bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Age and Position on the CT Number of Adipose Tissues in Pigs
Authors: McEvoy Fintan J. , Madsen Mads T. , Svalastoga Eiliv L.
Published: August 2008

The location of adipose tissue depots is important in determining their significance. Research into the physical and chemical differences between these depots is therefore of interest. Using image analysis, this paper examines the influence of location on the linear attenuation coefficient of adipose tissue for X‐rays, in computed tomography (as indicated by CT number) at three time points. Nine pigs were CT scanned on three separate occasions ∼1 month apart. The mean CT number was −78, −100, and −104 for visceral adipose tissue (VAT) from the first to the final scan, respectively. The corresponding CT numbers for subcutaneous adipose tissue (SAT) were −80, −101, and −106. There was a significant difference between the CT numbers at each location at each scan (P values from 0.025 to <0.001) and between the CT numbers for each location at different times (P < 0.05). In a separate analysis of the final scan session, the mean CT number of adipose tissue at increasing distances from a mathematically defined center of the animal was determined. Regression analysis showed that the CT number of adipose tissue decreases with increasing distance from the animal's center (y = −102.7–0.04x, P < 0.001, where y is the predicted CT number for adipose tissue, from the animal center (x = 0) to the skin (x = 100)). It can thus be expected that the overall mean CT number for adipose tissue can be used as an indicator of the relative quantities of adipose tissue at each location if the mean for each is known.
The FTO Gene Is Associated With Adulthood Obesity in the Mexican Population
Authors: Villalobos‐Comparán Marisela , Flores‐Dorantes M. Teresa , Villarreal‐Molina M. Teresa , Rodríguez‐Cruz Maricela , García‐Ulloa Ana C. , Robles Lorena , Huertas‐Vázquez Adriana , Saucedo‐Villarreal Nubia , López‐Alarcón Mardia , Sánchez‐Muñoz Fausto , Domínguez‐López Aarón , Gutiérrez‐Aguilar Ruth , Menjivar Marta , Coral‐Vázquez Ramón , Hernández‐Stengele Gabriel , Vital‐Reyes Victor S. , Acuña‐Alonzo Victor , Romero‐Hidalgo Sandra , Ruiz‐Gómez Doris G. , Riaño‐Barros Daniela , Herrera Miguel F. , Gómez‐Pérez Francisco J. , Froguel Philippe , García‐García Eduardo , Tusié‐Luna M. Teresa , Aguilar‐Salinas Carlos A. , Canizales‐Quinteros Samuel
Published: August 2008

Common polymorphisms in the fat mass and obesity‐associated gene (FTO) have shown strong association with obesity in several populations. In the present study, we explored the association of FTO gene polymorphisms with obesity and other biochemical parameters in the Mexican population. We also assessed FTO gene expression levels in adipose tissue of obese and nonobese individuals. The study comprised 788 unrelated Mexican‐Mestizo individuals and 31 subcutaneous fat tissue biopsies from lean and obese women. FTO single‐nucleotide polymorphisms (SNPs) rs9939609, rs1421085, and rs17817449 were associated with obesity, particularly with class III obesity, under both additive and dominant models (P = 0.0000004 and 0.000008, respectively). These associations remained significant after adjusting for admixture (P = 0.000003 and 0.00009, respectively). Moreover, risk alleles showed a nominal association with lower insulin levels and homeostasis model assessment of B‐cell function (HOMA‐B), and with higher homeostasis model assessment of insulin sensitivity (HOMA‐S) only in nonobese individuals (P dom = 0.031, 0.023, and 0.049, respectively). FTO mRNA levels were significantly higher in subcutaneous fat tissue of class III obese individuals than in lean individuals (P = 0.043). Risk alleles were significantly associated with higher FTO expression in the class III obesity group (P = 0.047). In conclusion, FTO is a major risk factor for obesity (particularly class III) in the Mexican‐Mestizo population, and is upregulated in subcutaneous fat tissue of obese individuals.
Constitutive expression of cyclo-oxygenase 2 transgene in hepatocytes protects against liver injury
Authors: Mayoral Rafael , Mollá Belen , Flores Juana Maria , Boscá Lisardo , Casado Marta , Martín-Sanz Paloma
Published: August 2008

The effect of COX (cyclo-oxygenase)-2-dependent PGs (prostaglandins) in acute liver injury has been investigated in transgenic mice that express human COX-2 in hepatocytes. We have used three well-established models of liver injury: in LPS (lipopolysaccharide) injury in D-GalN (D-galactosamine)-preconditioned mice; in the hepatitis induced by ConA (concanavalin A); and in the proliferation of hepatocytes in regenerating liver after PH (partial hepatectomy). The results from the present study demonstrate that PG synthesis in hepatocytes decreases the susceptibility to LPS/D-GalN or ConA-induced liver injury as deduced by significantly lower levels of the pro-inflammatory profile and plasmatic aminotransferases in transgenic mice, an effect suppressed by COX-2-selective inhibitors. These Tg (transgenic) animals express higher levels of anti-apoptotic proteins and exhibit activation of proteins implicated in cell survival, such as Akt and AMP kinase after injury. The resistance to LPS/D-GalN-induced liver apoptosis involves an impairment of procaspase 3 and 8 activation. Protection against ConA-induced injury implies a significant reduction in necrosis. Moreover, hepatocyte commitment to start replication is anticipated in Tg mice after PH, due to the expression of PCNA (proliferating cell nuclear antigen), cyclin D1 and E. These results show, in a genetic model, that tissue-specific COX-2-dependent PGs exert an efficient protection against acute liver injury by an antiapoptotic/antinecrotic effect and by accelerated early hepatocyte proliferation.
The Impact of an Intensive Treatment Program on Graduate Clinicians’ Perception of Treating Children/Teens Who Stutter
Authors: Games Diane C. , Gabel Rodney
Published: August 2008

