bluuebunny/crossref_metadata_2025 huggingface dataset:
Is Consequential Luck Morally Inconsequential? Empirical Psychology and the Reassessment of Moral Luck
Authors: Royzman Edward , Kumar Rahul
Published: August 2004

Philosophical discussions of the phenomenon that has come to be known as ‘moral luck’ have either dismissed it as illusory or touted it as the evidence for doubting the probative value of our commitment to certain widely avowed views concerning interpersonal assessments of responsibility. In this discussion, we present a third, distinctive interpretation of the moral luck phenomenon. Drawing upon empirically robust results from psychological studies of judgment bias, we argue that the phenomenon of moral luck is demonstrably not illusory. What we suggest, however, is that the phenomenon ought not to be taken to countenance doubts about the standards generally taken to be regulative of assessments of interpersonal responsibility. Rather, its significance lies in foregrounding certain generally unacknowledged obstacles we face in the process of conclusively applying general valid moral standards in making specific judgments of responsibility and desert.1
Honeydew amino acids in relation to sugars and their role in the establishment of ant‐attendance hierarchy in eight species of aphids feeding on tansy (Tanacetum vulgare)
Authors: Woodring J. , Wiedemann R. , Fischer M. K. , Hoffmann K. H. , Völkl W.
Published: August 2004

Abstract. The ratio of the concentration of honeydew total amino acids to total sugars in the honeydew of eight species of aphids, all feeding on tansy,Tanacetum vulgare(L.), was determined and correlated with honeydew production and ant‐attendance. The honeydew of the five ant‐attended aphid species [Metopeurum fuscoviride(Stroyan),Trama troglodytes(v. Hayd),Aphis vandergooti(Börner), Brachycardus cardui(L.),Aphis fabae(Scopoli)] was rich in total amino acids, ranging from 12.9 to 20.8 nmol µL−1compared with the unattended aphidMacrosiphoniella tanacetaria(Kalt.) with only 3 nmol µL−1. Asparagine, glutamine, glutamic acid and serine (all nonessential amino acids) were the predominant amino acids in the honeydew of all species. The total concentration of amino acids in the phloem sap of tansy was much higher (78.7 nmol µL−1) then in the honeydew samples, and the predominant amino acids were glutamate (34.3%) and threonine (17.7%). A somewhat unexpected result was the finding that those aphid species with the highest total amino acid concentration in the honeydew always had the highest concentration of sugars. The lowest amino acid–sugar combined value was 104–28.8 nmol µL−1in the non ant‐attended speciesM. tanacetaria, and the highest value was an average of 270–89.9 nmol µL−1for the three most intensely attended aphid speciesM. fuscoviride, A. vandergootiandT. troglodytes. There is no evidence that any single amino acid or group of amino acids in the honeydew acted as an attractant for ant‐attendance in these eight aphid species. The richness of the honeydew (rate of secretion × total concentration of sugars), along with the presence of the attractant sugar melezitose, comprised the critical factors determining the extent of ant‐attendance of the aphids feeding onT. vulgare. The high total amino acid concentration in sugar‐rich honeydews can be explained by the high flow‐through of nutrients in aphids that are particularly well attended by ants.
The haemagglutination activity in the different developmental stages and changes of this activity caused by analogues of insect hormones in two members of the Culex pipiens complex of mosquitoes
Authors: Gelbič I. , Olejníček J.
Published: August 2004

Abstract.  Haemagglutination activity was studied in last larval instars, pupae and adults of both sexes of the Culex pipiens mosquito complex. In females of Culex pipiens quinquefasciatus Say, an anautogenous member of C. pipiens complex, activity was detected in the homogenate of the head‐thorax complex, gut and remaining abdomen (after removing the gut), before and after sucking water, glucose solution or blood. Similar investigations were made in females of autogenous Culex pipiens molestus Forskal, a member of the same mosquito complex. The results were compared with data obtained for males of these subspecies, plus the larvae and pupae. The results show that haemagglutination activity in adult females depends not on the sucking of blood, but on the age of the females. In newly emerged females, the level of activity was very low, but after 24 h or 48 h of activity was highly enhanced, even in females that had no possibility to suck water or other liquids including blood. Furthermore, in C. p. molestus, the haemagglutination activity does not change in hungry or engorged females, and a high level of activity was found in the gut of last larval instars, a developmental stage that never takes blood. Treatment with methoprene reduces haemagglutination activity in both sexes, but 20‐hydroxycdysone application decreased activity in the gut of females. It is suggested that haemagglutination activity may be regulated indirectly by the endocrine system. The possibility that haemagglutination activity may depend on some aspect of the digestive system that has no direct connection to blood uptake is discussed. In addition, the activity may be important not only for the elimination of infections, but also for the processing of food and the utilization and transport of nutrients.
Teratocytes of the solitary endoparasitoid Meteorus gyrator (Hymenoptera: Braconidae): morphology, numbers and possible functions
Authors: Bell Howard A. , Kirkbride‐Smith Anne E. , Marris Gay C. , Edwards John P.
Published: August 2004

