\u3ci\u3eHexagenia Bilineata\u3c/i\u3e (Ephemeroptera: Ephemeridae) Persists at Low Levels of Abundance in the Lower Fox River, Wisconsin

After burrowing mayflies (Hexagenia bilineata) were first noted in the vicinity of the DePere Dam on the Fox River in 1991, adults have been observed in small numbers each summer since then. It is possible that the Fox River population has remained at low levels because of an Allee effect. In addition, it is possible that the population is still limited by poor environmental quality, presumably in the upper layer of sediment inhabited by the larvae. Two other relatively sensitive species associated with benthic habitat, the sea lamprey (Petromyzon marinus) and the lake sturgeon (Acipenser fulvescens), have been observed in the Fox River in recent years. Collectively these species provide an indication of improved environmental conditions, but it is not yet clear that any of the three have established populations capable of successfully reproducing in the lower Fox River on a consistent basis

Design of doubly-complementary IIR digital filters using a single complex allpass filter, with multirate applications

It is shown that a large class of real-coefficient doubly-complementary IIR transfer function pairs can be implemented by means of a single complex allpass filter. For a real input sequence, the real part of the output sequence corresponds to the output of one of the transfer functions G(z) (for example, lowpass), whereas the imaginary part of the output sequence corresponds to its "complementary" filter H(z)(for example, highpass). The resulting implementation is structurally lossless, and hence the implementations of G(z) and H(z) have very low passband sensitivity. Numerical design examples are included, and a typical numerical example shows that the new implementation with 4 bits per multiplier is considerably better than a direct form implementation with 9 bits per multiplier. Multirate filter bank applications (quadrature mirror filtering) are outlined

Theory of magnetic oscillations in Weyl semimetals

Weyl semimetals are a new class of Dirac material that posses bulk energy nodes in three dimensions. In this paper, we study a Weyl semimetal subject to an applied magnetic field. We derive expressions for the density of states, electronic specific heat, and the quantum oscillations of the magnetization, DC conductivity, and thermal conductivity. We find phase shifts in the quantum oscillations that distinguish the Weyl semimetal from conventional three dimensional Schr\"odinger Fermions.Comment: 11 pages, 5 figure

Supersymmetry of consistent massive truncations of IIB supergravity

We discuss the supersymmetry and fermionic sector of the recently obtained consistent truncations of IIB supergravity containing massive modes. In particular, we present the general form of the five-dimensional N = 4 supersymmetry transformations and equations of motion for the fermions arising in the reduction of IIB theory on T^{1,1} which contains all modes invariant under the SU(2) x SU(2) isometry group. The N = 4 reduction can be further truncated to two different N = 2 sub-sectors. For each of these, we present the N = 2 fermionic supersymmetry transformations and corresponding superpotentials. As an application, we obtain the explicit Killing spinors of the Klebanov-Strassler solution and comment on the relation to the ansatz of Papadopoulos and Tseytlin. We also demonstrate the applicability of consistent truncations on squashed Sasaki-Einstein manifolds to a class of flux compactifications, focusing on a recent solution describing the geometry of gaugino condensation on wrapped D7 branes and which possesses dynamic SU(2) structure.Comment: v2: minor typos corrected, references added, v3: significant additions to include fermion equations of motion, journal versio

Impact of Electron-Phonon Coupling on Near-Field Optical Spectra

The finite momentum transfer ($\boldsymbol{q}$) longitudinal optical response $\sigma^L(\boldsymbol{q},\omega)$ of graphene has a peak at an energy $\omega=\hbar v_F q$. This corresponds directly to a quasiparticle peak in the spectral density at momentum relative to the Fermi momentum $k_F -q$. Inclusion of coupling to a phonon mode at $\omega_E$ results, for $\omega<|\omega_E|$, in a constant electron-phonon renormalization of the bare bands by a mass enhancement factor $(1+\lambda)$ and this is followed by a phonon kink at $\omega_E$ where additional broadening begins. Here we study the corresponding changes in the optical quasiparticle peaks which we find to continue to directly track the renormalized quasiparticle energies until $q$ is large enough that the optical transitions begin to sample the phonon kink region of the dispersion curves where linearity in momentum is lost in the renormalized Dirac Fermion dispersion curves and the correspondence to a single quasiparticle energy is lost. Nevertheless there remains in $\sigma^L(\boldsymbol{q},\omega)$ features analogous to the phonon kinks of the dispersion curves which are observable through variation of $q$ and $\omega$.Comment: 6 pages, 5 figure