bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of a Two-Stage Injection Process to Reduce the Effects of In-Plane Resin Flow
Authors: Larsen Erik , Cairns Douglas , Mandell John , Samborsky Daniel
Published: March 2009

This paper is a discussion of a manufacturing technique that reduces dependency on in-plane resin flow, allowing greatly reduced injection times, increased injected resin volume per port (reducing the number of ports required), and allows relatively higher fiber volume content. This method uses a two-stage injection process. The first stage injects resin into a vacuum evacuated “pool” outside of the plane of the fabric. Pressure is then applied outside of a flexible film, forcing resin into the fabric in the thickness direction. Since resin is not required to flow in the plane of the fabric, relatively high volumetric flow rates are possible during the injection stage. The hydrostatic pressure on the flexible film results in part-to-part and spatially consistent high volume content. This process has also shown to be less sensitive to fabric and manufacturing inconsistencies than traditional two-sided mold RTM, and has been used to successfully manufacture parts using difficult-to-RTM materials such as bonded fabrics. Drawbacks of this process include increased mold and process complexities, poor surface finish on one side of the part, and increased complexity of process tuning.
Does harmonicity explain children’s cue weighting of fricative-vowel syllables?
Authors: Nittrouer Susan , Lowenstein Joanna H.
Published: March 2009

When labeling syllable-initial fricatives, children have been found to weight formant transitions more and fricative-noise spectra less than adults, prompting the suggestion that children attend more to the slow vocal-tract movements that create syllabic structure than to the rapid gestures more closely aligned with individual phonetic segments. That explanation fits well with linguistic theories, but an alternative explanation emerges from auditory science: Perhaps children attend to formant transitions because they are found in voiced signal portions, and so formants share a common harmonic structure. This work tested that hypothesis by using two kinds of stimuli lacking harmonicity: sine-wave and whispered speech. Adults and children under 7years of age were asked to label fricative-vowel syllables in each of those conditions, as well as natural speech. Results showed that children did not change their weighting strategies from those used with natural speech when listening to sine-wave stimuli, but weighted formant transitions less when listening to whispered stimuli. These findings showed that it is not the harmonicity principle that explains children’s preference for formant transitions in phonetic decisions. It is further suggested that children are unable to recover formant structure when those formants are not spectrally prominent and/or are noisy.
Considering distortion product otoacoustic emission fine structure in measurements of the medial olivocochlear reflex
Authors: Abdala Carolina , Mishra Srikanta K. , Williams Tracy L.
Published: March 2009

In humans, when the medial olivocochlear (MOC) pathway is activated by noise in the opposite ear, changes in distortion product otoacoustic emission (DPOAE) level, i.e., the MOC reflex, can be recorded in the test ear. Recent evidence suggests that DPOAE frequency influences the direction (suppression/enhancement) of the reflex. In this study, DPOAEs were recorded at fine frequency intervals from 500 to 2500 Hz, with and without contralateral acoustic stimulation (CAS) in a group of 15 adults. The MOC reflex was calculated only at DPOAE frequencies corresponding to peaks in the fine structure. Additionally, inverse fast-Fourier transform was conducted to evaluate MOC effects on individual DPOAE components. Results show the following: (1) When considering peaks only, the mean MOC reflex was −2.05dB and 97% of observations reflected suppression, (2) CAS reduced distortion characteristic frequency component levels more than overlap component levels, and (3) CAS produced an upward shift in fine structure peak frequency. Results indicate that when the MOC reflex is recorded at DPOAE frequencies corresponding to fine structure maxima (i.e., when DPOAE components are constructive and in phase), suppression is reliably observed and level enhancement, which probably reflects component mixing in the ear canal rather than strength of the MOC reflex, is eliminated.
Use of stimulus-frequency otoacoustic emissions to investigate efferent and cochlear contributions to temporal overshoot
Authors: Keefe Douglas H. , Schairer Kim S. , Ellison John C. , Fitzpatrick Denis F. , Jesteadt Walt
Published: March 2009

Behavioral threshold for a tone burst presented in a long-duration noise masker decreases as the onset of the tone burst is delayed relative to masker onset. The threshold difference between detection of early- and late-onset tone bursts is called overshoot. Although the underlying mechanisms are unclear, one hypothesis is that overshoot occurs due to efferent suppression of cochlear nonlinearity [von Klitzing, R., and Kohlrausch, A. (1994). J. Acoust. Soc. Am. 95, 2192–2201]. This hypothesis was tested by using overshoot conditions to elicit stimulus-frequency otoacoustic emissions (SFOAEs), which provide a physiological measure of cochlear nonlinearity. SFOAE and behavioral thresholds were estimated using a modified maximum-likelihood yes-no procedure. The masker was a 400-ms “frozen” notched noise. The signal was a 20-ms, 4-kHz tone burst presented at 1 or 200 ms after the noise onset. Behavioral overshoot results replicated previous studies, but no overshoot was observed in SFOAE thresholds. This suggests that either efferent suppression of cochlear nonlinearity is not involved in overshoot, or a SFOAE threshold estimation procedure based on stimuli similar to those used to study behavioral overshoot is not sensitive enough to measure the effect.
Comparing two proposed measures of cochlear mechanical filter bandwidth based on stimulus frequency otoacoustic emissions
Authors: Lineton Ben , Wildgoose Catriona M. B.
Published: March 2009

