bluuebunny/crossref_metadata_2025 huggingface dataset:
ARTISTIC LABOR MARKETS AND CAREERS
Authors: Menger Pierre-Michel
Published: July 2002

▪ Abstract  Artistic labor markets are puzzling ones. Employment as well as unemployment are increasing simultaneously. Uncertainty acts not only as a substantive condition of innovation and self-achievement, but also as a lure. Learning by doing plays such a decisive role that in many artworlds initial training is an imperfect filtering device. The attractiveness of artistic occupations is high but has to be balanced against the risk of failure and of an unsuccessful professionalization that turns ideally non-routine jobs into ordinary or ephemeral undertakings. Earnings distributions are extremely skewed. Risk has to be managed, mainly through flexibility and cost reducing means at the organizational level and through multiple job holding at the individual level. Job rationing and an excess supply of artists seem to be structural traits associated with the emergence and the expansion of a free market organization of the arts.

Reviewing research done not only by sociologists, but also by economists, historians and geographers, our chapter focuses on four main issues: the status of employment and career patterns, the rationales of occupational choice, occupational risk diversification, and the oversupply of artists.
ORGANIZATIONAL INNOVATION AND ORGANIZATIONAL CHANGE
Authors: Hage J. T.
Published: July 2002

▪ Abstract  Three ideas—a complex division of labor, an organic structure, and a high-risk strategy—provoke consistent findings relative to organizational innovation. Of these three ideas, the complexity of the division of labor is most important because it taps the organizational learning, problem-solving, and creativity capacities of the organization. The importance of a complex division of labor has been underappreciated because of the various ways in which it has been measured, which in turn reflect the macroinstitutional arrangements of the educational system within a society. These ideas can be extended to the study of interorganizational relationships and the theories of organizational change. Integrating these theories would provide a general organizational theory of evolution within the context of knowledge societies.
The Great Agricultural Transition: Crisis, Change, and Social Consequences of Twentieth Century US Farming
Authors: Lobao Linda , Meyer Katherine
Published: July 2002

▪ Abstract  One of the most profound changes in the United States in the past century is the national abandonment of farming as a livelihood strategy. This change is evident both in the exodus of Americans from farming and in the conditions faced by the farmers remaining, most of whom are marginal producers in an increasingly concentrated industry. In this article, we provide a retrospective account of the empirical and sociological fate of family farmers. While sociologists have had longstanding interest in agrarian change, research on contemporary farmers is largely confined to speciality publications, with a loss to the discipline at large. We examine three distinct research traditions that continue to document farm transformation: research on macro-level transformation, community impacts, and household response. While these traditions evolved separately, we describe how they overlap and inform each other. Most notably, research on household and community responses delineates meso- and micro-level institutional factors that extend macro-level theory. Research on the contemporary farm population offers an alternative context in which to interrogate conventional accounts of economic development; such research yields insights about aspects of social life being rediscovered as part of the new economy and continues to pull sociologists into politically charged public policy debates.
KDR (VEGF Receptor 2) Is the Major Mediator for the Hypotensive Effect of VEGF
Authors: Li Bing , Ogasawara Annie K. , Yang Renhui , Wei Wei , He Guo-Wei , Zioncheck Thomas F. , Bunting Stuart , de Vos Abraham M. , Jin Hongkui
Published: July 2002

Vascular endothelial growth factor (VEGF) exerts vasodilation-induced hypotension as a major side effect for treatment of ischemic diseases. VEGF has 2 receptor tyrosine kinases, KDR and Flt-1. Little is known about which receptor mediates VEGF-induced hypotension. To elucidate the role of each receptor in mediating hypotension, KDR-selective and Flt-1–selective mutants were used for in vitro and in vivo studies. The KDR-selective mutant induced vascular endothelial cell proliferation comparable to VEGF, whereas the Flt-1– selective mutant had no effect on proliferation. Intravenous injection of KDR-selective mutant, Flt-selective mutant, or VEGF caused a dose-related decrease in mean arterial pressure in conscious rats. The hypotensive response to KDR-selective mutant was significantly less than that to VEGF (
P
<0.01) but was greater than that to Flt-selective mutant (
P
<0.01). Similarly, VEGF and KDR-selective mutant induced more potent vasorelaxation than Flt-selective mutant or placenta growth factor that binds Flt-1 only (
P
<0.01), and the vasorelaxation to KDR-selective mutant was not significantly different at low concentrations but less than that to VEGF at high concentrations. The results indicate that the vasodilation and hypotensive effect of VEGF may involve both receptors, but KDR is the predominant receptor mediating this effect. Because KDR-selective mutant induced proliferation and angiogenesis similar to VEGF but was associated with 36% attenuation in hypotension, the data suggest that the KDR-selective mutant may represent an alternative treatment for ischemic diseases.
Clashes in the Assembly
Authors: Voeten Erik
Published: July 2002