Abstract.  Laboratory studies investigated the development of teratocytes derived from the eggs of the parasitoid Meteous gyrator (Thun.) in its host, the tomato moth Lacanobia oleracea (L.). At hatching, each parasitoid egg produced an average of approximately 1000 teratocytes, but this number declined to approximately 400 during the course of parasitism. The teratocytes increased in size markedly, such that 7 days after egg hatch their mean diameter was approximately four times that of the cells immediately after dissociation. The haemolymph of parasitized hosts had reduced phenoloxidase activity, and teratocytes inhibited phenoloxidase activity when coincubated with plasma from nonparasitized hosts. The injection of teratocytes into nonparasitized fifth‐instar L. oleracea larvae suppressed growth and induced a supernumerary moult in some larvae. A number of parasitism‐specific proteins were detected in the haemolymph of parasitized hosts, and incubation of teratocytes in culture media indicated that these cells were a source of at least two of these proteins.
Vibratory signals of the harlequin bug and their transmission through plants
Authors: Čokl Andrej , Prešern Janez , Virant‐Doberlet Meta , Bagwell Glen J. , Millar Jocelyn G.
Published: August 2004

Abstract.  Males of the harlequin bug, Murgantia histrionica (Hahn), produce five different vibrational songs, whereas females produce one song. Songs differ from those of other stink bugs primarily in their species‐specific temporal characteristics. The broad band male courtship songs of M. histrionica are achieved by a combination of different frequency modulated and/or narrow band subunits, with several higher harmonic frequencies. Males rather than females initiate substrate‐borne vibrational communication, and the longer‐range calling songs found typically in other pentatomid species are lacking. Interindividual differences in song temporal and spectral characteristics are discussed. Transmission of vibrational songs through a cabbage head is more efficient along veins than along lamina. Attenuation of signals transmitted through veins is low and similar to that reported previously for plant stalks. On the leaf vein, distances between peak amplitude minima and maxima are different for the dominant and subdominant frequencies. At any distance from the vibration source, a different relationship between spectral peak amplitudes can be recorded. Resolution of these differences, together with velocity differences between signals recorded on the vein and lamina, may help small stink bugs to estimate distance and to locate each other on a plant.
Enzymatic capacity for accumulation of polyol cryoprotectants changes during diapause development in the adult red firebug, Pyrrhocoris apterus
Authors: Koštál Vladimír , Tamura Masahiro , Tollarová Michaela , Zahradníčková Helena
Published: August 2004

Abstract.  Diapausing adults of the red firebug, Pyrrhocoris apterus, were maintained in the laboratory at constant conditions of 20 °C and short days (LD 12 : 12 h) for 5 months. Spontaneous termination of diapause is seen in 0.4% of adults. At different times of diapause development, groups of adults were exposed to an 8‐week gradual cold treatment ending at 0 °C. Ribitol and sorbitol contents remain very low at constant 20 °C and their rapid accumulation only occurrs at temperatures below 5 °C. The capacity to accumulate ribitol in response to low temperature stimulus remains relatively stable but the capacity to accumulate sorbitol decreases to zero during the 5 months of diapause development. Glycogen (whole‐body and fat‐body reserves) accumulates relatively rapidly during the early phase (up to 1–2 months) and slowly depletes during the late phase of diapause development under constant conditions. Upon cold treatment, part of the glycogen reserve was depleted. The activities of most enzymes involved in polyol metabolism (namely glycogen phosphorylase, glucose‐6‐P dehydrogenase, phosphofructokinase, aldose reductase, polyol dehydrogenase and ketose reductase) increase relatively rapidly during the early phase of diapause development and, in the late phase, they either become stable or slowly decrease. Cold treatment has either no effect or results in a moderate increase in activity when applied in the early phase of diapause development but results in a more or less obvious decrease of enzymatic activity when applied in the late phase.
Influence of queen weight and colony origin on worker response in Solenopsis geminata
Authors: Rojas Julio C. , Brindis Yolanda , Malo Edi A. , Cruz‐López Leopoldo
Published: August 2004

Abstract. The influence of weight and colony origin of the queen of Solenopsis geminata (F.) (Hymenoptera: Formicidae) on worker attraction is studied under laboratory conditions. In the first experiment, worker response to individual queens of different weight from the same colony is evaluated. Heavier queens are more attractive than smaller queens to their own workers. In subsequent experiments, the colony origin effect is investigated and worker response to a pair of queens of the same weight from the same or different colonies is compared. When queens are from the same colony, workers do not show a significant preference between queens. However, when queens are from a different colony, workers are significantly more attracted to their own queen than to the foreign queen. Finally, the response of workers to queens of different weight from the same or different colonies is investigated. In both cases, workers are significantly more attracted to a heavier queen than a lighter queen, even if the lighter queen is their own queen. A putative pheromonal component (E)‐6‐(1‐pentenyl)‐2H‐2‐pyranone, is not positively correlated with queen weight.
Assessing the effects of low temperature on the establishment potential in Britain of the non‐native biological control agent Eretmocerus eremicus
Authors: Tullett A. G. , Hart A. J. , Worland M. R. , Bale J. S.
Published: August 2004

