Variability of Millennial-Scale Trends in the Geomagnetic Axial Dipole

The historical trend in the axial dipole is sufficient to reverse the field in less than 2 kyr. Assessing the prospect of an imminent polarity reversal depends on the probability of sustaining the historical trend for long enough to produce a reversal. We use a stochastic model to predict the variability of trends for arbitrary time windows. Our predictions agree well with the trends computed from paleomagnetic models. Applying these predictions to the historical record shows that the current trend is likely due to natural variability. Furthermore, an extrapolation of the current trend for the next 1 to 2 kyr is highly unlikely. Instead, we compute the trend and time window needed to reverse the field with a specified probability. We find that the dipole could reverse in the next 20 kyr with a probability of 2%

Visco-magnetic torque at the core mantle boundary

A magneto-hydrodynamic model of boundary layers at the Core-Mantle Boundary (CMB) is derived and used to compute the viscous and electromagnetic torques generated by the Earth's nutation forcing. The predicted electromagnetic torque alone cannot account for the dissipation estimated from the observations of the free core nutation. The presence of a viscous boundary layer in the electromagnetic skin layer at the CMB, with its additional dissipative torques, may explain the geodetic data. An apparent Ekman number at the top of the core between 3 and $5 10^{-11}$ is inferred depending on the electrical conductivity of the mantle

From Clouds to Streams: A Process-Oriented Exploration of Indigenous Research

Indigenous research seeks to bring worldview and relationality1 to the forefront of our work. While metaphor and imagery are widely encouraged within Indigenous storytelling,2 the concept is relatively novel within academic circles. This process-oriented presentation draws on a powerful metaphor describing the untold phases of Indigenous research: time spent looking to the clouds, dancing for rain, and wading into streams. In this offering, we will explore the natural cycle of water and its kinship to an Indigenized research process. Symbolically, water is a central force in Indigenous worldviews and an essential element of life. This symbol translates seamlessly to describe aspects involved in our research processes, including the collective mind and sacred knowledge, the role of water in sharing, cleansing, healing, and sustaining, and its place in renewal, nourishment, growth, and integration. This exploration provides a strong rationale for the inherent value of attending carefully to the research process as equal to its outcomes. This presentation will also re-assert the crucial inclusion of metaphor and storytelling in Indigenized academic research and their immense potential for knowledge transmission within the academy and the community.  “From Clouds to Streams: A Process-Oriented Exploration of Indigenous Research” lends itself fluidly to each of the proposed symposium themes of Centering Indigenous Paradigms, Knowledges, and Research Practices; Renewing & Reimagining Knowledge Transmission: Past, Present, Future; Nurturing the Relationship between Community and Research; and Embodying & Actioning Interventions through Indigenous Research. 1  Shawn Wilson. Research Is Ceremony: Indigenous Research Methods. (Blackpoint: Fernwood Publishing, 2008), 84-96. 2  Jo-ann et Archibald et al., eds. Decolonizing Research: Indigenous Storywork as Methodology. (London: Zed Books Ltd., 2019), 1-13.

Changes in the Tibial Epiphyseal Cartilage of the Rat Following Adrenalectomy and Gonadectomy

