Growth Characteristics and Lipid Metabolism of Cultured Migratory Bird Skeletal Muscle Cells

Diets rich in n-3 polyunsaturated fatty acids (PUFA) may alter the muscle metabolism of migratory birds, improving their endurance performance. I established and validated for the first time in vitro muscle models of a migratory songbird (yellow-rumped warbler, Setophaga coronata coronata) and shorebird (sanderling, Calidris alba). To evaluate the role of n-3 PUFA in improving fatty acid metabolism in migratory bird muscle, I measured metabolic outcomes following n-3 PUFA supplementation in these two avian cell types and a murine (Mus musculus, C2C12) cell line. PUFA supplementation in C2C12 cells increased metabolic transcription factor expression and increased mitochondrial respiratory chain efficiency. Migrant bird muscle cells did not display the same changes in transcriptional signaling, but sanderling cells increased basal and maximal oxygen consumption with n-3 PUFA supplementation. This research provides support for the hypothesis that n-3 PUFA increase aerobic capacity of a migrant sandpiper and efficiency in mammalian skeletal muscle

Influence of human pressures on large river structure and function

A large river study was conducted as part of the Cross Departmental Research Pool (CDRP) ecological integrity project to (i) provide an overview of the macroinvertebrate faunas of large rivers, including those in deep-water habitats, and (ii) to elucidate links between these faunas, river function and anthropogenic stressors. Eleven sites on 6th-order or 7th-order rivers were sampled; four in the South Island and seven in the North Island. We measured (i) macroinvertebrate communities colonising wood, riffles (where present), littoral habitats (1.5 m deep) (ii) ecosystem metabolism using a single-station open-channel approach based on natural changes in dissolved oxygen concentration over a 24-hour period, and (iii) wood and cellulose breakdown. Relationships were investigated between these response variables and reach-scale assessments of habitat quality, underlying upstream and segment environmental variables provided in the Freshwater Environments of New Zealand (FWENZ) database, and anthropogenic pressure variables provided by the Waters of National Importance (WONI) database

Extraordinarily rapid proliferation of cultured muscle satellite cells from migratory birds

Migratory birds experience bouts of muscle growth and depletion as they prepare for, and undertake prolonged flight. Our studies of migratory bird muscle physiology in vitro led to the discovery that sanderling (Calidris alba) muscle satellite cells proliferate more rapidly than other normal cell lines. Here we determined the proliferation rate of muscle satellite cells isolated from five migratory species (sanderling; ruff, Calidris pugnax; western sandpiper, Calidris mauri; yellow-rumped warbler, Setophaga coronata; Swainson\u27s thrush, Catharus ustulatus) from two families (shorebirds and songbirds) and with different migratory strategies. Ruff and sanderling satellite cells exhibited rapid proliferation, with population doubling times of 9.3 ± 1.3 and 11.4 ± 2 h, whereas the remaining species\u27 cell doubling times were greater than or equal to 24 h. The results indicate that the rapid proliferation of satellite cells is not associated with total migration distance but may be related to flight bout duration and interact with lifespan

Testing Whether Camera Presence Influences Habitat Specific Predation Pressure on Artificial Shorebird Nests in the Arctic

