4,287 research outputs found
The vegetation of Tasman Peninsula
Although its area is less than 1% of Tasmania, Tasman Peninsula possesses more than one-
third of the total native vascular plants of the State. The number of species present is close
to that predicted by the theories of island biogeography. There are 70 Tasmanian endemic
vascular plant species present, representing 13 % of the total. This figure is lower than that
expected on a proportional basis due to the absence from the peninsula of the distinctively
Tasmanian alpine, wet and oligotrophic western environments. There are two vascular plants
known only from the peninsula. Nevertheless there is a distinctly local flavour to the flora due
to those components held in common with other predominantly lowland dolerite parts of
southeastern Tasmania.
The vegetation types present on the peninsula include coastal heaths, dune vegetation and
wetlands, dry and wet sc!erophyll forests and some small areas ofsubalpine scrub and rainforests.
The structure and composition of the vegetation on the peninsula reflect climatic, topographic,
firing and biotic influences. Thus dry sclerophyll forests grade into wet sclerophyll forests as
moisture availability increases . The forests grade into heaths as sites become more exposed to
the prevailing salt-laden onshore winds. Within a particular vegetation type, the
composition is influenced by local climate and landform but is also attributable to local
drainage conditions, geological substrate and fire history.
The plant species and communities present are, some exceptions, moderately well-
conserved, but sensitivity in future management will be required to retain the character conferred
on the peninsula by its native vegetation
Memory fMRI predicts verbal memory decline after anterior temporal lobe resection.
To develop a clinically applicable memory functional MRI (fMRI) method of predicting postsurgical memory outcome in individual patients
Automated hippocampal segmentation in patients with epilepsy: Available free online
Hippocampal sclerosis, a common cause of refractory focal epilepsy, requires hippocampal volumetry for accurate diagnosis and surgical planning. Manual segmentation is time-consuming and subject to interrater/intrarater variability. Automated algorithms perform poorly in patients with temporal lobe epilepsy. We validate and make freely available online a novel automated method
Stability, Structure and Scale: Improvements in Multi-modal Vessel Extraction for SEEG Trajectory Planning
Purpose Brain vessels are among the most critical landmarks that need to be assessed for mitigating surgical risks in stereo-electroencephalography (SEEG) implantation. Intracranial haemorrhage is the most common complication associated with implantation, carrying signi cant associated morbidity. SEEG planning is done pre-operatively to identify avascular trajectories for the electrodes. In current practice, neurosurgeons have no assistance in the planning of electrode trajectories. There is great interest in developing computer assisted planning systems that can optimise the safety pro le of electrode trajectories, maximising the distance to critical structures. This paper presents a method that integrates the concepts of scale, neighbourhood structure and feature stability with the aim of improving robustness and accuracy of vessel extraction within a SEEG planning system. Methods The developed method accounts for scale and vicinity of a voxel by formulating the problem within a multi-scale tensor voting framework. Feature stability is achieved through a similarity measure that evaluates the multi-modal consistency in vesselness responses. The proposed measurement allows the combination of multiple images modalities into a single image that is used within the planning system to visualise critical vessels. Results Twelve paired datasets from two image modalities available within the planning system were used for evaluation. The mean Dice similarity coe cient was 0.89 ± 0.04, representing a statistically signi cantly improvement when compared to a semi-automated single human rater, single-modality segmentation protocol used in clinical practice (0.80 ±0.03). Conclusions Multi-modal vessel extraction is superior to semi-automated single-modality segmentation, indicating the possibility of safer SEEG planning, with reduced patient morbidity
Does a physically active lifestyle attenuate the association between alcohol consumption and mortality risk? Findings from the UK biobank
Alcohol consumption is common across Western culture, despite its associations with adverse health outcomes, including cancer and cardiovascular disease (CVD). Physical activity (PA) has beneficial effects on many alcohol related outcomes, with data suggesting PA may offset the association between alcohol consumption and mortality. This study examined the joint associations of PA and alcohol on all-cause, CVD and cancer mortality. Participants were recruited between 2006 and 2010 in the United Kingdom. Alcohol consumption was categorised based on current UK guidelines (14 units/week). PA was categorised based on the Metabolic Task Equivalent of PA as low, moderate and high. Data were analysed using Cox proportional-hazard models. The final analysis, conducted in 2019, included 297,988 adults aged ≥40. Over an average follow-up of 6.9 years, 6079 deaths were recorded, including 1219 CVD deaths and 3112 cancer deaths. We observed greater point estimates for risk of all-cause mortality among low PA individuals who consumed alcohol at the same level as active individuals. For example, low PA participants who reported alcohol consumption ≥double guidelines had a greater HR (1.55, 95% CI 1.25, 1.93) than active individuals (moderate PA HR 1.21, 95% CI 0.95, 1.54; high PA HR 1.21, 95% CI 1.00, 1.46). Considering CVD, we observed a similar trend with lower point estimates of risk of mortality among active individuals. We found some evidence that PA modified the associations of alcohol and all-cause and CVD mortality in this large population sample of British adults
