bluuebunny/crossref_metadata_2025_split huggingface dataset:
Allozyme variation and geographic differentiation in the Chilean leptodactylid frog Batrachyla taeniata (Girard, 1854)
Authors: Brieva Lila , Formas J. Ramón 
Published: July 2002

AbstractElectrophoretic variation in proteins encoded by 15 loci was analyzed in nine populations of the Chilean leptodactylid frog Batrachyla taeniata. The overall proportion of polymorphic loci was estimated to be 16.2% and the average number of alleles per locus, 1.18. The mean observed and expected heterozygosities for the populations were 0.9% and 5.9%, respectively. The average Rogers genetic distance among pairs of populations was 0.105. F statistics analysis showed high levels of genetic subdivision (Fst = 0.450). An isolation-by-distance test indicated significant correlation between genetic and geographical distance. Resumen. Se analizó la variabilidad electroforética de proteínas codificadas por 15 loci en nueve poblaciones de la rana leptodactílida chilena Batrachyla taeniata. La proporción general de loci polimórficos se estimó en 16,2% y el número promedio de alelos por locus en 1,18. Las heterocigosidades observadas y esperadas promedio fueron 0,9% y 5,9% respectivamente. El promedio de la distancia de Rogers entre pares de poblaciones fue 0,105. El análisis estadístico de F mostró altos niveles de subdivisión genética (Fst = 0,450). El análisis del aislamiento por distancia indicó una correlación significativa entre la distancia genética y la distancia geográfica.
Movement of Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) in tracheal system of adult Monochamus alternatus (Coleoptera: Cerambycidae)
Authors: Aikawa Takuya , Togashi Katsumi 
Published: July 2002

Abstract
To clarify the movement of Bursaphelenchus xylophilus in the tracheal system
of adult Monochamus alternatus, 49 adult beetles were dissected 0, 15, 30,
45 or 60 days after emergence and the nematodes heading inwards to the
distal end and outwards to spiracles in tracheae were counted. In adult
beetles just after emergence, the majority of nematodes headed inwards. The
proportion of tracheae with nematodes heading outwards was significantly
higher for beetles aged 15, 30 or 45 days than for newly-emerged beetles.
The proportion of nematodes pointing outwards tended to increase with beetle
age and was significantly greater in 45-day old beetles than in newly
emerged ones. A comparison of prediction with observation suggests that the
nematodes move forwards in the tracheal system from spiracles and exit from
spiracles after turning round in the tracheae. Le déplacement de
Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) dans le système
trachéen des adultes de Monochamus alternatus (Coleoptera: Cerambycidae) -
Pour mieux comprendre le déplacement de Bursaphelenchus xylophilus dans le
système trachéen de Monochamus alternatus 49 insectes ont été disséqués 0,
15, 30, 45 ou 60 jours après l'émergence et les nématodes se dirigeant dans
les trachées vers l'intérieur - partie distale - et vers l'extérieur -
stigmates - ont été comptés. Chez les insectes adultes, immédiatement après
l'émergence la majorité des nématodes se dirigent vers l'intérieur. La
proportion de trachées contenant des nématodes se dirigeant vers l'extérieur
est significativement plus élevée chez les insectes âgés de 15, 30 ou 45
jours que chez ceux ayant émergé depuis peu. La proportion de nématodes se
dirigeant vers l'avant a tendance à croître avec l'âge de l'insecte: elle
est en effet significativement plus élevée chez les insectes âgés de 45
jours que chez ceux dont l'émergence est récente. La comparaison entre
projection et observations suggère que les nématodes progressent dans le
système trachéen à partir des stigmates et sortent par ces derniers après
s'être retournés dans la trachée.
Développement des populations de Meloidogyne javanica et de Scutellonema cavenessi dans les systèmes de culture maraîchère au Sénégal
Authors: Diop Mamadou Thiam , Ndiaye Saliou , Mounport Danamou , Mateille Thierry 
Published: July 2002

