ESTIMATING POPULATION CHANGE AND DISPERSAL ACTIVITY OF SPIDERS IN AN AGRICULTURAL LANDSCAPE

The principal aims of this work were to investigate dispersal activity of spiders commonly found in agricultural crops, and to study the influence of both crop type and farm operations on spider assemblages and populations. Work was also conducted to develop and test an improved trapping method for samplmg aerially dispersing (ballooning) spiders. Objectives were to determine whether common farmland species exhibited species-specific differences in dispersal activity. Behavioural data from wind chamber studies were also related to field data to establish i f seasonality in dispersal was related to seasonal changes in dispersal motivation or variation in ground population densities. Ground population data were used to determine if field-scale differences in spider assemblage were related to crop type, and if crop-specific management was associated with variable impacts on spider populations. The improved trapping method ('stick and bottle' trap) was observed to increase catch sizes significantly (F(i,i8) = 30.11, P < .0001) compared to climbing-sticks with trapping adhesive. Total catch size over an eleven day period was 564 spiders. The use of an 'interception net' increased catch sizes threefold. Average loss of spiders from the traps was 9.1% ± 7.7% for daylight hours between 09:00 and 17:00. 5 The common Imyphiid spiders Engom atra, Oedothorax fuscus and Tenuiphantes tenuis were observed to display different patterns of dispersal over time. Patterns were similar for closely related species. Under wind chamber conditions, ballooning related activity in E atra comprised almost one third of total activity time yet was vitually absent in O. fuscus. Erigone atra was observed to balloon more frequently than O. fuscus m the field - it is suggested that factors influencing the tendency to balloon are different for these species. Ground populations related positively to balloonmg activity for Oedothorax spp. females and dentipalpis males. For other species the high efficiency of the trapping method may have reduced applicability to local ground populations Seasonal differences in ballooning motivation observed in E atra females in the wind chamber were likely related to differences in seasonal temperature affecting activity and not ballooning motivation Variation in spider assemblage composition was observed for fields under different management and crop production. Correspondence analysis suggested vegetation structure may mfluence the abundance of some species Set-aside was observed to have a higher proportion of non-lmyphiid species than other fields Oedothorax fuscus was dominant in almost all crops which could relate to its affinity for grass leys which predommate m the landscape. Harvesting m cereals and grass were seen to negatively impact spider populations with declmes of 96% and 83% observed respectively withm nme days of harvestmg Post harvest emigration was thought to contribute to these reductions Harvesting in maize however had a neglible impact on spider populations with relative high densities of adults overwmtering in maize stubbl

The Evolution of Male-Female Wages Differentials in Canadian Universities: 1970-2001

In this paper, we use a unique data set containing detailed information on all full-time teachers at Canadian universities over the period 1970 through 2001. The individual level data are collected by Statistics Canada from all universities in Canada and are used to analyze the evolution of male-female wage differentials of professors in Canadian universities. The long time series aspect of this data source along with the detailed administrative information allow us to provide a more complete and more accurate portrait of the wage gap than is available in most other studies. The results of a cohort-based analysis indicate that the male salary advantage among university faculty has declined for more recent birth cohorts. This has been driven not so much by an increase in the real salaries of female professors but from a cross cohort decline in the earnings of male professors and the fact that female professors have not experienced a similar cross cohort decline. Also important to note is the fact that the differences across cohorts appear to be permanent. There is no clear pattern of changes in these cohort differences with age.gender, earnings, Canada, professors, faculty

Aligning an undergraduate psychological medicine subject with the mental health needs of the local region

