Asymmetric root distributions reveal press–pulse responses in retreating coastal forests

The impacts of climate change on ecosystems are manifested in how organisms respond to episodic and continuous stressors. The conversion of coastal forests to salt marshes represents a prominent example of ecosystem state change, driven by the continuous stress of sea-level rise (press), and episodic storms (pulse). Here, we measured the rooting dimension and fall direction of 143 windthrown eastern red cedar (Juniperus virginiana) trees in a rapidly retreating coastal forest in Chesapeake Bay (USA). We found that tree roots were distributed asymmetrically away from the leading edge of soil salinization and towards freshwater sources. The length, number, and circumference of roots were consistently higher in the upslope direction than downslope direction, suggesting an active morphological adaptation to sea-level rise and salinity stress. Windthrown trees consistently fell in the upslope direction regardless of aspect and prevailing wind direction, suggesting that asymmetric rooting destabilized standing trees, and reduced their ability to withstand high winds. Together, these observations help explain curious observations of coastal forest resilience, and highlight an interesting nonadditive response to climate change, where adaptation to press stressors increases vulnerability to pulse stressors

Multi-scale theory and simulation of direct-gap group-IV semiconductor alloys

Alloying of Ge with other group-IV elements - C, Sn or Pb - represents a promising route to realise direct-gap group-IV semiconductors for applications in Si-compatible devices, including light-emitting diodes and lasers, as well as tunnelling field-effect transistors and multi-junction solar cells. To develop a quantitative understanding of the properties and potential of group-IV alloys, we have established a multi-scale simulation framework to enable predictive analysis of their structural and electronic properties. We provide an overview of these simulation capabilities, and describe previously overlooked fundamental aspects of the electronic structure evolution and indirect- to direct-gap transition in (Si)Ge1-x(C, Sn, Pb)x alloys. We further describe ongoing work related to exploiting this simulation platform to compute the optical and transport properties of (Si)Ge1-xSnx alloys and heterostructures

Acceptability of prison-based take-home naloxone programmes among a cohort of incarcerated men with a history of regular injecting drug use

Background: Take-home naloxone (THN) programmes are an evidence-based opioid overdose prevention initiative. Elevated opioid overdose risk following prison release means release from custody provides an ideal opportunity for THN initiatives. However, whether Australian prisoners would utilise such programmes is unknown. We examined the acceptability of THN in a cohort of male prisoners with histories of regular injecting drug use (IDU) in Victoria, Australia. Methods: The sample comprised 380 men from the Prison and Transition Health (PATH) Cohort Study; all of whom reported regular IDU in the 6 months prior to incarceration. We asked four questions regarding THN during the pre-release baseline interview, including whether participants would be willing to participate in prison-based THN. We describe responses to these questions along with relationships between before- and during-incarceration factors and willingness to participate in THN training prior to release from prison. Results: Most participants (81%) reported willingness to undertake THN training prior to release. Most were willing to resuscitate a friend using THN if they were trained (94%) and to be revived by a trained peer (91%) using THN. More than 10 years since first injection (adjusted odds ratio [AOR] 2.22, 95%CI 1.03-4.77), having witnessed an opioid overdose in the last 5 years (AOR 2.53, 95%CI 1.32-4.82), having ever received alcohol or other drug treatment in prison (AOR 2.41, 95%CI 1.14-5.07) and injecting drugs during the current prison sentence (AOR 4.45, 95%CI 1.73-11.43) were significantly associated with increased odds of willingness to participate in a prison THN programme. Not specifying whether they had injected during their prison sentence (AOR 0.37, 95%CI 0.18-0.77) was associated with decreased odds of willingness to participate in a prison THN training. Conclusion: Our findings suggest that male prisoners in Victoria with a history of regular IDU are overwhelmingly willing to participate in THN training prior to release. Factors associated with willingness to participate in prison THN programmes offer insights to help support the implementation and uptake of THN programmes to reduce opioid-overdose deaths in the post-release period

Case Reports1. A Late Presentation of Loeys-Dietz Syndrome: Beware of TGFβ Receptor Mutations in Benign Joint Hypermobility

Background: Thoracic aortic aneurysms (TAA) and dissections are not uncommon causes of sudden death in young adults. Loeys-Dietz syndrome (LDS) is a rare, recently described, autosomal dominant, connective tissue disease characterized by aggressive arterial aneurysms, resulting from mutations in the transforming growth factor beta (TGFβ) receptor genes TGFBR1 and TGFBR2. Mean age at death is 26.1 years, most often due to aortic dissection. We report an unusually late presentation of LDS, diagnosed following elective surgery in a female with a long history of joint hypermobility. Methods: A 51-year-old Caucasian lady complained of chest pain and headache following a dural leak from spinal anaesthesia for an elective ankle arthroscopy. CT scan and echocardiography demonstrated a dilated aortic root and significant aortic regurgitation. MRA demonstrated aortic tortuosity, an infrarenal aortic aneurysm and aneurysms in the left renal and right internal mammary arteries. She underwent aortic root repair and aortic valve replacement. She had a background of long-standing joint pains secondary to hypermobility, easy bruising, unusual fracture susceptibility and mild bronchiectasis. She had one healthy child age 32, after which she suffered a uterine prolapse. Examination revealed mild Marfanoid features. Uvula, skin and ophthalmological examination was normal. Results: Fibrillin-1 testing for Marfan syndrome (MFS) was negative. Detection of a c.1270G > C (p.Gly424Arg) TGFBR2 mutation confirmed the diagnosis of LDS. Losartan was started for vascular protection. Conclusions: LDS is a severe inherited vasculopathy that usually presents in childhood. It is characterized by aortic root dilatation and ascending aneurysms. There is a higher risk of aortic dissection compared with MFS. Clinical features overlap with MFS and Ehlers Danlos syndrome Type IV, but differentiating dysmorphogenic features include ocular hypertelorism, bifid uvula and cleft palate. Echocardiography and MRA or CT scanning from head to pelvis is recommended to establish the extent of vascular involvement. Management involves early surgical intervention, including early valve-sparing aortic root replacement, genetic counselling and close monitoring in pregnancy. Despite being caused by loss of function mutations in either TGFβ receptor, paradoxical activation of TGFβ signalling is seen, suggesting that TGFβ antagonism may confer disease modifying effects similar to those observed in MFS. TGFβ antagonism can be achieved with angiotensin antagonists, such as Losartan, which is able to delay aortic aneurysm development in preclinical models and in patients with MFS. Our case emphasizes the importance of timely recognition of vasculopathy syndromes in patients with hypermobility and the need for early surgical intervention. It also highlights their heterogeneity and the potential for late presentation. Disclosures: The authors have declared no conflicts of interes

