1,700 research outputs found
120 to 0 Ma tectonic evolution of the southwest Pacific and analogous geological evolution of the 600 to 220 Ma Tasman Fold Belt System
We review the tectonic evolution of the SW Pacific east of Australia from ca 120 Ma until the present. A
key factor that developed early in this interval and played a major role in the subsequent geodynamic
history of this region was the calving off from eastern Australia of several elongate microcontinental ribbons,
including the Lord Howe Rise and Norfolk-New Caledonia Ridge. These microcontinental ribbons
were isolated from Australia and from each other during a protracted extension episode from ca 120 to
52 Ma, with oceanic crust accretion occurring from 85 to 52 Ma and producing the Tasman Sea and
the South Loyalty Basin. Generation of these microcontinental ribbons and intervening basins was
assisted by emplacement of a major mantle plume at 100 Ma beneath the southern part of the Lord
Howe Rise, which in turn contributed to rapid and efficient eastward trench rollback. A major change
in Pacific plate motion at ca 55 Ma initiated east-directed subduction along the recently extinct spreading
centre in the South Loyalty Basin, generating boninitic lithosphere along probably more than 1000
km of plate boundary in this region, and growth of the Loyalty-Entrecasteaux arc. Continued subduction
of South Loyalty Basin crust led to the arrival at about 38 Ma of the 70-60 million years old western
volcanic passive margin of the Norfolk Ridge at the trench, and west-directed emplacement of the
New Caledonia ophiolite. Lowermost allochthons of this ophiolite are Maastrichtian and Paleocene rift
tholeiites derived from the underthrusting passive margin. Higher allochthonous sheets include a poorly
exposed boninitic lava slice, which itself was overridden by the massive ultramafic sheets that cover
large parts of New Caledonia and are derived from the colliding forearc of the Loyalty-Entrecasteaux
arc. Post-collisional extensional tectonism exhumed the underthrust passive margin, parts of which have
blueschist and eclogite facies metamorphic assemblages. Following locking of this subduction zone at
38-34 Ma, subduction jumped eastward, to form a new west-dipping subduction zone above which
formed the Vitiaz arc, that contained elements which today are located in the Tongan, Fijian, Vanuatu
and Solomons arcs. Several episodes of arc splitting fragmented the Vitiaz arc and produced first the
South Fiji Basin (31-25 Ma) and later (10 Ma to present) the North Fiji Basin. Collision of the Ontong Java
Plateau, a large igneous province, with the Solomons section of the Vitiaz arc resulted in a reversal of
subduction polarity, and growth of the Vanuatu arc on clockwise-rotating, older Vitiaz arc and South Fiji
Basin crust. Continued rollback of the trench fronting the Tongan arc since 6 Ma has split this arc and
produced the Lau Basin-Havre Trough.
This southwest Pacific style of crustal growth above a rolling-back slab is applied to the 600-220 Ma
tectonic development of the Tasman Fold Belt System in southeastern Australia, and explains key
aspects of the geological evolution of eastern Australia. In particular, collision between a plume-triggered
600 Ma volcanic passive margin and a 510-515 Ma boninitic forearc of an intra-oceanic arc had
the same relative orientation and geological effects as that which produced New Caledonia. A new
subduction system formed probably at least several hundred kilometres east of the collision zone and
produced the Macquarie arc, in which the oldest lavas were erupted ca 480 Ma. Continued slab rollback
induced regional extension and the growth of narrow linear troughs in the Macquarie arc, which
persisted until terminal deformation of this fold belt in the late-Middle to Late Devonian. A similar pattern
of tectonic development generated the New England Fold Belt between the Late Devonian and Late
Triassic. Parts of the New England Fold Belt have been broken from Australia and moved oceanward to
locations in New Zealand, and on the Lord Howe Rise and Norfolk-New Caledonia Rise, during the post-
120 Ma breakup. Given that the Tasman Fold Belt System grew between 600 and 220 Ma by crustal
accretion like the southwest Pacific since 120 Ma, facing the open Pacific Ocean, we question whether
the eastern (Australia-Antarctica) part of the Neoproterozoic Rodinian supercontinent was joined to
Laurentia
Factors influencing growth of the African penguin colony at Boulders, South Africa, 1985–1999
This paper reports on growth of the Boulders colony of African penguins Spheniscus demersus from inception in 1985 to the present. More than 900 pairs now breed there. Growth of the colony slowed in 1995 and 1996and reversed in 1998, coinciding with periods of low abundance of Cape anchovy Engraulis capensis off South Africa. In December 1996, penguins were excluded from a portion of land where they had formerly bred. Theyresponded by increasing the density of their nests in other areas and expanding their area of breeding longshore. These patterns indicate that food and not space are currently controlling colony growth rate. Much of the colonygrowth probably results from immigration of first-time breeders from other colonies. Of immigrants, 70–80% may be from Dyer Island to the south-east, where numbers of penguins have decreased. Boulders also is frequentlyvisited by penguins from other colonies, and by rehabilitated birds
