Transitions of social-ecological subsistence systems in the Arctic

Transitions of social-ecological systems (SES) expose governance systems to new challenges. This is particularly so in the Arctic where resource systems are increasingly subjected to global warming, industrial development and globalization which subsequently alter the local SES dynamics. Based on common-pool resource theory, we developed a dynamic conceptual model explaining how exogenous drivers might alter a traditional subsistence system from a provisioning to an appropriation actions situation. In a provisioning action situation the resource users do not control the resource level but adapt to the fluctuating availability of resources, and the collective challenge revolve around securing the subsistence in the community. An increased harvest pressure enabled by exogenous drivers could transform the SES to an appropriation action situation where the collective challenge has changed to avoid overuse of a common-pool resource. The model was used as a focal lens to investigate the premises for broad-scale transitions of subsistence-oriented SESs in Arctic Alaska, Canada and Greenland. We synthesized data from documents, official statistics and grey and scientific literature to explore the different components of our model. Our synthesis suggests that the traditional Arctic subsistence SESs mostly comply with a provisioning action situation. Despite population growth and available technology; urbanization, increased wage labor and importation of food have reduced the resource demand, and we find no evidence for a broad-scale transition to an appropriation action situation throughout the Western Arctic. However, appropriation challenges have emerged in some cases either as a consequence of commercialization of the resource or by severely reduced resource stocks due to various exogenous drivers. Future transitions of SESs could be triggered by the emergence of commercial local food markets and Arctic warming. In particular, Arctic warming is an intensifying exogenous driver that is threatening many important Arctic wildlife resources inflicting increased appropriation challenges to the governance of local harvest.Ye

Polar Bear Conservation in Canada: Defining the Policy Problems

Conservation of polar bears (Ursus maritimus) in Canada is based on the goals and principles of the 1973 International Agreement on the Conservation of Polar Bears and Their Habitat, and has long been considered an exemplar of science-based wildlife management. However, accelerating social and ecological changes in the Arctic raise questions about the polar bear management regime’s ability to adapt successfully to new challenges. We apply the analytic framework of the policy sciences to develop a comprehensive orientation to this evolving situation, and we suggest possible ways to define and advance shared goals of stakeholders and other participants. We conclude that the decision process in polar bear management does not sufficiently foster identification and securing of common interests among participants who express multiple, competing perspectives in an arena that has been increasingly fragmented and symbolically charged by issues such as the recent listing of polar bears under the U.S. Endangered Species Act. The fundamental challenge for polar bear conservation in Canada is to design a better decision process so that it can constructively reconcile the various perspectives, demands, and expectations of stakeholders.Au Canada, la conservation des ours polaires (Ursus maritimus) respecte les objectifs et les principes de l’Accord international sur la conservation des ours blancs et leur habitat de 1973, qui est considéré depuis longtemps comme un modèle de gestion de la faune fondée sur la science. Cependant, l’évolution de plus en plus rapide des changements d’ordre social et écologique dans l’Arctique a pour effet de soulever des questions sur l’aptitude du régime de gestion de l’ours polaire à bien s’adapter aux nouveaux défis. Nous utilisons le cadre de référence analytique de la science des politiques pour aboutir à une orientation exhaustive de cette situation en pleine évolution, et nous suggérons des manières possibles de définir et de formuler des objectifs partagés par les parties prenantes et d’autres participants. Nous concluons que le processus de décision en matière de gestion de l’ours polaire n’encourage pas suffisamment l’identification et l’engagement d’intérêts communs entre les participants qui expriment des perspectives multiples et concurrentes dans un domaine de plus en plus fragmenté et symboliquement caractérisé par des enjeux tels que la liste récente d’ours polaires en vertu de la loi américaine sur les espèces en voie de disparition (U.S. Endangered Species Act). Le défi fondamental en ce qui a trait à la conservation des ours polaires au Canada consiste à concevoir un meilleur processus de décision pouvant réconcilier, de manière constructive, les diverses perspectives, exigences et attentes des parties prenantes

Laser Guide Star for Large Segmented-Aperture Space Telescopes, Part I: Implications for Terrestrial Exoplanet Detection and Observatory Stability

