Space Weathering on Mercury: Laboratory Studies and Modelling

Mercury is one of the most mysterious objects in the Solar System. To date, Mercury has been visited only by the Mariner 10 spacecraft, which imaged less than half of the surface. The inner planet is now the target of two missions: NASA’s MESSENGER and the European Space Agency’s BepiColombo. One of the key measurement goals of both missions is global mapping of the surface composition. However, it is known from lunar research that regolith exposed to the space environment evolves in a way that obscures the mineralogical information otherwise derived from reflectance spectroscopy. This evolution process (space weathering), is the result of micrometeorite bombardment and solar wind sputtering, during which ferrous iron in lunar minerals is reduced to metallic iron. Such processes are also expected to operate on other airless bodies, including Mercury. This thesis focuses on the use of laboratory simulations of space weathering, with particular emphasis on Mercury. A pulsed laser facility was established, capable of simulating impacts into regolith analogues at varying temperatures. A variety of analytical techniques were then evaluated to quantify the amount of metallic iron produced and its size distribution; space weathering is critically dependent on both of these parameters. Nearly all of the optical and magnetic properties observed in lunar space weathering were also observed in laboratory analyses. Of the techniques used, measurements of magnetic susceptibility proved extremely useful. These were rapid and non-destructive measurements, and were diagnostic of the ferromagnetic iron produced during weathering. In addition, multi-frequency or temperature-dependent measurements could readily detect the very fine superparamagnetic particles that modified the reflectance spectra. Having demonstrated the importance of these measurements, the possibility of including a magnetic susceptibility sensor on future planetary landers was investigated; this would provide useful data constraining mineralogy and regolith maturity for very low mass and power resources

Slowmation: An Innovative Twenty-First Century Teaching and Learning Tool for Science and Mathematics Pre-service Teachers

Slowmation is a twenty-first century digital literacy educational tool. This teaching and learning tool has been incorporated as an assessment strategy in the curriculum area of science and mathematics with pre-service teachers (PSTs). This paper explores two themes: developing twenty-first century digital literacy skills and modelling best practice assessment tools. In the growing debate about the impact of multi-model representations, researchers such as Hoban and Nielsen, and Brown, Murcia and Hackling emphasise the development of conceptual understandings and semiotics. This paper focuses on PSTs’ experiences of and reflections on Slowmation as an educational tool. Data was collected from a cohort of final year PSTs who created, presented and reflected on their Slowmation process

New Knowledge from Old: In silico discovery of novel protein domains in Streptomyces coelicolor

BACKGROUND: Streptomyces coelicolor has long been considered a remarkable bacterium with a complex life-cycle, ubiquitous environmental distribution, linear chromosomes and plasmids, and a huge range of pharmaceutically useful secondary metabolites. Completion of the genome sequence demonstrated that this diversity carried through to the genetic level, with over 7000 genes identified. We sought to expand our understanding of this organism at the molecular level through identification and annotation of novel protein domains. Protein domains are the evolutionary conserved units from which proteins are formed. RESULTS: Two automated methods were employed to rapidly generate an optimised set of targets, which were subsequently analysed manually. A final set of 37 domains or structural repeats, represented 204 times in the genome, was developed. Using these families enabled us to correlate items of information from many different resources. Several immediately enhance our understanding both of S. coelicolor and also general bacterial molecular mechanisms, including cell wall biosynthesis regulation and streptomycete telomere maintenance. DISCUSSION: Delineation of protein domain families enables detailed analysis of protein function, as well as identification of likely regions or residues of particular interest. Hence this kind of prior approach can increase the rate of discovery in the laboratory. Furthermore we demonstrate that using this type of in silico method it is possible to fairly rapidly generate new biological information from previously uncorrelated data

Adventure Tourism and Adventure Sports Injury: the New Zealand experience

The primary aims of this study were to establish a client injury baseline for the New Zealand adventure tourism and adventure sport sector, and to examine patterns and trends in claims for injury during participation in adventure activities. Content analysis of narrative text data for compensated injuries occurring in a place for recreation and sport over a 12-month period produced over 15,000 cases involving adventure tourism and adventure sport. As found in previous studies in New Zealand, highest claims counts were observed for activities that are often undertaken independently, rather than commercially. Horse riding, tramping, surfing and mountain biking were found to have highest claims counts, while hang gliding/paragliding/parasailing and jet boating injuries had highest claims costs, suggesting greatest injury severity. Highest claims incidence was observed for horse riding, with female claimants over-represented for this activity. Younger male claimants comprised the largest proportion of adventure injuries, and falls were the most common injury mechanism

Towards sustainable tourism planning in New Zealand: monitoring local government planning under the Resource Management Act

In the light of the increasing pace and scale of tourism activity in New Zealand, the concept of sustainable tourism has become a key ingredient in the nation's tourism strategy. This paper explores sustainable tourism planning in New Zealand at the level of local government, and in particular, focuses on the implementation of the Resource Management Act 1991 (RMA) as a mechanism for achieving sustainable tourism. Using the findings of a survey of Regional Councils and Territorial Local Authorities, the paper explores public sector planning responses to tourism impacts and sustainability concerns in New Zealand. The paper extends the earlier work of Page and Thorn (1997; 2002), which identified major issues of concern at local council level with regard to tourism impacts and argued the need for a national vision for tourism to ensure that the RMA achieved its original goals. Since then, a national tourism strategy has been published and changes in legislation have further empowered local authorities to further progress the sustainability agenda. This paper examines these developments and the ensuing implications, concluding that significant progress has been made in developing tourism policies at the local level, but that a number of constraints and issues limit the development of New Zealand as a sustainable destination

