bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fire frequency and time‐since‐fire effects on the open‐forest and woodland flora of Girraween National Park, south‐east Queensland, Australia
Authors: Watson Penny , Wardell‐Johnson Grant 
Published: April 2004

Abstract  The effects of recent fire frequency and time‐since‐fire on plant community composition and species abundance in open‐forest and woodland vegetation in Girraween National Park, south‐east Queensland, Australia, were examined. Cover‐abundance data were collected for shrub and vine species in at least 10 400‐m2 plots in each of four study areas. Study areas were within one community type and had burnt most recently either 4 or 9 years previously. Variations in fire frequency allowed us to compare areas that had burnt at least three times in the previous 25 years with less frequently burnt areas, and also woodlands that had experienced a 28‐year interfire interval with more frequently burnt areas. Although species richness did not differ significantly with either time‐since‐fire or fire frequency, both these factors affected community composition, fire frequency being the more powerful. Moisture availability also influenced floristics. Of the 67 species found in five or more plots, six were significantly associated with time‐since‐fire, whereas 11 showed a significant difference between more and less frequently burnt plots in each of the two fire‐frequency variables. Most species, however, did not vary in cover‐abundance with the fire regime parameters examined. Even those species that showed a marked drop in cover‐abundance when exposed to a particular fire regime generally maintained some presence in the community. Five species with the capacity to resprout after fire were considered potentially at risk of local extinction under regimes of frequent fire, whereas two species were relatively uncommon in long‐unburnt areas. Variable fire regimes, which include interfire intervals of at least 15 years, could be necessary for the continuity of all species in the community.
Thermal convection in faulted extensional sedimentary basins: theoretical results from finite‐element modeling
Authors: Simms M. A. , Garven G. 
Published: April 2004

AbstractThermal convection has the potential to be a significant and widespread mechanism of fluid flow, mass transport, and heat transport in rift and other extensional basins. Based on numerical simulation results, large‐scale convection can occur on the scale of the basin thickness, depending on the Rayleigh number for the basin. Our analysis indicates that for syn‐rift and early post‐rift settings with a basin thickness of 5 km, thermal convection can occur for basal heat flows ranging from 80 to 150 mW m−2, when the vertical hydraulic conductivity is on the order of 1.5 m year−1 and lower. The convection cells have characteristic wavelengths and flow patterns depending on the thermal and hydraulic boundary conditions. Steeply dipping extensional faults can provide pathways for vertical fluid flow across large thicknesses of basin sediments and can modify the dynamics of thermal convection. The presence of faults perturbs the thermal convective flow pattern and can constrain the size and locations of convection cells. Depending on the spacing of the faults and the hydraulic properties of the faults and basin sediments, the convection cells can be spatially organized to align with adjacent faults. A fault‐bounded cell occurs when one convection cell is constrained to occupy a fault block so that the up‐flow zone converges into one fault zone and the down‐flow zone is centred on the adjacent fault. A fault‐bounded cell pair occurs when two convection cells occupy a fault block with the up‐flow zone located between the faults and the down‐flow zones centred on the adjacent faults or with the reverse pattern of flow. Fault‐bounded cells and cell pairs can be referred to collectively as fault‐bounded convective flow. The flow paths in fault‐bounded convective flow can be lengthened significantly with respect to those of convection cells unperturbed by the presence of faults. The cell pattern and sense of circulation depend on the fault spacing, sediment and fault permeabilities, lithologic heterogeneity, and the basal heat flow. The presence of fault zones also extends the range of conditions for which thermal convection can occur to basin settings with Rayleigh numbers below the critical value for large‐scale convection to occur in a basin without faults.The widespread potential for the occurrence of thermal convection suggests that it may play a role in controlling geological processes in rift basins including the acquisition and deposition of metals by basin fluids, the distribution of diagenetic processes, the temperature field and heat flow, petroleum generation and migration, and the geochemical evolution of basin fluids. Fault‐bounded cells and cell pairs can focus mass and heat transport from longer flow paths into fault zones, and their discharge zones are a particularly favourable setting for the formation of sediment‐hosted ore deposits near the sea floor.
Hydrothermal control on organic matter alteration and illite precipitation, Mt Isa Basin, Australia
Authors: Uysal I. T. , Glikson M. , Golding S. D. , Southgate P. N. 
Published: April 2004

