bluuebunny/crossref_metadata_2025 huggingface dataset:
The Reality of Experience: Gibson's Way
Authors: Flach John M. , Holden John G.
Published: July 2002

This paper considers some first principles that might provide a basis for an objective science of experience (presence or immersion). Dimensions that are considered include classical Newtonian measures of the distal stimulus, changes in neural mechanisms reflecting the proximal stimulus, information theoretic measures of the statistical properties of events, and functional properties related to intentions and abilities. Gibson's ecological framework is suggested as a promising functional approach for defining the reality of experience in relation to the problem of designing virtual environments. This approach emphasizes the tight coordination between perception and action and fixes the measurement coordinate system relative to the capacity for action.
Measuring Presence in Virtual Environments: A Presence Questionnaire
Authors: Witmer Bob G. , Singer Michael J.
Published: July 2002

The effectiveness of virtual environments (VEs) has often been linked to the sense of presence reported by users of those VEs. (Presence is defined as the subjective experience of being in one place or environment, even when one is physically situated in another.) We believe that presence is a normal awareness phenomenon that requires directed attention and is based in the interaction between sensory stimulation, environmental factors that encourage involvement and enable immersion, and internal tendencies to become involved. Factors believed to underlie presence were described in the premier issue of Presence: Teleoperators and Virtual Environments. We used these factors and others as the basis for a presence questionnaire (PQ) to measure presence in VEs. In addition we developed an immersive tendencies questionnaire (ITQ) to measure differences in the tendencies of individuals to experience presence. These questionnaires are being used to evaluate relationships among reported presence and other research variables. Combined results from four experiments lead to the following conclusions: the PQ and ITQ are internally consistent measures with high reliability; there is a weak but consistent positive relation between presence and task performance in VEs; individual tendencies as measured by the ITQ predict presence as measured by the PQ; and individuals who report more simulator sickness symptoms in VE report less presence than those who report fewer symptoms.
Neural Fuzzy Agents for Profile Learning and Adaptive Object Matching
Authors: Mitaim Sanya , Kosko Bart
Published: July 2002

A neural fuzzy system can learn an agent profile of a user when it samples user question-answer data. A fuzzy system uses if-then rules to store and compress the agent's knowledge of the user's likes and dislikes. A neural system uses training data to form and tune the rules. The profile is a preference map or a bumpy utility surface defined over the space of search objects. Rules define fuzzy patches that cover the surface bumps as learning unfolds and as the fuzzy agent system gives a finer approximation of the profile. The agent system searches for preferred objects with the learned profile and with a new fuzzy measure of similarity. The appendix derives the supervised learning law that tunes this matching measure with fresh sample data. We test the fuzzyagent profile system on object spaces of flowers and sunsets and test the fuzzy agent matching system on an object space of sunset images. Rule explosion and data acquisition impose fundamental limits on the system designs.
Approximate Life‐Cycle Assessment of Product Concepts Using Learning Systems
Authors: Sousa Inês , Wallace David , Eisenhard Julie L.
Published: July 2002

Parametric life‐cycle assessment (LCA) models have been integrated with traditional design tools and used to demonstrate the rapid elucidation of holistic, analytical trade‐offs among detailed design variations. A different approach is needed, however, if analytical environmental assessment is to be incorporated in very early design stages. During early stages, there may be competing product concepts with dramatic differences. Detailed information is scarce, and decisions must be made quickly.

This article explores an approximate method for providing preliminary LCAs. In this method, learning algorithms trained using the known characteristics of existing products might allow environmental aspects of new product concepts to be approximated quickly during conceptual design without defining new models. Artificial neural networks are trained to generalize on product attributes, which are characteristics of product concepts, and environmental inventory data from pre‐existing LCAs. The product design team then queries the trained artificial model with new high‐level attributes to quickly obtain an impact assessment for a new product concept. Foundations for the learning system approach are established, and then an application within the distributed object‐based modeling environment (DOME) is provided. Tests have shown that it is possible to predict life‐cycle energy consumption, and that the method could be used to predict solid waste, greenhouse effect, ozone depletion, acidification, eutrophication, winter and summer smog.
A Dutch Approach to the European Directive on Integrated Pollution Prevention and Control: Using Life‐Cycle Assessment for the Integrated Assessment of Technologies
Authors: Breedveld Leo
Published: July 2002

In light of the European Directive on Integrated Pollution Prevention and Control (IPPC Directive), traditional environmental regulation can be improved using the framework of industrial ecology. The objective of the IPPC Directive is to achieve a high level of protection of the environment as a whole (Article 1) by applying the best available techniques (BAT). In essence, the IPPC Directive obliges member states of the European Union to include considerations such as resources, energy, waste, and multimedia emissions when permitting industrial installations. This is a marked contrast to traditional environmental regulation that focuses on individual media of an individual site. In order to take all considerations into account, an integrated assessment of technologies is needed, for which a standard method is currently lacking.