It has been hypothesized that the sharpness of the cochlear mechanical filter is related to two measures based on stimulus frequency otoacoustic emissions (SFOAEs). The first is the group delay of the SFOAE; the second is the bandwidth of the SFOAE two-tone suppression isoinput tuning characteristic. A corollary of this is that natural variability in cochlear mechanical bandwidth within a population would lead to a positive correlation between these two SFOAE-based measures of tuning within that population. To test this prediction, SFOAE group delay and SFOAE two-tone suppression isoinput tuning characteristics were measured in a sample of 16 audiometrically normal subjects. Contrary to the prediction, no statistically significant correlation was found between the two bandwidth measures. Cochlear model simulations were used to aid the interpretation of this result. These suggested that a positive correlation between the two measures is expected, but that it may well be too weak to detect with the given sample size, due to the influence on the SFOAE measures of random inhomogeneities in basilar membrane impedance.
Off-axis effects on the multi-pulse structure of sperm whale coda clicks
Authors: Schulz Tyler M. , Whitehead Hal , Rendell Luke
Published: March 2009

Sperm whale (Physeter macrocephalus) clicks have a multi-pulse structure, a result of the reflection of sound energy between air sacs in the spermaceti organ. Although previous research revealed that usual clicks (used for echolocation) recorded away from a vocalizing whale’s longitudinal axis have waveforms with poorly defined pulse structures, it has been unknown whether sperm whale coda clicks (used for communication) show similar off-axis effects. To address this knowledge gap, a hydrophone array was used to localize vocalizing sperm whales, and the waveforms of coda clicks recorded from different aspects were examined. Coda clicks recorded close to the whale’s acoustic axis showed well-defined multi-pulsed waveforms, while those recorded off-axis did not. As for usual clicks, this suggests that sound energy radiates directly into the water upon reflection off the frontal sac.
Use of acoustic navigation signals for simultaneous localization and sound-speed estimation
Authors: Skarsoulis E. K. , Piperakis G. S.
Published: March 2009

The possibility of exploiting low-resolution acoustic signals used for the navigation of Lagrangian floats to simultaneously estimate the speed of sound is studied. Acoustic navigation of Lagrangian floats is regularly carried out by measuring travel times from three fixed stations assuming a known value for the speed of sound. The sound speed is considered here as a variable of the problem to be estimated from the travel-time data simultaneously with the horizontal location of the float. The estimation problem is linearized and solved analytically, and closed-form expressions for the sound-speed estimation errors are derived. Typical acoustic navigation (RAFOS) signals are characterized by limited time resolution (0.2s) challenging the accuracy of sound-speed estimation, depending on the location of the float with respect to the fixed stations. By exploiting travel-time data from multiple floats, the sound-speed estimation accuracy can be increased, which reflects in higher localization accuracy as well. In the case of a single float improved sound-speed estimates and localization results can be obtained by combining travel-time data from different float locations. Numerical results verify the theoretical error estimates and demonstrate the efficiency of the method.
Internal noise reduction from dependent signal mixtures using microphones and a piezoelectric device under blind condition
Authors: Matsumoto Mitsuharu , Hashimoto Shuji
Published: March 2009

The acoustical array composed of microphones and piezoelectric devices can reduce internally generated noise from the system such as a machine, a vehicle, or a robot. However, when the acoustical array combining microphones and piezoelectric devices is employed, it is necessary to estimate the gains of microphones and piezoelectric devices concerning the system that generates the noise in advance. The aim of this paper is to simplify this process, that is, to reduce internally generated noise without preknowledge concerning the gains of microphones and piezoelectric devices. Although the proposed method handles an anechoic mixing, it has some merits that complement the other typical blind source separation algorithms. In this paper, the problem is first formulated. The assumptions and the methodology of the proposed method are then given with some experimental results.
Strain-Dependent Variation in 18S Ribosomal DNA Copy Numbers in
Aspergillus fumigatus
Authors: Herrera M. L. , Vallor A. C. , Gelfond J. A. , Patterson T. F. , Wickes B. L.
Published: March 2009

