bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigations toward Using VRML for Distributed Medical Collaboration
Authors: Markush J. Peter C. , Grimes Gary J. , Merril Jonathan R.
Published: July 2002

This report describes preliminary research and experiments towards the collaborative viewing and manipulation of three-dimensional computer models of human anatomy and physiology on low-end computers using limited bandwidth. A proposed system is described using a set of recommended requirements. Experiments that were conducted to explore the feasibility of some aspects of the proposed system are also described. The resulting experimental system was implemented on networked 100 MHz and 90 MHz Pentium-based computers enhanced with 3-D graphics accelerators. Geometry for the anatomy models were stored in Virtual Reality Modeling Language (VRML) version 1.0 files, which could be accessed remotely over the Internet. Some models were later implemented as VRML 2.0 files, which enabled the storage of simple physiological behaviors with the geometry. The use of VRML, the de facto standard file format for 3-D modeling on the Web, in a medical collaboration system would help make such systems, which have been typically implemented on special-purpose hardware with proprietary anatomical and physiological models, much more accessible.
Maintaining Spatial Orientation during Travel in an Immersive Virtual Environment
Authors: Bowman Doug A. , Davis Elizabeth T. , Hodges Larry F. , Badre Albert N.
Published: July 2002

An experiment is presented comparing the effects of various virtual travel techniques in an immersive virtual environment (VE) on the spatial orientation of users. The experiment was designed and implemented in the context of a formal framework for the design and evaluation of VE travel techniques. Subjects traveled through virtual corridors, noting the location of objects along the way, and were asked to point in the direction of one of these objects when the end of the corridor was reached. Results indicate that virtual travel techniques, in which users do not physically translate their bodies, can allow the maintenance of a user's spatial orientation as measured by a pointing task. The experiment also replicates an earlier result, showing that path dimension significantly affects user performance. Finally, the strategies used by subjects to perform the task were shown to be significant, indicating that performance depends not only on the technique, environment, and task, but also on the sophistication of the user.
Factors Affecting the Perception of Interobject Distances in Virtual Environments
Authors: Waller David
Published: July 2002

Two experiments collectively explored four factors that may influence people's judgments of exocentric (interobject) distances in virtual environments. Participants freely navigated in a simple virtual environment and repeatedly made magnitude estimations of exocentric distances. Distances were generally overestimated. An exponential model (Stevens' power law) fit the data, and exponent estimates were generally less than unity. Geometric field of view (GFOV) and the presence of error-corrective feedback were found to have the strongest effect on accuracy. In fact, distance perception was nearly veridical when made with an 80 deg. GFOV and when receiving feedback. Display type (head-mounted versus desktop) and the presence of additional perspective cues were less influential.
A Developmental Model for the Evolution of Artificial Neural Networks
Authors: Astor J. C. , Adami C.
Published: July 2002

We present a model of decentralized growth and development for artificial neural networks (ANNs), inspired by developmental biology and the physiology of nervous systems. In this model, each individual artificial neuron is an autonomous unit whose behavior is determined only by the genetic information it harbors and local concentrations of substrates. The chemicals and substrates, in turn, are modeled by a simple artificial chemistry. While the system is designed to allow for the evolution of complex networks, we demonstrate the power of the artificial chemistry by analyzing engineered (handwritten) genomes that lead to the growth of simple networks with behaviors known from physiology. To evolve more complex structures, a Java-based, platform-independent, asynchronous, distributed genetic algorithm (GA) has been implemented that allows users to participate in evolutionary experiments via the World Wide Web.
Beyond Grain and Grandeur: An Answer to Critics and an Agenda for Future Research
Authors: Moravcsik Andrew
Published: July 2002

Moravcsik's reply to the six commentaries deals with sources omitted from the original article, the use of evidence in his analysis of the Fouchet Plan and the “empty chair” crisis, and broader critiques of (and proposed alternatives to) the commercial interpretation of French policy on European integration during the presidency of Charles de Gaulle. Moravcsik concedes some of the points raised by the critics and offers a more qualified and nuanced restatement of his argument, but he sticks to his basic contention that “commercial interests were a dominant and sufficient motivation for French policy in Europe.”
NGO Influence in International Environmental Negotiations: A Framework for Analysis
Authors: Betsill Michele M. , Corell Elisabeth
Published: July 2002

Current literature on global environmental politics largely considers NGO influence implicit and unproblematic. Responding to several weaknesses in the literature, we propose a coherent research framework for assessing NGO influence in international environmental negotiations. We contend that influence can be said to have occurred when NGOs intentionally transmit information that alters the behavior of negotiators, and call for collecting and analyzing evidence of NGO influence in a more systematic fashion. Our framework, which relies on the use of multiple data types, sources, and methods, controls for over-determination and allows researchers to identify, with a sound degree of confidence, instances of NGO influence in international environmental negotiations. The resulting comparability provides a basis for analysis of NGO influence across cases, and ultimately contributes to better understanding of the variation of NGO influence in global environmental politics.
HOW INTEREST RATES WERE SET, 2500 BC-1000 AD: Máš, tokos and foenus as Metaphors for Interest Accruals
Authors: Hudson Michael
Published: July 2002

