bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimates of forest canopy height and aboveground biomass using ICESat
Authors: Lefsky Michael A. , Harding David J. , Keller Michael , Cohen Warren B. , Carabajal Claudia C. , Del Bom Espirito‐Santo Fernando , Hunter Maria O. , de Oliveira Raimundo
Published: October 2005

Exchange of carbon between forests and the atmosphere is a vital component of the global carbon cycle. Satellite laser altimetry has a unique capability for estimating forest canopy height, which has a direct and increasingly well understood relationship to aboveground carbon storage. While the Geoscience Laser Altimeter System (GLAS) onboard the Ice, Cloud and land Elevation Satellite (ICESat) has collected an unparalleled dataset of lidar waveforms over terrestrial targets, processing of ICESat data to estimate forest height is complicated by the pulse broadening associated with large‐footprint, waveform‐sampling lidar. We combined ICESat waveforms and ancillary topography from the Shuttle Radar Topography Mission to estimate maximum forest height in three ecosystems; tropical broadleaf forests in Brazil, temperate broadleaf forests in Tennessee, and temperate needleleaf forests in Oregon. Final models for each site explained between 59% and 68% of variance in field‐measured forest canopy height (RMSE between 4.85 and 12.66 m). In addition, ICESat‐derived heights for the Brazilian plots were correlated with field‐estimates of aboveground biomass (r2 = 73%, RMSE = 58.3 Mgha−1).
De‐coupling of net community production and new production in the euphotic zone of the equatorial Pacific: A model study
Authors: Wang Xiujun , Murtugudde Ragu , Busalacchi Antonio J. , Le Borgne Robert
Published: October 2005

A physical‐biogeochemical model is employed to estimate rates of nitrogen based primary production (PP*), net community production (NCP*), and new production (NP) in the equatorial Pacific. The model reproduces observed vertical differences between ammonium regeneration and uptake: uptake > regeneration above 40 m and uptake < regeneration below 40 m. As a result, NCP* exceeds NP in the upper 40 m, but decreases more rapidly with depth than NP. High surface NCP* appears across the entire upwelling region whereas high surface NP is found in the eastern equatorial Pacific with a much stronger spatial and temporal variability in NCP* relative to NP. The NCP*/PP* ratio shows a larger range (0.1–0.4) than the f‐ratio (i.e., the NP/PP* ratio) (0.1–0.3). The zonal and vertical de‐coupling between NCP* and NP is caused by the time lag between biological uptake and regeneration, and the advection of organic and inorganic nitrogen. The excess of NCP* over NP in the upper euphotic zone suggests the possibility of carbon over‐consumption in the upper ocean of the equatorial Pacific with implications for predicting sinks/sources of CO2.
Optimized transition-edge x-ray microcalorimeter with 2.4eV energy resolution at 5.9keV
Authors: Ullom J. N. , Beall J. A. , Doriese W. B. , Duncan W. D. , Ferreira L. , Hilton G. C. , Irwin K. D. , Reintsema C. D. , Vale L. R.
Published: October 2005

We present measurements from a series of transition-edge x-ray microcalorimeters designed for optimal energy resolution. We used the geometry of the sensors to control their heat capacity and employed additional normal metal features and a perpendicular magnetic field to control the sharpness of the superconducting-to-normal transition. These degrees of control allow an optimal selection of sensor saturation energy and noise. Successive design changes improved the measured energy resolution of the sensors from 4.5eV full width at half maximum at 5.9keVto2.4eV at 5.9keV. Sensors with this energy resolution are well matched to applications in x-ray astrophysics and terrestrial materials analysis.
On the control of surface waves by a vertical magnetic field
Authors: Sreenivasan Binod , Davidson Peter A. , Etay Jacqueline
Published: October 2005

We consider the magnetic damping of surface gravity waves by a vertical magnetic field. The damping mechanism is, in principle, quite simple. The motion of a conducting fluid in the presence of an imposed magnetic field leads to electric currents, and hence to Ohmic dissipation. As the fluid heats up, there is a corresponding loss in the mechanical energy of the wave motion. When the fluid is infinite in the horizontal plane, or else bounded by perfectly conducting vertical walls, the induced currents have a simple spatial distribution and so the analysis of such waves is straightforward [L. E. Franekel, J. Fluid. Mech. 7, 81 (1959); P. Rivat, J. Etay, and M. Garnier, Eur. J. Mech. B/Fluids 10, 537 (1991)]. However, in most practical applications of magnetic damping the fluid is bounded by nonconducting vertical walls. This leads to a complex distribution of electric currents and to a much weaker form of damping. In this paper, we extend the simple classical theory to accommodate nonconducting sidewalls, and show that the characteristic damping time increases by a factor of ∼30 due to the presence of these walls. Experiments are described for both conducting and insulating sidewalls. The results of the experiments are in good agreement with the theory.
Phonon-assisted ballistic to diffusive crossover in silicon nanowire transistors
Authors: Gilbert M. J. , Akis R. , Ferry D. K.
Published: October 2005