Abstract. Eretmocerus eremicus is a parasitoid wasp that is not native to Britain. It is a biological control agent of glasshouse whitefly and has recently been released under licence in Britain for the first time. This study assessed the effect of low temperature on the outdoor establishment potential of E. eremicus in Britain. The developmental threshold calculated by three linear methods was between 6.1° and 11.6 °C, with a degree‐day requirement per generation between 256.3 and 366.8° day−1. The supercooling points of non‐acclimated and acclimated larvae were similar (approximately −25 °C). Non‐acclimated and acclimated larvae were subject to considerable pre‐freeze mortality, with lethal temperature (LTemp50) values of −16.3 and −21.3 °C, respectively. Lethal time experiments indicated a similar lack of cold tolerance with 50% mortality of both non‐acclimated and acclimated larvae after 7 days at −5 °C, 10 days at 0 °C and 13 days at 5 °C. Field trials showed that neither non‐acclimated nor acclimated larvae survived longer than 1 month when exposed to naturally fluctuating winter temperatures. These results suggest that releasing E. eremicus into British greenhouses would pose minimal risk because typical British winter temperatures would be an effective barrier against establishment in the wild.
Dispersion of carbon dioxide plumes in African woodland: implications for host‐finding by tsetse flies
Authors: Zollner Gabriela E. , Torr Stephen J. , Ammann Christof , Meixner Franz X.
Published: August 2004

Abstract.  In Zimbabwe, high‐resolution (10 Hz to an accuracy of ± 0.1 p.p.m.) measurements were made of atmospheric and host‐produced CO2 in tsetse habitats during the dry season. The diel structure of atmospheric CO2 concentrations is bimodal, with a minimum at approximately 16.00 hours and maxima at approximately 05.00 hours and 20.00 hours, respectively. The background CO2 noise is greater in densely vegetated riverine woodland than in leafless, deciduous (mopane) woodland. Variation in atmospheric CO2 concentrations is correlated with decreasing wind speed and increasing thermal stability. Consequently, the background noise during the day is greatest in riverine woodland during early morning and late afternoon, when winds are typically light and stable, and thermal inversion conditions are developing. Measurements were made of CO2 at 8–64 m downwind from natural (two cattle) or synthetic sources (4–20 L min−1 CO2). The signal from the sources appears as fluctuations above threshold (approximately 355–362 p.p.m.), in the form of intermittent ‘bursts’ of CO2. The strength, duration and intermittency of the signals attributable to these sources declines with source strength and distance from the source. In riverine woodland, approximately 50% of all bursts are 0.1 s long, and 10% are > 2.0 s long. Carbon dioxide signals from equivalent sources are stronger in riverine woodland than mopane. Carbon dioxide dispensed at rates of 4–20 L min−1 is detected up to 64 m downwind of the source but peaks are typically < 10 p.p.m. above threshold. Consequently, host‐CO2 signals are obscured during periods of large fluctuations in atmospheric CO2. These results suggest that CO2 is detectable, at least in some circumstances, at tens of metres downwind and hence dispels the notion that its action is limited to that of a short‐range attractant.
Role of hydrocarbons in egg recognition in the honeybee
Authors: Martin Stephen J. , Jones Graeme R. , Châline Nicolas , Ratnieks Francis L. W.
Published: August 2004

Abstract.  Despite worker‐laid and queen‐laid honeybee eggs having significantly different hydrocarbon profiles, bioassays and chemical supplementation studies show that changing the hydrocarbon profile does not affect egg identity. Furthermore, full‐sized eggs that are tested just before being laid or just after being laid have similar hydrocarbon patterns but are treated differently in egg‐discrimination bioassays with only the laid eggs surviving. This suggests that hydrocarbons play no role in the egg‐recognition system in honeybees.
Directional characteristics of the auditory system of cicadas: is the sound producing tymbal an integral part of directional hearing?
Authors: Fonseca P. J. , Hennig R. M.
Published: August 2004

Abstract.  Directional hearing is investigated in males of two species of cicadas, Tympanistalna gastrica (Stål) and Tettigetta josei Boulard, that are similar in size but show different calling song spectra. The vibrational response of the ears is measured with laser vibrometry and compared with thresholds determined from auditory nerve recordings. The data are used to investigate to what extent the directional characteristic of the tympanal vibrations is encoded by the activity of auditory receptors. Laser measurements show complex vibrations of the tympanum, and reveal that directional differences are rather high (>15 dB) in characteristic but limited frequency ranges. At low frequencies, both species show a large directional difference at the same frequency (3–5 kHz) whereas, above 10 kHz, the directional differences correspond to the different resonant frequencies of the respective tymbals. Consequently, due to the mechanical resonance of the tymbal, the frequency range at which directional differences are high differs between the two species that otherwise show similar dimensions of the acoustic system. The directional differences observed in the tympanal vibrations are also observed in the auditory nerve activity. These recordings confirm that the biophysically determined directional differences are available within the nervous system for further processing. Despite considerable intra as well as interindividual variability, the ears of the cicadas investigated here exhibit profound directional characteristics, because the thresholds determined from recordings of the auditory nerve at 30° to the right and left of the longitudinal axis differ by more than 5 dB.
Consumption Externalities, Habit Formation and Equilibrium Efficiency*
Authors: Alonso‐Carrera Jaime , Caballé Jordi , Raurich Xavier
Published: August 2004

