Breeding, Moulting, and Site Fidelity of Brant (Branta bernicla) on Bathurst and Seymour Islands in the Canadian High Arctic

We studied the breeding and moulting ecology of eastern High Arctic brant Branta bernicla hrota on Bathurst and Seymour Islands in the central Canadian High Arctic from 1968 to 1989. In most years, brant arrived in Polar Bear Pass, Bathurst Islnd, during the first few days of June (earliest 28 May 1977), where they fed for several days in small flocks before dispersing to nesting areas. First eggs were usually laid on 13 June and the peak of nest initiation occurred about 16 June. The mean clutch size was 4.5 eggs, and the mean incubation period 23 days. Broods were raised along the shorelines of lakes, ponds, estuaries, and rivers. Goslings were capable of flight by 42-43 days. During the 10 years when the studies were most intensive (1974-77 and 1984-89), there were three years in which brant did not attempt to nest (1974, 1986, 1988); they nested in all other years and were known to produce fledged young in at least four of them. Nesting was not attempted when the mean temperature for the period 1-20 June was below -3 C. On Bathurst Island in 1987, arctic foxes (Alopex lagopus) preyed heavily on brant eggs, and no young were fledged. Nonbreeding adults assembled in small flocks to moult around nerby inland lakes, in river valleys, and at the mouths of estuaries, and concentrated in the latter in cold summers when inland sites had heavier ice cover. The flightless period began about 6 July and lasted 20-22 days. The recapture or resighting of brant marked on Bathurst Island showed that many adults returned in subsequent years to the same breeding territories, and in nonbreeding years they moulted nearby. A smaller proportion of the brant that had been marked as goslings and yearlings also returned to the island. In comparison with most other stocks of North American brant, those we studied bred at high latitude. That choice of breeding site subjected them to periodic breeding failures caused by cold springs and to a reduced availability of plant biomass, but it offered the advantage of reduced spring snow depth and a full 24 h of daylight for feeding during nesting and brood rearing. By using small wetlands which thaw early in close proximity to nesting sites, these brant were able to initiate egg laying relatively early and produce large clutches in most years. The low availability of plant biomass in the High Arctic probably explained the wide dispersal and low densities of these brant during breeding and moulting.De 1968 à 1989, nous avons étudié l'écologie de reproduction et de mue de la bernache cravant à ventre pâle Branta bernicla hrota dans les îles Bathurst et Seymour situées dans la partie centrale de l'Extrême-Arctique canadien. En général, les bernaches cravants arrivaient dans la vallée Polar Bear de l'île Bathurst durant les premiers jours de juin (le plus tôt étant le 28 mai 1977); elles s'alimentaient par petits groupes pendant plusieurs jours avant de se disperser vers les sites de nidification. Les premiers oeufs étaient généralement pondus le 13 juin et le pic du début de la ponte se situait vers le 16 juin. La taille moyenne de la couvée était de 4,5 oeufs/nid et la durée moyenne d'incubation était de 23 jours. Les couvées étaient élevées en bordure des lacs, des étangs, des estuaires et des cours d'eau. Les oisons étaient capables de voler à 42 ou 43 jours. Au cours des 10 années d'étude intensive (1974-77 et 1984-89), il y en a eu trois pendant lesquelles les bernaches cravants n'ont pas essayé de nicher (1974, 1986, 1988); par contre, elles ont niché toutes les autres années et ont réussi à élever des oisons jusqu'à l'âge d'envol au moins quatre de ces années. Les bernaches cravants n'ont pas essayé de nicher les années où la température moyenne pour la période allant du 1er au 20 juin était inférieure à -3 °C. En 1987, des renards arctiques Alopex lagopus ont prélevé quantité d'oeufs de bernaches cravants dans l'île Bathurst et aucun oison n'a survécu jusqu'à l'âge d'envol. Des adultes non reproducteurs se rassemblaient localement en petits groupes pour muer près des lacs, des rivières et de l'embouchure des estuaires, préférant, durant les étés froids, des estuaires normalement plus dégagés de glace que des sites à l'intérieur des terres. La période de mue débutait autour du 6 juillet et durait de 20 à 22 jours environ. Des bernaches cravants qui avaient été marquées dans l'île Bathurst y ont été observées de nouveau ou y ont été recapturées durant les années subséquentes, prouvant ainsi qu'un grand nombre d'adultes reviennent sur les mêmes aires de reproduction et, pendant les années de non-reproduction, elles muaient à proximité. Une proportion moindre de bernaches cravants marquées au stade juvénile (soit < 2 mois, soit à l'âge d'un an) sont aussi revenues à l'île Bathrust. Comparées à d'autres populations nord-américaines de bernaches, celles que nous avons étudiées se reproduisent à une latitude élevée. En nichant dans l'Extrême-Arctique, cette population était sujette à des échecs périodiques dus à des printemps froids ainsi qu'à une disponibilité réduite de biomasse végétale. Elle bénéficiait par contre d'une faible accumulation de neige au printemps et de 24 heures quotidiennes de clarté pour se nourrir pendant la nidification et l'élevage des oisons. En exploitant de petites superficies de terres humides qui dégèlent tôt, à proximité des sites de nidification, ce bernaches cravants pouvaient, la plupart des années, pondre relativement tôt en saison et produire des couvées de bonne taille. La disponibilité réduite de biomasse végétale dans l'Extrême-Arctique expliquait probablement la dispersion étendue et les faibles densités de ces bernaches cravants en période de reproduction et de mue

