bluuebunny/crossref_metadata_2025 huggingface dataset:
A Parallel Noise-Robust Algorithm to Recover Depth Information from Radial Flow Fields
Authors: Wörgötter F. , Cozzi A. , Gerdes V.
Published: July 2002

A parallel algorithm operating on the units (“neurons”) of an artificial retina is proposed to recover depth information in a visual scene from radial flow fields induced by ego motion along a given axis. The system consists of up to 600 radii with fewer than 65 radially arranged neurons on each radius. Neurons are connected only to their nearest neighbors, and they are excited as soon as a sufficiently strong gray-level change occurs. The time difference of two subsequently activated neurons is then used by the last-excited neuron to compute the depth information. All algorithmic calculations remain strictly local, and information is exchanged only between adjacent active neurons (except for the final read-out). This, in principle, permits parallel implementation. Furthermore, it is demonstrated that the calculation of the object coordinates requires only a single multiplication with a constant, which is dependent on only the retinal position of the active neuron. The initial restriction to local operations makes the algorithm very noise sensitive. In order to solve this problem, a prediction mechanism is introduced. After an object coordinate has been determined, the active neuron computes the time when the next neuronal excitation should take place. This estimated time is transferred to the respective next neuron, which will wait for this excitation only within a certain time window. If the excitation fails to arrive within this window, the previously computed object coordinate is regarded as noisy and discarded. We will show that this predictive mechanism relies also on only a (second) single multiplication with another neuron-dependent constant. Thus, computational complexity remains low, and noisy depth coordinates are efficiently eliminated. Thus, the algorithm is very fast and operates in real time on 128×128 images even in a serial implementation on a relatively slow computer. The algorithm is tested on scenes of growing complexity, and a detailed error analysis is provided showing that the depth error remains very low in most cases. A comparison to standard flow-field analysis shows that our algorithm outperforms the older method by far. The analysis of the algorithm also shows that it is generally applicable despite its restrictions, because it is fast and accurate enough such that a complete depth percept can be composed from radial flow field segments. Finally, we suggest how to generalize the algorithm, waiving the restriction of radial flow.
The Cultural Role and Communicative Properties of Scientifically Derived Compositional Theories
Authors: Tanzi Dante
Published: July 2002

The role of science in the processes of musical creation is justifiable as a method of formalizing knowledge used for expressive purposes. The understanding of musical phenomena, however, should not be reduced to cognitive aspects or entrusted to a purely descriptive iteration; certain creative functions of musical composition go beyond the many degrees of control offered by the technologies of knowledge. The necessity of comparison with the cultural orientation of an audience, sometimes considered secondary by some, must remain integral. Our interest in qualitatively new creative and intellectual acts must not abandon the dialectical character of musical communication, which involves, among other things, a shared linguistic universe.
Visual Touch in Virtual Environments: An Exploratory Study of Presence, Multimodal Interfaces, and Cross-Modal Sensory Illusions
Authors: Biocca Frank , Kim Jin , Choi Yung
Published: July 2002

How do users generate an illusion of presence in a rich and consistent virtual environment from an impoverished, incomplete, and often inconsistent set of sensory cues? We conducted an experiment to explore how multimodal perceptual cues are integrated into a coherent experience of virtual objects and spaces. Specifically, we explored whether inter-modal integration contributes to generating the illusion of presence in virtual environments.

To discover whether intermodal integration might play a role in presence, we looked for evidence of intermodal integration in the form of cross-modal interactions—perceptual illusions in which users use sensory cues in one modality to “fill in” the “missing” components of perceptual experience. One form of cross-modal interaction, a cross-modal transfer, is defined as a form of synesthesia, that is, a perceptual illusion in which stimulation to a sensory modality connected to the interface (such as the visual modality) is accompanied by perceived stimulation to an unconnected sensory modality that receives no apparent stimulation from the virtual environment (such as the haptic modality). Users of our experimental virtual environment who manipulated the visual analog of a physical force, a virtual spring, reported haptic sensations of “physical resistance”, even though the interface included no haptic displays. A path model of the data suggested that this cross-modal illusion was correlated with and dependent upon the sensation of spatial and sensory presence.

We conclude that this is evidence that presence may derive from the process of multi-modal integration and, therefore, may be associated with other illusions, such as cross-modal transfers, that result from the process of creating a coherent mental model of the space. Finally, we suggest that this perceptual phenomenon might be used to improve user experiences with multimodal interfaces, specifically by supporting limited sensory displays (such as haptic displays) with appropriate synesthetic stimulation to other sensory modalities (such as visual and auditory analogs of haptic forces).
TOADS: A Two-Dimensional Open-Ended Architectural Database System
Authors: Madden Samuel , Wiegand Thomas E. von
Published: July 2002

The TOADS system is an innovative tool for building interior-space virtual environments (VEs) in two dimensions. Existing VE design tools typically operate in three dimensions, which makes it difficult to manipulate objects on the inherently two-dimensional computer screen. TOADS allows nearly the same functionality as those three-dimensional systems in an easy-to-use, two-dimensional environment. Users edit and enhance DXF floorplans with height and texture information. The software includes an inference engine that automatically identifies doors in the floorplan and generates openable polygons in the final environment. It also includes a sophisticated mechanism for embedding complex textures, such as transparent windows, at arbitrary heights in wall polygons. The entire interface is integrated with software that drives a custom texture-acquisition device. This device consists of a rack-mounted camera that captures narrow bands of textures and tiles them together to form long, continuous swaths of texture. This paper summarizes these tools and their function, and presents examples of environments that were generated with them.
Multimedia Human-Computer Interaction for Presence and Exploration in a Telemuseum
Authors: Agah Arvin , Tanie Kazuo
Published: July 2002