In order to evaluate graduate clinicians’ perception of treating children/teens who stutter, a six-question rating scale was administered following a period of academic coursework and prior to Fluency Friday Plus, an intensive treatment program for school-age children who stutter. The same questions were then administered to the same graduate clinicians following participation in this intensive treatment program. Results indicated a significant change in perceptions towards treating children/teens who stutter following the intensive treatment program experience.
Experimental and numerical studies of the flow over a circular cylinder at Reynolds number 3900
Authors: Parnaudeau Philippe , Carlier Johan , Heitz Dominique , Lamballais Eric
Published: August 2008

This work contributes to the study of flow over a circular cylinder at Reynolds number Re=3900. Although this classical flow is widely documented in the literature, especially for this precise Reynolds number that leads to a subcritical flow regime, there is no consensus about the turbulence statistics immediately just behind the obstacle. Here, the flow is investigated both numerically with large eddy simulation and experimentally with hot-wire anemometry and particle image velocimetry. The numerical simulation is performed using high-order schemes and a specific immersed boundary method. The present study focuses on turbulence statistics and power spectra in the near wake up to ten diameters. Statistical estimation is shown to need large integration times increasing the computational cost and leading to an uncertainty of about 10% for most flow characteristics considered in this study. The present numerical and experimental results are found to be in good agreement with previous large eddy simulation data. Contrary to this, the present results show differences compared to the experimental data found in the literature, the differences being larger than the estimated uncertainty range. Therefore, previous numerical-experimental controversy for this flow seems to be reduced with the data presented in this article.
Electrical transport properties of n-type (110)-oriented bismuth thin films grown at 110 K on glass substrates
Authors: Wu Keng Shuo , Chern Ming Yau
Published: August 2008

The structure and properties of the Bi thin films, grown by pulsed laser deposition at 110 K on glass substrates in vacuum, were found to be very different from those grown at higher temperatures. The preferred orientation of the films changed from (111), when grown at room temperature, to (110), as characterized by x-ray diffraction. The films became very smooth with a typical surface roughness of only 0.5 nm, determined by both x-ray reflectivity and atomic force microscopy. Furthermore, the conduction type changed from p to n type, indicated by the negative Hall coefficients of the films measured from 10 to 300 K. Oscillating thickness dependence of the resistivity was observed at 10 K, which is attributed to the quantum size effect. Moreover, the temperature and thickness dependences of the electrical properties show the trend that when the films are thinner, they become more metalliclike rather than semiconductive.
Surface relaxation effect on the distributions of energy and bulk stresses in the vicinity of Cu surface: An embedded-atom method study
Authors: Sun Z. H. , Wang X. X. , Wu H. A.
Published: August 2008

Molecular statics simulations combined with an embedded-atom method potential were performed to calculate the distributions of energy and bulk stresses in crystalline and amorphous Cu slabs and to examine the effect of surface relaxation on the distributions of energy and bulk stresses in the surface region. The results reveal that a release of energy and bulk stresses in the surface region occurs upon surface relaxation. The profile of energy release upon surface relaxation of a crystalline Cu slab exhibits oscillatory damping from the topmost layer to the interior layers, while that of an amorphous Cu slab exhibits monotonic decreasing. A great diversity of patterns was observed in the profiles of bulk stresses released upon surface relaxation, which may exhibit anisotropy according to the symmetry of the surface considered. Both the profiles of energy release and bulk stress release exhibit surface-orientation dependence. The present results may provide useful information to analyze different phenomena at Cu surfaces.
Electrical, thermal, and elastic properties of theMAX-phase Ti2SC
Authors: Scabarozi T. H. , Amini S. , Finkel P. , Leaffer O. D. , Spanier J. E. , Barsoum M. W. , Drulis M. , Drulis H. , Tambussi W. M. , Hettinger J. D. , Lofland S. E.
Published: August 2008

We report on the electronic, thermal, and elastic properties of the layered ternary, Ti2SC. Resistivity, Hall effect, and magnetoresistance were measured as a function of temperature between 2 and 300 K and at fields up to 9 T. The Hall coefficient is negative and roughly temperature independent. The transport results were analyzed within a two-band framework, with electrons as the dominant charge carrier. The room-temperature thermal conductivity (≈60 W/m K) is the highest of any MAX phase measured to date, with a substantial phonon contribution. The specific heat was measured from 2 to 300 K, yielding a Debye temperature of 765 K and in agreement with the Debye temperature of 745 K found from ultrasonic time-of-flight measurements. Young’s, shear, and bulk moduli from the latter measurements were 290, 125, and 145 GPa, respectively. The calculated values of the lattice parameters (a=3.2051 Å and c=11.2636 Å), and Young’s, shear, and bulk moduli (329, 138, and 179 GPa, respectively), based on the results of density functional theoretical simulations, compare favorably with measurements.
Stripe domains and spin reorientation transition in Fe78B13Si9 thin films produced by rf sputtering
Authors: Coïsson Marco , Celegato Federica , Olivetti Elena , Tiberto Paola , Vinai Franco , Baricco Marcello
Published: August 2008