In this article, a systematic approach is introduced for the integrated assessment of IPPC technologies using life‐cycle assessment (LCA), a form of environmental assessment that can be broadened to an overall assessment of environmental, economic, and social aspects. This systematic approach has proven to be successful for the environmental assessment of the described cases. It is suggested here that weighting can be omitted for the evaluation of IPPC technologies. Leaving the weighting step to competent authorities of member states and allowing them to consider local issues provides maximum opportunity for the subsidiarity and flexibility principles of the IPPC Directive.
Bringing in the “Other Side”: New Scholarship on the Vietnam Wars
Authors: Logevall Fredrik
Published: July 2002

The literature on the Vietnam War is large and getting larger. Much of it is ex-traordinarily valuable to students of the conflict. Until recently, however, the literature suffered from a U.S.-centric focus and a tendency to look solely at decision making in Washington. Too few studies have placed U.S. decision making into its wider international context;fewer still have given a voice to the “other side,” the Vietnamese who fought so long and hard to defeatfirst the French and then the South Vietnamese government and its American al-lies. The picture is beginning to change, however, and this article examines several new books that illuminate the Vietnamese side. Although many of the most important findings in these works come not from Vietnamese docu-mentary sources but from Western archives and publications, the authors ap-pear to have made effective use of what Vietnamese material is available. The volumes are worthy entries in the international history of the Indochina wars, and they help set the agenda for future research.
The New History of Cold War Alliances
Authors: Mastny Vojtech
Published: July 2002

Efforts to document the full histories of the Nor h Atlantic Treaty Organiza-tion (NATO) and the Warsaw Pact are still hindered by key obstacles. NATO documents from 1965 onward remain closed to researchers, as do many War-saw Pact military records that were carted off to Moscow in 1991. Despite these gaps, newly declassified materials from both East and West have shed light on how the two alliances helped shape the Cold War. This article takes note of some of the more important recent scholarship on NATO and the Warsaw Pact.
Risky Business: Insurance Companies in Global Warming Politics
Authors: Paterson Matthew
Published: July 2002

The paper describes and analyzes the responses of insurance companies to global climate politics. It shows how these responses failed to live up to the initial optimism of environmentalists and commentators about the potential of the involvement of insurers in climate politics. It then attempts to explain why insurers have disappointed environmentalist expectation. It shows that part of this is due to constraints and opportunities within the insurance business itself. But it then shows how much of the reason is to do with a simplistic understanding by environmentalists of the power of insurers. Examining the political-economic contexts in which insurance companies operate provides a clearer picture as to the limits to the role insurers can play in mitigating global warming.
Matrimonial Gifts In Early Islamic Egypt
Authors: Rapoport Yossef
Published: July 2002

The mahr or sadāq is the only marriage gift required under Islamic law. But Islamic law did not necessarily determine actual marriage settlements, even in early Muslim societies. In this essay, I compare the early Islamic legal literature with the pattern of matrimonial gifts recorded in marriage contracts and divorce deeds preserved from early Islamic Egypt. In marriage settlements recorded in the papyri, the groom gave a sadāq that was divided into advance and deferred portions, and brides brought to the marriage a counterpart dowry (jihāz or shiwār). These marriage settlements, which were common to Muslims, Copts and Jews, resembled the Egyptian marriage settlements of late antiquity. The Islamic legal literature preserves the objections of contemporary jurists, including Mālik, to these Egyptian practices, which they initially regarded as an objectionable innovation. Eventually, the local traditions were incorporated, albeit with modifications, into the legal discourse.
BEHAVIORAL SAMPLING IN THE FIELD: CONTINUOUS FOCAL VERSUS FOCAL INTERVAL SAMPLING
Authors: Rose Lisa
Published: July 2002

I compared data collection rates for continuous and interval focal samples during a two-year, single-observer field study of white-faced capuchins (Cebus capucinus) in Costa Rica. I also compared the basic activity budgets generated by the two sampling methods, estimates of numbers in proximity, and rates at which additional ad libitum observations could be recorded. I collected 1238 hours of focal data (620 hr continuous, 618 hr interval). I found focal interval sampling to be 25% more time efficient, despite higher rate of sample loss, partly because interval samples are easier to obtain in difficult conditions. I found no evidence that interval sampling provided better opportunities for ad libitum observation than continuous sampling. Overall, the two methods yielded similar estimates of activity budgets. However, continuous sampling resulted in somewhat higher estimates of time spent eating, while interval data gave somewhat lower estimates of time spent foraging (looking for or handling food items) and moving, resulting in lower estimates of foraging success. Interval sampling also yielded slightly lower estimates of time spent vigilant. I attribute these patterns to two major effects: (1) errors of omission (missing rare behaviors of short duration) during interval samples and (2) a greater tendency toward conditional sampling bias (under-representing behaviors due to difficult sampling conditions such as rapid travel) under a continuous sampling regime.
CHEMICAL PREDATOR INSPECTION AND ATTACK CONE AVOIDANCE IN A CHARACIN FISH: THE EFFECTS OF PREDATOR DIET
Authors: Brown Grant , Schwarzbauer Erica
Published: July 2002

Many prey organisms will approach (inspect) a potential predator, primarily to assess local risk of predation. It has been argued that by avoiding the head region of predators during inspections, prey can reduce the risks associated with such behaviour (attack cone avoidance). Prior experiments, however, have not incorporated the combined chemical and visual predator cues. We conducted laboratory experiments to determine the effects of combined predator dietary (chemical) and visual cues on the form and location of predator inspection visits by glowlight tetras (Hemigrammus erythrozonus). Tetras were exposed to a live cichlid predator (Cichlasoma octofasciatum) which had been fed tetras (with alarm pheromone), swordtails (Xiphophorus helleri; lacking Ostariophysan alarm pheromones) or food deprived. There was no significant difference in the overall rate of predator inspection by tetras to tetra-fed, swordtail-fed or food deprived cichlids. There was, however, a significant effect of predator diet on the size of inspection shoals and the location of inspections. Tetras inspected a tetrafed predator in significantly smaller groups, more often as singletons and directed a greater proportion of their inspections towards the tail of the predator. Tetras exposed to swordtail-fed or food deprived cichlids inspected in larger groups and directed more inspections towards the head of the predator. When the predator dietary cue contained tetra alarm pheromone, there was a significant increase in the attack latency by predators. Taken together, these data suggest that tetras use both chemical and visual predator cues during inspection visits and will modify their behaviour based on the presence or absence of conspecific alarm pheromone in the diet of a potential predator.
Hirschmanniella caribbeana sp. n. and new records of Pratylenchus spp. (Pratylenchidae: Nematoda) from Guadeloupe, French West Indies
Authors: Berg Esther Van Den , Quénéhervé Patrick
Published: July 2002

