Design of a processor to support the teaching of computer systems

Teaching computer systems, including computer architecture, assembly language programming and operating system implementation, is a challenging occupation. At the University of Waikato this is made doubly true because we require all computer science and information systems students study this material at second year. The challenges of teaching difficult material to a wide range of students have driven us to find ways of making the material more accessible. The corner stone of our strategy for delivering this material is the design and implementation of a custom CPU that meets the needs of teaching. This paper describes our motivation and these needs. We present the CPU and board design and describe the implementation of the CPU in an FPGA. The paper also includes some reflections on the use of a real CPU rather than a simulation environment. We conclude with a discussion of how the CPU can be used for advanced classes in computer architecture and a description of the current status of the project

Habitat use by the southern red-backed vole (Clethrionomys gapperi) : response of an old-growth associated species to succession

I examined populations of the southern red-backed vole ( Clethrionomys gappen) and deer mouse (Peromyscus maniculatus) in 4 successional stages (65, 138, 256, 457 Y) in cedar-hemlock (Thuja plicata-Tsuga heterophylla) forests of Glacier National Park to determine macrohabitat selection among stands and microhabitat selection within stands. Abundance of Clethrionomys gapperi and Peromyscus maniculatus increased with increasing stand age. Microhabitat use differed from available habitat for both species within most age classes, but was not consistent for either species among age classes. The inconsistency in microhabitat use among successional stages and lack of correspondence between micro- and macrohabitat variables selected leads to the conclusion that macrohabitat associations determine microhabitat selection. In order to properly assess habitat use at either scale the difference between scales must be addressed in the design and analysis of habitat studies. Peromyscus maniculatus behaved as a generalist at the macrohabitat scale, but exhibited stronger microhabitat selection than did C. gapperi. I suggest that P. maniculatus may exhibit habitat switching and respond to local site conditions by developing search images that manifest themselves as distinctive foraging patterns at the microhabitat scale. Such behavior would render P. maniculatus a potentially formidable competitor for resources and explain its tenacity for a wide variety of habitats. Clethrionomys gapperi exhibits a strong positive linear relationship with stand age and old-growth conditions near the forest floor. If monitored in conjunction with other species such as the pine marten (Martes americana), pileated woodpecker (Dryocopus pileatus) and barred owl (Strix asio), C. gapperi could contribute significantly to an indicator guild for identifying and monitoring the old-growth condition. I also compared fluorescent pigment tracking and live trapping to determine microhabitat use by Clethrionomys gapperi. The two methods generally agreed, but fluorescent pigment tracking may allow more sensitive analyses of microhabitat use

The impact of the ISO 9001:2015 on organisational change in South African organisations

In order for organisations to grow and maintain their competitive advantage, change has become the norm. Quality management systems are increasingly being deployed as a means to maintain this advantage, and enhance the quality of product and service offerings. The implementation of the latest publication of ISO9001:2015 requires organisations to have a more holistic overview and understanding of leadership requirements, planning as well as the organisational context they operate in. A positivistic research paradigm, with a quantitative, explorative and deductive approach was used to conduct the study. The study explored the requirements of change in organisations implementing the latest publication of ISO9001:2015 within the Nelson Mandela Metropolitan area. It aimed at exploring the relationship between selected demographic variables, and the variables of the study. Lastly, the relationship between organisational context, planning and leadership (independent variables) and organisational change (dependent variable) were explored. The sample comprised of 81 organisations that were based in the Eastern Cape having their quality management systems based on the ISO9001 structure. A structured questionnaire with a Cronbach‘s alpha of more than 0.8 was used to collect data and distributed to lower, middle and upper level managers within these selected organisations. The empirical results indicated that the variables under study were prevalent in the organisations currently ISO9001 certified and in the process of implementing the latest version of the standard. However, the sizes of the studied organisations were found to present the most noteworthy differences, highlighting the current and future requirements for successful organisational change. Recommendations related to the findings were made for managers, as well as for research, and industry. Ethical principles were maintained throughout the study

