393 research outputs found

    The Traditional Fishery on Deh Cho: An Ethnohistoric and Archaeological Perspective

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    Dene use of the resources of Deh Cho, the preferred Slavey name for the Mackenzie River, in the late pre-contact and early post-contact periods is not well understood. This paper examines the archaeological record of the Mackenzie Valley in relation to a model of Native use of the river, based upon Alexander Mackenzie's observations on the exploitation of the fishery at the first direct contact between Europeans and the Dene along Deh Cho. Use of archaeological data, ethnographic analogy and later historic sources provokes the conclusion that Dene land and river resource use did not drastically change as a result of European contact and the fur trade.Key words: Slavey, Dogrib, Hare, Dene, Athapaskan, fish, Mackenzie River, traditional harvesting, ethnoarchaeology, ethnohistoryMots clés: Slavey, Dogrib, Hare, Déné, Athapaskan, poisson, fleuve Mackenzie, collecte traditionnelle pour la subsistance, ethnoarchéologie, ethnohistoir

    MISPLACED RESOURCES? FACTORS ASSOCIATED WITH COMPUTER LITERACY AMONG END-USERS

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    Some organizations provide a support infrastructure (e.g., information centers, on-line help) and training (e.g., vendor-supplied, one-on-one) to assist end-users and boost the computer literacy of their workforce. In this paper, we explore the efficacy of a support infrastructure, training, and various computer configurations for enhancing the computer literacy of work groups. Data come from a multi-year (1987 to 1989) study of seventy-seven computer-using work groups in the southern California area, which included two interviews with managers and two questionnaires distributed to workers. Analyses showed that none of the measures of training were associated with computer literacy. Only one kind of infrastructure support, obtaining information from a resident expert in the work group, was related to computer literacy. In contrast, many aspects of the configuration of the computer systems were associated with computer literacy. Implications of these provocative findings for the management of end-user computing are discussed

    Small Towns and Welfare Reform: Iowa Case Studies of Families and Communities

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    Since passage of the Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA) in 1996, public discussion of welfare reform and most research efforts to assess the effects of new policies have focused on urban areas. Major studies and frequent newspaper headlines have portrayed the dimensions of welfare reform in Los Angeles, Miami, Boston, and other urban settings (e.g., Burton et al. 1998; Quint et al. 1999). Little attention is being paid to the consequences of the new policies for rural families and communities.This book chapter is published as 2002 Fletcher, C. N., Flora, J. L., Gaddis, B. J., Winter, M., and J. S. Litt. “Small Towns and Welfare Reform: Iowa Case Studies of Families and Communities.” In Bruce A. Weber, Greg J. Duncan and Leslie A. Whitener (eds.) Rural Dimensions of Welfare Reform: Welfare, Food Assistance and Poverty in Rural America (pp. 201-229). Kalamazoo, MI: Upjohn Press. 10.17848/9781417508884 </p

    Macroscopic Quantum Tunneling of Ferromagnetic Domain Walls

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    Quantum tunneling of domain walls out of an impurity potential in a mesoscopic ferromagnetic sample is investigated. Using improved expressions for the domain wall mass and for the pinning potential, we find that the cross-over temperature between thermal activation and quantum tunneling is of a different functional form than found previously. In materials like Ni or YIG, the crossover temperatures are around 5 mK. We also find that the WKB exponent is typically two orders of magnitude larger than current estimates. The sources for these discrepancies are discussed, and precise estimates for the transition from three-dimensional to one-dimensional magnetic behavior of a wire are given. The cross-over temperatures from thermal to quantum transitions and tunneling rates are calculated for various materials and sample sizes.Comment: 10 pages, 2 postscript figures, REVTe

    Classical information deficit and monotonicity on local operations

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    We investigate classical information deficit: a candidate for measure of classical correlations emerging from thermodynamical approach initiated in [Phys. Rev. Lett 89, 180402]. It is defined as a difference between amount of information that can be concentrated by use of LOCC and the information contained in subsystems. We show nonintuitive fact, that one way version of this quantity can increase under local operation, hence it does not possess property required for a good measure of classical correlations. Recently it was shown by Igor Devetak, that regularised version of this quantity is monotonic under LO. In this context, our result implies that regularization plays a role of "monotoniser".Comment: 6 pages, revte

    Evaluating the systemic right ventricle by CMR: the importance of consistent and reproducible delineation of the cavity

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    Contains fulltext : 70334.pdf (publisher's version ) (Open Access)BACKGROUND: The method used to delineate the boundary of the right ventricle (RV), relative to the trabeculations and papillary muscles in cardiovascular magnetic resonance (CMR) ventricular volume analysis, may matter more when these structures are hypertrophied than in individuals with normal cardiovascular anatomy. This study aimed to compare two methods of cavity delineation in patients with systemic RV. METHODS: Twenty-nine patients (mean age 34.7 +/- 12.4 years) with a systemic RV (12 with congenitally corrected transposition of the great arteries (ccTGA) and 17 with atrially switched (TGA) underwent CMR. We compared measurements of systemic RV volumes and function using two analysis protocols. The RV trabeculations and papillary muscles were either included in the calculated blood volume, the boundary drawn immediately within the apparently compacted myocardial layer, or they were manually outlined and excluded. RV stroke volume (SV) calculated using each method was compared with corresponding left ventricular (LV) SV. Additionally, we compared the differences in analysis time, and in intra- and inter-observer variability between the two methods. Paired samples t-test was used to test for differences in volumes, function and analysis time between the two methods. Differences in intra- and inter-observer reproducibility were tested using an extension of the Bland-Altman method. RESULTS: The inclusion of trabeculations and papillary muscles in the ventricular volume resulted in higher values for systemic RV end diastolic volume (mean difference 28.7 +/- 10.6 ml, p < 0.001) and for end systolic volume (mean difference 31.0 +/- 11.5 ml, p < 0.001). Values for ejection fraction were significantly lower (mean difference -7.4 +/- 3.9%, p < 0.001) if structures were included. LV SV did not differ significantly from RV SV for both analysis methods (p = NS). Including structures resulted in shorter analysis time (p < 0.001), and showed better inter-observer reproducibility for ejection fraction (p < 0.01). CONCLUSION: The choice of method for systemic RV cavity delineation significantly affected volume measurements, given the CMR acquisition and analysis systems used. We recommend delineation outside the trabeculations for routine clinical measurements of systemic RV volumes as this approach took less time and gave more reproducible measurements