Enumerating
Aspergillus fumigatus
CFU can be challenging since CFU determination by plate count can be difficult. CFU determination by quantitative real-time PCR (qPCR), however, is becoming increasingly common and usually relies on detecting one of the subunits of the multicopy rRNA genes. This study was undertaken to determine if ribosomal DNA (rDNA) copy number was constant or variable among different
A. fumigatus
isolates.
FKS1
was used as a single-copy control gene and was validated against single-copy (
pyrG
and
ARG4
) and multicopy (
arsC
) controls. The copy numbers of the 18S rDNA subunit were then determined for a variety of isolates and were found to vary with the strain, from 38 to 91 copies per genome. Investigation of the stability of the 18S rDNA copy number after exposure to a number of different environmental and growth conditions revealed that the copy number was stable, varying less than one copy across all conditions, including in isolates recovered from an animal model. These results suggest that while the ribosomal genes are excellent targets for enumeration by qPCR, the copy number should be determined prior to using them as targets for quantitative analysis.
Patterns of succinate dehydrogenase activity in a leg muscle of the domestic duck during postnatal development
Authors: Swatland H. J.
Published: March 2009

Transverse sections of iliotibialis cranialis from male Muscovy ducks were reacted for histochemical demonstration of myofibrillar adenosine triphosphatase (ATPase) and for succinate dehydrogenase (SDH) activities. The distribution of SDH activity within muscle fibers was measured with a microscope photometer and a computer-controlled scanning stage. From 1 to 10 weeks after hatching, the average SDH activity across muscle fiber areas decreased. All fiber types exhibited a decline of SDH activity in their central axis. However, fibers with strong ATPase and weak SDH concurrently developed stronger SDH activity in their subsarcolemmal zone. Thus, centripetal radial gradients of SDH activity within fibers became more negative as muscle fibers grew in cross-sectional area.
Removal trapping studies of dispersal in Peromyscus leucopus
Authors: Krohne David T. , Miner Mark S.
Published: March 2009

Removal trapping was used to study the patterns of dispersal in a population of Peromyscus leucopus inhabiting old-growth eastern deciduous forest. Dispersers colonizing an artificial dispersal sink were biased toward males compared with nearby resident populations. Both male and female dispersers were biased toward younger, nonreproductive classes. There was no relationship between the number of dispersers or the rate of dispersal and density. In comparison with previous studies of dispersal in these same populations, removal trapping appeared to confirm the lack of any significant relationship between dispersal and density. However, it is apparent that removal trapping studies induce mice to disperse that otherwise might not have moved.
Fluctuating asymmetry in fishes inhabiting acidified and unacidified lakes
Authors: Jagoe Charles H. , Haines Terry A.
Published: March 2009

Fluctuating asymmetry, the random deviation from perfect bilateral symmetry owing to developmental perturbation, has been used in a number of studies to quantify stress during early life. Decreasing pH and related changes in aquatic environments owing to input of anthropogenic acids have been demonstrated to be physiologically stressful to many fish species. Therefore, a link between environmental acidification and fluctuating asymmetry was postulated. Brook trout (Salvelinus fontinalis), white sucker (Catostomus commersoni), and lake chub (Couesis plumbeus) were collected from lakes over a wide range of pH values. Use of several species allowed separate consideration of environmental and genetic effects. Depending on species, 15 to 20 paired meristic and morphometric characters were scored for the left and right sides of each individual. Differences between sides were calculated and analyzed by a variety of statistical methods. Most characters examined were not significantly more asymmetric in acidified lakes. However, one or two characters in each species were more asymmetric in lakes of lower pH. Relative overall asymmetry in brook trout was related to parameters that changed with acidification. The small number of locations sampled precluded such an analysis in the other two species. The results are consistent with the hypothetical link between environmental stress by acidification and increased fluctuating asymmetry, but the connection is much weaker than expected. This finding, the need for large sample sizes, and the lack of a definite causal link, severely limits the utility of this type of analysis in assessing the level of stress in fish populations.
The food habits and distribution of Northern Gannets, Sula bassanus, off eastern Newfoundland and Labrador
Authors: Kirkham I. R. , McLaren P. L. , Montevecchi W. A.
Published: March 2009

The marine distribution of Northern Gannets in the southern Labrador Sea and western North Atlantic Ocean was studied by aerial surveys over a 7-month period in 1981. Gannets were seen on every biweekly aerial survey from mid-April to the end of October. Densities were highest within a 60 km radius of Funk Island, but few gannets were seen offshore outside this radius. Before July, most gannets were seen south of Labrador (52°N), but as the breeding season advanced, gannet densities increased in northern areas. Densities in most areas peaked during mid-July. From 1977 to 1982 we collected food samples from gannets in the colony on Funk Island, Newfoundland. A broad spectrum of prey are taken. Mackerel and herring, prey that are associated with warm water, appear to be preferred owing to their large sizes and high energy densities. Prey occurrence in gannet food samples was associated with the time of spawning (capelin) and migration near Funk Island (herring and mackerel). The northernmost region of warm and cold water mixing appears to be the main factor limiting the northern distribution of gannets in the western North Atlantic Ocean.
Parasitoid–host relationship between Trioxys (Binodoxys) indicus Subba Rao &Sharma (Hymenoptera: Aphidiidae) and Aphis craccivora Koch (Hemiptera: Aphididae): effect of host plants on the area of discovery of the parasitoid
Authors: Kumar Arvind , Tripathi C. P. M.
Published: March 2009