The earliest interest rates in Mesopotamia, Greece and Rome were set not "economically" to reflect profit or productivity rates, but by the dictates of mathematical simplicity of calculation. The interest that was "born" calendrically did not take the form of young animals, but rather of the "unit fraction," the smallest unit fraction in each of the above fractional systems: 1/60th in the Mesopotamia, 1/10th in Greece, and 1/12th in Rome. The "birth" or "calf/kid" metaphor for interest thus referred to "baby fractions", not literally baby animals.
Electronically Available Surveys of Attitudes Toward Animals
Authors: Herzog Harold , Dorr Lorna
Published: July 2002

Much of the research on attitudes toward non-human species has been conducted with non-representative samples. Largely ignored in the literature on human/animal interactions are surveys conducted by commercial polling organizations using large probability samples of Americans. Many of these surveys contain information relevant to attitudes about animals and animal welfare issues. This information is available to researchers electronically at little or no cost through organizations such as the Roper Center for Public Opinion Research and the National Opinion Research Center.
Horse Maiming in the English Countryside: Moral Panic, Human Deviance, and the Social Construction of Victimhood
Authors: Yates Roger , Powell Chris , Beirne Piers
Published: July 2002

The societal reaction to a series of horse assaults in rural Hampshire during the 1990s was a rare example of a moral panic about crime and deviance in which animals other than humans occupy, or seemed to occupy, the central role of victim. This paper explores how the nature of the relationships between humans and animals is revealed through authoritative utterances about offenders and victims by the mass media, the police, and the humans who felt they had a stake in the horses' well-being. Analysis of how and when victimhood is ascribed to animals helps to uncover the invisible assaults routinely inflicted on them - in the name of business or pleasure, for example - and against whose human perpetrators the categories of criminalization are almost never applied.
THE MACROEVOLUTIONARY DIVERSIFICATION OF FEMALE AND MALE COMPONENTS OF THE STICKLEBACK BREEDING SYSTEM
Authors: McLennan Deborah
Published: July 2002

Macroevolutionary analysis of three components in the stickleback breeding system, male/female nuptial colouration, male/female courtship and male lead/female follow to the nest revealed that: (i) a change in the male lead is always coupled with a change in the female follow, although there is no correlation between changes in particular components of the leadfollow system; (ii) a change in male courtship is coupled with a change in female courtship in all taxa but Gasterosteus and Hypoptychus. Once again, there is no correlation between changes in particular courtship components except for a possible coupling of 'male pummel' and 'female sink to the substrate'; and (iii) there is no correlation between the diversification of the male and female nuptial colour signals. These different patterns of macroevolutionary co-origination and co-diversification interact to produce unique and reliable species and sex-specific signals at the beginning of courtship + tightly coupled signals involved in coordination between spawning partners at the final stages of courtship. In order to explain the preceding macroevolutionary patterns, we now need to delineate the genetic basis for the traits in each behavioural system.
ENDOGENOUS BREEDING CYCLES IN MALE THREESPINE STICKLEBACKS, GASTEROSTEUS ACULEATUS
Authors: Bornestaf Cecilia , Borg Bertil
Published: July 2002

To study how different, constant photoperiods affect endogenous breeding cycles in the threespine stickleback, adult males were kept in separate aquaria for up to two years under light:dark (LD) 12:12 hr or LD 16:8 or for eleven months under continuous light. Nests built were destroyed weekly and fish were considered breeding as long as they kept rebuilding. Under continuous light most males nested for a much longer first period than under the other photoperiods. Most fish under both LD 12:12 and LD 16:8 exhibited breeding cycles shorter than one year. After the first or second breeding cycle, many fish, especially under LD 12:12, exhibited irregular breeding patterns. There were no significant differences in cycle length or proportion of time spent in breeding condition between these two photoperiods. The lack of these differences and the surprising observation that some fish under LD 12:12 remained in breeding condition for a very long period, suggest that a circannual cycle in photosensitivity is not the whole explanation for the endogenous control of breeding in sticklebacks.
REVIEW: THE CENTRAL ROLE OF UNCERTAINTY REDUCTION IN DETERMINING BEHAVIOUR
Authors: Inglis Ian
Published: July 2002

In complex and stochastic environments the ability to cope with the unexpected is essential for survival. This paper describes a motivational framework founded on the need to reduce uncertainty. It is centred around a merging of classifier systems, taken from the field of artificial intelligence, with the information-primacy approach to animal motivation. It is proposed that in order to deal with uncertainty the animal constructs cognitive models of its environment that are composed of hierarchies of condition-action rules. There is parallel activation of several rules at any given time, and these rules compete to determine behaviour. The rules found to be the best predictors (and may in addition have resulted in reinforcement) gain strength, whilst the less successful rules lose strength over time. Unexpected events trigger the generation of families of new rules which are then subject to environmental selection. The efficient operation of the cognitive model requires the continual reduction of uncertainty, so that information-gathering behaviour forms a substratum upon which other, more obviously goal directed, behaviours occur. High need states can break into this ongoing behaviour and give it a special direction. The framework is related to the inherent variability of behaviour, the failure of certain reinforcement contingencies to control behaviour, and approach/avoidance behaviour towards novel stimuli.
MALE CHARACTERISTICS AND FERTILISATION SUCCESS IN BLUETHROATS
Authors: Johnsen Arild , Lifjeld Jan , Andersson Staffan , Örnborg Jonas , Amundsen Trond
Published: July 2002