As transistors get smaller, the simulations require full quantum-mechanical treatments. Most such approaches have treated the transport as ballistic, ignoring the scattering that is known to occur in such devices. We present the results of a three-dimensional, self-consistent quantum simulation of a silicon nanowire transistor. In these simulations we have included phonon scattering through a real-space self-energy assuming weak interactions. In these silicon nanowire transistors, the ballistic to diffusive crossover occurs at much smaller distances than previously anticipated.
Textured Ca3Co4O9 thermoelectric oxides by thermoforging process
Authors: Prevel M. , Lemonnier S. , Klein Y. , Hébert S. , Chateigner D. , Ouladdiaf B. , Noudem J. G.
Published: October 2005

Using thermoforging process, dense Ca3Co4O9 (Co349) thermoelectric oxides have been successfully textured. The various parameters influencing the formation of the Co349-textured material have been investigated. The electrical transport measurements show an anisotropy of the resistivity in good agreement with scanning electron microscopy observations. Texture is quantified by neutron-diffraction measurements and correlated to anisotropic resistivity measurements and Seebeck coefficients.
Pulsed laser annealing of Be-implanted GaN
Authors: Wang H. T. , Tan L. S. , Chor E. F.
Published: October 2005

Postimplantation thermal processing of Be in molecular-beam-epitaxy-grown GaN by rapid thermal annealing (RTA) and pulsed laser annealing (PLA) was investigated. It has been found that the activation of Be dopants and the repair of implantation-induced defects in GaN films cannot be achieved efficiently by conventional RTA alone. On the other hand, good dopant activation and surface morphology and quality were obtained when the Be-implanted GaN film was annealed by PLA with a 248nm KrF excimer laser. However, observations of off-resonant micro-Raman and high-resolution x-ray-diffraction spectra indicated that crystal defects and strain resulting from Be implantation were still existent after PLA, which probably degraded the carrier mobility and limited the activation efficiency to some extent. This can be attributed to the shallow penetration depth of the 248nm laser in GaN, which only repaired the crystal defects in a thin near-surface layer, while the deeper defects were not annealed out well. This situation was significantly improved when the Be-implanted GaN was subjected to a combined process of PLA followed by RTA, which produced good activation of the dopants, good surface morphology, and repaired bulk and surface defects well.
Fabrication of one-dimensional GaAs channel-coupled InAs quantum dot memory device by selective-area metal-organic vapor phase epitaxy
Authors: Nataraj Devaraj , Ooike Noboru , Motohisa Junichi , Fukui Takashi
Published: October 2005

Narrow wirelike openings were defined on SiO2-masked GaAs (001) substrates by electron-beam lithography and wet chemical etching methods. A one-dimensional GaAs channel-coupled InAs quantum dot memory device was fabricated in this opened area by the selective-area metal-organic vapor phase epitaxy. Drain current measurement by sweeping the gate voltage forward and backward showed clear hysteresis up to 180K due to electrons charging into the quantum dots with a threshold voltage difference (ΔVth) of 165mV at 20K and 29mV at 180K. Comparison of experimental ΔVth values with the theoretically calculated ones showed that around 300 and 50 electrons were responsible for the memory operation at 20 and 180K, respectively. Real time measurements showed that the write/erase states of the memory device were discriminated for more than 5min at 20K and about 100s at 77K.
Characteristics of lead zirconate titanate ferroelectric thick films from a screen-printing laser transfer method
Authors: Xu Baomin , White David , Zesch James , Rodkin Alexandra , Buhler Steve , Fitch John , Littau Karl
Published: October 2005

Microstructures and electrical properties of lead zirconate titanate (PZT) thick films made by using a screen-printing laser transfer method have been studied. The PZT thick-film elements were first screen printed on a sapphire substrate and sintered at 1150to1250°C. Then they were bonded to a target substrate such as silicon and released from the sapphire by means of an excimer laser exposure from the backside of the sapphire substrate. This approach makes it possible to obtain highly densified films because there is less limitation on sintering conditions, and allows integrating patterned PZT thick films onto many kinds of substrates. The thick films have dielectric constants of 1397 to 1675, remnant polarization of 32to35μC∕cm2, a piezoelectric constant d31 of about −124pm∕V, and Young’s modulus Y11E(59.4GPa) of almost the same as the corresponding bulk ceramic.
Solid-solid phase transformation via internal stress-induced virtual melting: Additional confirmations
Authors: Levitas Valery I. , Smilowitz Laura B. , Henson Bryan F. , Asay Blaine W.
Published: October 2005

Recently, we predicted a mechanism of solid-solid phase transformation (PT) via virtual melting at 121K below the melting temperature. We report additional experimental and theoretical results for PTs among three polymorphs of the energetic material HMX, α, β, and δ that support this mechanism. In particular: (a) the predicted velocity of interface propagation for β→δ PT and overall kinetics of δ→β PT are in agreement with experiment; (b) the energy of internal stresses is sufficient to reduce the melting temperature from 520to400K for δ→β PT; (c) the nanocracking that appears during solidification does not change the PT thermodynamics and kinetics for the first and the second β↔δ PT cycles; (d) δ→β PT starts at a very small driving force; (e) δ→α and α→δ PTs do not occur above 400K and below 461K, respectively.
Achieving superresolution in near-field optical data readout systems using surface plasmons
Authors: Gbur Greg , Schouten Hugo F. , Visser Taco D.
Published: October 2005

