Bull Threshers and Bindlestiffs: Harvesting and Threshing on the North American Plains

Bull Threshers and Bindlestiffs is a panorama on a continental canvas: the Great Plains of North America, stretching from Texas to Alberta. Onto this surface the author lays the large features of regional practice in the harvesting and threshing of wheat during the days before the combined harvester harvesting with binder and header, threshing with bull thresher and steam engine. Into the picture he places the key figures who accomplished the task of gathering the grain the farm men and women, the custom threshermen, and the bindlestiffs, or itinerant laborers. Affectionately he sketches the small details of folklife that comprised the everyday work and culture of the wheat belt building shocks, loading racks, constructing stacks, pitching bundles into the separator, hauling water to the engine, drinking deep from the crockery water jug. Bull Threshers and Bindlestiffs is a profusely illustrated study of a complex, vigorous regional culture concerned with the production of wheat a culture that centered around the annual harvest and declined with the advent of the combine. This is an examination of the interaction of culture, environment, and technology with import for the fields of agricultural history and regional history. More than that, with its grassroots research, its descriptions of tools and customs, and its lavish illustrations, it is a re-creation of a proud phase of regional life previously captured only in yellowed albumen photographs. Description Thomas D. Isern is Professor of History & University Distinguished Professor of History at North Dakota State University. He is the author and coauthor of six books, including Dakota Circle: Excursions on the True Plains and Custom Combining on the Great Plains. This Kansas Open Books title is funded by a grant from the National Endowment for the Humanities and the Andrew W. Mellon Foundation Humanities Open Book Program.https://digitalcommons.pittstate.edu/kansas_open_books/1033/thumbnail.jp

Bull Threshers and Bindlestiffs: Harvesting and Threshing on the North American Plains

Thomas D. Isern is Professor of History & University Distinguished Professor of History at North Dakota State University. He is the author and coauthor of six books, including Dakota Circle: Excursions on the True Plains and Custom Combining on the Great Plains.This Kansas Open Books title is funded by a grant from the National Endowment for the Humanities and the Andrew W. Mellon Foundation Humanities Open Book Program.Bull Threshers and Bindlestiffs is a panorama on a continental canvas: the Great Plains of North America, stretching from Texas to Alberta. Onto this surface the author lays the large features of regional practice in the harvesting and threshing of wheat during the days before the combined harvester harvesting with binder and header, threshing with bull thresher and steam engine. Into the picture he places the key figures who accomplished the task of gathering the grain the farm men and women, the custom threshermen, and the bindlestiffs, or itinerant laborers. Affectionately he sketches the small details of folklife that comprised the everyday work and culture of the wheat belt building shocks, loading racks, constructing stacks, pitching bundles into the separator, hauling water to the engine, drinking deep from the crockery water jug. Bull Threshers and Bindlestiffs is a profusely illustrated study of a complex, vigorous regional culture concerned with the production of wheat a culture that centered around the annual harvest and declined with the advent of the combine. This is an examination of the interaction of culture, environment, and technology with import for the fields of agricultural history and regional history. More than that, with its grassroots research, its descriptions of tools and customs, and its lavish illustrations, it is a re-creation of a proud phase of regional life previously captured only in yellowed albumen photographs

Gravitational settling of 22Ne and white dwarf evolution

We study the effects of the sedimentation of the trace element 22Ne in the cooling of white dwarfs. In contrast with previous studies, which adopted a simplified treatment of the effects of 22Ne sedimentation, this is done self-consistently for the first time, using an up-to-date stellar evolutionary code in which the diffusion equation is coupled with the full set of equations of stellar evolution. Due the large neutron excess of 22Ne, this isotope rapidly sediments in the interior of the white dwarf. Although we explore a wide range of parameters, we find that using the most reasonable assumptions concerning the diffusion coefficient and the physical state of the white dwarf interior the delay introduced by the ensuing chemical differentation is minor for a typical 0.6 Msun white dwarf. For more massive white dwarfs, say M_Wd about 1.0 Msun, the delay turns out to be considerably larger. These results are in qualitatively good accord with those obtained in previous studies, but we find that the magnitude of the delay introduced by 22Ne sedimentation was underestimated by a factor of about 2. We also perform a preliminary study of the impact of 22Ne sedimentation on the white dwarf luminosity function. Finally, we hypothesize as well on the possibility of detecting the sedimentation of 22Ne using pulsating white dwarfs in the appropriate effective temperature range with accurately determined rates of change of the observed periods.Comment: To apper in The Astrophysical Journa

