1,025 research outputs found

    The Contemporary Australian Intelligence Domain - A Multi Dimension Examination

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    In the complex and interconnected post 9/11 world the roles and functions of intelligence have evolved beyond being a secret capability of governments focused on national security needs. Intelligence has become recognised as a critical function necessary to support decision making across the full breadth of government and corporate activity. The concept of an intelligence community being purely national security centric and bounded by secrecy has become limited. Intelligence in support of decision making has become a far broader domain than previously believed. This paper investigates the degree of intelligence embedded‐ness across government agencies and departments at the federal, state and local levels. Findings reveal that in excess of 75 discrete intelligence capabilities were identified, categorized by theme before being stratified into a three tier hierarchal intelligence domain map. Many of these categories were not in support of national security per se, but rather in support of broader government decision making

    Fractures in shale: the significance of igneous intrusions for groundwater flow

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    Research in Cretaceous shales from West Africa has demonstrated that significant permeability can develop within shales at shallow depths (1 m day−1. Much of the variation in permeability is related to the degree of burial metamorphism, with shales that have been altered and that approach the anchizone having the highest permeability and those that are largely unaltered (early diagenetic zone) having the lowest permeability. However, further research targeting largely unaltered shales dominated by smectite clay has shown that the presence of small igneous intrusions can radically alter the hydrogeology. Twenty-four exploratory boreholes were drilled into smectite-dominated shale and nine of these boreholes were targeted to small dolerite intrusions within the shale. The dolerite was intensely fractured at the intrusion edge, with significant zeolite growth along the fracture surfaces. The permeability in the fractured dolerite was the highest measured in any shale borehole, with transmissivities of up to 60 m2 day−1 measured from pumping tests. Fracturing was less where dolerite was intruded into sandstones, however, and the measured transmissivity was lower (<0.5 m2 day−1). We postulate that the low permeability and high water content of the shale enabled high pressures to develop during intrusion, facilitating the development of fractures along the intrusion contact zone

    Archaean and Proterozoic diamond growth from contrasting styles of large-scale magmatism

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    Precise dating of diamond growth is required to understand the interior workings of the early Earth and the deep carbon cycle. Here we report Sm-Nd isotope data from 26 individual garnet inclusions from 26 harzburgitic diamonds from Venetia, South Africa. Garnet inclusions and host diamonds comprise two compositional suites formed under markedly different conditions and define two isochrons, one Archaean (2.95 Ga) and one Proterozoic (1.15 Ga). The Archaean diamond suite formed from relatively cool fluid-dominated metasomatism during rifting of the southern shelf of the Zimbabwe Craton. The 1.8 billion years younger Proterozoic diamond suite formed by melt-dominated metasomatism related to the 1.1 Ga Umkondo Large Igneous Province. The results demonstrate that resolving the time of diamond growth events requires dating of individual inclusions, and that there was a major change in the magmatic processes responsible for harzburgitic diamond formation beneath Venetia from the Archaean to the Proterozoic