Precision wavefront control on future segmented-aperture space telescopes presents significant challenges, particularly in the context of high-contrast exoplanet direct imaging. We present a new wavefront control architecture that translates the ground-based artificial guide star concept to space with a laser source aboard a second spacecraft, formation flying within the telescope field-of-view. We describe the motivating problem of mirror segment motion and develop wavefront sensing requirements as a function of guide star magnitude and segment motion power spectrum. Several sample cases with different values for transmitter power, pointing jitter, and wavelength are presented to illustrate the advantages and challenges of having a non-stellar-magnitude noise limited wavefront sensor for space telescopes. These notional designs allow increased control authority, potentially relaxing spacecraft stability requirements by two orders of magnitude, and increasing terrestrial exoplanet discovery space by allowing high-contrast observations of stars of arbitrary brightness.Comment: Submitted to A

Selective Use of Pericardial Window and Drainage as Sole Treatment for Hemopericardium from Penetrating Chest Trauma

Background Penetrating cardiac injuries (PCIs) are highly lethal, and a sternotomy is considered mandatory for suspected PCI. Recent literature suggests pericardial window (PCW) may be sufficient for superficial cardiac injuries to drain hemopericardium and assess for continued bleeding and instability. This study objective is to review patients with PCI managed with sternotomy and PCW and compare outcomes. Methods All patients with penetrating chest trauma from 2000 to 2016 requiring PCW or sternotomy were reviewed. Data were collected for patients who had PCW for hemopericardium managed with only pericardial drain, or underwent sternotomy for cardiac injuries grade 1–3 according to the American Association for the Surgery of Trauma (AAST) Cardiac Organ Injury Scale (OIS). The PCW+drain group was compared with the Sternotomy group using Fisher’s exact and Wilcoxon rank-sum test with P\u3c0.05 considered statistically significant. Results Sternotomy was performed in 57 patients for suspected PCI, including 7 with AAST OIS grade 1–3 injuries (Sternotomy group). Four patients had pericardial injuries, three had partial thickness cardiac injuries, two of which were suture-repaired. Average blood drained was 285mL (100–500 mL). PCW was performed in 37 patients, and 21 had hemopericardium; 16 patients proceeded to sternotomy and 5 were treated with pericardial drainage (PCW+drain group). All PCW+drain patients had suction evacuation of hemopericardium, pericardial lavage, and verified bleeding cessation, followed by pericardial drain placement and admission to intensive care unit (ICU). Average blood drained was 240mL (40–600 mL), and pericardial drains were removed on postoperative day 3.6 (2–5). There was no significant difference in demographics, injury mechanism, Revised Trauma Score exploratory laparotomies, hospital or ICU length of stay, or ventilator days. No in-hospital mortality occurred in either group. Conclusions Hemodynamically stable patients with penetrating chest trauma and hemopericardium may be safely managed with PCW, lavage and drainage with documented cessation of bleeding, and postoperative ICU monitoring. Level of evidence Therapeutic study, level IV

Mutagenesis of Trichoderma reesei endoglucanase I: impact of expression host on activity and stability at elevated temperatures.

BackgroundTrichoderma reesei is a key cellulase source for economically saccharifying cellulosic biomass for the production of biofuels. Lignocellulose hydrolysis at temperatures above the optimum temperature of T. reesei cellulases (~50°C) could provide many significant advantages, including reduced viscosity at high-solids loadings, lower risk of microbial contamination during saccharification, greater compatibility with high-temperature biomass pretreatment, and faster rates of hydrolysis. These potential advantages motivate efforts to engineer T. reesei cellulases that can hydrolyze lignocellulose at temperatures ranging from 60-70°C.ResultsA B-factor guided approach for improving thermostability was used to engineer variants of endoglucanase I (Cel7B) from T. reesei (TrEGI) that are able to hydrolyze cellulosic substrates more rapidly than the recombinant wild-type TrEGI at temperatures ranging from 50-70°C. When expressed in T. reesei, TrEGI variant G230A/D113S/D115T (G230A/D113S/D115T Tr_TrEGI) had a higher apparent melting temperature (3°C increase in Tm) and improved half-life at 60°C (t1/2 = 161 hr) than the recombinant (T. reesei host) wild-type TrEGI (t1/2 = 74 hr at 60°C, Tr_TrEGI). Furthermore, G230A/D113S/D115T Tr_TrEGI showed 2-fold improved activity compared to Tr_TrEGI at 65°C on solid cellulosic substrates, and was as efficient in hydrolyzing cellulose at 60°C as Tr_TrEGI was at 50°C. The activities and stabilities of the recombinant TrEGI enzymes followed similar trends but differed significantly in magnitude depending on the expression host (Escherichia coli cell-free, Saccharomyces cerevisiae, Neurospora crassa, or T. reesei). Compared to N.crassa-expressed TrEGI, S. cerevisiae-expressed TrEGI showed inferior activity and stability, which was attributed to the lack of cyclization of the N-terminal glutamine in Sc_TrEGI and not to differences in glycosylation. N-terminal pyroglutamate formation in TrEGI expressed in S. cerevisiae was found to be essential in elevating its activity and stability to levels similar to the T. reesei or N. crassa-expressed enzyme, highlighting the importance of this ubiquitous modification in GH7 enzymes.ConclusionStructure-guided evolution of T. reesei EGI was used to engineer enzymes with increased thermal stability and activity on solid cellulosic substrates. Production of TrEGI enzymes in four hosts highlighted the impact of the expression host and the role of N-terminal pyroglutamate formation on the activity and stability of TrEGI enzymes

