Ecology and Host Associations of \u3ci\u3eHistiogaster Arborsignis\u3c/i\u3e (Acari: Acaridae) in the Great Lakes Region, Particularly in the Huron Mountains of Northern Michigan

Histiogaster arborsignis is recorded from subcortical habitats and fungal fruiting bodies in the Huron Mountains of northern Michigan. Deutonymphs were collected from 15 species of Coleoptera, Hymenoptera and Diptera. Additional host and locality records for this species are provided from other areas in the Great Lakes region

Systematics, Ecology and Host Associations of \u3ci\u3eNaiadacarus\u3c/i\u3e (Acari: Acaridae) in the Great Lakes Region

Naiadacarus arboricola Fashing, is reported from adults collected from water-filled treeholes and deutonymphs phoretic on Mallota species, Eristalis bardus and Somula decora (Diptera: Syrphidae) from Michigan, Illinois, and New York. Naiadacarus fashingi, new species, is described from deutonymphs phoretic on Brachypalpus oarus and seven other species of Syrphidae from Michigan, New York and New Jersey. Naiadacarus mydophilus, new species, is described from deutonymphs phoretic on Brachypalpus oarus from Michigan. Based upon known biologies of host insects and other mite species which utilize these hosts, it is hypothesized that N. lashingi and N. mydophilus may inhabit wet decaying wood andior moist treeholes rather than water-filled treeholes. Naiadacarus is hypothesized to be closely related to the genera Schwiebea, Histiogaster and Thyreophagus. The subfamily name Naiadacarinae is placed in synonymy with Rhizoglyphinae

Ontogeny and Systematics of the Genus \u3ci\u3eCerophagus\u3c/i\u3e (Acari: Gaudiellidae), Mites Associated With Bumblebees

Nymphs and adults of Cerophagus nearcticus n. sp. are described from the nest of Bombus terricola occidentalis in California and phoretic associations with B. impatiens in Michigan and New York. On the basis of adult morphology, the genus Cerophagopsis is removed from synonymy with Cerophagus and retained in the family Acaridae, while Cerophagus is transferred to the family Gaudiellidae. The genus Rhypoglyphus is considered a junior subjec­tive synonym of Cerophagopsis. The genera of Gaudiellidae are noted and the genus Trigonacoptes is considered a junior subjective synonym of Gaudiella

Optical system facilitates inspection of printed circuit boards

Optical comparator method determines the quality and registration of surface features of double-sided printed circuit boards. Color-coded superimposed images of both sides of a printed circuit board are presented to view, clearly showing details and registration of the circuitry

Approaches to rotor fragment protection

Key airworthiness design criteria considerations for fragment protection as found in various FAA requirements in FAR Parts 25 and 33, and in interpretive 8110 orders are reviewed. The impact of providing aircraft armor in lieu of engine armor for typical three- and four-engine wide bodied transports for protection within the length of the engine case as well as from fragments exiting ahead of the enlet engine inlet flange is assessed. For protection within the length of the engine case, armor weight penalties, plus fuel burned and dollar cost of carrying the armor protection are defined. Immediately ahead of the inlet flange, direct tangential impacts are predominant, but further forward, rebound impacts predominate. Armor thickness requirements and fuel cost impact of protection are given

Two New Genera of Hemisarcoptidae (Acari: Astigmata) From the Huron Mountains of Northern Michigan

Two new genera and species of Hemisarcoptidae, Superioropus huronmontanus and Huronopus michiganensis are described from deutonymphs phoretic on ichneumonid wasps from the Huron Mountains, Marquette County, Michigan

Occurrence of the Bat Tick, \u3ci\u3eOrnithodoros Kelleyi\u3c/i\u3e (Acari: Argasidae), in Michigan

The bat tick, Ornithodoros kelleyi, is recorded from Michigan for the first time. A single female was collected in a building on the University of Michigan campus in Ann Arbor

EMTP based stability analysis of space station electric power system in a test bed environment

The Space Station Freedom Electric Power System (EPS) will convert solar energy into electric energy and distribute the same using an 'all dc', Power Management and Distribution (PMAD) System. Power conditioning devices (dc to dc converters) are needed to interconnect parts of this system operating at different nominal voltage levels. Operation of such devices could generate under damped oscillations (instability) under certain conditions. Criteria for instability are examined and verified for a single device. Suggested extension of the criteria to a system operation is examined by using the EMTP model of the PMAD DC test bed. Wherever possible, data from the test bed is compared with the modeling results

The use of oil for in-flight flow visualization

Oil was used to visualize inflight aerodynamic characteristics such as boundary layer transition, shock wave location, regions of separated flow, and surface flow direction. The technique, which is similar to wind tunnel oil-flow testing, involves an oil mixture to test aircraft before takeoff. After takeoff, the airplane climbs immediately to the test altitude and photographs are taken. The developmental experience is summarized, several examples of inflight oil-flow photographs are presented and discussed, and an approach for potential users of the technique is presented

Improved tRNA prediction in the American house dust mite reveals widespread occurrence of extremely short minimal tRNAs in acariform mites

<p>Abstract</p> <p>Background</p> <p>Atypical tRNAs are functional minimal tRNAs, lacking either the D- or T-arm. They are significantly shorter than typical cloverleaf tRNAs. Widespread occurrence of atypical tRNAs was first demonstrated for secernentean nematodes and later in various arachnids. Evidence started to accumulate that tRNAs of certain acariform mites are even shorter than the minimal tRNAs of nematodes, raising the possibility that tRNAs lacking both D- and T-arms might exist in these organisms. The presence of cloverleaf tRNAs in acariform mites, particularly in the house dust mite genus <it>Dermatophagoides</it>, is still disputed.</p> <p>Results</p> <p>Mitochondrial tRNAs of <it>Dermatophagoides farinae </it>are minimal, atypical tRNAs lacking either the T- or D-arm. The size (49-62, 54.4 ± 2.86 nt) is significantly (p = 0.019) smaller than in <it>Caenorhabditis elegans </it>(53-63, 56.3 ± 2.30 nt), a model minimal tRNA taxon. The shortest tRNA (49 nt) in <it>Dermatophagoides </it>is approaching the length of the shortest known tRNAs (45-49 nt) described in other acariform mites. The D-arm is absent in these tRNAs, and the inferred T-stem is small (2-3 bp) and thermodynamically unstable, suggesting that it may not exist in reality. The discriminator nucleotide is probably not encoded and is added postranscriptionally in many <it>Dermatophagoides </it>tRNAs.</p> <p>Conclusions</p> <p>Mitochondrial tRNAs of acariform mites are largely atypical, non-cloverleaf tRNAs. Among them, the shortest known tRNAs with no D-arm and a short and unstable T-arm can be inferred. While our study confirmed seven tRNAs in <it>Dermatophagoides </it>by limited EST data, further experimental evidence is needed to demonstrate extremely small and unusual tRNAs in acariform mites.</p