    An investigation of tinnitus using behavioural and functional imaging measures

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    Tinnitus is the phantom perception of sound. For some people tinnitus can have a detrimental impact on their quality of life. Negative emotional feelings associated with tinnitus play a major role in enhancing and maintaining its continued presence. Despite its high prevalence across the world, its neurophysiological underpinnings remain elusive and there is no universal cure. This thesis utilises data derived from an open-label, non-randomised clinical trial whose original aim was to evaluate the effect of hearing aids for hearing-impaired individuals with tinnitus. To achieve this, a range of patient-reported clinical measures, as well as functional magnetic resonance imaging (fMRI) were used to identify both clinical and neurophysiological markers of treatment-related change over a six-month period. Evidence for clinical impact of hearing aid provision in the management of tinnitus was examined. In study 1, tinnitus handicap was compared amongst two groups of chronic tinnitus patients; those opting for hearing aids (n=42) and age-matched controls who were not (n=14). A small statistically significant reduction in tinnitus handicap as measured by the Tinnitus Handicap Questionnaire was observed in the hearing aid group six months post-fitting compared to controls. However this was not clinically significant. Given the lack of evidence for strong clinical benefit, three further investigations were conducted to identify objective neurophysiological markers associated with the presence of tinnitus. These used baseline fMRI data (i.e. prior to any hearing aid provision) derived from the same age and hearing-matched groups (chronic tinnitus, n=12 and no tinnitus controls, n=11). Independent Component Analysis, region of interest analysis and Patel’s conditional dependence measures were used to investigate resting-state brain activity across the auditory network (study 2) and within the amygdala (study 3). Neither study found any between-group differences. Study 4 examined sound-evoked differences between groups by measuring the amygdala response to emotionally evocative soundscapes using a general linear model approach. Soundscapes rated as very pleasant or very unpleasant elicited stronger amygdala activity than neutral soundscapes (replicating a previous finding). However, activity in the tinnitus group was reduced compared to controls, contrary to our expectations. While results demonstrate that the objective quantification of tinnitus is possible, this nevertheless remains a challenging field. The investigation of resting-state and sound-evoked fMRI data derived from the same participant groups illustrates how neurophysiological markers of tinnitus may only become apparent given the right choice of experimental paradigm. The identification of a potential tinnitus-related biomarker in limbic, not auditory, brain regions leads us to speculate that functional imaging may be more sensitive to the emotional consequences of the tinnitus than the neural signature of the sound perception itself. Challenges and recommendations for future tinnitus research are identified

    Interrelationship between nutrients and chlorophyll-a in an urban stormwater lake during the ice-covered period

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    Urban stormwater lakes in cold regions are ice-covered for substantial parts of the winter. It has long been considered that the ice-covered period is the “dormant season,” during which ecological processes are inactive. However, little is known about this period due to the historical focus on the open-water season. Recent pioneering research on ice-covered natural lakes has suggested that some critical ecological processes play out on the ice. The objective of this study was to investigate the active processes in ice-covered stormwater lakes. Data collected during a two-year field measurement program at a stormwater lake located in Edmonton, Alberta, Canada were analyzed. The lake was covered by ice from November to mid-April of the following year. The mean value of chlorophyll-a during the ice-covered period was 22.09% of the mean value for the open-water season, suggesting that primary productivity under the ice can be important. Nitrogen and phosphorus were remarkably higher during the ice-covered period, while dissolved organic carbon showed little seasonal variation. Under ice-covered conditions, the total phosphorus was the major nutrient controlling the ratio of total nitrogen to total phosphorus, and a significant positive correlation existed between total phosphorus and chlorophyll-a when the ratio was smaller than 10. The results provide preliminary evidence of the critical nutrient processes in Stormwater Lake during the ice-covered period

    Does Chronic Tinnitus Alter the Emotional Response Function of the Amygdala?: A Sound-Evoked fMRI Study

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    Open access articleTinnitus is often associated with strong negative thoughts and emotions which can contribute to a distressing and chronic long-term condition. The amygdala, the “feeling and reacting” part of the brain, may play a key role in this process. Although implicated in several theoretical models of tinnitus, quantification of activity in the human amygdala has only been made possible more recently through neuroimaging methods such as functional magnetic resonance imaging (fMRI) but benefits from modified scanning parameters using a double-echo acquisition for improved BOLD sensitivity. This study thus examined the role of the amygdala in emotional sound processing in people with tinnitus using a novel double-echo imaging sequence for optimal detectability of subcortical activity. Our hypotheses were: (1) emotionally evocative sound clips rated as pleasant or unpleasant would elicit stronger amygdalar activation than sound clips rated as neutral, (2) people with tinnitus have greater amygdalar activation in response to emotionally evocative sounds (relative to neutral sounds) compared to controls. Methods: Twelve participants all with chronic, constant tinnitus took part. We also recruited 11 age and hearing-matched controls. Participants listened to a range of emotionally evocative sound clips; rated as pleasant, unpleasant or neutral. A region-of-interest analysis was chosen to test our a priori hypotheses. Results: Both groups displayed a robust and similar overall response to sounds vs. silence in the following ascending auditory pathways; inferior colliculus, medial geniculate body and the primary auditory cortex. In support of our first hypothesis, the amygdala's response to pleasant and unpleasant sound clips was significantly greater than neutral sounds. Opposing our second hypothesis, we found that the amygdala's overall response to pleasant and unpleasant sounds (compared to neutral sounds) was actually lower in the tinnitus group as compared to the controls. Conclusions: The “muted” amygdala activation observed in the tinnitus group could reflect an internal modification of emotional response perhaps as a result of successful habituation to emotionally negative sound. This interpretation would predict a heightened amygdala emotional response in individuals with a more clinically bothersome tinnitu