The effects of surface plasmons and enhanced transmission on the readout contrast in a superresolving near-field optical data system are studied numerically using an exact Green’s tensor formulation. It is shown that plasmon effects can both help and hinder such a readout system, and the system geometry must be chosen carefully to produce optimal effects. Under certain conditions, the system can have a readout contrast approaching 50% and a resolution of at least λ∕3.
Radiation of spin waves from magnetic vortex cores by their dynamic motion and annihilation processes
Authors: Lee Ki-Suk , Choi SangKook , Kim Sang-Koog
Published: October 2005

We report on micromagnetic simulation results of radiation of strong spin waves from the cores of magnetic vortices driven by their dynamics motion or the annihilation of a vortex-antivortex pair in a rectangular shaped magnetic thin film. Such strong spin-waves are distinguished from spin wave modes typically excited in patterned magnetic elements. The spin wave excitation with relatively low frequencies of 0–22 GHz are associated with the shape of an element, a magnetization configuration, and an applied magnetic field, while dominating spin waves in the higher frequencies of 22–96 GHz are driven by either the motion or annihilation of vortex cores present in the confined element. The latter case yields much higher amplitudes than the former does. It is found that large torques applied at the local area of the vortex cores, driven by the large exchange fields in the core region during their dynamic motion and collapse, induce a rapid energy dissipation into the surrounding areas through the spin-wave excitation and subsequent propagation. In addition, it is found that the strong spin waves radiated by the dynamic evolution processes of the vortex cores propagate well into a long stripe-shaped magnetic wire. Such traveling spin waves can be applicable for a new generation of magnetic logic devices.
The International Labour Standards Regime: A Case Study in Global Regulation
Authors: Haworth Nigel , Hughes Stephen , Wilkinson Rorden
Published: October 2005

The World Trade Organisation's (WTO) consistent rejection of proposals for the inclusion of a social clause into its existing rules and regulations has prompted the International Labour Organisation (ILO) to examine alternative ways in which global consensus on the regulation of labour standards can be developed. In this paper we map the failure of the social clause debate by reference to the outcome of successive WTO ministerials and we examine the role of executive leadership and related epistemic activity in the development of the international labour standards regime (ILSR). We conclude that the switch to a focus on a regime of core labour standards provides the most promising platform for progress in labour protection and an influential outcome in placing the ILO at the heart of attempts to integrate social policy into global economic governance.
Global Standards and the Environmental Performance of Industry
Authors: Angel David P , Rock Michael T
Published: October 2005

In this paper we examine the emergence of firm-based global environmental standards as an approach to managing the environmental performance of complex global production networks. Firm-based global environmental standards exist when a firm defines a uniform set of process and product environmental performance requirements that must be adhered to by all of a firm's facilities around the world, even if these firm-based standards exceed the requirements of local and national environmental regulations. We identify increasingly stringent end-market environmental regulation, as well as growing concern over the need to protect a firm's reputational capital and operating legitimacy, as two key drivers of the adoption of firm-based environmental standards. Our analysis suggests, however, that firms are responding to these external drivers in part because of the characteristics of global production networks—a production form that depends on the ability to produce from any manufacturing plant to any end market. The paper examines the impact of firm-based environmental standards through case studies of a cement plant in Thailand and an electronics manufacturing plant in Penang, Malaysia. In line with the literature on new institution economics, the case studies demonstrate that firm-based standards are providing a platform for learning and innovation within the firm.
Regulatory Capture in the Globalisation of Accounting Standards
Authors: Godfrey Jayne M , Langfield-Smith Ian A
Published: October 2005

The Australian Financial Reporting Council recently shocked the world business community by unexpectedly announcing a change in the nation's approach to global-accounting-standards development. The change involved switching from ensuring consistency of Australian accounting standards with International Financial Reporting Standards (IFRSs) developed by the International Accounting Standards Board to outright adoption of IFRSs by 2005. At the time of the announcement, Australia had the most developed international harmonisation programme of any country with a well-developed financial reporting system. Events surrounding the change demonstrate how political the accounting standard-setting process can be as it continues to receive front-page media attention, and as it provides a platform in parliamentary and electoral debate. In the meantime, the US role in the global accounting standard-setting arena has moved through phases of indifference to potential active dominance, and European influences have waxed and waned. We examine whether swings in political and regulatory influences that occur when globalisation becomes a national and international goal are explained by regulatory capture theory. We also address the extent to which a subset of a single nation's regulatory system plays a key role in a series of larger national and international games. Drawing upon experiences in Australia, the United States, and the European Union, we identify political influences on initiatives to reform accounting-standard-setting environments, policies, and processes.
Is the Future ‘Regional’ for Global Standards?
Authors: Thompson Grahame F
Published: October 2005

The paper concerns the formation of standard setting in respect to international economic activity. A number of different forms of standard setting are discussed, but the analysis is concentrated upon the macro context for this process. In this paper I review the issue of the convergence in institutional design and systemic patterns of economic activity as global standards are pressed onto the governance framework for international economic management. However, the analysis suggests that the international economy is developing along a distinct path towards supranational regional bloc formations rather than towards an ever more global pattern. The consequences of this shaping of the international economy for the processes of standard setting in a number of different contexts are discussed.
Why Should They Care? The Role of Institutional Investors in the Market for Corporate Global Responsibility
Authors: Clark Gordon L , Hebb Tessa
Published: October 2005