It is not always feasible or practical to be present at a location of interest. Telepresence makes such possible. This paper presents the design and implementation of a telepresence system in which a mobile manipulator robot is utilized to explore a museum at a remote site, sending live video and audio on demand to a user at the local site. The user's sense of presence is also enhanced through the capability to manipulate objects remotely via the robot's gripper. The display system is a slightly modified, off-the-shelf mediascope, a television display system that can be worn like a pair of glasses. The head movements of the user are monitored using color tracking, and the displayed images are updated according to the motions of the head. This is achieved by interpreting the human head movements and transforming them into control signals for appropriate movements of the robot and its mounted color camera. Novel features of the presented system include utilization of human implicit commands, availability and cost-effectiveness of the system, feeling of presence, and intelligence fusion of the human user (where to go and what to do) with the robot's intelligence (local obstacle avoidance and navigation). The multimedia interface and control of the system are described in detail. Additionally, a number of research issues that require further investigation in order to realize attainable, high fidelity telepresence systems are discussed in this paper.
Patenting Biodiversity? Rejecting WTO/TRIPS in Southern Africa
Authors: Mushita Andrew T. , Thompson Carol B.
Published: July 2002

The year 2000 was the deadline for developing countries to bring their national laws into compliance with the trade-related intellectual property rights (TRIPS) agreement under the World Trade Organization (WTO). However, the transition to one universal intellectual property law is not proceeding as scripted. After briefly summarizing a long tradition of debate about intellectual property, this article first analyzes what is new and different about TRIPS. It then argues that extending intellectual private property rights to plants, in particular in the form of patents, challenges scientific logic and threatens biodiversity. Southern Africa has also taken this view, and is proposing political and legal alternatives to the patenting of biodiversity. Combining principles from the Convention on Bio logical Diversity and the FAO International Undertaking on Plant Genetic Resources, draft legislation affirms farmers' and community rights, while not denying the important role of international protocols. The proposal, calling for local and national control, is not only a model for Africa, but for other developing countries to resolve the incongruities between TRIPS and the CBD over the patenting of living organisms.
SIGNIFYING BODIES: THE CULTURAL SIGNIFICANCE OF SUICIDE WRITINGS BY WOMEN IN MING-QING CHINA
Authors: Fong Grace
Published: July 2002

This paper examines the form, content, and cultural significance of poems written by a number of otherwise unknown women before they committed suicide. The specific conditions under which these inscriptions are produced are disorder or violence in various forms, whether cultural, social, or familial, that threaten the integrity of the female body. The suicide poems are often accompanied by a short autobiographical preface. The author argues that this act of self-inscription at the moment of death is an act of agency. Through this textual production, the women reproduce a peculiarly Chinese sense of embodiment in inscription, and as selfrecorders, they write themselves into history. These women construct the integrity of their bodies in/out of disorder by textualizing and transforming them into cultural bodies inscribed with value and order.
Sorting is not Categorization: A Critique of the Claim that Brazilians Have Fuzzy Racial Categories
Authors: Gil-White Francisco
Published: July 2002

As a result of a spate of studies geared to investigating Brazilian racial categories, it is now believed by many that Brazilians reason about race in a manner quite different to that of Americans. This paper will argue that this conclusion is premature, as the studies in question have not, in fact, investigated Brazilian categories. What they have done is elicit sorting tasks on the basis of appearances, but the cognitive models of respondents have not been investigated in order to determine what are the boundaries of their concepts. Sorting based on appearances is not sufficient to infer the boundaries of concepts whenever appearance is not a defining criterion for the concepts in question, as the case appears to be for racial and ethnic categories. Following a critique of the methods used, I review a terminological and theoretical confusion concerning the use of the terms 'emic' and 'etic' in anthropology that appears directly responsible for the failure so far to choose methods appropriate to parsing the conceptual domain of 'race' in Brazil.
Evidence for the induction of interference competition between anuran larvae in plastic pond cages
Authors: Baker Gillian , Beebee Trevor J.C.
Published: July 2002

We recently showed that growth inhibition of Bufo bufo larvae by those of Rana temporaria in garden ponds only occurred when the larvae were confined in plastic cages. We therefore carried out further experiments to investigate the mechanism of this growth inhibition. Bufo bufo larvae were raised in mesh cages, plastic cages or plastic cages with supplementary food either alone or in the presence of R. temporaria. Three lines of evidence suggested that competition in the plastic cages had an interference component: firstly, growth inhibition of B. bufo by R. temporaria was only seen in plastic cages despite the fact that these cages supported normal growth rates of B. bufo in the absence of R. temporaria; secondly, food supplementation in plastic cages did not reduce the extent of B. bufo growth inhibition; and thirdly Anurofeca (= Prototheca) richardsi production was high in plastic cages but not in other treatments and correlated negatively with subsequent B. bufo larval growth. Plastic cages supported a different trophic web from other treatments and biotic factors seem the most likely regulators of A. richardsi abundance in these pools.
Lingually mediated discrimination of prey, but not plant chemicals, by the Central American anguid lizard, Mesaspis moreletii
Authors: Habegger Jason , Cooper William
Published: July 2002

