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Retinal temporal resolution and contrast sensitivity in the parasitic lamprey Mordacia mordax and its non-parasitic derivative Mordacia praecox
No full textLampreys and hagfishes are the sole extant representatives of the early agnathan (jawless) vertebrates. We compared retinal function of fully metamorphosed, immature Mordacia mordax (which are about to commence parasitic feeding) with those of sexually mature individuals of its non-parasitic derivative M. praecox. We focused on elucidating the retinal adaptations to dim-light environments in these nocturnally active lampreys, using electroretinography to determine the temporal resolution (flicker fusion frequency, FFF) and temporal contrast sensitivity of enucleated eyecups at different temperatures and light intensities. FFF was significantly affected by temperature and light intensity. Critical flicker fusion frequency (cFFF, the highest FFF recorded) of M. praecox and M. mordax increased from 15.1 and 21.8 Hz at 9°C to 31.1 and 36.9 Hz at 24°C, respectively. Contrast sensitivity of both species increased by an order of magnitude between 9 and 24°C, but remained comparatively constant across all light intensities. Although FFF values for Mordacia spp. are relatively low, retinal responses showed a particularly high contrast sensitivity of 625 in M. praecox and 710 in M. mordax at 24°C. This suggests selective pressures favour low temporal resolution and high contrast sensitivity in both species, thereby enhancing the capture of photons and increasing sensitivity in their light-limited environments. FFF indicated all retinal photoreceptors exhibit the same temporal response. Although the slow response kinetics (i.e. low FFF) and saturation of the response at bright light intensities characterise the photoreceptors of both species as rod-like, it is unusual for such a photoreceptor to be functional under scotopic and photopic conditions.11 page(s
Jewelled spiders manipulate colour-lure geometry to deceive prey
No full textSelection is expected to favour the evolution of efficacy in visual communication. This extends to deceptive systems, and predicts functional links between the structure of visual signals and their behavioural presentation. Work to date has primarily focused on colour, however, thereby understating the multicomponent nature of visual signals. Here I examined the relationship between signal structure, presentation behaviour, and efficacy in the context of colour-based prey luring. I used the polymorphic orb-web spider Gasteracantha fornicata, whose yellow- or white-and-black striped dorsal colours have been broadly implicated in prey attraction. In a manipulative assay, I found that spiders actively control the orientation of their conspicuous banded signals in the web, with a distinct preference for near-diagonal bearings. Further field-based study identified a predictive relationship between pattern orientation and prey interception rates, with a local maximum at the spiders' preferred orientation. There were no morph-specific effects on capture success, either singularly or via an interaction with pattern orientation. These results reveal a dynamic element in a traditionally ‘static’ signalling context, and imply differential functions for chromatic and geometric signal components across visual contexts. More broadly, they underscore how multicomponent signal designs and display behaviours may coevolve to enhance efficacy in visual deception.5 page(s
Comparison of brief versus extended personalised feedback in an online intervention for cannabis users : short-term findings of a randomised trial
No full textPrevious studies have shown brief online self-help interventions to be a useful method of treating cannabis use and related problems; however, no studies have compared the effects of brief versus extended feedback for online brief intervention programs. Objectives: The current study was a two arm randomised trial aimed at testing the short term effectiveness of a brief and extended feedback version of Grassessment, a brief online intervention for cannabis users that provides individualised feedback regarding use, motives, and harms. Methods: Participants (n = 287) reporting at least one symptom of DSM IV cannabis abuse or dependence were recruited using online and offline advertising methods. Participants were randomised to receive either a brief or extended feedback version of the Grassessment program and were required to complete a one month follow up questionnaire. Results: One hundred and ninety four participants completed the one month follow up. Wilcoxon analyses showed a significant decrease in past month quantity and frequency of cannabis use (ps < 0.001; r = − 0.41 and − 0.40 respectively) and lower severity of dependence scores (p = 0.002; r = − 0.31) among those in the brief feedback condition. Participants in the extended feedback group also demonstrated significant decreases in patterns of use (ps < 0.002; r = − 0.39 and − 0.33) but not severity of dependence (p = 0.09; r = 0.18). A Generalized Estimating Equation (GEE) analysis showed no significant interaction between length of feedback received and past month cannabis use frequency (p = 0.78), quantity (p = 0.73), or severity of dependence (p = 0.47). Conclusion: This study adds support for the use of brief online self-complete interventions to reduce cannabis use and related problems in the short term. The findings suggest that in the case of the brief online screening and feedback program Grassessment, extended feedback does not lead to superior outcomes over brief feedback.6 page(s