Abstract
L'évolution des populations de Meloidogyne javanica et de Scutellonema
cavenessi a été suivie au cours de cinq cycles culturaux alternant des
plantes sensibles (tomate, niébé ou plantes adventices) ou non sensibles
(arachide et mil) à Meloidogyne spp. Alors que les cultures non sensibles ne
permettent effectivement pas la multiplication de M. javanica, toutes les
cultures sont sensibles à S. cavenessi. L'opportunité de méthodes de lutte
culturale à l'aide de plantes résistantes à Meloidogyne spp. dans des
systèmes de cultures susceptibles de modifier la composition des peuplements
nématologiques est discutée. Development of Meloidogyne javanica and
Scutellonema cavenessi populations in vegetable crop systems in Senegal -
Populations of Meloidogyne javanica and Scutellonema cavenessi were analysed
during five cycles alternating crops susceptible (tomato, cowpea or weeds)
or not susceptible (groundnut and millet) to Meloidogyne spp. Even though
the non-susceptible crops did not effectively allow the multiplication of M.
javanica, all the crops were susceptible to S. cavenessi. The potential of
cultural control methods with plants resistant to Meloidogyne spp. in
agrosystems including crops which can modify the nematode communities is
discussed.
Radopholus nativus (Nematoda: Pratylenchidae), a potential economic pest of wheat in Western Australia
Authors: Kelly Sean , Riley Ian 
Published: July 2002

AbstractLarge population densities (more than 100 000 per g dry weight of roots) of Radopholus nativus apparently caused economic damage to wheat near Wyalkatchem, Western Australia. Plants in large areas of poor growth were colonised by R. nativus, whereas in areas of better growth Pratylenchus neglectus occurred at lower population densities. The boundary between the areas was distinct. In the same year (1998), a further nine wheat samples were found to be infested with R. nativus through examination of 300 diagnostic samples submitted by Western Australian growers. Mixed Radopholus/Pratylenchus populations occurred in six of those samples. Populations of R. nativus were widely dispersed throughout the cropping areas of the State. It is concluded that R. nativus has the potential under certain conditions and/or crop rotations to reach high population density and cause economic loss.
Plant parasitic nematodes from a forest tree nursery in southern Spain with some notes about the influence of soil storage on the quantitative recovery of Meloidogyne arenaria
Authors: Talavera Miguel , Magunacelaya Juan Carlos , Tobar Antonio 
Published: July 2002

Abstract
A nematological survey was carried out in a forest tree nursery in Andujar,
southern Spain. Meloidogyne arenaria was found in soil and roots samples
from Acacia sp., Biota sp., Juglans regia, Pinus spp., Salix babilonica and
Sophora japonica. Pratylenchus vulnus was found in Acacia sp., Cupressus
macrocarpa, Juglans regia, Ligustrum japonica, Morus sp., Pinus spp.,
Populus sp., Salix babilonica and Ulmus pumila. Helicotylenchus sp.,
Xiphinema americanum and Tylenchorhynchus sp. were found in all the plant
species planted in the nursery. Paratylenchus sp., Criconemella sp. and
Zygotylenchus guevarai host ranges are also given. The influence of soil
storage on the recovery of M. arenaria was studied. At storage temperatures
similar to those of the nursery (10-15°C), densities of M. arenaria in soil
increased until the sixth week after sampling and were then maintained until
the thirteenth week of storage. Incubation temperatures below 16°C during
the migration of nematodes through a cottonwool filter, reduced the number
of M. arenaria juveniles recovered after 15 h, but increasing migration time
up to 39 h could counterbalance this reduction. Pflanzenparasitare Nematoden
aus einer sudspanischen Forstbaumschulemit einigen Bemerkungen uber den
Einfluss der Probenlagerung auf den quantitativen Nachweis von Meloidogyne
arenaria - In einer Forstbaumschule in Andujar, Sudspanien, wurde eine
nematologische Untersuchung durchgefuhrt. Meloidogyne arenaria wurde in
Boden- und Wurzelproben von Acacia sp., Biota sp., Juglans regia, Pinus
spp., Salix babilonica und Sophora japonica gefunden. Pratylenchus vulnus
konnte an Acacia sp., Cupressus macrocarpa, Juglans regia, Ligustrum
japonica, Morus sp., Pinus spp., Populus sp., Salix babilonica und Ulmus
pumila nachgewiesen werden. Helicotylenchus sp., Xiphinema americanum und
Tylenchorhynchus sp. wurden an allen Pflanzenarten gefunden, die in der
Baumschule angebaut wurden. Ferner werden die Wirtspflanzen von
Paratylenchus sp., Criconemella sp. und Zygotylenchus guevarai genannt. Dann
wurde auch der Einfluss der Probelagerung auf den Nachweis von M. arenaria
untersucht. Bei Lagerungstemperaturen von 10-15°C, die ahnlich waren wie die
in der Baumschule, nahmen die Dichten von M. arenaria bis zur sechsten Woche
nach der Probenahme zu und hielten sich dann bis zur 13. Woche der Lagerung.
Temperaturen unter 16°C wahrend der Wanderung durch ein Baumwollwattefilter
verminderten die Anzahl der nach 15h wiedergefundenen Juvenilen, doch konnte
eine Verlangerung der Wanderzeit auf 39h diese Verminderung ausgleichen.
Variations in the chemistry of smectites from the Calatayud Basin (NE Spain)
Authors: Mayayo M. J. , Bauluz B. , Gonzalez Lopez J. M. 
Published: July 2002