Hirschmanniella caribbeana sp. n. is described and figured from mangrove
vegetation from Guadeloupe. Females are characterised by the tail terminus
having two lateral peg-like projections with a smaller, irregular
intermediate projection, a low, rounded lip region with five to six annuli,
a 17-20 μm long stylet, areolated lateral fields, intestine not overlapping
the rectum and phasmids situated at midtail. Males numerous, similar to
females except for sexual characters. Juvenile tail ends in a single, thin,
pointed mucro. Notes, morphometrics, descriptions and figures are given for
Pratylenchus flakkensis, P. jordanensis, P. teres and P. loosi all new
records for this region. Hirschmanniella caribbeana sp. n. provenant de
mangrove de Guadeloupe est décrit et illustré. Les femelles sont
caractérisées par l’extrémité de la queue munie de deux projections
latérales digitées encadrant une autre projection plus petite et
irrégulière, une région céphalique basse, arrondie, comportant cinq à six
anneaux, un stylet long de 17-20 μm, des champs latéraux aréolés, l’intestin
ne recouvrant pas le rectum et les phasmides situées au milieu de la queue.
Les mâles, nombreux, sont semblables aux femelles à l’exception des
caractères sexuels. L’extrémité de la queue des juvéniles porte un mucron
simple, pointu et fin. Des notes, des mensurations, des descriptions et
illustrations sont données pour Pratylenchus flakkensis, P. jordanensis, P.
teres et P. loosi, toutes espèces signalées pour la première fois dans cette
région.
Transovarial transmission of symbionts in Xiphinema brevicollum (Nematoda: Longidoridae)
Authors: Coomans August , Claeys Myriam , Vandekerckhove Tom T.M.
Published: July 2002

Transovarial transmission of bacterial symbionts in Xiphinema brevicollum was examined by means of electron microscopical- and fluorescence microscopical observations of intra-uterine and freshly laid non-embryonated eggs, as well as of embryonated eggs. The symbionts are mainly aggregated near one of the egg poles and this is observed in non-embryonated as well as in embryonated eggs. The bacteria are present in intestinal cells of first stage juveniles that are still enclosed by the egg-shell. In subsequent juvenile developmental stages their number increases and the intestinal cells are filled with the symbionts. Bacteria were not present in the genital primordium. It is hypothesised that the aggregated symbionts at one of the egg poles become enclosed in the E founder cell during embryogenesis and subsequently are distributed to the endodermal daughter cells. The bacteria become enclosed in the ovarial wall through an unknown mechanism only during the later stages of gonad development. Transmission transovarienne des symbiontes de Xiphinema brevicollum (Nematoda: Longidoridae) - La transmission transovarienne des symbiontes bactériens de Xiphinema brevicollum a été étudiée par observations en microscopie électronique et à fluorescence d'œufs non embryonnés, encore contenus dans l'utérus ou fraichement pondus, et d'œufs embryonnés. Les symbiontes sont en majorité agrégés à l'un des pôles de l'œuf, que celui-ci soit embryonné ou non. Les bactéries sont présentes dans les cellules intestinales du premier stade juvénile encore contenu à l'intérieur de la coque de l'œuf. Chez les stades juvéniles ultérieurs leur nombre croît et les cellules intestinales sont remplies de symbiontes. Ces bactéries sont absentes du primordium génital. L'hypothèse est avancée que les symbiontes agrégés à l'un des pôles de l'œuf se retrouvent, au cours de l'embryogenèse, dans la cellule fondatrice E et sont par la suite répartis dans les cellules endodermiques filles. Les bactéries ne se retrouvent dans la paroi ovarienne que lors des derniers stades du développement de la gonade par un mécanisme encore inconnu.
Molecular characterisation of Heterorhabditis indica isolates from India, Kenya, Indonesia and Cuba
Authors: Stack Colin , Easwaramoorthy Subbana , Metha Usha , Downes Martin , Griffin Christine , Burnell Ann
Published: July 2002