AbstractAbundant illite precipitation in Proterozoic rocks from Northern Lawn Hill Platform, Mt Isa Basin, Australia, occurred in organic matter‐rich black shales rather than in sandstones, siltstones and organic matter‐poor shales. Sandstones and siltstones acted as impermeable rocks, as early diagenetic quartz and carbonate minerals reduced the porosity–permeability. Scanning and transmission electron microscopy (SEM and TEM) studies indicate a relation between creation of microporosity–permeability and organic matter alteration, suitable for subsequent mineral precipitation. K–Ar data indicate that organic matter alteration and the subsequent illite precipitation within the organic matter occurred during the regional hydrothermal event at 1172 ± 50 (2σ) Ma. Hot circulating fluids are considered to be responsible for organic matter alteration, migration and removal of volatile hydrocarbon, and consequently porosity–permeability creation. Those rocks lacking sufficient porosity–permeability, such as sandstones, siltstones and organic matter poor shales, may not have been affected by fluid movement. In hydrothermal systems, shales and mudstones may not be impermeable as usually assumed because of hydrocarbons being rapidly removed by fluid, even with relatively low total organic carbon.
Salinity structure of the central North Slope foreland basin, Alaska, USA: implications for pathways of past and present topographically driven regional fluid flow
Authors: Hanor J. S. , Nunn J. A. , Lee Y. 
Published: April 2004

AbstractPrevious studies of the areal variation in heat flow in the National Petroleum Reserve Alaska (NPRA) support the existence of an active topographically driven regional fluid flow regime in this central part of the North Slope foreland basin. Drilling records and wireline logs for over 30 wells drilled in the NPRA provide additional field information, which can be used to further constrain interpretation of the pattern of regional flow of basinal waters within the NPRA. Hydraulic heads estimated from drilling mud weights show that ground water flow occurs generally from south to north, but with divergence to the north‐east and north‐west away from the central part of the NPRA towards coastal areas of elevated shallow heat flow. Salinities calculated from SP logs range from less than 1 g L−1, to marine values of 35 g L−1, to hypersaline values of over 150 g L−1. The entire upper sedimentary section to a depth of 2 km or more in the eastern part of the NPRA has been preferentially flushed with meteoric water through an area corresponding to the sandiest portion of the Nanushuk group. Deeper areas of low salinity occur within the Sadlerochit and Lisburne sections. The pattern of regional flow in the east is complicated, however, by the presence of a large mass of hypersaline water at depth. It is not known whether these brines are being displaced laterally and upward towards the discharge end of the basin or whether fresher waters are simply riding up over the top. Deep, hypersaline waters also occur in fault slices in the Brooks Range and have survived meteoric flushing. The brines were probably formed at the time of deposition of the Lisburne carbonates. The fluid flow regime to the west is different. Low‐salinity waters may be flowing northward underneath this section through the Ellesmerian section and discharging upward nearer the coast. However, sparse well log control severely limits what can be deduced about the details of flow paths in the central and western parts of the NPRA.
Metamorphic and basin fluids in quartz–carbonate–sulphide veins in the SW Scottish Highlands: a stable isotope and fluid inclusion study
Authors: Anderson R. , Graham C. M. , Boyce A. J. , Fallick A. E. 
Published: April 2004

