinated villages in the 1 year following each pulse, and that a similar regional campaign would deliver an 80.9 per cent reduction in occurrence. This work demonstrates how a relatively coarse, proximate sentinel of rabies infection is useful for making inferences about spatial disease dynamics and the efficacy of control measures.
Population regulation of territorial species: both site dependence and interference mechanisms matter
Authors: Nevoux Marie , Gimenez Olivier , Arlt Debora , Nicoll Malcolm , Jones Carl , Norris Ken
Published: December 2010

Spatial patterns of site occupancy are commonly driven by habitat heterogeneity and are thought to shape population dynamics through a site-dependent regulatory mechanism. When examining this, however, most studies have only focused on a single vital rate (reproduction), and little is known about how space effectively contributes to the regulation of population dynamics. We investigated the underlying mechanisms driving density-dependent processes in vital rates in a Mauritius kestrel population where almost every individual was monitored. Different mechanisms acted on different vital rates, with breeding success regulated by site dependence (differential use of space) and juvenile survival by interference (density-dependent competition for resources). Although territorial species are frequently assumed to be regulated through site dependence, we show that interference was the key regulatory mechanism in this population. Our integrated approach demonstrates that the presence of spatial processes regarding one trait does not mean that they necessarily play an important role in regulating population growth, and demonstrates the complexity of the regulatory process.
Impaired conditional reasoning in alcoholics: a negative impact on social interactions and risky behaviors?
Authors: Kornreich Charles , Delle‐Vigne Dyna , Knittel Julian , Nerincx Aurore , Campanella Salvatore , Noel Xavier , Hanak Catherine , Verbanck Paul , Ermer Elsa
Published: December 2010

Aims To study the ‘social brain’ in alcoholics by investigating social contract reasoning, theory of mind and emotional intelligence.

Design A behavioral study comparing recently detoxified alcoholics with normal, healthy controls.

Setting Emotional intelligence and decoding of emotional non‐verbal cues have been shown to be impaired in alcoholics. This study explores whether these deficits extend to conditional reasoning about social contracts.

Participants Twenty‐five recently detoxified alcoholics (17 men and eight women) were compared with 25 normal controls (17 men and eight women) matched for sex, age and education level.

Measurements Wason selection task investigating conditional reasoning on three different rule types (social contract, precautionary and descriptive), revised Reading the Mind in the Eyes Test, Trait Emotional Intelligence Questionnaire (modified version) and additional control measures.

Findings Conditional reasoning was impaired in alcoholics. Performance on descriptive rules was not above chance. Reasoning performance was markedly better on social contract and precautionary rules, but this performance was still significantly lower than in controls. Several emotional intelligence measures were lower in alcoholics compared to controls, but these were not correlated with reasoning performance.

Conclusions Conditional reasoning, including reasoning about social contracts and emotional intelligence appear to be impaired in alcoholics. Impairment seems to be particularly severe on descriptive rules. Impairment in social contract reasoning might lead to misunderstandings and frustration in social interactions, and reasoning difficulties about precautionary rules might contribute to risky behaviors in this population.
Clinical experience with the treatment of hepatitis C infection in patients on opioid pharmacotherapy
Authors: Sasadeusz Joseph John , Dore Gregory , Kronborg Ian , Barton David , Yoshihara Motoko , Weltman Martin
Published: December 2010

Aims  To evaluate the efficacy, safety and adherence to hepatitis C (HCV) therapy in patients attending tertiary hepatitis clinics who are receiving opioid replacement therapy.

Design  A non‐randomized, open‐label study. Participants were treated with pegylated interferon alpha‐2a and weight‐based ribavirin for 24 weeks (genotype non–1, n = 31) or 48 weeks (genotype 1, n = 22).

Setting  Four tertiary hospital hepatitis clinics in Australia.

Participants  Fifty‐three patients with chronic HCV who were receiving opioid replacement therapy

Measurements  Patients were monitored for virological response, adverse events and adherence. They were also screened for psychiatric illness prior to and throughout the study utilizing two validated instruments: the Mini International Neuropsychiatric Interview (MINI) and Beck Depression Interview (BDI)‐II.