Magnetic thin films have been obtained by rf sputtering from an amorphous Fe78B13Si9 target. The samples have been produced with thickness t ranging in the interval 25–1000 nm. Microstructural investigations indicate that the films have different microstructures varying from fully amorphous to partially nanocrystalline with increasing t. Magnetic hysteresis loops have been measured by means of high-sensitive magnetometry. A tailorable spin reorientation transition (SRT) from in-plane single-domain-like to out-of-plane multidomain state with increasing film thickness was observed. Magnetic force microscopy images have been obtained for all samples indicating that for t≤80 nm the magnetization lies in the film plane. For larger thickness, a stripe domain pattern has been observed, indicating the presence of a magnetic anisotropy axis perpendicular to the film plane. In this work, SRT and stripe domain structure have been studied as a function of thickness and sample microstructure.
Effects of elastic heterogeneity and anisotropy on the morphology of self-assembled epitaxial quantum dots
Authors: Kumar Chandan , Friedman Lawrence
Published: August 2008

Epitaxial self-assembled quantum dots (SAQDs) are of both technological and fundamental interest, but their reliable manufacture still presents a technical challenge. To better understand the formation, morphology, and ordering of epitaxial SAQDs, it is essential to have an accurate model that can aid further experiments and predict the trends in SAQD formation. SAQDs form because of the destabilizing effect of elastic mismatch strain, but most analytic models and some numerical models of SAQD formation either assume an elastically homogeneous anisotropic film-substrate system or assume an elastically heterogeneous isotropic system. In this work, we perform the full film-substrate elastic calculation and incorporate it into a stochastic linear model of the initial stages of SAQD formation process for the case of fast deposition followed by annealing. We find that using homogeneous elasticity can cause errors in the elastic energy density as large as 26%. The wavelength corresponding to the fastest growing mode in the linear model is used as an estimate for SAQD spacing. We calculate that homogeneous elasticity can lead to an error of about 11% in the estimated value of average spacing established during the initial stages of SAQD formation process. We also quantify the effect of elastic heterogeneity on the order estimates of SAQDs and confirm previous finding on the possibility of order enhancement by growing a film near the critical film height.
Configurational specific heat of molecular liquids by modulated calorimetry
Authors: Tombari E. , Ferrari C. , Johari G. P.
Published: August 2008

The specific heat of a liquid varies as its structure and molecular vibrational frequencies vary with the temperature. We report the magnitude of the structural or configurational part Cp,conf for five molecular liquids by measuring their dynamic and the apparent specific heats, and find that the unrelaxed or vibrational specific heat, of the equilibrium liquid, is not greatly different from that of the nonequilibrium glass. Therefore, the vibrational part of the specific heat Cp,vib does not change substantially when a glass becomes an ultraviscous liquid. This contradicts the inference that there is a large sigmoid-shape (discontinuous) increase in Cp,vib as the structure of a glass kinetically unfreezes on heating above its Tg, and further that Cp,conf is 20%–50% of the net Cp change at the glass transition.
Classical disordered ground states: Super-ideal gases and stealth and equi-luminous materials
Authors: Batten Robert D. , Stillinger Frank H. , Torquato Salvatore
Published: August 2008

Using a collective coordinate numerical optimization procedure, we construct ground-state configurations of interacting particle systems in various space dimensions so that the scattering of radiation exactly matches a prescribed pattern for a set of wave vectors. We show that the constructed ground states are, counterintuitively, disordered (i.e., possess no long-range order) in the infinite-volume limit. We focus on three classes of configurations with unique radiation scattering characteristics: (i) “stealth” materials, which are transparent to incident radiation at certain wavelengths; (ii) “super-ideal” gases, which scatter radiation identically to that of an ensemble of ideal gas configurations for a selected set of wave vectors; and (iii) “equi-luminous” materials, which scatter radiation equally intensely for a selected set of wave vectors. We find that ground-state configurations have an increased tendency to contain clusters of particles as one increases the prescribed luminosity. Limitations and consequences of this procedure are detailed.
The influences of substrate and metal properties on the magnetic response of metamaterials at terahertz region
Authors: Xia Xiaoxiang , Sun Yimin , Yang Haifang , Feng Hui , Wang Li , Gu Changzhi
Published: August 2008

