Fitting models of multiple hypotheses to partial population data: investigating the causes of cycles in red grouse

There are two postulated causes for the observed periodic fluctuations (cycles) in red grouse (Lagopus lagopus scoticus). The first involves interaction with the parasitic nematode Trichostrongylus tenuis. The second invokes delayed regulation through the effect of male aggressiveness on territoriality. Empirical evidence exists to support both hypotheses, and each hypothesis has been modeled deterministically. However, little effort has gone into looking at the combined effects of the two mechanisms or formally fitting the corresponding models to field data. Here we present a model for red grouse dynamics that includes both parasites and territoriality. To explore the single and combined hypotheses, we specify three versions of this model and fit them to data using Bayesian state‐space modeling, a method that allows statistical inference to be performed on mechanistic models such as ours. Output from the three models is then examined to determine their goodness of fit and the biological plausibility of the parameter values required by each to fit the population data. While all three models are capable of emulating the observed cyclic dynamics, only the model including both aggression and parasites does so under consistently realistic parameter values, providing theoretical support for the idea that both mechanisms shape red grouse cycles

The effects of budget emphasis, budgetary participation, trust and organisational commitment on job related tension and propensity to create slack : Empirical evidence from Norway

Results of early studies (eg. Hopwood, 1972; Otley, 1978) on the effects of supervisory styles on subordinates’ job related tension have been contradictory. Subsequent studies using the contingency model to resolve these conflicting results have identified budgetary participation (Brownell, 1982a) and trust (Ross, 1994) as important moderating variables. With respect to participation, a number of prior studies found that a compatible combination of high budget emphasis and high participation was associated with better behavioural outcomes (eg. lower job related tension), than other combinations of budget emphasis and participation. Yet there has been relatively little research to investigate why this particular combination of budget emphasis and participation is associated with better behavioural outcomes. This thesis therefore investigates a number of important issues. First, it investigates whether different combinations of budget emphasis and participation affect subordinates\u27 propensity to create slack and job related tension differently. Second, it examines whether a high budget emphasis-high participation combination results in lower subordinates\u27 propensity to create slack and lower job related tension than a low budget emphasis-high participation combination. Third, it investigates the reasons why a high budget emphasis-high participation combination leads to lower propensity to create slack and lower job related tension. The interaction between budget emphasis and participation was dealt with by testing a model on supervisory styles in a high participatory environment. Norway was hypothesised to have a high participatory environment because of its high power distance culture and its highly centralised and formalised industrial relations systems which emphasise democratic work environment. Moreover, its highly homogeneous population and society are likely to result in a small diversity within its national culture, which in turn, leads to a smaller range of participation. Hence participation in Norway is expected to be not only high, but also widespread. This means that a high budget emphasis situation in Norway is similar to a high budget emphasis and high participation combination, whilst a low budget emphasis situation in Norway is similar to a low budget emphasis-high participation combination. This allows a high budget emphasis-high participation (Norway) situation to be compared with a low budget emphasis-high participation (Norway) situation. Consequently, a high budget emphasis situation in Norway, which is similar to a high budget emphasis and high participation situation, is therefore expected to be associated with lower job related tension than a low budget emphasis in Norway. In order to investigate the reason why a high budget emphasis-high participation combination promotes lower propensity to create slack and job related tension, path analytical models, which investigate the intervening effects of participation, trust and organisational commitment on the relationship between budget emphasis and propensity to create slack/job related tension, were developed. Testing these models in Norway permits two issues to be investigated. These are: (i) the interaction between budget emphasis and participation affecting propensity to create slack/job related tension, and (ii) the intervening effects of participation, trust and organisational commitment on the relationship between budget emphasis and propensity to create slack/job related tension. The results support the expectation that Norwegian managers generally enjoy very high level of budgetary participation. Second, they also support the expected significant negative relationship between budget emphasis and job related tension. Third, a high budget emphasis situation in Norway (high participatory) was found to have only a small and insignificant direct effect of job related tension. Instead, there is a strong indirect effect through trust. Based on these results, it is possible to conclude that a high budget emphasis and high participation combination will lead to lower job related tension. The reason for this is partly because this combination promotes higher trust between the subordinates and their superior. Trust, in turn, leads to lower subordinates\u27 job related tension. These results provide valuable insights which help to explain why a compatible combination of high budget emphasis and high participation, found by a number of prior studies with the contingency model, can lead to better behavioural outcomes than other combinations of budget emphasis and participation

Chlorinated organic contaminants in breast milk of New Zealand women.