This paper elucidates the effect of different host plants on the area of discovery of the parasitoid Trioxys (Binodoxys) indicus, which decreases linearly with the increase of parasitoid density. This decrease is minimum in aphids reared on Cajanus cajan followed by those reared on Dolichos lablab and Solanum melongena, but the killing power (k value) increases significantly in all the tested host plants, being maximum in aphids reared on C. cajan followed by those reared on D. lablab and S. melongena. However, when the host density increases, the area of discovery and k value (high in C. cajan aphids followed by D. lablab and S. melongena aphids) increases up to 50 hosts and thereafter decreases. The leaf texture of the host plants and the interference between the parasitoids at higher densities is suggested as a cause for this type of behavioural response which is explained by the population model of M. P. Hassell and G. C. Varley. For the suppression of Aphis craccivora population, it is suggested that the parasitoid and the host ratio may be 1:50 and for the mass rearing of the parasitoid, when C. cajan is not available in the field, D. lablab may be used as an alternative host plant.
Identification of Diphyllobothrium dendriticum and Diphyllobothrium latum from some freshwater fishes of central Canada
Authors: Dick T. A. , Poole B. C.
Published: March 2009

Two species of Diphyllobothrium occurred in Quigly Lake, Manitoba: plerocercoids of D. dendriticum encapsulated on the viscera of shallow water cisco (Coregonus artedii) and lake whitefish (Coregonus clupeaformis) and plerocercoids of D. latum unencapsulated in the muscle of walleye (Stizostedion vitreum vitreum) and northern pike (Esox lucius). Adult D. dendriticum were obtained through experimental infections of both herring gulls (Larus argentatus) and hamsters (Mesocricetus auratus), but adult D. latum developed experimentally only in the latter. The scolex position of adult D. dendriticum was more anterior than D. latum in the small intestine of hamsters. Eggs were present in utero and in the faeces by days 10–11 postinfection (PI) for D. dendriticum in hamsters and gulls and by day 17 PI for D. latum in hamsters. Adult D. dendriticum grew longer and had more segments in gulls than in hamsters. The neck length of adult D. latum was at least five times greater than the neck length of adult D. dendriticum in hamsters by day 17 PI. Viewed laterally, the seminal vesicle in adult D. dendriticum was dorsal to the cirrus sac, while in D. latum, the seminal vesicle was dorsocaudal to the cirrus sac. A constriction between segments was noted for adult D. latum only.
Tropical freshwater Copepoda from Papua, New Guinea, Burma, and Costa Rica, including a new species of Mesocyclops from Burma
Authors: Dussart B. H. , Fernando C. H.
Published: March 2009

A new subspecies, Eucyclops birmanus aequatorialis ssp. nov., is described from Papua, New Guinea; Mesocyclops pehpeiensis, known from China, is recorded from Burma, Sri Lanka, and Malaysia; and a new species, Mesocyclops restrictus sp. nov., is described from Burma. Based on abundant material from Costa Rica, the status of Diaptomus dorsalis Marsh is reexamined.
Observations on the migrations of North Pacific humpback whales (Megaptera novaeangliae)
Authors: Darling James D. , McSweeney Daniel J.
Published: March 2009

Migratory destinations of northeast Pacific humpback whales (Megaptera novaeangliae) were determined by repeat sightings of photographically identified individuals, using the black and white pigment patterns on the ventral side of the flukes. Individuals identified between 1975 and 1982 included 1056 in Hawaii, 420 in southeast Alaska, 54 in Prince William Sound, Alaska, 8 in British Columbia, and 12 in the Revillagigedo Islands, Mexico. Of these, 51 were found in Hawaii and southeast Alaska, 8 in Hawaii and Prince William Sound, 1 in Hawaii and British Columbia, and 1 in Mexico and Hawaii. Some travelled for four, five, and six successive seasons between Hawaii and southeast Alaska. One whale was found in British Columbia one summer and in southeast Alaska the next; the same individuals were commonly found off both Kona, Hawaii, and West Maui in winter. The study suggests that separate summer feeding areas may exist in the northeast Pacific where individuals prefer to feed. Migratory connections suggest that all humpbacks in the eastern North Pacific are of the same stock.
Nonrandom mate choice by females of Drosophila pseudoobscura: a case of outbreeding avoidance?
Authors: Harmsen R. , McKay L. R.
Published: March 2009

Relative mating success of genetically different males of Drosophila pseudoobscura was measured with five female strains using an experimental set-up consisting of a mating chamber containing 20 females of one strain and a total of 20 males of two different strains. No evidence was found indicating negative assortative mating, neither of the direct type, nor of the "rare male" type. Some strains, however, displayed strong positive assortative mating, as males of the same strain as the females were significantly more successful in obtaining copulations than were males of another strain present in the mating chambers. Deviations from random mating can be interpreted as the result of some males possessing higher levels of "vigour," but an alternative explanation is favoured, one involving female choice. Experimental results do indicate that the orange-eyed mutant flies, used as one of the male strains in all experiments, did have a relatively low level of courtship vigour, but not low enough to account for more than a small fraction of the differential mating success observed in some of the experiments.
Electrophoretic identification of Ambystoma laterale and Ambystoma texanum as well as their diploid and triploid interspecific hybrids (Amphibia: Caudata) on Pelee Island, Ontario
Authors: Bogart James P. , Licht Lawrence E. , Oldham Michael J. , Darbyshire Stephen J.
Published: March 2009

