bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative study of the effects of thermal treatment on the optical properties of hydrogenated amorphous silicon-oxycarbide
Authors: Gallis Spyros , Nikas Vasileios , Huang Mengbing , Eisenbraun Eric , Kaloyeros Alain E.
Published: July 2007

Findings are presented from a systematic study of the effects of postdeposition thermal treatment on the optical characteristics of hydrogenated amorphous silicon-oxycarbide (a-SiCxOyHz) materials. Three different classes of a-SiCxOyHz films: SiC-like (SiC1.08O0.07H0.21), Si-C-O (SiC0.50O1.20H0.22), and SiO2-like (SiC0.20O1.70H0.24), were deposited by thermal chemical vapor deposition. The effects of thermal annealing on the compositional and optical properties of the resulting films were characterized using Fourier-transform infrared spectroscopy, x-ray photoelectron spectroscopy, nuclear reaction analysis, and spectroscopic ultraviolet-visible ellipsometry. As the Si-C-O system evolved from a SiC-like to SiO2-like matrix, its refractive index and optical absorption strength decreased, while its optical band gap increased. Thermal annealing between 500 and 1100 °C resulted in hydrogen desorption from and densification of the a-SiCxOyHz films. Concurrently, thermally induced changes were also observed for the optical properties of the films, as evidenced by an increase in film refractive index and an accompanying decrease in optical gap. These changes are analyzed in the context of the underlying physical processes, particularly modifications in the electronic configuration (bonding) and hydrogen desorption mechanisms. Furthermore, based on the observed structural and optical properties of the thermally treated a-SiCxOyHz films, the Si-C-O matrix was employed in the successful development of an Er-doped Si-C-O system with efficient Er excitation and strong room-temperature photoluminescence emission around 1540 nm within a broad (460–600 nm) excitation band. As such, a-Si-C-O represents a material system that provides considerably efficient energy transfer mechanisms at the same Er concentration level than previously investigated Si-based materials.
Alternating current electric-field-induced tunable microstructures and electrohydrodynamic convection properties observed in azo-dye-doped MBBA liquid crystal cells
Authors: Xu Z. D. , He Y. N. , Guo M. C. , Wang X. G.
Published: July 2007

Alternating current (ac) electric-field-induced microstructures and electrohydrodynamic convection properties were studied for a guest-host liquid crystal (LC) system. The LC (MBBA) was doped with a newly synthesized azo-dye and filled in a LC cell. When the applied ac electric-field voltage was fixed at 13.5 V (Vrms), microstructures in the LC cell varied with the frequency (f) of the electric field. The probed He-Ne laser light displayed a hexagonal diffracted pattern when f=4.3 Hz, a square symmetry pattern when f=17.38 Hz, and a new hexagonal symmetry pattern when f=34.07 Hz. The first-order diffraction intensities along the x-axis direction (I1−x(t)) and y-axis direction (I1−y(t)) showed different time evolution tendency. At the same time, the phase shift (φ) between I1−x(t) and second-order diffraction intensity I2−x(t) was found to be dependent on the frequency.
Effect of Nd modification on electrical properties of mixed-layer Aurivillius phase Bi4Ti3O12-SrBi4Ti4O15
Authors: Wang Wei , Gu Shi-Pu , Mao Xiang-Yu , Chen Xiao-Bing
Published: July 2007

The effect of Nd modification on ferro-, piezo-, and dielectric properties of intergrowth Bi4Ti3O12-SrBi4Ti4O15 ceramics was investigated. X-ray diffraction and Raman scattering were used to identify the crystal phase and to distinguish the doping sites. With increasing Nd content up to 0.50, both remanent polarization (2Pr) and piezoelectric coefficient (d33) were found to increase and reach the maximum value of 33.2 μC/cm2 and 14 pC/N, respectively, which gained an enlargement over 1.7 times in 2Pr and a desirable 75% increment in d33 value. However, further Nd modification starts to deteriorate the ferro- and piezoelectric behavior. Impedance spectroscopy shows the activation energy of conductivity increased with increasing Nd content, which can be regarded as direct proof of the restraint of oxygen vacancies. The thermal variations of dielectric permittivity and loss tan δ with Nd content show the characteristic of diffuse phase transformation while the convincible defect-related relaxation phenomenon was not found. Interestingly, in contrast to La modification, Nd modification does not induce the relaxor behavior even at very high doping content.
Growth of crystalline γ-Al2O3 on Si by molecular beam epitaxy: Influence of the substrate orientation
Authors: Merckling C. , El-Kazzi M. , Saint-Girons G. , Hollinger G. , Largeau L. , Patriarche G. , Favre-Nicolin V. , Marty O.
Published: July 2007

This work reports on the molecular beam epitaxy of high quality single crystal γ-Al2O3 thin films on Si(001) and Si(111) substrates. For both substrate orientations, film surfaces are found to be smooth and the oxide-Si interfaces are atomically abrupt without interfacial layers. Reflection high energy electron diffraction, x-ray diffraction, and transmission electronic microscopy characterizations were used to study the epitaxial relationship and the structural quality of the γ-Al2O3 layers depending on the Si substrate orientation. On Si(111), the alumina layers present a high crystalline quality. Evidence is made for a “two-for-three” unit cell indirect epitaxial relationship between γ-Al2O3 and Si(111). On Si(001), after a transition from cubic to hexagonal surface symmetry, the growth planes of γ-Al2O3 change from (001) to (111) leading to a bidomain growth.
Mechanism of large area dislocation defect reduction in GaN layers on AlN∕Si (111) by substrate engineering
Authors: Jamil M. , Grandusky J. R. , Jindal V. , Tripathi N. , Shahedipour-Sandvik F.
Published: July 2007