AbstractMetalliferous (Fe–Cu–Pb–Zn) quartz–carbonate–sulphide veins cut greenschist to epidote–amphibolite facies metamorphic rocks of the Dalradian, SW Scottish Highlands, with NE–SW to NW–SE trends, approximately parallel or perpendicular to regional structures. Early quartz was followed by pyrite, chalcopyrite, sphalerite, galena, barite, late dolomite–ankerite and clays. Both quartz–sulphide and carbonate vein mineralisation is associated with brecciation, indicating rapid release of fluid overpressure and hydraulic fracturing.Two distinct mineralising fluids were identified from fluid inclusion and stable isotope studies. High temperature (>350°C) quartz‐precipitating fluids were moderately saline (4.0–12.7 wt.% NaCl equivalent) with low (approximately 0.05). Quartz δ18O (+11.7 to +16.5‰) and sulphide δ34S (−13.6 to −1.1‰) indicate isotopic equilibrium with host metasediments (rock buffering) and a local metasedimentary source of sulphur. Later, low‐temperature (TH = 120–200°C) fluids, probably associated with secondary carbonate, barite and clay formation, were also moderately saline (3.8–9.1 wt.% NaCl equivalent), but were strongly enriched in 18O relative to host Dalradian lithologies, as indicated by secondary dolomite–ankerite (δ18O = +17.0 to +29.0‰, δ13C = −1.0 to −3.0‰). Compositions of carbonate–forming fluids were externally buffered.The veins record the fluid–rock interaction history of metamorphic host rocks during cooling, uplift and later extension. Early vein quartz precipitated under retrograde greenschist facies conditions from fluids probably derived by syn‐metamorphic dehydration of deeper, higher‐grade rocks during uplift and cooling of the Caledonian metamorphic complex. Veins are similar to those of mesothermal veins in younger Phanerozoic metamorphic belts, but are rare in the Scottish Dalradian. Early quartz veins were reactivated by deep penetration of low‐temperature basin fluids that precipitated carbonate and clays in veins and adjacent Dalradian metasediments throughout the SW Highlands, probably in the Permo‐Carboniferous. This event is consistent with paragenetically ambiguous barite with δ34S characteristic of late Palaeozoic basinal brines.
Emanuel Miller lecture: Confusions and controversies about Asperger syndrome
Authors: Frith Uta 
Published: March 2004

Background: Hans Asperger drew attention to individuals who show the core symptoms of autism in the presence of high verbal intelligence.Methods: A review of the literature explores current issues concerning the diagnosis and nature of Asperger syndrome.Results: The behavioural and neurophysiological evidence to date suggests that Asperger syndrome is a variant of autism typically occurring in high‐functioning individuals, and not a separate disorder. One of the problems of diagnosis is that the typical impairment of social communication may be difficult to identify in early childhood, and can be camouflaged in adulthood by compensatory learning. The range and nature of the social impairments in Asperger syndrome are still in need of investigation, but appear to be less severe than in autism. Experimental evidence suggests that individuals with Asperger syndrome may lack an intuitive theory of mind (mentalising), but may be able to acquire an explicit theory of mind. Brain imaging studies pinpoint a network that links medial prefrontal and temporal cortex as the neural substrate of intuitive mentalising. This network shows reduced activation and poor connectivity in Asperger syndrome. While some individuals with Asperger syndrome have written eloquently about their lives, their ability to talk about their own emotions appears to be impaired (alexithymia). This impairment may be linked to depression and anxiety, which is common in adulthood. Little is as yet known about the often considerable cognitive strengths in Asperger syndrome, or about the difficulties observed in higher‐level executive skills.Conclusions: Studies are needed that define the developmental course of the disorder and the nature of the strengths and weaknesses in both social and non‐social domains. This requires more sensitive assessment instruments than are currently available. Questions about the prevalence of Asperger syndrome, about associated and secondary features, and about optimal education and management, urgently call for such studies.
Emotion recognition/understanding ability in hearing or vision‐impaired children: do sounds, sights, or words make the difference?
Authors: Dyck Murray J. , Farrugia Charles , Shochet Ian M. , Holmes‐Brown Martez 
Published: March 2004

Background:  This study was designed to assess whether children with a sensory disability have consistent delays in acquiring emotion recognition and emotion understanding abilities.Method:  Younger (6–11 years) and older (12–18 years) hearing‐impaired children (HI; n = 49), vision‐impaired children (VI; n = 42), and children with no sensory impairment (NSI; n = 72) were assessed with the Emotion Recognition Scales (ERS), which include two tests of the ability to recognize vocal expressions of emotion, two tests of the ability to recognize facial expressions of emotion, and three tests of emotion understanding.Results:  Results indicate that when compared with age‐peers, HI children and adolescents have significant delays or deficits on all ERS, but VI children and adolescents are delayed only on emotion recognition tasks. When compared with children group‐matched for verbal ability (Wechsler verbal scales), the achievement of HI children on ERS equals or exceeds that of controls; VI children underachieve on an emotion recognition task and overachieve on an emotion vocabulary task compared to verbal ability matched peers.Conclusions:  We conclude that VI children have a specific emotion recognition deficit, but among HI children, performance on emotion recognition and emotion understanding tasks reflects delayed acquisition of a broad range of language‐mediated abilities.
A questionnaire for screening a broad range of DSM‐defined anxiety disorder symptoms in clinically referred children and adolescents
Authors: Muris Peter , Dreessen Laura , Bögels Susan , Weckx Miryam , van Melick Marion 
Published: March 2004