The metamaterials (MMs) with planar metal arrays of split ring resonators were fabricated on quartz and silicon substrates; the influences of substrate permittivity and metal conductance on the magnetic responses of in the terahertz region were investigated. The electromagnetic (EM) responses of the metamaterials were characterized by terahertz time-domain spectroscopy. The experimental result reveals that there is a 0.39 THz redshift in the transmission spectra for the magnetic response when the substrate changes from quartz to silicon, which is in consistence with the finite-difference time-domain (FDTD) simulation. Based on the simulation and experimental results, and taking into account the EM properties of substrate materials, a modified L-C model is presented to understand the MM system in terahertz domain.
Competition between InP and In2O3 islands during the growth of InP on SrTiO3
Authors: Saint-Girons G. , Regreny P. , Cheng J. , Patriarche G. , Largeau L. , Gendry M. , Xu G. , Robach Y. , Botella C. , Grenet G. , Hollinger G.
Published: August 2008

A study of the growth of InP islands on SrTiO3 (STO) substrates is presented. The nature and crystal orientation of the islands strongly depend on the growth temperature: below 410 °C, both InP and In2O3 islands coexist, while InP islands alone are formed above this temperature. InP islands are randomly oriented in the low growth temperature range and adopt an equilibrium orientation defined by [111]InP∥[001]STO in the growth direction and [110]InP∥[100]STO in the growth plane between 410 and 475 °C. This study highlights the complexity of the growth of InP on STO, which results from a combined influence of interface chemistry and crystallographic properties as well as of the nucleation kinetics.
Iron implantation in α-Al2O3
Authors: Dézsi I. , Szűcs I. , Fetzer Cs.
Published: August 2008

Single crystal and ceramic α-Al2O3 samples were implanted with F57e ions at different fluences, and different charge states of Fe were determined. The hyperfine interaction data showed that implanted ions are in Fe0, Fe2+, and Fe3+ states depending on the fluence. It is shown that after the annealing of the implanted sample in a 2.5CO 1CO2 atmosphere Fe spinel forms. The phase diagram of Fe–Al–O in a limited concentration range was studied by determining the hyperfine interaction parameters of the formed phases after annealing the samples in different atmospheres. The hyperfine interaction parameters of an ion implanted α-Al2O3 sample annealed in a 2.5CO 1CO2 atmosphere at different temperatures were determined. The hyperfine interaction parameters of the gradually forming Fe-spinel phase were compared with the values of synthesized Fe-spinel crystal.
Optimum channel thickness of rubrene thin-film transistors
Authors: Choi Jeong-M. , Im Seongil
Published: August 2008

We report the influence of channel thickness on the field effect mobility of rubrene-based thin-film transistors (TFTs). Prior to crystallization annealing, amorphous (α) rubrene film was deposited under thickness conditions of 40, 50, 80, 120, and 160 nm by thermal evaporation on self-assembled-monolayer treated SiO2/p+-Si. Field effect mobility of the TFTs increased from almost 0 to 0.01 cm2/V s with the rubrene channel thickness until it reaches to 120 nm because the rubrene crystallization on our substrate would not be perfect below 120 nm. The mobility decreased with the thickness over 120 nm due to parasitic resistance. We thus conclude that there exists an optimum channel thickness for rubrene TFTs.
High-density magnetohydrodynamic energy conversion in a high-temperature inert gas
Authors: Murakami Tomoyuki , Okuno Yoshihiro
Published: August 2008

We describe high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a compact disk-shaped Hall-type radial-flow MHD electrical power generator is used. The state of the MHD power-generating plasma changes with increasing total inflow temperature from 8200to9400K; unstable behavior accompanied by the appearance of fine structures is transformed to a homogeneous and stable state. The attained enthalpy extraction efficiency is comparable to previous results using a conventional seeded gas. Furthermore, a high power output density is achieved even in relatively low-density magnetic flux.
Evidence for Griffiths phase in La0.4Ca0.6MnO3 film with strip-domain inclusions
Authors: Hyun Y. H. , Park J. S. , Eom T. W. , Kim G. H. , Lee Y. S. , Lee Y. P. , Prokhorov V. G. , Svetchnikov V. L.
Published: August 2008

The microstructure and the magnetic properties of La0.4Ca0.6MnO3 film, prepared by rf magnetron sputtering on a LaAlO3 substrate, have been investigated. The electron microscopy study reveals the presence of strip-domain phase with a periodic spacing of about 3c for the orthorhombic symmetry. The magnetic measurements show that in addition to the expected antiferromagnetic transition at TN≃120 K with decreasing temperature, the film manifests the Griffiths phase behavior in a wide temperature range.
Correlation between grain size and device parameters in pentacene thin film transistors
Authors: Wang S. D. , Miyadera T. , Minari T. , Aoyagi Y. , Tsukagoshi K.
Published: August 2008

We develop a general approach to precisely extract the device parameters in top-contact pentacene thin film transistors. The charge trap sites are clarified by analyzing the grain size dependence of the device parameters. The channel mobility and threshold voltage are limited by the charge traps in the channel region, most of which are located not at the grain boundaries but at the organic/insulating-layer interface. The contact resistance decreases by increasing the grain size and is controlled by the charge traps in the contact region, which are suggested to be concentrated at the grain boundaries and at the metal/organic interface.
Effects of metal electrodes on the resistive memory switching property of NiO thin films
Authors: Lee C. B. , Kang B. S. , Benayad A. , Lee M. J. , Ahn S.-E. , Kim K. H. , Stefanovich G. , Park Y. , Yoo I. K.
Published: August 2008

