3,962 research outputs found
Review of \u3ci\u3eGathering Places: Aboriginal and Fur Trade Histories.\u3c/i\u3e Edited by Carolyn Podruchny and Laura Peers.
Gathering Places honors Jennifer S.H. Brown, a leading figure in the Aboriginal history of the Hudson Bay drainage basin. The ten essays and introduction deal with Natives and Native history in the region of Hudson Bay, and there is the influence of Professor Brown; otherwise the topics are diverse. The papers have been grouped into several themes, but broadly speaking there are two types of essays. Some use novel as well as more traditional approaches to shed light on aspects of the Aboriginal experience; the others are methodological, dealing with the writing of First Nations histories.
In an afterword, Jennifer Brown describes her approach to Native history and offers advice to researchers. Although some essays deal with specific aspects of Anishinaabe, Cree, Ojibwe, and Metis history, the insights about the interactions between scholars and First Nations communities, and the variety of evidence available for the study of Aboriginal history, will be the principal legacies of this intriguing and useful volume
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Economic
Gastrointestinal tract size, total-tract digestibility, and rumen microflora in different dairy cow genotypes
peer-reviewedThe superior milk production efficiency of Jersey (JE) and Jersey × Holstein-Friesian (JE × HF) cows compared with Holstein-Friesian (HF) has been widely published. The biological differences among dairy cow genotypes, which could contribute to the milk production efficiency differences, have not been as widely studied however. A series of component studies were conducted using cows sourced from a longer-term genotype comparison study (JE, JE × HF, and HF). The objectives were to (1) determine if differences exist among genotypes regarding gastrointestinal tract (GIT) weight, (2) assess and quantify whether the genotypes tested differ in their ability to digest perennial ryegrass, and (3) examine the relative abundance of specific rumen microbial populations potentially relating to feed digestibility. Over 3 yr, the GIT weight was obtained from 33 HF, 35 JE, and 27 JE × HF nonlactating cows postslaughter. During the dry period the cows were offered a perennial ryegrass silage diet at maintenance level. The unadjusted GIT weight was heavier for the HF than for JE and JE × HF. When expressed as a proportion of body weight (BW), JE and JE × HF had a heavier GIT weight than HF. In vivo digestibility was evaluated on 16 each of JE, JE × HF, and HF lactating dairy cows. Cows were individually stalled, allowing for the total collection of feces and were offered freshly cut grass twice daily. During this time, daily milk yield, BW, and dry matter intake (DMI) were greater for HF and JE × HF than for JE; milk fat and protein concentration ranked oppositely. Daily milk solids yield did not differ among the 3 genotypes. Intake capacity, expressed as DMI per BW, tended to be different among treatments, with JE having the greatest DMI per BW, HF the lowest, and JE × HF being intermediate. Production efficiency, expressed as milk solids per DMI, was higher for JE than HF and JE × HF. Digestive efficiency, expressed as digestibility of dry matter, organic matter, N, neutral detergent fiber, and acid detergent fiber, was higher for JE than HF. In grazing cows (n = 15 per genotype) samples of rumen fluid, collected using a transesophageal sampling device, were analyzed to determine the relative abundance of rumen microbial populations of cellulolytic bacteria, protozoa, and fungi. These are critically important for fermentation of feed into short-chain fatty acids. A decrease was observed in the relative abundance of Ruminococcus flavefaciens in the JE rumen compared with HF and JE × HF. We can deduce from this study that the JE genotype has greater digestibility and a different rumen microbial population than HF. Jersey and JE × HF cows had a proportionally greater GIT weight than HF. These differences are likely to contribute to the production efficiency differences among genotypes previously reported
Bend it like Beckham: Hours and wages across forty-eight countries in 1900
Based largely on the Fifteenth Annual Report of the U.S. Department of Labor, published in 1900, we have built a sample of wages and hours for roughly fifty countries in six continents that covers the period 1890-1900. The Report, which is drawn from official (national) publications, gives information on normal or usual hours and earnings per week at the establishment level. To our knowledge, this is the most extensive data set of its kind totaling about 15,000 observations. We combine the data set with other country-specific evidence to derive implications about labour supply. The data reveal a cross-country supply curve that was markedly backward-bending. In addition, for a given wage level, we find a positive relation between a country's per-capita income and work hours. We interpret the patterns by proposing a standard utility function in consumption and hours of work, where a minimal level of consumption is introduced as a constraint. We interpret that minimum more broadly than biological subsistence. Rather minimal consumption is assumed to increase with the average income of a country. We also explore the possible role of climate in affecting the consumption constraint. Given the size of the data set, although coverage is uneven, we are able to estimate labour supply curves within countries and regions, in addition to making overall comparisons of work hours across countries. Our preliminary work suggests that a consumption constraint played a key role in the negative relation between wages and hours of work within countries, and that across countries higher average incomes, which effectively raised the constraint, promoted greater work hours