Extra-pair copulations (EPCs) can create or intensify sexual selection and, provided that fertilisation success is related to phenotypic traits, help explain sexual dimorphism in socially monogamous species. Previous experimental manipulations of the ornamental coloration in male bluethroats, Luscinia s. svecica, have shown effects on their social mating success, mate-guarding behaviour, and within-pair- and extra-pair paternity. This study investigates the relationship between male characteristics (reflectance of the blue throat feathers, width of the chestnut breast band, wing length, body condition and age) and fertilisation success under natural, non-experimental conditions. Combining three breeding seasons, 29% of 720 offspring were sired by extra-pair males and 54% of 136 nests contained one or more extra-pair offspring. The chroma (spectral purity) of the blue throat feathers and the width of the chestnut band were positively related to paternity in own nest, and for blue chroma this translated into a significantly positive relation with total fertilisation success. This suggests that differential within-pair paternity success exerts directional selection on the colour signal. None of the throat colour measures or morphological traits were significantly related to overall extra-pair fertilisation (EPF) success. However, restricting the analysis to males with one or more EPFs, there was a positive relation between amount of extra-pair paternity and blue chroma. Old males were more successful than young ones in achieving EPFs. Pairwise comparisons showed no plumage differences between cuckolded males and the males that cuckolded them. The absence of phenotypic correlates of male EPC-success agrees with our recent finding that females improve offspring quality through individual choice of EPC partners with 'compatible genes' rather than 'good genes' in an absolute sense. Our results indicate that experiments where traits are manipulated outside the natural range should be interpreted with caution, and illustrate the importance of a dual approach (experimental and correlative) in studies of sexual selection in the wild.
VOCAL DEVELOPMENT IN SQUIRREL MONKEYS
Authors: Hammerschmidt Kurt , Freudenstein Tamara , Jürgens Uwe
Published: July 2002

Six squirrel monkeys (Saimiri sciureus) were studied for their vocal development over the first 20 months of life, using a multi-parametric acoustic analysis. Four of the animals were normally raised, one animal ('Kaspar Hauser') was deprived of adult species-specific calls, one animal was congenitally deaf. The study showed that in all 12 call types under investigation, age-related changes in one or the other acoustic parameter occurred. The degree to which vocal structures changed, was call type-specific, with some calls showing dramatic changes and others showing only minor changes. Most changes occurred within the first four months; some lasted up to 10 months. All call types showed a high variability throughout the 20 months study period. Only five of the 12 call types showed a reduction in variability over time. Both acoustically deprived animals remained within the variability range of the normally raised animals, suggesting that the ontogenetic changes found were mainly maturational.
NON-CLADOCERAN BRANCHIOPOD CRUSTACEANS FROM SOUTHWEST PORTUGAL. I. OCCURRENCE NOTES
Authors: Fonseca Luis Cancela Da , MaChado Margarida , Cristo Margarida
Published: July 2002

The presence of non-cladoceran branchiopods was detected in only 16 out of 83 temporary freshwater ponds of SW Portugal, which were recently sampled by the authors and other researchers. Two anostracans, Branchipus cortesi and Chirocephalus diaphanus; two spinicaudatans, Cyzicus grubei and Maghrebestheria maroccana; and one notostracan, Triops cancriformis mauritanicus, were identified. All taxa are new records locally, and all but C. grubei and T. c. mauritanicus are reported for the first time from Portugal. La presence de Branchiopodes non Cladoceres a ete detectee dans 16 seulement des 83 mares temporaires d'eau douce du SO du Portugal, qui ont ete recemment echantillonnees par les auteurs et d'autres chercheurs. Deux Anostraces, Branchipus cortesi et Chirocephalus diaphanus, deux Spinicaudata, Cyzicus grubei et Maghrebestheria maroccana, et un Notostrace, Triops cancriformis mauritanicus, ont ete identifies. Tous les taxa sont nouveaux pour la faune locale et tous, sauf C. grubei et T. c. mauritanicus, sont signales pour la premiere fois du Portugal.
Membrane fusion as a morphogenetic force in nematode development
Authors: Podbilewicz Benjamin
Published: July 2002

In Caenorhabditis elegans almost all the epithelial cells fuse to form permanent syncytia. Cells in the vulva and hypodermis fuse autonomously to produce ring shaped cells with defined structures and functions. Analysis of temporal and spatial sequence of events together with ultrastructural characterisation of cell fusion intermediates show that fusion pores in specific domains of the membranes dilate and subsequently vesicles are formed. The fusomorphogenetic hypothesis states that these vesicles are targeted to different domains of the plasma membrane where they fuse, thereby causing changes in cell shape. It is proposed that cell fusion and polarised membrane recycling are involved in the formation of ring cells. Fusomorphogenesis is a working model to investigate the forces that drive pattern formation and generate diversity of developmental mechanisms in nematodes. Chez Caenorhabditis elegans, presque toutes les cellules épithéliales fusionnent pour former des syncytia permanents. Les cellules de la vulve et de l’hypoderme fusionnent de façon autonome et produisent des cellules en forme d’anneau avec des structures et des fonctions définies. L’analyse de la séquence temporelle et spatiale des événements, alliée à la caractérisation ultrastructurale des intermédiaires de fusion cellulaire, montre que des pores de fusion se dilatent dans des domaines membranaires spécifiques et que des vésicules sont par la suite formées. L’hypothèse fusomorphogénétique suggère que ces vésicules sont ciblées vers des domaines différents de la membrane plasmique, ou elles fusionnent, provoquant ainsi des changements de forme cellulaire. Il est proposé que la fusion cellulaire et le recyclage polarisé de membranes soient considérés comme impliqués dans la formation des cellules en anneau. La fusomorphogénèse est un guide de travail pour étudier les forces qui entraînent la formation d’un modèle spatial et engendrent la diversité des mécanismes de développement chez les nématodes.
Geochemical modelling of diagenetic reactions in a sub-arkosic sandstone
Authors: Barclay S. A. , Worden R. H.
Published: July 2002