A reduction of edge dislocations in the GaN layer on Si substrate by almost an order of magnitude to 8.0×107∕cm2 and reduction in screw dislocations by a factor greater than 4 are achieved for the film grown on the Si (111) substrate engineered to have a polycrystalline defective layer at the AlN∕Si interface. The formation of a polycrystalline defective layer at the AlN∕Si interface by N+ ion implantation provides substrate conditions that result in a heteroepitaxial GaN film with much improved surface morphology and better crystal quality as compared to the film grown directly on AlN∕Si. A mechanism of dislocation defect reduction in the epitaxial film is given based on the detailed study of AlN∕Si interfaces as well as the evolution of the AlN buffer layer in the context of this substrate engineering technique, which shows partial decoupling of the III-nitride layers from the substrate to be responsible for the improved characteristics.
Charge characterization in metal-gate/high-κ layers: Effect of post-deposition annealing and gate electrode
Authors: O’Sullivan B. J. , Pourtois G. , Kaushik V. S. , Schram T. , Kittl J. A. , Pantisano L. , De Gendt S. , Heyns M.
Published: July 2007

The effect of varying interfacial SiO2 and high-κ thickness on charge density within the gate stack are examined. It is demonstrated that there is a significant effect of the gate electrode on the charge density levels within the stack, with one order of magnitude lower charge in the case of Ni3Si2 electrodes, than in the case of tantalum-rich metal electrodes. The effect of post-deposition annealing on high-κ HfSixOy(Nz) stacks is less significant that that of the electrode. The reasons behind these findings are discussed.
Long range and selective coupler for superconducting flux qubits
Authors: Nakano Hayato , Kakuyanagi Kosuke , Ueda Masahito , Semba Kouichi
Published: July 2007

The authors propose a qubit-qubit coupling scheme for superconducting flux quantum bits (qubits), where quantized Josephson junction resonator and microwave irradiation are utilized. The junction is used as a tunable inductance controlled by changing the bias current flowing through the junction, and thus the circuit works as a tunable resonator. This enables them to make any qubits interact with the resonator. Entanglement between two of many qubits whose level splittings satisfy some conditions is formed by microwave irradiation causing a two-photon Rabi oscillation. Since the size of the resonator can be as large as submillimeters and qubits interact with it via mutual inductance, their scheme makes it possible to construct a quantum gate involving remote qubits.
The curli nucleator protein, CsgB, contains an amyloidogenic domain that directs CsgA polymerization
Authors: Hammer Neal D. , Schmidt Jens C. , Chapman Matthew R.
Published: July 2007

Curli are functional amyloid fibers assembled by enteric bacteria such as
Escherichia coli
and
Salmonella
spp. In
E. coli
, the polymerization of the major curli fiber subunit protein CsgA into an amyloid fiber depends on the minor curli subunit protein, CsgB. The outer membrane-localized CsgB protein shares ≈30% sequence identity with the amyloid-forming protein CsgA, suggesting that CsgB might also have amyloidogenic properties. Here, we characterized the biochemical properties of CsgB and the molecular basis for CsgB-mediated nucleation of CsgA. Deletion analysis revealed that a CsgB molecule missing 19 amino acids from its C terminus (CsgB
trunc
) was not outer membrane-associated, but secreted away from the cell. CsgB
trunc
was overexpressed and purified from the extracellular milieu of cells as an SDS-soluble, nonaggregated protein. Soluble CsgB
trunc
assembled into fibers that bound to the amyloid-specific dyes Congo red and thioflavin-T. CsgB
trunc
fibers were able to seed soluble CsgA polymerization
in vitro
. CsgB
trunc
displayed modest nucleator activity
in vivo
, as demonstrated by its ability to convert extracellular CsgA into an amyloid fiber. Unlike WT CsgB, CsgB
trunc
was only able to act as a nucleator when cells were genetically manipulated to secrete higher concentrations of CsgA. This work represents a unique demonstration of functional amyloid nucleation and it suggests an elegant model for how
E. coli
guides efficient amyloid fiber formation on the cell surface.
Ancient and continuing Darwinian selection on
insulin-like growth factor II
in placental fishes
Authors: O'Neill Michael J. , Lawton Betty R. , Mateos Mariana , Carone Dawn M. , Ferreri Gianni C. , Hrbek Tomas , Meredith Robert W. , Reznick David N. , O'Neill Rachel J.
Published: July 2007

