The Birkhoff-Maltsev problem asks for a characterization of those lattices each of which is isomorphic to the lattice L(K) of all subquasivarieties for some quasivariety K of algebraic systems. The current status of this problem, which is still open, is discussed. Various unsolved questions that are related to the Birkhoff-Maltsev problem are also considered, including ones that stem from the theory of propositional logics.

LetL(K) denote the lattice (ordered by inclusion) of quasivarieties contained in a quasivarietyK and letD 2 denote the variety of distributive (0, 1)-lattices with 2 additional nullary operations. In the present paperL(D 2) is described. As a consequence, ifM+N stands for the lattice join of the quasivarietiesM andN, then minimal quasivarietiesV 0,V 1, andV 2 are given each of which is generated by a 2-element algebra and such that the latticeL(V 0+V1), though infinite, still admits an easy and nice description (...) (see Figure 2) while the latticeL(V 0+V1+V2), because of its intricate inner structure, does not. In particular, it is shown thatL(V 0+V1+V2) contains as a sublattice the ideal lattice of a free lattice with free generators. Each of the quasivarietiesV 0,V 1, andV 2 is generated by a 2-element algebra inD 2. (shrink)

© 2017. The American Astronomical Society. All rights reserved.We present new observations of the low-mass companion to HD 984 taken with the Gemini Planet Imager as a part of the GPI Exoplanet Survey campaign. Images of HD 984 B were obtained in the J and H bands. Combined with archival epochs from 2012 and 2014, we fit the first orbit to the companion to find an 18 au orbit with a 68% confidence interval between 14 and 28 au, an eccentricity (...) of 0.18 with a 68% confidence interval between 0.05 and 0.47, and an inclination of 119°with a 68% confidence interval between 114°and 125°. To address the considerable spectral covariance in both spectra, we present a method of splitting the spectra into low and high frequencies to analyze the spectral structure at different spatial frequencies with the proper spectral noise correlation. Using the split spectra, we compare them to known spectral types using field brown dwarf and low-mass star spectra and find a best-fit match of a field gravity M6.5 ±1.5 spectral type with a corresponding temperature of K. Photometry of the companion yields a luminosity of log=2.88 ± 0.07 dex with DUSTY models. Mass estimates, again from DUSTY models, find an age-dependent mass of 34 ±1 to 95 ±4 M Jup. These results are consistent with previous measurements of the object. (shrink)

The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into (...) two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop. (shrink)

Growing concern has been expressed that we have entered a “post-truth” era in which each of us willfully believes whatever we choose, aided and abetted by alternative and social media that spin alternative realities for boutique consumption. A prime example of the belief in alternative realities is said to be acceptance of “conspiracy theories”—a term that is often used as a pejorative to indict claims of conspiracy that are so obviously absurd that only the unhinged could believe them. The epistemological (...) standard often involved in this indictment, however—the standard of “obvious” falsity—invites subjectivity in its application, because what is obviously false to one person can be common sense to another. This is not just a truism; considerable research suggests that people’s political beliefs, in general, and their acceptance or rejection of conspiracy theories in particular, tends in large part to be determined by partisan, ideological, and other priors. (shrink)

Despite the interpersonal nature of family meetings and the frequency in which they occur, the clinical ethics literature is devoid of any rich descriptions of what clinical ethicists should actually be doing during family meetings. Here, we propose a framework for describing and understanding “transitioning” facilitation skills based on a retrospective review of our internal documentation of 100 consecutive cases wherein a clinical ethicist facilitated at least one family meeting. The internal documents were analyzed using qualitative methodologies, i.e., “codes”, to (...) identify emergent themes. We identified four different transitioning strategies clinical ethicists use to reach a meaningful resolution. These transitioning strategies serve as a jumping-off point for additional analyses, future research, evaluating clinical ethics consultation, and overall performance improvement of a consultation service. (shrink)

The past three years have seen a dramatic increase in our understanding of the structural organization and expression strategies of the dispersed, repetitive yeast transposon, Ty. These studies have led to a logical comparison of Ty with retroviral proviruses and other mobile, repetitive elements. Such comparisons have culminated in the hypotheses that transposition occurs via the formation of Ty‐encoded virus‐like particles and that these particles represent a basic unit of all ‘retro‐systems’.

While agreeing with Poteat that the modern Western culture has gone awry in a humanly destructive way, the paper contends tha the culprit was not, as Poteat claims, Enlightenment critical philosophy, but the materialistic values of the bourgeois form of life and the puritanical view of knowledge and the naturalistic worldview that they generated. Accordingly, the solution proposed is not Poteat's unreflected experience and commonsense worldview but a shift to a humanistic culture-generating stance and a critical humanistic philosophy.