A reaction path model was constructed in a bid to simulate diagenesis in the Magnus Sandstone, an Upper Jurassic turbidite reservoir in the Northern North Sea, UKCS. The model, involving a flux of source rock-derived CO2 into an arkosic sandstone, successfully reproduced simultaneous dissolution of detrital K-feldspar and growth of authigenic quartz, ankerite and illite. Generation of CO2 occurred before and during the main phase of oil generation linking source rock maturation with patterns of diagenesis in arkosic sandstones and limiting this type of diagenesis to the earlier stages of oil charging. Independent corroborative evidence for the model is provided by formation water geochemical data, carbon isotope data from ankerite and produced gas phase CO2 and the presence of petroleum inclusions within the mineral cements. The model involves a closed system with respect to relatively insoluble species such as SiO2 and Al2O3 but is an open system with respect to CO2. There are up to seven possible rate-controlling steps including: influx of CO2, dissolution of K-feldspar, precipitation of quartz, ankerite and illite, diffusive transport of SiO2 and Al2O3 from the site of dissolution to the site of precipitation and possibly the rate of influx of Mg2+ and Ca2+. Given the large number of possible controls, and contrary to modern popular belief, the rate of quartz precipitation is thus not always rate limiting.
Reply to discussion of “Extracting K-Ar ages from shales: a theoretical test”
Authors: Środoń J .
Published: July 2002

As plots of K-Ar ages vs. percentage of the detrital component of mineral mixtures containing a detrital and a diagenetic illite (or illite-smectite) have different curved shapes, the linear extrapolation method of extracting the end-member ages is not justified. The curvature depends on the difference in K2O contents; thus it can be minimized if the percentage of detrital illite is normalized to the sum of detrital illite plus illitic fraction of diagenetic illite-smectite.
An 57Fe Mössbauer spectral study of vermiculitization in the Palabora Complex, Republic of South Africa
Authors: Badreddine R. , Grandjean F. , Vandormael D. , Fransolet A. -M. , Long G. J.
Published: July 2002

Two phlogopite, two mixed-layer phlogopite-vermiculite, and two vermiculite samples collected from the Palabora Complex of South Africa have been investigated at 295 K by X-ray diffraction, chemical analysis, and Mössbauer spectroscopy. In addition the temperature dependence of the Mössbauer spectra has been measured between 95 and 295 K for one phlogopite and one mixed-layer sample. The results of the chemical analyses and the Mössbauer spectra improve our knowledge of the vermiculitization process in the Palabora Complex. Both techniques indicate oxidation of the Fe ions during the sequence: phlogopite → mixed-layer → vermiculite. Further, the Mössbauer spectra indicate that Fe oxidation occurs mainly in the octahedral sites and suggest that migration and oxidation of the Fe2+ ions from the octahedral sites to the tetrahedral sites may occur during the transformation of phlogopite into a mixed-layer phase. Finally, the vermiculitization process involves both Fe oxidation and loss of K with a concomitant increase in the Mg content.
Smectite transformation in high molar KOH solutions
Authors: Bauer A. , Velde B.
Published: July 2002

Batch reactor experiments were performed at 35°C and 80°C to determine the effect of high molar KOH solutions on the mineralogy and solution chemistry of two different smectites. The Ceca smectite is a nearly pure montmorillonite, and the Ibeco clay has a significant component of 35% beidellitic charge. Each reactor was charged with 1 g of <2 mm fraction smectite and 80, 160, 240 ml of 0.1–4 M KOH solution. In these experiments, the changes in solution composition and mineralogy were monitored as a function of time.

In the experiments, at all temperatures and under all chemical conditions, the smectite appears to change in diffracting domain size, which decreases with time. This probably reflects a change in crystal shape. The structures then become more illite rich and the diffracting domain continues to decrease.
Trace element partitioning between wollastonite and silicate-carbonate melt
Authors: Law K. M. , Blundy J. D. , Wood B. J. , Ragnarsdottir K. V.
Published: July 2002

We have performed an experimental study of the influence of varying size and charge on cation partitioning between wollastonite and silicate-carbonate melt in the system CaCO3-SiO2. The experimental conditions (3 GPa, 1420°C) lie close to the wollastonite II tc/I tc phase boundary. Results for 1+, 2+, 3+ and 4+ partitioning show parabolic dependence of partition coefficients on ionic radius, which can be fitted to the elastic strain model of Blundy and Wood (1994), wherein partitioning is described using three parameters: site radius (r0), site elasticity (apparent Young's Modulus) and the ‘strain-free’ partition coefficient (D0) for an element with radiusr0. The apparent Young's Modulus of the Ca site in wollastonite, obtained from modelling the 2+ partitioning data, is 99±3 GPa, similar to the bulk-crystal value for the polymorph wollastonite I tc.r0decreases with increasing charge on the substituent cation, whileD0also shows an approximately parabolic dependence on charge, with a maximum for 2+ cations. Partition coefficients for divalent cations Zn, Co, Fe, Cd, Mn and Pb are lower than would be predicted from their ionic radii alone, indicating a preference for the melt. This may be a consequence either of cation-carbonate complexation in the melt, or of the more distorted nature of cation co-ordination environments in melts.
Mineralogical controls on phosphorus recovery from wastewaters
Authors: Valsami-Jones E.
Published: July 2002