Despite abundant examples of both adaptation at the level of phenotype and Darwinian selection at the level of genes, correlations between these two processes are notoriously difficult to identify. Positive Darwinian selection on genes is most easily discerned in cases of genetic conflict, when antagonistic evolutionary processes such as a Red Queen race drive the rate of nonsynonymous substitution above the neutral mutation rate. Genomic imprinting in mammals is thought to be the product of antagonistic evolution coincident with evolution of the placenta, but imprinted loci lack evidence of positive selection likely because of the ancient origin of viviparity in mammals. To determine whether genetic conflict is a general feature of adaptation to placental reproduction, we performed comparative evolutionary analyses of the
insulin-like growth factor II
(
IGF2
) gene in teleost fishes. Our analysis included several members of the order Cyprinodontiformes, in which livebearing and placentation have evolved several times independently. We found that
IGF2
is subject to positive Darwinian selection coincident with the evolution of placentation in fishes, with particularly strong selection among lineages that have evolved placentation recently. Positive selection is also detected along ancient lineages of placental livebearing fishes, suggesting that selection on
IGF2
function is ongoing in placental species. Our observations provide a rare example of natural selection acting in synchrony at the phenotypic and molecular level. These results also constitute the first direct evidence of parent–offspring conflict driving gene evolution.
A viral adaptor protein modulating casein kinase II activity induces cytopathic effects in permissive cells
Authors: Nüesch Jürg P. F. , Rommelaere Jean
Published: July 2007

Autonomous parvoviruses induce severe morphological and physiological alterations in permissive host cells, eventually leading to cell lysis and release of progeny virions. Viral cytopathic effects (CPE) result from specific rearrangements and destruction of cytoskeletal micro- and intermediate filaments. We recently reported that inhibition of endogenous casein kinase II (CKII) protects target cells from parvovirus minute virus of mice (MVM)-induced CPE, pointing to this kinase as an effector of MVM toxicity. The present work shows that the parvoviral NS1 protein mediates CKII-dependent cytoskeletal alterations and cell death. NS1 can act as an adaptor molecule, linking the cellular protein kinase CKIIα to tropomyosin and thus modulating the substrate specificity of the kinase. This action results in an altered tropomyosin phosphorylation pattern both
in vitro
and in living cells. The capacity of NS1 to induce CPE was impaired by mutations abolishing binding with either CKIIα or tropomyosin. The cytotoxic adaptor function of NS1 was confirmed with fusion peptides, where the tropomyosin-binding domain of NS1 and CKIIα are physically linked. These adaptor peptides were able to mimic NS1 in its ability to induce death of transformed MVM-permissive cells.
Cyclophilin A participates in the nuclear translocation of apoptosis-inducing factor in neurons after cerebral hypoxia-ischemia
Authors: Zhu Changlian , Wang Xiaoyang , Deinum Johanna , Huang Zhiheng , Gao Jianfeng , Modjtahedi Nazanine , Neagu Martha R. , Nilsson Michael , Eriksson Peter S. , Hagberg Henrik , Luban Jeremy , Kroemer Guido , Blomgren Klas
Published: July 2007

Upon cerebral hypoxia-ischemia (HI), apoptosis-inducing factor (AIF) can move from mitochondria to nuclei, participate in chromatinolysis, and contribute to the execution of cell death. Previous work (Cande, C., N. Vahsen, I. Kouranti, E. Schmitt, E. Daugas, C. Spahr, J. Luban, R.T. Kroemer, F. Giordanetto, C. Garrido, et al. 2004. Oncogene. 23:1514–1521) performed in vitro suggests that AIF must interact with cyclophilin A (CypA) to form a proapoptotic DNA degradation complex. We addressed the question as to whether elimination of CypA may afford neuroprotection in vivo. 9-d-old wild-type (WT), CypA+/−, or CypA−/− mice were subjected to unilateral cerebral HI. The infarct volume after HI was reduced by 47% (P = 0.0089) in CypA−/− mice compared with their WT littermates. Importantly, CypA−/− neurons failed to manifest the HI-induced nuclear translocation of AIF that was observed in WT neurons. Conversely, CypA accumulated within the nuclei of damaged neurons after HI, and this nuclear translocation of CypA was suppressed in AIF-deficient harlequin mice. Immunoprecipitation of AIF revealed coprecipitation of CypA, but only in injured, ischemic tissue. Surface plasmon resonance revealed direct molecular interactions between recombinant AIF and CypA. These data indicate that the lethal translocation of AIF to the nucleus requires interaction with CypA, suggesting a model in which two proteins that normally reside in separate cytoplasmic compartments acquire novel properties when moving together to the nucleus.
IL-25 augments type 2 immune responses by enhancing the expansion and functions of TSLP-DC–activated Th2 memory cells
Authors: Wang Yui-Hsi , Angkasekwinai Pornpimon , Lu Ning , Voo Kui Shin , Arima Kazuhiko , Hanabuchi Shino , Hippe Andreas , Corrigan Chris J. , Dong Chen , Homey Bernhard , Yao Zhengbin , Ying Sun , Huston David P. , Liu Yong-Jun
Published: July 2007

