An understanding of past hydroclimatic variability is critical to resolving the significance of recent recorded trends in Australian precipitation and informing climate models. Our aim was to ...reconstruct past hydroclimatic variability in semi-arid northwest Australia to provide a longer context within which to examine a recent period of unusually high summer-autumn precipitation. We developed a 210-year ring-width chronology from Callitris columellaris, which was highly correlated with summer-autumn (Dec-May) precipitation (r = 0.81; 1910-2011; p < 0.0001) and autumn (Mar-May) self-calibrating Palmer drought severity index (scPDSI, r = 0.73; 1910-2011; p < 0.0001) across semi-arid northwest Australia. A linear regression model was used to reconstruct precipitation and explained 66% of the variance in observed summer-autumn precipitation. Our reconstruction reveals inter-annual to multi-decadal scale variation in hydroclimate of the region during the last 210 years, typically showing periods of below average precipitation extending from one to three decades and periods of above average precipitation, which were often less than a decade. Our results demonstrate that the last two decades (1995-2012) have been unusually wet (average summer-autumn precipitation of 310 mm) compared to the previous two centuries (average summer-autumn precipitation of 229 mm), coinciding with both an anomalously high frequency and intensity of tropical cyclones in northwest Australia and the dominance of the positive phase of the Southern Annular Mode.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The use of clozapine requires monitoring the absolute neutrophil count because of the risk of agranulocytosis, but other potentially fatal adverse events associated with clozapine (specifically, ...myocarditis and cardiomyopathy) do not have mandatory procedures. We performed a systematic review of English-language articles to synthesize an evidence-based approach for myocarditis and cardiomyopathy monitoring. Articles published from January 1988 through February 2017 were identified through a search of Ovid MEDLINE, Ovid Embase, Ovid Cochrane Database of Systematic Reviews, Web of Science, Scopus, and Google Scholar. Selected articles were required to relate to myocarditis or cardiomyopathy in humans from exposure to clozapine. A total of 144 articles were included. Recommendations varied widely. Some authors recommended baseline laboratory monitoring, with or without follow-up testing, for C-reactive protein, creatine kinase MB, and troponin. Electrocardiography was commonly recommended, and echocardiography was less commonly recommended. The expense of monitoring was a consideration. A unanimous recommendation was to stop the use of clozapine and seek a cardiovascular consultation if myocarditis or cardiomyopathy is suspected. Although there is general agreement on which tests to perform for confirming myocarditis and cardiomyopathy, preemptive screening for these clozapine-induced conditions is controversial, and cost and barriers for the use of clozapine are concerns. For asymptomatic patients receiving clozapine, testing could include baseline electrocardiography, echocardiography as part of a cardiac consultation if patients have cardiac disease or risk factors, and monitoring of C-reactive protein and troponin as indicated.
Making decisions is central to the exercise of control over one's well-being. Many individuals with serious mental illness (SMI) experience limitations in their decision-making capacity. These ...individuals have often been placed under legal guardianship and substitute decision makers have been appointed to make decisions on their behalf. More recently, supported decision making (SDM) has emerged as a possible alternative in some cases. SDM involves recruitment of trusted supports to enhance an individual's capacity in the decision-making process, enabling him or her to retain autonomy in life decisions. This overview examines issues associated with decision-making capacity in SMI, frameworks of substitute decision making and SDM, and emerging empirical research on SDM.
This is an overview of the medical and legal literature on decision making capacity and supported decision making for persons with SMI.
Many but not all individuals with SMI exhibit decrements in decision-making capacity and skill, in part due to cognitive impairment. There are no published data on rates of substitute decision making/guardianship or SDM for SMI. Only three empirical studies have explored SDM in this population. These studies suggest that SDM is viewed as an acceptable and potentially superior alternative to substitute decision making for patients and their caretakers.
SDM is a promising alternative to substitute decision making for persons with SMI. Further empirical research is needed to clarify candidates for SDM, decisions in need of support, selection of supporters, guidelines for the SDM process, integration of SDM with emerging technological platforms, and outcomes of SDM. Recommendations for implementation of and research on SDM for SMI are provided.