I apply nominate scaling to analyze a database of Cold War and post–Cold War roll call votes in the United Nations General Assembly. I investigate the dimensionality and stability of global conflict as well as the substantive content of the voting alignments that have replaced the Cold War East-West dimension. I find that post–Cold War conflict in the UN General Assembly is mostly one-dimensional. This single dimension positions countries on a continuum that runs from a group of Western countries at one extreme to a “counterhegemonic” bloc of countries that frequently clashes with the West, and the United States in particular. Levels of democracy and wealth are important independent determinants of the voting behavior of states. The positions of countries along the single dimension are remarkably stable across time, issue area, and issue importance. Except for the Eastern European countries switching sides, they are very similar to the positions on the Cold War East-West dimension. Contrary to expectations, post–Cold War conflict shows little resemblance to Cold War North-South conflict.
Stabilizing the Peace After Civil War: An Investigation of Some Key Variables
Authors: Hartzell Caroline , Hoddie Matthew , Rothchild Donald
Published: July 2002

In the wake of negotiated settlements to civil wars, one critical problem involves reassuring people who have been killing one another that conflict is not about to break out again, endangering people's lives. Those concerned with the success of negotiated settlements have debated how best to enhance the prospects of a stable peace. We address this question by exploring variables that may explain the longevity of negotiated peace settlements. These variables are divided into two categories—one tapping into the potential effects of the environment in which settlements are negotiated and another focusing on the impact of settlement arrangements. On the basis of our analysis of thirty-eight civil war settlements negotiated between 1945 and 1998 we identify the environmental factors and institutional choices that affect the short-term stability of the peace following civil war.
Interindividual Variation in Human Visual Performance
Authors: Halpern Scott D. , Andrews Timothy J. , Purves Dale
Published: July 2002

The responses of 20 young adult emmetropes with normal color vision were measured on a battery of visual performance tasks. Using previously documented tests of known reliability, we evaluated orientation discrimination, contrast sensitivity, wavelength sensitivity, vernier acuity, direction-of-motion detection, velocity discrimination, and complex form identification. Performance varied markedly between individuals, both on a given test and when the scores from all tests were combined to give an overall indication of visual performance. Moreover, individual performances on tests of contrast sensitivity, orientation discrimination, wavelength discrimination, and vernier acuity covaried, such that proficiency on one test predicted proficiency on the others. These results indicate a wide range of visual abilities among normal subjects and provide the basis for an overall index of visual proficiency that can be used to determine whether the surprisingly large and coordinated size differences of the components of the human visual system (Andrews, Halpern, & Purves, 1997) are reflected in corresponding variations in visual performance.
Set-and Code-Specific Activation in the Frontal Cortex: An fMRI Study of Encoding and Retrieval of Faces and Words
Authors: McDermott Kathleen B. , Buckner Randy L. , Petersen Steven E. , Kelley William M. , Sanders Amy L.
Published: July 2002

The frontal cortex has been described as playing both “setspecific” and “code-specific” roles in human memory processing. Set specificity refers to the finding of goal-oriented differences in activation patterns (e.g., encoding relative to retrieval). Code specificity refers to the finding of different patterns of activation for different types of stimuli (e.g., verbal/nonverbal). Using a two (code: verbal, nonverbal) by two (set: encoding, retrieval) within-subjects design and fMRI, we explored the influence of type of code and mental set in two regions in the frontal cortex that have been previously shown to be involved in memory. A region in the dorsal extent of the inferior frontal gyrus (BA 6/44) demonstrated code-specific effects. Specifically, an interaction of material type with hemisphere was obtained, such that words produced predominantly left-lateralized activation, whereas unfamiliar faces elicited predominantly right-lateralized activation. A region of the right frontal polar cortex (in or near BA 10), which has been activated in many memory retrieval studies, showed set-specific activation in that it was more active during retrieval than encoding. These data demonstrate that distinct regions in the frontal cortex contribute in systematic yet different ways to human memory processing.
Stable and Rapid Recurrent Processing in Realistic Autoassociative Memories
Authors: Battaglia Francesco P. , Treves Alessandro
Published: July 2002

It is shown that in those autoassociative memories that learn by storing multiple patterns of activity on their recurrent collateral connections, there is a fundamental conflict between dynamical stability and storage capacity. It is then found that the network can nevertheless retrieve many different memory patterns, as predicted by nondynamical analyses, if its firing is regulated by inhibition that is sufficiently multiplicative in nature. Simulations of a model network with integrate-and-fire units confirm that this is a realistic solution to the conflict. The simulations also confirm the earlier analytical result that cued-elicited memory retrieval, which follows an exponential time course, occurs in a time linearly related to the time constant for synaptic conductance inactivation and relatively independent of neuronal time constants and firing levels.
Detecting and Estimating Signals in Noisy Cable Structures, I: Neuronal Noise Sources
Authors: Manwani Amit , Koch Christof
Published: July 2002

In recent theoretical approaches addressing the problem of neural coding, tools from statistical estimation and information theory have been applied to quantify the ability of neurons to transmit information through their spike outputs. These techniques, though fairly general, ignore the specific nature of neuronal processing in terms of its known biophysical properties. However, a systematic study of processing at various stages in a biophysically faithful model of a single neuron can identify the role of each stage in information transfer. Toward this end, we carry out a theoretical analysis of the information loss of a synaptic signal propagating along a linear, one-dimensional, weakly active cable due to neuronal noise sources along the way, using both a signal reconstruction and a signal detection paradigm.