Isolates of Heterorhabditis were identified as H. indica using the following
molecular diagnostic features: hybridisation to a H. indica specific
satellite DNA probe; AluI and MboI restriction profiles of the rDNA ITS PCR
product and the AluI profile of the rDNA IGS PCR product. The Kenyan
isolates represent a distinct subgroup of H. indica. These isolates lacked
one of the two HinfI restriction sites which are present in the rDNA ITS
product of all the other isolates tested and they also differed from other
H. indica isolates in their rDNA IGS HaeIII restriction profile. The Indian
isolates are interfertile. The Kenyan isolates are interfertile but only one
Kenyan isolate, Ki3, produced viable progeny when crossed with H. indica
LN2. The four Indonesian isolates are interfertile, but only one Indonesian
isolate (INA H1) produced viable hybrids when crossed with H. indica LN2.
INA H1 was also interfertile with the Kenyan isolate Ki3. Caractérisation
moléculaire d'isolats d'Heterorhabditis indica provenant d'Inde, du Kenya,
d'Indonésie et de Cuba - Des isolats d'Heterorhabditis ont été identifiés
comme H. indica par l'utilisation des techniques de caractérisation
moléculaire suivantes: hybridation avec une sonde spécifique du DNA
satellite de H. indica, produits des profils de restriction par PCR de l'ITS
du rDNA par AluI et MboI et produit de PCR de l'IGS du rDNA par AluI. Les
isolats keniyans constituent un sous-groupe distinct d'H. indica. Un des
deux sites de restriction de HinfI, présent dans les produits de l'ITS du
rDNA de tous les autres isolats étudiés, est absent dans ces isolats qui
différaient également dans leurs profils de restriction de l'IGS du rDNA par
HaeIII. Les isolats d'Inde sont interfertiles. Les isolats kenyans sont
inter-fertiles mais un seul de ces isolats, Ki3, a produit une descendance
viable après croisement avec H. indica LN2. Les quatre isolats indonésiens
sont interfertiles, mais un seul d'entre eux (INA H1) a produit des hybrides
viables après croisement avec H. indica LN2. INA H1 a été également
interfertile avec l'isolat kenyan Ki3.
Two Dubious Third Reich Diaries
Authors: Turner Henry Ashby
Published: July 2002

Diaries justly rank among the most valuable sources for historians. Committed to paper soon after the events and thoughts they record, diaries are free of the knowledge about what occurs afterward or only later takes on significance that adulterate memoirs and render them far more problematic for historians. It is therefore worthy of a cautionary note when historians confuse examples of the two genres. That has frequently occurred in the case of Bella Fromm's Blood and Banquets: A Berlin Social Diary. Published nearly sixty years ago in the form of a diary; it has been used as such in numerous historical studies of the Third Reich. A more recent book that poses problems similar to Fromm's and that has also been used by historians as a source for the Nazi period, is The Berlin Diaries, 1940–1945, attributed posthumously to Marie “Missie” Vassiltchikov.
Hydromechanical effects: (II) on the water-Na-smectite system
Authors: Al-mukhtar M. , Qi Y. , Alcover J . -F. , Conard J . , Bergaya F.
Published: July 2002

The localization and number of the different types of water in two Na-smectites (Laponite and hectorite) were studied as a function of the hydromechanical stresses applied. Water volume variation was obtained by macroscopic oedometric tests. Thermogravimetric analysis (TGA), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) were used to study water-smectite interactions. The TGA results show that the bulk water content decreases while the adsorbed water content remains practically constant with increasing mechanical stress; hectorite adsorbs less water than Laponite at low hydraulic stress. The proportion of adsorbed water obtained by NMR confirms the TGA data. The interlamellar space and the equivalent water layers decrease with increasing mechanical stress and is always lower in hectorite than in Laponite. Hydromechanical effects on the water-Na-smectite system are in agreement with microtexture changes measured by porosimetry. Differences in the properties of the two clays can be attributed to the higher extension of the layers in hectorite compared with Laponite.
Weathering of smectite and illite- smectite under temperate climatic conditions
Authors: Šucha V. , Środoń J. , Clauer N. , Elsass F. , Eberl D. D. , Kraus I. , Madejová J.
Published: July 2002

Weathering profiles developed on the top surface of a bentonite (containing Al-Mg montmorillonite) and a K-bentonite (containing mixed-layer illite-smectite (I-S)) under Central European temperate conditions were studied by XRD, HRTEM, FTIR, K-Ar and chemical analyses. Weathering of montmorillonite results in the decrease of cation exchange capacity (CEC), total surface area and Mg content. The process is interpreted as montmorillonite dissolution and precipitation of amorphous SiO2. Weathering of I-S produces an increase in CEC and total surface area. The XRD data suggest dissolution of I-S and appearance of smectite as a separate phase at intermediate depths. The fixation of ammonium is documented in the topmost sample. In both profiles, abundant aeolian contaminants, including mica, were identified and their migration was traced using K-Ar dating.
Thermal conductivity of selected claystones and mudstones from England
Authors: Midttømme K. , Roaldset E. , Aagaard P.
Published: July 2002

The claystones and mudstones investigated are London Clay, Fullers Earth, Oxford Clay and Kimmeridge Clay. The thermal conductivities were measured using a divided bar apparatus and the values measured perpendicular to layering ranged from 0.68 to 0.97 W/mK. Comparative measurements of thermal conductivities were carried out by the needle probe method and Middleton's method. Deviations of up to 50% were obtained between the needle probe and the divided bar method. The thermal conductivities estimated from the geometric mean model based on mineralogy and water content ranged from 0.87 to 2.01 W/mK, considerably higher than the measured values. A correlation was found between the grain size distributions of the samples and the measured thermal conductivities. This textural effect on the thermal conductivity is assumed to be the main reason for the low measured values and the lack of correlation between the measured and the calculated values.
Partial dehydration of laumontite: thermodynamic constraints and petrogenetic implications
Authors: Neuhoff P. S. , Bird D. K.
Published: July 2002