Moduli spaces of complexes of sheaves

This thesis is on moduli spaces of complexes of sheaves and diagrams of such moduli spaces. The objects in these diagrams are constructed as geometric invariant theory quotients and the points in these quotients correspond to certain equivalence classes of complexes. The morphisms in these diagrams are constructed by taking direct sums with acyclic complexes. We then study the colimit of such a diagram and in particular are interested in studying the images of quasi-isomorphic complexes in the colimit. As part of this thesis we construct categorical quotients of a group action on unstable strata appearing in a stratification associated to a complex projective scheme with a reductive group action linearised by an ample line bundle. We study this stratification for a closed subscheme of a quot scheme parametrising quotient sheaves over a complex projective scheme and relate the Harder-Narasimhan types of unstable sheaves with the unstable strata in the associated stratification. We also study the stratification of a parameter space for complexes with respect to a linearisation determined by certain stability parameters and show that a similar result holds in this case. The objects in these diagrams are indexed by different Harder-Narasimhan types for complexes and are quotients of parameter schemes for complexes of this fixed Harder-Narasimhan type. This quotient is given by a choice of linearisation of the action and so the diagrams depend on these choices. We conjecture that these choices can be made so that for any quasi-isomorphism between complexes representing points in this diagram both complexes are identified in the colimit of this diagram.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Licit and illicit quetiapine use among IDRS participants

This paper presents a preliminary examination of the use of quetiapine (an antipsychotic drug) amongst a broader sample of people who inject drugs. Quetiapine fumarate is an atypical antipsychotic drug which has become more commonly prescribed in Australia for certain mental health conditions in the last decade. The Therapeutic Goods Association of Australia (TGA) originally approved quetiapine for use in the treatment of schizophrenia in 2000. Subsequent reviews of the drug by the TGA in 2007 and 2009 have resulted in it also being approved for treatment of bipolar disorder. More recently, in 2010, it was approved for use as a second-line treatment (i.e. where other treatments have proven ineffective or inappropriate) for generalised anxiety disorder and major depressive disorder. Potentially serious side effects of quetiapine include QTc interval prolongation (a cardiac effect which can result in sudden death), weight gain and ex-pyramidal symptoms (movement disorders). Despite a number of case reports from several countries particularly amongst polysubstance users, there has been little examination of quetiapine use amongst broader samples of drug users. In 2010 and 2011, a number of key experts participating in the Illicit Drug Reporting System (IDRS) raised concerns about quetiapine. When speaking more generally about use of anti-psychotic drugs among people who inject drugs (PWID), quetiapine in particular was raised as an emerging substance of recent use. Discussion of an emerging street market for this drug and its use among those without psychotic disorders occurred during interviews with key experts. Key experts expressed concern with the apparent effects of the medication, mostly in relation to antisocial behaviours, with experiences of users seeming “unreasonable”, “agitated” and “oblivious to the world around them”. One key expert reported that clients had been referred for help with “withdrawing” from this medication. As a result of these reports, specific questions about licit and illicit quetiapine use were included in the 2011 IDRS survey. In this Bulletin we present a preliminary examination of quetiapine use amongst a broader sample of PWID through analysis of findings from the 2011 IDRS, with a specific focus on Victoria, which had the highest prevalence of use in Australia. Key findings: Quetiapine use and associated problems have been documented overseas ƒƒLifetime quetiapine use was reported by 41% of the 2011 IDRS sample, and recent use was reported by 22% of the sample ƒƒ Recent mental health issues and recent benzodiazepine use were prevalent among those using both licit and illicit quetiapine ƒƒ Ice use was frequently reported by those reporting illicit quetiapine use ƒƒ Quetiapine use among PWID warrants further research and monitorin

Modelling the impact of condom distribution on the incidence and prevalence of sexually transmitted infections in an adult male prison system

No grant i

Prisons, needles and OHS

Drug use occurs in prisons despite the strict prohibitionist approach that is taken. In Australia, prison needle and syringe supply is currently unregulated and uncontrolled. Prison officers risk sustaining needlestick injuries when conducting searches of inmates, cells and other areas, thereby risking bloodborne virus infections, such as HIV and hepatitis C. As such, there is a need to explore whether a regulated needle and syringe program (NSP) in Australian prisons could contribute to a safer workplace. International experience has shown that regulated prison NSPs do contribute to institutional safety, and that they do not result in syringes being used as weapons. The introduction of prison-regulated and controlled NSPs would be consistent with efforts to comply with OHS principles, as well as the approved standards for corrections in Australia