Objective:  To examine the reliability and validity of the 66‐item Screen for Child Anxiety Related Emotional Disorders‐Revised (SCARED‐R), a questionnaire for measuring a broad range of DSM‐defined anxiety disorder symptoms, in a sample of clinically referred youths.Method:  The SCARED‐R was administered to children/adolescents and their parents during the standard intake assessment. SCARED‐R scores were compared against Child Behavior Checklist (CBCL) scores, DSM‐IV axis I classifications, and global assessment of functioning (GAF) ratings.Results:  In this sample of clinically referred youths, the SCARED‐R was reliable in terms of internal consistency and showed reasonable child–parent agreement. Furthermore, SCARED‐R scores correlated significantly with CBCL internalising but not with externalising. Within the group of children with anxiety disorders, SCARED‐R scores were also negatively associated with children's daily functioning as rated on the GAF scale. Finally, SCARED‐R scores had satisfactory discriminant validity (both between anxiety disorders and other problems and within anxiety disorders), and appeared to have reasonable value for predicting specific anxiety disorders.Conclusion:  The SCARED‐R is a valuable addition to the arsenal of questionnaires that are used for the assessment of anxiety in youths.
Social and emotional adjustment of siblings of children with autism
Authors: Pilowsky Tammy , Yirmiya Nurit , Doppelt Osnat , Gross‐Tsur Varda , Shalev Ruth S. 
Published: March 2004

Background:  Social and emotional adjustment of siblings of children with autism was examined, to explore their risk or resilience to effects of genetic liability and environmental factors involved in having a sibling with autism.Method:  Social‐emotional adjustment, behavior problems, socialization skills, and siblings’ relationships were compared among 30 siblings of children with autism, 28 siblings of children with mental retardation of unknown genetic etiology (MR), and 30 siblings of children with developmental language disorders (DLD). Groups were matched by probands’ gender, siblings’ chronological age, gender, IQ, and birth order, and by family size, ethnicity, and parental income, employment, and stress level.Results:  Four siblings of children with autism, three siblings of children with MR, and seven siblings of children with DLD received DSM‐IV diagnoses. Nevertheless, most of the siblings were well adjusted.Conclusions:  The adjustment of siblings of children with autism is in sharp contrast to the severe social and emotional disabilities characteristic of autism, and is noteworthy considering the stress involved in having a sibling with autism.
Serpentinites of the Zermatt‐Saas ophiolite complex and their texture evolution
Authors: Li X.‐P. , Rahn M. , Bucher K. 
Published: April 2004

AbstractThe Zermatt‐Saas serpentinite complex is an integral member of the Penninic ophiolites of the Central Alps and represents the mantle part of the oceanic lithosphere of the Tethys. Metamorphic textures of the serpentinite preserve the complex mineralogical evolution from primary abyssal peridotite through ocean‐floor hydration, subduction‐related high‐pressure overprint, meso‐Alpine greenschist facies metamorphism, and late‐stage hydrothermal alteration. The early ocean floor hydration of the spinel harzburgites is still visible in relic pseudomorphic bastite and locally preserved mesh textures. The primary serpentine minerals were completely replaced by antigorite. The stable assemblage in subduction‐related mylonitic serpentinites is antigorite–olivine–magnetite ± diopside. The mid‐Tertiary greenschist facies overprint is characterized by minor antigorite recrystallization. Textural and mineral composition data of this study prove that the hydrated mineral assemblages remained stable during high‐pressure metamorphism of up to 2.5 GPa and 650 °C. The Zermatt‐Saas serpentinites thus provide a well documented example for the lack of dehydration of a mantle fragment during subduction to 75 km depth.
Zoned (Cretaceous and Cenozoic) garnet and the timing of high grade metamorphism, Southern Alps, New Zealand
Authors: Vry J. K. , Baker J. , Maas R. , Little T. A. , Grapes R. , Dixon M. 
Published: April 2004