Laumontite is a common zeolite mineral indicative of low-grade metamorphism of lavas and volcaniclastic sediments. Stoichiometric laumontite (CaAl2Si4O12·4.5H2O) dehydrates in air at 298.15 K, 1 bar to leonhardite (CaAl2Si4O12·3.5H2O) via loss of water from the W1 crystallographic site. Consideration of reported X-ray diffraction and calorimetric data indicates that the standard molal volume and entropy for dehydration of laumontite to leonhardite + liquid water are ∼13 cc/mol and ∼8 cal/molK, respectively, at 298.15 K, 1 bar. Equilibrium between laumontite and leonhardite occurs at 70 to 80% relative humidity at 298.15 K, 1 bar, corresponding to a standard molal Gibbs energy and enthalpy of reaction of ∼170±40 and ∼2630±100 cal/mol, respectively. Calculated univariant equilibrium for this reaction is nearly linear from 46±3°C at 1 bar to 235±3°C at 5000 bar. Comparison of geological observations with these results suggests that laumontite forms as ‘leonhardite’ during metamorphism and diagenesis. Consideration of ‘leonhardite’, instead of laumontite, in low-grade metamorphic phase relations facilitates prediction of the relative stabilities of zeolites in natural and geologic systems, where calculated entropies of reaction incorrectly predict that assemblages bearing fully hydrated laumontite are stable at lower temperatures than the zeolites heulandite and stilbite.
Mineral chemistry of a peralkaline combeite-lamprophyllite nephelinite from Oldoinyo Lengai, Tanzania
Authors: Dawson J. B. , Hill P. G.
Published: July 2002

A peralkaline nephelinite lava ([Na+K]/Al 2.15) from the active carbonatite volcano Oldoinyo Lengai, contains combeite, Ba lamprophyllite, a phase with affinities to delhayelite, CeSrNb perovskite, a CaNa phosphate high in Sr, Ba and K, and peralkaline glass; in addition to Fe-rich nepheline, aegirine-rich clinopyroxene and FeK-rich sodalite. The high alkali concentrations relative to alumina in the bulk rock could not have been achieved by fractionational crystallisation of the known Al-rich phenocryst phases (nepheline and sodalite) and some other process must be invoked.
Two morphologies of pyrophanite in Mn-rich assemblages, Gangpur Group, India
Authors: Nayak B. R. , Mohapatra B. K.
Published: July 2002

Pyrophanite is widely distributed in metamorphic Mn-rich rock assemblages of the Gangpur Group, India. It occurs in two distinct habits: as an independent phase, and as an exsolved phase within hematite. The well developed large sized crystals coexist with spessartine in Mn-silicate facies rocks. In contrast, the exsolved crystals occur as fine needle/bleb-like crystallites intergrown with hematite in Mn-silicate-oxide facies rocks. Compositionally the exsolved crystals are enriched in iron, present in both the ferric and ferrous states. The two morphologies of pyrophanite attest to their formation under different environmental conditions. The independent pyrophanite is formed from a Mn-Ti rich precursor under low oxygen fugacity conditions while the hematite-pyrophanite intergrowth evolved from an Fe-Mn-Ti rich precursor under higherfO2conditions.
Composition of tetrahedrite-tennantite and ‘schwazite’ in the Schwaz silver mines, North Tyrol, Austria
Authors: Arlt T. , Diamond L. W.
Published: July 2002

The hydrothermal fahlore deposits of the Schwaz-Brixlegg district have been mined for silver and copper over many centuries and are famous as the type locality of the mercurian fahlore variety ‘schwazite’. The ore is dominantly monomineralic fahlore and occurs as stratabound, discordant vein, and breccia bodies over a 20 km belt hosted mostly by the Devonian Schwaz Dolomite. The structural style of the mineralization is similar to that of Mississippi Valley type deposits.

This study presents the first electron microprobe analyses of the ores and reveals wide variations in fahlore compositions, from 35 to 100 wt.% tetrahedrite end-member in the solid solution series with tennantite. Sb and Zn contents vary between 12.1–28.0 wt.% and 0.1–7.6 wt.%, respectively. Silver contents average 0.5 wt.% and range up to 2.0 wt.%. In the breccia-hosted ores these variations clearly result from a temporal evolution in the ore-forming hydrothermal system: main-stage tetrahedrite is replaced by assemblages of Sb-, Fe-, and Ag-enriched tetrahedrite + enargite, with minor sphalerite ± stibnite ± cuprian pyrite (≤ 25 wt.% Cu). These reactions are deduced to result from either increases in aqueous sulphur activity or falling temperature. Earlier workers recognized strong geographic zonation of fahlore compositions, but our microprobe analyses refute these contentions.

The 1167 new microprobe analyses of 51 fahlore samples collected underground or obtained from museum collections yield an average Hg content of 1.8 wt.%, and a maximum of 9.4 wt.%. According to modern nomenclature, not even the highest Hg value qualifies as ‘schwazite’. Moreover, it appears that the original and only analysis of ‘schwazite’, reporting 15.6 wt.% Hg (Weidenbusch, 1849), was erroneously performed on a polymineralic aggregate, rather than on a monomineralic fahlore. We conclude that the Schwaz-Brixlegg fahlores are in fact not unusually rich in mercury, and that in all probability there is not, and never has been, any ‘schwazite’ at Schwaz.
A scanning electron microscope study of post-depositional changes in the
northeast Niğde ignimbrites, South Central Anatolia, Turkey
Authors: Yurtmen S. , Rowbotham G.
Published: July 2002