AbstractSmectites of sedimentary series from a playa lake system from Calatayud Basin have been studied by XRD and TEM chemical microanalyses. Clay particle microanalyses show complete continuity between dioctahedral aluminous and trioctahedral magnesian smectites. Aluminous smectites have been classified as montmorillonites and ferribeidellites, both with compositional variability. They represent detrital phases resulting from weathering in the source area. Compositionally-intermediate smectites (beidellite-saponite and montmorillonite-stevensite) seem to correspond to weighted mean compositions of di- and trioctahedral phases stacked together in the same particle. They represent intermediate transitional stages from detrital to authigenic smectites in more distal basin facies. Trioctahedral smectites, although called saponites and stevensites, are actually random mixed-layer kerolite-Mg-smectite with a high percentage of expandable layers. They represent authigenic clays formed from solutions with high pH and Mg content as a result of evaporative concentration. The variability in composition of smectites, both within the same sample and amongst different samples, is a possible consequence of the heterogeneity in the local chemical environment, and so, equilibrium may be only reached locally in a large variety of microsystems.
Hydrothermal formation of kaolinite from various metakaolins
Authors: Fialips C. - I . , Petit S. , Decarreau A. 
Published: July 2002

AbstractMetakaolins formed by total dehydroxylation of kaolinite, dickite and nacrite were hydrothermally treated at 240°C, for 2, 21 or 182 days, at initial pH = 5– 6 or 1. Kaolinite was the only mineral of the kaolin subgroup crystallized in these treatments. Kaolinite is less ordered for pH = 4– 6 than for pH = 1. This can be attributed to the influence of specific chemical, morphological, and/or crystalline properties of the metakaolins. Two different processes of kaolinite formation and crystal growth must be involved depending on the pH and metakaolin. The first process implies the dissolution of the metakaolin and crystallization of thin prismatic or dendritic kaolinite particles which curl, probably due to surface tension. The second process implies the rapid formation of small pseudohexagonal kaolinite particles which would aggregate and coalesce to form bigger particles.
Clay minerals in the agricultural surface soils in the Central United States
Authors: Velde B. 
Published: July 2002

AbstractA survey of the clay fraction at the surface of 86 loam and silt loam agricultural soils from the Central United States was undertaken to observe the possible influences of climate and parent material (dominantly phyllosilicates in this study) on the clay mineralogy of the upper portions of the soils, for the most part in Mollisol–Alfisol order soils.Decomposed X-ray diffraction spectra show that the most abundant clay minerals are two disordered illite-smectite (I-S) minerals, one with ∼50% smectite layers and another, less abundant, disordered I-S phase with 20% smectite. These minerals usually co-exist in the same samples. The charge site in both of these I-S minerals is both beidellitic and montmorillonitic in the expanding layers. A relatively large proportion of these smectite layers (up to 20%) are of high charge.There seems to be a convergence in mineralogy towards mixed-layer phases formed under a range of mid-Continent climates from a range of phyllosilicate parent materials.
Mineral fractionation and pre- and post-emplacement processes in the uppermost part of the Shiant Isles Main Sill
Authors: Henderson C. M. B. , Gibb F. G. F. , Foland K. A. 
Published: July 2002

AbstractReinvestigation of the top 25 m of the 165 m thick Shiant Isles Main Sill requires reinterpretation of its internal structure, especially of the last unit emplaced – the granular olivine picro-dolerite. New mineral analyses allow re-assessment of the magmatic processes involved in the intrusion and differentiation of this classic multiple sill. C-shaped vertical mineral composition profiles, which occur in olivine-rich, alkaline basaltic sills, reflect reaction between phenocrysts and variable composition liquids. A case is made for vertical migration of interstitial liquids within and across the boundaries of intrusive units, for the mixing of such liquids from adjacent units, and for their influence on mineral chemistry on both sides of the interface.
An explanation for the origin of hemihedrism in wulfenite: the single-crystal structures ofI41/a andItungstenian wulfenites
Authors: Hibbs D. E. , Jury C. M. , Leverett P. , Plimer I. R. , Williams P. A. 
Published: July 2002