    Assessing the effects of embedding resins on carbonate stable and clumped isotope analyses

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    Rationale: Embedding resins are widely used to fix carbonates for high-precision sample preparation and high-resolution sampling. However, these embedding materials are difficult to remove after sample preparation and are known to affect the accuracy of carbonate stable isotope analyses. Nevertheless, their impact on clumped isotope analysis, which is particularly sensitive to contamination artifacts, has so far not been tested. The observation that running resin-containing samples decreased the reproducibility of clumped isotope values for internal laboratory carbonate standards and increased the external standard deviation (SD 0.061–0.088‰) compared to the long-term observations (0.034‰), prompted us to set up an experiment to test the influence of resin addition on instrument performance. Methods: Here we analyzed the stable and clumped isotope composition of a pure calcium carbonate standard (ETH-4) mixed with three types of embedding resins in 2:1 and 1:1 proportions. Our aim was to assess how resin addition affects isotope analyses. Results: We found that none of the stable isotopic values were significantly different. The ÎŽ13C values were −10.22 ± 0.07‰ (mean ± SD) for pure ETH-4, while the ÎŽ13C values of ETH-4 mixed with embedding resins in 2:1 and 1:1 proportions were −10.21 ± 0.06‰ and −10.18 ± 0.06‰, respectively (p > 0.05). The ÎŽ18O values were −18.82 ± 0.11‰ for pure ETH-4 versus −18.81 ± 0.09‰ and −18.82 ± 0.08‰ for 2:1 and 1:1 ETH-4:resin mixtures, respectively (p > 0.05). Given the large uncertainty in our results, we did not find significant differences between different mixtures in the carbonate clumped isotope values (Δ47), with 0.458 ± 0.107‰, 0.464 ± 0.086‰, and 0.417 ± 0.089‰ in pure ETH-4 and ETH-4 with 2:1 and 1:1 resin mixtures, respectively (p > 0.05). However, a resin-related bias in the results might be masked by the large uncertainty. The measured ETH-4 values in our study are similar to the InterCarb values (ÎŽ13C = −10.20‰, ÎŽ18O = −18.81‰, Δ47 = 0.450‰, InterCarb-Carbon Dioxide Equilibrium Scale). However, the external SD of Δ47 in sessions measuring ETH-4 with resins is higher than in sessions without deliberate resin addition for the same measuring period. Conclusions: We find that the potential contamination from the resin addition leads to a larger variability for Δ47 values in sessions measuring ETH-4 including resins. We therefore recommend purification of embedded samples using a contamination trap with Porapak prior to analysis, if possible, or avoiding resins during sample preparation and workup, as well as monitoring the measurement quality during and after sessions with samples containing embedding resins

    On asymptotic continuity of functions of quantum states

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    A useful kind of continuity of quantum states functions in asymptotic regime is so-called asymptotic continuity. In this paper we provide general tools for checking if a function possesses this property. First we prove equivalence of asymptotic continuity with so-called it robustness under admixture. This allows us to show that relative entropy distance from a convex set including maximally mixed state is asymptotically continuous. Subsequently, we consider it arrowing - a way of building a new function out of a given one. The procedure originates from constructions of intrinsic information and entanglement of formation. We show that arrowing preserves asymptotic continuity for a class of functions (so-called subextensive ones). The result is illustrated by means of several examples.Comment: Minor corrections, version submitted for publicatio

    Temperature Dependence of Clumped Isotopes (∆47) in Aragonite

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    Clumped isotope thermometry can independently constrain the formation temperatures of carbonates, but a lack of precisely temperature-controlled calibration samples limits its application on aragonites. To address this issue, we present clumped isotope compositions of aragonitic bivalve shells grown under highly controlled temperatures (1–18°C), which we combine with clumped isotope data from natural and synthetic aragonites from a wide range of temperatures (1–850°C). We observe no discernible offset in clumped isotope values between aragonitic foraminifera, mollusks, and abiogenic aragonites or between aragonites and calcites, eliminating the need for a mineral-specific calibration or acid fractionation factor. However, due to non-linear behavior of the clumped isotope thermometer, including high-temperature (>100°C) datapoints in linear clumped isotope calibrations causes them to underestimate temperatures of cold (1–18°C) carbonates by 2.7 ± 2.0°C (95% confidence level). Therefore, clumped isotope-based paleoclimate reconstructions should be calibrated using samples with well constrained formation temperatures close to those of the samples
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