Student Work Placement: Friend or Foe? A study of the perceptions of university students on industrial work placement

At the National University of Ireland Maynooth, Computer Science and Software Engineering students are required to undertake an industrial work placement module as part of their course. The work placement is typically six to eighteen months long and takes place in the penultimate year of the degree. This paper evaluates students’ perception of the quality of the learning experience they received through work placement. The voice of many key players involved in the process is captured, including, the students themselves, members of the academic department and the Industrial Work Placement Office; and importantly this paper is authored by representatives of each of these groups. In particular, the paper evaluates the types of preparations students make prior to commencing a placement, the transferable skills acquired and improved during their placement, and student perceptions of the advantages and disadvantages of their placement. A mixed data acquisition model is used for gathering data including questionnaires, interviews and focus groups. The gathered data is analysed and a critique on the findings is presented. The paper concludes with recommendations and considerations for any institution that is interested in offering an industrial work placement component

Can a Computationally Creative System Create Itself? Creative Artefacts and Creative Processes

This paper begins by briefly looking at two of the dominant perspectives on computational creativity; focusing on the creative artefacts and the creative processes respectively. We briefly describe two projects; one focused on (artistic) creative artefacts the other on a (scientific) creative process, to highlight some similarities and differences in approach. We then look at a 2- dimensional model of Learning Objectives that uses independent axes of knowledge and (cognitive) processes. This educational framework is then used to cast artefact and process perspectives into a common framework, opening up new possibilities for discussing and comparing creativity between them. Finally, arising from our model of creative processes, we propose a new and broad 4-level hierarchy of computational creativity, which asserts that the highest level of computational creativity involves processes whose creativity is comparable to that of the originating process itself

FlowNet-PET: Unsupervised Learning to Perform Respiratory Motion Correction in PET Imaging

To correct for respiratory motion in PET imaging, an interpretable and unsupervised deep learning technique, FlowNet-PET, was constructed. The network was trained to predict the optical flow between two PET frames from different breathing amplitude ranges. The trained model aligns different retrospectively-gated PET images, providing a final image with similar counting statistics as a non-gated image, but without the blurring effects. FlowNet-PET was applied to anthropomorphic digital phantom data, which provided the possibility to design robust metrics to quantify the corrections. When comparing the predicted optical flows to the ground truths, the median absolute error was found to be smaller than the pixel and slice widths. The improvements were illustrated by comparing against images without motion and computing the intersection over union (IoU) of the tumors as well as the enclosed activity and coefficient of variation (CoV) within the no-motion tumor volume before and after the corrections were applied. The average relative improvements provided by the network were 64%, 89%, and 75% for the IoU, total activity, and CoV, respectively. FlowNet-PET achieved similar results as the conventional retrospective phase binning approach, but only required one sixth of the scan duration. The code and data have been made publicly available (https://github.com/teaghan/FlowNet_PET)