Examining the neural correlates of choice behavior in a gambling task using steady state topography

The present study investigated the behavioral and neuropsychological characteristics of decision-making behavior during a gambling task as well as how these characteristics may relate to the Somatic Marker Hypothesis and the Frequency of Gain model. The applicability to intertemporal choice was also discussed. Patterns of card selection during a computerized interpretation of the Iowa Gambling Task were assessed for 10 men and 10 women. Steady State Topography was employed to assess cortical processing throughout this task. Results supported the hypothesis that patterns of card selection were in line with both theories. As hypothesized, these 2 patterns of card selection were also associated with distinct patterns of cortical activity, suggesting that intertemporal choice may involve the recruitment of right dorsolateral prefrontal cortex for somatic labeling, left fusiform gyrus for object representations, and the left dorsolateral prefrontal cortex for an analysis of the associated frequency of gain or loss. It is suggested that processes contributing to intertemporal choice may include inhibition of negatively valenced options, guiding decisions away from those options, as well as computations favoring frequently rewarded options.

γ-radiation-induced γH2AX formation occurs preferentially in actively transcribing euchromatic loci

The central dogma in radiation biology is that nuclear DNA is the critical target with respect to radiosensitivity. In accordance with the theoretical expectations, and in the absence of a conclusive model, the general consensus in the field has been to view chromatin as a homogeneous template for DNA damage and repair. This paradigm has been called into question by recent findings indicating a disparity in γ-irradiation-induced γH2AX foci formation in euchromatin and heterochromatin. Here, we have extended those studies and provide evidence that γH2AX foci form preferentially in actively transcribing euchromatin following γ-irradiation.

Visual rehabilitation in low-moderate keratoconus : intracorneal ring segment implantation followed by same-day topography-guided photorefractive keratectomy and collagen cross linking

AIM: To present the results of same-day topography-guided photorefractive keratectomy (TG-PRK) and corneal collagen crosslinking (CXL) after previous intrastromal corneal ring segment (ISCR) implantation for keratoconus. METHODS: An experimental clinical study on twenty-one eyes of 19 patients aged, 27.1±6.6 years (range: 19 – 43 years), with low to moderate keratoconus who were selected to undergo customized TG-PRK immediately followed by same-day CXL, 9 months after ISCR implantation in a university ophthalmology clinic. Refraction, uncorrected (UDVA) and corrected distance visual acuities (CDVA), keratometry (K) values, central corneal thickness (CCT) and coma were assessed 3 months after TG/PRK and CXL. RESULTS: After TG-PRK/CXL: the mean UDVA (logMAR) improved significantly from 0.66±0.41 to 0.20±0.25 (P<0.05); K flat value decreased from: 48.44±3.66 D to 43.71±1.95 D; K steep value decreased from 45.61±2.40 D to 41.56±2.05D; K average also decreased from 42.42±2.07 D to 47.00±2.66 D (P<0.05 for all). The mean sphere and cylinder decreased significantly post-surgery from, -3.10±2.99 D to -0.11±0.93 D and from, -3.68±1.53 to -1.11±0.75D respectively, while the CDVA, CCT and coma showed no significant changes. Compared to post-ISCR, significant reductions (P ˂ 0.05 or all) in all K-values, sphere and cylinder were observed after TG-PRK/CXL. CONCLUSION: Same-day combined topography-guided PRK and corneal crosslinking following placement of ICRS is a safe and potentially effective option in treating low-moderate keratoconus. It significantly improved all visual acuity, reduced keratometry, sphere and astigmatism, but caused no change in central corneal thickness and coma.

Photon beam dose distributions for patients with implanted temporary tissue expanders

This study examines the effects of temporary tissue expanders (TTEs) on the dose distributions of photon beams in breast cancer radiotherapy treatments. EBT2 radiochromic film and ion chamber measurements were taken to quantify the attenuation and backscatter effects of the inhomogeneity. Results illustrate that the internal magnetic port present in a tissue expander causes a dose reduction of approximately 25% in photon tangent fields immediately downstream of the implant. It was also shown that the silicone elastomer shell of the tissue expander reduced the dose to the target volume by as much as 8%. This work demonstrates the importance for an accurately modelled high-density implant in the treatment planning system for post-mastectomy breast cancer patients.

