Defining the original extent and floristic composition of the naturally-treeless grasslands of the Liverpool Plains, North Western Slopes, New South Wales

A study was conducted on the Liverpool Plains (30o 43’–31o 44’S; 149o 40’–150o 41’E), North Western Slopes of NSW, to determine the original boundaries of the naturally-treeless grasslands, to determine reasons for the lack of woody vegetation on these areas, and to assess the status of Austrostipa aristiglumis (Plains Grass), a species that is today commonly dominant on the few remaining remnant grassland areas and is commonly assumed to characterise the original grassland community. The original tree line boundaries were reconstructed using NSW Lands Department survey portion plans and other historical records. The lack of woody vegetation was attributed primarily to a combination of fine-textured soil, climate and topography restricting the availability of water below the grass root zone, with waterlogging and deep soil cracking possibly playing minor roles. Published and anecdotal evidence and landholder experience indicate that the Austrostipa aristiglumis dominated remnants are probably a relatively recent anthropogenic feature, a consequence of post-settlement management practices. The pre-settlement grasslands appear to have been composed of a wide range of grasses, possibly dominated by species such as Themeda avenacea (Native Oatgrass) and Eulalia aurea (Silky Browntop), with a range of forbs occupying the interstitial spaces. Management implications are discussed

Social ties and the job search of recent immigrants

This article highlights a specific mechanism through which social networks help in job search. The authors characterize the strength of a network by its likelihood of providing a job offer. Using a theoretical model, they show that the difference between wages in jobs found using networks versus those found using formal channels decreases as the network becomes stronger. The authors verify this result for recent immigrants to Canada for whom a strong network is captured by the presence of a “close tie.” Furthermore, structural estimates confirm that the presence of a close tie operates by increasing the likelihood of generating a job offer from the network rather than by altering the network wage distribution.Accepted manuscrip

GTOSS: Generalized Tethered Object Simulation System

GTOSS represents a tether analysis complex which is described by addressing its family of modules. TOSS is a portable software subsystem specifically designed to be introduced into the environment of any existing vehicle dynamics simulation to add the capability of simulating multiple interacting objects (via multiple tethers). These objects may interact with each other as well as with the vehicle into whose environment TOSS is introduced. GTOSS is a stand alone tethered system analysis program, representing an example of TOSS having been married to a host simulation. RTOSS is the Results Data Base (RDB) subsystem designed to archive TOSS simulation results for future display processing. DTOSS is a display post processors designed to utilize the RDB. DTOSS extracts data from the RDB for multi-page printed time history displays. CTOSS is similar to DTOSS, but is designed to create ASCII plot files. The same time history data formats provided for DTOSS (for printing) are available via CTOSS for plotting. How these and other modules interact with each other is discussed

Joined-up food policy? The trials of governance, public policy and the food system

To address the policy malfunctions of the recent past and present, UK food policy needs to link policy areas that in the past have been dealt with in a disparate manner, and to draw on a new ecological public health approach. This will need a shift within the dominant trade liberalization–national economic competitiveness paradigm that currently informs UK food policy, and the international levels of the EU and the WTO trade rules, and grants the large corporate players in the food system a favoured place at the policy–making tables. The contradictions of the food system have wrought crises that have engendered widespread institutional change at all levels of governance. Recent institutional reforms to UK food policy, such as the FSA and DEFRA, reflect a bounded approach to policy integration. Initiatives seeking a more integrated approach to food policy problems, such as the Social Exclusion Unit’s access to shops report, and the Policy Commission on the Future of Food and Farming, can end up confined to a particular policy sector framed by particular interests—a process of “policy confinement”. However, the UK can learn from the experience of Norway and Finland who have found their own routes to a more joined–up approach to public health and a sustainable food supply by, for example, introducing a national food policy council to provide integrated policy advice. Also, at the local and community levels in the UK, policy alternatives are being advanced in an ad hoc fashion by local food initiatives. More structural–level interventions at the regional and local governance levels are also needed to address the social dimensions of a sustainable food suppl

A Laplace Transform Method for Molecular Mass Distribution Calculation from Rheometric Data

Polydisperse linear polymer melts can be microscopically described by the tube model and fractal reptation dynamics, while on the macroscopic side the generalized Maxwell model is capable of correctly displaying most of the rheological behavior. In this paper, a Laplace transform method is derived and different macroscopic starting points for molecular mass distribution calculation are compared to a classical light scattering evaluation. The underlying assumptions comprise the modern understanding on polymer dynamics in entangled systems but can be stated in a mathematically generalized way. The resulting method is very easy to use due to its mathematical structure and it is capable of calculating multimodal molecular mass distributions of linear polymer melts

Telescopes don't make catalogues!

Astronomical instruments make intensity measurements; any precise astronomical experiment ought to involve modeling those measurements. People make catalogues, but because a catalogue requires hard decisions about calibration and detection, no catalogue can contain all of the information in the raw pixels relevant to most scientific investigations. Here we advocate making catalogue-like data outputs that permit investigators to test hypotheses with almost the power of the original image pixels. The key is to provide users with approximations to likelihood tests against the raw image pixels. We advocate three options, in order of increasing difficulty: The first is to define catalogue entries and associated uncertainties such that the catalogue contains the parameters of an approximate description of the image-level likelihood function. The second is to produce a K-catalogue sampling in "catalogue space" that samples a posterior probability distribution of catalogues given the data. The third is to expose a web service or equivalent that can re-compute on demand the full image-level likelihood for any user-supplied catalogue.Comment: presented at ELSA 2010: Gaia, at the frontiers of astrometr