Ambystoma salamanders from Pelee Island, Ontario, were compared with mainland populations of A. jeffersonianum, A. laterale, and A. texanum using erythrocyte area measurements, chromosome counts, and electrophoretic analysis of proteins coded by 32 loci. The mainland species are characterized by relatively low heterozygosity (H = 0.053–0.11) and high Nei's genetic distances (D = 0.896–1.067). Nine diagnostic loci were found in A. jeffersonianum and five in each of A. laterale and A. texanum. Two loci (SOD-1 and GOT-1) diagnose all three mainland species and provide gene dosage for assessing genome contributions of A. laterale and A. texanum in Pelee Island salamanders. Diploid and triploid female A. texanum × A. laterale hybrids as well as A. laterale and A. texanum occur on Pelee Island.
Localization and distribution of antigens related to calcium-rich deposits in the gills of several freshwater bivalves
Authors: Steffens W. L. , Silverman H. , Dietz T. H.
Published: March 2009

In the gills of freshwater unionid mussels, calcium concretions may account for up to 50% of the dry weight of the gill and are composed primarily of calcium phosphate with an associated glycoprotein. The role of these structures in relation to calcium physiology of bivalves is unknown. A study of the origin and distribution of these structures and their possible relationship to specific organ systems or tissue types was undertaken. An antiserum to decalcified concretions was prepared and utilized in indirect immunofluorescence studies on fresh-frozen sections of excised gill. Electron microscopy was employed to examine areas of interest revealed by the immunofluorescence microscopy. Calcium concretions provided the bulk of the fluorescence when the sections were examined. In addition to the concretions, other structures including the chitinous rods of the gill filaments, and nerve tracts intimately associated with the concretions also bound the antiserum, suggesting the possibility of some shared antigens. Some previously undescribed cells, also found to react with the antisera, were shown by electron microscopy to contain what appears to be concretion material in stages of assembly and likely represent the synthesis site of the concretions in the gill. Antisera were produced from isolated concretions of two different genera; each reacted similarly when tested against tissues from several different unionid species. These data suggest a similar composition for calcium phosphate concretions within the Unionidae.
Morphology and distribution of antennal sensilla in the female and male clothes moth, Tineola bisselliella Humm. (Lepidoptera: Tineidae)
Authors: Faucheux Michel J.
Published: March 2009

We have examined antennae of both sexes of Tineola bisselliella to make an inventory of the antennal sensilla. We distinguished two types of sensilla trichodea, two types of sensilla basiconica, and sensilla auricillica, chaetica, coeloconica, styloconica, and campaniformia, Böhm's bristles, and squamiform structures. The same types of sensilla are present in both sexes. Numbers of sensilla chaetica, styloconica, and coeloconica and Böhm's bristles do not differ between the sexes. Significant differences in number and distribution of sensilla trichodea, basiconica, and auricillica were found between females and males over the whole length of the antenna.
Social organization of snowshoe hares
Authors: Graf R. P.
Published: March 2009

Snowshoe hares, Lepus americanus, showed various stereotyped agonistic behaviours in both penned and wild populations. Male hares were involved more frequently and in more intense interactions than females. Hares displayed dominance hierarchies in pens, at feeding stations in the wild, and in a completely natural situation. Males were most dominant in the winter, but females were most dominant during the summer breeding season. It is suggested that the switch in dominance occurred because of changes in the approach behaviour of males towards females. In view of the aggression exhibited by this species, further investigation of behavioural population regulation hypotheses is warranted.
Year-round presence of high levels of plasma antifreeze peptides in a temperate fish, ocean pout (Macrozoarces americanus)
Authors: Fletcher Garth L. , Hew Choy L. , Li Xiaomao , Haya Katsuji , Kao Ming H.
Published: March 2009

The annual cycle of plasma antifreeze activity and Na+ and Cl− concentrations were measured in Newfoundland and New Brunswick ocean pout (Macrozoarces americanus) maintained in the laboratory under Newfoundland conditions of water temperature and photoperiod. The Na+ and Cl− concentrations and antifreeze activity showed distinct seasonal cycles in both groups of fish, with the highest values occurring during the winter. Relatively high concentrations of antifreeze peptides were present in the Newfoundland ocean pout at all times of the year. Antifreeze peptides were also present in the New Brunswick fish throughout the year; however, the concentrations found were approximately one-tenth of those observed in Newfoundland fish. A comparison of the antifreeze peptides from summer and winter samples from Newfoundland ocean pout and winter samples from New Brunswick ocean pout using high performance liquid chromatography revealed essentially identical elution profiles.
Northern corn rootworm beetle densities near a red-winged blackbird roost
Authors: Bollinger Eric K. , Caslick James W.
Published: March 2009