Here we begin such an analysis by quantitatively characterizing three sources of membrane noise: (1) thermal noise due to the passive membrane resistance, (2) noise due to stochastic openings and closings of voltage-gated membrane channels (Na+ and K+), and (3) noise due to random, background synaptic activity. Using analytical expressions for the power spectral densities of these noise sources, we compare their magnitudes in the case of a patch of membrane from a cortical pyramidal cell and explore their dependence on different biophysical parameters.
Testbed Evaluation of Virtual Environment Interaction Techniques
Authors: Bowman Doug A. , Johnson Donald B. , Hodges Larry F.
Published: July 2002

As immersive virtual environment (VE) applications become more complex, it is clear that we need a firm understanding of the principles of VE interaction. In particular, designers need guidance in choosing three-dimensional interaction techniques. In this paper, we present a systematic approach, testbed evaluation, for the assessment of interaction techniques for VEs. Testbed evaluation uses formal frameworks and formal experiments with multiple independent and dependent variables to obtain a wide range of performance data for VE interaction techniques. We present two testbed experiments, covering techniques for the common VE tasks of travel and object selection/manipulation. The results of these experiments allow us to form general guidelines for VE interaction and to provide an empirical basis for choosing interaction techniques in VE applications. Evaluation of a real-world VE system based on the testbed results indicates that this approach can produce substantial improvements in usability.
A Brief History of Stigmergy
Authors: Theraulaz Guy , Bonabeau Eric
Published: July 2002

Stigmergy is a class of mechanisms that mediate animal-animal interactions. Its introduction in 1959 by Pierre-Paul Grassé made it possible to explain what had been until then considered paradoxical observations: In an insect society individuals work as if they were alone while their collective activities appear to be coordinated. In this article we describe the history of stigmergy in the context of social insects and discuss the general properties of two distinct stigmergic mechanisms: quantitative stigmergy and qualitative stigmergy.
Decomposition Analysis of Finnish Material Flows: 1960–1996
Authors: Hoffrén Jukka , Luukkanen Jyrki , Kaivo‐oja Jari
Published: July 2002

To the extent that environmental impacts are the consequence of the magnitude of total material input into production in an economy, they can be lessened by reducing the use of materials—by concentrating on what has been called qualitative growth. This article presents a summary of Finnish resource use over the period 1960–1996 as a means of evaluating the trends in material use and providing a basis for assessments of sustainability. It adapts the technique of decomposition analysis developed in the field of energy studies to distinguish the effects of changes in aggregate economic activity (“activity effect”), composition of industrial activity (“structural effect”) and materials intensity of use (“intensity effect”) on a sectoral basis.p

According to the analysis presented here, materials consumption in Finland has grown substantially between 1960 and 1996 in the electricity, gas and water supply, pulp and paper production, civil engineering, and mining and quarrying sectors. In the same period, the ratio of GDP/mass of material mobilized has improved by 175 percent. Economic growth has caused the largest increases in materials use in the building of infrastructures; for example roads, waterways, means of supplying electricity, gas, and water, and in the production of paper and paper products. The least growth took place in the transport, basic metals production, and mining and quarrying sectors.
Energy Efficiency and Structural Change in the Netherlands, 1980–1995
Authors: Farla Jacco C. M. , Blok Kornelis
Published: July 2002

International agreement has been reached to reduce greenhouse gas emissions worldwide. One important way of decoupling CO2 emissions from economic growth is by introducing technical measures to improve energy efficiency. In this article, we assess the influence of developments in energy efficiency and economic structure on the total primary energy consumption in the Netherlands over the period 1980– 1995. We find a distinct decoupling of the economic growth and energy consumption of 1.5% per year in the 15‐year analysis period. We measure (technical) changes in energy efficiency by changes in the energy consumption per physical unit of production or activity. The aggregate rate of (technical) energy‐efficiency improvement was 1.4% per year over the period 1980–1995. The use of physical production indicators makes it possible to measure energy‐efficiency developments without detailed surveys at a very low level of aggregation. When we look at economic structural changes over this period, we find that (i) no substantial shift took place at the level of the economic sectors that we distinguish; (ii) the most energy intensive subsectors grew much faster than the total economy; and (iii) at the subsector level, on average, a sizable decoupling of physical production and value added occurred. We conclude that structural changes, that is, changes in the composition of the economy, did not lead to a net decrease in the energy intensity of the Netherlands over the period 1980–1995.
Pet Attachment and Dissociation
Authors: Brown Sue-Ellen , Katcher Aaron
Published: July 2002

This study replicated the co-existence of dissociation and pet attachment in 113 female veterinary technician students based on a bivariate correlation analysis and chi-square analysis of their responses to the 28-question Dissociative Experiences Scale and an eight-question "pet" attachment questionnaire.The study replicated the positive correlation between pet attachment and dissociation first reported by Brown & Katcher (1997). Also replicated was the finding that significantly more with the highest pet attachment had clinical levels of dissociation than did those with lower attachment. Results compared to a meta-analytic study found their level of dissociation to be higher than participants in non-animalrelated categories.This study suggests that dissociation may characterize one subset of people highly attached to pets and discusses implications for companion animal research and individuals in animal-related careers.
BETWEEN POPULATIONS OF REED WARBLERS IN DEFENCES AGAINST BROOD PARASITISM
Authors: Lindholm Anna , Thomas Robert
Published: July 2002