The effects of various metal electrodes on the resistive switching of NiO thin films were investigated. Contrary to the belief that Pt is used for its high work function, which enables Ohmic contact to p-type NiO, resistive switching was observed in films with Ta or Al electrodes with a low work function in the as-deposited state. The resistive switching of films with a Ag or Cu top electrode with a low work function and high free energy of oxidation shows the importance of the formation of an oxide layer at the metal/NiO interface.
Optical mobility in cross-type optical particle separation
Authors: Kim Sang Bok , Jung Eunjung , Sung Hyung Jin , Kim Sang Soo
Published: August 2008

The optical mobilities of particles in a cross-type particle separation system were measured experimentally. Three particles were chosen to test the effects of optical mobility, namely, polystyrene latex, polymethylmethacrylate, and silica particles. The particles, which had the same optical mobility, showed identical behavior even though their sizes and refractive indices were very different. The optical mobility was validated by measuring the retention distance where each particle was deflected by the radiation force.
A note on the binary interaction potential in complex (dusty) plasmas
Authors: Khrapak S. A. , Morfill G. E.
Published: August 2008

The effect of ion-neutral collisions on the potential of interaction between a pair of negatively charged grains in isotropic weakly collisional plasmas is investigated. Two interaction mechanisms are considered: Electric repulsion between like-charged grains and attraction due to the so-called “ion shadow” effect. It is demonstrated that in the presence of collisions, both interaction potentials exhibit Coulomb-like ∝r−1 decay at large distances. A necessary condition for the existence of long-range attraction is derived. The obtained results are then used to reconsider the possibility of liquid-vapor critical point occurrence in complex plasmas.
Manipulation of paramagnetic particles using a nanoscale asymmetric magnetic potential
Authors: Helseth L. E. , Johansen T. H. , Fischer T. M.
Published: August 2008

We report how one-dimensional nanomagnets can be used to manipulate paramagnetic particles located in liquid systems. It is shown that by using an asymmetric magnetic potential well, single particles can be efficiently sorted out from a one-dimensional array and moved along the phase boundary confining the array.
Femtosecond acceleration of electrons under high electric fields in bulk GaAs investigated by time-domain terahertz spectroscopy
Authors: Zhu Y. M. , Unuma T. , Shibata K. , Hirakawa K.
Published: August 2008

We have investigated terahertz emission from undoped bulk GaAs photoexcited by femtosecond laser pulses under strong bias electric fields, F, up to 300kV∕cm. The initial positive signal in the terahertz waveforms, which is usually interpreted as electron acceleration in the Γ-valley, is found to increase with increasing F for F<50kV∕cm, but to start decreasing gradually above 50kV∕cm. The observed behavior suggests that the effective acceleration mass of electrons significantly increases with increasing F. The mass enhancement is due most likely to band mixing between the Γ- and the higher satellite valleys under high electric fields.
In-line holography for the characterization of ultrafast laser filamentation in transparent media
Authors: Papazoglou D. G. , Tzortzakis S.
Published: August 2008

A powerful experimental method, based on holographic microscopy, is used to retrieve the spatiotemporal distribution of small (<10−3) refractive index perturbations induced by ultrafast laser pulses in transparent media. A numerical iterative wavefront propagation approach is used to accurately reconstruct both the phase and the amplitude of the perturbed probe beam wavefront, while Abel inversion recovers the exact three dimensional distribution of the perturbation. For demonstration, a laser filament induced plasma string in air is fully characterized.
People on the Move: Exploring the Functional Roles of Deprived Neighbourhoods
Authors: Robson Brian , Lymperopoulou Kitty , Rae Alasdair
Published: August 2008

Given the neighbourhood focus of much regeneration policy, we need to know more about the functional roles that neighbourhoods play in the way that households move within the housing market and hence about the different functional types of neighbourhood amongst deprived areas. Such knowledge would help both to guide the priorities of policy and to interpret the probability of policy interventions being successful. This exploratory study draws on an evaluation of the British government's National Strategy for Neighbourhood Renewal, part of which entails an interpretation of household mobility data from the 2001 Census. It suggests four categories of neighbourhood—transit, escalator, isolate, and improver areas—based on the relationship between where households move to and move from, focused on the 20% most deprived lower super output areas in England. Evidence on the ground suggests the plausibility of the different functional roles played by the four neighbourhood types. Some continuing conundrums—the robustness of the categorisation, the need to take account of the spatial context of deprived areas, and the difference between movers and stayers—are discussed as a prelude to further continuing research.
Using Choice Experiments to Explore the Spatial Distribution of Willingness to Pay for Rural Landscape Improvements
Authors: Campbell Danny , Hutchinson W George , Scarpa Riccardo
Published: August 2008

We report findings from a choice experiment survey designed to estimate the economic benefits of policy measures to improve the rural landscape in the Republic of Ireland. Using a panel mixed logit specification to account for unobserved taste heterogeneity we derived individual-specific willingness-to-pay (WTP) estimates for each respondent in the sample. We subsequently investigated the spatial dependence of these estimates. Results suggest the existence of positive spatial autocorrelation for all rural landscape attributes. As a means of benefit transfer, kriging methods were employed to interpolate WTP estimates across the whole of the Republic of Ireland. The kriged WTP surfaces confirm the existence of spatial dependence and illustrate the implied spatial variation and regional disparities in WTP for all the rural landscape improvements investigated.
What is the Reference in Reference Repulsion?
Authors: Wiese Mark , Wenderoth Peter
Published: August 2008

