Electroweak Baryogenesis from Late Neutrino Masses

Electroweak Baryogenesis, given a first order phase transition, does not work in the standard model because the quark Yukawa matrices are too hierarchical. On the other hand, the neutrino mass matrix is apparently not hierarchical. In models with neutrino mass generation at low scales, the neutrino Yukawa couplings lead to large CP-violation in the reflection probability of heavy leptons by the expanding Higgs bubble wall, and can generate the observed baryon asymmetry of the universe. The mechanism predicts new vector-like leptons below the TeV scale and sizable mu -> e processes.Comment: 5 pages, 2 figures, references adde

Advancing tendencies? PR leadership, general leadership, and leadership pedagogy

What are the best ways to advance PR leadership? In exploring answers, we consider the last two decades of PR literature and identify two main tendencies. We link those two with general leadership literature and practices, as well as with literature on leadership pedagogy. We conclude that, rather than recent moves to look within the field, without self-reflection, to existing PR perspectives and figures for solutions, looking outwards has greater potential to transform not only the PR leadership literature, and PR practice, but also to create less hierarchical, and more democratic and "leaderful," PR workplaces. © 2014

ILR Impact Brief - Building Trust and Cooperation in Boundary-Spanning Teams

[Excerpt] Knowledge workers engaged in interorganizational collaborative initiatives (i.e., boundary spanners) can actively build and maintain interpersonal trust through a multi-step “threat regulation” process. Designed to mitigate counterparts’ fears that harm will arise out of the cooperative effort, threat regulation involves 1) perspective-taking (understanding how others might perceive and experience the risks of cooperation); 2) threat-reducing behavior (intentional efforts to influence others’ negative emotions); and 3) reflection (self-assessment leading to self-corrective actions). When hierarchical authority is absent, which is common in collaborative projects, boundary-spanners can adopt these behaviors to influence others’ emotions so as to gain the requisite trust and cooperation

Can Reflection from Grains Diagnose the Albedo?

By radiation transfer models with a realistic power spectra of the projected density distributions, we show that the optical properties of grains are poorly constrained by observations of reflection nebulae. The ISM is known to be hierarchically clumped from a variety of observations (molecules, H I, far-infrared). Our models assume the albedo and phase parameter of the dust, the radial optical depth of the sphere averaged over all directions, and random distributions of the dust within the sphere. The outputs are the stellar extinction, optical depth, and flux of scattered light as seen from various viewing angles. Observations provide the extinction and scattered flux from a particular direction. Hierarchical geometry has a large effect on the flux of scattered light emerging from a nebula for a particular extinction of the exciting star. There is a very large spread in both scattered fluxes and extinctions for any distribution of dust. Consequently, an observed stellar extinction and scattered flux can be fitted by a wide range of albedos. With hierarchical geometry it is not completely safe to determine even relative optical constants from multiwavelength observations of the same reflection nebula. The geometry effectively changes with wavelength as the opacity of the clumps varies. Limits on the implications of observing the same object in various wavelengths are discussed briefly. Henry (2002) uses a recipe to determine the scattered flux from a star with a given extinction. It is claimed to be independent of the geometry. It provides considerably more scattering than our models, probably leading to an underestimate of the grain albedos from the UV Diffuse Galactic Light.Comment: 27 pages, including 7 figures. Accepted by Ap

Sense of Place in the Anthropocene: A students-teaching-students course

Contemporary environmental education is tasked with the acknowledgement of the Anthropocene - an informal but ubiquitous term for the current geological epoch which arose from anthropogenic changes to the Earth system - and its accompanying socio-ecological implications. Sense of Place can be a hybridized tool of personal agency and global awareness for this task. Through the creation, execution and reflection of a 14-student students-teaching-students (STS) course at the University of Vermont in the Spring of 2019, Giannina Gaspero-Beckstrom and Ella Mighell aimed to facilitate a peer-to-peer learning environment that addressed sense of place, social justice and community engagement. The students-teaching-students framework is an alternative educational approach that supports the values and practices of the University of Vermont’s Environmental Program, as well as an intentional breakdown of the hierarchical knowledge paradigm. Using alternative pedagogies (predominately critical and place-based), we attempted to facilitate meaningful learning through creative expression, experiential education, community dialogue and personal reflection. Our intention with this was to encourage awareness and action

Cues and knowledge structures used by mental-health professionals when making risk assessments

Background: Research into mental-health risks has tended to focus on epidemiological approaches and to consider pieces of evidence in isolation. Less is known about the particular factors and their patterns of occurrence that influence clinicians’ risk judgements in practice. Aims: To identify the cues used by clinicians to make risk judgements and to explore how these combine within clinicians’ psychological representations of suicide, self-harm, self-neglect, and harm to others. Method: Content analysis was applied to semi-structured interviews conducted with 46 practitioners from various mental-health disciplines, using mind maps to represent the hierarchical relationships of data and concepts. Results: Strong consensus between experts meant their knowledge could be integrated into a single hierarchical structure for each risk. This revealed contrasting emphases between data and concepts underpinning risks, including: reflection and forethought for suicide; motivation for self-harm; situation and context for harm to others; and current presentation for self-neglect. Conclusions: Analysis of experts’ risk-assessment knowledge identified influential cues and their relationships to risks. It can inform development of valid risk-screening decision support systems that combine actuarial evidence with clinical expertise

Multi-scale strain-stiffening of semiflexible bundle networks

Bundles of polymer filaments are responsible for the rich and unique mechanical behaviors of many biomaterials, including cells and extracellular matrices. In fibrin biopolymers, whose nonlinear elastic properties are crucial for normal blood clotting, protofibrils self-assemble and bundle to form networks of semiflexible fibers. Here we show that the extraordinary strain-stiffening response of fibrin networks is a direct reflection of the hierarchical architecture of the fibrin fibers. We measure the rheology of networks of unbundled protofibrils and find excellent agreement with an affine model of extensible wormlike polymers. By direct comparison with these data, we show that physiological fibrin networks composed of thick fibers can be modeled as networks of tight protofibril bundles. We demonstrate that the tightness of coupling between protofibrils in the fibers can be tuned by the degree of enzymatic intermolecular crosslinking by the coagulation Factor XIII. Furthermore, at high stress, the protofibrils contribute independently to the network elasticity, which may reflect a decoupling of the tight bundle structure. The hierarchical architecture of fibrin fibers can thus account for the nonlinearity and enormous elastic resilience characteristic of blood clots.Comment: 27 pages including 8 figures and Supplementary Dat

2D shape classification and retrieval

We present a novel correspondence-based technique for efficient shape classification and retrieval. Shape boundaries are described by a set of (ad hoc) equally spaced points – avoiding the need to extract “landmark points”. By formulating the correspondence problem in terms of a simple generative model, we are able to efficiently compute matches that incorporate scale, translation, rotation and reflection invariance. A hierarchical scheme with likelihood cut-off provides additional speed-up. In contrast to many shape descriptors, the concept of a mean (prototype) shape follows naturally in this setting. This enables model based classification, greatly reducing the cost of the testing phase. Equal spacing of points can be defined in terms of either perimeter distance or radial angle. It is shown that combining the two leads to improved classification/retrieval performance.