Population estimates of northern corn rootworm beetles (Diabrotica longicornis (Say), Chrysomelidae; Coleoptera) increased linearly away from a red-winged blackbird (Agelaius phoeniceus (L.), Emberizidae; Passeriformes) roost located at Montezuma National Wildlife Refuge, Cayuga County, New York, U.S.A. Red-winged blackbirds foraging in cornfields near this roost commonly consumed rootworm beetles, indicating that this predation could have been responsible for the lower rootworm beetle populations in this area. However, even if the reduced beetle numbers near the red-winged blackbird roost were the result of predation by this bird, this benefit compensated for only approximately 4% of the damage the birds inflicted to standing corn.
Utilization of dry matter and elements by larvae of the sawflies Neodiprion sertifer (Geoff.) and Diprion similis (Hartig) feeding on Scots pine needles
Authors: Slansky Jr. F. , Fogal W. H.
Published: March 2009

Consumption and proportions of dry matter and various elements utilized by late-instar larvae of Diprion similis (Hartig) and Neodiprion sertifer (Geoff.) feeding on previous years' needles of Scots pine (Pinus sylvestris L.) were determined gravimetrically and by means of cellulose as an indigestible marker substance. The only discrepancy between the two methods was for phosphorus intake by N. sertifer females. Female larvae of D. similis utilized larger proportions of dry matter, nitrogen, and potassium and less phosphorous than female larvae of N. sertifer; both species utilized similar proportions of calcium and magnesium. Combined male–female groups of N. sertifer larvae utilized larger proportions of dry matter, potassium, and magnesium compared with female larvae. The proportions utilized were ranked as follows: nitrogen (50–59%), phosphorous (22–39%), magnesium (15–29%), calcium (9–15%), and potassium (6–17%). Nonpositive sodium budgets precluded calculation of utilization of this element. The proportions of dry matter utilized by these sawflies are similar to those for 10 species of foliage-consuming Hymenoptera and fall toward the lower end of the range of values for phytophagous insects. Nitrogen utilization figures for these sawflies fall within the range of values reported for insects that consume tree foliage.
Fine structure of the phasmid of second-stage juveniles of Heterodera schachtii (Tylenchida: Nematoda)
Authors: Baldwin James G.
Published: March 2009

The phasmid of infective second-stage juveniles of Heterodera schachtii consists of an external pore, cuticle-lined duct, socket cell, sheath cell, and single dendrite receptor. Specimens vary in detail and two discrete types, designated A and B, can be distinguished, with A being larger and relatively more complex. In both types of phasmids the socket cell is roughly cup shaped, envelops the duct, and partially encloses and forms junctional complexes with the sheath cell. The sheath cell fills the cup of the socket cell and occurs near the proximal end of the duct. In the A phasmid the sheath cell is deeply invaginated, forming a receptor cavity which is continuous with a maze of extracellular channels penetrating the cell; secretions accumulate in the channels and receptor cavity. Conversely, the sheath cell of the B phasmid lacks a receptor cavity and is nonsecretory. The sheath cell of both types of phasmid encloses and forms junctional complexes with a single dentritic process. In the A phasmid the process terminates within the receptor cavity whereas in the B type the tip is embedded within the sheath cell. A typical basal body or rootlets were not observed, although a ciliary region with a circle of eight doublets surrounding three or four singlets occurs slightly proximal to the terminus. Knowledge of phasmid structure of H. schachtii provides a basis for study of phasmid development and function in a plant parasite; it also contributes to understanding comparative morphology for phylogenetic analysis of Heteroderidae.
Reproductive output and population biology of Cystidicola stigmatura (Leidy) (Nematoda) in Arctic char, Salvelinus alpinus (L.) (Salmonidae)
Authors: Black Geoff A.
Published: March 2009

The reproductive output and population biology of the swim bladder nematode, Cystidicola stigmatura, were examined in Salvelinus alpinus in Gavia Lake, Northwest Territories, Canada. The size and number of gravid female nematodes increased with fish age, supporting the suggestion that worms are long-lived and grow throughout their lives. Fecundity was linearly related to the length of gravid female nematodes. Reproductive output of parasites in individual fish (estimated by the number of free eggs in swim bladders) was overdispersed in the host population and was concentrated in the oldest age-classes of char. The latter feature makes populations of the parasite susceptible to exploitation of their fish hosts. It was estimated that in Gavia Lake exploitation of larger fish decreased nematode egg production by about one half over a 7-year period. Decline of fish stocks has probably resulted in extinction of populations of C. stigmatura in at least nine lakes in southern Ontario and northern New York State.
Thermal sensitivity of contractile function in chain pickerel, Esox niger
Authors: Sidell Bruce D. , Johnston Ian A.
Published: March 2009

