An in Situ Technique for Elemental Analysis of Lunar Surfaces

An in situ analytical technique that can remotely determine the elemental constituents of solids has been demonstrated. Laser-Induced Breakdown Spectroscopy (LIBS) is a form of atomic emission spectroscopy in which a powerful laser pulse is focused on a solid to generate a laser spark, or microplasma. Material in the plasma is vaporized, and the resulting atoms are excited to emit light. The light is spectrally resolved to identify the emitting species. LIBS is a simple technique that can be automated for inclusion aboard a remotely operated vehicle. Since only optical access to a sample is required, areas inaccessible to a rover can be analyzed remotely. A single laser spark both vaporizes and excites the sample so that near real-time analysis (a few minutes) is possible. This technique provides simultaneous multielement detection and has good sensitivity for many elements. LIBS also eliminates the need for sample retrieval and preparation preventing possible sample contamination. These qualities make the LIBS technique uniquely suited for use in the lunar environment

Adriamycin-loaded albumin-heparin conjugate microspheres for intraperitoneal chemotherapy

Adriamycin-loaded albumin-heparin conjugate microspheres (ADR-AHCMS) were evaluated as possible intraperitoneal (i.p.) delivery systems for site-specific cytotoxic action. The biocompatibility of the microspheres after intraperitoneal injection was tested first. 1 day after i.p. administration of empty as well as drug-loaded AHCMS to male Balb/c mice, only a moderate increase in i.p. neutrophils was measured. 3 days after injection neutrophil levels were comparable with the controls. No significant increases in the numbers of other cell types were observed, indicating an acute inflammatory response which can be considered to be mild. Antitumour efficacy was tested in an L1210 tumour-bearing mouse model and in a CC531 tumour-bearing rat model. The use of ADR-AHCMS leads to longer survival times of mice and improved tumour growth delay in rats, as compared with untreated controls and free drug treated animals. In both animal models higher adriamycin doses were initially tolerated if the drug was formulated in microspheres, although long-term adriamycin toxicity effects were evident in all treated groups. Doses and dosage schedules may be optimized to further reduce the toxic effects of the drug

A deep level set method for image segmentation

This paper proposes a novel image segmentation approachthat integrates fully convolutional networks (FCNs) with a level setmodel. Compared with a FCN, the integrated method can incorporatesmoothing and prior information to achieve an accurate segmentation.Furthermore, different than using the level set model as a post-processingtool, we integrate it into the training phase to fine-tune the FCN. Thisallows the use of unlabeled data during training in a semi-supervisedsetting. Using two types of medical imaging data (liver CT and left ven-tricle MRI data), we show that the integrated method achieves goodperformance even when little training data is available, outperformingthe FCN or the level set model alone

Takeovers, Governance and The Cross-Section of Returns

This paper considers the impact of the takeover channel on firm valuation. We use the idea that takeover activity responds to investor expectations of future rate of return and hence to state variable(s) related to the time variation in risk premia. Thus firms with higher exposure to takeovers, due to higher expectations of receiving a takeover premium, have a higher exposure to the state variable that dictates time variation in risk premia. Consequently, the difference in the returns between firms that differ in their takeover vulnerabilities can be used to used to proxy these state variables. To do so, we create a takeover-spread portfolio that buys firms with low cash-adjusted-leverage (cheaper targets) and shorts firms with high cash-adjusted-leverage and show that such a portfolio generates annualized abnormal returns of up to 11.20% between 1980 and 2003. Also, abnormal returns associated with governance-spread portfolios (Gompers, Ishii and Metrick, 2003 and Cremers and Nair, 2004) decrease significantly once the asset pricing model includes this ’cash-adjusted-leverage’ factor. Finally, we propose a new ‘takeover’ factor to proxy for the risk due to changes in these risk-premia related state variables, which is shown to be important in explaining cross-sectional differences in equity returns. The paper shows why investors require a higher rate of return on firms exposed to takeovers and yet value them higher than firms protected from takeovers

Assessment of image quality and dose calculation accuracy on kV CBCT, MV CBCT, and MV CT images for urgent palliative radiotherapy treatments.

