North polar stratigraphy and the paleo-erg of Mars

An accurate self-consistent way of coregistering the imaging and topographic data sets of the Mars Global Surveyor mission was developed and used to begin a stratigraphic analysis of the northern polar region. A distinct change in the layering style exists at a definite stratigraphic horizon near the base of the north polar layered deposits. Occurrences of the contact between two distinct layered units can be mapped hundreds of kilometers apart at nearly the same Mars Orbiter Laser Altimeter (MOLA) elevation. The lower layered unit has a consistent association with sand dunes, leading to the conclusion that it is an eroding sand-rich deposit that predates most of the overlying north polar layered deposits, which exhibits the expected features of a dust-ice mixture. These results suggest that an areally extensive erg was in existence before the present ice cap and that the present circumpolar erg is likely composed of material reworked from this older deposit. The volume of this lower unit is estimated to be on the order of 10^5 km^3. The presence of this deposit implies that there existed a period in Mars' history when there was no icy polar cap. A dramatic climatic change leading to the deposition of the upper layered (icy) unit in the present-day polar layered deposits represents a major event in Mars' history. However, owing to uncertainties in the mechanics of layered deposits formation, such an event cannot be dated at this time

Track: Teaching Political Theory and Theories

The 2011 Teaching Political Theory and Theories track drew scholars from Europe and the United States and featured work from political scientists representing the four major subfields. While analyzing the nine papers presented, participants articulated a range of perspectives on questions of pedagogy and the relationship between political theory and political science; indeed, the variety of perspectives confirmed the ongoing contestability of many central concepts in both the scholarship of teaching and learning (SOTAL) and the discipline of political science.Whether discussing ways to develop assignments for undergraduate research projects on the Tea Party or how to employ insights from deliberative democratic theory to assess the role of education in addressing racial violence in the United States, participants confronted important questions regarding the role of theory in the discipline, the broadening of undergraduate and graduate teaching strategies, and assessment of the effectiveness of alternative teaching strategies

Crater population and resurfacing of the Martian north polar layered deposits

Present-day accumulation in the north polar layered deposits (NPLD) is thought to occur via deposition on the north polar residual cap. Understanding current mass balance in relation to current climate would provide insight into the climatic record of the NPLD. To constrain processes and rates of NPLD resurfacing, a search for craters was conducted using images from the Mars Reconnaissance Orbiter Context Camera. One hundred thirty craters have been identified on the NPLD, 95 of which are located within a region defined to represent recent accumulation. High Resolution Imaging Science Experiment images of craters in this region reveal a morphological sequence of crater degradation that provides a qualitative understanding of processes involved in crater removal. A classification system for these craters was developed based on the amount of apparent degradation and infilling and where possible depth/diameter ratios were determined. The temporal and spatial distribution of crater degradation is interpreted to be close to uniform. Through comparison of the size-frequency distribution of these craters with the expected production function, the craters are interpreted to be an equilibrium population with a crater of diameter D meters having a lifetime of ~30.75D^(1.14) years. Accumulation rates within these craters are estimated at 7.2D^(−0.14) mm/yr, which corresponds to values of ~3–4 mm/yr and are much higher than rates thought to apply to the surrounding flat terrain. The current crater population is estimated to have accumulated in the last ~20 kyr or less

Strategically using public housing assets could transform our middle suburbs

‘Greyfields’ in the Australian context have been defined as those ageing but occupied tracts of inner and middle ring suburbia that are physically, technologically and environmentally failing. The research sought to test the potential of an innovative design based approach to create coordinated precincts in these suburbs involving the coordinated redevelopment of multiple, non-contiguous public housing lots (rather than relying on the ‘default’ option of incremental market based development of in-fill housing and piecemeal selling off of public housing properties). Recent public housing investments (under the Social Housing Initiative) were typically planned with job creation in mind rather than innovative housing outcomes, but innovations were still apparent. Innovations were generally simple such as improvements to parking arrangements and interfaces of private dwellings with common areas and public spaces and arrangements for tenancy mix and social diversity. Innovations were often more apparent when governments partnered with Community Housing Organisations who could access alternative land and funding sources, offer design and delivery expertise and facilitate mixed tenancy outcomes. Innovation also was more likely when there was a ‘champion’ for design quality, relaxation of selected planning controls, and project alignment with existing urban renewal strategies. The Department of Human Services (Victorian Government) was found to have existing housing assets in sufficient number (more than 6500 DHS properties) in well-located areas of Melbourne’s middle suburbs that were clustered in ways broadly suitable for coordinated precinct redevelopment. Preliminary investigations suggest the same in Sydney and Brisbane. The coordinated precinct approach could offer an effective model for redeveloping dispersed public housing assets. Integrated redevelopment can achieve substantial increases in dwelling yield—design scenarios developed in this study delivered two to four times the number of dwellings when compared to business-as-usual dual occupancy outcomes. A precinct design approach is potentially more efficient because it allows for non-uniform, flexible siting of higher density buildings, effective program mixes, efficient parking arrangements and a variety of households and tenure types to be accommodated across a neighbourhood. Preliminary discussions with key stakeholders—municipal authorities, community housing organisations and local community members—showed real interest in the benefits of a coordinated precinct-based development approach. - See more at: http://www.ahuri.edu.au/publications/projects/p52012#sthash.wTtz4itu.dpu