Fluid Particle Accelerations in Fully Developed Turbulence
The motion of fluid particles as they are pushed along erratic trajectories
by fluctuating pressure gradients is fundamental to transport and mixing in
turbulence. It is essential in cloud formation and atmospheric transport,
processes in stirred chemical reactors and combustion systems, and in the
industrial production of nanoparticles. The perspective of particle
trajectories has been used successfully to describe mixing and transport in
turbulence, but issues of fundamental importance remain unresolved. One such
issue is the Heisenberg-Yaglom prediction of fluid particle accelerations,
based on the 1941 scaling theory of Kolmogorov (K41). Here we report
acceleration measurements using a detector adapted from high-energy physics to
track particles in a laboratory water flow at Reynolds numbers up to 63,000. We
find that universal K41 scaling of the acceleration variance is attained at
high Reynolds numbers. Our data show strong intermittency---particles are
observed with accelerations of up to 1,500 times the acceleration of gravity
(40 times the root mean square value). Finally, we find that accelerations
manifest the anisotropy of the large scale flow at all Reynolds numbers
studied.Comment: 7 pages, 4 figure
Docetaxel-carboplatin as first line chemotherapy for epithelial ovarian cancer
A prospective, non-randomized, multicentre, open, dose-finding study of a carboplatin-docetaxel (C-D) combination as first-line chemotherapy in FIGO stage Ic–IV epithelial ovarian cancer. C-D was given 3-weekly for 6 planned cycles, with a 3-day prophylactic dexamethasone regimen (8 mg b.i.d.). 139 eligible patients (Pts) (median age 56 years, range 28–85) were given a total of 750 cycles of chemotherapy in 5 cohorts: Co1, 32 pts, 169 cycles (C at AUC 5 + D 60 mg/m2); Co2, 22 pts, 122 cycles (5 + 75), Co3, 29 pts, 156 cycles (6 + 75), Co4, 27 pts, 146 cycles (7 + 75), Co5, 30 pts, 157 cycles (6 + 85). 110 patients (79%) completed 6 cycles; 17 (12%) stopped due to toxicity. 104 patients (75%) had CTC grade IV neutropenia, and 5 patients (4%) had this associated with fever. There were 2 probable treatment-related deaths. Only 8 patients (6%) experienced grade II–III neurotoxicity (all sensory; no motor > grade I). The maximum tolerated dose was reached in cohorts 4 and 5, and the dose limiting toxicities were myelosuppression and diarrhoea. The overall response rate for the study was 66% (49/74); CA125 response was 75% (70/93). Median progression-free survival was 16.6 months (95% CI 13.3–19.1). Recommended doses are carboplatin AUC 5 (via51 Cr EDTA) or AUC 6 (if calculated) plus docetaxel 75 mg/m2. A randomized trial comparing this regimen with carboplatin-paclitaxel has just completed recruitment. © 2001 Cancer Research Campaign http://www.bjcancer.co
Psychological and physical correlates of musculoskeletal symptoms in male professional divers and offshore workers
Background: Underwater divers are more likely to complain of musculoskeletal symptoms than a control population. Accordingly, we conducted a study to determine whether musculoskeletal symptoms reflected observable physical disorder, to ascertain the relationship between symptoms and measures of mood, memory and executive function and to assess any need for future screening.
Methods: A 10% random sample of responders to a prior postal health questionnaire was examined (151 divers, 120 non-diving offshore workers). Participants underwent physical examination and a neuropsychological test battery for memory and executive function. Participants also completed the Hospital Anxiety and Depression Scale for anxiety (HADSa) and depression (HADSd), and questionnaires for physical health-related quality of life (SF36 PCS), mental health-related quality of life (SF36 MCS), memory (Cognitive Failures Questionnaire (CFQ), Prospective and Retrospective Memory Questionnaire (PRMQ)), executive function (dysexecutive syndrome questionnaire (DEX)), musculoskeletal symptoms (MSS) and general unrelated symptom reporting.
Results: Of participants with moderate/severe musculoskeletal symptoms, 52% had physical signs, and of participants with no symptoms, 73% had no physical signs. There was no difference in the prevalence of signs or symptoms between groups. Musculoskeletal symptoms were associated with lower SF36 PCS for both groups. In divers, musculoskeletal symptoms were associated with higher general unrelated symptom reporting and poorer scoring for HADSa, PRMQ, CFQ and DEX with scores remaining within the normative range. A positive physical examination was associated with general unrelated symptom reporting in divers. There were no differences in neuropsychological test scores attributable to either group or musculoskeletal symptoms.