A clinical workflow was developed for urgent palliative radiotherapy treatments that integrates patient simulation, planning, quality assurance, and treatment in one 30-minute session. This has been successfully tested and implemented clinically on a linac with MV CBCT capabilities. To make this approach available to all clinics equipped with common imaging systems, dose calculation accuracy based on treatment sites was assessed for other imaging units. We evaluated the feasibility of palliative treatment planning using on-board imaging with respect to image quality and technical challenges. The purpose was to test multiple systems using their commercial setup, disregarding any additional in-house development. kV CT, kV CBCT, MV CBCT, and MV CT images of water and anthropomorphic phantoms were acquired on five different imaging units (Philips MX8000 CT Scanner, and Varian TrueBeam, Elekta VersaHD, Siemens Artiste, and Accuray Tomotherapy linacs). Image quality (noise, contrast, uniformity, spatial resolution) was evaluated and compared across all machines. Using individual image value to density calibrations, dose calculation accuracies for simple treatment plans were assessed for the same phantom images. Finally, image artifacts on clinical patient images were evaluated and compared among the machines. Image contrast to visualize bony anatomy was sufficient on all machines. Despite a high noise level and low contrast, MV CT images provided the most accurate treatment plans relative to kV CT-based planning. Spatial resolution was poorest for MV CBCT, but did not limit the visualization of small anatomical structures. A comparison of treatment plans showed that monitor units calculated based on a prescription point were within 5% difference relative to kV CT-based plans for all machines and all studied treatment sites (brain, neck, and pelvis). Local dose differences >5% were found near the phantom edges. The gamma index for 3%/3 mm criteria was ≥95% in most cases. Best dose calculation results were obtained when the treatment isocenter was near the image isocenter for all machines. A large field of view and immediate image export to the treatment planning system were essential for a smooth workflow and were not provided on all devices. Based on this phantom study, image quality of the studied kV CBCT, MV CBCT, and MV CT on-board imaging devices was sufficient for treatment planning in all tested cases. Treatment plans provided dose calculation accuracies within an acceptable range for simple, urgently planned palliative treatments. However, dose calculation accuracy was compromised towards the edges of an image. Feasibility for clinical implementation should be assessed separately and may be complicated by machine specific features. Image artifacts in patient images and the effect on dose calculation accuracy should be assessed in a separate, machine-specific study. PACS number(s): 87.55.D-, 87.57.C-, 87.57.Q

Learning to be literate in Aboriginal communities: The significance of text

In Australia the model of reading outlined in many syllabus documents and the Australian National Curriculum: English acknowledges that reading is a socio-cultural practice and that both the contexts of culture and situation define the meanings individual students will make when approaching a given text. The difficulty of any given text therefore varies for individual students, depending not only on their skills but their understandings about the cultural context and the situation in which they encounter the text. Many students might find school a “natural setting” in which to learn, and may therefore be acquiring knowledge at school because their understandings about language and education predispose them to learning in such an environment. Many Aboriginal children however, do not find their understandings of language and culture reflected in the school environment. The purpose of this multi-site case study was to better understand the significance of authentic local texts in the teaching of reading in four Aboriginal communities. The project that formed the basis of this case study, was the development of the One Mob books community writers kit, aimed at creating local books in these four communities and involving teachers, community workers and members of the local community. The role of story for Aboriginal children and the importance of the local community in becoming literate were central features of the research findings. Under achievement in literacy was identified as a barrier to educational success in each context. Sharing local stories and language provided the Aboriginal communities with a positive way to interact with the school community, to engage their own and other children in their history and culture and to support their children’s literacy learning

Emoto - visualising the online response to London 2012.

In recent years we have moved from data scarcity to data abundance. As a response, a variety of methods have been adopted in art, design, business, science and government to understand and communicate meaning in data through visual form. emoto (emoto2012.org) is one such project, it visualised the online audience response to a major global event, the London 2012 Olympic and Paralympic Games. emoto set out to both give expression to and augment online social phenomena, that are emergent and only recently made possible by access to huge real-time data streams. This report charts the development and release of the project, and positions it in relation to current debates on data and visualisation, for example, around the bias and accessibility of the data, and how knowledge practices are changing in an era of so-called 'big data.