Maximum catalytic activity and thermal sensitivity of Mg2+–Ca2+ activated myofibrillar ATPase from either red or white muscle tissue of chain pickerel is unaffected by 4–6 weeks acclimation to temperatures of 5 or 25 °C. Arrhenius plots of myofibrillar ATPase activity from red muscle are linear over the entire range of assay temperatures (2–32 °C; Q10 = 3.3). Similar plots of white muscle ATPase activity show a pronounced discontinuity at approximately 10 °C and a much greater thermal sensitivity below this temperature (Q10 = 11.2) than above it (Q10 = 2.2). Thermal dependence of myofibrillar ATPase activity from white muscle does not accurately predict the effect of temperature upon contraction velocities of isolated white muscle fibers. Contraction velocity of single chemically skinned white muscle fibers was sevenfold less temperature sensitive than ATPase activity below the 10 °C transition and 1.6-fold less temperature sensitive above this temperature (Q10 (0–27 °C) = 1.6). Maximum Ca2+-activated tension development was particularly temperature independent (Q10 = 1.2), ranging from 14 ± 1.6 N/cm2 at 5 °C to 20.9 ± 2.1 N/cm2 at 25 °C. Power output chain pickerel muscle, a product of these two parameters (force × velocity), should therefore show a relatively low thermal dependence (Q10 < 2) over the normal range of habitat temperatures.
Gastric emptying time and assimilation efficiency in Atlantic mackerel (Scomber scombrus)
Authors: Lambert Timothy C.
Published: March 2009

Adult mackerel (Scomber scombrus) acclimated at 17.5 °C cleared their stomachs of silversides (Menidia menidia) at a constant rate. The time to complete emptying was approximately 28 h and did not seem to be affected by either ration size or body weight. Assimilation efficiency (calories) was 95%. Considerable ash was assimilated, probably in response to depletion of calcium reserves, after the shedding of spawning products.
Monitoring respiration and activity in the spider Geolycosa domifex (Hancock) using time-lapse television and CO2 gas analysis
Authors: Culik B. M. , McQueen D. J.
Published: March 2009

The activities of individual burrowing wolf spiders were continuously recorded with time-lapse television and respiration rates were simultaneously recorded. Five categories of activity and rest were differentiated and it was found that resting rates on the surface of the burrow and in the burrow were indistinguishable and similar to measures recorded in other studies. On average, in-burrow activity required 55% more energy than resting, surface activity required 220% more energy, and vertical activity (moving up the burrow) required 1780% more energy than resting. These data were analyzed with respect to the periodicity of activity patterns observed in the field and it was found that respiration rates that relate to periods of field activity are 40% higher than rates recorded for spiders assumed to be at rest.
Origin and distribution of the Chironomidae (Diptera) from the Saskatchewan River, Saskatchewan, Canada
Authors: Mason P. G. , Lehmkuhl D. M.
Published: March 2009

Approximately one third of the named Saskatchewan River chironomid species have Holarctic distributions, the remaining species are strictly Nearctic. Only 6 of the 143 species so far recorded from the Arctic are present in the Saskatchewan River. In contrast, 69 of the 76 named Saskatchewan River species are also found in eastern North America. Of the remaining seven, Cyphomella gibbera Saether, Chernovskiia amphitrite (Townes), Parakiefferiella (s.str.) torulata Saether, and the Holarctic Cricotopus (Isocladius) intersectus (Staeger) have previously been recorded only from Manitoba in the Nearctic. Synorthocladius semivirens Kieffer, a Holarctic species, is known only from northern and western Canada in North America, and Cryptotendipes darbyi Sublette and Stictochironomus quagga (Townes) have western distributions. Analysis of distribution records from recent subgeneric revisions of Orthocladius (Orthocladius) and Polypedilum (Polypedilum) suggest that the majority of Saskatchewan River species originated from southern refugia. This conclusion is supported by studies of other aquatic animals in western Canada, which also appear to be derived from southern refugia.
Rhigonematid (Nematoda) parasites of Archispirostreptus tumuliporus (Spirostreptida; Diplopoda) in Malawi
Authors: Adamson Martin L. , Anderson Nancy H. B.
Published: March 2009

Two new species, including a new genus of rhigonematid nematode, are described from Archispirostreptus tumuliporus (Spirostreptida; Diplopoda) from Malawi. Brumptaemilius justini n.sp. resembles Brumptaemilius sclerophorus, the type species, and Brumptaemilius oschei in the form of the area rugosa in the male. It differs from male B. sclerophorus in having a caudal appendage which is longer and supports the last pair of caudal papillae; this pair is anterior to the caudal appendage in B. sclerophorus. Male B. justini differ from those of B. oschei in having a shorter caudal appendage, distinctly set off from the rest of the body, and in possessing a field of tiny bosses on either side in the anal region. Waerebekeia n.gen., with type species Waerebekeia simoni n.sp., resembles Brumptaemilius since males have a urceolate buccal cavity with three prominent pennate cuticular projections and three trifid teeth at its base. The genera are distinguished by the shape of the oral opening in the male (laterally elongate in Waerebekeia; subtriangular in Brumptaemilius), by the absence of an area rugosa and by the more dorsal position of the third papilla pair in male Waerebekeia.
The relationship between the size of some salmonid fishes and the intensity of their acanthocephalan infections
Authors: Amin Omar M.
Published: March 2009

