Zooarchaeology of a Focal Resource : Dietary Importance of Beluga Whales to the Precontact Mackenzie Inuit

Ethnohistoric records indicate that the economy of early historic Mackenzie Inuit was centred on the summer hunt for beluga whales (Delphinapterus leucas). However, no systematic attempt has been made to quantify the dietary importance of beluga whales to earlier, precontact-period Mackenzie Inuit societies. This issue is addressed herein through analysis of over 2000 beluga bones recovered from a semisubterranean house at Gupuk, a Mackenzie Inuit archaeological site on the East Channel of the Mackenzie River. The amount of meat and fat available from beluga whales is compared to that from all other prey species at the site to assess the relative dietary contribution of each taxon. The results indicate that beluga whales were a truly focal resource in the local economy, probably providing over half of the food available to residents of Gupuk and other communities in the Mackenzie Delta for at least half of each year.Key words: beluga whale, white whale, Delphinapterus leucas, Gupuk, Kittigazuit, Mackenzie Inuit, Inuvialuit, Mackenzie Delta, zooarchaeology, archaeologyLes relevés ethnohistoriques indiquent que l'économie des Inuit du Mackenzie du début de l'époque historique était centrée sur la chasse estivale au bélouga (Delphinapterus leucas). Aucun essai systématique n'a cependant été réalisé dans le but de quantifier l'importance alimentaire du bélouga pour les anciennes sociétés inuits du Mackenzie d'avant le contact avec les Européens. Grâce à l'analyse de plus de 2000 os de bélougas récupérés dans une habitation semi-souterraine de Gupuk, site archéologique inuit du Mackenzie sur le chenal est de la rivière Mackenzie, on a pu comparer la quantité de viande et de gras venant du bélouga à celle de toutes les autres espèces de proies sur le site afin d'évaluer la contribution alimentaire relative de chaque taxon. Les résultats indiquent que le bélouga était véritablement une ressource primordiale dans l'économie locale, fournissant probablement plus de la moitié de la nourriture disponible aux résidents de Gupuk et des autres communautés du delta du Mackenzie pendant au moins six mois de l'année.Mots clés: bélouga, baleine blanche, Delphinapterus leucas, Gupuk, Kittigazuit, Inuit du Mackenzie, Inuvialuit, delta du Mackenzie, zoo-archéologie, archéologi

Analysis of the Early-Time Optical Spectra of SN 2011fe in M101

The nearby Type Ia supernova SN 2011fe in M101 (cz=241 km s^-1) provides a unique opportunity to study the early evolution of a normal Type Ia supernova, its compositional structure, and its elusive progenitor system. We present 18 high signal-to-noise spectra of SN 2011fe during its first month beginning 1.2 days post-explosion and with an average cadence of 1.8 days. This gives a clear picture of how various line-forming species are distributed within the outer layers of the ejecta, including that of unburned material (C+O). We follow the evolution of C II absorption features until they diminish near maximum light, showing overlapping regions of burned and unburned material between ejection velocities of 10,000 and 16,000 km s^-1. This supports the notion that incomplete burning, in addition to progenitor scenarios, is a relevant source of spectroscopic diversity among SNe Ia. The observed evolution of the highly Doppler-shifted O I 7774 absorption features detected within five days post-explosion indicate the presence of O I with expansion velocities from 11,500 to 21,000 km s^-1. The fact that some O I is present above C II suggests that SN 2011fe may have had an appreciable amount of unburned oxygen within the outer layers of the ejecta

Editorial: Long-Term Perspectives on Circumpolar Social-Ecological Systems

Modern climate change is having profound environmental impacts at the world's higher latitudes, leading to the disappearance of sea ice, the melting of permafrost and the northward shift of major biogeographic zones. These changing conditions have consequences for contemporary Arctic Indigenous peoples and their traditional lifeways. As planning and mitigation efforts intensify, there is renewed interest in looking back through time to understand how past Arctic societies were able to maintain a long-term—and often highly-resilient —presence in these ever-changing ecosystems. Of particular interest is how past groups coped with earlier changes in climate, both shorter-term “shocks” as well as longer-term up- and downturns in temperatures. A number of recent publications have highlighted the abundance of high-resolution and human-scale data that archaeology is uniquely positioned to contribute to this discussion (Riede, 2014; Jackson et al., 2018; Fitzhugh et al., 2018). So far, however, the practical integration of such long-term “paleo-” perspectives on specific future-orientated planning and management efforts has been limited. For example, the Arctic Council's Arctic Resilience Report (2016)—an in-depth comparative analysis of fragility and resilience in numerous local circumpolar social-ecological systems—acknowledges the importance of “deep history”, and the role of flexibility and traditional knowledge, while the chronological coverage of all 25 local case-studies remains firmly rooted in the present and very recent historical past. The overarching aim of this Special Issue is to explore the gap in knowledge between archaeological understandings of long-term Arctic adaptations and the practical application of these insights to the future-oriented challenges of sustainability and cultural survival. The first objective is to illustrate the wealth and diversity of archaeological research that is currently taking place in both the northern and southern polar regions. The issue showcases a selection of case-studies focusing on long-term human-environment interactions, integrating archaeological, climatic and paleoecological datasets. A wide range of insights emerge in terms of cultural responses to specific climatic fluctuations, but also in terms of longer-term cultural trajectories, including major shifts in settlement, subsistence, demography and interaction networks, all of which can be understood in terms of fragility and resilience in particular social-ecological systems. Another objective of the volume is to stimulate reflection and debate about what these archaeological datasets—and the long-term insights that emerge—can contribute to future planning and mitigation efforts. Seventeen papers in this issue “look back”, examining human-environment interactions in three regions: Arctic Eurasia; Arctic North America and Greenland; and Sub-Antarctic South America. Conversely, three papers “look ahead”, exploring emerging challenges and future implications. We conclude this editorial with a series of recommendations – or “action points” – that are addressed to the wider interdisciplinary research community