The ability of the anguid lizard Mesaspis moreletii to identify food using only chemical cues was tested experimentally by presenting a series of chemical stimuli to lizards on the cotton tips of wooden applicators. The lizards responded much more strongly to cricket surface chemicals than to surface chemicals from romaine lettuce, diluted cologne (pungency control), and deionized water (odorless control). In a second experiment, there were no significant differences among conditions in tongue-flicks, tongue-flick attack scores, or number of individuals that bit swabs bearing stimuli from banana, white grape, dandelion, or deionized water. The absence of differential responses was not due to habituation because individuals tested again with cricket stimuli immediately after experiment two all bit the swabs. In the laboratory the lizards readily consumed insects, but refused to eat plants selected for their palatability to herbivorous lizards. Our data suggest that M. moreletii is carnivorous.
COURTSHIP BEHAVIOUR OF MALE THREESPINE STICKLEBACKS (GASTEROSTEUS ACULEATUS) FROM OLD AND NEW HYBRID ZONES
Authors: Hay  , McPhail
Published: July 2002

We compared courtship behaviour of male threespine sticklebacks (Gasterosteus aculeatus) from an 'old' hybrid zone (OldHZ) and 'new' hybrid zones (NewHZ) in southwest British Columbia. High frequencies of phenotypically-intermediate forms occurred in each HZ, between the low-plated freshwater (FW) and high-plated marine (MAR) forms. The OldHZ was formed early in the present post-glacial period and probably has existed for thousands of years. The 'new' HZ (NewHZ) is a system of drainage ditches built in the late nineteenth century. In the laboratory, we quantified and compared courtship behaviour (zigzags, bites, creeping through, fanning) of males from each HZ. We compared these results with those from a previous study that quantified courtship of FW and MAR males. In general, courtship of male from the NewHZ was intermediate between the FW and MAR forms, but zigzag courtship of males from the OldHZ was the significantly less vigorous. In general, other courtship behaviour (biting, fanning, gluing, crawling through and the first response) of hybrid zones males was intermediate between FW and MAR males. Within each HZ, courtship differences were not related to phenotype (lateral plates) or size of males or females. The reduced zigzag courtship of OldHZ males is consistent with the hypothesis that change in courtship behaviour of hybrid phenotypes is evidence of the development of premating isolating mechanisms between the FW and MAR forms. There is no evidence, however, of any form of hybrid inviability although we did suspect that we had less success getting OldHZ males to build nests in our laboratory tanks. Without firm evidence of some form of hybrid inviability, the conclusion that male courtship could serve as an isolating mechanism remains speculative.
FORAGING FOR NECTAR AND POLLEN ON THISTLE FLOWERS (CIRSIUM VULGARE) AND ARTIFICIAL FLOWERS: HOW BUMBLE BEES (BOMBUS IMPATIENS) RESPOND TO COLONY REQUIREMENTS
Authors: Plowright  , Cohen-Salmon Denis , Landry France , Simonds Virginia
Published: July 2002

This study documented two behavioural responses to pollen and nectar deprivation in a colony of bumble bees: flower handling and choice. In two laboratory experiments, colonies were deprived, on successive days, of pollen and of nectar. In the first experiment, the bees foraged on thistle flowers, and in the second, they foraged on artificial flowers. In both studies, flower handling depended on deprivation condition: the relative frequency of scrabbling for pollen rather than probing for nectar was of the order of tenfold higher when the colony was deprived of pollen. Choice also depended on deprivation condition. In Experiment 1, old thistle flowers, which had abundant pollen visible, were visited more frequently than new flowers when the colony was deprived of pollen. Similarly in Experiment 2, the row of artificial flowers containing both nectar and pollen was visited more frequently than the row of flowers containing only nectar when the colony was deprived of pollen.
OLIGOMERIZATION IN COPEPODA CYCLOPOIDA AS A KIND OF ORTHOGENETIC EVOLUTION IN THE ANIMAL KINGDOM
Authors: Klein J. C. Von Vaupel , Monchenko
Published: July 2002

The morphological-evolutionary notions on oligomerization (i.e., reduction in numbers of segments) of the thoracic limbs and the first antenna in Copepoda Cyclopoida are examined in detail. It is shown that the process of oligomerization is correlated to a large extent with a decrease in body length. The oligomerization of the thoracic limbs is evolutionarily irreversible, thus capable of channeling the further pathways of morphological development. Consequently, its successive steps in phylogenetic lineages are considered to represent a kind of orthogenetic evolution. Les notions morphologiques-evolutionnaires sur l'oligomerisation (c'est-a-dire sur la reduction du nombre des segments) des pattes thoraciques et de la premiere antenne chez les Copepodes Cyclopoida sont examinees en detail. Il est montre que le processus d'oligomerisation est en correlation dans une large mesure avec une diminution de la longueur du corps. L'oligomerisation des pattes thoraciques est evolutionnairement irreversible, etant ainsi capable d'orienter le cours ulterieur du developpement morphologique. Par consequent, ses pas successifs dans les lignees phylogenetiques sont consideres comme representant une sorte d'evolution orthogenetique.
Identification and host range assessment of Paratylenchus nanus (Tylenchida: Tylenchulidae) and Paratrichodorus minor (Triplonchida: Trichodoridae)
Authors: Bell Nigel , Watson Richard
Published: July 2002