Inuit Attitudes towards Co-Managing Wildlife in Three Communities in the Kivalliq Region of Nunavut, Canada

We explored Inuit attitudes towards co-managing wildlife in the Kivalliq Region of Nunavut, Canada, working in partnership with the hunters and trappers’ organizations of Igluligaarjuk (Chesterfield Inlet), Tikirarjuaq (Whale Cove), and Qamani’tuaq (Baker Lake). In mixed-methods interviews, study participants in the two coastal communities described dissatisfaction with polar bear (Ursus maritimus) management outcomes, in contrast to a general satisfaction with (or indifference to) the management of other species. Interviewees expressed concern about grizzly bear (Ursus arctos) and, more prominently, caribou (Rangifer tarandus groenlandicus) populations in Qamani’tuaq, the inland community. Researchers have predicted that conflicts specific to polar bear management could lead to regulations being ignored or even defied and endanger the entire system of wildlife co-management. Our results indicate that dissatisfaction over decisions is specific to polar bear management outcomes and does not necessarily apply to the broader system of wildlife co-management. The results suggest that the Nunavut wildlife co-management system is quite functional: polar bear issues aside, Inuit in Qamani’tuaq, Tikirarjuaq, and Igluligaarjuk are largely content with the current functioning of the wildlife co-management regime.Nous avons étudié les attitudes des Inuits à l’égard de la cogestion de la faune dans la région de Kivalliq, au Nunavut, Canada, en collaboration avec les organisations de chasseurs et de trappeurs d’Igluligaarjuk (inlet Chesterfield), de Tikirarjuaq (Whale Cove) et de Qamani’tuaq (Baker Lake). Dans le cadre d’entretiens effectués au moyen de diverses méthodes, les participants à l’étude des deux collectivités côtières ont exprimé leur mécontentement à l’égard des résultats de la gestion de l’ours polaire (Ursus maritimus), comparativement à leur satisfaction générale (ou à leur indifférence) quant à la gestion des autres espèces. Par ailleurs, les personnes interrogées ont exprimé des inquiétudes par rapport aux populations de grizzli (Ursus arctos) et des inquiétudes encore plus grandes par rapport aux populations de caribou (Rangifer tarandus groenlandicus) à Qamani’tuaq, la collectivité intérieure. Selon les chercheurs, les conflits en matière de gestion de l’ours polaire pourraient se traduire par le non-respect ou la non-considération des règlements, et mettre en danger le système de cogestion de la faune dans son ensemble. D’après nos résultats, le mécontentement à l’égard des décisions a précisément trait aux résultats de la gestion des ours polaires et ne concerne pas nécessairement le système général de cogestion de la faune. Selon les résultats, le système de cogestion de la faune du Nunavut est bien fonctionnel : mis à part la question des ours polaires, les Inuits de Qamani’tuaq, de Tikirarjuaq et d’Igluligaarjuk sont en grande partie satisfaits du fonctionnement actuel du régime de cogestion de la faune