Gate fidelity and coherence of an electron spin in a Si/SiGe quantum dot with micromagnet

The gate fidelity and the coherence time of a qubit are important benchmarks for quantum computation. We construct a qubit using a single electron spin in a Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field from a micromagnet. We measure an average single-qubit gate fidelity of $\approx$ 99$\%$ using randomized benchmarking, which is consistent with dephasing from the slowly evolving nuclear spins in substrate. The coherence time measured using dynamical decoupling extends up to $\approx$ 400 $\mu$s for 128 decoupling pulses, with no sign of saturation. We find evidence that the coherence time is limited by noise in the 10 kHz $-$ 1 MHz range, possibly because charge noise affecting the spin via the micromagnet gradient. This work shows that an electron spin in a Si/SiGe quantum dot is a good candidate for quantum information processing as well as for a quantum memory, even without isotopic purification

Two-axis control of a singlet-triplet qubit with an integrated micromagnet

The qubit is the fundamental building block of a quantum computer. We fabricate a qubit in a silicon double quantum dot with an integrated micromagnet in which the qubit basis states are the singlet state and the spin-zero triplet state of two electrons. Because of the micro magnet, the magnetic field difference $\Delta B$ between the two sides of the double dot is large enough to enable the achievement of coherent rotation of the qubit's Bloch vector about two different axes of the Bloch sphere. By measuring the decay of the quantum oscillations, the inhomogeneous spin coherence time $T_{2}^{*}$ is determined. By measuring $T_{2}^{*}$ at many different values of the exchange coupling $J$ and at two different values of $\Delta B$, we provide evidence that the micromagnet does not limit decoherence, with the dominant limits on $T_{2}^{*}$ arising from charge noise and from coupling to nuclear spins.Comment: 10 pages, 9 figure

Widespread deuteration across the IRDC G035.39-00.33

© 2016 The Authors. Infrared Dark Clouds (IRDCs) are cold, dense regions that are usually found within Giant Molecular Clouds. Ongoing star formation within IRDCs is typically still deeply embedded within the surrounding molecular gas. Characterizing the properties of relatively quiescent IRDCs may therefore help us to understand the earliest phases of the star formation process. Studies of local molecular clouds have revealed that deuterated species are enhanced in the earliest phases of star formation. In this paper, we test this towards IRDC G035.39-00.33. We present an 80 arcsec by 140 arcsec map of the J = 2 → 1 transition of N2D+, obtained with the Institut de Radioastronomie Millimétrique 30 m telescope telescope. We find that N2D+ is widespread throughout G035.39-00.33. Complementary observations of N2H+ (1 - 0) are used to estimate the deuterium fraction, DN2H+ frac ≡ N(N2D+)/N(N2H+). We report a mean DN2H+ frac = 0.04 ± 0.01, with a maximum of DN2H+ frac = 0.09 ± 0.02. The mean deuterium fraction is ~3 orders of magnitude greater than the interstellar [D]/[H] ratio. High angular resolution observations are required to exclude beam dilution effects of compact deuterated cores. Using chemical modelling, we find that the average observed values of DN2H+ frac are in agreement with an equilibrium deuterium fraction, given the general properties of the cloud. This implies that the IRDC is at least ~3 Myr old, which is ~8 times longer than the mean free-fall time of the observed deuterated region

A programmable two-qubit quantum processor in silicon

With qubit measurement and control fidelities above the threshold of fault-tolerance, much attention is moving towards the daunting task of scaling up the number of physical qubits to the large numbers needed for fault tolerant quantum computing. Here, quantum dot based spin qubits may offer significant advantages due to their potential for high densities, all-electrical operation, and integration onto an industrial platform. In this system, the initialisation, readout, single- and two-qubit gates have been demonstrated in various qubit representations. However, as seen with other small scale quantum computer demonstrations, combining these elements leads to new challenges involving qubit crosstalk, state leakage, calibration, and control hardware which provide invaluable insight towards scaling up. Here we address these challenges and demonstrate a programmable two-qubit quantum processor in silicon by performing both the Deutsch-Josza and the Grover search algorithms. In addition, we characterise the entanglement in our processor through quantum state tomography of Bell states measuring state fidelities between 85-89% and concurrences between 73-80%. These results pave the way for larger scale quantum computers using spins confined to quantum dots

Dynamic scaling for 2D superconductors, Josephson junction arrays and superfluids

The value of the dynamic critical exponent $z$ is studied for two-dimensional superconducting, superfluid, and Josephson Junction array systems in zero magnetic field via the Fisher-Fisher-Huse dynamic scaling. We find $z\simeq5.6\pm0.3$, a relatively large value indicative of non-diffusive dynamics. Universality of the scaling function is tested and confirmed for the thinnest samples. We discuss the validity of the dynamic scaling analysis as well as the previous studies of the Kosterlitz-Thouless-Berezinskii transition in these systems, the results of which seem to be consistent with simple diffusion ($z=2$). Further studies are discussed and encouraged.Comment: 19 pages in two-column RevTex, 8 embedded EPS figure