The ignimbrites of the northeast Niğde area, which are subdivided into the
Lower, Middle and Upper ignimbrites on the basis of their compositional and
stratigraphical characteristics, display textural variations from the base to the
top. A large proportion of these ignimbrites have been altered and recrystallized
by the processes of compaction, welding and devitrification, and as a result of
volatile movement. The alteration and recrystallization processes include four
stages: hydration, glassy and spherulitic stages accompanied by vapour-phase
crystallisation. In the early phases of devitrification, detailed shard shapes are
easily recognisable with the scanning electron microscope, but as alteration
proceeds clarity of detail disappears because compaction results in collapse of
the structure of the rock. Spherulitic and vapour-phase crystallisation usually
involves the growth of alkali feldspar and cristobalite. These later stages are
more common in the Upper Ignimbrite than the Middle and Lower
ignimbrites.
Extreme chemical variation in complex diamonds from George Creek, Colorado: a SIMS study of carbon isotope composition and nitrogen abundance
Authors: Fitzsimons I. C. W. , Harte B. , Chinn I. L. , Gurney J. J. , Taylor W. R.
Published: July 2002

Diamonds from George Creek, Colorado, preserve complex intergrowth textures between two major growth generations: homogeneous diamond with yellow-buff cathodoluminescence (CL); and diamond with blue-green CL and local growth zonation. Secondary-ion mass spectrometry (SIMS) has revealed large variations in N concentration and C isotope composition within these diamonds. Even within single stones, N contents and δ13C values can vary from 0 to 750 ppm and 0 to −20‰ respectively. These variations are similar to those recorded elsewhere for entire diamond suites. The CL characteristics correlate directly with N: diamond with yellow-buff CL has uniform N contents, whereas the zoned diamond has bright blue CL bands with high N (50–750 ppm) and dark blue or green CL bands with low N (0–20 ppm). These bands are too narrow (10–5 µm) for analysis by IR spectroscopy. δ13C also varies between the two growth generations in any one diamond plate, and to a lesser extent within these generations, but shows no consistent correlations with either CL or N. The George Creek stones preserve evidence of extreme temporal and/or spatial variations in both δ13C and N concentrations during the period of diamond growth, but the factors controlling N content during diamond growth did not control δ13C.
Synthesis and release of B-lymphocyte stimulator from myeloid cells
Authors: Nardelli Bernardetta , Belvedere Ornella , Roschke Viktor , Moore Paul A. , Olsen Henrik S. , Migone Thi Sau , Sosnovtseva Svetlana , Carrell Jeffrey A. , Feng Ping , Giri Judith G. , Hilbert David M.
Published: July 2002

B-lymphocyte stimulator (BLyS) is a recently identified novel member of the tumor necrosis factor ligand superfamily shown to exist in a membrane-bound and soluble form. BLyS was found to be specifically expressed on cells of myeloid lineage and to selectively stimulate B-lymphocyte proliferation and immunoglobulin production. The expression of a cytokine involved in potentiation of humoral immune responses, such as BLyS, is expected to be strictly controlled. The goal of the present study was to examine regulation of BLyS levels in monocytic cells in response to cytokines and during their differentiation to macrophages and dendritic cells. The presence of BLyS on the cell surface and in the culture medium of both normal blood monocytes and on tumor cells of myelomonocytic origin was demonstrated. BLyS gene expression and levels of membrane-associated and soluble BLyS were found to be regulated by cytokines, in particular interferon (IFN)-γ and to a lesser extent interleukin-10 (IL-10). The expression of BLyS on monocyte membranes was retained following differentiation into macrophages, but detection on the surface of monocyte-derived dendritic cells required stimulation with IFN-γ. Both IFN-γ and IL-10 enhanced the release of soluble BLyS that was active in B-cell proliferation assays. Cells transfected with BLyS complementary DNA mutated in a predicted cleavage site failed to release BLyS into the culture medium, thereby suggesting that soluble BLyS was derived from the membrane form. These results provide further support for an important role for BLyS expressed in myeloid cells in B-cell expansion and antibody responses.
Multiple signaling pathways regulate NF-κB–dependent transcription of the monocyte chemoattractant protein-1 gene in primary endothelial cells
Authors: Goebeler Matthias , Gillitzer Reinhard , Kilian Karin , Utzel Kathrin , Bröcker Eva-Bettina , Rapp Ulf R. , Ludwig Stephan
Published: July 2002

The cytokine-induced C-C chemokine monocyte chemoattractant protein-1 (MCP-1) is an important regulator of leukocyte recruitment to sites of inflammatory challenge. Here, it is demonstrated that the widely distributed contact hapten NiCl2, like tumor necrosis factor α (TNFα), induces monocyte-chemoattractant activity in primary human endothelial cells via induction of MCP-1. NiCl2 rapidly activated mitogen-activated protein (MAP) kinase p38, and inhibition of p38 partially blocked NiCl2-induced MCP-1 messenger RNA and protein expression. Both NiCl2- and TNFα-induced MCP-1 synthesis was sensitive to D609, an inhibitor of phosphatidylcholine-dependent phospholipase C (PC-PLC). NiCl2-induced MCP-1 synthesis required activation of NF-κB since mutation of NF-κB–binding sites in the promoter resulted in complete loss of inducible promoter activity. Consistent with that finding, stimulation with NiCl2 or TNFα activated IκB kinase-β (IKKβ), and transient transfection of dominant-negative IKKβ strongly inhibited NiCl2- and TNFα-induced MCP-1 expression. However, D609 and the specific p38 inhibitor SB202190 did not affect NiCl2- and TNFα-induced IKKβ activation, NF-κB DNA-binding activity, or transcriptional activity of a Gal4p65 fusion protein. This indicates that p38- and PC-PLC–dependent pathways directly regulate the transcriptional activity of NF-κB factors in the transcriptional complex. Consistent with that, inhibition of p38 blocked enhanced transcriptional activity induced by the transcriptional coactivator p300. Thus, it was concluded that at least 3 independent pathways regulate MCP-1 expression in endothelial cells. Its induction requires activation of the IKKβ/IκBα/NF-κB signaling pathway, resulting in nuclear accumulation of p65 and subsequent recruitment of cofactors. Proper assembly and activity of this transcriptional complex is further modulated by the p38 MAP kinase cascade and a PC-PLC–dependent pathway.
Functional requirements for phenotypic correction of murine β-thalassemia: implications for human gene therapy
Authors: Persons Derek A. , Allay Esther R. , Sabatino Denise E. , Kelly Patrick , Bodine David M. , Nienhuis Arthur W.
Published: July 2002