Thesis (Ph.D.)--Boston UniversityThe present investigation was undertaken to study the effects of adrenalectomy, gonadectomy, and adreno-gonadectomy on the region of the proximal tibial epiphyseal cartilage plate in male and female rats. Although considerable attention has been directed in recent years to the effects of hypophysectomy, thyroidectomy, and the administration of growth, thyroid, adrenocortical, and sex hormones on cartilage growth, there has been little emphasis on the effects of adrenalectomy or gonadectomy. Littermate rats of the Long-Evans strain were segregated into five groups which were to be sacrificed at 80 to 99, 100 to 124, 125 to 149, 150 to 174, and 175 to 200 days of age, respectively. Each group was in turn subdivided into control, adrenalectomized, gonadectomized, and adreno-gonadectomized groups. All animals were maintained on Purina laboratory chow and water ad libitum, the adrenalectomized animals being given one per cent saline drinking water. The experimental animals were sacrificed three weeks postoperatively. At autopsy, both tibiae were removed from each animal, and one was split sagittally, stained with silver nitra.te, and the width of its uncalcified epiphyseal cartilage measured immediately with a calibrated ocular micrometer. Mean cartilage widths (and standard deviations) were calculated for the similarly treated animals of each sex in each of the five age groups, and the accumulated data analyzed statistically by means of the Student-Fisher t-test and the Cochran and Cox test. The uncalcified cartilage in adrenalectomized males and females, gonadectomized females, and adreno-gonadectomized males and females,in all age groups, showed a statistically significant increase in width over that of littermate controls. The increase in width became progressively greater with increasing age, and was slightly greater in adrenalectomized females than in adrenalectomized males. It was of approximately the same magnitude in gonadectomized females as in adrenalectomized females; in adreno-gonadectomized males it approximated that in adrenalectomized males; and it was somewhat greater in adreno-gonadectomized females than in either adrenalectomized or gonadectomized females. The uncalcified cartilage of gonadectomized males showed a statistically significant increase in width in only one age group (100 to 124 days), where it approximated that in adrenalectomized males. [TRUNCATED

How Our Public Education System Discourages Curiosity and Encourages Depression and Anxiety

The increase in adolescent depression over the last decade has been well- documented. Though promising treatments continue to be developed, the rate of increase is clearly outpacing our ability to help those who suffer. As such, it is worth taking a look at what factors may be contributing to this increase. The argument contained in this paper is that the nature of public education, in particular its existential reliance on extrinsic motivation, encourages depression through both implicit and explicit discouragement of curiosity. Curiosity will be posited as key marker of human vitality, and human vitality will be investigated as an inherently prosocial phenomenon. Self-Determination Theory’s proposition of basic psychological needs will provide an understanding of how this prosocial nature can be nurtured, as well as a lens through which to understand the fundamentally incompatible relationship between the current state of public education and curiosity. The paper will conclude with some thoughts on the puzzle of meaningful school reform

Constructing Stochastic Models for Dipole Fluctuations from Paleomagnetic Observations

Records of relative paleointensity are subject to several sources of error. Temporal averaging due to gradual acquisition of magnetization removes high-frequency fluctuations, whereas random errors introduce fluctuations at high frequency. Both sources of error limit our ability to construct stochastic models from paleomagnetic observations. We partially circumvent these difficulties by recognizing that the largest affects occur at high frequency. To illustrate we construct a stochastic model from two recent inversions of paleomagnetic observations for the axial dipole moment. An estimate of the noise term in the stochastic model is recovered from a high-resolution inversion (CALS10k.2), while the drift term is estimated from the low-frequency part of the power spectrum for a long, but lower-resolution inversion (PADM2M). Realizations of the resulting stochastic model yield a composite, broadband power spectrum that agrees well with the spectra from both PADM2M and CALS10k.2. A simple generalization of the stochastic model permits predictions for the mean rate of magnetic reversals. We show that the reversal rate depends on the time-averaged dipole moment, the variance of the dipole moment and a slow timescale that characterizes the adjustment of the dipole toward the time-averaged value. Predictions of the stochastic model give a mean rate of 4.2 Myr^(−1), which is in good agreement with observations from marine magnetic anomalies

The relation of internal secretions to the growth of bone

Thesis (M.A.)--Boston University, 1948. This item was digitized by the Internet Archive

Buffett Early Childhood Institute: Five year report 2013-18

The Buffett Early Childhood Institute began operations in June 2013. We were charged with creating a new model for how public higher education can engage in early education by helping to transform the lives of young children and their families. This report presents a by-thenumbers profile of who we are and what we’ve accomplished in our first five years. Following the numbers you’ll find brief descriptions of programs, initiatives, financials, and the Institute itself