Evolution of white dwarf stars with high-metallicity progenitors: the role of 22Ne diffusion

Motivated by the strong discrepancy between the main sequence turn-off age and the white dwarf cooling age in the metal-rich open cluster NGC 6791, we compute a grid of white dwarf evolutionary sequences that incorporates for the first time the energy released by the processes of 22Ne sedimentation and of carbon/oxygen phase separation upon crystallization. The grid covers the mass range from 0.52 to 1.0 Msun, and it is appropriate for the study of white dwarfs in metal-rich clusters. The evolutionary calculations are based on a detailed and self-consistent treatment of the energy released from these two processes, as well as on the employment of realistic carbon/oxygen profiles, of relevance for an accurate evaluation of the energy released by carbon/oxygen phase separation. We find that 22Ne sedimentation strongly delays the cooling rate of white dwarfs stemming from progenitors with high metallicities at moderate luminosities, whilst carbon/oxygen phase separation adds considerable delays at low luminosities. Cooling times are sensitive to possible uncertainties in the actual value of the diffusion coefficient of 22Ne. Changing the diffusion coefficient by a factor of 2, leads to maximum age differences of approx. 8-20% depending on the stellar mass. We find that the magnitude of the delays resulting from chemical changes in the core is consistent with the slow down in the white dwarf cooling rate that is required to solve the age discrepancy in NGC 6791.Comment: 10 pages, 6 figures, to be published in The Astrophysical Journa

The rate of cooling of the pulsating white dwarf star G117−-B15A: a new asteroseismological inference of the axion mass

We employ a state-of-the-art asteroseismological model of G117-B15A, the archetype of the H-rich atmosphere (DA) white dwarf pulsators (also known as DAV or ZZ Ceti variables), and use the most recently measured value of the rate of period change for the dominant mode of this pulsating star to derive a new constraint on the mass of axion, the still conjectural non-barionic particle considered as candidate for dark matter of the Universe. Assuming that G117-B15A is truly represented by our asteroseismological model, and in particular, that the period of the dominant mode is associated to a pulsation g-mode trapped in the H envelope, we find strong indications of the existence of extra cooling in this star, compatible with emission of axions of mass m_a \cos^2 \beta = 17.4^{+2.3}_{-2.7} meV.Comment: 9 pages, 5 figures and 3 tables. Accepted for publication in MNRA

White dwarf constraints on a varying GG

A secular variation of $G$ modifies the structure and evolutionary time scales of white dwarfs. Using an state-of-the-art stellar evolutionary code, an up-to-date pulsational code, and a detailed population synthesis code we demonstrate that the effects of a running $G$ are obvious both in the properties of individual white dwarfs, and in those of the white dwarf populations in clusters. Specifically, we show that the white dwarf evolutionary sequences depend on both the value of $\dot G/G$, and on the value of $G$ when the white dwarf was born. We show as well that the pulsational properties of variable white dwarfs can be used to constrain $\dot G/G$. Finally, we also show that the ensemble properties of of white dwarfs in clusters can also be used to set upper bounds to $\dot G/G$. Precisely, the tightest bound --- $\dot G/G \sim -1.8 10^{-12}$ yr$^{-1}$ --- is obtained studying the population of the old, metal-rich, well populated, open cluster NGC 6791. Less stringent upper limits can be obtained comparing the theoretical results obtained taking into account the effects of a running $G$ with the measured rates of change of the periods of two well studied pulsating white dwarfs, G117--B15A and R548. Using these white dwarfs we obtain $\dot G/G\sim -1.8\times 10^{-10}$ yr$^{-1}$, and $\dot G/G\sim -1.3\times 10^{-10}$ yr$^{-1}$, respectively, which although less restrictive than the previous bound, can be improved measuring the rate of change of the period of massive white dwarfs.Comment: 6 pages, 3 figures. To be published in the proceedings of the conference "Varying fundamental constants and dynamical dark energy" (8 - 13 July 2013, Sexten Center for Astrophysics