Adult and juvenile characters were used to identify Paratylenchus nanus Cobb, 1923 and Paratrichodorus minor (Colbran, 1956) Siddiqi, 1974 from soils under pasture in New Zealand. In glasshouse tests of 15 pasture plants, common in New Zealand, all good hosts (ratio of final to initial population >1) of P. nanus were grasses, namely Dactylis glomerata , Lolium multiflorum and L. perenne (Neotyphodium endophyte-infected and-free), all new host records for this species. Good hosts of P.minor included those listed for P.nanus and Festuca arundinacea (endophyte-free) , Poa annua , Trifolium pratense , T. repens and T. subterraneum. Except for T. repens, these are all new host records for P.minor in New Zealand.
Basel's Rural Pastors as Mediators of Confessional and Social Discipline
Authors: Burnett Amy Nelson
Published: July 2002

Overthe last two decades historians of early modern Europe have adopted the paradigm of confessionalization to describe the religious, political, and cultural changes that occurred in the two centuries following the Reformation.1As an explanatory model confessionalization has often been portrayed as the religious and ecclesiastical parallel to the secular and political process of social discipline, as formulated by Gerhard Oestreich.2In its simplest form, the process of confessional and social discipline is depicted as hierarchical and unidirectional: the impulse to discipline and control came from the secular and ecclesiastical authorities, and the laity, particularly the peasants at the bottom of the hierarchy, had little possibility of exerting counterpressures on those seeking to shape their beliefs and behavior. The inevitable result of the disciplinary process was the gradual suppression of popular culture and the imposition of new standards of belief and behavior on the subjects of the territorial state.
Formation of grain-coating chlorite in sandstones. Laboratory synthesized vs. natural occurrences
Authors: Aagaard P. , Jahren J. S. , Harstad A. O. , Nilsen O. , Ramm M.
Published: July 2002

Grain-coating chlorites in clastic quartz-rich sandstones have long been recognized as an important porosity-preserving constituent in medium- to deep-burial diagenesis. As little is known about the occurrence and origin of chlorite coatings, chlorite synthesis experiments were performed to study how grain-coating chlorites form in certain sandstones during burial. The starting material was naturally-occuring sandstones from the Oseberg and the Veslefrikk fields offshore Norway, where the same sandstone formation is buried to different depths due to faulting. Grain-coating chlorites exist below ~3000 m burial depth only. At shallower burial (2400 m), an X-ray amorphous iron containing thin clay coating is present.

The samples were heated to 200 and 250°C (at water vapour pressure) in a hydrothermal bomb for 2–4 weeks. Both starting material and end-products were studied (electron-) optically in both scanning and transmission microscopes. The TEM showed the Fe-rich precursor material to consist of a fine-grained berthierine-dominated mixed-layer. The neoformed grain coatings in the reacted samples were similar in appearance to naturally-occurring chlorite coatings. The TEM analyses of individual grains documented an Fe-rich chloritic phase with an average composition of Mg0.41Fe3.52Mn0.10Al1.51(Al0.58Si3.42)O10(OH)8. The reacted waters were found to be close to saturation with the newly formed chlorites.

Grain-coating chlorite thus appears to form in the natural environment from Fe-rich berthierine precursors at a burial depth corresponding to a temperature around 90°C.
Volcanogenic clays in Jurassic and Cretaceous strata of England and the North Sea Basin
Authors: Jeans C. V. , Wray D. S. , Merriman R. J. , Fisher M. J.
Published: July 2002

The nature and origin of authigenic clay minerals and silicate cements in the Jurassic and Cretaceous sediments of England and the North Sea are discussed in relation to penecontemporaneous volcanism in and around the North Sea Basin. Evidence, including new REE data, suggests that the authigenic clay minerals represent the argillization of volcanic ash under varying diagenetic conditions, and that volcanic ash is a likely source for at least the early silicate cements in many sandstones. The nature and origin of smectite-rich, glauconite-rich, berthierine-rich and kaolin-rich volcanogenic clay mineral deposits are discussed. Two patterns of volcanogenic clay minerals facies are described. Pattern A is related to ash argillization in the non-marine and marine environments. Pattern B is developed by the argillization of ash concentrated in the sand and silt facies belts in the seas bordering ash-covered islands and massifs. It is associated with regression/ transgression cycles which may be related to thermal doming and associated volcanism, including the submarine release of hydrothermal fluids rich in Fe. The apparent paucity of volcanogenic clay deposits in the Jurasssic and Early Cretaceous sediments of the North Sea is discussed.
Oil migration makes the difference: regional distribution of carbonate cement δ13C in northern North Sea Tertiary sandstones
Authors: Macaulay C. I. , Fallick A. E. , Haszeldine R. S. , McAulay G. E.
Published: July 2002

Carbonate cements in Tertiary reservoir sandstones from the northern North Sea have distinctive carbon isotopic compositions (δ13C). Oil migration up faults from deeper structures and biodegradation of oil pools are factors of particular importance in influencing the δ13C of carbonate cements in these sandstones. As a result, δ13C can be used as an exploration guide to locating the positions of vertical leakoff points from the Jurassic source rocks. The histogram distribution of δ13C in these carbonate cements is trimodal, with peaks at around −26, −3 and +12‰ (ranges −22 to −30, +2 to −10 and +8 to +18‰, respectively). Bacterial processes played major roles in determining this distribution, with oxidative biodegradation of oil resulting in carbonate cements with very negative compositions and bacterial fermentation resulting in the positive δ13C cements. δ13C distribution patterns may be used to differentiate Tertiary reservoir sandstones from Jurassic in the northern North Sea, and these regional carbonate cement δ13C datasets allow geologically useful inferences to be drawn from δ13C data from new sample locations.
Palaeocene- early Eocene climatic evolution in the Tethyan realm: clay mineral evidence
Authors: Bolle M.-P. , Adatte T.
Published: July 2002