When monitoring the breeding ecology of birds, the causes and times of nest failure can be difficult to determine. Cameras placed near nests allow for accurate monitoring of nest fate, but their presence may increase the risk of predation by attracting predators, leading to biased results. The relative influence of cameras on nest predation risk may also depend on habitat because predator numbers or behaviour can change in response to the availability or accessibility of nests. We evaluated the impact of camera presence on the predation rate of artificial nests placed within mesic tundra habitats used by Arctic-breeding shorebirds. We deployed 94 artificial nests, half with cameras and half without, during the shorebird-nesting season of 2015 in the East Bay Migratory Bird Sanctuary, Nunavut. Artificial nests were distributed evenly across sedge meadow and supratidal habitats typically used by nesting shorebirds. We used the Cox proportional hazards model to assess differential nest survival in relation to camera presence, habitat type, placement date, and all potential interactions. Artificial nests with cameras did not experience higher predation risk than those without cameras. Predation risk of artificial nests was related to an interaction between habitat type and placement date. Nests deployed in sedge meadows and in supratidal habitats later in the season were subject to a higher risk of predation than those deployed in supratidal habitats early in the season. These differences in predation risk are likely driven by the foraging behaviour of Arctic fox (Vulpes lagopus), a species that accounted for 81% of observed predation events in this study. Arctic fox prey primarily on Arvicoline prey and goose eggs at this site and take shorebird nests opportunistically, perhaps more often later in the season when their preferred prey becomes scarcer. This study demonstrates that, at this site, cameras used for nest monitoring do not influence predation risk. Evaluating the impact of cameras on predation risk is critical prior to their use, as individual study areas may differ in terms of predator species and behaviour.Lors de la surveillance de l’écologie de reproduction des oiseaux, les causes et les périodes de défaillance des nids peuvent être difficiles à déterminer. Des caméras placées près des nids permettent une surveillance précise du sort des nids, mais leur présence peut augmenter le risque de prédation en attirant les prédateurs, ce qui entraîne des résultats biaisés. L’influence relative des caméras sur le risque de prédation des nids peut également dépendre de l’habitat, car le nombre ou le comportement des prédateurs peut changer en fonction de la disponibilité ou de l’accessibilité des nids. Nous avons évalué l’impact de la présence de caméras sur le taux de prédation des nids artificiels placés dans les habitats de la toundra mésique utilisés par les limicoles se reproduisant dans l’Arctique. Nous avons installé 94 nids artificiels, la moitié avec des caméras et l’autre moitié sans caméras, pendant la saison de nidification des limicoles de 2015 dans le Refuge d’oiseaux migrateurs de la baie Est, au Nunavut. Les nids artificiels étaient répartis uniformément dans les cariçaies et les habitats supratidaux généralement utilisés par les limicoles nicheurs. Nous avons utilisé le modèle à risques proportionnels de Cox pour évaluer la survie différentielle des nids en fonction de la présence de caméras, du type d’habitat, de la date d’installation des caméras et de toutes les interactions potentielles. Les nids artificiels équipés de caméras ne présentaient pas de risque de prédation plus élevé que ceux sans caméras. Le risque de prédation des nids artificiels était lié à une interaction entre le type d’habitat et la date d’installation des caméras. Plus tard dans la saison, les nids placés dans les cariçaies et dans les habitats supratidaux ont fait l’objet d’un risque de prédation plus élevé que ceux des habitats supratidaux en début de saison. Ces différences de risque de prédation sont probablement attribuables au comportement d’alimentation du renard arctique (Vulpes lagopus), une espèce qui représentait 81 % des événements de prédation observés dans cette étude. Le renard arctique se nourrit principalement d’arvicolinés et d’oeufs d’oie sur ce site, et s’empare des nids de limicoles de manière opportuniste, peut-être plus souvent plus tard dans la saison, lorsque ses proies préférées se font plus rares. Cette étude démontre que, sur ce site, les caméras servant à la surveillance des nids n’influencent pas le risque de prédation. Il est essentiel d’évaluer l’impact des caméras sur le risque de prédation avant leur utilisation, car chacune des zones étudiées peut différer sur le plan des espèces de prédateurs et des comportements

Multi-mode coupling wave theory for helically corrugated waveguide

Helically corrugated waveguide has been used in various applications such as gyro-backward wave oscillators, gyro-traveling wave amplifier and microwave pulse compressor. A fast prediction of the dispersion characteristic of the operating eigenwave is very important when designing a helically corrugated waveguide. In this paper, multi-mode coupling wave equations were developed based on the perturbation method. This method was then used to analyze a five-fold helically corrugated waveguide used for X-band microwave compression. The calculated result from this analysis was found to be in excellent agreement with the results from numerical simulation using CST Microwave Studio and vector network analyzer measurements