Summer Movements of Radio-tagged Arctic Charr (Salvelinus alpinus) in Lake Hazen, Nunavut, Canada

Radiotelemetry was used to determine whether Lake Hazen arctic charr (Salvelinus alpinus) were anadromous and to determine movements of the charr within the lake. In 1995 and 1996, 62 and 55 charr, respectively, were captured, radio-tagged, and released back into the lake. A fixed data acquisition system recorded limited movements of radio-tagged charr in the upper reaches of the Ruggles River, the only outlet from the lake to the sea, in 1995. When movements of radio-tagged charr within Lake Hazen were monitored opportunistically in 1995, most of the relocated charr were found in warmer, more productive waters associated with inflowing streams. No movements of radio-tagged charr in the Ruggles River were recorded in 1996 when the data acquisition system was operated in the lower reaches of the river. These observations supported the conclusions of a study of Lake Hazen charr otolith strontium distribution that Lake Hazen charr were non-anadromous. The Ruggles River may be a detriment to anadromous behaviour because of its length (ca. 29 km), velocity (up to 2.25 m/s), and the year-round presence of aufeis (layered ice buildup). In summer, instead of migrating to the sea to feed, Lake Hazen charr appear to move to feed on abundant prey found in areas where inlet streams enter the lake.On a fait appel à la télémesure pour savoir si l'omble chevalier (Salvelinus alpinus) du lac de Hazen est anadrome et pour connaître ses déplacements dans le lac. On a capturé 62 ombles en 1995 et 55 en 1996 qu'on a munis de radio-émetteurs avant de les relâcher dans le lac. En 1995, un système fixe de collecte de données a enregistré les déplacements restreints des ombles munis de radio-émetteurs dans le cours supérieur de la rivière Ruggles, la seule décharge du lac dans la mer. Quand on a pu vérifier les déplacements de ces ombles dans le lac de Hazen en 1995, la plupart des poissons se trouvaient dans les eaux plus chaudes et plus productives associées à des ruisseaux d'arrivée. En 1996, après qu'un système de collecte de données a été installé dans le cours inférieur de la rivière Ruggles, on n'y a enregistré aucun déplacement des ombles munis de radio-émetteurs. Ces observations viennent étayer une étude sur la distribution du strontium otolithique chez l'omble du lac de Hazen, qui concluait que ce poisson n'était pas anadrome. Il se peut que la rivière Ruggles soit peu propice à un comportement anadrome en raison de sa longueur (env. 29 km), de sa vitesse (jusqu'à 2,25 m/s) et de la présence toute l'année d'un dôme de glace (Aufeishugel). En été, au lieu de migrer vers la mer pour se nourrir, l'omble du lac de Hazen semble se déplacer vers les zones où les ruisseaux se déversent dans le lac et qui contiennent des proies en abondance

Temporal aspects of polar bear occurrences at field camps in Wapusk National Park, Canada

Wapusk National Park, University of Manitoba, University of Saskatchewan, the Social Sciences and Humanities Research Council of Canada, Hudson Bay Helicopters, the Churchill Northern Studies Centre, and EarthRangers.Interaction between polar bears (Ursus maritimus) and people is a growing concern for both bear conservation and human safety in a warming Arctic climate. Consequently, the importance of monitoring temporal trends in the proximity of polar bears to people has become critical in managing human-polar bear conflicts. Such concerns are acute in Wapusk National Park in Manitoba, Canada on the Western Hudson Bay coast, where we deployed 18 camera traps at three remote field camps from 2010–2014 (~22,100 camera-days) to monitor the frequency and timing of bears’ visits to those facilities. Following seasonal breakup of Hudson Bay’s sea ice polar bear occurrences at these camps increased throughout the summer and into fall (low in May–July and increasing sharply through August–November and then approaching zero in December when Hudson Bay freezes). We quantified age and sex class and estimated body condition of bears visiting the camps: adult males were most prevalent at Nester One camp close to where adult males congregate at Cape Churchill, whereas the two camps farther south were visited more frequently by females with dependent young, likely traveling to and from a known maternal denning area. Few subadults were observed. As expected, body condition scores declined throughout the on-shore season. Our method of monitoring polar bear occurrence on shore is robust, cost-effective, and non-invasive, and so may provide an economical complement to data gathered through more conventional techniques