Clay mineral associations of Palaeocene and Eocene age, with special attention to the late Palaeocene thermal maximum, have been examined in ten sections from the Tethys (Egypt, Israel, Tunisia, Spain and Kazakhstan) and Atlantic (England). A widespread abundance of kaolinite in marine sediments at all locations suggests a warm and humid climate with high rainfall in the Tethys region during the early Palaeocene. In the coastal basins along the southern margin (Israel and southern Tunisia), kaolinite disappears gradually giving way to palygorskite and sepiolite, suggesting the progressive development of arid climatic conditions in this part of the Tethys from the late Palaeocene to the early Eocene. Remarkably, kaolinite increases strongly throughout most of the Tethys during the late Palaeocene thermal maximum (LPTM) reflecting an episode of humidity and warmth and coincident with a global maximum warmth of seawaters inferred from oxygen isotopic data.
Clay mineralogical variations and evolutions in sandstone sequences near a coal seam and shales in the Westphalian of the Campine Basin (NE Belgium)
Authors: Van Keer I. , Muchez Ph. , Viaene W.
Published: July 2002

Mineralogical trends have been investigated on a detailed scale in two Westphalian fluvial sandstone sequences in contact with either a coal seam or shales. The evolution in an authigenic clay mineral assemblage can be related to changes in the pH of the pore-water. Firstly, kaolinite formed early in diagenesis, mainly as a result of K-feldspar dissolution and alteration. This process, which took place under acidic conditions, consumed protons. Subsequently the pH of the pore-water increased and after compaction, illitization of kaolinite occurred under near neutral conditions. Deep burial is marked by dickite formation, which again reflects acidic conditions. Distribution of clay minerals is related to meteoric water flux through the sediments and the release of organic acids and CO2 from coalification of organic matter in the underlying strata.
Clay mineral assemblages in flysch from the Campo de Gibraltar area (Spain)
Authors: Ruiz Cruz M. D.
Published: July 2002

In order to determine the relative influence of palaeoenvironmental and diagenetic processes in clay assemblages, as well as their significance, both fine- and coarse-grained sediments from the Campo de Gibraltar flysch have been studied by means of X-ray diffraction, optical and electron microscopy, and chemical analysis. Diagenetic modifications appear to be lithologically controlled and mainly affect coarse-grained sediments, where Fe-chlorites, illite and kaolinite are the more characteristic authigenic clay minerals. The evolution of detrital assemblages, determined in fine-grained beds, indicates that, from Cretaceous to Eocene times, clay mineralogy, characterized by the opposite kaolinite+smectite and illite + I-S mixed-layer assemblages, was mainly controlled by sources, climate and transport processes. On the other hand, from the Oligocene, clay mineral assemblages, characterized either by the abundance of kaolinite, or by the illite+chlorite association, mainly reflect the petrology of source rocks, as a consequence of climatic cooling and the increasing tectonic activity, which impede the development of soils.
Intrusive calcite-carbonatite occurrence from Mt. Vulture volcano, southern Italy
Authors: Rosatelli G. , Stoppa F. , Jones A. P.
Published: July 2002

Intrusive calcite-carbonatite ejecta (sovite) in the lowermost tephra layers of the Mt. Vulture alkaline mafic-ultramafic volcano (Upper Pleistocene), is the first intrusive carbonatite sample from southern Europe. The sovite is of coarse granularity and shows some textural and mineralogical layering. It is mainly formed of calcite (up to 3.5 wt.% MgO, and 0.53 wt.% SrO), less dolomite (average 18.2 wt.% MgO, and up to 2.1 wt.% SrO), spinel (60 wt.% Al2O3, 26.5 wt.% MgO, 10.7 wt.% FeO) and olivine (Fo99). Perovskite and apatite have been found only as microlites. Intergranular vugs are scattered throughout the rocks and small composite inclusions occur in calcite.

The mineral chemistry, high temperature melt inclusions, overall isotopic compositions, and the REE distribution are consistent with a primary igneous origin. Compared with world average sovite compositions, the Vulture sovite has lower LILE and HFSE but Rb, Sr, Th and U are high. The REE abundance is typical of carbonatites, having an LREE/HREE value of ∼100. The δ13C (−4.8% SMOW) is in the range for mantle-derived carbonatites. The 143Nd/144Nd (0.512648±15) and 87Sr/86Sr (0.705978±10) ratios show close similarity between the sovite and the Vulture alkaline mafic rocks. The sovite ejecta are interpreted as a crystallization product of carbonate ultramafic liquid. In common with many shallow-level carbonatites from other localities, the recrystallization of rather pure Mg-calcite, the presence of dissolution vugs and the depletion of some HFSE and the relatively high δ18O values, suggest that a secondary process, such as hydrothermal leaching, affected the rock.
Infrared powder-absorption spectroscopy of Ca-free P21/c clinopyroxenes
Authors: Boffa Ballaran T. , Carpenter M. A. , Ross N. L.
Published: July 2002