A long-term optical - X-ray correlation in 4U 1957+11
[abridged] Three years of optical monitoring of the low-mass X-ray binary
(LMXB) 4U 1957+11 is presented. The source was observed in V, R and i-bands
using the Faulkes Telescopes North and South. The light curve is dominated by
long-term variations which are correlated (at the > 3 sigma level) with the
RXTE ASM soft X-ray flux. The variations span one magnitude in all three
filters. We find no evidence for periodicities in our light curves, contrary to
a previous short-timescale optical study in which the flux varied on a 9.3-hour
sinusoidal period by a smaller amplitude. The optical spectral energy
distribution is blue and typical of LMXBs in outburst, as is the power law
index of the correlation beta = 0.5, where F_{nu,OPT} propto F_X^beta. The
discrete cross-correlation function reveals a peak at an X-ray lag of 2 - 14
days, which could be the viscous timescale. However, adopting the least squares
method the strongest correlation is at a lag of 0 +/- 4 days, consistent with
X-ray reprocessing on the surface of the disc. We therefore constrain the
optical lag behind X-ray to be between -14 and +4 days. In addition, we use the
optical - X-ray luminosity diagram for LMXBs as a diagnostic tool to constrain
the nature of the compact object in 4U 1957+11, since black hole (BH) and
neutron star (NS) sources reside in different regions of this diagram. If the
system contains a BH (as is the currently favoured hypothesis), its distance
must exceed ~ 20 kpc for the optical and X-ray luminosities to be consistent
with other soft state BH systems. For distances < 20 kpc, the data lie in a
region of the diagram populated only by NS sources. 4U 1957+11 is unique: it is
either the only BH LMXB to exist in an apparent persistent soft state, or it is
a NS LMXB which behaves like a black hole.Comment: MNRAS accepted, 12 pages, 8 figure
Pediatric trainees\u27 engagement in the online nutrition curriculum: preliminary results
Background: The Pediatric Nutrition Series (PNS) consists of ten online, interactive modules and supplementary educational materials that have utilized web-based multimedia technologies to offer nutrition education for pediatric trainees and practicing physicians. The purpose of the study was to evaluate pediatric trainees\u27 engagement, knowledge acquisition, and satisfaction with nutrition modules delivered online in interactive and non-interactive formats. Methods: From December 2010 through August 2011, pediatric trainees from seventy-three (73) different U. S. programs completed online nutrition modules designed to develop residents\u27 knowledge of counseling around and management of nutritional issues in children. Data were analyzed using SPSS version 19. Both descriptive and inferential statistics were used in comparing interactive versus non-interactive modules. Pretest/posttest and module evaluations measured knowledge acquisition and satisfaction. Results: Three hundred and twenty-two (322) pediatric trainees completed one or more of six modules for a total of four hundred and forty-two (442) accessions. All trainees who completed at least one module were included in the study. Two-way analyses of variance (ANOVA) with repeated measures (pre/posttest by interactive/non-interactive format) indicated significant knowledge gains from pretest to posttest (p \u3c 0.002 for all six modules). Comparisons between interactive and non-interactive formats for Module 1 (N = 85 interactive, N = 95 non-interactive) and Module 5 (N = 5 interactive, N = 16 non-interactive) indicated a parallel improvement from the pretest to posttest, with the interactive format significantly higher than the non-interactive modules (p \u3c .05). Both qualitative and quantitative data from module evaluations demonstrated that satisfaction with modules was high. However, there were lower ratings for whether learning objectives were met with Module 6 (p \u3c 0.03) and lecturer rating (p \u3c 0.004) compared to Module 1. Qualitative data also showed that completion of the interactive modules resulted in higher resident satisfaction. Conclusions: This initial assessment of the PNS modules shows that technology-mediated delivery of a nutrition curriculum in residency programs has great potential for providing rich learning environments for trainees while maintaining a high level of participant satisfaction
The substitution of a tetrahedron for the Einthoven triangle
In an experiment on a cadaver, a potential difference was rhythmically impressed upon two small electrodes thrust into the heart or its immediate neighborhood.The resulting differences in potential between a central terminal and four electrodes connected to it through equal resistances were recorded with the string galvanometer. The four electrodes were on the two arms, the left leg, and the left interscapular region.By assuming that the electrical field generated in the trunk was equivalent to that of a centric doublet in a homogeneous spherical conductor and that the four electrodes were at the apices of a tetrahedron inscribed in this sphere, the experimental and the theoretical amplitudes of the deflections in the four leads could be compared. In general, it may be said that, with one exception, the deflections in the limb leads had the relative magnitudes expected. The deflections in the lead from the back were much smaller than anticipated. The last result is attributed to circumstances peculiar to the single experiment performed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32563/1/0000689.pd
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