Two potential defences against brood parasitism by the cuckoo Cuculus canorus were compared experimentally between British populations of reed warblers Acrocephalus scirpaceus that are parasitised at different rates. (1) Rates of rejection of model cuckoo eggs were lower at two unparasitised populations which did not have resident cuckoos, than at a rarely parasitised population which had cuckoos nearby, and at a regularly parasitised population. (2) Reed warblers from an unparasitised population showed a slightly weaker response to taxidermic mounts of cuckoos and, unlike a parasitised population, did not differentiate between mounts of a cuckoo, sparrowhawk Accipiter nisus and jay Garrulus glandarius . Differences in exposure to real predators may explain the differences in responses to mounted predators between populations, as specific aggressive responses to predators are likely to have been learned. Although evidence from dispersal and population turnover data suggests that there is likely to be gene flow between reed warbler populations in Britain, the hypothesis that the population differences reflect genotypic differences could not be ruled out. An alternative explanation of phenotypic plasticity in defences could also explain the population differences. Phenotypic plasticity in defences would be favoured in environments where the risk of parasitism fluctuates, if those defences are costly to unparasitised reed warblers.
THE ROLE OF FAMILIARITY IN THE DEVELOPMENT OF SOCIAL RECOGNITION BY LAMBS
Authors: Porter Richard , Désiré Lara , Bon Richard , Orgeur Pierre
Published: July 2002

A series of experiments investigated the role of association and familiarity in the development of social recognition among lambs. In each experiment, lambs were tested successively with 2 different social partners. When separated from their mothers, lambs that were paired with a partner with which they had been housed for 17 or 5 days emitted fewer distress bleats than they did during tests with an unfamiliar lamb. However, this effect was only evident when the test with the unfamiliar partner preceded the test with the familiar partner. When lambs were first tested with an unfamiliar partner treated with the same artificial odorant that had previously been associated with members of their own group, they bleated more than they did during a second test with a partner whose odor was novel. This effect was not observed when the familiar- and novel-odor partners were encountered in the reverse order. Bleating frequencies by lambs paired with their twin did not differ reliably from those of lambs paired with a familiar non-twin. Nonetheless, there was a signficant correlation between the number of bleats by twins that were tested together. Overall, the results indicate that lambs become familiar with and recognize individuals (twins and non-twins) as a result of direct association. Lambs also discriminate between novel scents and artificial odorants associated with their familiar agemates, but such odors neither mask nor substitute effectively for lambs' individually recognizable phenotypes. Bleating frequency increases with the novelty of the social partner and of the test situation, and is therefore markedly affected by repeated testing.
SPERMATOPHORE SIZE AND MULTIPLE MATING: EFFECTS ON REPRODUCTIVE SUCCESS AND POST-MATING BEHAVIOUR IN THE INDIAN MEAL MOTH
Authors: Ryne Camilla , Zhu Jun-Wei , Van Dongen Stefan , Löfstedt Christer
Published: July 2002

Ensuring fatherhood is an important issue in polygamous species. In many lepidopteran species, the male inserts a large package (spermatophore) consisting of sperm, accessory gland fluids and nutrients into the female's bursa copulatrix during copulation. In most species it has been shown that a large male donation causes females either to stop calling, or to prolong the time until re-mating, hereby ensuring fatherhood. We investigated the changes in size of the donation in multiple mating and how the size affected the female post mating behaviour in the Indian meal moth, Plodia interpunctella. In concordance with other previous studies, we found that a male inserted a significantly larger donation during the first mating compared to following mating occasions. The larger donation was not coupled with larval output since it did not decline during mating occasions. Some males were able to mate at least eight times and male fitness, counted as larval output, showed no association with sequence of mating number. Even though females received larger donations during the first mating, there was no effect on female post mating behaviour in terms of pheromone production and calling behaviour. The weight of the mated female's bursa copulatrix decreased linearly over the first eight days after mating, suggesting that females absorb material other than sperm. We discuss the female advantage of receiving a large donation and why males invest more energy into the first mating while female post-mating behaviour is not affected.
OPTIMAL TERRITORY SIZE IN THE CONVICT CICHLID
Authors: Praw Jason , Grant James W.A.
Published: July 2002

Models of optimal territory size are usually tested only by demonstrating that territory size is inversely related to food abundance or intruder number. The most fundamental predictions of the models, however, have rarely been tested: i.e. the fitness of the defender is a function of territory size and the optimal territory is one of intermediate size. We tested these predictions by measuring the growth rate of large convict cichlids (Archocentrus nigrofasciatus, formerly Cichlasoma nigrofasciatum) while defending food patches against smaller intruders over a 10-day period. Food patches differed in area by more than two orders of magnitude. We manipulated food abundance so that it increased with patch size in a decelerating way. As assumed, the realized benefits of defence (weight of food eaten by the defender) and the costs of defence (chase rate and chase radius) both increased in a decelerating way with increasing patch area. As predicted, the growth rate of the defender first increased and then decreased with increasing patch size. The initial increase in defender growth rate with increasing patch size was related to an increase in food eaten, but the decrease in growth rate for fish defending the largest patches was related to the costs of defence. Fish defending large patches had a low growth efficiency, apparently because of the social stress caused by intruders in their territories. Taken together, these results support the assumptions and predictions of optimal territory size models.
SOCIAL BONDS AND GENETIC TIES: KINSHIP, ASSOCIATION AND AFFILIATION IN A COMMUNITY OF BONOBOS (PAN PANISCUS)
Authors: Hohmann  , Gerloff  , Tautz  , Fruth
Published: July 2002