Infrared powder-absorption spectra of ten synthetic P21/c pyroxenes with compositions in the clinoenstatite–clinoferrosilite system have been collected at room temperature in the range 50–1500 cm−1. Variations of peak positions as a function of Fe content have been obtained for those vibrational bands whose trend could be followed across the solid solution. Local elastic strains arising from cation substitution have been quantified by means of the autocorrelation function, which gives a measure (Δcorr) proportional to the line width of the IR bands. The structure of clinoenstatite appears to be very homogeneous, whereas Fe-rich pyroxenes have high degrees of local structural hetereogeneities. A positive deviation from linearity of the Δcorr values is observed in the spectral region between 100 and 250 cm−1 and may be indicative of a positive excess enthalpy of mixing of this solid solution. At higher energies the large changes in the phonon spectra as Fe content increases are associated with rotation and deformation of the tetrahedral chains for accommodating the larger cation. The results are compared with similar studies on other chain silicates.
Expression of macrophage inflammatory protein-3α, stromal cell–derived factor-1, and B-cell–attracting chemokine-1 identifies the tonsil crypt as an attractive site for B cells
Authors: Casamayor-Pallejà Montserrat , Mondière Paul , Amara Ali , Bella Chantal , Dieu-Nosjean Marie-Caroline , Caux Christophe , Defrance Thierry
Published: July 2002

The expression of 3 lymphoid chemokines—macrophage inflammatory protein-3α (MIP-3α), stromal cell–derived factor-1 (SDF-1), and B-cell–attracting chemokine-1 (BCA-1)—in the tonsil and the possible correlation between their sites of expression and B-cell localization within this tissue were studied. The results show that all 3 chemokines are produced in the crypts but differ by the nature of the cells that produce them and their location within the crypt. SDF-1 and MIP-3α are produced by epithelial cells, but their secretion is mutually exclusive. Both MIP-3α– and SDF-1–expressing cells are in close contact with memory B cells. By contrast, BCA-1–producing cells in the crypt are not epithelial and form clusters colocalized with plasma cells. Altogether, these data suggest that the chemokines produced in the tonsillar crypt may (1) attract memory B cells to antigen and (2) recruit and retain plasma cells and memory B cells within the supportive epithelial microenvironment of the crypt.
Illegitimate switch recombinations are present in approximately half of primary myeloma tumors, but do not relate to known prognostic indicators or survival
Authors: Ho P. Joy , Brown Ross D. , Pelka Gregory J. , Basten Antony , Gibson John , Joshua Douglas E.
Published: July 2002

The myeloma plasma cell is a postgerminal center, isotype-switched B cell. Chromosomal translocations into immunoglobulin heavy chain (IgH) switch regions, recombination sites in isotype switching, were initially demonstrated in myeloma cell lines but only a limited number of primary tumors. Molecular cytogenetics have since been applied to a series of primary tumors, in which IgH translocations accounted for many recurrent aberrations, among numerous nonrecurrent changes of unknown significance. This study, therefore, examined primary myeloma for IgH switch translocations using an established Southern blot assay that detected illegitimate switch recombinations. Sensitivity of the method was established by confining the analysis to 21 samples (4 stable, 17 progressive disease) with demonstrable legitimate isotype switches, of a total of 60 samples. Illegitimate recombinations were found in 12 or 57% (1 stable, 11 progressive) of 21 samples, comparable with estimates by molecular cytogenetics. The presence of switch translocations was supported by demonstrating up-regulated expression in myeloma marrow of cyclin D1 and fibroblast growth factor receptor 3 (FGFR3), candidate oncogenes on chromosomes 11q13 and 4p16, respectively. Illegitimate switches were detected most frequently in Sμ, with more than one region involved in 6 cases. Although these results confirmed the presence of switch translocations in primary myeloma, their absence in 43% of cases may imply heterogeneity of pathogenesis. In progressive disease, there was no significant difference between patients with and without illegitimate switches in survival, nor the prognostic indicators of β2microglobulin (β2m) and serum thymidine kinase (STK). Hence IgH switch translocations as a single entity are unlikely to be a feature of disease progression or have prognostic significance.
Myeloblastin is an Myb target gene: mechanisms of regulation in myeloid leukemia cells growth-arrested by retinoic acid
Authors: Lutz Pierre G. , Houzel-Charavel Anne , Moog-Lutz Christel , Cayre Yvon E.
Published: July 2002

A pivotal role has been assigned to Myb in the control of myeloid cell growth. Although Myb is a target of retinoic acid, little is known about the mechanisms by which it may contribute to induced growth arrest in leukemia cells. Indeed, few Myb target genes are known to be linked to proliferation. Myeloblastin is involved in the control of proliferation in myeloid leukemia cells. It is expressed early during hematopoiesis and is a granulocyte colony-stimulating factor–responsive gene. Myeloblastin can confer factor-independent growth to hematopoietic cells, an early step in leukemia transformation. The myeloblastin promoter contains PU.1, C/EBP, and Myb binding sites, each of which are critical for constitutive expression in myeloid cells. Inhibition of myeloblastin expression in leukemia cells growth-arrested by retinoic acid is demonstrated to depend on Myb down-regulation. Myb is shown to induce myeloblastin expression and abolish its down-regulation by retinoic acid. Altogether, the data offer a clue as to how a myeloid-specific transcriptional machinery can be accessible to regulation by retinoic acid and point to myeloblastin as a novel target of Myb. This link between Myb and myeloblastin suggests a previously nonidentified Myb pathway through which growth arrest is induced by retinoic acid in myeloid leukemia cells.
Erythropoietin-dependent transformation of myelodysplastic syndrome to acute monoblastic leukemia
Authors: Bunworasate Udomsak , Arnouk Hilal , Minderman Hans , O'Loughlin Kieran L. , Sait Sheila N. J. , Barcos Maurice , Stewart Carleton C. , Baer Maria R.
Published: July 2002