Interleukin (IL) 25 (IL-17E), a distinct member of the IL-17 cytokine family, plays important roles in evoking T helper type 2 (Th2) cell–mediated inflammation that features the infiltrations of eosinophils and Th2 memory cells. However, the cellular sources, target cells, and underlying mechanisms remain elusive in humans. We demonstrate that human Th2 memory cells expressing distinctive levels of IL-25 receptor (R) are one of the responding cell types. IL-25 promotes cell expansion and Th2 cytokine production when Th2 central memory cells are stimulated with thymic stromal lymphopoietin (TSLP)–activated dendritic cells (DCs), homeostatic cytokines, or T cell receptor for antigen triggering. The enhanced functions of Th2 memory cells induced by IL-25 are associated with sustained expression of GATA-3, c-MAF, and JunB in an IL-4–independent manner. Although keratinocytes, mast cells, eosinophils, and basophils express IL-25 transcripts, activated eosinophils and basophils from normal and atopic subjects were found to secrete bioactive IL-25 protein, which augments the functions of Th2 memory cells. Elevated expression of IL-25 and IL-25R transcripts was observed in asthmatic lung tissues and atopic dermatitis skin lesions, linking their possible roles with exacerbated allergic disorders. Our results provide a plausible explanation that IL-25 produced by innate effector eosinophils and basophils may augment the allergic inflammation by enhancing the maintenance and functions of adaptive Th2 memory cells.
A stock rebuilding algorithm featuring risk assessment and an optimization strategy of single or multispecies fisheries
Authors: Gröger Joachim P. , Rountree Rodney A. , Missong Martin , Rätz Hans-Joachim
Published: July 2007

Gröger, J. P., Rountree, R. A., Missong, M., and Rätz, H-J. 2007. A stock rebuilding algorithm featuring risk assessment and an optimization strategy of single or multispecies fisheries. – ICES Journal of Marine Science, 64: 1101–1115. We present a simple but flexible stock-rebuilding algorithm model that features ideas of risk assessment, with all constraints set up explicitly, and with clear optimality for controlling fishing effort (or fishing mortality) and maximizing landings (or economic value). In contrast to the conventional approach, our approach does not predict future stock development from historical stock dynamics, but provides directly optimal annual F values and associated optimum catch quotas for a given planning horizon. Hence, the F values are not estimated retrospectively, but are realizations of a control variable created through the optimization process. The optimal solution is based on maximization of a non-linearly constrained objective function for catch or yield, whereas the constraints inter alia include biomass targets, F limits, and stable catch. We present the basic theory together with selected model variants, such as inclusion of biological interactions and integration of elements of risk assessment. The optimization procedure outlined here is not only “risk averse” but a risk minimization procedure in itself. It can be applied in a deterministic or stochastic decision-making process as well as within a single or multispecies context. We illustrate the approach with a simplified (deterministic) multispecies fisheries management and a (stochastic) single-species risk assessment example.
Phasercrystallographic software
Authors: McCoy Airlie J. , Grosse-Kunstleve Ralf W. , Adams Paul D. , Winn Martyn D. , Storoni Laurent C. , Read Randy J.
Published: July 2007

Phaseris a program for phasing macromolecular crystal structures by both molecular replacement and experimental phasing methods. The novel phasing algorithms implemented inPhaserhave been developed using maximum likelihood and multivariate statistics. For molecular replacement, the new algorithms have proved to be significantly better than traditional methods in discriminating correct solutions from noise, and for single-wavelength anomalous dispersion experimental phasing, the new algorithms, which account for correlations betweenF+andF−, give better phases (lower mean phase error with respect to the phases given by the refined structure) than those that use meanFand anomalous differences ΔF. One of the design concepts ofPhaserwas that it be capable of a high degree of automation. To this end,Phaser(written in C++) can be called directly from Python, although it can also be called using traditionalCCP4keyword-style input.Phaseris a platform for future development of improved phasing methods and their release, including source code, to the crystallographic community.
Identification of domains in protein crystal structures
Authors: Carugo Oliviero
Published: July 2007

Large proteins are often composed of two or more domains, the identification of which can allow one to determine their crystal structures at higher resolution. The computer program described here is intended to assist the user in the identification of the structural domains, defined as compact ensembles of residues, on the basis of the crystal structure of the protein that contains them.
Scattering from laterally heterogeneous vesicles. III. Reconciling past and present work
Authors: Pencer Jeremy , Anghel Vinicius N. P. , Kučerka Norbert , Katsaras John
Published: July 2007

A recent series of papers have devised and successfully used a methodology for the detection and characterization of domains in laterally heterogeneous vesiclesviasmall-angle neutron scattering. This methodology is in seeming contradiction to similar work devised by Knoll, Haas, Stuhrmann, Füldner, Vogel & Sackmann [J. Appl. Cryst.(1981),14, 191–202]. The present paper shows how these results may be reconciled.
Atomic displacements in BiFeO3 as a function of temperature: neutron diffraction study
Authors: Palewicz A. , Przeniosło R. , Sosnowska I. , Hewat A. W.
Published: July 2007

The parameters of the crystal structure of BiFeO3, described within the space group R3c, have been determined by high-resolution neutron powder diffraction for temperatures from 293 to 923 K. It was found that there is a local minimum for the rhombohedral angle αrh, near the Néel temperature T
N ≃ 640 K, a gradual rotation of the FeO6 octahedra and an increase of the Fe—O—Fe angle. The displacement of the Bi3+ ions from the FeO6 octahedra which influence the electric polarization decreases with temperature. One of the Bi—Fe distances also has a local maximum near T
N. The atomic vibrations of Bi3+ and O2− ions show a significant anisotropy.
Ligand and coordination-plane distortions in platinum(II) complexes of isomers of dimethyl-2,2′-bipyridine
Authors: Maheshwari Vidhi , Carlone Maria , Fronczek Frank R. , Marzilli Luigi G.
Published: July 2007