    Interrelationship Between Nutrients and Chlorophyll-a in an Urban Stormwater Lake During the Ice-covered Period

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    Urban stormwater lakes in cold regions are ice-covered for substantial parts of the winter. It has long been considered that the ice-covered period is the “dormant season,” during which ecological processes are inactive. However, little is known about this period due to the historical focus on the open-water season. Recent pioneering research on ice-covered natural lakes has suggested that some critical ecological processes play out on the ice. The objective of this study was to investigate the active processes in ice-covered stormwater lakes. Data collected during a two-year field measurement program at a stormwater lake located in Edmonton, Alberta, Canada were analyzed. The lake was covered by ice from November to mid-April of the following year. The mean value of chlorophyll-a during the ice-covered period was 22.09% of the mean value for the open-water season, suggesting that primary productivity under ice can be important. Nitrogen and phosphorus were remarkably higher during the ice-covered period, while dissolved organic carbon showed little seasonal variation. Under ice-covered conditions, the total phosphorus was the major nutrient controlling the ratio of total nitrogen to total phosphorus, and a significant positive correlation existed between total phosphorus and chlorophyll-a when the ratio was smaller than 10. The results provide preliminary evidence of the critical nutrient processes in the Stormwater Lake during the ice-covered period

    Induction of Alloantigen-specific Anergy in Human Peripheral Blood Mononuclear Cells by Alloantigen Stimulation with Co-stimulatory Signal Blockade

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    Allogeneic hematopoietic stem cell transplantation (AHSCT) offers the best chance of cure for many patients with congenital and acquired hematologic diseases. Unfortunately, transplantation of alloreactive donor T cells which recognize and damage healthy patient tissues can result in Graft-versus-Host Disease (GvHD)1. One challenge to successful AHSCT is the prevention of GvHD without associated impairment of the beneficial effects of donor T cells, particularly immune reconstitution and prevention of relapse. GvHD can be prevented by non-specific depletion of donor T cells from stem cell grafts or by administration of pharmacological immunosuppression. Unfortunately these approaches increase infection and disease relapse2-4. An alternative strategy is to selectively deplete alloreactive donor T cells after allostimulation by recipient antigen presenting cells (APC) before transplant. Early clinical trials of these allodepletion strategies improved immune reconstitution after HLA-mismatched HSCT without excess GvHD5, 6. However, some allodepletion techniques require specialized recipient APC production6, 7and some approaches may have off-target effects including depletion of donor pathogen-specific T cells8and CD4 T regulatory cells9.One alternative approach is the inactivation of alloreactive donor T cells via induction of alloantigen-specific hyporesponsiveness. This is achieved by stimulating donor cells with recipient APC while providing blockade of CD28-mediated co-stimulation signals10.This "alloanergization" approach reduces alloreactivity by 1-2 logs while preserving pathogen- and tumor-associated antigen T cell responses in vitro11. The strategy has been successfully employed in 2 completed and 1 ongoing clinical pilot studies in which alloanergized donor T cells were infused during or after HLA-mismatched HSCT resulting in rapid immune reconstitution, few infections and less severe acute and chronic GvHD than historical control recipients of unmanipulated HLA-mismatched transplantation12. Here we describe our current protocol for the generation of peripheral blood mononuclear cells (PBMC) which have been alloanergized to HLA-mismatched unrelated stimulator PBMC. Alloanergization is achieved by allostimulation in the presence of monoclonal antibodies to the ligands B7.1 and B7.1 to block CD28-mediated costimulation. This technique does not require the production of specialized stimulator APC and is simple to perform, requiring only a single and relatively brief ex vivo incubation step. As such, the approach can be easily standardized for clinical use to generate donor T cells with reduced alloreactivity but retaining pathogen-specific immunity for adoptive transfer in the setting of AHSCT to improve immune reconstitution without excessive GvHD
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