Institutional investors, primarily pension funds, drive global financial markets. The result is investors vulnerable to the risks companies face in global consumer and capital markets. Though some market risks are inevitable, others, such as reputation risk, can be mitigated through increased corporate social and environmental standards and the increased transparency that such higher standards demand. The transparency necessitated by reputation management has a dual role in monitoring corporate behaviour and providing all stakeholders (internal and external) with the information to evaluate corporate behaviour. Driving this process is the belief that higher standards of corporate responsibility pay off for investors over the long term both through potential equity premia and through risk reduction. This paper presents a model for understanding how and why institutional investors may encourage firms to adopt higher standards. To illustrate our argument, we refer to the experience of the UK Universities Superannuation Scheme (USS) strategy of corporate engagement and the attempts of the USS to encourage firms to raise their environmental standards by focusing on the climate change impacts of pension-fund investments. Investor engagement in corporate responsibility offers an insight into the role of investors in global-standard setting and global citizenship.
Ovaries Remain Functional in Squirrel Monkeys (Saimiri sciureus) Immunized with Porcine Zona Pellucida 55,000 Macromolecule1
Authors: Sacco Anthony G. , Pierce Donna L. , Subramanian Marappa G. , Yurewicz Edward C. , Richard Dukelow W.
Published: October 2005

Fifty female squirrel monkeys were each immunized with 200 micrograms of a purified preparation of the 55,000 macromolecule (ZP3) from porcine zona pellucida. The fertility status of these immunized monkeys, as well as the effect of ZP3 antibodies on ovarian function, was monitored. High anti-ZP3 titers were achieved (> 75% binding levels as determined by radioimmunoassay) and remained high (~ 67% binding level) for the duration of this study. Hormonal evaluations indicated initial disturbances in normal ovarian steroid secretion and function that were confirmed by laparoscopic observation and oocyte production data. Histological examination of ovaries at 6–7 mo post-injection suggested an interference in folliculogenesis. No pregnancies were observed in the immunized monkeys during this period. By 10–15 mo post-immunization, hormonal and laparoscopic data indicated that ovarian function was recovering in injected monkeys despite the continued presence of high titers to ZP3. Collectively, these results demonstrate that although immunization with ZP3 initially produces disturbances in normal ovarian function that inhibit fertility, these effects are reversible. Such findings encourage the continued intensive investigation of purified porcine zona macromolecules for immunocontraceptive purposes.
High dose factor VIIa improves clot structure and stability in a model of haemophilia B
Authors: Wolberg Alisa S. , Allen Geoffrey A. , Monroe Dougald M. , Hedner Ulla , Roberts Harold R. , Hoffman Maureane
Published: October 2005

Factor IX (FIX) deficiency results in haemophilia B and high dose recombinant activated factor VII (rFVIIa) can decrease bleeding. Previously, we showed that FIX deficiency results in a reduced rate and peak of thrombin generation. We have now used plasma and anin vitrocoagulation model to examine the effect of these changes in thrombin generation on fibrin clot structure and stability. Low FIX delayed the clot formation onset and reduced the fibrin polymerisation rate. Clots formed without FIX were composed of thicker fibrin fibres than normal. rFVIIa shortened the clot formation onset time and improved the fibre structure of haemophilic clots. We also examined clot formation in the presence of a fibrinolytic challenge by including tissue plasminogen activator or plasmin in the reaction milieu. In these assays, normal FIX levels supported clot formation; however, clots did not form in the absence of FIX. rFVIIa partially restored haemophilic clot formation. These results were independent of the effects of the thrombin‐activatable fibrinolysis inhibitor. Our data suggest that rFVIIa enhances haemostasis in haemophiliacs by increasing the thrombin generation rate to both promote formation of a structurally normal clot and improve clot formation and stability at sites with high endogenous fibrinolytic activities.
Population dynamics, growth and production of Sigara selecta (Fieber, 1848) (Hemiptera, Corixidae) in a Mediterranean hypersaline stream
Authors: BARAHONA J. , MILLAN A. , VELASCO J.
Published: October 2005

1. This is the first study on the life cycle, growth and production of Sigara selecta, a Palearctic corixid species typical of brackish and saline waters, at the warmest limit of its European distributional range. The study combines field and laboratory approaches.

2. The S. selecta population studied was multivoltine, producing four asynchronous cohorts from early spring to December and overwintering in the adult state. Development time from egg to first adult ranged from 2 to 3 months. A minimum temperature threshold of 10 °C and diel amplitude of ≥10 °C were observed for reproduction and oviposition.

3. Maximum density and biomass were reached in mid spring and early autumn. The sex ratio was unbalanced, females dominating during most of the year, except in spring, when the sex ratio was balanced or dominated by males during the first adult emergence.

4. Laboratory rearing experiments at constant temperatures (18, 22 and 26 °C) pointed to a significant effect of temperature on egg development and nymphal growth. In the range of temperatures tested, both egg and nymphal instar duration decreased with increasing temperature. Mean nymphal development time varied from 43 days at 26 °C to 71 days at 18 °C, with a mean of 57 days. Survivorship was independent of temperature.

5. A reduction in nymphal and adult length was observed with increasing temperature.

6. Growth rates decreased with increasing body mass and increased as temperature increased. The first nymphal instar had the highest length increments and growth rates in all temperature treatments.