Pseudo-square-planar platinum(II) complexes containing 4,4′ (4,4′-Me2bipy), 5,5′ (5,5′-Me2bipy) and 6,6′ (6,6′-Me2bipy) isomers of dimethyl-2,2′-bipyridine (Me2bipy) were synthesized and structurally characterized to assess the effects of methyl-group position on structure. The Pt—N distances in (Me2bipy)PtCl2 complexes fall in the typical range [2.017 (3)–2.032 (3) Å]. Only minor distortions such as 2.4 and 5.5° twisting of the two pyridyl rings in (4,4′-Me2bipy)PtCl2 (I) and (5,5′-Me2bipy)PtCl2 (II), respectively, occur. However, (6,6′-Me2bipy)PtCl2 (III) is highly distorted: the two pyridyl rings in (III) have a large bowing angle (θB) of 19.2°. The presence of distortions in (III), but not in (I) and (II), is attributed to repulsions between the 6,6′-methyl groups and the cis chloro ligands. [(4,4′-Me2bipy)2Pt](BF4)2 (IV) undergoes a bow-incline deformation having a large θB value (24.2°), and the ligands are inclined relative to the coordination plane by 18.80 (13)°. Complex (IV) joins a small list of distorted bis-bipyridine complexes; this finding can be attributed to the unfavorable repulsions between the 6,6′ hydrogen substituents of opposing ligands. Some of these complexes exhibit canting rather than bow-incline distortion, a trend suggesting that subtle solid-state effects determine the nature of the distortion.
Chiral determination: direct interpretation of convergent-beam electron diffraction patterns using the series expansion of Cowley and Moodie
Authors: Johnson Andrew W. S.
Published: July 2007

Given a small number of structure factors of a known chiral structure of unknown hand, it is shown that the hand can be determined from the sign of the contrast difference of two reflections in a suitably oriented convergent-beam electron diffraction (CBED) pattern. A simple formula for this difference, which takes into account all the significant second-order scattering, is derived using the series expansion of Cowley and Moodie for n-beam diffraction. The reason for the success of a three-beam interpretation is investigated. The method is applied to patterns from thin crystals in which a mirror projection symmetry can be found and its validity is demonstrated by agreement with experiment using samples of known hand. The advantages of recording patterns near major zone axes are discussed as well as some other experimental aspects of chiral determination using CBED.
Porcelain—Raw Materials, Processing, Phase Evolution, and Mechanical Behavior
Authors: Carty William M. , Senapati Udayan
Published: July 2007

Porcelain represents the foundation of the ceramics discipline and one of the most complex ceramic materials. Composed primarily of clay, feldspar, and quartz, porcelains are heat‐treated to form a mixture of glass and crystalline phases. This review focuses on raw materials, processing, heat treatment, and mechanical behavior. Because of the complexities of the porcelain system and despite the substantial amount of research already conducted within the field, there remain significant opportunities for research and study, particularly in the areas of raw material understanding, processing science, and phase and microstructure evolution.
Where will species go? Incorporating new advances in climate modelling into projections of species distributions
Authors: BEAUMONT LINDA J. , PITMAN A. J. , POULSEN MICHAEL , HUGHES LESLEY
Published: July 2007

Bioclimatic models are the primary tools for simulating the impact of climate change on species distributions. Part of the uncertainty in the output of these models results from uncertainty in projections of future climates. To account for this, studies often simulate species responses to climates predicted by more than one climate model and/or emission scenario. One area of uncertainty, however, has remained unexplored: internal climate model variability. By running a single climate model multiple times, but each time perturbing the initial state of the model slightly, different but equally valid realizations of climate will be produced. In this paper, we identify how ongoing improvements in climate models can be used to provide guidance for impacts studies. In doing so we provide the first assessment of the extent to which this internal climate model variability generates uncertainty in projections of future species distributions, compared with variability between climate models. We obtained data on 13 realizations from three climate models (three from CSIRO Mark2 v3.0, four from GISS AOM, and six from MIROC v3.2) for two time periods: current (1985–1995) and future (2025–2035). Initially, we compared the simulated values for each climate variable (P, Tmax, Tmin, and Tmean) for the current period to observed climate data. This showed that climates simulated by realizations from the same climate model were more similar to each other than to realizations from other models. However, when projected into the future, these realizations followed different trajectories and the values of climate variables differed considerably within and among climate models. These had pronounced effects on the projected distributions of nine Australian butterfly species when modelled using the BIOCLIM component of DIVA‐GIS. Our results show that internal climate model variability can lead to substantial differences in the extent to which the future distributions of species are projected to change. These can be greater than differences resulting from between‐climate model variability. Further, different conclusions regarding the vulnerability of species to climate change can be reached due to internal model variability. Clearly, several climate models, each represented by multiple realizations, are required if we are to adequately capture the range of uncertainty associated with projecting species distributions in the future.
Dynamics of nitrous oxide in groundwater at the aquatic–terrestrial interface
Authors: CLOUGH TIM J. , ADDY KELLY , KELLOGG DOROTHY Q. , NOWICKI BARBARA L. , GOLD ARTHUR J. , GROFFMAN PETER M.
Published: July 2007