As initial human gene therapy trials for β-thalassemia are contemplated, 2 critical questions important to trial design and planning have emerged. First, what proportion of genetically corrected hematopoietic stem cells (HSCs) will be needed to achieve a therapeutic benefit? Second, what level of expression of a transferred globin gene will be required to improve β-thalassemic erythropoiesis? These questions were directly addressed by means of a murine model of severe β-thalassemia. Generation of β-thalassemic mice chimeric for a minority proportion of genetically normal HSCs demonstrated that normal HSC chimerism levels as low as 10% to 20% resulted in significant increases in hemoglobin (Hb) level and diminished extramedullary erythropoiesis. A large majority of the peripheral red cells in these mice were derived from the small minority of normal HSCs. In a separate set of independent experiments, β-thalassemic mice were bred with transgenic mice that expressed different levels of human globins. Human γ-globin messenger RNA (mRNA) expression at 7% of the level of total endogenous α-globin mRNA in thalassemic erythroid cells resulted in improved red cell morphology, a greater than 2-g/dL increase in Hb, and diminished reticulocytosis and extramedullary erythropoiesis. Furthermore, γ-globin mRNA expression at 13% resulted in a 3-g/dL increase in Hb and nearly complete correction of red cell morphology and other indices of inefficient erythropoiesis. These data indicate that a significant therapeutic benefit could be achieved with expression of a transferred globin gene at about 15% of the level of total α-globin mRNA in patients with severe β-thalassemia in whom 20% of erythroid precursors express the vector genome.
Molecular genetic basis of porcine histo-blood group AO system
Authors: Yamamoto Fumiichiro , Yamamoto Miyako
Published: July 2002

Histo-blood group A and B antigens are oligosaccharide antigens important in transfusion and transplantation medicine. The final steps in the synthesis of these antigens are catalyzed by glycosyltransferases encoded by the functional alleles at the ABO locus. Humans have 3 major alleles (A, B, and O), whereas pigs are known to have only A and O alleles. This paper reports the molecular genetic basis of the porcine AO system. The porcine A gene is homologous to the ABO genes in humans and other species. It encodes an α1 → 3N-acetyl-D-galactosaminyltransferase that synthesizes A antigens. Southern hybridization experiments using a porcine A gene coding-sequence probe failed to identify a corresponding homologous sequence in genomic DNA from group O pigs, thus suggesting a major deletion in the O gene. Therefore, inadvertent activation of a silent O gene seems unlikely in porcine organs xenotransplanted into humans.
Investigation of human spleen dendritic cell phenotype and distribution reveals evidence of in vivo activation in a subset of organ donors
Authors: McIlroy Dorian , Troadec Christelle , Grassi Fernanda , Samri Assia , Barrou Benoı̂t , Autran Brigitte , Debré Patrice , Feuillard Jean , Hosmalin Anne
Published: July 2002

Although the mouse spleen dendritic cell (DC) is perhaps the most intensively studied DC type, little has been published concerning its human equivalent. In this report, rare event flow cytometry and in situ immunofluorescence were used to study the surface phenotype and distribution of HLA-DR+CD3−14−16−19− human spleen DC. Spleens from organ donors with different clinical histories were used. Most (81% ± 9%; n = 14) spleen DCs expressed high levels of the integrin CD11c. CD11c+ DCs were distributed in 3 distinct regions—the peri-arteriolar T-cell zones, the B-cell zones, and the marginal zone, where they formed a ring of cells surrounding the white pulp, just inside a ring of CD14+ red pulp macrophages, apparently more regularly organized than the previously described marginating DC population in the mouse spleen. The T-cell zones contained CD86+ DCs, among which a subpopulation expressed CD83. These mature/activated CD86+DCs represented a minority (12% ± 8%) of total spleen DCs in most organ donors: most spleen DCs are immature. In 3 of 18 (17%) donors, however, most (54%-81%) of spleen DCs were CD86+, suggesting that in vivo DC activation had occurred. In one donor, a radical shift in DC distribution from the marginal zone to the T-cell zones was also observed. This activation of spleen DCs in vivo was reminiscent of the effects of experimental microbial product injection in mice, and it seemed to correlate with bacterial infection or multiple trauma.
Stressed apoptotic tumor cells express heat shock proteins and elicit tumor-specific immunity
Authors: Feng Hanping , Zeng Yi , Whitesell Luke , Katsanis Emmanuel
Published: July 2002