7. Satisfactory agreement was found between the field and laboratory degree‐days required for complete development from egg to first adult. At constant and variable thermal regimes, degree‐days decreased with increasing temperature.

8. Rate of growth in the field could be predicted with reasonable accuracy from a simple model obtained as a function of body mass. The model explained 67% of the variability in growth rates.

9. Annual production and production/biomass ratio (P/B) of S. selecta estimated by the Instantaneous Growth method were 1.28 g m−2 year−1 and 13.71, respectively. Spring and autumn cohorts contributed 32% and 54%, respectively, of total annual production. Maximum production corresponded to intermediate temperature periods, although summer production may have been underestimated because of the longer sampling interval relative to cohort interval production. The Size Frequency method underestimated production by at least 18% with respect to the Instantaneous Growth method.
Assessing the patterns and controls of fine root dynamics: an empirical test and methodological review
Authors: HENDRICKS JOSEPH J. , HENDRICK RONALD L. , WILSON CARLOS A. , MITCHELL ROBERT J. , PECOT STEPHEN D. , GUO DALI
Published: October 2005

Elucidation of the patterns and controls of forest net primary production at ecosystem scales has been hindered by a poor understanding of fine root production, due largely to technical limitations.

Fine root (≤ 0.5 mm diameter) production was assessed using minirhizotron, soil core, ingrowth core, nitrogen budget and carbon budget techniques in three longleaf pine‐wiregrass forest ecosystem types (hydric, mesic and xeric) forming an edaphic resource availability and above‐ground productivity gradient.

Fine root production estimates differed substantially in magnitude, e.g. values ranged from 0 to 4618 kg ha−1 year−1for the soil core and minirhizotron techniques, respectively, in the hydric site.

Minirhizotron production estimates in the hydric, mesic and xeric sites were 4618, 1905 and 2295 kg ha−1 year−1, respectively.

Soil core and ingrowth core root production estimates were on average 81 and 54% lower, respectively, than corresponding minirhizotron production estimates, and minirhizotron estimates were negatively related to soil core and ingrowth core estimates across the resource gradient.

The N budget method yielded unreliable root production estimates, presumably due to the underestimation of N availability for plant assimilation.

C budget estimates of total below‐ground C allocation (6773, 5646 and 4647 kg C ha−1year−1) were positively related to minirhizotron production estimates, but negatively related to soil core and ingrowth core production estimates.

Critical evaluations of the assumptions, potential errors and results for each method suggest that the minirhizotron technique yielded the most reliable root production estimates, and that the negative relationship between minirhizotron and core‐based estimates may be attributed to the inherent deficiency of the core techniques in assessing root production when mortality and production occur simultaneously.

Minirhizotron root production estimates were positively related to foliage production estimates, supporting the hypothesis of constant proportional allocation of production to foliage, wood and fine roots across resource availability gradients in temperate forests.

These results suggest that fine root production is not negatively correlated with soil resource availability and foliage production as is commonly perceived in the ecological community and represented in ecosystem computer models.
Changes in Hypothalamic‐Pituitary‐Adrenal Function, Body Temperature, Body Weight and Food Intake with Repeated Social Stress Exposure in Rats
Authors: Bhatnagar S. , Vining C. , Iyer V. , Kinni V.
Published: October 2005

These present studies aimed to compare changes in hypothalamic‐pituitary‐adrenal (HPA) activity and body temperature in response to acute social defeat, to repeated social stress and to novel restraint after repeated stress, as well as to assess effects on metabolic parameters by measuring body weight gain and food and water intake. We found that social defeat produced a marked increase in both adrenocorticotrophic hormone and corticosterone compared to placement in a novel cage. Similarly, body temperature was also increased during social defeat and during 30 min of recovery from defeat. We then examined the effects of 6 days of repeated social stress and observed minimal HPA responses to repeated social stress compared to control rats. These neuroendocrine responses were contrasted by robust increases in body temperature during stress and during recovery from stress during 6 days of repeated stress. However, in response to novel restraint, repeatedly stressed rats displayed facilitated body temperature responses compared to controls, similar to our previous findings with HPA activity. Food intake was increased during the light period during which defeat took place, but later intake during the dark period was not affected. Repeated stress decreased body weight gain in the dark period but food intake was increased overall during the 6 days of repeated stress in the light period. As a result, repeated stress increased cumulative food intake during the light period in the stressed rats but these relatively small increases in food intake were unable to prevent the diminished total weight gain in repeatedly stressed rats. Overall, the results demonstrate that, although acute social defeat has similar effects on temperature and HPA activity, repeated exposure to social stress has divergent effects on HPA activity compared to body temperature and that dampened weight gain produced by repeated social stress cannot be fully explained by changes in food intake.
Influence of Oestrogenic Compounds on Monoamine Transporters in Rat Striatum
Authors: Le Saux M. , Di Paolo T.
Published: October 2005