Association between TV viewing and heart disease mortality: observational study using negative control outcome
AIMS: Sedentary behaviour (particularly television (TV) viewing) is thought to be a risk factor for cardiovascular disease. We employed a negative control outcome to explore whether the association between TV viewing and heart disease mortality is explained by confounding. METHODS: The sample was drawn from the UK Biobank study and comprised 479 658 participants (aged 56.5±8.0 years; 45.7% men) followed up over a mean of 10.4 years. TV viewing was measured from self-report. RESULTS: There were 1437 ischaemic heart disease (IHD) deaths, and 214 accidental deaths (employed as the negative control outcome). TV viewing was related to the following confounding variables: age, smoking, alcohol, diet, obesity, physical inactivity, cardiovascular disease and education. The confounding structures were similar for both outcomes. TV viewing (per hour/d) was associated with IHD (hazard ratio (HR)=1.30, 95% CI, 1.27 to 1.33) and accidental death (HR=1.15, 95% CI, 1.07 to 1.24) in unadjusted models. Associations were attenuated for both outcomes and were considerably converged after adjustment for confounders; IHD (HR=1.09, 95% CI, 1.06 to 1.12) and accidental death (HR=1.06, 95% CI, 0.98 to 1.15). CONCLUSION: The pattern of results for TV with an implausible outcome mirrored that of IHD, suggesting that observed associations between TV and heart disease are likely to be driven by confounding
Effects of movement velocity and training frequency of resistance exercise on functional performance in older adults: a randomised controlled trial
Objectives: To investigate the effects that high-velocity, low-load (HVLL) and low-velocity, high-load (LVHL) resistance exercise, performed once or twice-weekly, have on indices of functional performance (primary outcome), maximal strength, and body composition (secondary outcomes) in older adults. Methods: In a randomised, controlled, multi-armed, parallel design, 54 moderately-highly active, but resistance exercise naïve older adults (aged 60–79 years), attended baseline and post-10-week intervention assessment sessions. Physical and functional assessments were completed, and predicted one-repetition maximums (1-RM) were obtained for eight exercises. Participants were then randomised into one of five conditions: HVLL once-weekly (HVLL1: n = 11) or twice-weekly (HVLL2: n = 11), LVHL once-weekly (LVHL1: n = 10) or twice-weekly (LVHL2: n = 11), no-exercise control condition (CON: n = 11). The HVLL conditions completed 3 sets of 14 repetitions at 40% 1-RM and the LVHL conditions, 3 sets of 7 repetitions at 80% 1-RM. In total, 50 participants completed all testing and were included in analyses. Results: Only LVHL2 improved 30-sec chair stand performance (p =.035; g = 0.89), arm curls (p =.011; g = 1.65) and grip-strength (p =.015; g = 0.34) compared to CON. LVHL2 improved maximal strength compared to CON for 7/8 exercises (p <.05). Whereas, LVHL1 and HVLL2 only improved seated row and chest press compared to CON (p <.05). Conclusion: Possibly due to the lower intensity nature of the HVLL conditions, LVHL, twice-weekly was most beneficial for improving functional performance and strength in moderately-highly active older adults. Therefore, we recommend that exercise professionals ensure resistance exercise sessions have sufficient intensity of effort and volume, in order to maximise functional performance and strength gains in older adults.
Large conductance Ca²⁺-activated K⁺ (BK) channels promote secretagogue-induced transition from spiking to bursting in murine anterior pituitary corticotrophs.
This is the final version of the article. Available from Wiley via the DOI in this record.Anterior pituitary corticotroph cells are a central component of the hypothalamic-pituitary-adrenal (HPA) axis essential for the neuroendocrine response to stress. Corticotrophs are excitable cells that receive input from two hypothalamic secretagogues, corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP) to control the release of adrenocorticotrophic hormone (ACTH). Although corticotrophs are spontaneously active and increase in excitability in response to CRH and AVP the patterns of electrical excitability and underlying ionic conductances are poorly understood. In this study, we have used electrophysiological, pharmacological and genetic approaches coupled with mathematical modelling to investigate whether CRH and AVP promote distinct patterns of electrical excitability and to interrogate the role of large conductance calcium- and voltage-activated potassium (BK) channels in spontaneous and secretagogue-induced activity. We reveal that BK channels do not play a significant role in the generation of spontaneous activity but are critical for the transition to bursting in response to CRH. In contrast, AVP promotes an increase in single spike frequency, a mechanism independent of BK channels but dependent on background non-selective conductances. Co-stimulation with CRH and AVP results in complex patterns of excitability including increases in both single spike frequency and bursting. The ability of corticotroph excitability to be differentially regulated by hypothalamic secretagogues provides a mechanism for differential control of corticotroph excitability in response to different stressors.P.J.D. was supported by an MRC PhD studentship in the College
of Medicine and Veterinary Medicine, University of Edinburgh.
Work was supported by grants to M.J.S. and P.R. from the
Wellcome Trust (082407), to M.J.S. from MRC (J008893), and to
R.B. and J.T. from the National Institutes of Health (DK43200)
Sleep and physical activity in relation to all-cause, cardiovascular disease and cancer mortality risk
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