In attempting to develop effective anticancer immunotherapies, the relative ability of apoptotic cells to induce an immune response remains an important but controversial consideration. A novel gene-transfer approach was used by which rapid induction of pure apoptosis can be selectively achieved in a transfected tumor cell population following exposure to a semisynthetic dimerizing ligand, AP20187. Inoculation of BALB/c mice with apoptotic and viable 12B1-D1 leukemia cells, at a 12:1 ratio subcutaneously, led to early tumor growth. Heat stress up-regulated the expression of membrane heat shock proteins (HSP72 and HSP60) on apoptotic 12B1-D1 cells, and stressed apoptotic cells were capable of generating a T-cell–mediated specific antitumor response. Pulsing of stressed apoptotic leukemia cells onto syngeneic dendritic cells resulted largely in rejection of coinjected viable 12B1-D1 cells. Mice rejecting the primary 12B1-D1 inoculum were immune to the same but not to a different leukemia challenge. Our findings indicate that tumor immunogenicity is dependent on whether cells are stressed before apoptosis induction and suggest that the immune system is capable of distinguishing between stressed and nonstressed cells undergoing programmed cell death.
Raised blast glutathione levels are associated with an increased risk of relapse in childhood acute lymphocytic leukemia
Authors: Kearns Pamela R. , Pieters Rob , Rottier M. M. Antoinette , Pearson Andrew D. J. , Hall Andrew G.
Published: July 2002

A preliminary study has linked raised blast glutathione levels with chemoresistance in acute myeloid and lymphoblastic leukemia in adults and children. In this study, therefore, the relationship between leukemic blast glutathione levels and prognosis in childhood acute lymphoblastic leukemia (ALL) was investigated. A total of 77 childhood ALL samples were analyzed, 62 at initial presentation and 15 at relapse. A 20-fold interindividual variation in glutathione levels at presentation (median, 6.54 nmol/mg protein; range, 1.37 to 27.9) was demonstrated. The median level in T-lineage ALL was 2.3-fold higher than in B-lineage ALL (Mann-Whitney test,P < .0001). There was a significant correlation between presenting white cell count (WBC) and glutathione level (Spearman rank correlation coefficient, ρ = 0.45, P = .001). A high DNA index correlated with low glutathione levels (Mann-Whitney test,P = .013). There was no significant relationship between glutathione levels and in vitro drug sensitivity. Patients with glutathione levels above the median had a significantly greater risk of relapse (log-rank test statistic, 5.55; P = .018), and the overall survival rate was significantly reduced (log-rank test statistic, 4.38; P = .04). Multivariate analysis demonstrated that glutathione concentration was of independent prognostic value when assessed in conjunction with age, gender, WBC, and immunophenotype. The association of elevated blast glutathione levels with an increased risk of relapse suggests that glutathione-depleting agents may be of therapeutic value in patients who present with a high WBC.
Expression of the c-met proto-oncogene and its ligand, hepatocyte growth factor, in Hodgkin disease
Authors: Teofili Luciana , Di Febo Anna Laura , Pierconti Francesco , Maggiano Nicola , Bendandi Maurizio , Rutella Sergio , Cingolani Antonella , Di Renzo Nicola , Musto Pellegrino , Pileri Stefano , Leone Giuseppe , Larocca Luigi Maria
Published: July 2002

The receptor for hepatocyte growth factor (HGF) is a transmembrane tyrosine kinase that is encoded by the proto-oncogene c-met. Recently, c-MET was detected in Reed-Sternberg (RS) cells from Epstein-Barr virus–positive (EBV+) Hodgkin disease (HD). The c-MET, EBER-1, and LMP-1 expression in 45 lymph node biopsies and 12 bone marrow biopsies obtained from patients with HD was analyzed. In addition, HGF levels in serum samples from 80 healthy individuals and 135 HD patients in different phases of disease. In all 45 lymph node and 12 bone marrow samples examined, RS cells expressed c-MET but not HGF+. These results were independent of the EBV infection. Interestingly, several HGF+ dendritic-reticulum cells were found scattered around c-MET+ RS cells. The mean ± SEM serum HGF levels in HD patients at diagnosis and at the time of relapse were 1403 ± 91 (95% confidence interval [CI], 1221-1585) and 1497 ± 242 pg/mL (95% CI, 977-2017), respectively. HGF values were significantly higher than those of healthy individuals (665 ± 28 pg/mL; 95% CI, 600-721; and P < .001 for both groups of patients) and of HD patients in remission (616 ± 49 pg/mL; 95% CI, 517-714; andP < .001 for both groups of patients). A significant correlation was found between serum HGF levels and B symptoms at diagnosis (P = .014). In conclusion, this study indicates that HGF and c-MET constitute an additional signaling pathway between RS cells and the reactive cellular background, thereby affecting adhesion, proliferation, and survival of RS cells. Furthermore, the serum concentration of HGF in HD patients may be a useful tool in monitoring the status of disease.
Alboaggregin A activates platelets by a mechanism involving glycoprotein VI as well as glycoprotein Ib
Authors: Dörmann Dagmar , Clemetson Jeannine M. , Navdaev Alexei , Kehrel Beate E. , Clemetson Kenneth J.
Published: July 2002

The snake venom C-type lectin alboaggregin A (or 50-kd alboaggregin) from Trimeresurus albolabris was previously shown to be a platelet glycoprotein (GP) Ib agonist. However, investigations of the signal transduction induced in platelets showed patterns of tyrosine phosphorylation that were different from those of other GPIb agonists and suggested the presence of an additional receptor. In this study, the binding of biotinylated alboaggregin A to platelet lysates, as well as affinity chromatography evaluations of platelet lysates on an alboaggregin A–coated column, indicated that this other receptor is GPVI. Additional experiments with reagents that inhibit either GPIb or GPVI specifically supported this finding. These experiments also showed that both GPIb and GPVI have a role in the combined signaling and that the overall direction this takes can be influenced by inhibitors of one or the other receptor pathway.