Oestrogens have been reported to modulate rat membrane (DAT) and vesicular (VMAT2) dopamine transporters. A recent pilot study of postmenopausal women showed that chronic oestrogen replacement therapy increases striatal DAT. In the present study, we first investigated whether the oestrogen receptors α and β mediate the effects of oestradiol on DAT and VMAT2. Two days after ovariectomy, Sprague‐Dawley rats were treated for 2 weeks with oestradiol or specific ligands for oestrogen receptor α, 4,4′,4′′‐(4‐propyl‐[1H]‐pyrazole‐1,3,5‐triyl)trisphenol (PPT) or oestrogen receptor β, 2,3‐bis(4‐hydroxyphenyl)‐propionitrile (DPN). Ovariectomy caused a decrease in [125I]‐3β‐(4‐iodophenyl)‐tropane‐2β‐carboxylic acid isopropyl ester ([125I] RTI‐121) specific binding to DAT transporters in the middle striatum compared to values for intact rats, and this was reversed by oestradiol replacement therapy. DPN, but not PPT, mimicked the effect of oestradiol. [125I] RTI‐121 specific binding in the anterior and posterior striatum was not affected by ovariectomy or any of the drug treatments. Second, we investigated whether oestradiol increased DAT specific binding after a longer period of hormonal withdrawal (a model of hormonal withdrawal at menopause) and whether the selective oestrogen receptor modulators (SERMs), tamoxifen and raloxifene, could reproduce the oestradiol‐induced increase of [125I] RTI‐121 specific binding in long‐term ovariectomised rats. Four months after ovariectomy, Sprague‐Dawley rats were treated for 2 weeks with oestradiol, tamoxifen or raloxifene, and then killed. Ovariectomy decreased [3H] RTI‐121 specific binding to DAT transporters in the middle striatum compared to values for intact rats. Treatment with oestradiol, tamoxifen and raloxifene reversed this effect. [125I] RTI‐121 specific binding in anterior and posterior striatum was not affected by ovariectomy or treatment with oestrogen receptor ligands. In both experiments, neither ovariectomy nor the oestrogenic treatments modulated striatal [3H] tetrahydrobenazine specific binding to VMAT2. Overall, these results suggest that oestrogen receptor β mediates the oestradiol‐induced increase of striatal DAT and that oestradiol can increase DAT density even after long‐term steroid withdrawal. The results also support the premise that the SERMs tamoxifen and raloxifene exert oestrogenic agonist effects in the brain.
Cold shock and cold tolerance in larvae and pupae of the blow fly, Lucilia sericata
Authors: Pitts K. M. , Wall R.
Published: October 2005

Abstract.  Understanding the effects of low winter temperatures on mortality is essential in the development of a full understanding of the long‐term population dynamics of any insect. The present study aims to examine the survival of pupae and larvae of the blow fly, Lucilia sericata, at overwintering temperatures. Groups of pupae and diapausing and nondiapausing third‐stage larvae of L. sericata are maintained in cooled incubators at either 3 °C and 6 °C. Groups are removed from the incubators at 3–4‐day intervals and transferred either to−8 °C or to 25 °C. After 1 h in the freezer, the larvae and pupae exposed to this cold‐shock are also transferred to 25 °C. Larvae and pupae are then allowed to continue development and the number of adults emerging from each group is counted. The results demonstrate that survival decreases linearly with the period of exposure at both 3 °C and 6 °C. Mortality is higher at 3 °C than at 6 °C and, in groups that receive the cold shock, cold‐shock reduces emergence by over 50%. However, there is no consistent tendency for diapausing larvae to survive prolonged cold or cold shock better than other life‐cycle stages. The results suggest that the facultative development of an overwintering diapause stage in L. sericata does not appear to be an adaptation to enhance cold tolerance or resistance to cold shock. It is concluded that the survival of overwintering L. sericata is likely to be relatively less affected by low temperatures than it is by, for example, biotic factors, particularly given the buffered soil environment and short time‐scales over which periods of cold act.
Molecular identification, heterologous expression and properties of light‐insensitive plant catalases
Authors: ENGEL NICOLE , SCHMIDT MATTHIAS , LÜTZ CORNELIUS , FEIERABEND JÜRGEN
Published: October 2005

Most catalases are inactivated by light in a heme‐sensitized and O2‐dependent reaction. In leaves of the alpine plant Homogyne alpina and in the peroxisomal cores of Helianthus annuus, light‐insensitive catalases were observed. For the catalases Hacat1 of H. alpina and HnncatA3 of H. annuus, cDNA clones were obtained. Expression of recombinant active enzymes in insect cells confirmed that they coded for light‐insensitive catalases. Kinetic and catalytic properties of light‐sensitive or light‐insensitive catalases did not differ substantially. However, the specific activity of the latter was markedly lower. The light‐insensitive catalase HaCAT‐1 was not resistant against inactivation by superoxide. Amino acid sequences of the light‐insensitive catalases HaCAT‐1 and HNNCATA3 were highly identical. They showed only a few exceptional amino acid substitutions at positions that are highly conserved in other catalases. These appeared to be localized mainly in a surface cavity at the entrance of a minor channel leading to the central heme, suggesting that this region played some, though yet undefined, role for light sensitivity. While the replacement of a highly conserved His by Thr225 was the most unique substitution, a single exchange of His225 by Thr in the light‐sensitive catalase SaCAT‐1 by mutagenesis was not sufficient to reduce its sensitivity to photoinactivation.
gid1, a gibberellin‐insensitive dwarf mutant, shows altered regulation of probenazole‐inducible protein (PBZ1) in response to cold stress and pathogen attack
Authors: TANAKA NAOKI , MATSUOKA MAKOTO , KITANO HIDEMI , ASANO TAKAYUKI , KAKU HISATOSHI , KOMATSU SETSUKO
Published: October 2005