Characterisation of the half-field beam penumbra for a variety of blocking set-ups

Measurements of half-field beam penumbra were taken using EBT2 film for a variety of blocking techniques. It was shown that minimizing the SSD reduces the penumbra as the effects of beam divergence are diminished. The addition of a lead block directly on the surface provides optimal results with a 10-90% penumbra of 0.53 ± 0.02 cm. To resolve the uncertainties encountered in film measurements, future Monte Carlo measurements of halffield penumbras are to be conducted.

Magnetic resonance imaging: An accurate, radiation-free, alternative to computed tomography for the primary imaging and three-dimensional reconstruction of the bony orbit

Purpose: To determine the extent to which the accuracy of magnetic resonance imaging (MRI) based virtual 3-dimensional (3D) models of the intact orbit can approach that of the gold standard, computed tomography (CT) based models. The goal was to determine whether MRI is a viable alternative to CT scans in patients with isolated orbital fractures and penetrating eye injuries, pediatric patients, and patients requiring multiple scans in whom radiation exposure is ideally limited. Materials and Methods: Patients who presented with unilateral orbital fractures to the Royal Brisbane and Women’s Hospital from March 2011 to March 2012 were recruited to participate in this cross-sectional study. The primary predictor variable was the imaging technique (MRI vs CT). The outcome measurements were orbital volume (primary outcome) and geometric intraorbital surface deviations (secondary outcome)between the MRI- and CT-based 3D models. Results: Eleven subjects (9 male) were enrolled. The patients’ mean age was 30 years. On average, the MRI models underestimated the orbital volume of the CT models by 0.50 0.19 cm3 . The average intraorbital surface deviation between the MRI and CT models was 0.34 0.32 mm, with 78 2.7% of the surface within a tolerance of 0.5 mm. Conclusions: The volumetric differences of the MRI models are comparable to reported results from CT models. The intraorbital MRI surface deviations are smaller than the accepted tolerance for orbital surgical reconstructions. Therefore, the authors believe that MRI is an accurate radiation-free alternative to CT for the primary imaging and 3D reconstruction of the bony orbit. �

Sport development programmes for Indigenous Australians : innovation, inclusion and development, or a product of ‘white guilt’?

Under the legacy of neoliberalism, it is important to consider how the indigenous people, in this case of Australia, are to advance, develop and achieve some approximation of parity with broader societies in terms of health, educational outcomes and economic participation. In this paper, we explore the relationships between welfare dependency, individualism, responsibility, rights, liberty and the role of the state in the provision of Government-funded programmes of sport to Indigenous communities. We consider whether such programmes are a product of ‘white guilt’ and therefore encourage dependency and weaken the capacity for independence within communities and individuals, or whether programmes to increase rates of participation in sport are better viewed as good investments to bring about changes in physical activity as (albeit a small) part of a broader social policy aimed at reducing the gaps between Indigenous and non-Indigenous Australians in health, education and employment.

Imaginging the good Indigenous citizen : race war and the pathology of partiarchal white sovereignty

In June 2007, the Australian federal government sent military and policy into Indigenous communities in the Northern Territory on the premise that sexual abuse of children was rampant and a national crisis. This article draws on Foucault’s work on sovereignty and rights to argue that patriarchal white sovereignty as a regime of power deploys a discourse of pathology in the exercising of sovereign right to subjugate and discipline Indigenous people as good citizens.

A neuronal topography of visual and acoustic fear conditioning within the amygdala