Studies of captive populations of bonobos suggest that females are more gregarious than males. This seems to contradict assumed sex-differences in kinship deriving from a species-typical dispersal pattern of female exogamy and male philopatry. Here we present data on spatial associations and affiliative relations among members of one wild community (Eyengo) for which genetic relationships were identified by analysing mitochondrial and nuclear DNA. Our data from Lomako confirm the existence of spatial associations among resident females. In addition, they reveal strong social bonds between males and females. While most female-female associations did not last longer than one field season, long-term associations occurred predominantly between mixed-sex dyads and involved both close kin and unrelated individuals. Differences in social grooming appeared to be related to patterns of spatial association rather than to kinship. It is suggested that under natural conditions social organisation of bonobos is characterised by strong inter-sexual bonds. Males may benefit from bonding with females by increased reproductive success via rank acquisition. For females benefits may derive from inclusive fitness and reduced food competition. Preliminary evidence suggests that females also may benefit from protection by resident males against male intruders.
Redescription of Diplogasteroides nasuensis Takaki, 1941 and D. magnus Völk, 1950 (Nematoda: Diplogastrina) associated with Scarabaeidae (Coleoptera)
Authors: Sudhaus Walter , Kiontke Karin , Manegold Albrecht
Published: July 2002

A detailed morphological description is presented of Diplogasteroides nasuensis Takaki, 1941 and D. magnus Völk, 1950, using light and scanning electron microscopy. Neoaplectana melolonthae Weiser, 1958 and Diplogasteroides (Rhabdontolaimus) berwigi Rühm, 1959 are synonymised with D. nasuensis. This gonochoristic species is distinguished from the hermaphroditic D. magnus by the dorsal metastomal decoration which consists of bristle-like protrusions instead of a more or less uniform tooth. The spermatocytes in D. nasuensis are twice as big as those in hermaphrodites of D. magnus. Dauer juveniles of D. nasuensis are considerably bigger than those of D. magnus. Dauer juveniles of both species are present on wood cockchafer (Melolontha hippocastani) larvae and adults but, on adult beetles, D. nasuensis dauer juveniles enter the genital pouch, whereas those of D. magnus are found under the hind coxae. In Germany, D. nasuensis is found only on M. hippocastani. D. magnus dauer juveniles are also found on a variety of other Scarabaeidae. Further small differences distinguish the two species. The genus Diplogasteroides is proposed to be taken in a broad sense. Several genera names are synonymised with Diplogasteroides.
Increase in 14C-carbon translocation to the soil microbial biomass when five species of plant-parasitic nematodes infect roots of white clover
Authors: Yeates Gregor W. , Saggar Surinder , Hedley Carolyn B. , Mercer Chris F.
Published: July 2002

Clonal white clover growing in pots was inoculated with Heterodera trifolii,
Meloidogyne hapla, Meloidogyne trifoliophila, Pratylenchus sp., or Xiphinema
diversicaudatum, pulse-labelled with 14C and after 15 days the distribution
of 14C in compartments of the soil: plant: nematode system determined.
Nematode inoculation had no effect on shoot, root and soil microbial
biomasses, but the nematode treatments significantly affected the
distribution of 14C in these compartments. The greatest translocation of 14C
to the soil was in pots with X. diversicaudatum, M. hapla or M.
trifoliophila. The percentage of 14C in the microbial biomass varied
significantly, being highest with X. diversicaudatum and Pratylenchus sp.,
and lowest in control pots. Nematodes of all species from the soil
consistently had lower specific activity than those from roots. It has now
been demonstrated for a range of nematodes and soils that nematode infection
increases translocation of photosynthate to soil microbial biomass. As the
soil microbial biomass plays a critical role in the availability of plant
nutrients it appears that low infections of plant-parasitic nematodes may
lead to greater availability of plant nutrients. Anstieg der Verlagerung von
14C-Kohlenstoff in die mikrobielle Biomasse, wenn funf Arten
pflanzenschadigender Nematoden Wurzeln von Weissklee befallen - In Topfen
gehaltene Weisskleeklone wurden mit Heterodera trifolii, Meloidogyne hapla,
Meloidogyne trifoliophila, Pratylenchus sp. oder Xiphinema diversicaudatum
infiziert. Die Nematoden waren mit 14C markiert, und nach 15 Tagen wurde die
Verteilung des 14C in Abschnitten des Systems Boden: Pflanze: Nematode
bestimmt. Nematodenbefall hatte zwar keine Wirkung auf die Biomassen von
Spross, Wurzel und Mikroben, doch beeinflusste die Behandlung mit Nematoden
signifikant die Verteilung von 14C in diesen Abschnitten. Die grosste
Verlagerung von 14C in den Boden fand in den Topfen mit X. diversicaudatum,
M. hapla oder M. trifoliophila statt. Der Anteil von 14C in der mikrobiellen
Biomasse variierte stark. Er war am hochsten in Topfen mit X.
diversicaudatum und Pratylenchus sp. und am gerigsten in den Kontrolltopfen.
Bei allen Arten hatten die Nematoden aus dem Boden durchweg eine geringere
spezifische Aktivitat als die aus den Wurzeln. Es wurde jetzt fur eine Reihe
von Nematoden und Boden gezeigt, dass Nematodenbefall die Verlagerung von
Photosyntheseprodukten in die mikrobielle Biomasse des Bodens steigert. Da
die mikrobielle Biomasse im Boden eine kritische Rolle bei der Verfugbarkeit
von Pflanzennahrstoffen spielt, scheint es, dass geringer Befall durch
pflanzenschadigende Nematoden zu einer grosseren Verfugbarkeit von
Pflanzennahrstoffen fuhren kann.
Paratylenchinae: postembryonic developmental stages of Paratylenchus straeleni (De Coninck, 1931) and P. steineri Golden, 1961 (Nematoda: Tylenchulidae)
Authors: Brzeski Michal , Hanel Ladislav
Published: July 2002