A recessive gibberellin (GA)‐insensitive dwarf mutant of rice, gibberellin‐insensitive dwarf1 (gid1), has been identified, which shows a severe dwarf phenotype and contains high concentrations of endogenous GA. To elucidate the function of gid1, proteins regulated downstream of gid1 were analysed using a proteomic approach. Proteins extracted from suspension‐cultured cells of gid1 and its wild type were separated by two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE). Of a total of 962 proteins identified from the suspension‐cultured cells, 16 were increased and 14 were decreased in gid1 compared with its wild type. Among the proteins hyper‐accumulated in gid1 were osmotin, triosephosphate isomerase, probenazole inducible protein (PBZ1) and pathogenesis‐related protein 10. Of these four genes, only the expression of PBZ1 was increased by exogenous GA3 application. Expression of this gene was also enhanced in shoots of the wild type by cold stress or by rice blast fungus infection. Under normal growth conditions, there was more PBZ1 protein in gid1 than in the wild type. In addition, gid1 showed increased tolerance to cold stress and resistance to blast fungus infection. The ent‐copalyl diphosphate synthase (OsCPS) genes, which encode enzymes at the branch point between GA and phytoalexin biosynthesis, were expressed differentially in gid1 relative to the wild type. Specifically, OsCPS1, which encodes an enzyme in the GA biosynthesis pathway, was down‐regulated and OsCPS2 and OsCPS4, which encode enzymes in phytoalexin biosynthesis, were up‐regulated in gid1. These results suggest that the expression of PBZ1 is regulated by GA signalling and stress stimuli, and that gid1 is involved in tolerance to cold stress and resistance to blast fungus.
Reactivation of deep faults beneath Southern Apennines: evidence from the 1990–1991 Potenza seismic sequences
Authors: Di Luccio F. , Piscini A. , Pino N. A. , Ventura G.
Published: October 2005

We relocate the 1990–1991 Potenza (Southern Apennines belt, Italy) sequences and calculate focal mechanisms. This seismicity clusters along an E–W, dextral strike–slip structure. Second‐order clusters are also present and reflect the activation of minor shears. The depth distribution of earthquakes evidences a peak between 14 and 20 km, within the basement of the subducting Apulian plate. The analysed seismicity does not mirror that of Southern Apennines, which include NW–SE striking normal faults and earthquakes concentrated within the first 15 km of the crust. We suggest that the E–W faults affecting the foreland region of Apennine propagate up to 25 km of depth. The Potenza earthquakes reflect the reactivation of a deep, preexisting fault system. We conclude that the seismotectonic setting of Apennines is characterized by NW–SE normal faults affecting the upper 15 km of the crust, and by E–W deeper strike–slip faults cutting the crystalline basement of the chain.
Ornaments or offspring? Female sticklebacks (Gasterosteus aculeatus L.) trade off carotenoids between spines and eggs
Authors: Nordeide J. T. , Rudolfsen G. , Egeland E. S.
Published: October 2005

Hypotheses and models to explain female ornaments often assume that the elaborated traits are condition dependent; nevertheless, few empirical studies have addressed this topic. We studied a population of three-spined sticklebacks (Gasterosteus aculeatus) in which the females have conspicuous, carotenoid-based red coloration to their pelvic spines. The red coloration seems not to be condition dependent, as coloration is negatively associated with age and body length and not associated with condition. Furthermore, redder females did not have a lower density of leucocytes. We found a negative association between the females’ red carotenoid-based coloration in the spines and the amount of carotenoids in the female's gonads. Males choosing red-coloured females will fertilize eggs with small amounts of carotenoids and appear not to gain any benefit from their mates’ phenotypic quality that could result in offspring of improved quality. These results do not support the ‘direct selection hypothesis’ to explain the existence of the female ornaments.
Ecological specialization correlates with genotypic differentiation in sympatric host-populations of the pea aphid
Authors: Frantz A. , Plantegenest M. , Mieuzet L. , Simon J.-C.
Published: October 2005

The pea aphid, Acyrthosiphon pisum, encompasses distinct host races specialized on various Fabaceae species, but the extent of genetic divergence associated with ecological specialization varies greatly depending on plant and geographic origins of aphid populations. Here, we studied the genetic structure of French sympatric pea aphid populations collected on perennial (pea and faba bean) and annual (alfalfa and red clover) hosts using 14 microsatellite loci. Classical and Bayesian population genetics analyses consistently identified genetic clusters mostly related to plant origin: the pea/faba bean cluster was highly divergent from the red clover and the alfalfa ones, indicating they represent different stages along the continuum of genetic differentiation. Some genotypes were assigned to a cluster differing from the one expected from their plant origin while others exhibited intermediate genetic characteristics. These results suggest incomplete barriers to gene flow. However, this limited gene flow seems insufficient to prevent ecological specialization and genetic differentiation in sympatry.
Cannabinoid receptors in invertebrates
Authors: Mcpartland J. M. , Agraval J. , Gleeson D. , Heasman K. , Glass M.
Published: October 2005

