Gravitational Waves in the Spectral Action of Noncommutative Geometry

The spectral triple approach to noncommutative geometry allows one to develop the entire standard model (and supersymmetric extensions) of particle physics from a purely geometry stand point and thus treats both gravity and particle physics on the same footing. The bosonic sector of the theory contains a modification to Einstein-Hilbert gravity, involving a nonconformal coupling of curvature to the Higgs field and conformal Weyl term (in addition to a nondynamical topological term). In this paper we derive the weak field limit of this gravitational theory and show that the production and dynamics of gravitational waves are significantly altered. In particular, we show that the graviton contains a massive mode that alters the energy lost to gravitational radiation, in systems with evolving quadrupole moment. We explicitly calculate the general solution and apply it to systems with periodically varying quadrupole moments, focusing in particular on the the well know energy loss formula for circular binaries.Comment: 15 pages, 3 figure

Engaging Diversity And Marginalization Through Participatory Action Research: A Model For Independent School Reform

Authored by a university researcher, school practitioner, and high school student, this article examines how independent schools can utilize participatory action research (PAR) to bolster diversity and inclusion efforts. A case study approach was taken to showcase a two-year PAR project at a progressive independent school that sought to: (a) enrich institutional knowledge of student diversity, (b) capture the present-day schooling experiences of historically marginalized students in independent school settings, and (c) develop a dynamic action plan to ameliorate school issues that emerged through the PAR inquiry process. Committed to institutional research that informs school policy and practice, we argue that PAR provides a rigorous, student-centered, and democratic model for independent school reform

Race, Class, And Gender In Boys\u27 Education: Repositioning Intersectionality Theory

Boys\u27 identities are distinctly gendered, racialized, and classed across disparate social and cultural contexts. Related intersectional identity processes are associated with boys\u27 academic success. While intersectionality has been utilized throughout boys\u27 education scholarship, a limited, light touch approach is often enacted. As a critical logic of interpretation, intersectionality theory accounts for race, class, and gender within equity-based empirical studies. The authors contend insufficient engagement with intersectionality may lead educational research on boys\u27 social and learner identities to become static. Examining boys\u27 identities through intersectional approaches reveals more complex insights particularly related to their school engagement. Critical of the recent boy crisis literature, this article strives to compel theorists of boys\u27 education to more fully leverage the history, constructs, and epistemologies of intersectionality

OR15-5 Human Sex Determination at the Edge of Ambiguity: Impaired SRY Phosphorylation Attenuates Expression of the Male Program

A paradox is posed by metazoan gene-regulatory networks (GRNs) that are robust yet evolvable. Insight may be obtained through studies of bistable genetic circuits mediating developmental decisions. A model in organogenesis is provided by the sex-specific differentiation of the embryonic gonadal ridge to form a testis or ovary. Here, we investigated a Swyer mutation in human testis-determining factor SRY that impairs its phosphorylation in association with variable developmental outcomes: fertile male, intersex, or infertile female (46, XY pure gonadal dysgenesis). The mutation (R30I) abrogates serine phosphorylation within a putative target site for protein kinase A (PKA) N-terminal to the HMG box. Diverse processes can be regulated by protein phosphorylation, including DNA recognition by transcription factors (TFs). Phosphorylation of this site in human SRY (LRRSSSFLCT; italics) in vitro was previously shown to enhance specific DNA affinity. Biological consequences of the mutation were evaluated in SRY-responsive mammalian cell lines following transient transfection. The mutation attenuated in concert occupancy of a target enhancer (TESCO) and SOX9 transcriptional activation. These perturbations were mitigated by acidic substitution (LRIDDDFL) whereas Ala substitutions (RRAAAFL or RIAAAFL) attenuated activity to an extent similar to R30I alone. No differences were observed in nuclear localization. Mutagenesis suggested that the central Ser is most efficiently phosphorylated in accord with PKA targeting rules. Replacement of the native site by an optimized “Kemptide” PKA site (LRRASLGCT) enhanced both SRY phosphorylation and SOX9 transcriptional activation whereas a “swapped” protein-kinase C determinant (LRRSSFRRCT) blocked phosphorylation. Among SRY variants, extent of cellular phosphorylation mirrored relative in vitro efficiencies of synthetic SRY-derived peptides as PKA-specific substrates. Although several kinases are predicted in silico to target this tri-serine motif, cell-based studies implicate PKA as the relevant kinase in vivo. Our results provide evidence that primate Sry requires its phosphorylation for full gene-regulatory activity. A PKA site N-terminal to the SRY HMG box, unique to primates, exemplifies network “tinkering” through recruitment of a new regulatory linkage. Molecular characterization of the R30I inherited Swyer mutation in SRY thus demonstrates that impaired TF phosphorylation can attenuate a human developmental switch at the edge of ambiguity

Endogenous Protection in General Equilibrium: estimating political weights in the EU

We examine the political economy underpinnings of import protection in general equilibrium. Starting from a dual theoretical representation of production, trade, and consumption, we map a general representation of the real economy to underlying political processes aka the political support function to derive a general representation of the determinants of import protection. This includes the relatively standard approach of examining the pattern of tariffs in a Grossman-Helpman framework, as well as recent extensions linked to upstream and downstream linkages between sectors. Because we start from a relatively generic general equilibrium model of production, we have an immediate bridge between the theory and general equilibrium-based estimates of the welfare effects and rents generated by tariffs. We therefore follow the development of our generalized theoretical framework by introducing the use of general equilibrium estimates of the direct and indirect marginal impacts of protection at the sector level for econometric estimation of the revealed pattern of policy weights. This GE approach yields direct estimates of political weights based on economic effects, including cross-industry effects. The resulting weights lend insight into relative protection of agriculture and manufacturing. Working with data on the European union, we find that the strength of downstream linkages matters for policy weights and rates of protection, as does the national posture of industry. We also find support for a general political support function in the determination of tariffs, though results are mixed for the more narrow Grossman-Helpman specification. In the EU, nationality of industry seems to play a role in the setting of Community-wide import protection.political weights, political economy of import protection, Grossman-Helpman model

A Model for Partial Viscous Sintering

A mathematical model describing the sintering rate of a viscous material powder bed is presented. This model assumes that the powder bed is composed of cubic packed, equal-size spherical particles. The sintering rate equation is derived in terms of a unit cell dimension or the relative density of a powder bed. A mathematical factor, fraction of sintering, is introduced to explain the phenomena of partial sintering. Key words: model, viscous sintering.Mechanical Engineerin