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Virtual pheromone based network flow control for modular robotic systems
No full textGuaranteeing data transmission between modules is the key for application development of modular robotic systems. In a multi-channel modular robotic system, intersection modules play an essential role of communication channel selection in controlling data flow toward desired destinations. The gradient-based routing algorithm is an ideal solution to create an one-way communication path from any robotic module to a designated destination. To create bi-directional communication for a communication path of robotic configuration, virtual pheromone-based routing algorithm is a promising mechanism for intersection modules due to its simplicity and distributivity. In this paper, we address a virtual pheromone based network flow control based on the integration of gradient and virtual pheromone-based routing algorithms. We validated this method through an education and entertainment application using our newly developed modular robotic system.Natural Sciences and Engineering Research Council of Canada
Visual cues promote head first strategies during walking turns in individuals with Parkinson's disease
No full textAnticipatory eye movement promotes cranio-caudal sequencing during walking turns. Clinical groups, such as Parkinson's disease (PD), do not produce anticipatory eye movements, leading to increased risk of falls. Visual cues may promote anticipatory eye movement by guiding the eyes into the turn. This study examined if visual cues could train anticipatory eye movement. Ten neurotypical young adults and 6 adults with PD completed three blocks of walking trials. Trials were blocked by visual condition: non-cued baseline turns (5 trials), visually cued turns (10 trials), and non-cued post turns (5 trials). A Delsys Trigno (Delsys, Boston, MA) recorded horizontal saccades at 1024 Hz via electrooculography (EOG). Two Optotrak cameras (Northern Digital Inc., ON, Canada) captured body segment kinematics at 120 Hz. Initiation of segment rotation with respect to ipsilateral foot contact (IFC1) prior to the turn was calculated. Neurotypical young adults (NYA) produced typical cranio-caudal rotation sequences during walking turns. Eyes led (407 ms prior to IFC1), followed by the head (50 ms prior to IFC1), then trunk and pelvis. In contrast, PD produced no anticipatory eye or segment movement at baseline. During pre-trials the eyes moved 96 ms after IFC1 and segment movement was initiated by the pelvis followed by trunk and head segments. After visual cue training however, PD produced anticipatory eye movements 161 ms prior to IFC1, followed by the head 88 ms following IFC1 but ahead of trunk and pelvis onset. These results suggest visual cues assist in producing cranio-caudal control during walking turns in PD
Benchmarking human performance in semi-automated image segmentation
No full textSemi-automated segmentation algorithms hold promise for improving extraction and identification of objects in images such as tumors in medical images of human tissue, counting plants or flowers for crop yield prediction or other tasks where object numbers and appearance vary from image to image. By blending markup from human annotators to algorithmic classifiers, the accuracy and reproducability of image segmentation can be raised to very high levels. At least, that is the promise of this approach, but the reality is less than clear. In this paper, we review the state-of-the-art in semi-automated image segmentation performance assessment and demonstrate it to be lacking the level of experimental rigour needed to ensure that claims about algorithm accuracy and reproducability can be considered valid. We follow this review with two experiments that vary the type of markup that annotators make on images, either points or strokes, in tightly controlled experimental conditions in order to investigate the effect that this one particular source of variation has on the accuracy of these types of systems. In both experiments, we found that accuracy substantially increases when participants use a stroke-based interaction. In light of these results, the validity of claims about algorithm performance are brought into sharp focus, and we reflect on the need for a far more control on variables for benchmarking the impact of annotators and their context on these types of systems.Mathematics of Information Technology and Complex Systems (MITACS) Globallink Progra
Adult-born hippocampal neurons undergo extended development and are morphologically distinct from neonatally-born neurons