Two cannabinoid receptors, CB1 and CB2, are expressed in mammals, birds, reptiles, and fish. The presence of cannabinoid receptors in invertebrates has been controversial, due to conflicting evidence. We conducted a systematic review of the literature, using expanded search parameters. Evidence presented in the literature varied in validity, ranging from crude in vivo behavioural assays to robust in silico ortholog discovery. No research existed for several clades of invertebrates; we therefore tested for cannabinoid receptors in seven representative species, using tritiated ligand binding assays with [3H]CP55,940 displaced by the CB1-selective antagonist SR141716A. Specific binding of [3H]CP55,940 was found in neural membranes of Ciona intestinalis (Deuterstoma, a positive control), Lumbricusterrestris (Lophotrochozoa), and three ecdysozoans: Peripatoides novae-zealandiae (Onychophora), Jasus edwardi (Crustacea) and Panagrellus redivivus (Nematoda); the potency of displacement by SR141716A was comparable to measurements on rat cerebellum. No specific binding was observed in Actinothoe albocincta (Cnidaria) or Tethya aurantium (Porifera). The phylogenetic distribution of cannabinoid receptors may address taxonomic questions; previous studies suggested that the loss of CB1 was a synapomorphy shared by ecdysozoans. Our discovery of cannabinoid receptors in some nematodes, onychophorans, and crustaceans does not contradict the Ecdysozoa hypothesis, but gives it no support. We hypothesize that cannabinoid receptors evolved in the last common ancestor of bilaterians, with secondary loss occurring in insects and other clades. Conflicting data regarding Cnidarians precludes hypotheses regarding the last common ancestor of eumetazoans. No cannabinoid receptors are expressed in sponges, which probably diverged before the origin of the eumetazoan ancestor.
Differential effects of egg albumen content on barn swallow nestlings in relation to hatch order
Authors: Ferrari R. P. , Martinelli R. , Saino N.
Published: October 2005

In diverse animal taxa, egg mass variation mediates maternal effects with long-term consequences for offspring ontogeny and fitness. Patterns of egg mass variation with laying order differ considerably among birds, but no study has experimentally investigated the function of variation in albumen or yolk egg content in the wild. In barn swallows (Hirundo rustica), absolute and relative albumen mass increased with egg laying order. Experimental albumen removal delayed hatching, had larger negative effects on growth of late-hatched nestlings, and reduced nestling survival. Laying order positively predicted hatch order. Because nestling competitive ability depends on size, and albumen egg content influences hatchling size, present results suggest that by increasing albumen content of late eggs mothers reduce hatching asynchrony and enhance growth particularly of late-hatched nestlings. Thus, variation in albumen mass with laying order may function to mitigate the negative phenotypic consequences of hatching late in species that adopt a ‘brood-survival’ strategy.
An indirect approach to imply trade-off shapes: population level patterns in resistance suggest a decreasingly costly resistance mechanism in a model insect system
Authors: Mealor M. A. , Boots M.
Published: October 2005

Trade-offs between life history and other traits play a key role in shaping the evolution of individuals. It is well established theoretically that the shapes of trade-off curves are as crucial to the evolutionary outcome as their strengths. However, measuring the shape of these relationships directly is often impractical. Here we use an indirect approach that examines the patterns seen within a population and then use theory to infer the shape of the trade-off curve. Using a bioassay we found that most individuals had either high susceptibility or relatively high resistance to a microparasite in a lepidopteran host population. According to general theory, this type of pattern in resistance would be most likely with a deceleratingly costly impact on fitness of increasing resistance. The implications and generality of the approach are discussed, along with the implications of the results to our understanding of the nature of innate resistance to parasites.
CD4+ T‐Cell Responses Against the VP1‐Unique Region in Individuals with Recent and Persistent Parvovirus B19 Infection
Authors: Lindner J. , Barabas S. , Saar K. , Altmann D. , Pfister A. , Fleck M. , Deml L. , Modrow S.
Published: October 2005

To date cellular immune responses against parvovirus B19 (B19) have not been studied extensively. The aim of this study was to examine the T‐cell response against the VP1‐unique region as the immunodominant part of the viral structural protein VP1 in individuals with different courses of B19 infection. Therefore, a group of 13 parvovirus‐positive probands was separated into subgroups characterized for recent or acute, past or persistent infection by means of the presence of specific immunoglobulin (Ig)M and IgG isotypes and of viral DNA in blood and tissue. Transiently transfected B‐cells expressing VP1‐unique region were used in ELISpot assays to investigate T‐cell responses directed against the VP1‐unique region in peripheral blood mononuclear cells (PBMC) of individual donors. Significant numbers of interferon‐γ (IFN‐γ) secreting lymphocytes were detectable in PBMC of all individuals with recent, acute or persistent B19 infection, but not in PBMC of donors with past B19 infection and seronegative individuals. A more detailed analysis of IFN‐γ producing cells by intracellular cytokine staining by flow cytometry revealed, that CD4+ T cells but not CD8+ cytotoxic lymphocytes (CTL) were the major subpopulation of IFN‐γ producing cells. These data strongly suggest the need of virus protein production for the maintenance of VP1‐unique region‐specific CD4+ T‐helper cell responses in B19‐infected individuals.