Acute monoblastic leukemia (acute myeloid leukemia [AML], French-American-British type M5a) with leukemia cutis developed in a patient 6 weeks after the initiation of erythropoietin (EPO) therapy for refractory anemia with ringed sideroblasts. AML disappeared from both marrow and skin after the discontinuation of EPO. Multiparameter flow cytometric analysis of bone marrow cells demonstrated coexpression of the EPO receptor with CD45 and CD13 on the surface of blasts. The incubation of marrow cells with EPO, compared to without, resulted in 1.3- and 1.6-fold increases, respectively, in tritiated thymidine incorporation and bromodeoxyuridine incorporation into CD13+ cells. Clinical and laboratory findings were consistent with the EPO-dependent transformation of myelodysplastic syndrome (MDS) to AML. It is concluded that leukemic transformation in patients with MDS treated with EPO may be EPO-dependent and that management should consist of the discontinuation of EPO followed by observation, if clinically feasible.
Receptor specificity in the self-renewal and differentiation of primary multipotential hemopoietic cells
Authors: Zeng Hui , Masuko Masayoshi , Jin Liqing , Neff Tobias , Otto Kevin G. , Blau C. Anthony
Published: July 2002

To determine whether cytokine-induced signals generate unique responses in multipotential hemopoietic progenitor cells, the signaling domains of 3 different growth factor receptors (Mpl, granulocyte–colony-stimulating factor [G-CSF] receptor, and Flt-3) were inserted into mouse primary bone marrow cells. To circumvent the activation of endogenous receptors, each signaling domain was incorporated into an FK506 binding protein (FKBP) fusion to allow for its specific activation using synthetic FKBP ligands. Each signaling domain supported the growth of Ba/F3 cells; however, only Mpl supported the sustained growth of transduced marrow cells, with a dramatic expansion of multipotential progenitors and megakaryocytes. These findings demonstrate that the self-renewal and differentiation of multipotential progenitor cells can be influenced through distinct, receptor-initiated signaling pathways.
Functional analysis of the C-terminal flanking sequence of platelet glycoprotein Ibα using canine–human chimeras
Authors: Shen Yang , Dong Jing-fei , Romo Gabriel M. , Arceneaux Wendy , Aprico Andrea , Gardiner Elizabeth E. , López José A. , Berndt Michael C. , Andrews Robert K.
Published: July 2002

Platelet glycoprotein Ib-IX-V (GPIb-IX-V) mediates adhesion to von Willebrand factor (vWF) in (patho)physiological thrombus formation. vWF binds the N-terminal 282 residues of GPIbα, consisting of an N-terminal flank (His1–Ile35), 7 leucine-rich repeats (Leu36–Ala200), a C-terminal flank (Phe201–Gly268), and a sulfated tyrosine sequence (Asp269–Glu282). By expressing canine–human chimeras of GPIbα on Chinese hamster ovary cells, binding sites for functional anti-GPIbα antibodies to individual domains were previously mapped, and it was shown that leucine-rich repeats 2 to 4 were required for optimal vWF recognition under static or flow conditions. Using novel canine–human chimeras dissecting the C-terminal flank, it is now demonstrated that (1) Phe201-Glu225 contains the epitope for AP1, an anti-GPIbα monoclonal antibody that inhibits both ristocetin- and botrocetin-dependent vWF binding; (2) VM16d, an antibody that preferentially inhibits botrocetin-dependent vWF binding, recognizes the sequence Val226-Gly268, surrounding Cys248, which forms a disulfide-bond with Cys209; (3) vWF binding to chimeric GPIbα is comparable to wild-type in 2 chimeras in which the sixth leucine-rich repeat was of the same species as the first disulfide loop (Phe201-Cys248) of the C-terminal flank, suggesting an interaction between these domains may be important for optimal vWF binding; and (4) replacing the C-terminal flank second disulfide loop (Asp249-Gly268) in human GPIbα with the corresponding canine sequence enhanced vWF binding under static and flow conditions, providing the first evidence for a gain-of-function phenotype associated with the second loop of the C-terminal flank.
Elastic tissue abnormalities resembling pseudoxanthoma elasticum in β thalassemia and the sickling syndromes
Authors: Aessopos Athanasios , Farmakis Dimitrios , Loukopoulos Dimitris
Published: July 2002

The development of clinical and histopathologic manifestations of a diffuse elastic tissue defect, resembling inherited pseudoxanthoma elasticum (PXE), has been encountered with a notable frequency in patients with β thalassemia, sickle cell disease, and sickle thalassemia. The PXE-like clinical syndrome, consisting of skin, ocular, and vascular manifestations, has a variable severity in these hemoglobinopathies and it is age-dependent, with a generally late onset, after the second decade of life. The defect is believed to be acquired rather than inherited and related to the consequences of the primary disease. The high prevalence of the findings implicates the elastic tissue injury as one of the main comorbid abnormalities encountered in β thalassemia and the sickling syndromes. In these patients a number of complications, sometimes serious, has been recognized to be related to ocular and vascular elastic tissue defects. Because several organ systems are involved, each medical specialty should be aware of the phenomenon. This coexistence, on the other hand, introduces a novel pathogenetic aspect of PXE and an important research challenge.
Reduced lymphomyeloid repopulating activity from adult bone marrow and fetal liver of mice lacking expression of STAT5
Authors: Bunting Kevin D. , Bradley Heath L. , Hawley Teresa S. , Moriggl Richard , Sorrentino Brian P. , Ihle James N.
Published: July 2002