No full textDuring immature stages, adult-born neurons pass through critical periods for survival and plasticity. It is generally assumed that by 2 months of age adult-born neurons are mature and equivalent to the broader neuronal population, raising questions of how they might contribute to hippocampal function in old age when neurogenesis has declined. However, few have examined adult-born neurons beyond the critical period or directly compared them to neurons born in infancy. Here, we used a retrovirus to visualize functionally relevant morphological features of 2- to 24-week-old adult-born neurons in male rats. From 2 to 7 weeks, neurons grew and attained a relatively mature phenotype. However, several features of 7-week-old neurons suggested a later wave of growth: these neurons had larger nuclei, thicker dendrites, and more dendritic filopodia than all other groups. Indeed, between 7 and 24 weeks, adult-born neurons gained additional dendritic branches, formed a second primary dendrite, acquired more mushroom spines, and had enlarged mossy fiber presynaptic terminals. Compared with neonatal-born neurons, old adult-born neurons had greater spine density, larger presynaptic terminals, and more putative efferent filopodial contacts onto inhibitory neurons. By integrating rates of cell birth and growth across the life span, we estimate that adult neurogenesis ultimately produces half of the cells and the majority of spines in the dentate gyrus. Critically, protracted development contributes to the plasticity of the hippocampus through to the end of life, even after cell production declines. Persistent differences from neonatal-born neurons may additionally endow adult-born neurons with unique functions even after they have matured
Community-based learning for international graduate students: Impact and implications
No full textIntegrating community-based learning (CBL) into graduate education has gained attention in higher education during the past decade because CBL allows students to inculcate professional values and ethics, situate academic knowledge and understanding in contexts, and practice academic citizenship through serving communities with disciplinary knowledge and skills. In a North American higher education context, about half of the graduate student population are international students, who have needs in several areas. However, their experiences in CBL are under-investigated and scarcely documented in existing literature and scholarship in either community-based learning or international education. Drawing on international students’ experiences in a graduate program infused with CBL components in Canadian higher education, this mixed methods case study examined the impact of CBL on international students’ developments in five areas: academic, sociocultural, personal, professional, and global citizenship. Through discussions on the benefit, barriers, and implications of providing CBL to international graduate students, this article offers recommendations for improved higher education policy, programs, and praxis to make CBL more inclusive and responsive to international graduate students
Just the facts: Hypertension in the emergency department
No full textA 65-year-old female smoker complains of dizziness and mild headache. While at the local pharmacy buying acetaminophen, she decides to check her blood pressure to see if it could be "causing her symptoms." Her initial measurement is 220/96 mm Hg. In consultation with the on-duty pharmacist she is instructed to immediately attend the emergency department (ED) for management of her hypertension
Short communication: Describing mortality and euthanasia practices on Canadian dairy farms
No full textThe objective of this study was to describe mortality rates and euthanasia practices used for cows, heifer calves, and male dairy calves on Canadian dairy farms. An internet survey was administered to Canadian dairy producers between March and April 2015 to collect information on current management practices. Approximately 81% (867/1,076) and 63% (673/1,065) of respondents reported that at least one animal died unassisted and at least one animal was euthanized on the farm in the preceding 12-mo period, respectively. Overall, mean mortality was 8% for cows, and 6 and 2% for preweaning and weaned heifers, respectively. On average, 48, 76, and 89% of all reported mortality events in cows, weaned heifers, and preweaning heifers were recorded as unassisted deaths. Cows that died without assistance were necropsied more often than preweaning heifers dying without assistance; these cows were also necropsied more than cows that were euthanized. Conversely, preweaning heifers that were euthanized were necropsied more frequently than those that died without assistance. Choosing not to perform necropsies on animals that die of unknown causes could represent a missed opportunity to identify cause of death and inform changes to prevent future deaths. The use of a firearm was the most common method for euthanizing cows and heifers (54%) and male dairy calves (51%). Approximately 7% of respondents reported using blunt force to euthanize animals. The use of this method was much higher for euthanasia of male dairy calves (34%) than for heifer calves (7%). Quebec respondents euthanized their animals using blunt force more often than farmers from other regions. Further, 53% of respondents using blunt force indicated it was their primary method of calf euthanasia; these results are extremely concerning. Approximately 31% of respondents who reported that they do not use blunt force to euthanize heifers and cows did report using blunt force to euthanize male dairy calves. These results can be used to inform veterinarian--client communication, broader extension tools and programs, and industry policies to improve dairy cattle health and welfare, a goal that is becoming of increasing importance from a consumer assurance perspective.Dairy Farmers of CanadaAgriculture and Agri-Food Canad