Breast milk samples from 38 women in New Zealand were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) as part of a World Health Organization collaborative study of breast-milk contaminants. The women were recruited from two urban areas (Auckland and Christchurch) and two rural areas (Northland and North Canterbury) in the North and South Islands of New Zealand. The best predictor of contaminant concentrations in breast milk was found to be the age of the mother. Regional differences were found for hexachlorobenzene, dieldrin, and pp-DDE, reflecting historical use patterns. Urban-rural differences were found for several PCBs, PCDDs, and PCDFs when contaminant concentrations were calculated on a whole-milk basis. However, these differences could be attributed to variation in breast-milk fat concentrations between urban and rural mothers. Urban mothers had about 50% more breast-milk fat than rural mothers. Evidence suggests that breast-milk consumption by babies is regulated by caloric intake. Almost all of the caloric content of milk is in the fat fraction. This suggests that breast-milk contaminant levels calculated on a whole-milk basis do not necessarily reflect the relative levels of exposure of infants to these contaminants. However, the factors that influence breast-milk fat concentration deserve further study

Mixture models for distance sampling detection functions

Funding: EPSRC DTGWe present a new class of models for the detection function in distance sampling surveys of wildlife populations, based on finite mixtures of simple parametric key functions such as the half-normal. The models share many of the features of the widely-used “key function plus series adjustment” (K+A) formulation: they are flexible, produce plausible shapes with a small number of parameters, allow incorporation of covariates in addition to distance and can be fitted using maximum likelihood. One important advantage over the K+A approach is that the mixtures are automatically monotonic non-increasing and non-negative, so constrained optimization is not required to ensure distance sampling assumptions are honoured. We compare the mixture formulation to the K+A approach using simulations to evaluate its applicability in a wide set of challenging situations. We also re-analyze four previously problematic real-world case studies. We find mixtures outperform K+A methods in many cases, particularly spiked line transect data (i.e., where detectability drops rapidly at small distances) and larger sample sizes. We recommend that current standard model selection methods for distance sampling detection functions are extended to include mixture models in the candidate set.Publisher PDFPeer reviewe

Software requirements: Guidance and control software development specification

The software requirements for an implementation of Guidance and Control Software (GCS) are specified. The purpose of the GCS is to provide guidance and engine control to a planetary landing vehicle during its terminal descent onto a planetary surface and to communicate sensory information about that vehicle and its descent to some receiving device. The specification was developed using the structured analysis for real time system specification methodology by Hatley and Pirbhai and was based on a simulation program used to study the probability of success of the 1976 Viking Lander missions to Mars. Three versions of GCS are being generated for use in software error studies

Glittering in the dark: Memory, culture, and critique in light of the history of information

An ethical and human-centered approach to Information Science requires rigorous, historically-informed analysis of both the resources that inform this discipline and the cultural role it inhabits. This session will present and discuss significant recent developments in the history and foundations of the field. ASIST has formally established a new volunteer administrative position of ASIST Curator. Kathryn La Barre, the newly-appointed Curator, will describe the role and responsibilities of this position and assess the state of Information Science history in relation to the conference themes. In two complementary reports: Michael Buckland will examine theoretical accounts of the materials made use of in Information Science; and Sachi Arafat will explain why Information Retrieval and Information Science should be integrated and rethought as a science of technology-mediated experience, and how this new kind of science relates to the pre-modern memory arts tradition