Accurate methods to predict solubility from molecular structure are highly sought after in the chemical sciences. To assess the state of the art, the American Chemical Society organized a “Second ...Solubility Challenge” in 2019, in which competitors were invited to submit blinded predictions of the solubilities of 132 drug-like molecules. In the first part of this article, we describe the development of two models that were submitted to the Blind Challenge in 2019 but which have not previously been reported. These models were based on computationally inexpensive molecular descriptors and traditional machine learning algorithms and were trained on a relatively small data set of 300 molecules. In the second part of the article, to test the hypothesis that predictions would improve with more advanced algorithms and higher volumes of training data, we compare these original predictions with those made after the deadline using deep learning models trained on larger solubility data sets consisting of 2999 and 5697 molecules. The results show that there are several algorithms that are able to obtain near state-of-the-art performance on the solubility challenge data sets, with the best model, a graph convolutional neural network, resulting in an RMSE of 0.86 log units. Critical analysis of the models reveals systematic differences between the performance of models using certain feature sets and training data sets. The results suggest that careful selection of high quality training data from relevant regions of chemical space is critical for prediction accuracy but that other methodological issues remain problematic for machine learning solubility models, such as the difficulty in modeling complex chemical spaces from sparse training data sets.
Eastern Australia recently experienced an intense drought (Millennium Drought, 2003–2009) and record‐breaking rainfall and flooding (austral summer 2010–2011). There is some limited evidence for a ...climate change contribution to these events, but such analyses are hampered by the paucity of information on long‐term natural variability. Analyzing a new reconstruction of summer (December–January–February) Palmer Drought Severity Index (the Australia‐New Zealand Drought Atlas; ANZDA, 1500–2012 Common Era), we find moisture deficits during the Millennium Drought fall within the range of the last 500 years of natural hydroclimate variability. This variability includes periods of multidecadal drought in the 1500s more persistent than any event in the historical record. However, the severity of the Millennium Drought, which was caused by autumn (March‐April‐May) precipitation declines, may be underestimated in the ANZDA because the reconstruction is biased toward summer and antecedent spring (September‐October‐November) precipitation. The pluvial in 2011, however, which was characterized by extreme summer rainfall faithfully captured by the ANZDA, is likely the wettest year in the reconstruction for Coastal Queensland. Climate projections (Representative Concentration Pathways (RCP) 8.5 scenario) suggest that eastern Australia will experience long‐term drying during the 21st century. While the contribution of anthropogenic forcing to recent extremes remains an open question, these projections indicate an amplified risk of multiyear drought anomalies matching or exceeding the intensity of the Millennium Drought.
Key Points
Recent extremes (the Millennium Drought and 2011 pluvial) are compared to a 500‐year soil moisture reconstruction
2011 was likely the wettest year in the record for Coastal Queensland
Climate projections indicate substantially increased risk of droughts ≥ the magnitude of the Millennium Drought
Our understanding of the full range of natural variability in streamflow, including how modern flow compares to the past, is poorly understood for the Upper Indus Basin because of short instrumental ...gauge records. To help address this challenge, we use Hierarchical Bayesian Regression with partial pooling to develop six centuries long (1394–2008 CE) streamflow reconstructions at three Upper Indus Basin gauges (Doyian, Gilgit, and Kachora), concurrently demonstrating that Hierarchical Bayesian Regression can be used to reconstruct short records with interspersed missing data. At one gauge (Partab Bridge), with a longer instrumental record (47 years), we develop reconstructions using both Bayesian regression and the more conventionally used principal components regression. The reconstructions produced by principal components regression and Bayesian regression at Partab Bridge are nearly identical and yield comparable reconstruction skill statistics, highlighting that the resulting tree ring reconstruction of streamflow is not dependent on the choice of statistical method. Reconstructions at all four reconstructions indicate that flow levels in the 1990s were higher than mean flow for the past six centuries. While streamflow appears most sensitive to accumulated winter (January–March) precipitation and summer (May–September) temperature, with warm summers contributing to high flow through increased melt of snow and glaciers, shifts in winter precipitation and summer temperatures cannot explain the anomalously high flow during the 1990s. Regardless, the sensitivity of streamflow to summer temperatures suggests that projected warming may increase streamflow in coming decades, though long‐term water risk will additionally depend on changes in snowfall and glacial mass balance.