Postembryonic developmental stages of naturally occurring populations of Paratylenchus straeleni and P. steineri were studied. In the former species all juveniles had a well developed stylet and pharynx, while the body of the 4th stage juveniles contained numerous dark granules and this is considered the resting stage. In P. steineri the stylet and pharynx were well developed in the 2nd and 3rd stage juvenile, but the 3rd stage juvenile had numerous granules in the body suggesting it is the resting stage. Fourth stage juveniles had no stylets and the pharynx is much reduced. Because some moulting females have the stylet cone of the juveniles being shed together with the juvenile cuticle, it is concluded that the 4th stage is short-lasting. The length of the body, pharynx, tail and genital primordium as well as the index b increases in successive developmental stages. Indices a, c, c' were almost constant in all juvenile stages. The resting juvenile stage characterises species and it should be included in species descriptions for better characterisation of Paratylenchus species. Paratylenchinae: stades de developpement de Paratylenchus straeleni (De Coninck, 1931) et P. steineri Golden, 1961 (Nematoda: Tylenchulidae) - Ont ete etudies les stades de developpement post-embryonnaire de populations sauvages de Paratylenchus straeleni et de P. steineri. Chez la premiere espece tous les juveniles ont un stylet et un pharynx bien developpes alors que le corps des juveniles de 4eme stade contient de nombreux granules fonces; ce stade a donc ete considere comme le stade de quiescence. Chez P. steineri, le stylet et le pharynx sont bien developpes chez le second et troisieme stades juveniles, mais ce dernier montre de nombreux granules a l'interieur du corps, suggerant qu'il constitue le stade de quiescence. Les juveniles de 4eme stade sont depourvus de stylet et le pharynx est tres reduit. Du fait que chez les femelles en train de muer le cone du stylet des juveniles est rejete avec la cuticule des juveniles, il a ete conclu que le 4eme stade n'a qu'une courte duree de vie. Les longueurs du corps, du pharynx, de la queue et du primordium genital de meme que l'index b augmentent en passant d'un stade a l'autre. Les indices a, c et c' sont generalement constants chez tous les stades juveniles. Le stade quiescent des juveniles est caracteristique de l'espece et devrait etre inclus dans les descriptions d'especes pour une meilleure caracterisation specifique des Paratylenchus.
First report of Bursaphelenchus xylophilus in Portugal and in Europe
Authors: Mota Manuel M. , Braasch Helen , Bravo Maria Antonia , Penas Ana Catarina , Burgermeister Wolfgang , Metge Kai , Sousa Edmundo
Published: July 2002

A survey of aphelenchid nematodes (Nematoda: Aphelenchida) associated with maritime pine, Pinus pinaster, was conducted in Portugal in 1996 and 1999. A Bursaphelenchus species has been identified for the first time in the Iberian Peninsula. B. xylophilus is reported for the first time in Europe. It was found in very high numbers - up to 38 000 per 10 g of pine wood - inside a few declining trees infested with curculionid, cerambycid and scolytid beetles. Morphological observations, including shape of spicules, bursa, vulva, female tail end and stylet as well as morphometrics, were in accordance with the species description. Species-specific DNA fragment patterns were obtained using ITS-RFLP analysis, with five different restriction enzymes. The importance and implications of this finding are discussed. Premiere signalisation de Bursaphelenchus xylophilus au Portugal, at en Europe - Une enquete sur les nematodes Aphelenchides (Nematoda: Aphelenchida) associes au pin maritime (Pinus pinaster) a ete realisee au Portugal de 1996 a 1999. Une espece de Bursaphelenchus a ete identifiee pour la premiere fois dans la Peninsule Iberique. B. xylophilus est signale pour la premiere fois en Europe. Il a ete trouve en tres grand nombre - jusqu'a 38 000 individus pour 10 g de bois de pin - dans des arbres deperissants infestes par des Coleopteres Curculionides, Cerambycides et Scolytides. Les observations concernant la morphologie - en particulier la forme des spicules, la bourse, la vulve, l'extremite de la queue de la femelle et le stylet - de meme que les donnees morphometriques correspondent a la description de l'espece. Des sequences de fragments d'ADN specifique de l'espece ont ete obtenus par analyse ITS-RFLP a l'aide de cinq enzymes de restriction. L'importance et les implications de cette decouverte sont discutees.
Kaolinite-to-dickite reaction in sandstone reservoirs
Authors: Beaufort D. , Cassagnabere A. , Petit S. , Lanson B. , Berger G. , Lacharpagne J. C. , Johansen H.
Published: July 2002