Background: The James Cook University (JCU) medical school recently revised its Year 2 human development and behaviour module to be more relevant and practical for students, and more aligned with the mental health priorities of the local region (north Queensland). This study reports medical students' level of preparedness conferred by the re-designed 'Psychological Medicine and Human Development' (PMHD) subject for their later 4-week, rural clinical placement in Year 2. Methods: Non-randomized, controlled 'naturalistic' study with pre- and post-intervention surveys. The patient mental health experiences of Year 2 students who went on clinical placement after undertaking the PMHD subject were compared to those who went on placement before undertaking PMHD. Results: A total of 209 JCU Year 2 medical students completed surveys from a possible 217 (response rate = 96%). Compared to students whom had not taken PMHD before going on placement, students going on placement after undertaking PMHD were significantly more likely to report: feeling comfortable discussing mental health issues with patients (p = 0.001); being prepared for mental health discussions with patients (p < 0.001); having an actual mental health discussion with a patient (p < 0.001); and, volunteering an opinion on the appropriateness of their supervising doctor's response (p < 0.001). Students reported subject content involving information and classroom instruction on assessing and interviewing patients for mental illness to be of most use. Conclusions: Providing medical students with psychological medicine information on locally prevalent mental health conditions plus practical classroom experiences in conducting mental state exams better prepares them for interacting with patients experiencing psychological distress. This novel methodology aligning formal teaching in a subject with an evaluation utilizing a proximate student placement to provide useful feedback on the curriculum content and assess the relevance of the material taught could be used to revise other content areas of a medical course to be more locally relevant and practically focused, and then to evaluate the success of this revision

Modelling of vorticity, sound and their interaction in two-dimensional superfluids

Vorticity in two-dimensional superfluids is subject to intense research efforts due to its role in quantum turbulence, dissipation and the BKT phase transition. Interaction of sound and vortices is of broad importance in Bose-Einstein condensates and superfluid helium [1-4]. However, both the modelling of the vortex flow field and of its interaction with sound are complicated hydrodynamic problems, with analytic solutions only available in special cases. In this work, we develop methods to compute both the vortex and sound flow fields in an arbitrary two-dimensional domain. Further, we analyse the dispersive interaction of vortices with sound modes in a two-dimensional superfluid and develop a model that quantifies this interaction for any vortex distribution on any two-dimensional bounded domain, possibly non-simply connected, exploiting analogies with fluid dynamics of an ideal gas and electrostatics. As an example application we use this technique to propose an experiment that should be able to unambiguously detect single circulation quanta in a helium thin film.Comment: 23 pages, 8 figure

The Impact of Cognitive Style Diversity on Implicit Learning in Teams

Organizations are increasingly looking for ways to reap the benefits of cognitive diversity for problem solving. A major unanswered question concerns the implications of cognitive diversity for longer-term outcomes such as team learning, with its broader effects on organizational learning and productivity. We study how cognitive style diversity in teams-or diversity in the way that team members encode, organize and process information-indirectly influences team learning through collective intelligence, or the general ability of a team to work together across a wide array of tasks. Synthesizing several perspectives, we predict and find that cognitive style diversity has a curvilinear-inverted U-shaped-relationship with collective intelligence. Collective intelligence is further positively related to the rate at which teams learn, and is a mechanism guiding the indirect relationship between cognitive style diversity and team learning. We test the predictions in 98 teams using ten rounds of the minimum-effort tacit coordination game. Overall, this research advances our understanding of the implications of cognitive diversity for organizations and why some teams demonstrate high levels of team learning in dynamic situations while others do not. Keywords: teams; team learning; implicit coordination; collective intelligence; cognitive diversityNational Science Foundation (U.S.) (Grant IIS-0963451

Numerical simulation of CO2 dispersion from punctures and ruptures of buried high-pressure dense phase CO2 pipelines with experimental validation

Carbon capture and storage (CCS) presents an option for significantly reducing the amount of carbon dioxide (CO2) released into the atmosphere and mitigating the effects of climate change. Pipelines are considered to be the most likely method for transporting captured CO2 and their safe operation is of paramount importance as their contents are likely to be in the region of several thousand tonnes and CO2 poses a number of concerns upon release due to its unusual physical properties. To this end, National Grid initiated the COOLTRANS (CO2 Liquid Pipeline Transportation) research programme to consider the pipeline transportation of high-pressure dense phase CO2. Part of this work involved the development of a mathematical model for predicting the dispersion of pure CO2 following the venting, puncture, or rupture, of such a transportation pipeline during normal operational conditions. In this paper, we describe the use of a computational fluid dynamic (CFD) tool that can be used to numerically simulate the near-field sonic dispersion from such releases, above and below ground. The model is shown to qualitatively and quantitatively reproduce observed experimental results. Validated flows at the top of the crater formed by below ground releases presented here for a range of scenarios provide the basis for developing robust source conditions for use in CFD studies of far-field dispersion, and for use with pragmatic quantified risk assessment (QRA) models