Monitoring injury in the New Zealand adventure tourism sector: an operator survey

Background: Client safety is a major risk management concern for the commercial adventure tourism sector in New Zealand. This study built on previous exploratory analyses of New Zealand adventure tourism safety, including industry surveys conducted by these authors in 1999 and 2003. The aims of the study were to provide a continuation of injury monitoring across the sector through data collected from self-reported injury incidence by industry operators, and to compare findings with those from other primary and secondary research studies conducted by the authors. Method: A postal questionnaire was used to survey all identifiable New Zealand adventure tourism operators during 2006. The questionnaire asked respondents about their recorded client injury experience, perceptions of client injury risk factors, and safety management practices. Results: Some 21 adventure tourism activities were represented among the responding sample (n=127), with most operations being very small in terms of staff numbers, although responding operators catered for nearly one million clients in total annually. Highest ranked risk factors for client injury included clients not following instructions, level of client skill, ability and fitness, and changeable/unpredictable weather conditions. Highest client injury was reported for horse riding, eco-tourism and white water rafting sectors, although serious under-reporting of minor injuries was evidenced across the sector. Slips, trips and falls were the most frequently reported injury mechanism, while safety management measures were inconsistently applied across the sector. Conclusions: The industry should address reporting culture issues and safety management practices generally. Specifically, the industry should consider risk management that focuses on minor (e.g. falls) as well as catastrophic events

Psychosocial work environment, work engagement, and employee commitment: A moderated, mediation model

This paper contributes to the growing body of literature on the wellbeing of hospitality employees from a perspective of strategic human resource management. The role of high performance work systems (HPWS) in enhancing the affective commitment of hospitality employees is examined. The study found work engagement to mediate the relationships between HPWS, perceived organizational support, and affective commitment. Workplace bullying, a highly prevalent phenomenon in the hospitality sector, was found to mediate the relationship between HPWS and affective commitment, while psychosocial safety climate moderated this mediating impact. We will suggest the implications for managing psychosocial work hazards in hospitality organizations

A Synoptic Climatology of Derecho Producing Mesoscale Convective Systems in the North-Central Plains

Synoptic-scale environments favourable for producing derechos, or widespread convectively induced windstorms, in the North-Central Plains are examined with the goal of providing pattern-recognition:diagnosis techniques. Fifteen derechos were identified across the North-Central Plains region during 1986–1995. The synoptic environment at the initiation, mid-point and decay of each derecho was then evaluated using surface, upper-air and National Center for Atmospheric Research (NCAR):National Center for Environmental Prediction (NCEP) reanalysis datasets. Results suggest that the synoptic environment is critical in maintaining derecho producing mesoscale convective systems (DMCSs). The synoptic environment in place downstream of the MCS initiation region determines the movement and potential strength of the system. Circulation around surface low pressure increased the instability gradient and maximized leading edge convergence in the initiation region of nearly all events regardless of DMCS location or movement. Other commonalities in the environments of these events include the presence of a weak thermal boundary, high convective instability and a layer of dry low-to-mid-tropospheric air. Of the two corridors sampled, northeastward moving derechos tend to initiate east of synoptic-scale troughs, while southeastward moving derechos form on the northeast periphery of a synoptic-scale ridge. Other differences between these two DMCS events are also discussed

Bioinformatic identification of novel regulatory DNA sequence motifs in Streptomyces coelicolor

BACKGROUND: Streptomyces coelicolor is a bacterium with a vast repertoire of metabolic functions and complex systems of cellular development. Its genome sequence is rich in genes that encode regulatory proteins to control these processes in response to its changing environment. We wished to apply a recently published bioinformatic method for identifying novel regulatory sequence signals to gain new insights into regulation in S. coelicolor. RESULTS: The method involved production of position-specific weight matrices from alignments of over-represented words of DNA sequence. We generated 2497 weight matrices, each representing a candidate regulatory DNA sequence motif. We scanned the genome sequence of S. coelicolor against each of these matrices. A DNA sequence motif represented by one of the matrices was found preferentially in non-coding sequences immediately upstream of genes involved in polysaccharide degradation, including several that encode chitinases. This motif (TGGTCTAGACCA) was also found upstream of genes encoding components of the phosphoenolpyruvate phosphotransfer system (PTS). We hypothesise that this DNA sequence motif represents a regulatory element that is responsive to availability of carbon-sources. Other motifs of potential biological significance were found upstream of genes implicated in secondary metabolism (TTAGGTtAGgCTaACCTAA), sigma factors (TGACN(19)TGAC), DNA replication and repair (ttgtCAGTGN(13)TGGA), nucleotide conversions (CTACgcNCGTAG), and ArsR (TCAGN(12)TCAG). A motif found upstream of genes involved in chromosome replication (TGTCagtgcN(7)Tagg) was similar to a previously described motif found in UV-responsive promoters. CONCLUSIONS: We successfully applied a recently published in silico method to identify conserved sequence motifs in S. coelicolor that may be biologically significant as regulatory elements. Our data are broadly consistent with and further extend data from previously published studies. We invite experimental testing of our hypotheses in vitro and in vivo