We analyze the welfare properties of the competitive equilibrium in a capital accumulation model where individual preferences are subject to both habit formation and consumption spillovers. Using an additive specification for preferences, according to which the argument in the utility function is a linear combination of present and past values of own consumption and consumption spillovers, we analyze the circumstances under which these spillovers are a source of inefficiency. It is shown that consumption externalities have to interact with habits in order to generate an inefficient dynamic equilibrium. Finally, we characterize optimal tax policies aimed at restoring efficient decentralized paths.
What Determines Real Exchange Rates? The Nordic Countries
Authors: Bergvall Anders
Published: August 2004

The model derived in this paper yields testable implications concerning the long‐run co‐movements of real exchange rates, relative labor productivity, the trade balance and terms of trade. Countries with relatively higher output growth, trade deficits or improved terms of trade are found to have more appreciated real exchange rates, with the main channel of transmission working through the relative price of nontraded goods. Exogenous terms‐of‐trade shocks are found to be the most important determinant of long‐run movements in the real exchange rate for Denmark and Norway, while demand shocks account for most of the long‐run variance in the real exchange rate for Finland and Sweden.
Is the MPC's Voting Record Informative about Future UK Monetary Policy?
Authors: Gerlach‐Kristen Petra
Published: August 2004

It is shown that the voting record of the Monetary Policy Committee of the Bank of England helps predict future policy rate changes. This result is robust to the inclusion of market participants’ expectations as measured by the slope of the term structure of money market rates and interest rate futures. Moreover, expectations seem to adjust to the information contained in the voting record, which suggests that publishing the minutes of MPC meetings increases the transparency of monetary policy.
A General Approach to Welfare Measurement through National Income Accounting*
Authors: Asheim Geir B. , Buchholz Wolfgang
Published: August 2004

A framework is developed for analyzing national income accounting using a revealed welfare approach that is sufficiently general to cover, both the standard discounted utilitarian and maximin criteria as special cases. We show that the basic welfare properties of comprehensive national income accounting, previously ascribed only to the discounted utilitarian case, extend to this more general framework. In particular, under a wider range of circumstances, it holds that real NNP growth (or, equivalently, a positive value of net investments) indicates welfare improvement. We illustrate the applicability of our approach in the Dasgupta–Heal–Solow model of capital accumulation and resource depletion.
Tax Base and Crowding‐in Effects of Balanced Budget Fiscal Policy
Authors: Linnemann Ludger
Published: August 2004

A dynamic general equilibrium business cycle model is constructed with staggered price adjustment, monopolistic wage setting and distortionary taxation. The government purchases goods, runs an unemployment benefit system and balances its budget through a proportional tax on labour income. A temporary tax‐financed increase in government expenditures can lower the tax rate through a demand‐induced widening of the tax base. It is shown analytically that this allows private consumption to rise, under realistic conditions, despite the negative wealth effect of increased fiscal spending.
Public Employment and Regional Risk Sharing*
Authors: Borge Lars‐Erik , Matsen Egil
Published: August 2004

We provide an empirical analysis of regional risk sharing in Norway over the period 1977–90. The approach of Asdrubali, Sørensen and Yosha (1996) is extended to take public employment into account as a possible shock absorber. The other channels of risk sharing are capital markets and commuting, taxes and transfers, and credit markets. The estimated degree of regional consumption insurance is very high. We cannot reject the hypothesis that there is full interregional risk sharing in the short term. Public employment absorbs up to 25 percent of private sector output shocks in our analyses. Generally, central government insurance against regional shocks is relatively more important, the more permanent the shocks are, and vice versa for market‐based risk‐sharing channels.
How Flexibility Facilitates Innovation and Ways to Manage it in Organizations
Authors: Georgsdottir Asta S. , Getz Isaac
Published: August 2004

Flexibility is the capacity to change and to adapt to a challenging environment. It can be either adaptive – when challenges are present in the environment – or spontaneous – a preference for change without any external pressure. Change and adaptation are also key elements of innovation. In this article, we examine how different types of flexibility can play a major part in the innovation process. First, we discuss how flexible cognition and a flexible personality can facilitate the generation of innovations. Second, we discuss how flexibility can be beneficial to the audience for innovations. Lastly, we use the previous discussion of the benefits of flexibility for innovation to illuminate and present some approaches to the improvement of flexibility – both of employees and of the audience – for innovation. These approaches come both from other researchers’ work and from our own original research on the best practices of innovation management in Europe.
Evocation Processes by Novice and Expert Designers: Towards Stimulating Analogical Thinking
Authors: Bonnardel Nathalie , Marmèche Evelyne
Published: August 2004

Design activity occurs in many professions, ranging from technical to more artistic domains. Whatever the domain, it is a constant challenge for designers to introduce creativity in each design project they work on and minimize the tendency to repeat familiar design features. The goal of this paper is to present a cognitive approach to design problem solving as well as an experimental study. This study aims at determining whether creative ideas can be enhanced by the presentation of external sources of inspiration. In particular, we analyse the effect of the presentation of different kinds of sources (intra‐versusinterdomain sources, which are presented as graphical representations or as verbal labels) according to the designers’ level of expertise (lay‐designersversusprofessionals). Results show that it is possible to enhance evocation processes in design, but that it is dependent on both the nature of sources of inspiration and the designers’ level of expertise. Based on these results, we suggest ways for enhancing creative ideas in design tasks.
Book Review
Authors: Butler Jeff
Published: August 2004