Reference repulsion is a mechanism posited to explain systematic biases of direction judgment of single drifting dot displays (Rauber and Treue, 1998 Perception27 393–402). Rauber and Treue obtained systematic but, surprisingly, very different effects depending upon whether standard and comparison stimuli were presented simultaneously or successively. Successive effects were described as exhibiting repulsion from both vertical and horizontal cardinal axes, whereas simultaneous effects showed repulsion from horizontal only. We contend that the proposed mechanism makes no testable predictions because the so-called reference can only be specified a posteriori, a fact acknowledged by Rauber and Treue. We attempted to replicate Rauber and Treue's experiments, but we obtained no systematic biases of direction judgment. Comparisons across several studies suggest that errors in direction judgments of single drifting dot patterns vary widely in magnitude and direction, as might be expected with what are essentially baseline or pretest measures. In our view, reference repulsion describes neither a real perceptual mechanism nor a predictable pattern of direction misjudgments.
The Influence of Recent Experience on Perceptions of Attractiveness
Authors: Cooper Philip A , Maurer Daphne
Published: August 2008

Adults rate average faces as more attractive than most of the faces used in the creation of the average. One explanation for this is that average faces appear as both more familiar and more attractive because they resemble internal face prototypes formed from experience. Here we evaluated that explanation by examining the influence of recent experience on participants' subsequent judgments of attractiveness. Participants first performed a memory task lasting 8 min in which all of the female faces to be remembered had their features placed in a low, average, or high position, depending on experimental condition. In what was described as a separate experiment, participants then moved the features of a female face with averaged features to their most attractive vertical location. The most attractive location was affected by the faces seen during the memory task, with participants who saw faces with features in the high position placing features in higher locations than participants who saw faces with features in either the low or average positions. The results demonstrate that perceptions of attractiveness are influenced by recent experience, and suggest that internal face prototypes are constantly being updated by experience.
The impact of defoliation on nitrogen translocation patterns in the woody invasive plant, Buddleia davidii
Authors: Thomas Marc M. , Millard Pete , Watt Michael S. , Turnbull Matthew H. , Peltzer Duane , Whitehead David
Published: August 2008

The influence of defoliation on nitrogen (N) re-translocation and the source for N remobilisation by the invasive shrub, Buddleia davidii Franch. (buddleia) was determined. Eighty plants were grown over two growing seasons, and half were repeatedly defoliated by removing 66% of their leaf area. During the second season, the N supply was labelled with 15N (10 atom% enrichment), to distinguish the use of stored N (unlabelled) from N taken up by roots (labelled) for growth. Defoliation significantly decreased root (39%) and total biomass (26%). Old leaves were the main source of N for remobilisation which was accelerated and increased (by 50% in the second season) in response to defoliation. In spring, root uptake of N increased by 57% in defoliated plants. Thus, defoliation induced changes in N remobilisation and uptake as compensatory growth increased the demand for N. Continued leaf removal decreased the pool of stored N and caused a significant decline in biomass production, especially in roots (39%) and flowers (31%). This has important implications for the efficacy of defoliation as a control measure, as smaller roots suggest a reduced capacity for uptake of nutrients from the soil and reduced flower production may assist in reducing the invasive spread of the species. These findings clearly show that, although the success of B. davidii is associated, in part, with efficient remobilisation of N from storage, this advantage can be overcome by continued defoliation.
Mechanisms linking plant productivity and water status for a temperate Eucalyptus forest flux site: analysis over wet and dry years with a simple model
Authors: Pepper David A. , McMurtrie Ross E. , Medlyn Belinda E. , Keith Heather , Eamus Derek
Published: August 2008

A simple process-based model was applied to a tall Eucalyptus forest site over consecutive wet and dry years to examine the importance of different mechanisms linking productivity and water availability. Measured soil moisture, gas flux (CO2, H2O) and meteorological records for the site were used. Similar levels of simulated H2O flux in ‘wet’ and ‘dry’ years were achieved when water availability was not confined to the first 1.20 m of the soil profile, but was allowed to exceed it. Although the simulated effects of low soil and atmospheric water content on CO2 flux, presumably via reduction in stomatal aperture, also acted on transpiration, they were offset in the dry year by a higher vapour-pressure deficit. A sensitivity analysis identified the processes that were important in wet versus dry years, and on an intra-annual timeframe. Light-limited productivity dominated in both years, except for the driest period in the dry year. Vapour-pressure deficit affected productivity across more of each year than soil moisture, but both effects were larger in the dry year. The introduction of a reduced leaf area tended to decrease sensitivity in the dry year. Plant hydraulic architecture that increases plant available water, maximises productivity per unit water use and achieves lower sensitivity to low soil moisture levels should minimise production losses during dry conditions.
Photosynthesis and respiration decline with light intensity in dominant and suppressed Eucalyptus globulus canopies
Authors: O'Grady A. P. , Worledge D. , Wilkinson A. , Battaglia M.
Published: August 2008