The removal of phosphorus from wastewaters is becoming very common, to meet water quality targets, and avoid environmental problems related to eutrophication. At the same time, agricultural application of P-rich sewage biosolids is diminishing for reasons of logistics and of public pressure. As a result P from wastewaters is ultimately disposed of in landfills. Over the long term, phosphate ore reserves will become depleted. Recycling of P from wastewaters may thus be a realistic prospect if scientific and technical issues can be resolved. At the centre of the scientific problems lie considerations about optimizing phosphate precipitation as Ca phosphates. A number of Ca phosphate minerals exist, although by far the most common of these is hydroxylapatite. Precipitation kinetic considerations, however, suggest that other Ca phosphates (such as brushite, octacalcium phosphate, whitlockite, monetite or amorphous Ca phosphate) may initially precipitate, and later recrystallize into the most stable hydroxylapatite. This article reviews the complex precipitation mineralogy, chemistry and kinetics of Ca phosphates.
Structural discontinuities in plagioclase and constraints on mixing properties of the low series: a computational study
Authors: Vinograd V. L. , Putnis A. , Kroll H.
Published: July 2002

Subsolidus phase relations in the plagioclase system are investigated using an Ising-type model. The model treats ordering of Al,Si and Na,Ca cations in three dimensions using a version of the cluster variation method. The interactions within the T (Al,Si) and M (Na,Ca) sublattices and the interactions between the T and M sublattices are constrained by the available experimental information on orderdisorder transitions in the system. The paper suggests a thermodynamic explanation for the existence of two distinct structural series (high and low) and gives constraints on the thermodynamics of low plagioclases.
A detailed structural characterization of quartz on heating through the α–β phase transition
Authors: Tucker M. G. , Keen D. A. , Dove M. T.
Published: July 2002

Total neutron scattering measurements, analysed using a modification of the reverse Monte Carlo modelling method to account for long-range crystallographic order, have been used to describe the temperature-dependent behaviour of the structure of quartz. Two key observations are reported. First, the symmetry change associated with the displacive α–β phase transition is observed in both the long-range and short-range structural correlations. Secondly, some aspects of the structure, such as the Si–O bond length and the thermally-induced dynamic disorder, the latter of which sets in significantly below the transition, are relatively insensitive to the phase transition. These results are used to show that the α-domain model of the β-phase disorder is inappropriate and that the classical soft-mode picture of the phase transition is too simplistic. Instead, it is argued that the structural behaviour is best described in terms of its ability to respond to low-frequency, high-amplitude vibrational modes. This view is supported by additional single-crystal diffuse neutron scattering measurements.
Verbeekite, monoclinic PdSe2, a new mineral from the Musonoi Cu-Co-Mn-U mine, near Kolwezi, Shaba Province, Democratic Republic of Congo
Authors: Roberts A. C. , Paar W. H. , Cooper M. A. , Topa D. , Criddle A. J. , Jedwab J.
Published: July 2002

Verbeekite, ideally PdSe2, monoclinic with space-group choices C2/m, C2 or Cm; a = 6.659(7), b = 4.124(5), c = 4.438(6) Å, ß = 92.76(3)°, V = 121.7(4) Å3; a:b:c = 1.6147:1:1.0761, Z = 2, is a new, very rare, primary mineral, intimately associated with secondary oosterboschite {(Pd,Cu)7Se5}, from the Musonoi Cu-Co-Mn-U mine, near Kolwezi, Shaba Province, Democratic Republic of Congo. Additional associated minerals are Cu- and Pd-bearing trogtalite {(Co,Cu,Pd)Se2}, Se-bearing digenite and Se-bearing covellite. The strongest five lines of the X-ray powder-diffraction pattern {d in Å (I) (hkl)} are: 4.423(30)(001), 3.496 (30)(110), 2.718(100)(111), 1.955(50)(310 and 1.896(50)(12). The mineral has also been identified, as a single anhedral 25 µm-sized grain, from Hope's Nose, Torquay, Devon, England where it is associated with native gold, chrisstanleyite Ag2Pd3Se4, oosterboschite(?), unnamed Pd2HgSe3 and cerussite. At Musonoi, altered verbeekite grains do not exceed 200 µm in size and are anhedral, black, with a black streak and a metallic lustre. The mineral is opaque, brittle, has an uneven fracture, and lacks discernible cleavage. The VHN5 ranges 490–610, mean 550 kp/mm2 (2 indentations), roughly approximating a Mohs' hardness of 5Ý. Dcalc. = 7.211 g/cm3 for the ideal formula. Electron-microprobe analyses (mean of 4 spot analyses) yielded Pd 39.6, Cu 0.5, Se 58.8, total 98.9 wt.%. The empirical formula is (Pd0.99Cu0.02)σ1.01Se1.99, based on Pd+Cu+Se = 3. In plane-polarized reflected light, the mineral is a nondescript grey and is neither pleochroic nor perceptibly bireflectant. Anisotropy is moderate with rotation tints in varying shades of brown. Reflectance spectra and colour values are tabulated. The name honours Dr Théodore Verbeek (1927–1991) who was the first geoscientist to study the Musonoi palladium mineralization in the Democratic Republic of Congo (1955–1967) and who co-discovered this new mineral phase.
An application of the point-dipole model to the problem of optical anomalies in grandite garnets
Authors: Shtukenberg A. G. , Popov D. Yu. , Punin Yu. O.
Published: July 2002