AbstractThe single-crystal X-ray structure of tungstenian wulfenite-I41/acontaining 10 mol.% WO3from the San Francisco mine, Sonora, Mexico, space groupI41/a,a= 5.436(2),c= 12.068(8)Å andZ= 4, has been refined toR= 0.052. The Mo and W are disordered over special position 4a(0,0,0) in the lattice. Tungstenian wulfenite-I4̄ (‘chillagite’) from the Christmas Gift mine, Chillagoe, Queensland, Australia (Museum of Victoria specimen M16934), crystallizes in the closely related tetragonal space groupI4̄, witha= 5.441(1),c= 12.068(6) Å andZ= 4. The structure was refined toR= 0.038. Refined site occupancy factors show that Mo and W are not distributed equally over the two crystallographically independent Mo/W positions, being 0.136(2) for Mo and 0.114(2) for W in special position 2a(0,0,0) and 0.184(2) for Mo and 0.066(2) for W in special position 2c(0,Ý,Ü). These give a composition corresponding to wulfenite64stolzite36, in agreement with analytical data. The Mo/W distributions in the unit cell provide one explanation for the origin of hemihedrism in the wulfenite-stolzite series.
Al-free gyrolite from the Lizard, Cornwall, England
Authors: Elton N. J. , Hooper J. J. , Holyer V. A. D. 
Published: July 2002

AbstractGyrolite containing no detectable Al (<0.04 wt.%) has been found as aggregates of platey crystals to 6 mm at Dean Quarry, the Lizard, Cornwall. The gyrolite occurs embedded in calcite which fills a fracture vein in gabbro. Paragenetic evidence is inconclusive, but suggests that gyrolite formed relatively early, after prehnite, and possibly around the same time as analcime and natrolite.
Polymorphic transformations between olivine, wadsleyite and ringwoodite: mechanisms of intracrystalline nucleation and the role of elastic strain
Authors: Kerschhofer Ljuba , Dupas Catherine , Liu Ming , Sharp Thomas G. , Durham William B. , Rubie David C. 
Published: July 2002

AbstractKinetic models and rate equations for polymorphic reconstructive phase transformations in polycrystalline aggregates are usually based on the assumptions that (a) the product phase nucleates on grain boundaries in the reactant phase and (b) growth rates of the product phase remain constant with time at fixed P-T. Recent observations of experimentally-induced transformations between (Mg,Fe)2SiO4 olivine (α) and its high pressure polymorphs, wadsleyite (β) and ringwoodite (γ), demonstrate that both these assumptions can be invalid, thus complicating the extrapolation of experimental kinetic data. Incoherent grain boundary nucleation appears to have dominated in most previous experimental studies of the α–β–γ transformations because of the use of starting materials with small (<10–20 µm) grain sizes. In contrast, when large (0.6 mm) olivine single crystals are reacted, intracrystalline nucleation of both β and γ becomes the dominant mechanism, particularly when the P-T conditions significantly overstep the equilibrium boundary. At pressures of 18–20 GPa intracrystalline nucleation involves (i) the formation of stacking faults in the olivine, (ii) coherent nucleation of γ-lamellae on these faults and (iii) nucleation of β on γ. In other experiments, intracrystalline nucleation is also observed during the β-γ transformation. In this case coherent nucleation of γ appears to occur at the intersections of dislocations with (010) stacking faults in β, which suggests that the nucleation rate is stress dependent. Reaction rims of β/γ form at the margins of the olivine single crystals by grain boundary nucleation. Measurements of growth distance as a function of time indicate that the growth rate of these rims decreases towards zero as transformation progresses. The growth rate slows because of the decrease in the magnitude of the Gibbs free energy (stored elastic strain energy) that develops as a consequence of the large volume change of transformation. On a longer time scale, growth kinetics may be controlled by viscoelastic relaxation.
A multi-method analysis of Si-, S- and REE-rich apatite from a new find
of kalsilite-bearing leucitite (Abruzzi, Italy)
Authors: Comodi P. , Liu Y. , Stoppa F. , Woolley A.R. 
Published: July 2002

