Radiation leukaemogenesis: is virus really necessary?

Generalized lymphosarcomatosis (leukaemia) of non-thymic type occurs in mice bearing 90Sr or 239Pu or 226Ra. Tumours passaged from such mice have been tested for tumour-associated transplantation antigens that could provoke a protective immunity which would be expected if such antigens were determined by virus activated by the irradiation. Sub-threshold doses of living syngeneic tumour, large doses of living allogeneic tumour and large doses of killed syngeneic tumour were without protective effect. This suggests that viruses observed electron micrographically in such tumours are passengers and not causative

Drilled versus topdressed superphosphate for cereal production

CEREAL growers in Australia usually use a drill or combine to apply their seed and superphosphate in one operation. However, during the last few years, there has been a rapid increase in the amount of super broadcast bafore seeding

Suitability of the dorsal column nuclei for a neural prosthesis: functional considerations

The brainstem dorsal column nuclei (DCN) may be an ideal target for a future neural prosthesis to restore somatosensation in tetraplegic patients. We aimed to investigate the functional and structural characteristics of the DCN, with the overarching goal of determining their suitability as a somatosensory neural prosthetic target. First, we review the neuroanatomy of the DCN and surrounding nuclei, including the cuneate, gracile, external cuneate, X, and Z nuclei, which together comprise the DCN-complex. We reveal that the DCN are not organised to only process and relay tactile information, as is commonly thought, but instead are a complex sensorimotor integration and distribution hub, with diverse projection targets throughout the hindbrain and midbrain. Next, we sought to show that somatosensory signals arriving in the DCN are reproducible, and that they carry decodable information about the location and quality of somatosensory stimuli, which we propose are necessary conditions for a potential somatosensory neural prosthetic target. We record somatosensory-evoked signals from various locations across the surface of the DCN in 8-week-old anaesthetised male Wistar rats. We characterised somatosensory-evoked DCN surface signals and demonstrated that they have robust and reproducible high-frequency and low-frequency features within and across animals. Using a machine-learning approach, we developed a metric for evaluating the relevance of machine-learning inputs to target outputs, which we coined feature-learnability. Using feature-learnability allowed us to determine the DCN signal features that were most relevant to peripheral somatosensory events, which facilitated very high accuracy prediction of the location and quality of somatosensory events, from small numbers of features. This thesis supports the DCN as a potential somatosensory neural prosthetic target by: i) showing DCN connectivity with sensorimotor targets essential for movement modulation in conscious and non-conscious neural pathways; ii) determining DCN signal features that are most relevant to peripheral tactile and proprioceptive events. New knowledge about the most relevant DCN signal features may inform the development of biomimetic stimulus patterns designed to artificially activate the DCN in future neural prosthetic devices for restoring somatosensory feedback

Integrated Late Eocene-Oligocene Stratigraphy of the Alabama Coastal Plain: Correlation of Hiatuses and Stratal Surfaces to Glacioeustatic Lowerings

We integrated strontium and oxygen isotopic, biostratigraphic, and magnetostratigraphic studies of two upper Eocene-Oligocene boreholes drilled near Bay Minette and St. Stephens Quarry (SSQ), Alabama. Continuous coring provided fresh, unweathered material for magnetostratigraphic studies, minimizing problems reported from nearby outcrops. Difficulties with each technique were encountered because of diagenesis, absence of marker fossils, and the presence of unconformities; however, by integrating results from isotopic stratigraphy, biostratigraphy, and magnetostratigraphy, we correlated these relatively shallow-water deposits to the geomagnetic polarity time scale (GPTS). At the SSQ borehole, the upper Eocene to lower Oligocene section is apparently complete within our stratigraphic resolution (0.2-0.5 m.y.), allowing us to estimate the ages of several stratal surfaces. Late Eocene Sr isotope age estimates are as expected at the SSQ borehole, but Oligocene ages are ~1 m.y. older than expected due to diagenesis. At the Bay Minette borehole, a latest Eocene-earliest Oligocene and a late early Oligocene hiatus were detected. We correlate these two hiatuses and stratal surfaces at SSQ with global δ^18O increases inferred to represent glacioeustatic lowerings and with evidence for hiatuses on other continental margins: (1) a distinct disconformity at the base of the Chickasawhay Limestone at both boreholes and a hiatus at Bay Minette correlates with a global δ^18O increase; we revise the age of this surface (equivalent to the TB 1.1 sequence boundary) making it ~2 m.y. older than previously reported; and (2) a surface at the top of the Shubuta Member (lowermost Oligocene) has been interpreted both as a condensed section and a disconformity; this surface at SSQ and a hiatus at Bay Minette correlate with a sharp global δ^18O increase and with hiatuses on the New Jersey and Irish margins. The timing of the hiatuses and stratal surfaces correlates with the inflection of the δ^18O increases and not with the maximum values, supporting models that indicate that unconformities form during the maximum rates of sea level fall

Emerging Practices in Community Development Agreements

A Community Development Agreement or CDA can be a vital mechanism for ensuring that local communities benefit from large-scale investment projects, such as mines or forestry concessions. In formalizing agreements between an investor and a project-affected community, CDAs set out how the benefits of an investment project will be shared with local communities. In some countries CDAs are required by domestic legislation; in others, they are entered into voluntarily. The most effective CDAs are also adapted to the local context, meaning that no single model agreement or process will be appropriate in every situation. Nonetheless, leading practices are emerging which can be required by governments or voluntarily adopted by companies and communities. This briefing note reviews existing research, as well as available agreements from the extractive sector in Australia, Canada, Laos, Papua New Guinea, Ghana and Greenland, to highlight these leading practices