The origin of anomalous birefringence in grossular-andradite (grandite) garnets is considered. Using the point-dipole model we have calculated the anomalous optical indicatrix for four crystals (three from the paper by Takéuchi et al. (1982) and one studied previously by the present authors). The calculated indicatrix is in good agreement with the observed one. This suggests that the origin of anomalous birefringence in grandite garnets is due to Al/Fe ordering. Interrelations between the observed optical indicatrix, the structure of the growing face, the site occupancy in the crystal structure and the calculated optical indicatrix suggest a growth origin of Fe/Al ordering in grandite garnets and confirm the growth dissymmetrization hypothesis.
Fibre growth in wet salt aggregates in a temperature gradient field
Authors: den Brok Bas , Passchier Cees , Sieber Michel
Published: July 2002

Intense fibrosity develops in wet porous NaCl crystal aggregates (grain size 250–500 µm) held in a temperature (T) gradient field (0.5–4°C/mm) at temperatures between 20 and 50–60°C. In situ microscopic observation of the process shows that fibre growth is associated with T-gradient driven motion of tiny gas (air, water vapour) bubbles present in the saturated intercrystalline aqueous NaCl solution. Gas bubbles move through the intercrystalline pore fluid into the cold direction. They only move if they are next to an NaCl crystal; bubbles that are ‘free’ do not move. Each bubble is ‘pushed’ into the cold direction by a growing crystal fibre of the same diameter as the bubble itself. Fibres apparently grow due to oversaturation of the NaCl solution at the hot side of the gas bubble. Crystals dissolve at the cold side of the gas bubbles, apparently by undersaturation of the NaCl solution there. Thus, bubbles dissolve their way through NaCl-crystals and aggregates. Intense fibrosity develops within weeks.
Fe-Mn cation ordering in fayalite–tephroite (FexMn1−x)2SiO4 olivines: a neutron diffraction study
Authors: Redfern S. A. T. , Knight K. S. , Henderson C. M. B. , Wood B. J.
Published: July 2002

Time-of-flight neutron powder diffraction has been employed to determine precise occupancies of the M1 and M2 metal cation sites in synthetic olivines of compositions (Fe0.3Mn0.7)2SiO4, (Fe0.5Mn0.5)2−SiO4, and (Fe0.7Mn0.3)2SiO4. The distribution coefficient for Fe-Mn exchange in these samples has values of 4.864, 3.976, and 4.078, reflecting the preference of Mn2+ for the M2 site, over Fe2+. These results, and the behaviour of the difference in mean bond lengths of the two sites, indicate that, while showing a tendency towards ordering, the composition-dependence of the solid solution is near ideal.
Early Palaeolithic bone diagenesis in the Arago cave at Tautavel,
France
Authors: Quattropani L. , Charlet L. , de Lumley H. , Menu M.
Published: July 2002

Bones from level G in the Arago cave (Tautavel, Southern France, 450 ky) were
analysed using a combination of particle induced X-ray and gamma-ray emission
(PIXE and PIGME) and X-ray diffraction (XRD). Human occupation and guano
production by bats introduced a large amount of phosphate into the cave and as a
result a decarbonated pocket was formed in the sediment, characterized by the
dissolution of clay minerals, calcite and bones, and by the precipitation of
phosphate secondary minerals. The Al released by clay minerals was reprecipitated
as crandallite in the few remaining bones, and as montgomeryite with traces of
crandallite in the surrounding sediments. Bones within the pocket have very high
levels of Al, Fe, F and Zn and often have ‘diffusive’ type U-shaped concentration
profiles. These profiles show that post-mortem uptake of trace elements occurred,
and thus that trace element composition has to be used with care in
palaeonutritional studies but is indicative of local palaeoenvironment. This
uptake is complicated by a large increase in hydroxylapatite crystallinity in
Palaeolithic bones compared to modern or more recent ones, as a result of the
large P influx which occurred in the Arago cave after the sediment
deposition.
MDR1 gene–related clonal selection and P-glycoprotein function and expression in relapsed or refractory acute myeloid leukemia
Authors: van den Heuvel-Eibrink Marry M. , Wiemer Erik A. C. , de Boevere Marjan J. , van der Holt Bronno , Vossebeld Paula J. M. , Pieters Rob , Sonneveld Pieter
Published: July 2002