Key Points
Tree ring reconstructions of streamflow in the Upper Indus Basin show wetter conditions in the 1990s compared to the last 600 years
Reconstructions are insensitive to the choice of statistical method used (principal components versus Bayesian regression)
Streamflow is most sensitive to winter precipitation and summer temperature, but anomalies in these seasons cannot explain recent high flow
Proxy records have provided major insights into the variability of past climates over long timescales. However, for much of the Southern Hemisphere, the ability to identify spatial patterns of past ...climatic variability is constrained by the sparse distribution of proxy records. This is particularly true for mainland Australia, where relatively few proxy records are located. Here, we (1) assess the potential to use existing proxy records in the Australasian region-starting with the only two multi-century tree-ring proxies from mainland Australia-to reveal spatial patterns of past hydroclimatic variability across the western third of the continent, and (2) identify strategic locations to target for the development of new proxy records. We show that the two existing tree-ring records allow robust reconstructions of past hydroclimatic variability over spatially broad areas (i.e. > 3° × 3°) in inland north- and south-western Australia. Our results reveal synchronous periods of drought and wet conditions between the inland northern and southern regions of western Australia as well as a generally anti-phase relationship with hydroclimate in eastern Australia over the last two centuries. The inclusion of 174 tree-ring proxy records from Tasmania, New Zealand and Indonesia and a coral record from Queensland did not improve the reconstruction potential over western Australia. However, our findings suggest that the addition of relatively few new proxy records from key locations in western Australia that currently have low reconstruction skill will enable the development of a comprehensive drought atlas for the region, and provide a critical link to the drought atlases of monsoonal Asia and eastern Australia and New Zealand.
Optic Nerve Head Drusen: An Update Palmer, Edward; Gale, Jesse; Crowston, Jonathan G. ...
Neuro-ophthalmology (Amsterdam : Aeolus Press. 1980),
11/2018, Letnik:
42, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Optic nerve head drusen are benign acellular calcium concretions that usually form early in life, just anterior to the lamina cribrosa. Improving imaging using optical coherence tomography suggests ...they are common and may be present in many clinically normal discs. These drusen may change in appearance in early life, but are generally stable in adulthood, and may be associated with visual field defects, anterior ischaemic optic neuropathy, or rarer complications. Based on long-term clinical data and optical coherence tomography, we propose a refined hypothesis as to the cause of optic disc drusen. Here we summarise recent findings and suggest future studies to better understand the forces involved.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Recent extremes of flood and drought across Australia have raised questions about the recurrence of such rare events and highlighted the importance of understanding multi-decadal climate variability. ...However, instrumental records over the past century are too short to adequately characterise climate variability on multi-decadal and longer timescales or robustly determine extreme event frequencies and their duration. Palaeoclimate reconstructions can provide much-needed information to help address this problem. Here, we use the 600-year hydroclimate record captured in the eastern Australian and New Zealand Drought Atlas (ANZDA) to analyse drought and pluvial frequency trends for East Australian Natural Resource Management (NRM) clusters. This partitioning of the drought atlas grid points into recognised biophysical areas (i.e. NRM clusters) revealed their differences and similarities in drought intensity and pluvial events over time. We find sustained multi-decadal periods of a wet–dry geographic 'seesaw' between eastern to central and southern NRMs (e.g. 1550–1600 CE and 1700–1750 CE). In contrast, other periods reveal spatially consistent wetting (e.g. 1500–1550 CE) or drying (e.g. 1750–1800 CE). Emerging hot spot analysis further shows that some areas that appear naturally buffered from severe drought during the instrumental period have a greater exposure risk when the longer 600-year record is considered. These findings are particularly relevant to management plans when dealing with the impacts of climate extremes developed at regional scales. Our results demonstrate that integrating and extending instrumental records with palaeoclimate datasets will become increasingly important for developing robust and locally specific extreme event frequency information for managing water resources.
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