Conclusions: Musculoskeletal symptoms were associated with physical signs, but this was not a strong effect. Reporting of musculoskeletal symptoms by the divers studied was also associated with a tendency to report symptoms generally or somatisation, and caution should be exercised regarding their interpretation as an indication of physical disease or their use for health screening
Correction to: The novel compound PBT434 prevents iron mediated neurodegeneration and alpha-synuclein toxicity in multiple models of Parkinson's disease.
Following publication of the original article [1], the author identified an error in Fig. 4E. The data and statistics were correct, but the synaptophysin blot was incorrect. The incorrect (Fig. 1) and correct figure (Fig. 2) are shown in this correction article. (Figure presented.)
The novel compound PBT434 prevents iron mediated neurodegeneration and alpha-synuclein toxicity in multiple models of Parkinson's disease
Elevated iron in the SNpc may play a key role in Parkinson's disease (PD) neurodegeneration since drug candidates with high iron affinity rescue PD animal models, and one candidate, deferirpone, has shown efficacy recently in a phase two clinical trial. However, strong iron chelators may perturb essential iron metabolism, and it is not yet known whether the damage associated with iron is mediated by a tightly bound (eg ferritin) or lower-affinity, labile, iron pool. Here we report the preclinical characterization of PBT434, a novel quinazolinone compound bearing a moderate affinity metal-binding motif, which is in development for Parkinsonian conditions. In vitro, PBT434 was far less potent than deferiprone or deferoxamine at lowering cellular iron levels, yet was found to inhibit iron-mediated redox activity and iron-mediated aggregation of α-synuclein, a protein that aggregates in the neuropathology. In vivo, PBT434 did not deplete tissue iron stores in normal rodents, yet prevented loss of substantia nigra pars compacta neurons (SNpc), lowered nigral α-synuclein accumulation, and rescued motor performance in mice exposed to the Parkinsonian toxins 6-OHDA and MPTP, and in a transgenic animal model (hA53T α-synuclein) of PD. These improvements were associated with reduced markers of oxidative damage, and increased levels of ferroportin (an iron exporter) and DJ-1. We conclude that compounds designed to target a pool of pathological iron that is not held in high-affinity complexes in the tissue can maintain the survival of SNpc neurons and could be disease-modifying in PD
The SNAPSHOT study protocol : SNAcking, Physical activity, Self-regulation, and Heart rate Over Time
Peer reviewedPublisher PD
Multi-Locus Variable-Number Tandem Repeat Profiling of Salmonella enterica Serovar Typhi Isolates from Blood Cultures and Gallbladder Specimens from Makassar, South-Sulawesi, Indonesia
Multi-locus variable-number tandem repeat analysis differentiated 297 Salmonella enterica serovar Typhi blood culture isolates from Makassar in 76 genotypes and a single unique S. Typhi genotype was isolated from the cholecystectomy specimens of four patients with cholelithiasis. The high diversity in S. Typhi genotypes circulating in Makassar indicates that the number of carriers could be very large, which may complicate disease prevention and control
Associations between fruit and vegetable intake, leisure-time physical activity, sitting time and self-rated health among older adults : cross-sectional data from the WELL study
BackgroundLifestyle behaviours, such as healthy diet, physical activity and sedentary behaviour, are key elements of healthy ageing and important modifiable risk factors in the prevention of chronic diseases. Little is known about the relationship between these behaviours in older adults. The purpose of this study was to explore the relationship between fruit and vegetable (F&V) intake, leisure-time physical activity (LTPA) and sitting time (ST), and their association with self-rated health in older adults.MethodsThis cross-sectional study comprised 3,644 older adults (48% men) aged 55-65 years, who participated in the Wellbeing, Eating and Exercise for a Long Life ("WELL") study. Respondents completed a postal survey about their health and their eating and physical activity behaviours in 2010 (38% response rate). Spearman\u27s coefficient (rho) was used to evaluate the relationship between F&V intake, LTPA and ST. Their individual and shared associations with self-rated health were examined using ordinal logistic regression models, stratified by sex and adjusted for confounders (BMI, smoking, long-term illness and socio-demographic characteristics).ResultsThe correlations between F&V intake, LTPA and ST were low. F&V intake and LTPA were positively associated with self-rated health. Each additional serving of F&V or MET-hour of LTPA were associated with approximately 10% higher likelihood of reporting health as good or better among women and men. The association between ST and self-rated health was not significant in the multivariate analysis. A significant interaction was found (ST*F&V intake). The effect of F&V intake on self-rated health increased with increasing ST in women, whereas the effect decreased with increasing ST in men.ConclusionThis study contributes to the scarce literature related to lifestyle behaviours and their association with health indicators among older adults. The findings suggest that a modest increase in F&V intake, or LTPA could have a marked effect on the health of older adults. Further research is needed to fully understand the correlates and determinants of lifestyle behaviours, particularly sitting time, in this age group
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