Henry Chesbrough (2003), Open Innovation – The New Imperative for Creating and Profiting from Technology. HBS Press, Boston. ISBN 1‐57851‐837‐7, 227 pp, US$35‐00
A numerical comparison of 2D resistivity imaging with 10 electrode arrays
Authors: Dahlin Torleif , Zhou Bing
Published: August 2004

Numerical simulations are used to compare the resolution and efficiency of 2D resistivity imaging surveys for 10 electrode arrays. The arrays analysed include pole‐pole (PP), pole‐dipole (PD), half‐Wenner (HW), Wenner‐α (WN), Schlumberger (SC), dipole‐dipole (DD), Wenner‐β (WB), γ‐array (GM), multiple or moving gradient array (GD) and midpoint‐potential‐referred measurement (MPR) arrays. Five synthetic geological models, simulating a buried channel, a narrow conductive dike, a narrow resistive dike, dipping blocks and covered waste ponds, were used to examine the surveying efficiency (anomaly effects, signal‐to‐noise ratios) and the imaging capabilities of these arrays. The responses to variations in the data density and noise sensitivities of these electrode configurations were also investigated using robust (L1‐norm) inversion and smoothness‐constrained least‐squares (L2‐norm) inversion for the five synthetic models.

The results show the following. (i) GM and WN are less contaminated by noise than the other electrode arrays. (ii) The relative anomaly effects for the different arrays vary with the geological models. However, the relatively high anomaly effects of PP, GM and WB surveys do not always give a high‐resolution image. PD, DD and GD can yield better resolution images than GM, PP, WN and WB, although they are more susceptible to noise contamination. SC is also a strong candidate but is expected to give more edge effects. (iii) The imaging quality of these arrays is relatively robust with respect to reductions in the data density of a multi‐electrode layout within the tested ranges. (iv) The robust inversion generally gives better imaging results than the L2‐norm inversion, especially with noisy data, except for the dipping block structure presented here. (v) GD and MPR are well suited to multichannel surveying and GD may produce images that are comparable to those obtained with DD and PD. Accordingly, the GD, PD, DD and SC arrays are strongly recommended for 2D resistivity imaging, where the final choice will be determined by the expected geology, the purpose of the survey and logistical considerations.
The effect of the electrical anisotropy on the response of helicopter‐borne frequency‐domain electromagnetic systems
Authors: Yin Changchun , Fraser Douglas C.
Published: August 2004

Helicopter electromagnetic (HEM) systems are commonly used for conductivity mapping and the data are often interpreted using an isotropic horizontally layered earth model. However, in regions with distinct dipping stratification, it is useful to extend the model to a layered earth with general anisotropy by assigning each layer a symmetrical 3 × 3 resistivity tensor.

The electromagnetic (EM) field is represented by two scalar potentials, which describe the poloidal and toroidal parts of the magnetic field. Via a 2D Fourier transform, we obtain two coupled ordinary differential equations in the vertical coordinate. To stabilize the numerical calculation, the wavenumber domain is divided into two parts associated with small and large wavenumbers. The EM field for small wavenumbers is continued from layer to layer with the continuity conditions. For large wavenumbers, the EM field behaves like a DC field and therefore cannot be sensed by airborne EM systems. Thus, the contribution from the large wavenumbers is simply ignored.

The magnetic fields are calculated for the vertical coaxial (VCX), horizontal coplanar (HCP) and vertical coplanar (VCP) coil configurations for a helicopter EM system. The apparent resistivities defined from the VCX, VCP and HCP coil responses, when plotted in polar coordinates, clearly identify the principal anisotropic axes of an anisotropic earth. The field example from the Edwards Aquifer recharge area in Texas confirms that the polar plots of the apparent resistivities identify the principal anisotropic axes that coincide well with the direction of the underground structures.
Comparison of methods for modelling the behaviour of bubbles produced by marine seismic airguns
Authors: Cox E. , Pearson A. , Blake J.R. , Otto S.R.
Published: August 2004

Three models for the dynamics of seismic airgun‐generated bubbles and their associated far‐field signals are developed and compared with geophysical data. The first model of an airgun‐generated bubble uses a spherical approximation, the second is an approximate Lagrangian model which allows for small deformations from a spherical shape, whilst the final model is an axisymmetric boundary‐integral method which permits the bubble to evolve into highly non‐spherical geometries. The boundary‐integral method also allows both geometric interference and strong dynamic interactions in multi‐bubble studies.

When comparing the spherical model to experimental data there are three apparent, significant differences: the magnitude of the primary pressure peak, which is greater in the model; the subsequent decay of the pressure peaks and motion – the experimental data demonstrating greater decay and a slower rise rate; and the frequency of oscillation, which is slower in the experimental data. It is believed that the first discrepancy is due to the initial stages of expansion where the compressed air is forced to sparge through the airgun ports. The other differences indicate that there is some other energy‐loss mechanism which is not accounted for in the spherical bubble model. Non‐spherical bubble behaviour is investigated through the use of two different deformable many‐bubble codes and their predictions are compared with the spherical model and experimental data.