The Epidemiology of irritable bowel syndrome : symptom development over a 3-year period in Denmark. A prospective, population-based cohort study
No full textBackground: We aimed to explore the natural history of irritable bowel syndrome (IBS) in Denmark over 3 years by studying development of IBS symptoms and associated factors. Methods: A cohort study was carried out using a web panel representative of the Danish general population 18-50 years. The survey, including a questionnaire based on the Rome III criteria for IBS, was conducted in January 2010, January 2011, and March 2013. Key Results: The prevalence of IBS was 15.4% (920/5986). The incidence was 10.3%, and was three times higher for persons with unspecific gastrointestinal (GI) symptoms compared to asymptomatic persons. Of respondents with IBS symptoms in both 2010 and 2011, 69% (131/191) also reported symptoms of IBS in 2013, which was significantly more compared to respondents with IBS symptoms in 2010 reporting to be asymptomatic or having unspecific GI symptoms in 2011 (20% and 39%, respectively, P<.001). Being diagnosed with IBS predicted fulfilling the criteria for IBS 3 years later (OR: 2.59, 95% CI: 1.11-6.10). Fulfilling criteria for IBS after 1 year also led to a high risk of IBS symptoms 3 years later in asymptomatic persons and persons with unspecific symptoms at baseline. Conclusions & Inferences: The vast majority of persons fulfilling criteria for IBS report GI symptoms after one and 3 years. Fulfilling IBS criteria after 1 year led to a high risk of reporting IBS symptoms after 3 years. In the general population having an IBS diagnosis predicts persistently fulfilling the Rome III criteria for IBS 3 years later.9 page(s
Citation classics published in knowledge management journals. Part III : authorsurvey
No full textPurpose: This paper is the third part of a series of works investigating the top 100 knowledge management (KM) citation classic articles. The purpose of this paper is to understand why KM citation classics are well-cited. Design/methodology/approach: The results of a survey of 58 KM citation classic authors were reported as descriptive statistics and subjected to content analysis. Findings: An archetype of a KM citation classic author was constructed including demographics, personal characteristics, motivation and work preferences. There is a need for developing novel ideas in KM research. Timeliness of a publication is directly linked to its future impact. Editors should involve citation classics authors as reviewers, and KM researchers should improve their citation practices. Serendipity played a very important role in early KM research, especially from the perspective of discovering new and interesting phenomena. Research limitations/implications: Whereas the importance of serendipity is not questioned, future KM researchers should rely more on a formal, meticulous and well-planned research approach rather than on the hope of making a discovery by accident or luck. KM citation classics authors relied on serendipity to form the foundation of the discipline, but extending their work requires formal and structured inquiries. Practical implications: Many authors conducted research to solve a problem to serve the needs of both practice and academia, rather than being overly theoretical. Originality/value: Because KM researchers can no longer rely on past bibliometric theories, this paper helps understand why specific articles are highly cited and recommends how to conduct and develop future KM research that has impact.25 page(s
Representing nighttime and minimum conductance in CLM4.5 : global hydrology and carbon sensitivity analysis using observational constraints
No full textThe terrestrial biosphere regulates climate through carbon, water, and energy exchanges with the atmosphere. Land-surface models estimate plant transpiration, which is actively regulated by stomatal pores, and provide projections essential for understanding Earth's carbon and water resources. Empirical evidence from 204 species suggests that significant amounts of water are lost through leaves at night, though land-surface models typically reduce stomatal conductance to nearly zero at night. Here, we test the sensitivity of carbon and water budgets in a global land-surface model, the Community Land Model (CLM) version 4.5, to three different methods of incorporating observed nighttime stomatal conductance values. We find that our modifications increase transpiration by up to 5 % globally, reduce modeled available soil moisture by up to 50 % in semi-arid regions, and increase the importance of the land surface in modulating energy fluxes. Carbon gain declines by up to ∼ 4 % globally and > 25 % in semi-arid regions. We advocate for realistic constraints of minimum stomatal conductance in future climate simulations, and widespread field observations to improve parameterizations.11 page(s
A Simple, fast, and repeatable survey method for underwater visual 3D benthic mapping and monitoring