Drift of Oligophlebodes sigma and Baetis bicaudatus in a Mountain Stream

The objective of this study was to clarify the relationships between drift rates, population density, production rates, key environmental factors, and movements of adults within two populations of stream insects (a caddisfly--Oligophlebodes sigma and a mayfly--Baetis bicaudatus). Samples of benthic invertebrates (424 total) were collected every 2 8 days at four stations on Temple Fork of the Logan River, Utah, from October, 1967 to September, 1969. Samples of drift invertebrates (181 total) were collected every 14 days at three stations on Temple Fork during the same period. During summer months (June-September) a day and a night drift sample (681 total) were collected every other day. Drift rates of O. sigma larvae were greatest (5,987 gm/year for O. sigma) when density in the benthos (256 mg/0.1 m2) and production (430 mg/0.1 m2 /year) were greatest. Drift rates were not related positively to density in the benthos over an entire year, but drift rates were correlated positively and significantly (r = .78 and .55 for day drift of O. sigma and B. biaaudatus, respectively) with density during the months of June-September for both O. sigma larvae and B. bicaudatus nymphs. Flow, distance below the spring source of Temple Fork, and densities of competing aquatic insects were other factors of significance in the multiple regression analyses of factors affecting drift rates of the two insects. The 17 independent variables in the multiple regression analyses accounted for 65 percent and 55 percent of the variability in day drift rates of o. sigma and B. bicaudatus, respectively. The adults of O. sigma (but not those of B. bicaudatus) undertook a definite upstream migration estimated at 2-3 km. This flight of adults resulted in a concentration of eggs being laid in the upper reaches of the stream. The advantage of the upstream flight may be that it stores reproductive products in areas where they are relatively safe from the effects of anchor-ice in the winter and floods in late winter and early spring

Are Local Filters Blind to Provenance? Ant Seed Predation Suppresses Exotic Plants More than Natives

The question of whether species’ origins influence invasion outcomes has been a point of substantial debate in invasion ecology. Theoretically, colonization outcomes can be predicted based on how species’ traits interact with community filters, a process presumably blind to species’ origins. Yet, exotic plant introductions commonly result in monospecific plant densities not commonly seen in native assemblages, suggesting that exotic species may respond to community filters differently than natives. Here, we tested whether exotic and native species differed in their responses to a local community filter by examining how ant seed predation affected recruitment of eighteen native and exotic plant species in central Argentina. Ant seed predation proved to be an important local filter that strongly suppressed plant recruitment, but ants suppressed exotic recruitment far more than natives (89% of exotic species vs. 22% of natives). Seed size predicted ant impacts on recruitment independent of origins, with ant preference for smaller seeds resulting in smaller seeded plant species being heavily suppressed. The disproportionate effects of provenance arose because exotics had generally smaller seeds than natives. Exotics also exhibited greater emergence and earlier peak emergence than natives in the absence of ants. However, when ants had access to seeds, these potential advantages of exotics were negated due to the filtering bias against exotics. The differences in traits we observed between exotics and natives suggest that higher-order introduction filters or regional processes preselected for certain exotic traits that then interacted with the local seed predation filter. Our results suggest that the interactions between local filters and species traits can predict invasion outcomes, but understanding the role of provenance will require quantifying filtering processes at multiple hierarchical scales and evaluating interactions between filters.Fil: Pearson, Dean. University of Montana; Estados Unidos. United States Department of Agriculture; Estados UnidosFil: Icasatti, Nadia Soledad. United States Department of Agriculture; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hierro, Jose Luis. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Bird, Benjamin B.. United States Department of Agriculture; Estados Unido

Adaptive cancelation of self-generated sensory signals in a whisking robot

Sensory signals are often caused by one's own active movements. This raises a problem of discriminating between self-generated sensory signals and signals generated by the external world. Such discrimination is of general importance for robotic systems, where operational robustness is dependent on the correct interpretation of sensory signals. Here, we investigate this problem in the context of a whiskered robot. The whisker sensory signal comprises two components: one due to contact with an object (externally generated) and another due to active movement of the whisker (self-generated). We propose a solution to this discrimination problem based on adaptive noise cancelation, where the robot learns to predict the sensory consequences of its own movements using an adaptive filter. The filter inputs (copy of motor commands) are transformed by Laguerre functions instead of the often-used tapped-delay line, which reduces model order and, therefore, computational complexity. Results from a contact-detection task demonstrate that false positives are significantly reduced using the proposed scheme

‘Making Sense’ of Urinary Incontinence: A Qualitative Study Investigating Women’s Pelvic Floor Muscle Training Adherence

