592 research outputs found
Strong Dynamo Action in Rapidly Rotating Suns
Stellar dynamos are driven by complex couplings between rotation and
turbulent convection, which drive global-scale flows and build and rebuild
stellar magnetic fields. When stars like our sun are young, they rotate much
more rapidly than the current solar rate. Observations generally indicate that
more rapid rotation is correlated with stronger magnetic activity and perhaps
more effective dynamo action. Here we examine the effects of more rapid
rotation on dynamo action in a star like our sun. We find that vigorous dynamo
action is realized, with magnetic field generated throughout the bulk of the
convection zone. These simulations do not possess a penetrative tachocline of
shear where global-scale fields are thought to be organized in our sun, but
despite this we find strikingly ordered fields, much like sea-snakes of
toroidal field, which are organized on global scales. We believe this to be a
novel finding.Comment: 8 pages, 4 figs. Published in conference proceedings "Unsolved
Problems in Stellar Physics", held July 2-6 2007 Cambridge, Englan
Ultrasound Mediated Gemcitabine Delivery Reduces the Normal-Tissue Toxicity of Chemoradiation Therapy in a Muscle-Invasive Bladder Cancer Model
Purpose: Chemoradiation is the standard of care in muscle-invasive bladder. While agents such as gemcitabine can enhance tumour radiosensitisation, their side effects can limit patient eligibility and treatment efficacy. Here we investigate ultrasound and microbubbles for targeting gemcitabine delivery to reduce normal tissue toxicity in a murine orthotopic MIBC model.
Materials and Methods: CD1-nude mice were injected orthotopically with RT112 bladder tumour cells. Conventional chemoradiation involved injecting gemcitabine (10 mg/kg) before 6 Gy targeted irradiation of the bladder area using a Small Animal Radiation Research Platform (SARRP). Ultrasound-mediated gemcitabine delivery (10 mg/kg gemcitabine) involved either co-administration of microbubbles with gemcitabine or conjugating gemcitabine onto microbubbles followed by exposure to ultrasound (1.1 MHz centre frequency, 1 MPa peak negative pressure, 1% duty cycle and 0.5 Hz pulse repetition frequency), prior to SARRP irradiation. The effect of ultrasound and microbubbles alone was also tested. Tumour volumes were measured by 3D ultrasound imaging. Acute normal tissue toxicity from 12 Gy to the lower bowel area was assessed using an intestinal crypt assay in mice culled. 3.75 days post-treatment.
Results: Significant tumour growth delay was observed with conventional chemoradiation and both microbubble groups (p
Conclusions: Ultrasound and microbubbles offer a promising new approach for improving chemoradiation therapy in muscle-invasive bladder cancer, maintaining tumour growth delay but with reduced acute intestinal toxicity compared to conventional chemoradiation therapy.</p
Self-Reported Head Injury and Risk of Late-Life Impairment and AD Pathology in an AD Center Cohort
Aims: To evaluate the relationship between self-reported head injury and cognitive impairment, dementia, mortality, and Alzheimer\u27s disease (AD)-type pathological changes. Methods: Clinical and neuropathological data from participants enrolled in a longitudinal study of aging and cognition (n = 649) were analyzed to assess the chronic effects of self-reported head injury. Results: The effect of self-reported head injury on the clinical state depended on the age at assessment: for a 1-year increase in age, the OR for the transition to clinical mild cognitive impairment (MCI) at the next visit for participants with a history of head injury was 1.21 and 1.34 for the transition from MCI to dementia. Without respect to age, head injury increased the odds of mortality (OR = 1.54). Moreover, it increased the odds of a pathological diagnosis of AD for men (OR = 1.47) but not women (OR = 1.18). Men with a head injury had higher mean amyloid plaque counts in the neocortex and entorhinal cortex than men without. Conclusions: Self-reported head injury is associated with earlier onset, increased risk of cognitive impairment and dementia, increased risk of mortality, and AD-type pathological changes
Data-driven recommendations for enhancing real-time natural hazard warnings, communication, and response
The effectiveness and adequacy of natural hazard warnings hinges on the
availability of data and its transformation into actionable knowledge for the
public. Real-time warning communication and emergency response therefore need
to be evaluated from a data science perspective. However, there are currently
gaps between established data science best practices and their application in
supporting natural hazard warnings. This Perspective reviews existing
data-driven approaches that underpin real-time warning communication and
emergency response, highlighting limitations in hazard and impact forecasts.
Four main themes for enhancing warnings are emphasised: (i) applying
best-practice principles in visualising hazard forecasts, (ii) data
opportunities for more effective impact forecasts, (iii) utilising data for
more localised forecasts, and (iv) improving data-driven decision-making using
uncertainty. Motivating examples are provided from the extensive flooding
experienced in Australia in 2022. This Perspective shows the capacity for
improving the efficacy of natural hazard warnings using data science, and the
collaborative potential between the data science and natural hazards
communities
The Methodology of Modern Macroeconomics and the Descriptive Approach to Discounting
Critics of modern macroeconomics often raise concerns about unwarranted welfare conclusions and data mining. This paper illustrates these concerns with a thought experiment, based on the debate in environmental economics about the appropriate discount rate in climate change analyses: I set up an economy where a social evaluator wants to determine the optimal time path of emission levels, and seeks advice for this from an old-style neo-classical macroeconomist and a new neo-classical (modern) macroeconomist; I then describe how both economists analyze the economy, their policy advice, and their mistakes. I then use the insights from this thought experiment to point out some pitfalls of the modern macroeconomic methodology
Glucose effects on gastric motility and tone evoked from the rat dorsal vagal complex
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66102/1/j.1469-7793.2001.t01-1-00141.x.pd
Science in neo-Victorian poetry
This article considers the work of three contemporary poets and their engagement, in verse, with Victorian science. Beginning with the outlandish âtheoriesâ of Mick Imlahâs âThe Zoologistâs Bathâ (1983), it moves on to two works of biografiction â Anthony Thwaiteâs poem âAt Marychurchâ (1980), which outlines Philip Henry Gosseâs doomed attempts to unite evolution and Christianity, and Ruth Padelâs Darwin: A Life in Poems (2009). Starting off with John Glendeningâs idea that science in neo-Victorian fiction, if fully embraced, provides an opportunity for self-revelation to characters, this article explores the rather less happy resolutions of each of these poems, while in addition discussing the ways in which these poems perform the formal changes and mutability discussed within them
Genome-wide association study identifies a variant in HDAC9 associated with large vessel ischemic stroke
Genetic factors have been implicated in stroke risk but few replicated associations have been reported. We conducted a genome-wide association study (GWAS) in ischemic stroke and its subtypes in 3,548 cases and 5,972 controls, all of European ancestry. Replication of potential
signals was performed in 5,859 cases and 6,281 controls. We replicated reported associations between variants close to PITX2 and ZFHX3 with cardioembolic stroke, and a 9p21 locus with large vessel stroke. We identified a novel association for a SNP within the histone deacetylase 9(HDAC9) gene on chromosome 7p21.1 which was associated with large vessel stroke including additional replication in a further 735 cases and 28583 controls (rs11984041, combined P =
1.87Ă10â11, OR=1.42 (95% CI) 1.28-1.57). All four loci exhibit evidence for heterogeneity of effect across the stroke subtypes, with some, and possibly all, affecting risk for only one subtype. This suggests differing genetic architectures for different stroke subtypes
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