No full textVisual 3D reconstruction techniques provide rich ecological and habitat structural information from underwater imagery. However, an unaided swimmer or diver struggles to navigate precisely over larger extents with consistent image overlap needed for visual reconstruction. While underwater robots have demonstrated systematic coverage of areas much larger than the footprint of a single image, access to suitable robotic systems is limited and requires specialized operators. Furthermore, robots are poor at navigating hydrodynamic habitats such as shallow coral reefs. We present a simple approach that constrains the motion of a swimmer using a line unwinding from a fixed central drum. The resulting motion is the involute of a circle, a spiral-like path with constant spacing between revolutions. We test this survey method at a broad range of habitats and hydrodynamic conditions encircling Lizard Island in the Great Barrier Reef, Australia. The approach generates fast, structured, repeatable, and large-extent surveys (~110 m² in 15 min) that can be performed with two people and are superior to the commonly used “mow the lawn” method. The amount of image overlap is a design parameter, allowing for surveys that can then be reliably used in an automated processing pipeline to generate 3D reconstructions, orthographically projected mosaics, and structural complexity indices. The individual images or full mosaics can also be labeled for benthic diversity and cover estimates. The survey method we present can serve as a standard approach to repeatedly collecting underwater imagery for high-resolution 2D mosaics and 3D reconstructions covering spatial extents much larger than a single image footprint without requiring sophisticated robotic systems or lengthy deployment of visual guides. As such, it opens up cost-effective novel observations to inform studies relating habitat structure to ecological processes and biodiversity at scales and spatial resolutions not readily available previously.13 page(s
An examination of independent directors in Vietnam
No full textThesis by publication.Bibliography: pages 179-195.Chapter 1. Introduction -- Chapter 2. Independent directors, ownership concentration and firm performance in listed companies : evidence from Vietnam -- Chapter 3. Roles of and challenges for independent directors in transition economies : evidence from Vietnam -- Chapter 4. Impact of cultural difference between the north and the south of Vietnam on creating accountability of independent directors -- Chapter 5. Conclusion -- References -- Appendices.Vietnam is a transition economy in the Southeast Asia and corporate governance in this country has been newly established after transition process in 1986. Similar to many other developing and emerging economies, Vietnam has weak external governance mechanisms, thus independent director becomes a critical element in corporate governance system as an internal governance mechanism. Further, Vietnam is also a transition economy which has a highly concentrated ownership structure with the dominance of the State as the largest controlling shareholder which may complicate the work of independent directors. Therefore, it is unclear how independent directors contributes to corporate governance and firm performance in a transition economy as Vietnam. Vietnam only releases a new Corporate Governance Code in 2012 which for the first time introduces the notion of independent directors in corporate governance with the requirement that listed companies need to maintain a certain level of independent directors on the board. There is lack of research to examine the function of independent directors in corporate governance in this country. Taking into account the importance as well as the recent adoption of independent director in corporate governance in Vietnam – a transition economy, the thesis examines this type of director from three aspects in three research papers.The first paper (chapter 2) examines the relationship between independent directors and firm performance using available archival data. Due to the nature of transition process, independent directors have been recently adopted in corporate governance system in Vietnam, thus contribution of independent directors to improving firm performance is still unclear. After using several methods to control for endogeneity - a common issue for research on corporate governance, we found that the relationship between independent directors and firm performance is negative. The findings also revealed that the negative relationship between independent directors and firm performance can be due to the dominance of firms with concentrated ownership structure. In addition, the negative relationship is even worse in firms where the State is a controlling shareholder than in firms with private controlling shareholders.Then, in the second paper (chapter 3), the thesis uses surveys to further investigate the perceptions of independent directors in listed companies in Vietnam on the roles, responsibilities and challenges for them when participating on the board of directors. The main purpose of this paper is to understand how independent directors recognize their roles in corporate governance in the absence of guidelines from corporate governance codes released in 2012 in Vietnam. The findings suggested that independent directors have preference on advisory role than monitoring role which is not suggested by prior literature. In addition, they also pointed out the challenges faced in the board including information asymmetries and influence of controlling shareholders.Finally, the third paper (chapter 4) investigated if there is any cultural difference between the north and the south of Vietnam and if this intra-cultural