AbstractNew (garnet Sm–Nd and Lu–Hf) and existing (Rb–Sr, 40Ar/39Ar, U–Pb and Sm–Nd) ages and data on deformational fabrics and mineral compositions show for the first time that the garnet growth and ductile deformation in the Alpine Schist belt and Southern Alps orogen, New Zealand are diachronous and partly Cenozoic in age. The dominant metamorphic isograds in the Alpine Schist formed during crustal thickening at a previously unsuspected time, at c. 86 Ma, immediately prior to the opening of the Tasman Sea at c. 84–82 Ma. Obvious changes in the textures and compositional zoning patterns of garnet are not always reliable indicators of polymetamorphism, and fabric elements can be highly diachronous.A detailed timing history for the growth of a single garnet is recorded by a Sm–Nd garnet–whole rock age of 97.8 ± 8.1 Ma for the inmost garnet core (zone 1), Lu–Hf ages of 86.2 ± 0.2 Ma and 86.3 ± 0.2 Ma for overgrowth zones 2 and 3, a step‐leach Sm–Nd age of 12 ± 37 Ma for zone 4, and growth of the garnet rim (zone 5) over the Alpine Fault mylonite foliation during the modern phase of oblique collision that began at c. 5–6 Ma.Plate convergence along the New Zealand portion of the Gondwana margin continued after c. 105 Ma, almost certainly culminating in the oblique collision of a large oceanic plateau (Hikurangi Plateau). The metamorphism of the Alpine Schist at c. 86 Ma is evidence of that hit. The mid‐ to late‐Cretaceous extension that is widespread elsewhere in the New Zealand region is attributed to upper plate extension and slab roll‐back. The effects of the collision with the Hikurangi Plateau may have contributed to the changing plate motions in the region leading up to the opening of the Tasman Sea at c. 82 Ma.
Microboudin structures of piemontite along the Sambagawa metamorphic belt, Japan: implications for lateral variation of differential stress during regional metamorphism
Authors: Masuda T. , Shibutani T. , Ochiai T. , Akagi S. , Yamaguchi H. , Kugimiya Y. , Kimura N. , Miyake T. 
Published: April 2004

AbstractEvidence is presented of a lateral variation in differential stress during metamorphism along a regional metamorphic belt on the basis of the proportion of microboudinaged piemontite grains (p) in a quartz matrix in metacherts. It is proposed that p is a practical indicator of relative differential stress. Analysis of 123 metacherts from the 800 km long Sambagawa metamorphic belt, Japan, reveals that p‐values range from < 0.01 to 0.7 in this region. Most samples from Wakayama in the mid‐belt area have p‐values of 0.4–0.6, whereas those from western Shikoku have p‐values of < 0.1. This difference cannot be explained by variations in metamorphic temperature, and is instead attributed to a regional, lateral variation in differential stress during metamorphism.
Vertical extrusion and middle crustal spreading of omphacite granulite: a model of syn‐convergent exhumation (Bohemian Massif, Czech Republic)
Authors: Štípská P. , Schulmann K. , Kröner A. 
Published: April 2004

AbstractThe exhumation of eclogite facies granulites (Omp–Plg–Grt–Qtz–Rt) in the Rychleby Mts, eastern Czech Republic, was a localised process initiated by buckling of crustal layers in a thickened orogenic root. Folding and post‐buckle flattening was followed by the main stage of exhumation that is characterized by vertical ductile extrusion. This process is documented by structural data, and the vertical ascent of rocks from a depth ofc.70 toc.35 km is documented by metamorphic petrology. SHRIMP206Pb/238U and207Pb/206Pb evaporation zircon ages of 342 ± 5 and 341.4 ± 0.7 Ma date peak metamorphic conditions. The next stage of exhumation was associated with sideways flat thrusting associated with lateral viscous spreading of granulites and surrounding rocks over indenting adjacent continental crust at a depth ofc.35–30 km. This stage was associated with syntectonic intrusion of a granodiorite sill at 345–339 Ma, emplaced at a crustal depth ofc.25 km. The time required for cooling of the sill as well as for heating of the country rocks brackets this event to a maximum of 250 000 years. Therefore, similar ages of crystallization for the granodiorite magma and the peak of eclogite facies metamorphism of the granulite suggest a very short period of exhumation, limited by the analytical errors of the dating methods. Our calculations suggest that the initial exhumation rate during vertical extrusion was 3–15 mm yr−1, followed by an exhumation rate of 24–40 mm yr−1during further uplift along a magma‐lubricated shear zone. The extrusion stage of exhumation was associated with a high cooling rate, which decreased during the stage of lateral spreading.