Few data are available to validate the Intergovernmental Panel on Climate Change's (IPCC) emission factors for indirect emissions of nitrous oxide (N2O). In particular the N2O emissions resulting from nitrogen leaching and the associated groundwater and surface drainage (EF5‐g) are particularly poorly characterized. In situ push–pull methods have been used to identify the fate of NO3− in the groundwater. In this study, we adapted a previously published in situ denitrification push–pull method to examine the fate of 15N2O introduced into the subsoil–groundwater matrix. Enriched 15N2O was manufactured, added to groundwater via a closed system in the laboratory, and then introduced into the groundwater–subsoil matrix in an upland‐marsh transition zone of a salt marsh and a forested alluvial riparian zone. Conservative tracers (SF6 and Br−) and 15N2O were injected into the groundwater and left for 1–4 h after which the groundwater was sampled. Added 15N2O behaved in a conservative manner at one site while the other site showed variability with some injections showing significant consumption (3–8 μg N2O‐15N kg−1 soil day−1) of 15N2O. Our results show that the fate and dynamics of N2O in groundwater are complex and variable and that these dynamics should be considered in the development of improved IPCC inventory calculations.
Ocean warming enhances respiration and carbon demand of coastal microbial plankton
Authors: VÁZQUEZ‐DOMÍNGUEZ EVARISTO , VAQUÉ DOLORS , GASOL JOSEP M.
Published: July 2007

The increase of anthropogenic CO2 during this century is expected to cause warming of large regions of the ocean. Microbes lead the biological role in the CO2 balance of marine ecosystems, their activity is known to be influenced by temperature, and it is important to constrain and quantify these effects on bacterial carbon use. Furthermore, if warming were to enhance the carbon demand (production + respiration) of planktonic microbes but would maintain their efficiency low (as it generally is), then most carbon consumed would end up respired. We designed a strategy in which we measured bacterial production and respiration throughout a seasonal cycle in a coastal Mediterranean site, and determined experimentally the effects of ca. 2.5 °C on these processes. We show that warming will increase nearly 20% the total carbon demand of coastal microbial plankton without any effect on their (commonly low) growth efficiency, which could generate a positive feedback between coastal warming and CO2 production.
Insects in a warmer world: ecological, physiological and life‐history responses of true bugs (Heteroptera) to climate change
Authors: MUSOLIN DMITRY L.
Published: July 2007

Focusing on the southern green stink bug, Nezara viridula (Pentatomidae), in central Japan the effects of climate change on true bugs (Insecta: Heteroptera) are reviewed. In the early 1960s, the northern edge of the species's distribution was in Wakayama Prefecture (34.1°N) and distribution was limited by the +5°C coldest month (January) mean temperature isothermal line. By 2000, N. viridula was recorded 70 km further north (in Osaka, 34.7°N). Historical climate data were used to reveal possible causes of the northward range expansion. The increase of mean and lowest winter month temperatures by 1–2°C in Osaka from the 1950s to the 1990s improved potential overwintering conditions for N. viridula. This promoted northward range expansion of the species. In Osaka, adult diapause in N. viridula is induced after mid‐September, much later than in other local seed‐feeding heteropterans. This late diapause induction results in late‐season ineffective reproduction: some females start oviposition in autumn when the progeny have no chance of attaining adulthood and surviving winter. Both reproductive adults and the progeny die. A period from mid‐September to early November represents a phenological mismatch: diapause is not yet induced in all adults, but it is already too late to start reproduction. Females that do not start reproduction but enter diapause in September have reduced postdiapause reproductive performance: they live for a shorter period, have a shorter period of oviposition and produce fewer eggs in smaller egg masses compared with females that emerge and enter diapause later in autumn. To some extent, N. viridula remains maladapted to Osaka environmental conditions. Ecological perspectives on establishment in recently colonized areas are discussed. A review of available data suggests that terrestrial and aquatic Heteroptera species respond to climate change by shifting their distribution ranges, changing abundance, phenology, voltinism, physiology, behaviour, and community structure. Expected responses of Heteroptera to further climate warming are discussed under scenarios of slight (<2°C) and substantial (>2°C) temperature increase.
Using functional groups to investigate community response to environmental changes: two grassland case studies
Authors: VOIGT WINFRIED , PERNER JÖRG , HEFIN JONES T.
Published: July 2007

Functional groups (FG) are an useful generalization to investigate environmental change effects on biotic communities. Assigning species to FGs is a contextual task and carries an arbitrary element, regardless of whether the grouping is obtained a priori or by sophisticated numerical methods. Using two grassland community case studies, we show that even simple FG allocation based on growth form, architecture and longevity (plants and mosses), or foraging characteristics (above‐ground invertebrates) can be useful to increase our understanding of community processes. For example, the sensitivity of organisms to climate change increases with trophic rank and is higher in disturbed than in undisturbed communities. Complexity of interaction webs (in terms of web connectance), however, is larger in undisturbed than in disturbed communities. A significant and important relationship is likely to exist between anthropogenic disturbances, community complexity and the ecosystem effects of climate change. Trophic interactions may be disrupted much easier by climate changes in disturbed than in undisturbed communities where complexity may be buffering these effects.
Predicting adaptation of phenology in response to climate change, an insect herbivore example
Authors: Van ASCH MARGRIET , Van TIENDEREN PETER H. , HOLLEMAN LEONARD J. M. , VISSER MARCEL E.
Published: July 2007