difference is associated with difference in creating accountability of independent directors. The results confirmed the persistence of intra-cultural difference in Vietnam between two regions in which independent directors in the south are more likely to be individualists whereas independent directors in the north are more likely to be collectivists. Additionally, independent directors in the south demonstrated a lower level of risk averse while independent directors in the north showed a higher level of risk averse. With regard to creating accountability of independent directors, the results demonstrated that independent directors in the south are more likely to be at higher level of creating accountability than directors in the north.Overall, the thesis points out some issues relating to independent directors in Vietnam and provide implications to policymakers for a further corporate governance reform relating to independent directors as well as to companies when establishing and maintaining their corporate governance systems.Mode of access: World wide web1 online resource (217 pages) table
Business excellence models as sources of benchmarking and improvement
No full textThesis by publication.Bibliography: pages 178-191.Chapter 1. Research overview -- Chapter 2. A comprehensive view on research excellence -- Chapter 3. Business process rearrangement and renaming - a new approach to process orientation and improvement -- Chapter 4. Aiming for excellence : commitment matters -- Chapter 5. Discussion - Chapter 6. Conclusion -- Appendices.There has always been a significant debate about management models and systems in the literature. This thesis focuses on Business Excellence (BE) models, and their impact on the process maturity and performance. Through a case-study and a survey in UK firms, this study shows that utilising and commitment to BE models is significantly related to process maturity and financial performance. Not only BE-active firms were in a better situation than non-BE-active firms, but also within the BE-active companies, those who showed a higher level of commitment, were higher in their process maturity and financial performance.This is a thesis by publication presenting several contributions to the existing knowledge. The literature review has resulted in a conceptual paper including the first comprehensive scientific excellence model. Following the literature review, a case-study is presented in the second paper proposing a new process orientation methodology, namely the ‘Business Process Rearrangement and Renaming (BPR2)’ boosted by BE. The power of names which has been so far neglected in management literature, has been utilised in BPR2. Instead of destroying the organisational structure and rebuilding it, BPR2 suggests giving each of the existing departments ‘a new identity and responsibility’ to provide specific products/services for the internal/external customers.A survey has been conducted on the impacts of commitment to BE which resulted in proposition of the new ‘Organized Commitment Model’ presented in the third paper. This model provides a platform for top managers who want to establish commitment on highly important issues such as organisational values, strategies, customer relationship, and so on. The Model can be also used by academics who want to measure the impact of commitment to an issue such as commitment to strategies on another variable such as performance.‘Aiming for Excellence’ is the central focus in the whole thesis. Although people present different definitions about excellence, overall understanding of people about this concept is very similar. Hence, ‘Aiming for Excellence’ can provide a shared vision that brings people together in difficult circumstances.Mode of access: World wide web1 online resource (viii, 191 pages) diagrams, table
Simulation study of propane refrigerant for heat pump water heaters
No full textEmpirical thesis.Bibliography: pages 69-71.1. Introduction -- 2. Background and related work -- 3. Energy analysis and software theoretical model -- 4. Methodology -- 5. Results and discussions -- 6. Conclusion -- 7. Future work -- 8. Abbreviations -- 9. Appendix -- 10. References.Heat pumps are becoming an essential part of our daily lives due to their high efficiency when compared to the traditional water heating systems. The choice of refrigerant is one of the main issues for the HPWHs. Hydrofluorocarbons (HFCs) chlorofluorocarbons (CFCs) are still being used, but global warming and ozone depletion remain problems due to their high GWP and ODP. Propane R290 is found to be a better and cheap alternative which could be uyilised for HPWH systems due to its better GWP and ODP.This study involves the numerical simulation via IMST-ART simulation software. The software was used to simulate propane R290 which was compared with refrigerants R134a and R407C. To analyse the COP of R290, compressors with different stroke displacement and input power were also modelled on the software.The results indicate that refrigerant R290 was able to achieve better COP as the ambient temperature goes higher, whereas the COP for refrigerants R134a and R407C decreases at higher ambient temperature. The results for different input power compressor indicated that the compressor with the lower input power was able to achieve higher COP, when compared with the higher input power compressor.Mode of access: World wide web.1 online resource (xvi, 71 pages colour illustrations