The expression of P-glycoprotein (P-gp), encoded by theMDR1 gene, is an independent adverse prognostic factor for response and survival in de novo acute myeloid leukemia (AML). Little is known about MDR1 expression during the development of disease. The present study investigated whether MDR1 gene– related clonal selection occurs in the development from diagnosis to relapsed AML, using a genetic polymorphism of the MDR1 gene at position 2677. Expression and function of P-gp were studied using monoclonal antibodies MRK16 and UIC2 and the Rhodamine 123 retention assay with or without PSC 833. No difference was found in the levels of P-gp function and expression between diagnosis and relapse in purified paired blast samples from 30 patients with AML. Thirteen patients were homozygous for the genetic polymorphism ofMDR1 (n = 7 for guanine, n = 6 for thymidine), whereas 17 patients were heterozygous (GT). In the heterozygous patients, no selective loss of one allele was observed at relapse. Homozygosity for the MDR1 gene (GG or TT) was associated with shorter relapse-free intervals (P = .002) and poor survival rates (P = .02), compared with heterozygous patients. No difference was found in P-gp expression or function in patients with AML with either of the allelic variants of the MDR1 gene. It was concluded that P-gp function or expression is not upregulated at relapse/refractory disease and expression of one of the allelic variants is not associated with altered P-gp expression or function in AML, consistent with the fact that MDR1 gene–related clonal selection does not occur when AML evolves to recurrent disease.
A high bone marrow plasma cell labeling index in stable plateau–phase multiple myeloma is a marker for early disease progression and death
Authors: Steensma David P. , Gertz Morie A. , Greipp Philip R. , Kyle Robert A. , Lacy Martha Q. , Lust John A. , Offord Janice R. , Plevak Matthew F. , Therneau Terry M. , Witzig Thomas E.
Published: July 2002

The plasma cell labeling index (PCLI) is a measure of plasma cell proliferative activity and is an important prognostic factor in newly diagnosed multiple myeloma (MM). Occasionally patients have been observed with stable, plateau phase MM with minimal numbers of residual light-chain–restricted monoclonal plasma cells, but a high PCLI. No data are available on the outcomes for such patients. Data from 57 patients with plateau phase MM and a marrow PCLI of more than 1.0% were compared with 105 matched control patients with MM with a marrow PCLI of less than 1.0%. All patients had less than 10% total plasma cells on marrow aspirate and biopsy. The median time to progression and overall survival were 8 months and 20 months, respectively, in the high PCLI group versus 39 months and 56 months, respectively, in the low PCLI group (P < .0001). These findings suggest that a high PCLI in patients with apparently stable, plateau phase MM is an adverse parameter that may predict a short time to disease progression and death.
Molecular and flow cytometric analysis of the Vβ repertoire for clonality assessment in mature TCRαβ T-cell proliferations
Authors: Langerak Anton W. , van den Beemd René , Wolvers-Tettero Ingrid L. M. , Boor Patrick P. C. , van Lochem Ellen G. , Hooijkaas Herbert , van Dongen Jacques J. M.
Published: July 2002

Clonality assessment through Southern blot (SB) analysis ofTCRB genes or polymerase chain reaction (PCR) analysis ofTCRG genes is important for diagnosing suspect mature T-cell proliferations. Clonality assessment through reverse transcription (RT)–PCR analysis of Vβ-Cβ transcripts and flow cytometry with a Vβ antibody panel covering more than 65% of Vβ domains was validated using 28 SB-defined clonal T-cell receptor (TCR)αβ+ T-ALL samples and T-cell lines. Next, the diagnostic applicability of the Vβ RT-PCR and flow cytometric clonality assays was studied in 47 mature T-cell proliferations. Clonal Vβ-Cβ RT-PCR products were detected in all 47 samples, whereas single Vβ domain usage was found in 31 (66%) of 47 patients. The suspect leukemic cell populations in the other 16 patients showed a complete lack of Vβ monoclonal antibody reactivity that was confirmed by molecular data showing the usage of Vβ gene segments not covered by the applied Vβ monoclonal antibodies. Nevertheless, this could be considered indirect evidence for the “clonal” character of these cells. Remarkably, RT-PCR revealed an oligoclonal pattern in addition to dominant Vβ-Cβ products and single Vβ domain expression in many T-LGL proliferations, providing further evidence for the hypothesis raised earlier that T-LGL derive from polyclonal and oligoclonal proliferations of antigen-activated cytotoxic T cells. It is concluded that molecular Vβ analysis serves to assess clonality in suspect T-cell proliferations. However, the faster and cheaper Vβ antibody studies can be used as a powerful screening method for the detection of single Vβ domain expression, followed by molecular studies in patients with more than 20% single Vβ domain expression or large suspect T-cell populations (more than 50%-60%) without Vβ reactivity.
Intravenous injection of apoptotic leukocytes enhances bone marrow engraftment across major histocompatibility barriers
Authors: Bittencourt Marcelo de Carvalho , Perruche Sylvain , Contassot Emmanuel , Fresnay Stéphanie , Baron Marie-Hélène , Angonin Régis , Aubin François , Hervé Patrick , Tiberghien Pierre , Saas Philippe
Published: July 2002

