The Geology and Geochemistry of the Agamenticus Complex, York, Maine

Guidebook for field trips in southern and west-central Maine, October 13, 14 and 15, 1989: New England Intercollegiate Geological Conference 81st annual meeting: Trip A-1; C-

Hydraulic characteristics of porous media

CER62RHB59.October 1962.Non-funded contributing project of the Western Regional Research Committee, Project W-51, Drainage Design for Irrigation Agriculture

Hydraulic properties of porous media

March 1964.Includes bibliographical references (page 20)

Properties of unsaturated porous media

November 1966.Includes bibliographical references (page 32)

Self-interest And Public Interest: The Motivations Of Political Actors

Self-Interest and Public Interest in Western Politics showed that the public, politicians, and bureaucrats are often public spirited. But this does not invalidate public-choice theory. Public-choice theory is an ideal type, not a claim that self-interest explains all political behavior. Instead, public-choice theory is useful in creating rules and institutions that guard against the worst case, which would be universal self-interestedness in politics. In contrast, the public-interest hypothesis is neither a comprehensive explanation of political behavior nor a sound basis for institutional design

Magnetically Driven Ferroelectric Order in Ni\u3csub\u3e3\u3c/sub\u3eV\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e8\u3c/sub\u3e

We show that long-range ferroelectric and incommensurate magnetic order appear simultaneously in a single phase transition in Ni3V2O8. The temperature and magnetic-field dependence of the spontaneous polarization show a strong coupling between magnetic and ferroelectric orders. We determine the magnetic symmetry using Landau theory for continuous phase transitions, which shows that the spin structure alone can break spatial inversion symmetry leading to ferroelectric order. This phenomenological theory explains our experimental observation that the spontaneous polarization is restricted to lie along the crystal b axis and predicts that the magnitude should be proportional to a magnetic order parameter

Field Dependence of Magnetic Ordering in Kagomé-Staircase Compound Ni\u3csub\u3e3\u3c/sub\u3eV\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e8\u3c/sub\u3e

We present powder and single-crystal neutron diffraction and bulk measurements of the Kagomé-staircase compound Ni3V2O8 (NVO) in fields up to 8.5T applied along the c direction. (The Kagomé plane is the a−c plane.) This system contains two types of Ni ions, which we call “spine” and “cross-tie.” Our neutron measurements can be described with the paramagnetic space group Cmca for T\u3c15K and each observed magnetically ordered phase is characterized by the appropriate irreducible representation(s). Our zero-field measurements show that at TPH=9.1K NVO undergoes a transition to a predominantly longitudinal incommensurate structure in which the spine spins are nearly along the a-axis. At THL=6.3K, there is a transition to an elliptically polarized incommensurate structure with both spine and cross-tie moments in the a−b plane. At TLC=4K the system undergoes a first-order phase transition to a commensurate antiferromagnetic structure with the staggered magnetization primarily along the a-axis and a weak ferromagnetic moment along the c-axis. A specific heat anomaly at TCC′=2.3K indicates an additional transition, which remarkably does not affect Bragg peaks of the commensurate C structure. Neutron, specific heat, and magnetization measurements produce a comprehensive temperature-field phase diagram. The symmetries of the incommensurate magnetic phases are consistent with the observation that only one phase is electrically polarized. The magnetic structures are explained theoretically using a simplified model Hamiltonian, that involves competing nearest- and next-nearest-neighbor exchange interactions, single-ion anisotropy, pseudodipolar interactions, and Dzyaloshinskii-Moriya interactions

Complex Magnetic Order in the Kagomé Staircase Compound Co\u3csub\u3e3\u3c/sub\u3eV\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e8\u3c/sub\u3e