Canadian National Dairy Study: Describing Canadian dairy producer practices and perceptions surrounding cull cow management
No full textFarmer decisions surrounding culling have an important effect on the health and welfare of cull cows. The objectives of this study were to describe the self-reported shipment behaviors of Canadian dairy producers and understand farmer perspectives on the factors that were most influential in their decision to cull a cow. A nationwide survey was administered between March and April 2015 that included 192 questions covering producer background information, farm characteristics, biosecurity practices, disease prevalence, calf health, cow welfare, lameness, milking hygiene, reproduction, and Internet and social media use. The survey yielded a 12% response rate; a total of 1,076 respondents (78% of all survey respondents completed the culling section of the survey) were included in this study for analysis. Approximately 80, 51, and 38% of respondents reported shipping at least 1 cow to auction, direct to slaughter, and to another dairy farm in the past 12 mo, respectively. Ability of the cow to remain standing (93% of respondents) and drug withdrawal times (92% of respondents) were identified as the most important factors for consideration when culling cows. The time between culling decision and when the cow was actually transported was longer for lame cows than sick cows; almost 70% of respondents reported that cows culled for illness were typically shipped within 1 wk of culling decision, whereas only 51% of respondents indicated the same was true for lame cows. Last, Canadian dairy producers generally exhibited strong confidence that their culled cows would arrive at slaughter in the same condition as they left, but felt very unsure about knowing the location of their final destination. These results highlight several gaps between producer perceptions and the true situation, and can be used to develop tailored programs and inform policy and regulatory decisions aimed at improving cull cow decisions and cow welfare.Dairy Farmers of CanadaAgriculture and Agri-Food Canad
Fishway Effectiveness and Upstream Residency of Three Fish Species at Four Fishways in Prince Edward Island, Canada
No full textWe evaluated passage of Osmerus mordax (Rainbow Smelt), Salvelinus fontinalis (Brook Trout), and Alosa pseudoharengus (Alewife) at 4 fishways on Prince Edward Island, Canada. We implanted fish with passive integrated transponder (PIT) tags and recorded their movements using stationary PIT antennas. Passage at different fishway types was highly variable. Nature-like fishways passed over 96% of Brook Trout and a maximum of 41.8% of Rainbow Smelt. The latter percentage is the highest yet reported in the literature for Rainbow Smelt. Pool-and-weir fishways passed nearly 100% of Brook Trout, 13.2% of Rainbow Smelt, and only 5.6% of Alewife. After passing a fishway, upstream residency was highly variable both among species as well as among individuals within species. Rainbow Smelt were observed spawning within nature-like fishways, suggesting that this type of fishway may also provide spawning habitat. Results highlight the challenge of passing non-salmonid species and indicate nature-like fishways are more appropriate than technical designs for passing Rainbow Smelt
Fukui foldable traps versus fyke nets as options for fishing European green crabs (Carcinus maenas) in soft-bottom habitats: Exploring efficiency and limiting bycatch
No full textThe European green crab (Carcinus maenas) continues to expand in Atlantic Canada and other coastal regions worldwide. Since most control measures for this species have failed, there is a need for innovative and ecologically responsible mitigation measures. One such measure is a green crab control harvesting wherein affected fishers could recoup some of their losses through value-added products. As with any new control initiative, gear choice must be carefully considered. This study assessed catch efficiency and bycatch of two common gear: Fukui foldable traps and fyke nets. Both types of gear were systematically compared in two soft-bottom areas with abundant green crab populations over the course of a field season (early May–late September). In this study, fyke nets were more efficient, catching roughly three times the number of green crabs caught by individual Fukui foldable traps. However, fyke nets also caught nearly ten times more bycatch and doubled the number of native species caught. Fyke net bycatch also included proportionally higher numbers of endangered and commercially important species, such as American eel (Anguilla rostrata) and winter flounder (Pleuronectes americanus). Although in principle Fukui foldable traps seem better suited for green crab control because of lesser bycatch impacts, further studies should find ways to increase Fukui foldable trap efficiency or test fyke nets with bycatch reduction devices