Prioritisation of companion dog welfare issues using expert consensus

Resources for tackling animal welfare issues are often limited. Obtaining a consensus of expert opinion on the most pressing issues to address is a valuable approach to try to ensure that resources are wisely spent. In this study, seven independent experts in a range of disciplines (including veterinary medicine, animal behaviour and welfare science and ethics) were consulted on the relative prioritisation of welfare issues impacting companion dogs in Great Britain. Experts first anonymously ranked the priority of 37 welfare issues, pre-defined from a literature review and an earlier published survey. In a subsequent two-day panel workshop, experts refined these issues into 25 composite groups and used specific criteria to agree their relative priorities as a Welfare Problem (WP; incorporating numbers of dogs affected, severity, duration and counter-balancing benefits) and a Strategic Priority (SP; a combination of WP and tractability). Other criteria — anthropogenicity, ethical significance and confidence in the issue-relevant evidence — were also discussed by the panel. Issues that scored highly for both WP and SP were: inappropriate husbandry, lack of owner knowledge, undesirable behaviours, inherited disease, inappropriate socialisation and habituation and conformation-related disorders. Other welfare issues, such as obese and overweight dogs, were judged as being important for welfare (WP) but not strategic priorities (SP), due to the expert-perceived difficulties in their management and resolution. This information can inform decisions on where future resources can most cost-effectively be targeted, to bring about the greatest improvement in companion dog welfare in Great Britain

An experiment of the impact of a neonicotinoid pesticide on honeybees : the value of a formal analysis of the data

This work received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (Grant reference HR09011) and contributing institutions.Background: We assess the analysis of the data resulting from a field experiment conducted by Pilling et al. (2013) on the potential effects of thiamethoxam on honey bees. The experiment had low levels of replication, so Pilling et al. concluded that formal statistical analysis would be misleading. This would be true if such an analysis merely comprised tests of statistical significance and if the investigators concluded that lack of significance meant little or no effect. However, an analysis that includes estimation of the size of any effects—with confidence limits—allows one to reach conclusions that are not misleading and that produce useful insights. Main Body: For the data of Pilling et al. we use straightforward statistical analysis to show that the confidence limits are generally so wide that any effects of thiamethoxam could have been large without being statistically significant. Instead of formal analysis, Pilling et al. simply inspected the data and concluded that they provided no evidence of detrimental effects and from this that thiamethoxam poses a “low risk” to bees. Conclusions: Conclusions derived from inspection of the data were not just misleading in this case but are unacceptable in principle, for if data are inadequate for a formal analysis (or only good enough to provide estimates with wide confidence intervals) then they are bound to be inadequate as a basis for reaching any sound conclusions. Given that the data in this case are largely uninformative with respect to the treatment effect, any conclusions reached from such informal approaches can do little more than reflect the prior beliefs of those involved.Publisher PDFPeer reviewe

Density and distribution of western chimpanzees around a bauxite deposit in the Boé Sector, Guinea-Bissau

Funding: partial support by CEAUL (funded by FCT - Fundação para a Ciência e a Tecnologia, Portugal, through the project UID/MAT/00006/2019) (TAM).The Boé sector in southeast Guinea‐Bissau harbors a population of western chimpanzees (Pan troglodytes verus) that inhabits a mosaic of forest and savanna. The Boé sector contains a substantial bauxite deposit in a region called Ronde Hill, and there are plans for the construction of a mine, which may endanger the chimpanzee population. In 1‐week survey in May 2013, we used the standing crop nest counts method to obtain the number of chimpanzee nests and from that estimate the density and abundance of chimpanzees. We carried out five 1‐km line transects that covered the bauxite deposit and surrounding valleys. We used density surface modeling to analyze habitat preferences, then predicted chimpanzee nest density and distribution based on environmental variables. We found the projected location of the mine partially coincides with an area of high predicted abundances of chimpanzee nests and is surrounded by highly suitable areas for chimpanzees (northeast and southwest). We conclude the mine could have significant direct and indirect effects on this population of chimpanzees whose impacts must be carefully considered and properly mitigated if the mine is built.PostprintPeer reviewe