Signal transducers and activators of transcription (STATs) are intracellular mediators of cytokine receptor signals. Because many early-acting growth factors have been implicated in STAT5 activation, this study sought to investigate whether STAT5 may be a transcriptional regulator of hematopoietic stem cell (HSC) long-term repopulating activity. To test this possibility, bone marrow (BM) and fetal liver (FL) cells from mice containing homozygous deletions of both STAT5a and STAT5b genes (STAT5ab−/−) were characterized for hematopoietic repopulating activities. BM and FL grafts were capable of repopulating lymphoid and myeloid lineages of lethally irradiated primary and secondary hosts, with defects observed primarily in T-lymphocyte engraftment. Because only a fraction of normal HSC function is required to reconstitute hematopoiesis, competitive repopulation assays of adult BM or FL cells were used against wild type adult BM or FL cells to quantitate stem cell function. In these analyses, average 25-, 28-, 45-, and 68-fold decreases in normal repopulating activity were evident in granulocyte (Gr-1+), macrophage (Mac-1+), erythroid progenitor (Ter119+), and B-lymphocyte (B220+) populations, respectively, with T lymphocytes (CD4+) always undetectable from the STAT5ab−/− graft. Consistent with previous reports of divergence between stem cell phenotype and function in cases of perturbed hematopoiesis, the absolute number of cells within Sca-1+c-kit+lin− or lin− Hoechst 33342 side population fractions was not significantly different between wild type and STAT5ab−/−BM or FL cells. These results demonstrate that a significant proportion of the growth factor signals required for multilineage reconstitution potential of HSCs is STAT5 dependent.
Enforced expression of the Ikaros isoform IK5 decreases the numbers of extrathymic intraepithelial lymphocytes and natural killer 1.1+ T cells
Authors: Tucker Sean N. , Jessup Heidi K. , Fujii Hodaka , Wilson Christopher B.
Published: July 2002

The zinc-finger protein Ikaros plays an important role in lymphoid homeostasis, and loss of Ikaros expression through germline disruption impairs lymphoid development. However, the role played by Ikaros after commitment to the T-cell lineage is unclear. To address this question, this study used the lck proximal promoter to drive the expression in T-cell progenitors of a naturally occurring short Ikaros isoform (IK5), which lacks the DNA-binding domain, reasoning that IK5 will form heterodimers with long isoforms and perturb their function. The IK5 transgene led to a selective and dramatic decrease in extrathymic intestinal intraepithelial lymphocytes (IELs) and natural killer 1.1+ T (NK T) cells with little effect on conventional αβ T cells, which resembles the T-cell phenotype of interleukin-15 receptor α chain (IL-15Rα) and IL-2/IL-15 receptor β chain (IL-2Rβ) knockout mice. The expression of IL-2Rβ on double-negative T-cell progenitors of bi-5 was reduced, but enforced expression of IL-2Rβ did not rescue IELs or NK T cells in bi-5 transgenic mice, suggesting that Ikaros or Ikaros family members regulate the expression of additional genes that are essential for the development of IELs and NK T cells. The study concludes that modest changes in the ratio of short to long Ikaros isoforms can substantially perturb T-cell development, and the development of IELs and NK T cells is particularly sensitive to such changes.
Arginine supplementation of sickle transgenic mice reduces red cell density and Gardos channel activity
Authors: Romero José R. , Suzuka Sandra M. , Nagel Ronald L. , Fabry Mary E.
Published: July 2002

Nitric oxide (NO), essential for maintaining vascular tone, is produced from arginine by nitric oxide synthase. Plasma arginine levels are low in sickle cell anemia, and it is reported here that low plasma arginine is also found in our sickle transgenic mouse model that expresses human α, human βS, and human βS-Antilles and is homozygous for the mouse βmajor deletion (S+S-Antilles). S+S-Antilles mice were supplemented with a 4-fold increase in arginine that was maintained for several months. Mean corpuscular hemoglobin concentration (MCHC) decreased and the percent high-density red cells was reduced. Deoxy K+ efflux is characteristic of red cells in sickle cell disease and contributes to the disease process by increasing the MCHC and rendering the cells more susceptible to polymer formation. This flux versus the room air flux was reduced in S+S-Antilles red cells from an average value of 1.6 ± 0.3 mmol per liter of red cells × minute (FU) in nonsupplemented mice to 0.9 ± 0.3 FU (n = 4, P < .02, paired t test) in supplemented mice. In room air, Vmax of the Ca++-activated K+ channel (Gardos) was reduced from 4.1 ± 0.6 FU (off diet) to 2.6 ± 0.4 FU (n = 7 and 8,P < .04, t test) in arginine-supplemented mice versus clotrimazole. In conclusion, the major mechanism by which arginine supplementation reduces red cell density (MCHC) in S+S-Antilles mice is by inhibiting the Ca++-activated K+ channel.