Co3V2O8 (CVO) has a different type of geometrically frustrated magnetic lattice, a kagomé staircase, where the full frustration of a conventional kagomé lattice is partially relieved. The crystal structure consists of two inequivalent (magnetic) Co sites, one-dimensional chains of Co(2) spine sites, linked by Co(1) cross-tie sites. Neutron powder diffraction has been used to solve the basic magnetic and crystal structures of this system, while polarized and unpolarized single crystal diffraction measurements have been used to reveal a rich variety of incommensurate phases, interspersed with lock-in transitions to commensurate phases. CVO initially orders magnetically at 11.3K into an incommensurate, transversely polarized, spin density wave state, with wave vector k=(0,δ,0) with δ=0.55 and the spin direction along the a axis. δ is found to decrease monotonically with decreasing temperature and then locks into a commensurate antiferromagnetic structure with δ=1/2 for 6.9\u3cT\u3c8.6K. In this phase, there is a ferromagnetic layer where the spine site and cross-tie sites have ordered moments of 1.39μB and 1.17μB, respectively, and an antiferromagnetic layer where the spine-site has an ordered moment of 2.55μB, while the cross-tie sites are fully frustrated and have no observable ordered moment. Below 6.9K, the magnetic structure becomes incommensurate again, and the presence of higher-order satellite peaks indicates that the magnetic structure deviates from a simple sinusoid. δ continues to decrease with decreasing temperature and locks in again at δ=1/3 over a narrow temperature range (6.2\u3cT\u3c6.5K). The system then undergoes a strongly first-order transition to the ferromagnetic ground state (δ=0) at Tc=6.2K. The ferromagnetism partially relieves the cross-tie site frustration, with ordered moments on the spine-site and cross-tie sites of 2.73μB and 1.54μB, respectively. The spin direction for all spins is along the a axis (Ising-like behavior). A dielectric anomaly is observed around the ferromagnetic transition temperature of 6.2K, demonstrating that there is significant spin-charge coupling present in CVO. A theory based on group theory analysis and a minimal Ising model with competing exchange interactions can explain the basic features of the magnetic ordering

Longitudinal changes of brain microstructure and function in nonconcussed female rugby players

ObjectiveTo longitudinally assess brain microstructure and function in female varsity athletes participating in contact and noncontact sports.MethodsConcussion-free female rugby players (n = 73) were compared to age-matched (ages 18-23) female swimmers and rowers (n = 31) during the in- and off-season. Diffusion and resting-state fMRI (rs-fMRI) measures were the primary outcomes. The Sports Concussion Assessment Tool and head impact accelerometers were used to monitor symptoms and impacts, respectively.ResultsWe found cross-sectional (contact vs noncontact) and longitudinal (in- vs off-season) changes in white matter diffusion measures and rs-fMRI network connectivity in concussion-free contact athletes relative to noncontact athletes. In particular, mean, axial, and radial diffusivities were increased with decreased fractional anisotropy in multiple white matter tracts of contact athletes accompanied with default mode and visual network hyperconnectivity (p \u3c 0.001). Longitudinal diffusion changes in the brainstem between the in- and off-season were observed for concussion-free contact athletes only, with progressive changes observed in a subset of athletes over multiple seasons. Axial diffusivity was significantly lower in the genu and splenium of the corpus callosum in those contact athletes with a history of concussion.ConclusionsTogether, these findings demonstrate longitudinal changes in the microstructure and function of the brain in otherwise healthy, asymptomatic athletes participating in contact sport. Further research to understand the long-term brain health and biological implications of these changes is required, in particular to what extent these changes reflect compensatory, reparative, or degenerative processes

The emerging structure of the Extended Evolutionary Synthesis: where does Evo-Devo fit in?

The Extended Evolutionary Synthesis (EES) debate is gaining ground in contemporary evolutionary biology. In parallel, a number of philosophical standpoints have emerged in an attempt to clarify what exactly is represented by the EES. For Massimo Pigliucci, we are in the wake of the newest instantiation of a persisting Kuhnian paradigm; in contrast, Telmo Pievani has contended that the transition to an EES could be best represented as a progressive reformation of a prior Lakatosian scientific research program, with the extension of its Neo-Darwinian core and the addition of a brand-new protective belt of assumptions and auxiliary hypotheses. Here, we argue that those philosophical vantage points are not the only ways to interpret what current proposals to ‘extend’ the Modern Synthesis-derived ‘standard evolutionary theory’ (SET) entail in terms of theoretical change in evolutionary biology. We specifically propose the image of the emergent EES as a vast network of models and interweaved representations that, instantiated in diverse practices, are connected and related in multiple ways. Under that assumption, the EES could be articulated around a paraconsistent network of evolutionary theories (including some elements of the SET), as well as models, practices and representation systems of contemporary evolutionary biology, with edges and nodes that change their position and centrality as a consequence of the co-construction and stabilization of facts and historical discussions revolving around the epistemic goals of this area of the life sciences. We then critically examine the purported structure of the EES—published by Laland and collaborators in 2015—in light of our own network-based proposal. Finally, we consider which epistemic units of Evo-Devo are present or still missing from the EES, in preparation for further analyses of the topic of explanatory integration in this conceptual framework