Findings  The overall sustained virological response (SVR) rate was 57% (71% genotype non‐1 versus 36% genotype 1), and was similar in active injectors (63%) and non‐injectors (53%). The psychological profile of patients based on validated instruments did not change on therapy. The pattern and frequency of adverse effects were comparable to non‐opioid replacement patients. Eighty‐five per cent of patients were adherent to therapy by 80/80/80 criteria and only two patients who had an end‐of‐treatment response relapsed, one of whom was not an active injector.

Conclusions  Patients on opioid replacement therapy, even if they continue to inject actively, can achieve comparable sustained virological response rates to other populations with pegylated interferon alpha‐2a and ribavirin therapy, suffer no excess rates of adverse effects or psychological complications and have good adherence to therapy.
The role of decay accelerating factor in the immunopathogenesis of cytomegalovirus infection
Authors: Bani-Ahmad M , El-Amouri I S , Ko C M , Lin F , Tang-Feldman Y , Oakley O R
Published: December 2010

A wide variety of the host immune elements play an influential role in the defence against cytomegalovirus (CMV) infection. However, the role of complement in the clearance of CMV infection is less well studied. Decay accelerating factor (DAF/CD55) is a membrane-bound complement regulatory protein that inhibits the formation and accelerates the decay of C3-convertase. Here we hypothesize that murine CMV (MCMV) utilizes DAF as an immunoevasive strategy through down-regulation of host adaptive responses against the virus. To test our hypothesis, DAF knock-out (DAF KO) C57BL/6 mice and wild-type (WT) littermates were infected with a sublethal dose of MCMV, and their immune responses were compared. WT mice lost 7·8% of their initial weight within the first 4 days after infection and quickly began to recover. This is in contrast to the DAF KO mice, that lost a total of 19·4% of their initial weight and did not start recovery until 6 days post-infection. Flow cytometric analysis of lung digests revealed that infected DAF KO mice had a significantly increased infiltration of inflammatory cells, the majority being CD8+ T lymphocytes. Serum levels of tumour necrosis factor (TNF)-α and interferon (IFN)-γ were also increased markedly in the DAF KO mice compared to the infected WT mice. More interestingly, increased viral genome copies (DNA) in the splenocytes of DAF KO mice was accompanied with mRNA transcripts in the DAF KO mice, an indication of active viral replication. These data suggest an intriguing effect of reduced DAF expression on host responses following in vivo MCMV infection.
YKL‐40 in type 2 diabetic patients with different levels of albuminuria
Authors: Brix Johanna‐M. , Höllerl Florian , Koppensteiner Renate , Schernthaner Guntram , Schernthaner Gerit‐H.
Published: December 2010

Eur J Clin Invest 2011; 41 (6): 589–596

Background  Type 2 diabetic patients with albuminuria have an increased risk for vascular complications. Albuminuria is related to endothelial dysfunction and plaque instability. YKL‐40 is also associated with both and elevated in nondiabetic vascular patients. We investigated YKL‐40 and its association with vascular disease in type 2 diabetic patients with albuminuria.

Material and methods  Two hundred and four patients with type 2 diabetes were included in a cross‐sectional study: One hundred and six normo‐ (No‐A), 64 micro‐ (Mi‐A) and 34 macroalbuminuric (Ma‐A) patients that did not differ for age, diabetes duration, HbA1c, body‐mass‐index, blood pressure, lipids and creatinine. YKL‐40 was measured in serum samples and determined by ELISA.

Results  YKL‐40 was significantly different in No‐A: 87 ± 57 vs. Mi‐A 119 ± 68 vs. Ma‐A 157 ± 75 ng mL−1; P < 0·001. Patients with macrovascular disease showed higher YKL‐40 than those without: 115 ± 72 vs. 87 ± 49 ng mL−1, P = 0·003. In correlation analysis, YKL‐40 was associated with urinary albumin excretion rate (AER), plasma creatinine, creatinine clearance (CC) and age. Two multivariate regression analyses were conducted: in the first one, AER and CC remained associated with YKL‐40 and in the second one AER and age.

Conclusions  This is the first report of a significant elevation of YKL‐40 in type 2 diabetic patients with albuminuria. In addition, we observed a significant association with macrovascular disease. Because we detected an association between YKL‐40 with renal, micro‐ and macrovascular disease, this protein could play an important for the increased risk of type 2 diabetic patients with albuminuria for the development of cardiovascular disease.