The Lagrangian model predicts the formation of a buoyancy‐driven liquid jet on the first collapse of a typical airgun bubble; however, the model breaks down when the bubble becomes significantly deformed, due to a low‐order spherical‐harmonic approximation for the potential. The axisymmetric boundary‐integral code models the jet shape accurately and it is found that these bubbles evolve to toroidal geometries when the jet impacts on the opposite surface of the bubble. This highly non‐spherical behaviour is readily observed on high‐speed films of airgun bubbles, and is one key source of energy loss; it damps the pulsations of the bubble and slows its rise speed.

Inter‐bubble interactions are investigated using the two deformable bubble models, and the predictions are compared to field data. It was found that as the bubbles approach each other, their periods of oscillation increase in accordance with observations, and jets are formed in the direction of motion upon collapse.
The influence of induced polarization on long‐offset transient electromagnetic data
Authors: Hoheisel Andreas , Hördt Andreas , Hanstein Tilman
Published: August 2004

The diffusion of electromagnetic fields is dependent not only on conductivity, but also on magnetic permeability, dielectric permittivity and polarizability, i.e. dispersive conductivity. The long‐offset transient electromagnetic (LOTEM) method is mainly used to determine the spatial distribution of conductivity in the subsurface. However, earlier work on loop‐loop TEM suggests that transient EM methods can also be affected by induced polarization (IP).

Numerous 1D forward calculations were carried out to study the IP effect on LOTEM data, using the Cole‐Cole relaxation model to simulate the polarizability of the ground. Besides the polarizability of each layer, the IP effect depends on the LOTEM field set‐up and the spatial distribution of conductivity in the ground. In particular, near‐surface layers with high chargeabilities can significantly distort the late time transients of the electric field components in the vicinity of the transmitter. The influence of polarizable layers on the magnetic field components can be neglected under normal circumstances.

In 1997 and 1999, LOTEM measurements were carried out at Mt. Vesuvius in Italy to explore the geological structure of the volcano. Sensitivity studies on the effect of polarizable layers suggest that high chargeabilities in connection with conductive layers at greater depths would result in a detectable distortion of the electric field transients. Although the simultaneous IP measurements revealed high chargeabilities in a near‐surface layer, no evidence of IP effects could be found in the measured LOTEM data. We conclude that the observed chargeabilities are local and that 3D effects are probably present in the data.

Another aspect is the measurement of the system response, which is usually measured by placing a receiver very close to the transmitter. Therefore, large distortions can be expected if near‐surface polarizable layers exist. This was verified in practice by field measurements in an area with high chargeabilities in Longerich, Cologne.
Velocity model estimation for depth imaging: Comparison of three tomography methods on a 2D real data set
Authors: Bégat Soazig Le , Chauris Hervé , Devaux Vincent , Nguyen Sylvain , Noble Mark
Published: August 2004

The estimation of velocity models is still crucial in seismic reflection imaging as it controls the quality of the depth‐migrated image, which is the basis of geological interpretation. Among the numerous existing methods for velocity determination, tomographic methods are very attractive for their efficiency and ability to retrieve heterogeneities of the medium. We present three tomographic methods in order to estimate heterogeneous velocity models from 2D prestack PP reflection data: a traveltime tomography in the time‐migrated domain, a traveltime and slope tomography in the non‐migrated time domain, and a slope tomography in the depth‐migrated domain.

The first method (traveltime tomography in the time domain) is based on continuous picked events, whereas the two slope tomographic methods, one in the time domain and the other in the depth domain, are based on locally coherent events, with no assumptions about reflector geometry or the unknown velocity field. The purpose of this paper is not to describe in detail the theoretical basis and implementation of the methods, but to apply and compare their output using the same marine real data set. Based on the estimated velocity models, the migrated images and the common‐image gathers from the three processing routes, the relative strengths and weaknesses of the methods are discussed. Finally, similarities are indicated and potential alternative approaches are proposed.
Airborne EM skin depths
Authors: Beamish David
Published: August 2004

Skin depth is an electromagnetic (EM) scale length that provides a measure of the degree of attenuation experienced by a particular frequency of an EM system. As has been discussed in the literature, skin depth is not a complete measure of the depth of investigation, but the two may be related. Frequency‐domain airborne EM systems employ pairs of transmitter and receiver coils that use a frequency range from several hundred hertz to over 100 kHz. For elevated dipoles, both geometrical and frequency‐dependent attenuation of the induced fields must be considered. For airborne EM systems it is possible to define a skin depth based only on the electric field induced by the transmitter. A vertical decay scale length, here defined from the at‐surface position of maximum electric field, enables the same skin‐depth estimate to be obtained for both cases of vertical and horizontal dipolar excitation. Such dipolar skin depths associated with towed‐bird and fixed‐wing airborne systems are studied in relation to frequency, conductivity and sensor elevation. Dipolar skin depths are found to be much smaller than their plane‐wave counterparts except at high frequency (>50 kHz) and in combination with high conductivity. For the majority of airborne systems the influence of altitude on skin depth is highly significant. Dipolar skin depths increase with increasing sensor elevation. Low frequencies display the greatest sensitivity. At low elevation (<40 m), geometrical attenuation dominates the behaviour of the skin depth. The study indicates that typical low‐altitude airborne surveys provide vertically compact assessments of subsurface conductivity, well suited to near‐surface, environmental applications.
The use of vapor phase extraction in metabolic profiling of phytohormones and other metabolites
Authors: Schmelz Eric A. , Engelberth Juergen , Tumlinson James H. , Block Anna , Alborn Hans T.
Published: August 2004