Cross-tolerization of T lymphocytes after apoptotic cell uptake by dendritic cells may be involved in self-tolerance maintenance. Furthermore, immunosuppressive properties are attributed to apoptotic cells. This study evaluated the consequences of apoptotic leukocyte administration in a restrictive engraftment model of murine bone marrow (BM) transplantation. Sublethally irradiated recipients received a limited number of allogeneic BM, with or without irradiated apoptotic leukocytes of different origins. No graft-versus-host disease was observed. Whereas only a low proportion of mice receiving BM cells alone engrafted, addition of apoptotic irradiated leukocytes, independently of the origin (donor, recipient, third-party mice, as well as xenogeneic peripheral blood mononuclear cells), significantly enhanced engraftment. Similar results were obtained after infusion of leukocytes rendered apoptotic by UVB irradiation or by anti-Fas monoclonal antibody stimulation, thus confirming the role of apoptotic cells in engraftment facilitation. Overall, these results suggest that apoptotic leukocytes can nonspecifically facilitate allogeneic BM engraftment. Such a simple approach could be of interest in BM transplantation settings involving an important HLA donor/recipient disparity, a T-cell–depleted graft, or reduced conditioning regimen intensity.
The association of the glycophorin C exon 3 deletion with ovalocytosis and malaria susceptibility in the Wosera, Papua New Guinea
Authors: Patel Sheral S. , Mehlotra Rajeev K. , Kastens William , Mgone Charles S. , Kazura James W. , Zimmerman Peter A.
Published: July 2002

Erythrocyte polymorphisms, including ovalocytosis, have been associated with protection against malaria. This study in the Wosera, a malaria holoendemic region of Papua New Guinea, examined the genetic basis of ovalocytosis and its influence on susceptibility to malaria infection. Whereas previous studies showed significant associations between Southeast Asian ovalocytosis (caused by a 27– base pair deletion in the anion exchanger 1 protein gene) and protection from cerebral malaria, this mutation was observed in only 1 of 1019 individuals in the Wosera. Polymerase chain reaction strategies were developed to genotype individuals for the glycophorin C exon 3 deletion associated with Melanesian Gerbich negativity (GPCΔex3). This polymorphism was commonly observed in the study population (GPCΔex3 frequency = 0.465, n = 742). Although GPCΔex3 was significantly associated with increased ovalocytosis, it was not associated with differences in either Plasmodium falciparumor P vivax infection measured over the 7-month study period. Future case-control studies will determine if GPCΔex3 reduces susceptibility to malaria morbidity.
Five novel mutations in the gene for human blood coagulation factor V associated with type I factor V deficiency
Authors: van Wijk Richard , Nieuwenhuis Karel , van den Berg Marijke , Huizinga Eric G. , van der Meijden Brenda B. , Kraaijenhagen Rob J. , van Solinge Wouter W.
Published: July 2002

Coagulation factor V (FV) plays an important role in maintaining the hemostatic balance in both the formation of thrombin in the procoagulant pathway as well as in the protein C anticoagulant pathway. FV deficiency is a rare bleeding disorder with variable phenotypic expression. Little is known about the molecular basis underlying this disease. This study identified 5 novel mutations associated with FV deficiency in 3 patients with severe FV deficiency but different clinical expression and 2 unaffected carriers. Four mutations led to a premature termination codon either by a nonsense mutation (single-letter amino acid codes): A1102T, K310Term. (FV Amersfoort) and C2491T, Q773Term. (FV Casablanca) or a frameshift: an 8–base pair deletion between nucleotides 1130 and 1139 (FV Seoul1) and a 1–base pair deletion between nucleotides 4291 and 4294 (FV Utrecht). One mutation was a novel missense mutation: T1927C, C585R (FV Nijkerk), resulting in the absence of mutant protein despite normal transcription to RNA. Most likely, an arginine at this position disrupts the hydrophobic interior of the FV A2 domain. The sixth detected mutation was a previously reported missense mutation: A5279G, Y1702C (FV Seoul2). In all cases, the presence of the mutation was associated with type I FV deficiency. Identifying the molecular basis of mutations underlying this rare coagulation disorder will help to obtain more insight into the mechanisms involved in the variable clinical phenotype of patients with FV deficiency.
DUB-2A, a new member of the DUB subfamily of hematopoietic deubiquitinating enzymes
Authors: Baek Kwang-Hyun , Mondoux Michelle A. , Jaster Robert , Fire-Levin Ella , D'Andrea Alan D.
Published: July 2002

Protein ubiquitination is an important regulator of cytokine-activated signal transduction pathways and hematopoietic cell growth. Protein ubiquitination is controlled by the coordinate action of ubiquitin-conjugating enzymes and deubiquitinating enzymes. Recently a novel family of genes encoding growth-regulatory deubiquitinating enzymes (DUB-1 and DUB-2) has been identified.DUBs are immediate-early genes and are induced rapidly and transiently in response to cytokine stimuli. By means of polymerase chain reaction amplification with degenerate primers for theDUB-2 complementary DNA, 3 murine bacterial artificial chromosome (BAC) clones that contain DUB gene sequences were isolated. One BAC contained a novel DUB gene(DUB-2A) with extensive homology to DUB-2. LikeDUB-1 and DUB-2, the DUB-2A gene consists of 2 exons. The predicted DUB-2A protein is highly related to other DUBs throughout the primary amino acid sequence, with a hypervariable region at its C-terminus. In vitro, DUB-2Ahad functional deubiquitinating activity; mutation of its conserved amino acid residues abolished this activity. The 5′ flanking sequence of the DUB-2A gene has a hematopoietic-specific functional enhancer sequence. It is proposed that there are at least 3 members of the DUB subfamily (DUB-1, DUB-2,and DUB-2A) and that different hematopoietic cytokines induce specific DUB genes, thereby initiating a cytokine-specific growth response.