Evidence for suppressed mid-Holocene northeastern Australian monsoon variability from coral luminescence

Summer monsoon rainfall in northeastern (NE) Australia exhibits substantial interannual variability resulting in highly variable river flows. The occurrence and magnitude of these seasonal river flows are reliably recorded in modern inshore corals as luminescent lines. Here we present reconstructed annual river flows for two ~120 year mid-Holocene windows based on luminescence measurements from five cores obtained from three separate coral colonies. We were able to cross-date the luminescence signatures in four cores from two of the colonies, providing confidence in the derived reconstruction. Present-day NE Australian rainfall and river flow are sensitive to El Niño–Southern Oscillation (ENSO) variability, with La Niña (El Niño) events typically associated with wetter (drier) monsoon seasons. Thus, our replicated and annually resolved coral records provide valuable insights into the northern Australian summer monsoon and ENSO variability at a key period (6 ka) when greenhouse gas levels and ice sheet cover were comparable to the preindustrial period but orbital forcing was different. Average modern and mid-Holocene growth characteristics were very similar, suggesting that sea surface temperatures off NE Australia at 6 kyr were also close to present values. The reconstructed river flow record suggests, however, that the mid-Holocene Australian summer monsoon was weaker, less variable from year to year (possibly indicative of reduced ENSO variability), and characterized by more within-season flood pulses than present. In contrast to today, the delivery of moisture appears to have been dominated by eastward propagating convective coupled waves associated with the Madden-Julian Oscillation

Localisation of mTOR complex proteins in embryonic stem cells: relationship with cell division and survival

The mammalian target of rapamycin (mTOR) regulates cell growth and proliferation in response to nutrients and growth factors. The role of mTOR in the biology of embryonic stem cells has not been extensively characterised. The principle aim of this research was to assess the feasibility of manipulating the mTOR pathway to provide bioprocessing improvements for the expansion and differentiation of embryonic stem cells. In order to achieve this aim, the cellular distribution and localisation of mTOR pathway phosphoproteins was assessed and the effect of pathway inhibition on ES cell proliferation and viability was characterised. The key findings of this study revealed that in mouse ES cells, mTOR pathway proteins were phosphorylated during mitosis. Secondly, inhibition of mTOR in growth factor-stimulated pluripotent stem cells impaired proliferation but not viability. Upon withdrawal of growth factors, cells lost their compact shape and exhibited a spread morphology. Under these conditions mTOR inhibition reduced the viability and proliferation of ‘compact’ cells but not ‘spread’ cells. Thus, during the expansion of ES cells the mTOR pathway may be stimulated. During early differentiation, inhibition of the pathway may improve the purity of the final cell preparation and reduce the prevalence of parent stem cells. In conclusion, the experimental findings discussed here show that temporal manipulation of the mTOR pathway in embryonic stem cells may provide bioprocessing advantages resulting in an increased yield of parent cell populations during expansion and increased purity of differentiated cells. The sensitivity of the mTOR pathway to the bioavailability of nutrients may offer a cost-effective route to optimising cell production in an industrial scale process. Further work to elucidate the role of the mTOR complex 2 in ES cell proliferation may provide an additional level of control to independently modulate cell proliferation and growth during expansion and differentiation

Pyrrolo- and pyridomorphinans:Non-selective opioid antagonists and delta opioid agonists/mu opioid partial agonists

Opioid ligands have found use in a number of therapeutic areas, including for the treatment of pain and opiate addiction (using agonists) and alcohol addiction (using antagonists such as naltrexone and nalmefene). The reaction of imines, derived from the opioid ligands oxymorphone and naltrexone, with Michael acceptors leads to pyridomorphinans with structures similar to known pyrrolo- and indolomorphinans. One of the synthesized compounds, 5e, derived from oxymorphone had substantial agonist activity at delta opioid receptors but not at mu and/or kappa opioid receptors and in that sense profiled as a selective delta opioid receptor agonist. The pyridomorphinans derived from naltrexone and naloxone were all found to be non-selective potent antagonists and as such could have utility as treatments for alcohol abuse

Constraining slow-roll inflation with WMAP and 2dF

We constrain slow-roll inflationary models using the recent WMAP data combined with data from the VSA, CBI, ACBAR and 2dF experiments. We find the slow-roll parameters to be $0 < \epsilon_1 < 0.032$ and $\epsilon_2 + 5.0 \epsilon_1 = 0.036 \pm 0.025$. For inflation models $V \propto \phi^{\alpha}$ we find that $\alpha< 3.9, 4.3$ at the 2$\sigma$ and $3\sigma$ levels, indicating that the $\lambda\phi^4$ model is under very strong pressure from observations. We define a convergence criterion to judge the necessity of introducing further power spectrum parameters such as the spectral index and running of the spectral index. This criterion is typically violated by models with large negative running that fit the data, indicating that the running cannot be reliably measured with present data.Comment: 8 pages RevTeX4 file with six figures incorporate

Impacts of climate change on coastal habitats, relevant to the coastal and marine environment around the UK

Coastal habitats are at risk from both direct (temperature, rainfall), and indirect (sea-level rise, coastal erosion) impacts due to a changing climate. Beyond the environmental impacts and ensuing habitat loss, the changing climate will have a significant societal impact to coastal communities ranging from health to livelihoods, as well as the loss of important ecosystem services such as coastal defence – particularly relevant with predicted increase in storminess. Vegetated coastal ecosystems sequester carbon – another ‘ecosystem service’ that could be disrupted due to climate change. There has been considerable recent attention to the potential role these habitats could play in climate mitigation, and also in transferring carbon across the land–sea interface. To understand the relative importance of these habitats within the global carbon cycle, coastal habitats need to be accounted for in national greenhouse gas inventories, and a true multidisciplinary catchment-to-coast approach to research is required. Management options exist that can reduce the immediate impacts of climate change, such as managed realignment and sediment recharge. Fixed landward coastal defences are becoming unsustainable and creating ‘coastal squeeze’, highlighting the need to work with natural processes to recreate more-natural shorelines where possible