Through complex networks of signaling interactions, phytohormones regulate growth, development, reproduction and responses to biotic and abiotic stress. Comprehensive metabolomic approaches, seeking to quantify changes in vast numbers of plant metabolites, may ultimately clarify these complex signaling interactions and consequently explain pleiotropic effects on plant metabolism. Synergistic and antagonistic phytohormone signaling interactions, referred to as crosstalk, are often considered at the level of transduction without proper consideration of synthesis or accumulation of phytohormones because of the limitation and difficulty in quantifying numerous signals. Significant progress has recently been made in the expansion of metabolic profiling and analysis of multiple phytohormones [Birkemeyer et al. (J. Chromatogr. A, 2003, 993, 89); Chiwocha et al. (Plant J., 2003, 35, 405); Müller et al. (Planta, 2002, 216, 44); Schmelz et al. (Proc. Natl Acad. Sci. USA, 2003, 100, 10552)]. We recently presented a novel metabolic profiling approach to the analysis of acidic phytohormones and other metabolites based on a simplistic preparation scheme and analysis by chemical ionization‐gas chromatography/mass spectrometry. We now provide a detailed description of this vapor phase extraction technique and use pathogen infection of Arabidopsis with Pseudomonas syringae DC3000 to illustrate metabolic changes in salicylic acid, cinnamic acid, jasmonic acid, indole‐3‐acetic acid, abscisic acid, unsaturated C18 fatty acids, 12‐oxo‐phytodienoic acid, and phytotoxin coronatine. Directions for further method expansion are provided and include issues of recovery, derivatization, range of accessible analytes, optimization, reproducibility and future directions.
ESTs, cDNA microarrays, and gene expression profiling: tools for dissecting plant physiology and development
Authors: Alba Rob , Fei Zhangjun , Payton Paxton , Liu Yang , Moore Shanna L. , Debbie Paul , Cohn Jonathan , D'Ascenzo Mark , Gordon Jeffrey S. , Rose Jocelyn K. C. , Martin Gregory , Tanksley Steven D. , Bouzayen Mondher , Jahn Molly M. , Giovannoni Jim
Published: August 2004

Gene expression profiling holds tremendous promise for dissecting the regulatory mechanisms and transcriptional networks that underlie biological processes. Here we provide details of approaches used by others and ourselves for gene expression profiling in plants with emphasis on cDNA microarrays and discussion of both experimental design and downstream analysis. We focus on methods and techniques emphasizing fabrication of cDNA microarrays, fluorescent labeling, cDNA hybridization, experimental design, and data processing. We include specific examples that demonstrate how this technology can be used to further our understanding of plant physiology and development (specifically fruit development and ripening) and for comparative genomics by comparing transcriptome activity in tomato and pepper fruit.
Human atopic dermatitis: a disease at the frontier between allergy and autoimmunity
Authors: Bieber T.
Published: August 2004

Atopic dermatitis (AD) is a chronic inflammatory skin disease that develops on a complex genetic background, the so‐called atopic diathesis. Genetic epidemiological studies based on linkage analysis with full genome scan strategies, as well as association and case‐controlled studies, have unravelled several chromosomal loci with putative candidate genes. These loci were revealed to be distinct from those newly identified for allergic asthma. Some of these genes localized on chromosomes 3, 17 and 20 are shared with psoriasis, another chronic inflammatory skin disease. These observations suggest, at least, the role of putative genes involved in the down‐regulation of inflammation in the skin. Single nucleotide polymorphisms have been identified in several genes for which the functional significance remains to be determined. In most (70–80%), but not all patients, AD is characterized by the presence of elevated total serum IgE levels. However, a subgroup of atopic patients (20–30%) exhibit normal IgE levels. Mechanisms contributing to the extrinsic/IgE‐mediated and the intrinsic/non‐IgE‐mediated forms have been the focus of intensive research in recent years. These forms have been particularly studied in the context of AD, which has lead to new nomenclature recently approved by the World Allergy Organization. Moreover, we now have increasing evidence for the putative role of an autoimmune phenomenon in the complex pathophysiology of atopic dermatitis. Mainly adult patients exhibit specific IgE directed against self‐proteins of epidermal origin. A new picture emerges in which the natural history of AD seems to be divided into three phases. First, an initial intrinsic phase, eczema, occurs in early infancy. This is then followed in 60–80% of cases by a sensitization to food and/or environmental allergens with the development of the extrinsic phase, true AD. In this form, it is speculated that antigen‐presenting cells expressing the high‐affinity receptor for IgE (FcεRI) play a major role in the control of inflammation. Consequently, these AD patients will have benefit from prevention measures. Finally, most probably due to molecular mimicry, an IgE sensitization to self‐proteins is observed in 60–80% of AD patients. Whether these specific IgE antibodies have a pathophysiological role or are only to be considered as an epiphenomenon remains to be clarified. In summary, due to rapid advancements in the research field of atopic diseases, it now becomes possible for the first time to delineate a new disease classification of allergic and nonallergic subtypes of atopic diseases, thereby bringing hope to the clinician for a more specific treatment approach for each subgroup of these patients.
Effect of recombinant canine IFNγ on canine atopic dermatitis evaluated by clinical signs, histopathology and expression of Th1/Th2 cytokine mRNA
Authors: Iwasaki T. , Kagawa Y. , Park S. J. , Kanazawa N. , Momoi Y. , Tanikawa H.
Published: August 2004

