Floristic inventory and quality assessment of Bessey Creek Nature Preserve, Cheboygan County, Michigan, 2011.

Field Biology of PlantsWetlands are habitats that provide critical ecosystem services. As transitional habitats between terrestrial and aquatic environments, wetlands contain plant communities that are typically species rich. One way to measure the composition of plant communities is to inventory the species and conduct a Floristic Quality Assessment (FQA) of the species. Created by Michigan’s Department of Natural Resources (MDNR), the FQA is a tool to evaluate areas that may be of floristic importance and calculate the diversity and species richness of a site. We conducted an FQA of the Bessey Creek Nature Preserve in Cheboygan County, MI, which is owned by the Little Traverse Conservancy (Harbor Springs, MI). The site is located at the mouth of Bessey Creek where it enters Douglas Lake. The preserve contains several plant communities located throughout four habitat zones: the roadside, the swamp, the littoral marsh, and the aquatic shoreline. Our sampling indentified a total of one hundred sixteen species in fifty-four families, with a mean coefficient of conservation of 4.44 for only native species, and 3.62 including introduced species. The preserve has wetlands index of -2.52, signifying that the preserve contains mostly facultative wetland species. Twenty species are considered exotic and are not native to the area. Based on the MDNR’s FQA equations, we calculated the Floristic Quality Index (FQI) of Bessey Creek to be 41.87 when considering only native species and 37.83 when including introduced species. Bessey Creek has a lower FQI than other preserves, ranking below Orchis Fen Preserve (FQI: 49.60) and Kalman Preserve (FQI: 61.70). However, Bessey Creek’s FQI value is above the current threshhold of 35 determined by the MDNR, and is thus considered floristically important to the state of Michigan.Little Traverse Conservancyhttp://deepblue.lib.umich.edu/bitstream/2027.42/89421/1/Dorey_VanDyke_Vogt_2011.pd

Quantum scattering of charged solitons in the complex sine-Gordon model

The scattering of charged solitons in the complex sine-Gordon field theory is investigated. An exact factorizable S-matrix for the theory is proposed when the renormalized coupling constant takes the values $\lambda^{2}_{R}=4\pi/k$ for any integer $k>1$: the minimal S-matrix associated with the Lie algebra $a_{k-1}$. It is shown that the proposed S-matrix reproduces the leading semiclassical behaviour of all amplitudes in the theory and is the minimal S-matrix which is consistent with the semiclassical spectrum of the model. The results are completely consistent with the description of the complex sine-Gordon theory as the SU$(2)/{\rm U}(1)$ coset model at level $k$ perturbed by its first thermal operator.Comment: SWAT-4

Indiscreet Logs: Persistent Diffie-Hellman Backdoors in TLS

Software implementations of discrete logarithm based cryptosystems over finite fields typically make the assumption that any domain parameters they are presented with are trustworthy, i.e., the parameters implement cyclic groups where the discrete logarithm problem is assumed to be hard. An informal and widespread justification for this seemingly exists that says validating parameters at run time is too computationally expensive relative to the perceived risk of a server sabotaging the privacy of its own connection. In this paper we explore this trust assumption and examine situations where it may not always be justified. We conducted an investigation of discrete logarithm domain parameters in use across the Internet and discovered evidence of a multitude of potentially backdoored moduli of unknown order in TLS and STARTTLS spanning numerous countries, organizations, and protocols. Although our disclosures resulted in a number of organizations taking down suspicious parameters, we argue the potential for TLS backdoors is systematic and will persist until either until better parameter hygiene is taken up by the community, or finite field based cryptography is eliminated altogether

An N = 2 Supersymmetric Membrane Flow

We find M-theory solutions that are holographic duals of flows of the maximally supersymmetric N=8 scalar-fermion theory in (2+1) dimensions. In particular, we construct the M-theory solution dual to a flow in which a single chiral multiplet is given a mass, and the theory goes to a new infra-red fixed point. We also examine this new solution using M2-brane probes. The (2+1)-dimensional field theory fixed-point is closely related to that of Leigh and Strassler, while the M-theory solution is closely related to the corresponding IIB flow solution. We recast the IIB flow solution in a more geometric manner and use this to obtain an Ansatz for the M-theory flow. We are able to generalize our solution further to obtain flows with del Pezzo sub-manifolds, and we give an explicit solution with a conifold singularity.Comment: 28 pages; harvma