Co-expression and promoter content analyses assign a role in biotic and abiotic stress responses to plant natriuretic peptides

<p>Abstract</p> <p>Background</p> <p>Plant natriuretic peptides (PNPs) are a class of systemically mobile molecules distantly related to expansins. While several physiological responses to PNPs have been reported, their biological role has remained elusive. Here we use a combination of expression correlation analysis, meta-analysis of gene expression profiles in response to specific stimuli and in selected mutants, and promoter content analysis to infer the biological role of the <it>Arabidopsis thaliana </it>PNP, AtPNP-A.</p> <p>Results</p> <p>A gene ontology analysis of <it>AtPNP-A </it>and the 25 most expression correlated genes revealed a significant over representation of genes annotated as part of the systemic acquired resistance (SAR) pathway. Transcription of these genes is strongly induced in response to salicylic acid (SA) and its functional synthetic analogue benzothiadiazole S-methylester (BTH), a number of biotic and abiotic stresses including many SA-mediated SAR-inducing conditions, as well as in the constitutive SAR expressing mutants <it>cpr5 </it>and <it>mpk4 </it>which have elevated SA levels. Furthermore, the expression of <it>AtPNP-A </it>was determined to be significantly correlated with the SAR annotated transcription factor, <it>WRKY 70</it>, and the promoters of <it>AtPNP-A </it>and the correlated genes contain an enrichment in the core WRKY binding W-box <it>cis</it>-elements. In constitutively expressing <it>WRKY 70 </it>lines the expression of <it>AtPNP-A </it>and the correlated genes, including the SAR marker genes, <it>PR-2 </it>and <it>PR-5</it>, were determined to be strongly induced.</p> <p>Conclusion</p> <p>The co-expression analyses, both in wild type and mutants, provides compelling evidence that suggests <it>AtPNP-A </it>may function as a component of plant defence responses and SAR in particular. The presented evidence also suggests that the expression of <it>AtPNP-A </it>is controlled by WRKY transcription factors and WRKY 70 in particular. <it>AtPNP-A </it>shares many characteristics with PR proteins in that its transcription is strongly induced in response to pathogen challenges, it contains an N-terminal signalling peptide and is secreted into the extracellular space and along with PR-1, PR-2 and PR-5 proteins it has been isolated from the Arabidopsis apoplast. Based on these findings we suggest that <it>AtPNP-A </it>could be classified as a newly identified PR protein.</p

Search Engine Optimisation in UK news production

This is an Author's Accepted Manuscript of an article published in Journalism Practice, 5(4), 462 - 477, 2011, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/17512786.2010.551020.This paper represents an exploratory study into an emerging culture in UK online newsrooms—the practice of Search Engine Optimisation (SEO), which assesses its impact on news production. Comprising a short-term participant observational case study at a national online news publisher, and a series of semi-structured, in-depth interviews with SEO professionals at three further UK media organisations, the author sets out to establish how SEO is operationalised in the newsroom, and what consequences these practices have for online news production. SEO practice is found to be varied and application is not universal. Not all UK news organisations are making the most of SEO even though some publishers take a highly sophisticated approach. Efforts are constrained by time, resources and management support, as well as off-page technical issues. SEO policy is found, in some cases, to inform editorial policy, but there is resistance to the principal of SEO driving decision-making. Several themes are established which call for further research

South Polar Layered Deposits of Mars: The cratering record

Data from the Mars Orbiter Laser Altimeter (MOLA) and Mars Orbiter Camera (MOC) instruments aboard the Mars Global Surveyor (MGS) were used in a detailed search of a selected part of the South Polar Layered Deposits (SPLD) for impact craters. Impact craters with diameters from 0.8 to 5 km were identified from a MOLA-derived shaded relief map and were primarily validated using individual MOLA tracks and, in select cases, MOC narrow angle images. The resultant crater population determined in this study is at least four times the density of the crater population previously recognized. From these new statistics, we estimate the mean apparent surface age of the SPLD to be 30–100 Ma, depending on the established production model isochrons used. All of these craters are considerably shallower than other Martian craters in the same diameter range. We attribute this shallowness to be the cause of the lower detection rates of previous studies. There is a correlation between crater depth and rim height, which suggests that both erosion and infilling have affected the crater forms. A similar study of the north polar layered deposits uncovered no craters in this diameter range. A limited population of craters smaller than 800 m was uncovered in higher-resolution MOC narrow angle images. These do not appear to have been degraded to the same degree. This separate population implies a surface exposure age of only 100,000 years and perhaps indicates an event that erased all small craters and degraded and infilled the larger ones