The SEM, XRD, FFIR and DTA analyses of different size-fractions of clay material from sandstone reservoirs which have experienced a large range of burial conditions have been used to examine the different steps of the depth-related kaolinite-dickite reaction. Dickite progressively replaced kaolinite within a range of burial depths estimated between about 2500 m and 5000 m. The kaolinite-to-dickite reaction proceeds by gradual structural changes concomitant to crystal coarsening and change from booklet to blocky morphology. The crystallization of dickite proceeds by two distinct paths: (1) Accretion of new material from either dissolution of smaller unstable kaolinite crystals and/or detrital minerals (chiefly feldspars), on early-formed coarser metastable kaolinite crystals which exert extended morphological control on the growing crystals. (2) Neoformation of ordered dickite which will continue to grow by a dissolution-crystallization process. The kaolinite-todickite reaction is kinetically controlled and anomalies in the kaolinite/dickite ratio observed in certain sandstone reservoirs may be used to assess the timing of invasion by hydrocarbons.
Carbonatite lapilli-bearing tuff and a dolomite carbonatite bomb from Murumuli crater, Katwe volcanic field, Uganda
Authors: Stoppa F. , Woolley A. R. , Lloyd F. E. , Eby N.
Published: July 2002

A group of carbonate-rich tuffs are described from the Murumuli crater, Katwe-Kikorongo volcanic field, SW Uganda which contain abundant carbonatite pelletal lapilli, together with melilitite lapilli and a range of xenocrysts and lithic fragments including clinopyroxenites considered to be of mantle origin. The carbonatite lapilli consist essentially of Sr-bearing calcite and Mg-calcite which form quench-textured laths. The lapilli contain microphenocrysts of Ti-magnetite, perovskite, apatite, clinopyroxene, sanidine and altered prisms of melilite. A 7 cm long dolomite carbonatite bomb is described which displays a form typically assumed by lava clots erupted in a molten state. Chemical analyses of a tuff, the bomb and a range of minerals are presented. Carbonatite clearly played an important role in the Katwe-Kikorongo magmatism and it is suggested that carbonatite magma evolved from carbonate-bearing melilitite.
A cobaltite-framboidal pyrite association from the Kupferschiefer: possible
implications for trace element behaviour during the earliest stages of
diagenesis
Authors: Large D. J. , Sawłowicz Z. , Spratt J.
Published: July 2002

Cobaltite-cemented pyrite framboids are reported from the base of the
Kupferschiefer in the Lubin-Sieroszowice mining district in southern Poland. In
the framboids, cobaltite occurs interstitial to the pyrite crystals. The
cobaltite-cemented framboids are confined to within a few cm either side of the
boundary between the Weissliegendes sandstone and the Kupferschiefer laminated
organic-rich shales. Textural relations and distribution of the cobaltite is
interpreted as indicating that the framboids acted as a site of preferred
cobaltite precipitation and that the cobaltite precipitated in response to the
changing chemical environment at the Weissliegendes/Kupferschiefer contact. It is
proposed that the texture may have formed as a result of desorption of Co and/or
As which had been adsorbed onto the monosulphide precursors to the framboidal
pyrite. Desorption during the transition to pyrite resulted in cobaltite
saturation within the framboid and subsequent precipitation. The source of the Co
and As was probably oxyhydroxides which exist in the upper oxic part of the
Weissliegendes.
Protein kinase C–catalyzed phosphorylation of an inhibitory phosphoprotein of myosin phosphatase is involved in human platelet secretion
Authors: Watanabe Yasuyuki , Ito Masaaki , Kataoka Yoshiyuki , Wada Hideo , Koyama Mutsumi , Feng Jianhua , Shiku Hiroshi , Nishikawa Masakatsu
Published: July 2002

Protein kinase C (PKC)–potentiated inhibitory phosphoprotein of myosin phosphatase (CPI) was detected in human platelets. Like smooth muscle CPI-17, in vitro phosphorylation of platelet CPI by PKC inhibited the activity of myosin phosphatase containing the PP1δ catalytic subunit and the 130-kd myosin-binding subunit (MBS). Treatment of intact platelets with thrombin or the stable thromboxane A2 analog STA2 resulted in increased phosphorylation of both CPI and MBS at Thr-696, whereas phorbol myristate acetate (PMA) and the Ca++ ionophore ionomycin only induced CPI phosphorylation. PMA induced slow adenosine triphosphate (ATP) secretion of fura 2–loaded platelets with no change in cytosolic Ca++. The PMA-induced increase in CPI phosphorylation preceded phosphorylation of 20-kd myosin light chain (MLC20) at Ser-19 and ATP secretion. The PKC inhibitor, GF109203X, inhibited PMA-induced phosphorylation of CPI and MLC20 with similar IC50 values. These findings suggest that the activation of PKC by PMA induces MLC20phosphorylation by inhibiting myosin phosphatase through phosphorylation of CPI. STA2-induced MLC20phosphorylation was also diminished but not abolished by GF109203X, even at high concentrations that completely inhibited STA2-induced CPI phosphorylation. A combination of the Rho-kinase inhibitor Y-27632 and GF109203X led to a further decrease in STA2-induced MLC20 phosphorylation, mainly because of a significant inhibition of MBS phosphorylation at Thr-696. Inhibition of STA2-induced ATP release by Y-27632, GF109203X, or both appeared to correlate with the extent of MLC20 phosphorylation. Thus, CPI phosphorylation by PKC may participate in inhibiting myosin phosphatase, in addition to the Rho-kinase–mediated regulation of myosin phosphatase, during agonist-induced platelet secretion.
Prognostic significance of tumor burden in the blood of patients with erythrodermic primary cutaneous T-cell lymphoma
Authors: Scarisbrick Julia J. , Whittaker Sean , Evans Alun V. , Fraser-Andrews Elisabeth A. , Child Fiona J. , Dean Alan , Russell-Jones Robin
Published: July 2002

