Taxonomy of the Simulium perflavum species-group (Diptera: Simuliidae) : with description of a new species from Brazil

The larva, pupa, male, and female of Simulium trombetense n. sp. are described and illustrated. This species was collected in the Brazilian Amazon region in the states of Amapa, Amazonas, Para, and Roraima near the edges ofthe crystalline basement-rock formation ofthe Pre-Cambrian Guiana Shield. Keys for larvae, pupae, males, and females of species in the Simulium perflauum Species-Group are presented, as well as new observations on adult, pupal, and larval characters. Evidence is given to support the species status of S. maroniense Floch and Abonnenc, previously considered synonymous with S. rorotaense Floch and Abonnenc

BLACK FLY SURVEY OF A WHOOPING CRANE REINTRODUCTION AREA IN EASTERN WISCONSIN

Nest desertion due to harassment by black flies (Simulium annulus and S. johannseni) during incubation has been a major factor inhibiting success of the reintroduced Eastern Migratory Population of whooping cranes (Grus americana). To avoid this problem, which was prevalent in the core reintroduction area in central Wisconsin, the Whooping Crane Eastern Partnership changed the primary reintroduction area to eastern Wisconsin in 2011. However, a 2010 assessment of black flies in that area had concentrated predominantly on the southern portion of the new area. In 2017-2018, we collected the first samples of black flies in Green Lake County, including a new primary reintroduction site on White River Marsh (WRM), by sweep-netting over taxidermic crane mounts on artificial nests. In 2017, peak mean numbers of S. johannseni per sample at WRM and Grand River Marsh were 3,077 (maximum 6,838) and 891specimens, respectively. Numbers of black flies of this magnitude (and lower) collected during sampling by the same technique have been associated with nest desertion at Necedah National Wildlife Refuge in the core area. Numbers of S. johannseni were much lower in Green Lake County in 2018, and S. annulus was not abundant in either year. In contrast, an additional survey of black flies at WRM in 2021 recorded numbers of S. annulus potentially large enough to affect whooping crane nesting. Multi-year studies of black flies at WRM and other new reintroduction sites, coordinated with monitoring of whooping crane nesting, are needed to ascertain the impact of black flies and implement plans to promote success of this whooping crane population

Robust preconditioners for a new stabilized discretization of the poroelastic equations

In this paper, we present block preconditioners for a stabilized discretization of the poroelastic equations developed in [45]. The discretization is proved to be well-posed with respect to the physical and discretization parameters, and thus provides a framework to develop preconditioners that are robust with respect to such parameters as well. We construct both norm-equivalent (diagonal) and field-of-value-equivalent (triangular) preconditioners for both the stabilized discretization and a perturbation of the stabilized discretization that leads to a smaller overall problem after static condensation. Numerical tests for both two- and three-dimensional problems confirm the robustness of the block preconditioners with respect to the physical and discretization parameters

Effects of Acoustic Scattering at Rough Surfaces on the Sensitivity of Ultrasonic Inspection

Ultrasonic inspection of ordinary samples with more or less rough surfaces is an everyday problem in industrial NDE. Contact techniques require flat or other regular (e. g., cylindrical) surfaces of negligible roughness with respect to the acoustic wavelength. Immersion techniques are less susceptible to surface topography, but they still require that the surface radius be larger than the beam diameter and the surface roughness be comparable or less than the wavelength in the immersion fluid. This difference is due to the fact that in immersion inspection surface irregularities do not significantly reduce the energy transmission into the specimen but rather randomize the field through incoherent scattering. Figure 1 shows the schematic diagram of ultrasonic inspection of a rough specimen by the immersion method. The probability of detection of a given flaw is ultimately limited by the signal-to-noise ratio produced at the receiver. The flaw signal results from coherent reflection from a single, relatively large and strong scatterer. In comparison, the noise is incoherent scattering from a large number of randomly distributed, relatively small and weak scatterers such as material inhomogeneities or geometrical irregularities. Surface roughness can substantially reduce the signal-to-noise ratio with respect to an otherwise similar smooth sample. First, surface roughness attenuates the coherent flaw signal much more than the incoherent material noise [1,2]. Second, surface roughness increases the overall noise level by adding another incoherent component to the material noise. This paper discusses the adverse effect of the excess surface noise on ultrasonic flaw detection in rough samples

Black fly

The South Carolina Department of Natural Resources published guides to many threatened animals living in the state. This guide gives information about the Black fly, including description, status, habitat, conservation challenges & recommendations, and measures of success

Spectral properties of fractional differentiation operators

We consider fractional differentiation operators in various senses and show that the strictly accretive property is the common property of fractional differentiation operators. Also we prove that the sectorial property holds for differential operators second order with a fractional derivative in the final term, we explore a location of the spectrum and resolvent sets and show that the spectrum is discrete. We prove that there exists a two-sided estimate for eigenvalues of the real component of operators second order with the fractional derivative in the final term.Comment: The research results were discussed and presented at the 8th International Conference on Differential and Functional Differential Equations. Moscow, Russia, August 13-20, 201

Antiferromagnetic structure and electronic properties of BaCr2As2 and BaCrFeAs2

The chromium arsenides BaCr2As2 and BaCrFeAs2 with ThCr2Si2 type structure (space group I4/mmm; also adopted by '122' iron arsenide superconductors) have been suggested as mother compounds for possible new superconductors. DFT-based calculations of the electronic structure evidence metallic antiferromagnetic ground states for both compounds. By powder neutron diffraction we confirm for BaCr2As2 a robust ordering in the antiferromagnetic G-type structure at T_N = 580 K with mu_Cr = 1.9 mu_B at T = 2K. Anomalies in the lattice parameters point to magneto-structural coupling effects. In BaCrFeAs2 the Cr and Fe atoms randomly occupy the transition-metal site and G-type order is found below 265 K with mu_Cr/Fe = 1.1 mu_B. 57Fe Moessbauer spectroscopy demonstrates that only a small ordered moment is associated with the Fe atoms, in agreement with electronic structure calculations with mu_Fe ~ 0. The temperature dependence of the hyperfine field does not follow that of the total moments. Both compounds are metallic but show large enhancements of the linear specific heat coefficient gamma with respect to the band structure values. The metallic state and the electrical transport in BaCrFeAs2 is dominated by the atomic disorder of Cr and Fe and partial magnetic disorder of Fe. Our results indicate that Neel-type order is unfavorable for the Fe moments and thus it is destabilized with increasing iron content.Comment: 14 pages, 14 figures, submitted to Physical Review