Development and characterization of a murine hepatoma model expressing hepatitis Cvirus (HCV) non-structural antigens for evaluating HCV vaccines

Hepatitis C (HCV) is a highly prevalent blood-borne virus with infection of 2-3% of world population and high rate of chronicity (\u3e70%) leading to chronic hepatitis, which often progress to cirrhosis and hepatocellular carcinoma. HCV- specific immune responses consisting of CD4 and CD8 T cells and virus neutralizing antibodies have been shown to eliminate HCV infections in humans and chimpanzees. Therefore, vaccines that can induce potent and durable anti-HCV T and B cell responses may have the potential to clear chronic HCV infections. A number of HCV vaccines have been tested clinically with limited success. One of the major limitations in developing effective HCV therapies is the lack of effective and reliable animal models due to the narrow host range of the HCV virus. The study described herein reports the generation of a murine hepatoma cell line expressing HCV non-structural proteins and its use in a metastatic tumor setting to test anti-tumor efficacy of bacterial and viral vector vaccines expressing the HCV non-structural genes. HCV-recombinant hepatoma cells formed large solid-mass tumors when implanted into syngeneic mice, allowing the testing of HCV vaccines for immunogenicity and anti-tumor efficacy. Using this model, we tested the therapeutic potential of recombinant anti-HCV-specific vaccines based on two fundamentally different attenuated pathogen vaccine systems - attenuated Salmonella and recombinant adenoviral vector based vaccine. Attenuated Salmonella secreting HCV antigens limited growth of the HCV-recombinant tumors when used in a therapeutic vaccination setting. The inhibition of tumor growth by Salmonella vector-based vaccines was significantly reduced in mice co-injected with an anti-CD8 antibody, suggesting a role by CD8+ cells in the vaccine efficacy. The model was also used to compare replication deficient and replication-competent but non-infectious adenoviral vectors expressing non-structural HCV antigens. Results showed overall greater survival and reduced weight loss with the replication-competent vector compared to the non-replicating vector. Our results demonstrate the novel recombinant murine hepatoma model expressing HCV non-structural antigens as a useful model for evaluating therapeutic vaccines against HCV. Vaccines that are capable of inducing potent anti-HCV immune responses that are capable of controlling aggressive and metastatic tumor growth in this model would likely have the potential to control chronic viral infections such as HCV. This novel approach is particularly interesting for the development of therapeutic vaccines

Finite temperature quantum simulation of stabilizer Hamiltonians

We present a scheme for robust finite temperature quantum simulation of stabilizer Hamiltonians. The scheme is designed for realization in a physical system consisting of a finite set of neutral atoms trapped in an addressable optical lattice that are controllable via 1- and 2-body operations together with dissipative 1-body operations such as optical pumping. We show that these minimal physical constraints suffice for design of a quantum simulation scheme for any stabilizer Hamiltonian at either finite or zero temperature. We demonstrate the approach with application to the abelian and non-abelian toric codes.Comment: 13 pages, 2 figure

A Review of Target Mass Corrections

With recent advances in the precision of inclusive lepton--nuclear scattering experiments, it has become apparent that comparable improvements are needed in the accuracy of the theoretical analysis tools. In particular, when extracting parton distribution functions in the large-x region, it is crucial to correct the data for effects associated with the nonzero mass of the target. We present here a comprehensive review of these target mass corrections (TMC) to structure functions data, summarizing the relevant formulas for TMCs in electromagnetic and weak processes. We include a full analysis of both hadronic and partonic masses, and trace how these effects appear in the operator product expansion and the factorized parton model formalism, as well as their limitations when applied to data in the x->1 limit. We evaluate the numerical effects of TMCs on various structure functions, and compare fits to data with and without these corrections.Comment: 41 pages, 13 figures; minor updates to match published versio