Interview with Scott and Carrie Logan by Mike Hastings

Biographical NoteScott Logan was born on February 17, 1977, in Exeter, New Hampshire. His father, Terence Logan, held a Ph.D. from Harvard University and taught English at the University of New Hampshire. Scott’s mother was from rural southern Maryland, and they met at Newton College of the Sacred Heart, in Newton, Massachusetts, where Terence was a professor and Scott’s mother was a student. Scott grew up in Kennebunk, Maine, and was interested in collecting and selling antiques, and in local history. For this business, he received a scholarship from the National Association of the Self-Employed. He was also one of the first Mitchell Scholars, in 1995, attending Bowdoin College and graduating in 1999. He first met his future wife, Carrie, at Bowdoin through their mutual membership in Alpha Delta Phi fraternity. He worked at Christie’s Auction Company and then the auctioneering firm Skinner, Inc. He then attended law school at Boston College, and at the time of this interview, he was an attorney specializing in consumer bankruptcy. Carrie Logan was born on December 24, 1977, in Portland, Maine, to Donald McGilvery and Cheryl Poulin McGilvery. Her parents, both from Maine, met at Cony High School, and both were graduated from the University of Maine, Orono. Her father worked in architecture and construction management for the Maine State Housing Authority, and her mother worked in education and at the time of this interview was the secretary at William H. Rowe School in Yarmouth. Carrie grew up in Yarmouth, Maine, attended Yarmouth public schools, and was selected as a Mitchell Scholar. She attended Bowdoin College, where she met Scott, and was graduated with the class of 2000. Through the Teach For America program, she taught in Opelousas, Louisiana, for two years and then became an English-as-a-Second-Language teacher in Houston, Texas, before returning to Maine to study at the University of Maine School of Law. She took her law degree in 2007 and was practicing business and real estate law at Preti Flaherty in Portland, Maine, at the time of this interview. SummaryInterview includes discussion of: Scott’s family and educational background in Kennebunk; Scott’s antique bottle interest; Scott’s education; Carrie’s family and educational background in Yarmouth; the decision to go to Bowdoin College; paying for college; the Mitchell Institute and Mitchell Scholarship; life at Bowdoin and Alpha Delta Phi; Carrie’s work teaching in the South with Teach for America; coming back to Maine; Scott dealing antiques; and more recent involvement with the Mitchell Institute

A model for rolling swarms of locusts

We construct an individual-based kinematic model of rolling migratory locust swarms. The model incorporates social interactions, gravity, wind, and the effect of the impenetrable boundary formed by the ground. We study the model using numerical simulations and tools from statistical mechanics, namely the notion of H-stability. For a free-space swarm (no wind and gravity), as the number of locusts increases, it approaches a crystalline lattice of fixed density if it is H-stable, and in contrast becomes ever more dense if it is catastrophic. Numerical simulations suggest that whether or not a swarm rolls depends on the statistical mechanical properties of the corresponding free-space swarm. For a swarm that is H-stable in free space, gravity causes the group to land and form a crystalline lattice. Wind, in turn, smears the swarm out along the ground until all individuals are stationary. In contrast, for a swarm that is catastrophic in free space, gravity causes the group to land and form a bubble-like shape. In the presence of wind, the swarm migrates with a rolling motion similar to natural locust swarms. The rolling structure is similar to that observed by biologists, and includes a takeoff zone, a landing zone, and a stationary zone where grounded locusts can rest and feed.Comment: 18 pages, 11 figure

GABAergic compensation in connexin36 knock-out mice evident during low-magnesium seizure-like event activity

Gap junctions within the cerebral cortex may facilitate cortical seizure formation by their ability to synchronize electrical activity. To investigate this, one option is to compare wild-type (WT) animals with those lacking the gene for connexin36 (Cx36 KO); the protein that forms neuronal gap junctions between cortical inhibitory cells. However, genetically modified knock-out animals may exhibit compensatory effects; with the risk that observed differences between WT and Cx36 KO animals could be erroneously attributed to Cx36 gap junction effects. In this study we investigated the effect of GABAA-receptor modulation (augmentation with 16 μM etomidate and blockade with 100 μM picrotoxin) on low-magnesium seizure-like events (SLEs) in mouse cortical slices. In WT slices, picrotoxin enhanced both the amplitude (49% increase, p = 0.0006) and frequency (37% increase, p = 0.005) of SLEs; etomidate also enhanced SLE amplitude (18% increase, p = 0.003) but reduced event frequency (25% decrease, p < 0.0001). In Cx36 KO slices, the frequency effects of etomidate and picrotoxin were preserved, but the amplitude responses were abolished. Pre-treatment with the gap junction blocker mefloquin in WT slices did not significantly alter the drug responses, indicating that the reduction in amplitude seen in the Cx36 KO mice was not primarily mediated by their lack of interneuronal gap junctions, but was rather due to pre-existing compensatory changes in these animals. Conclusions from studies comparing seizure characteristics between WT and Cx36 KO mice must be viewed with a degree of caution because of the possible confounding effect of compensatory neurophysiological changes in the genetically modified animals

BCS - BEC crossover at T=0: A Dynamical Mean Field Theory Approach

We study the T=0 crossover from the BCS superconductivity to Bose-Einstein condensation in the attractive Hubbard Model within dynamical mean field theory(DMFT) in order to examine the validity of Hartree-Fock-Bogoliubov (HFB) mean field theory, usually used to describe this crossover, and to explore physics beyond it. Quantum fluctuations are incorporated using iterated perturbation theory as the DMFT impurity solver. We find that these fluctuations lead to large quantitative effects in the intermediate coupling regime leading to a reduction of both the superconducting order parameter and the energy gap relative to the HFB results. A qualitative change is found in the single-electron spectral function, which now shows incoherent spectral weight for energies larger than three times the gap, in addition to the usual Bogoliubov quasiparticle peaks.Comment: 11 pages,12 figures, Published versio

Dilaton constraints and LHC prospects

The Standard Model Higgs searches using the first 1-2 fb-1 of LHC data can be used to put interesting constraints on new scalar particles other than the Higgs. We investigate one such scenario in which electroweak symmetry is broken via strongly coupled conformal dynamics. This scenario contains a neutral scalar dilaton---the Goldstone boson associated with spontaneously broken scale invariance---with a mass below the conformal symmetry breaking scale and couplings to Standard Model particles similar (but not identical) to those of the Standard Model Higgs boson. We translate the LEP and LHC Higgs limits to constrain the dilaton mass and conformal breaking scale. The conformal breaking scale f is constrained to be above 1 TeV for dilaton masses between 145 and 600 GeV, though it can be as low as 400 GeV for dilaton masses below 110 GeV. We also show that (i) a dilaton chi with mass below 110 GeV and consistent with the LEP constraints can appear in gg --> chi --> gamma gamma with a rate up to ~10 times the corresponding Standard Model Higgs rate, and (ii) a dilaton with mass of several hundred GeV is much narrower than the corresponding Standard Model Higgs, leading to improved search sensitivity in chi --> ZZ --> 4l.Comment: 15 pages, 12 figures, References added, Figure 10 modified, Figure 11 adde

New results for a photon-photon collider

We present new results from studies in progress on physics at a two-photon collider. We report on the sensitivity to top squark parameters of MSSM Higgs boson production in two-photon collisions; Higgs boson decay to two photons; radion production in models of warped extra dimensions; chargino pair production; sensitivity to the trilinear Higgs boson coupling; charged Higgs boson pair production; and we discuss the backgrounds produced by resolved photon-photon interactions.Comment: 17 pages, 15 figure