The lateral amygdala (LA) receives information from auditory and visual sensory modalities, and uses this information to encode lasting memories that predict threat. One unresolved question about the amygdala is how multiple memories, derived from different sensory modalities, are organized at the level of neuronal ensembles. We previously showed that fear conditioning using an auditory conditioned stimulus (CS) was spatially allocated to a stable topography of neurons within the dorsolateral amygdala (LAd) (Bergstrom et al, 2011). Here, we asked how fear conditioning using a visual CS is topographically organized within the amygdala. To induce a lasting fear memory trace we paired either an auditory (2 khz, 55 dB, 20 s) or visual (1 Hz, 0.5 s on/0.5 s off, 35 lux, 20 s) CS with a mild foot shock unconditioned stimulus (0.6 mA, 0.5 s). To detect learning-induced plasticity in amygdala neurons, we used immunohistochemistry with an antibody for phosphorylated mitogen-activated protein kinase (pMAPK). Using a principal components analysis-based approach to extract and visualize spatial patterns, we uncovered two unique spatial patterns of activated neurons in the LA that were associated with auditory and visual fear conditioning. The first spatial pattern was specific to auditory cued fear conditioning and consisted of activated neurons topographically organized throughout the LAd and ventrolateral nuclei (LAvl) of the LA. The second spatial pattern overlapped for auditory and visual fear conditioning and was comprised of activated neurons located mainly within the LAvl. Overall, the density of pMAPK labeled cells throughout the LA was greatest in the auditory CS group, even though freezing in response to the visual and auditory CS was equivalent. There were no differences detected in the number of pMAPK activated neurons within the basal amygdala nuclei. Together, these results provide the first basic knowledge about the organizational structure of two different fear engrams within the amygdala and suggest they are dissociable at the level of neuronal ensembles within the LA

Clinical use of diodes and micro-chambers to obtain accurate small field output factor measurements

There have been substantial advances in small field dosimetry techniques and technologies, over the last decade, which have dramatically improved the achievable accuracy of small field dose measurements. This educational note aims to help radiation oncology medical physicists to apply some of these advances in clinical practice. The evaluation of a set of small field output factors (total scatter factors) is used to exemplify a detailed measurement and simulation procedure and as a basis for discussing the possible effects of simplifying that procedure. Field output factors were measured with an unshielded diode and a micro-ionisation chamber, at the centre of a set of square fields defined by a micro-multileaf collimator. Nominal field sizes investigated ranged from 6×6 to 98×98 mm2. Diode measurements in fields smaller than 30 mm across were corrected using response factors calculated using Monte Carlo simulations of the full diode geometry and daisy-chained to match micro-chamber measurements at intermediate field sizes. Diode measurements in fields smaller than 15 mm across were repeated twelve times over three separate measurement sessions, to evaluate the to evaluate the reproducibility of the radiation field size and its correspondence with the nominal field size. The five readings that contributed to each measurement on each day varied by up to 0.26%, for the “very small” fields smaller than 15 mm, and 0.18% for the fields larger than 15 mm. The diode response factors calculated for the unshielded diode agreed with previously published results, within 1.6%. The measured dimensions of the very small fields differed by up to 0.3 mm, across the different measurement sessions, contributing an uncertainty of up to 1.2% to the very small field output factors. The overall uncertainties in the field output factors were 1.8% for the very small fields and 1.1% for the fields larger than 15 mm across. Recommended steps for acquiring small field output factor measurements for use in radiotherapy treatment planning system beam configuration data are provided.

Practical implementation of species' recovery plans - Lessons from the White-backed Woodpecker Action Plan in Sweden

Successful biodiversity conservation requires safeguarding viable populations of species. To work with this challenge Sweden has introduced a concept of Action Plans, which focus on the recovery of one or more species; while keeping in mind the philosophy of addressing ecosystems in a more comprehensive way, following the umbrella concept. In this paper we investigate the implementationprocess of the ActionPlanfor one umbrella species, the White-backed Woodpecker (WBW) Dendrocopos leucotos. We describe the plan's organisation and goals, and investigate its implementation and accomplishment of particular targets, based on interviewing and surveying the key actors. The achievement of the targets in 2005-2008 was on average much lower than planned, explained partially by the lack of knowledge/data, experienced workers, and administrative flexibility. Surprisingly, the perceived importance of particular conservation measures, the investment priority accorded to them, the money available and various practical obstacles all failed to kg? explain the target levels achieved. However qualitative data from both the interviews and the survey highlight possible implementation obstacles: competing interests with other conservation actions and the level of engagement of particular implementing actors. Therefore we suggest that for successful implementation of recovery plans, there is aneed for initial and inclusive scoping prior to embarking on the plan, where not only issues like ecological knowledge and practical resources are considered, but also possible conflicts and synergies with other conservation actions. An adaptive approach with regular review of the conservation process is essential, particularly in the case of such complex action plans as the one for the WBW.