Climate change has led to an advance in phenology in many species. Synchrony in phenology between different species within a food chain may be disrupted if an increase in temperature affects the phenology of the different species differently, as is the case in the winter moth egg hatch–oak bud burst system. Operophtera brumata (winter moth) egg hatch date has advanced more than Quercus robur (pedunculate oak) bud burst date over the past two decades. Disrupted synchrony will lead to selection, and a response in phenology to this selection may lead to species genetically adapting to their changing environment. However, a prerequisite for such genetic change is that there is sufficient genetic variation and severe enough fitness consequences. So far, examples of observed genetic change have been few. Using a half‐sib design, we demonstrate here that O. brumata egg‐hatching reaction norm is heritable, and that genetic variation exists. Fitness consequences of even a few days difference between egg hatch and tree bud opening are severe, as we experimentally determined. Estimates of genetic variation and of fitness were then combined with a climate scenario to predict the rate and the amount of change in the eggs' response to temperature. We predict a rapid response to selection, leading to a restoration of synchrony of egg hatch with Q. robur bud opening. This study shows that in this case there is a clear potential to adapt – rapidly – to environmental change. The current observed asynchrony is therefore not due to a lack of genetic variation and at present it is unclear what is constraining O. brumata to adapt. This kind of model may be particularly useful in gaining insight in the predicted amount and rate of change due to environmental changes, given a certain genetic variation and selection pressure.
Dissecting the evolutionary impacts of plant invasions: bugs and beetles as native guides
Authors: CARROLL SCOTT P. , FOX CHARLES W.
Published: July 2007

The introduction of plants into new biogeographical realms is a main repercussion of human trade. The responses of native insects to alien plants may provide insight into how invaders influence ecological processes in their new communities. We illustrate this point with results from our field and lab studies of seed‐feeding insects on alien plants. Soapberry bugs (Jadera,Leptocoris) have colonized several species of weedy invasive plants (sapindaceous trees and vines) in the United States and Australia. After initial reduction in physiological performance, they evolved behavioral, morphological, physiological and life history adaptations permitting more efficient exploitation of those hosts. Those changes occurred quickly, in fewer than 100 generations (ca. 30–50 years). The underlying genetic changes are surprisingly complex, and also involve loss of function on native hosts. Contrasting with this is the bruchine beetle (Stator limbatus) on seeds of leguminous trees. Large numbers ofS. limbatusoviposit on an alien tree in Arizona, but few offspring survive. The main influence on larval survival is a maternal effect determined by the host the mother experiences as her eggs mature. Adaptive plasticity in egg size and composition may ultimately permit successful exploitation of novel resources. Together, these studies show that both complex genetic and developmental factors influence the integration of ecological and evolutionary processes in environments altered by anthropogenically initiated plant invasions. Tractable insect study systems may be valuable guides to understanding biotic dynamics in a changing world.
Management of obesity in primary care: nurses’ practices, beliefs and attitudes
Authors: Brown Ian , Stride Chris , Psarou Aikaterini , Brewins Louise , Thompson Joanne
Published: July 2007

Aim.  This paper is a report of a study to investigate patterns of clinical practice, beliefs and attitudes of primary care nurses with respect to obesity management.

Background.  Nurses in primary care potentially play a key role in managing obesity, which has become a priority issue. There have been few studies of either the extent of clinical practice of nurses, or their attitudes and beliefs in this setting.

Methods.  A correlational survey design was employed. Structured questionnaires were posted to 564 nurses and health visitors in primary care organizations in England. The response rate was 72·3%. The survey was conducted in April and May 2006.

Findings.  Very few respondents reported training in obesity management, and most did not believe that organizational support was in place. Only practice nurses reported substantial clinical activity in obesity management, accounting for almost 5% of their contracted hours. This activity, comprised of assessment, lifestyle change support and referral, occurred in one‐to‐one consultations. Other nurses and health visitors reported much less activity, although they believed obesity to be an important health issue and its management an appropriate part of their role. Whilst outright negative stereotypes were rare, there were nevertheless a range of potentially negative beliefs and attitudes relating to obesity and obese patients. These views were related to the respondent's own body mass index but not to gender, age, experience and occupation.

Conclusion.  Training and organizational support for obesity management are required by primary care nurses. Training should also address beliefs and attitudes about obesity and obese persons.
Association between complementary feeding practice and mothers education status in Islamabad
Authors: Liaqat P. , Rizvi M. A. , Qayyum A. , Ahmed H.
Published: July 2007

Objectives  To examine the association between mothers education, complementary feeding practices and malnutrition amongst mothers attending outpatient clinics in Islamabad.

Methods  Mothers of 500 Pakistani infants attending the Paediatric Outpatient department at the Federal Government Services Hospital, Islamabad completed pretested questionnaires on mother's educational status and complementary feeding practices.

Results  A positive relationship was found between the nutritional status of infants and educational status of mothers (P < 0.001). The study revealed that the majority of infants with evidence of malnutrition belonged to the mothers with virtually no school education. A similar relationship was observed between the educational status of respondents and the introduction of complementary foods at an appropriate age (6 months) of infants (P < 0.001).