Within canopy gradients in light-saturated photosynthesis (Amax), foliar nitrogen ([N]area) and leaf dark respiration (R15) were studied in the canopies of dominant and suppressed trees within an even-aged (4-year-old) Eucalyptus globulus (Labill) stand in southern Tasmania. Despite being an even-aged stand growing in a relatively uniform environment with respect to nutrient and water availability, the stand exhibited considerable structural complexity. Diameter at 1.3 m ranged between 3 cm and 21 cm, trees average 12 m height and stand leaf area index was ~6 m2 m–2 leading to strong gradients in light availability. We were interested in understanding the processes governing canopy production in trees of contrasting dominance classes. Vertical gradients in photosynthesis and foliar respiration were studied within the canopies of dominant and suppressed trees during 2006 and 2007. Amax varied from ~18 μmol m–2 s–1 in the upper canopy to 3 μmol m–2 s–1 at lower canopy positions. On average, Amax were higher in the dominant trees than in the suppressed trees. However, at any given height, Amax were similar in suppressed and dominant trees and were strongly related to leaf nitrogen content. Dark respiration varied from ~1.4 μmol m–2 s–1 in the upper canopy to 0.2 μmol m–2 s–1 in the lower canopy positions. In contrast to the patterns for Amax, dark respiration rates in the suppressed trees were higher than dominant trees at similar canopy positions. Respiration rates were also strongly related to [N]area and to Amax.
Pedotransfer functions for predicting the hydraulic properties of Indian soils
Authors: Adhikary Partha Pratim , Chakraborty Debashis , Kalra Naveen , Sachdev C. B. , Patra A. K. , Kumar Sanjeev , Tomar R. K. , Chandna Parvesh , Raghav Dhwani , Agrawal Khushboo , Sehgal Mukesh
Published: August 2008

Most of the data pertaining to Indian soils are limited to the major soil separates, sand, silt, and clay. We examined the possibilities of using these parameters to describe the hydraulic characteristics of the soils of India. The final or steady-state infiltration rate, which is mainly profile-controlled, showed a power function relationship with the maximum and the average clay content in the soil profile. The saturated hydraulic conductivity also showed a similar relationship with the silt + clay content. The soil water content at a given suction could be satisfactorily predicted using the percentage of major soil separates, sand, silt, and clay. The coefficients in the soil water function ψ(θ) were linearly related to the sand content. Non-linear regression equations were developed to predict these coefficients using the percentages of sand and clay in soils. The equations proved to be quite satisfactory for a wide range of textures and provided reasonably accurate estimates of the soil water characteristic curve from a minimum of readily available data.
Effect of biosolids on the organic matter content and phosphorus chemical fractionation of heated volcanic Chilean soils
Authors: Antilén Mónica , Briceño Margarita , Galindo Gerardo , Escudey Mauricio
Published: August 2008

Biosolids produced in wastewater treatment plants with high organic matter (OM) content can be used to reclaim organic components in heated soils. The impact of biosolids amendment on soil pH, electric conductivity (EC), exchangeable cations, OM content, and phosphorus (P) chemical fractionation in 3 heated volcanic soils in southern Chile was investigated in a 4-month incubation study. In amended heated soils, pH, EC, OM content, and exchangeable cations were greater than in control soils. The control OM content was increased by biosolids, and the incubation time effect to reclaim the organic component was important in Andisols and Inceptisols. The pH decreased with incubation time, reflecting the buffer capacity of volcanic soils, and EC increased. In the heated incubated soils, inorganic P was in general higher than organic P. Phosphorus distribution showed little difference with incubation time, showing that after a short time (4 months) biosolids P was not significantly redistributed to organic P; however, more available P forms (Olsen P) were determined. It can be concluded that biosolids are a valid option for reclaiming the OM content lost in soils affected by forest fires. However, an important amount of inorganic P, strongly fixed in volcanic soils, with a relative contribution of available forms for plants, could potentially contribute to soil and water pollution.
Relations between sorption behavior and electrokinetic remediation effect in soils contaminated with heavy metals
Authors: Shen Zhemin , Ju Bingxin , Chen Xuejun , Wang Wen-hua
Published: August 2008

Adsorption–desorption is an important mechanism for controlling metal mobility in soil and has a large effect on remediation efficiency. Very little research has examined the relations between heavy metal sorption behaviour and electrokinetic (EK) remediation effect. Four typical soil samples in China (Chernozem, Fluvisol, Yellow brown earth, and Purple soil) were studied. Adsorption isotherms were fit to Freundlich equations. EK removal ratios in the 4 soils were: Purple soil > Yellow brown earth > Fluvisol > Chernozem. Results show that the influencing characteristics significant to Cd EK removal order as follows: total organic carbon (TOC) > 1/n (Freundlich constant) > clay ratio > K (Freundlich constant) > cation exchange capacity > background pH. When 1/n (Freundlich constant) increases by 0.124 or TOC increases by 0.858 g/kg in soils, EK removal ratio (%) of Cd decreases by 1.0%. A ‘2-reactions’ mechanism during EK remediation is speculated, including rapid and slow reactions. Fast reactions are attributed to H+–M2+ exchange processes occurring on the surfaces of different inorganic phases and to the dissolution of the water-insoluble precipitates. Slow irreversible reactions refer to H+ ions exchanging with metal ions bound in the internal lattice sites and organic matter being oxidised by oxidants produced by electrochemical reactions. Slow reactions limit the EK remediation effect.
Huntington's disease protein contributes to RNA-mediated gene silencing through association with Argonaute and P bodies
Authors: Savas Jeffrey N. , Makusky Anthony , Ottosen Søren , Baillat David , Then Florian , Krainc Dimitri , Shiekhattar Ramin , Markey Sanford P. , Tanese Naoko
Published: August 2008