Exact S-matrices for supersymmetric sigma models and the Potts model

We study the algebraic formulation of exact factorizable S-matrices for integrable two-dimensional field theories. We show that different formulations of the S-matrices for the Potts field theory are essentially equivalent, in the sense that they can be expressed in the same way as elements of the Temperley-Lieb algebra, in various representations. This enables us to construct the S-matrices for certain nonlinear sigma models that are invariant under the Lie ``supersymmetry'' algebras sl(m+n|n) (m=1,2; n>0), both for the bulk and for the boundary, simply by using another representation of the same algebra. These S-matrices represent the perturbation of the conformal theory at theta=pi by a small change in the topological angle theta. The m=1, n=1 theory has applications to the spin quantum Hall transition in disordered fermion systems. We also find S-matrices describing the flow from weak to strong coupling, both for theta=0 and theta=pi, in certain other supersymmetric sigma models.Comment: 32 pages, 8 figure

Soliton quantization and internal symmetry

We apply the method of collective coordinate quantization to a model of solitons in two spacetime dimensions with a global $U(1)$ symmetry. In particular we consider the dynamics of the charged states associated with rotational excitations of the soliton in the internal space and their interactions with the quanta of the background field (mesons). By solving a system of coupled saddle-point equations we effectively sum all tree-graphs contributing to the one-point Green's function of the meson field in the background of a rotating soliton. We find that the resulting one-point function evaluated between soliton states of definite $U(1)$ charge exhibits a pole on the meson mass shell and we extract the corresponding S-matrix element for the decay of an excited state via the emission of a single meson using the standard LSZ reduction formula. This S-matrix element has a natural interpretation in terms of an effective Lagrangian for the charged soliton states with an explicit Yukawa coupling to the meson field. We calculate the leading-order semi-classical decay width of the excited soliton states discuss the consequences of these results for the hadronic decay of the $\Delta$ resonance in the Skyrme model.Comment: 23 pages, LA-UR-93-299

From Effective Lagrangians, to Chiral Bags, to Skyrmions with the Large-N_c Renormalization Group

We explicitly relate effective meson-baryon Lagrangian models, chiral bags, and Skyrmions in the following way. First, effective Lagrangians are constructed in a manner consistent with an underlying large-N_c QCD. An infinite set of graphs dress the bare Yukawa couplings at *leading* order in 1/N_c, and are summed using semiclassical techniques. What emerges is a picture of the large-N_c baryon reminiscent of the chiral bag: hedgehog pions for r > 1/\Lambda patched onto bare nucleon degrees of freedom for r < 1/\Lambda, where the ``bag radius'' 1/\Lambda is the UV cutoff on the graphs. Next, a novel renormalization group (RG) is derived, in which the bare Yukawa couplings, baryon masses and hyperfine baryon mass splittings run with \Lambda. Finally, this RG flow is shown to act as a *filter* on the renormalized Lagrangian parameters: when they are fine-tuned to obey Skyrme-model relations the continuum limit \Lambda --> \infty exists and is, in fact, a Skyrme model; otherwise there is no continuum limit.Comment: Figures included (separate file). This ``replaced'' version corrects the discussion of backwards-in-time baryon

Holographic Renormalization Group Flows: The View from Ten Dimensions

The holographic description of supersymmetric RG flows in supergravity is considered from both the five-dimensional and ten-dimensional perspectives. An N=1* flow of N=4 super-Yang Mills is considered in detail, and the infra-red limit is studied in terms of IIB supergravity in ten dimensions. Depending on the vevs and the direction of approach to the core, the supergravity solution can be interpreted in terms of either 5-branes or 7-branes. Generally, it is shown that it is essential to use the ten-dimensional description in order to study the infra-red asymptotics in supergravity.Comment: Talk presented at the Second Gursey Memmorial Conference; 14 pages; Latex; IOP Macro

Skyrmion Quantization and the Decay of the Delta

We present the complete solution to the so-called ``Yukawa problem'' of the Skyrme model. This refers to the perceived difficulty of reproducing---purely from soliton physics---the usual pseudovector pion-nucleon coupling, echoed by pion coupling to the higher spin/isospin baryons $(I=J=3/2 , 5/2 , \cdots , N_c/2 )$ in a manner fixed by large-$N_c$ group theory. The solution involves surprisingly elegant interplay between the classical and quantum properties of a new configuration, the ``new improved skyrmion''. This is the near-hedgehog obtained by minimizing the usual skyrmion mass functional augmented by an all-important isorotational kinetic term. The numerics are pleasing: a $\Delta$ decay width within a few MeV of its measured value, and furthermore, the higher-spin baryons $(I=J \ge 5/2 )$ with widths so large ($\Gamma > 800 MeV$) that these undesirable large-$N_c$ artifacts effectively drop out of the spectrum, and pose no phenomenological problem. Beyond these specific results, we ground the Skyrme model in the Feynman Path Integral, and set up a transparent collective coordinate formalism that makes maximal use of the $1/N_c$ expansion. This approach elucidates the connection between skyrmions on the one hand, and Feynman diagrams in an effective field theory on the other.Comment: This TeX file inputs the macropackage harvmac.tex . Choose the ``b'' (big) option or equations will overrun