Conclusion  Mother's education plays a vital role in increased receptivity to knowledge and awareness related to nutritional requirements of their infants.
The Mental Capacity Act 2005: implications for dietetic practice
Authors: Lyons C. , Brotherton A. , Stanley N. , Carrahar M. , Manthorpe J.
Published: July 2007

The Mental Capacity Act (MCA) 2005 will be implemented in England and Wales in 2007 and have consequences for dietitians who work with people who may lack capacity to make specific decisions. This paper will explore issues arising from the introduction of the Act and considers the implications for dietitians involved in the delivery of clinical care, using enteral feeding as an illustrative example.

If patients lack capacity to make specific decisions, dietitians will be required to record if, how and why they reached a decision, how they are involved in the decision making process and need to be able to justify their actions in relation to those decisions. This paper discusses the importance of dietitians’ involvement in best interests decision making and considers the implications of decision making where people have drawn up a Lasting Power of Attorney. The role of such advance decisions is discussed and consideration is given to the potential compatibility of perspectives between the patient and family that may give rise to disputes.

Dietitians may be well placed within multidisciplinary team working to ensure patients and their carers are part of the decision making process through effective communication and support for patients. Dietitians in England and Wales must consider the implications of the MCA upon their clinical practice and others outside these jurisdictions may like to reflect on the relevance of such developments in their own contexts.
Introduction history of Drosophila subobscura in the New World: a microsatellite‐based survey using ABC methods
Authors: PASCUAL M. , CHAPUIS M. P. , MESTRES F. , BALANYÀ J. , HUEY R. B. , GILCHRIST G. W. , SERRA L. , ESTOUP A.
Published: July 2007

Drosophila subobscura is a Palearctic species that was first observed in South and North America in the early 1980s, and that rapidly invaded broad latitudinal ranges on both continents. To trace the source and history of this invasion, we obtained genotypic data on nine microsatellite loci from two South American, two North American and five European populations of D. subobscura. We analysed these data with traditional statistics as well as with an approximate Bayesian computation (ABC) framework. ABC methods yielded the strongest support for the scenario involving a serial introduction with founder events from Europe into South America, and then from South America into North America. Stable effective population size of the source population was very large (around one million individuals), and the propagule size was notably smaller for the introduction into South America (i.e. high bottleneck severity index with only a few effective founders) but considerably larger for the subsequent introduction into North America (i.e. low bottleneck severity index with around 100–150 effective founders). Finally, the Mediterranean region of Europe (and most likely Barcelona from the localities so far analysed) is proposed as the source of the New World flies, based on mean individual assignment statistics.
Historical and ecological determinants of genetic structure in arctic canids
Authors: CARMICHAEL L. E. , KRIZAN J. , NAGY J. A. , FUGLEI E. , DUMOND M. , JOHNSON D. , VEITCH A. , BERTEAUX D. , STROBECK C.
Published: July 2007

Wolves (Canis lupus) and arctic foxes (Alopex lagopus) are the only canid species found throughout the mainland tundra and arctic islands of North America. Contrasting evolutionary histories, and the contemporary ecology of each species, have combined to produce their divergent population genetic characteristics. Arctic foxes are more variable than wolves, and both island and mainland fox populations possess similarly high microsatellite variation. These differences result from larger effective population sizes in arctic foxes, and the fact that, unlike wolves, foxes were not isolated in discrete refugia during the Pleistocene. Despite the large physical distances and distinct ecotypes represented, a single, panmictic population of arctic foxes was found which spans the Svalbard Archipelago and the North American range of the species. This pattern likely reflects both the absence of historical population bottlenecks and current, high levels of gene flow following frequent long‐distance foraging movements. In contrast, genetic structure in wolves correlates strongly to transitions in habitat type, and is probably determined by natal habitat‐biased dispersal. Nonrandom dispersal may be cued by relative levels of vegetation cover between tundra and forest habitats, but especially by wolf prey specialization on ungulate species of familiar type and behaviour (sedentary or migratory). Results presented here suggest that, through its influence on sea ice, vegetation, prey dynamics and distribution, continued arctic climate change may have effects as dramatic as those of the Pleistocene on the genetic structure of arctic canid species.
High quantitative and no molecular differentiation of a freshwater snail (Galba truncatula) between temporary and permanent water habitats
Authors: CHAPUIS ELODIE , TROUVE SANDRINE , FACON BENOIT , DEGEN LOÏC , GOUDET JEROME
Published: July 2007

We investigate the variation in quantitative and molecular traits in the freshwater snail Galba truncatula, from permanent and temporary water habitats. Using a common garden experiment, we measured 20 quantitative traits and molecular variation using seven microsatellites in 17 populations belonging to these two habitats. We estimated trait means in each habitat. We also estimated the distributions of overall genetic quantitative variation (QST), and of molecular variation (FST), within and between habitats. Overall, we observed a lack of association between molecular and quantitative variance. Among habitats, we found QST > FST, an indication of selection for different optima. Individuals from temporary water habitat matured older, at a larger size and were less fecund than individuals from permanent water habitat. We discuss these findings in the light of several theories for life‐history traits evolution.