Huntington's disease is a dominant autosomal neurodegenerative disorder caused by an expansion of polyglutamines in the huntingtin (Htt) protein, whose cellular function remains controversial. To gain insight into Htt function, we purified epitope-tagged Htt and identified Argonaute as associated proteins. Colocalization studies demonstrated Htt and Ago2 to be present in P bodies, and depletion of Htt showed compromised RNA-mediated gene silencing. Mouse striatal cells expressing mutant Htt showed fewer P bodies and reduced reporter gene silencing activity compared with wild-type counterparts. These data suggest that the previously reported transcriptional deregulation in HD may be attributed in part to mutant Htt's role in post-transcriptional processes.
Zinc porphyrin: A fluorescent acceptor in studies of Zn-cytochromecunfolding by fluorescence resonance energy transfer
Authors: Ensign Amy A. , Jo Iris , Yildirim Ilyas , Krauss Todd D. , Bren Kara L.
Published: August 2008

FRET between the zinc porphyrin (ZnP) chromophore in zinc-substituted cytochromec(Zn-cytc) and an Alexa Fluor dye attached to specific surface sites was used to characterize Zn-cytcunfolding. The use of ZnP as a fluorescent acceptor eliminates the need to doubly label the protein with exogenous dyes to perform FRET experiments in which both donor and acceptor fluorescence is monitored. The requirement for attachment of only one dye also minimizes perturbation to the protein. This sensitive technique allowed for the determination of distances between the label placed at six different sites and ZnP through a range of denaturant concentrations. Fitting of the data to a three-state model provides distances in the unfolding intermediate. The use of ZnP as a fluorescent acceptor of energy in FRET has a significant potential for application to a range of other systems including heme-binding proteins and proteins to which a covalently attached heme tag may be added.
Splenic nerve is required for cholinergic antiinflammatory pathway control of TNF in endotoxemia
Authors: Rosas-Ballina Mauricio , Ochani Mahendar , Parrish William R. , Ochani Kanta , Harris Yael T. , Huston Jared M. , Chavan Sangeeta , Tracey Kevin J.
Published: August 2008

The autonomic nervous system maintains homeostasis through its sympathetic and parasympathetic divisions. During infection, cells of the immune system release cytokines and other mediators that cause fever, hypotension, and tissue injury. Although the effect of cytokines on the nervous system has been known for decades, only recently has it become evident that the autonomic nervous system, in turn, regulates cytokine production through neural pathways. We have previously shown that efferent vagus nerve signals regulate cytokine production through the nicotinic acetylcholine receptor subunit α7, a mechanism termed “the cholinergic antiinflammatory pathway.” Here, we show that vagus nerve stimulation during endotoxemia specifically attenuates TNF production by spleen macrophages in the red pulp and the marginal zone. Administration of nicotine, a pharmacological agonist of α7, attenuated TNF immunoreactivity in these specific macrophage subpopulations. Synaptophysin-positive nerve endings were observed in close apposition to red pulp macrophages, but they do not express choline acetyltransferase or vesicular acetylcholine transporter. Surgical ablation of the splenic nerve and catecholamine depletion by reserpine indicate that these nerves are catecholaminergic and are required for functional inhibition of TNF production by vagus nerve stimulation. Thus, the cholinergic antiinflammatory pathway regulates TNF production in discrete macrophage populations via two serially connected neurons: one preganglionic, originating in the dorsal motor nucleus of the vagus nerve, and the second postganglionic, originating in the celiac-superior mesenteric plexus, and projecting in the splenic nerve.
An allosteric model of calmodulin explains differential activation of PP2B and CaMKII
Authors: Stefan Melanie I. , Edelstein Stuart J. , Le Novère Nicolas
Published: August 2008

Calmodulin plays a vital role in mediating bidirectional synaptic plasticity by activating either calcium/calmodulin-dependent protein kinase II (CaMKII) or protein phosphatase 2B (PP2B) at different calcium concentrations. We propose an allosteric model for calmodulin activation, in which binding to calcium facilitates the transition between a low-affinity [tense (
T
)] and a high-affinity [relaxed (
R
)] state. The four calcium-binding sites are assumed to be nonidentical. The model is consistent with previously reported experimental data for calcium binding to calmodulin. It also accounts for known properties of calmodulin that have been difficult to model so far, including the activity of nonsaturated forms of calmodulin (we predict the existence of open conformations in the absence of calcium), an increase in calcium affinity once calmodulin is bound to a target, and the differential activation of CaMKII and PP2B depending on calcium concentration.