Erythrodermic cutaneous T-cell lymphoma (CTCL) includes patients with erythrodermic mycosis fungoides who may or may not exhibit blood involvement and Sézary syndrome and in whom hematological involvement is, by definition, present at diagnosis. These patients were stratified into 5 hematologic stages (H0-H4) by measuring blood tumor burden, and these data were correlated with survival. The study identified 57 patients: 3 had no evidence of hematologic involvement (H0), 8 had a peripheral blood T-cell clone detected by polymerase chain reaction (PCR) analysis of the T-cell receptor gene and less than 5% Sézary cells on peripheral blood smear (H1), and 14 had either a T-cell clone detected by Southern blot analysis or PCR positivity with more than 5% circulating Sézary cells (H2). Twenty-four patients had absolute Sézary counts of more than 1 × 109 cells per liter (H3), and 8 patients had counts in excess of 10 × 109 cells per liter (H4). The disease-specific death rate was higher with increasing hematologic stage, after correcting for age at diagnosis. A univariate analysis of 30 patients with defined lymph node stage found hematologic stage (P = .045) and lymph node stage (P = .013) but not age (P = .136) to be poor prognostic indicators of survival. Multivariate analysis identified only lymph node stage to be prognostically important, although likelihood ratio tests indicated that hematologic stage provides additional information (P = .035). Increasing tumor burden in blood and lymph nodes of patients with erythrodermic CTCL was associated with a worse prognosis.The data imply that a hematologic staging system could complement existing tumor-node-metastasis staging criteria in erythrodermic CTCL.
Desferrioxamine-chelatable iron, a component of serum non–transferrin-bound iron, used for assessing chelation therapy
Authors: Breuer William , Ermers Marieke J. J. , Pootrakul Pensri , Abramov Ayala , Hershko Chaim , Cabantchik Z. Ioav
Published: July 2002

This study introduces a method for monitoring a component of serum non–transferrin-bound iron (NTBI), termed “desferrioxamine-chelatable iron” (DCI). It is measured with the probe fluorescein-desferrioxamine (Fl-DFO), whose fluorescence is stoichiometrically quenched by iron. DCI was found in the serum of most patients with thalassemia major (21 of 27 tested, range 1.5-8.6 μM), but only in a minority of patients with hereditary hemochromatosis (8 of 95 samples from 39 patients, range 0.4- 1.1 μM) and in none of 48 controls. The method was applied to monitoring the appearance of iron in the serum of patients under chelation therapy. Short-term (2 hours) follow-up of patients immediately after oral administration of deferriprone (L1) showed substantial mobilization of DCI into the serum (up to10 μM within 30-60 minutes). The transfer of DCI from L1 to Fl-DFO was observed in vitro with preformed L1-iron complexes, and occurred even at L1/iron ratios exceeding 3:1. Simultaneous administration of oral L1 and intravenous DFO to patients abrogated the L1-mediated rise in DCI, consistent with the shuttling of iron from L1 to DFO in vivo. A similar iron transfer from L1 to apo-transferrin was observed in vitro, lending experimental support to the notion that L1 can shuttle iron in vivo to other high-affinity ligands. These results provide a rationale for using chelator combinations, with the highly permeant L1 acting as an intracellular chelator-shuttle and the less permeant DFO serving as an extracellular iron sink. Potential applications of the DCI assay may be for studying chelator action and as an index of patient chelation status.
Hemophagocytic lymphohistiocytosis due to germline mutations inSH2D1A, the X-linked lymphoproliferative disease gene
Authors: Arico Maurizio , Imashuku Shinsaku , Clementi Rita , Hibi Shigeyoshi , Teramura Tomoko , Danesino Cesare , Haber Daniel A. , Nichols Kim E.
Published: July 2002

The hemophagocytic lymphohistiocytoses (HLH) comprise a heterogeneous group of disorders characterized by dysregulated activation of T cells and macrophages. Although some patients with HLH harbor perforin gene mutations, the cause of the remaining cases is not known. The phenotype of HLH bears a strong resemblance to X-linked lymphoproliferative disease (XLP), an Epstein-Barr virus (EBV)-associated immunodeficiency resulting from defects in SH2D1A, a small SH2 domain-containing protein expressed in T lymphocytes and natural killer cells. Here it is shown that 4 of 25 male patients with HLH who were examined harbored germline SH2D1A mutations. Among these 4 patients, only 2 had family histories consistent with XLP. On the basis of these findings, it is suggested that all male patients with EBV-associated hemophagocytosis be screened for mutations in SH2D1A. Patients identified as having XLP should undergo genetic counseling, and be followed long-term for development of lymphoma and hypogammaglobulinemia.