Urinary incontinence is common and disabling. Pelvic floor muscle training is recommended as first-line therapy for uncomplicatedurinary incontinence. The effects of such behavioural therapies depend in part on adherence. We explored women’s experiences ofincontinence treatment and training adherence in a longitudinal qualitative design. Six women (40–80 years) with stress, urgencyor mixed urinary incontinence symptoms were interviewed twice; once at the start of treatment and again after discharge about 3months later. Interviews were transcribed and analysed using principles of Interpretative Phenomenological Analysis. Experienceswere represented by four themes: Past experiences and meanings of leakage; the supervised treatment period; going on and lookingahead; and the relationship with and experience of others. Variable adherence was explained by how women ‘made sense of it all’.Women with the least difficulty in making sense of their incontinence and in overcoming training inertia had the best self-reportedoutcomes. Conversely, variable adherence, poorer self-reported outcomes, and ambivalence about engaging in treatment werecharacteristic of women who struggled to make sense of their apparently intermittent or unpredictable condition. Helping womenmake sense of incontinence and overcome inertia and ambivalence could improve adherence, but this may be a prolonged process

Weed-Biocontrol Insects Reduce Native-Plant Recruitment Through Second-Order Apparent Competition

Small-mammal seed predation is an important force structuring native-plant communities that may also influence exotic-plant invasions. In the intermountain West, deer mice (Peromyscus maniculatus) are prominent predators of native-plant seeds, but they avoid consuming seeds of certain widespread invasives like spotted knapweed (Centaurea maculosa). These mice also consume the biological-control insects Urophora spp. introduced to control C. maculosa, and this food resource substantially increases deer mouse populations. Thus, mice may play an important role in the invasion and management of C. maculosa through food-web interactions. We examined deer mouse seed predation and its effects on seedling emergence and establishment of a dominant native grass, Pseudoroegneria spicata, and forb, Balsamorhiza sagittata, in C. maculosa-invaded grasslands that were treated with herbicide to suppress C. maculosa or left untreated as controls. Deer mice readily took seeds of both native plants but removed 2–20 times more of the larger B. sagittata seeds than the smaller P. spicata seeds. Seed predation reduced emergence and establishment of both species but had greater impacts on B. sagittata. The intensity of seed predation corresponded with annual and seasonal changes in deer mouse abundance, suggesting that abundance largely determined mouse impacts on native-plant seeds. Accordingly, herbicide treatments that reduced mouse abundance by suppressing C. maculosa and its associated biocontrol food subsidies to mice also reduced seed predation and decreased the impact of deer mice on B. sagittata establishment. These results provide evidence that Urophora biocontrol agents may exacerbate the negative effects of C. maculosa on native plants through a form of second-order apparent competition—a biocontrol indirect effect that has not been previously documented. Herbicide suppressed C. maculosa and Urophora, reducing mouse populations and moderating seed predation on native plants, but the herbicide\u27s direct negative effects on native forb seedlings overwhelmed the indirect positive effect of reducing deer mouse seed predation. By manipulating this four-level food chain, we illustrate that host-specific biological control agents may impact nontarget plant species through food-web interactions, and herbicides may influence management outcomes through indirect trophic interactions in addition to their direct effects on plants. Read More: http://www.esajournals.org/doi/abs/10.1890/07-1789.1?journalCode=eca

Small-Mammal Seed Predation Limits the Recruitment and Abundance of Two Perennial Grassland Forbs

Although post-dispersal seed predators are common and often reduce seed density, their influence on plant population abundance remains unclear. On the one hand, increasing evidence suggests that many plant populations are seed limited, implying that seed predators could reduce plant abundance. On the other hand, it is generally uncertain whether the magnitude of seed limitation imposed by granivores is strong enough to overcome density-dependent processes that could compensate for seed loss at later stages. We examined the impact of seed predation by small mammals, primarily deer mice (Peromyscus maniculatus), on seedling recruitment and subsequent plant establishment of two perennial grassland forbs in western Montana, USA: Lupinus sericeus (Fabaceae) and Lithospermum ruderale (Boraginaceae). The experiment combined graded densities of seed addition for each species with a small-mammal exclusion treatment. Seedling recruitment and plant establishment were monitored in the experimental plots for up to three years. For both species, small-mammal exclusion increased the total number of seedlings that emerged, and these effects were still significant three years after seed addition, resulting in greater numbers of established plants inside exclosures than in control plots. We also found evidence of seed limitation, with increasing density of seeds added leading to increased numbers of seedlings. Results from seed addition and small-mammal exclusion experiments in later years also revealed significant impacts of small mammals on seedling emergence. These results suggest that granivores can have potentially important impacts in limiting forb abundance in grasslands communities