Atopic dermatitis (AD) is thought to be caused by immunologic abnormalities expressed as a Th1/Th2 cytokine imbalance in both humans and dogs. Several studies have focused on the therapeutic effects of IFNγ in human AD with successful results; however, the mechanism of action of IFNγ is not fully understood. We investigated the effect of recombinant canine interferon gamma (rCaIFNγ) on 10 dogs with AD and evaluated the ratio of IL‐4 mRNA to IFNγ mRNA in peripheral blood mononuclear cells, serum total IgE levels, and histological changes in skin. After six injections of rCaIFNγ over a span of 2 weeks, seven of the 10 dogs showed improvement, and six of these seven dogs exhibited decreased IL‐4:IFNγ mRNA ratios. Two of the three cases that did not improve had increased IL‐4:IFNγ mRNA ratios. Total serum IgE levels were significantly decreased in nine of 10 cases. The number of IgE‐positive cells detected by immunostaining and the number of mast cells in skin biopsy samples were decreased. A reduction of epidermal cell layers was demonstrated by histopathology after treatment. These results demonstrated that rCaIFNγ may be a novel safe and effective therapeutic option for the treatment of canine AD, and the mechanism of action of rCaIFNγ may be related to the modulation of Th2 cytokines to Th1 cytokines with the reduction of serum IgE production.

Funding: Self‐funded.
Effects of the immunomodulatory drugs tacrolimus, rapamycin and cilomilast on dendritic cell function in a model of allergic contact dermatitis
Authors: Bäumer W. , Sülzle B. , Weigt H. , Hecht M. , Kietzmann M.
Published: August 2004

The in vitro and in vivo immunomodulatory effects of the phosphodiesterase 4 inhibitor cilomilast were compared to tacrolimus and rapamycin, immunosuppressive drugs used in organ transplantation. Tacrolimus is also registered for treatment of human atopic dermatitis. In vitro, the effect of the substances on the mixed leucocyte reaction (dendritic cell‐mediated T‐cell activation) was tested. Cilomilast and tacrolimus, as well as rapamycin, were able to inhibit proliferation in a dose‐dependent manner. In vivo, the substances were tested in a model of allergic contact dermatitis. Toluene‐2,4‐diisocyanate (TDI)‐induced allergic contact dermatitis in BALB/c mice is characterized by a Th2‐mediated allergic inflammatory reaction, demonstrated by an increase of IL‐4 and an unchanged level of IL‐12 in inflamed tissues. It was our aim to compare the inhibitory effect of the drugs on the TDI‐induced allergic inflammatory response (ear swelling). After oral and intraperitoneal administration, only tacrolimus induced a distinct inhibition of the TDI‐mediated ear swelling 16 h after challenge. Cilomilast as well as rapamycin failed to do so. After topical administration, cilomilast and tacrolimus, but not rapamycin, inhibited the inflammatory response. Therefore, we compared the combination of topical and systemic administration of cilomilast and tacrolimus in the main experiment. Cilomilast (20 mg/kg) was administered intraperitoneally 16 and 0.5 h before challenge and topically onto mouse ears (3% in 20 μL acetone/DMSO 9:1) 2 h before challenge. Tacrolimus was given via the same routes (systemically 2.5 mg/kg and topically 0.5%) at the same time points as cilomilast. Both substances induced a significant inhibition of the ear swelling measured 16 h after TDI challenge. The mice were sacrificed, draining auricular lymph nodes were weighed, and lymph node cells were counted. Compared to vehicle‐treated mice, both lymph node weight and cell count were significantly reduced in tacrolimus‐treated mice and slightly reduced in cilomilast‐treated mice. Additionally, the dorsal half of the treated ears was cultivated for a skin dendritic cell migration assay. In contrast to a former study in which cilomilast strongly inhibited dendritic cell migration in nonsensitized skin, there was no inhibition of dendritic cell migration by cilomilast or tacrolimus in TDI‐challenged skin. In conclusion, the mixed leucocyte reaction in combination with an in vivo contact dermatitis model is a superior system to predict the efficacy of compounds for the treatment of allergic skin diseases compared to either method alone. Cilomilast and tacrolimus exert anti‐inflammatory effects in this model of allergic contact dermatitis and the mixed leucocyte reaction, but dendritic cell migration through the skin seems to be unaffected.

Funding: Self‐funded.