Genetic characterization and population structure of \u3ci\u3eErysiphe pulchra\u3c/i\u3e the causal agent of powdery mildew on \u3ci\u3eCornus florida\u3c/i\u3e in the eastern United States

Cornus florida L. (flowering dogwood) is a deciduous understory tree endemic to the eastern United States. Known for its attractive bracts, C. florida is very popular for its ornamental qualities. After 1995, dogwood powdery mildew caused by Erysiphe pulchra Cooke & Peck reached epidemic levels throughout the C. florida growing region. Initially, both sexual and asexual stages of E. pulchra were regularly observed, but in recent years, the teleomorph has not been seen as often. Fifteen microsatellite loci were used to analyze the genetic diversity and population structure of 174 E. pulchra samples from 10 eastern states. The results of this study indicated low genetic diversity, lack of definitive population structure, and significant linkage disequilibrium within the sampled population. Evidence of a recent bottleneck was also observed. Our results suggest that E. pulchra has become clonal in eastern United States and may be an exotic plant pathogen to North America

SOIL AND BIOSOLID NANO- AND MACRO-COLLOID PROPERTIES AND CONTAMINANT TRANSPORT BEHAVIOR

Despite indications that they are potential contaminant transport systems and threats to groundwater quality, very little effort has been invested in comparing contaminant transport behavior of natural environmental nanocolloids and their corresponding macrocolloid fractions in the presence of As, Se, Pb, and Cu contaminants. This study involved physico-chemical, mineralogical, stability and contaminant-transport characterizations of nano- (\u3c 100 nm) and macro-colloids (100-2000 nm) fractionated from three Kentucky soils and one biosolid waste. Particle size was investigated with SEM/TEM and dynamic light scattering. Surface reactivity was estimated using CEC and zeta potential. Mineralogical composition was determined by XRD, FTIR, and thermogravimetric analyses. Sorption isotherms assessed affinities for Cu2+, Pb2+, AsO3-, and SeO4-2 contaminants, while settling kinetics experiments of suspensions at 0, 2 and 10 mg/L contaminants determined stability and transportability potential. Undisturbed 18x30 cm KY Ashton Loam soil monoliths were also used for transport experiments, involving infusion of 50 mg L-1 colloid suspensions spiked with 2 mg L-1 mixed contaminant loads in unsaturated, steady state, unit gradient downward percolation experiments. Overall, nanocolloids exhibited greater stability over corresponding macrocolloids in the presence and absence of contaminants following specific mineralogy trends. Physicochemical characterizations indicated that extensive organic carbon surface coatings and higher Al/Fe:Si ratios may have induced higher stability in the nanocolloid fractions, in spite of some hindrance by nano-aggregation phenomena. In the transport experiments, nanocolloids eluted significantly higher concentrations of colloids, total, and colloid-bound metals than corresponding macrocolloids. Contaminant elutions varied by colloid type, mineralogy and contaminant, with the following sequences: soil-colloids\u3ebio-colloids, smectitic\u3emixed≥kaolinitic\u3ebiosolid, and Se\u3ePb/Cu≥As. Our findings demonstrate that even though they behave more like nano-aggregates rather than individual nano-particles, nanocolloids may exhibit significantly higher mobility and contaminant transport potential over great distances in subsoil environments than their corresponding macrocolloid fractions

A Note on the Diagonalization of the Discrete Fourier Transform

Following the approach developed by S. Gurevich and R. Hadani, an analytical formula of the canonical basis of the DFT is given for the case $N=p$ where $p$ is a prime number and $p\equiv 1$ (mod 4).Comment: 12 pages, accepted by Applied and Computational Harmonic Analysi

The Genus Palaeagapetus Ulmer (Trichoptera, Hydroptilidae, Ptilocolepinae) in North America

The genus Palaeagapetus Ulmer (Trichoptera, Hydroptilidae, Ptilocolepinae) is revised in North America. Descriptions of the western species, P. nearcticus Banks 1938, are provided with the first descriptions of the female, pupa, larva, egg and case and with notes on food, habitat and annual life cycle. The male and female of the eastern species, P. celsus Ross 1936, are described or redescribed with some ecological notes. Distributions of the two species are summarized

Weevils of the genus Cercopeus Schoenherr from South Carolina, USA (Coleoptera: Curculionidae: Entiminae)

Six new species of the weevil genus Cercopeus Schoenherr are described from South Carolina: C. alexi, C. cornelli, C. femoratus, C. paulus, C. skelleyi, and C. tibialis. Three other species also found in South Carolina are re-described: C. chrysorrhoeus (Say), C. maspavancus Sleeper, and C. strigicollis Sleeper. Keys to known males and females of all 17 species of Cercopeus are given, along with photographs of habitus, leg features, and antennae, and line illustrations of genitalia. Nearly all specimens of the new species were collected from January-March and these species are winter activ