Gravitational Settling of ^{22}Ne in Liquid White Dwarf Interiors--Cooling and Seismological Effects

We assess the impact of the trace element ^{22}Ne on the cooling and seismology of a liquid C/O white dwarf (WD). Due to this elements' neutron excess, it sinks towards the interior as the liquid WD cools. The subsequent gravitational energy released slows the cooling of the WD by 0.25--1.6 Gyrs by the time it has completely crystallized, depending on the WD mass and the adopted sedimentation rate. The effects will make massive WDs or those in metal rich clusters (such as NGC 6791) appear younger than their true age. Our diffusion calculations show that the ^{22}Ne mass fraction in the crystallized core actually increases outwards. The stability of this configuration has not yet been determined. In the liquid state, the settled ^{22}Ne enhances the internal buoyancy of the interior and changes the periods of the high radial order g-modes by approximately 1%. Though a small adjustment, this level of change far exceeds the accuracy of the period measurements. A full assessment and comparison of mode frequencies for specific WDs should help constrain the still uncertain ^{22}Ne diffusion coefficient for the liquid interior.Comment: 26 pages (11 text pages with 15 figures); to appear in The Astrophysical Journa

The ages of very cool hydrogen-rich white dwarfs

The evolution of white dwarfs is essentially a cooling process that depends primarily on the energy stored in their degenerate cores and on the transparency of their envelopes. In this paper we compute accurate cooling sequences for carbon-oxygen white dwarfs with hydrogen dominated atmospheres for the full range of masses of interest. For this purpose we use the most accurate available physical inputs for both the equation of state and opacities of the envelope and for the thermodynamic quantities of the degenerate core. We also investigate the role of the latent heat in the computed cooling sequences. We present separately cooling sequences in which the effects of phase separation of the carbon-oxygen binary mixture upon crystallization have been neglected, and the delay introduced in the cooling times when this mechanism is properly taken into account, in order to compare our results with other published cooling sequences which do not include a treatment of this phenomenon. We find that the cooling ages of very cool white dwarfs with pure hydrogen atmospheres have been systematically underestimated by roughly 1.5 Gyr at log(L/Lo)=-4.5 for an otherwise typical 0.6 Mo white dwarf, when phase separation is neglected. If phase separation of the binary mixture is included then the cooling ages are further increased by roughly 10%. Cooling tracks and cooling isochrones in several color-magnitude diagrams are presented as well.Comment: 8 Pages; ApJ, accepted for publicatio

Experiences in the development of electronic care plans for the management of comorbidities

Recent studies have shown that care plans with comprehen- sive home interventions can be effective in the management of chronic patients. Evidence also exists about the importance of tailoring these care plans to patients, by integrating comorbidities. In this context, the de- velopment, implementation, outcome analysis, and reengineering of care plans adapted to particular patient groups earn relevance. We are con- cerned with the development and reengineering of electronic care plans dealing with comorbidities. Our hypothesis is that a library of reusable care plan components can facilitate these tasks. To confirm this hypoth- esis we have carried out an experiment consisting in developing a library of care plan components for the management of patients with COPD3 or CHF4, and next building a care plan for stable COPD&CHF patients by (re)using these components. In this paper we report on this experimen

The Possible White Dwarf-Neutron Star Connection

The current status of the problem of whether neutron stars can form, in close binary systems, by accretion-induced collapse (AIC) of white dwarfs is examined. We find that, in principle, both initially cold C+O white dwarfs in the high-mass tail of their mass distribution in binaries and O+Ne+Mg white dwarfs can produce neutron stars. Which fractions of neutron stars in different types of binaries (or descendants from binaries) might originate from this process remains uncertain.Comment: 6 pages. To appear in "White Dwarfs", ed. J. Isern, M. Hernanz, and E. Garcia-Berro (Dordrecht: Kluwer