Abstract
The crystal chemistry characteristics of a hydroxyl-fluor apatite from a
recently discovered kalsilite-bearing leucitite from Abruzzi, Italy, were
investigated by electron microprobe, single crystal X-ray diffraction, IR, Raman
and micro-Raman spectroscopy. The apatite has exceptionally high S and relatively
high Si, Sr and LREE, whereas the
HREE content is negligible. The IR spectra confirm
the presence of OH calculated from formula difference. A high positive correlation
between Ca-site Substitution Index (CSI = 100(10-Ca)/Ca) and Tetrahedral
Substitution Index (TSI = 100 (Si+C+S)/P atom/a.p.f.u.) and a systematic parallel
increase in REE, S and Si indicate two substitution
mechanisms, i.e. REE3+ +
Si4+ = Ca2+ +
P5+ and Si4+ +
S6+ = 2 P5+. Site occupancy data and
bond lengths, determined from structural refinements on selected samples,
demonstrate that LREE and Sr show a marked preference
for the Ca2 site, even though in the LREE-rich samples
a partial substitution of LREE for Ca in the Cal site
was observed.
Tetrahedral distances (from 1.535 to 1.541 Å.) reflect the substitution of
Si4+ and S6+ for
P5+, which is also confirmed by vibrational spectra. As
(SiO4)4− and
(SO4)2− substitute for
(PO4)3−, the relative intensity of
v1 Raman bands of
(SO4)2− (at 1007
cm−1) and
(SiO4)4− (at 865
cm−1) increase systematically, while that of phosphate
decreases and the five components of phosphate v3 modes
disappear. Moreover, the (PO4)3− Raman
peak broadening is linearly correlated with the Si and S concentrations.
Apatite crystals are sometimes zoned with compositions varying from
SiO2 = 1.15–2.07 wt.%,
Σ(LREE2O3)
= 0.56–1.08 wt.% and SrO = 0.58–1.02 wt.% in the core to 3.98–5.03, 4.14–6.73 and
1.97–2.17, respectively, in the rim. A sharp, strong enrichment in Sr and
LREE in the rim indicate that the apatite suddenly
became an acceptor of these elements in the late stages of
crystallization.
Shwachman-Diamond syndrome marrow cells show abnormally increased apoptosis mediated through the Fas pathway
Authors: Dror Yigal , Freedman Melvin H. 
Published: July 2002

AbstractShwachman-Diamond syndrome (SDS) is an inherited bone marrow disorder with varying cytopenias and a strong predilection to myelodysplastic syndrome (MDS) and acute myeloid leukemia. Previously, it was found that the percentage of CD34+ cells in bone marrow and the in vitro colony formation from CD34+ cells of patients with SDS were markedly reduced. For these reasons, and because apoptosis is central in the pathogenesis of bone marrow dysfunction in MDS, this study was initiated to delineate the role of apoptosis in the pathogenesis of the marrow failure. Eleven children with SDS were studied. Compared to normal controls, patients' marrow mononuclear cells plated in clonogenic cultures showed a significantly higher tendency to undergo apoptosis. The defect in SDS was found in patients with and without MDS. Patients showed a more prominent decrease in colony formation and increased apoptosis after preincubation with activating anti-Fas antibody. Fas expression on marrow cells from patients was significantly higher than from normal controls. The difference between patients and controls for Fas expression was also significant for the following cell fraction subpopulations: CD34−/CD38−, CD34−/CD38+, and CD34+. In conclusion, SDS hematopoietic progenitors are intrinsically flawed and have faulty proliferative properties and increased apoptosis. Bone marrow failure in SDS appears mediated by increased apoptosis as the central pathogenetic mechanism. This increased propensity for apoptosis is linked to increased expression of the Fas antigen and to hyperactivation of the Fas signaling pathway.
Defective octamer-dependent transcription is responsible for silenced immunoglobulin transcription in Reed-Sternberg cells
Authors: Theil Jan , Laumen Helmut , Marafioti Theresa , Hummel Michael , Lenz Georg , Wirth Thomas , Stein Harald 
Published: July 2002

AbstractThe absence of immunoglobulin (Ig) expression in B-cell–derived Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin disease (cHD) was initially suggested to be caused by crippling mutations in the Ig promoter or coding region. More recent investigations have, however, challenged this concept. This study addressed the role of mutations in the Ig promoter region in HRS cells. Nine cases of cHD and 3 B-cell–derived HD lines were analyzed for mutations in the TATA box and octamer motif of the Ig promoter. Mutations in the octamer motif were found in only 1 of the 9 cases and in 1 of the 3 HD cell lines (L1236). Furthermore, in all cases either a complete lack or strong reduction in the expression of the Oct2 transcription factor and the BOB.1/OBF.1 coactivator were found. The relevance of the rare promoter mutations was investigated by assaying the activity of Ig promoter reporter constructs transfected into the HD cell line L1236, which harbors a mutated octamer motif. These Ig reporter constructs were completely inactive in L1236 cells; however, their activity could be reconstituted by the cotransfection of a BOB.1/OBF.1 expression vector. The additional transfection with an Oct2 expression vector did not further enhance the Ig promoter activity. The conclusions drawn from these results are that crippling mutations in the Ig promoter and coding region are not the sole cause for the lack of Ig expression in HRS cells and that defects in the transcription machinery such as absence of BOB.1/OBF.1 are more important for this phenomenon.