Of the complex factors affecting the abundance of acanthocephalan infections in their definitive fish hosts, those related to fish age are considered. In Lake Michigan, the abundance of some 8000 worms, mostly Echinorhynchus salmonis (Müller, 1784), was independent of the age (weight) of coho salmon, Oncorhynchus kisutch (Walbaum), chinook salmon, Oncorhynchus tshawytscha (Walbaum), and lake trout, Salvelinus namaycush (Walbaum), using linear regression analysis. Other E. salmonis infection patterns include steady increase in abundance with host age and a maximal increase in midage. A decrease in abundance with host age was demonstrated in other acanthocephalan species. The above patterns were primarily related to host feeding behavior as well as spatial and seasonal distribution of invertebrate and vertebrate larval hosts. A progressive increase in the abundance of Echinorhynchus through midage or through life is associated with a stable intake of an invertebrate diet, including the infected intermediate host, in larger volumes by older fish. Loss of the latter two patterns is affected by destabilizing the above trend through total or partial replacement of the invertebrate diet with a piscivorous one.
Erpobdella montezuma (Hirudinoidea: Erpobdellidae), a new species of freshwater leech from North America
Authors: Davies Ronald W. , Singhal R. N. , Blinn D. W.
Published: March 2009

Morphological and taxonomic descriptions are given of an erpobdellid found to be a new species of Erpobdella Blainville, 1818 collected from Montezuma Well, Arizona, U.S.A. Mature individuals of Erpobdella montezuma sp. nov. do not exceed 71 mm total length, have three pairs of eyes with the second and third pairs smaller, and have dorsal paramedial stripes that are densely pigmented. On the dorsum and venter of each annulus lie 14–18 small white-tipped papillae containing the sensory organs. Six pairs of bunches of large testicular follicles (three to five in a bunch) are present. The morphological and anatomical variations between E. punctata and E. montezuma are described.
A new Paraleuctra (Plecoptera; Leuctridae) from the Cascade and Coast ranges
Authors: Harper P. P. , Wildman R. C.
Published: March 2009

Paraleuctra andersoni n. sp. is described from the Western Cascades of Oregon and the Coast Range of California. It is related to Paraleuctra purcellana (Neave) from the Rocky Mountains. The two species form an isolated group within the genus Paraleuctra.
Duration of strike-induced chemosensory searching in cottonmouths (Agkistrodon piscivorus) and a test of the hypothesis that striking prey creates a specific search image
Authors: Chiszar David , Radcliffe Charles W. , Overstreet Roy , Poole Thomas , Byers Thomas
Published: March 2009

Cottonmouths (Agkistrodon piscivorus) emitted significantly more tongue flicks after striking rodent prey than after seeing, smelling, and (or) detecting thermal cues from rodent prey. This strike-induced chemosensory searching (SICS) persisted for about 70 min. Prey-derived molecules acquired during the strike would not be expected to remain available to the vomeronasal organs for more than 10 min. Hence, the duration of SICS suggests (i) that a central nervous system (CNS) representation of prey is formed as a consequence of the strike and (ii) that this representation or search image has memorylike properties and remains available to guide searching behavior for a longer time than would be expected on the basis of poststrike residuation of chemically induced afference in the vomeronasal system. In experiment II, cottonmouths struck either rodent or fish prey (which were removed immediately after the strike) and 10 min later the snakes were allowed to ingest either a fish or a mouse. When the prey offered for ingestion was the same type as the prey struck, snakes grasped their prey quickly, whereas, in all other conditions, only a few snakes responded quickly and others did so after much longer latencies. It is proposed that CNS representations of fish and mice have some nonoverlapping features and that a disposition to grasp the type of prey that was initially struck endures until these prey-specific features have degraded (presumably through the ordinary process of forgetting).
The influence of exercise–handling stress on blood lactate, acid–base, and plasma glucose status of northern pike (Esox lucius L.)
Authors: Schwalme K. , Mackay W. C.
Published: March 2009

Changes in blood lactate, pH, Pco2, and plasma [Formula: see text] and glucose were measured during recovery from exercise–handling stress in chronically cannulated northern pike (Esox lucius L.). Exercise was induced by lifting pike out of water (three 30-s periods of emersion alternated with 30-s periods of water submersion), while they were inside tubular plastic chambers. Large depressions in blood pH and plasma [Formula: see text] occurred within minutes after exercise. Initially, the acidosis was of mixed respiratory (elevated Pco2) and metabolic (H+ release from the muscle) origin. Although the respiratory acidosis was corrected in 2 h, 8 h was required to return blood pH to preexercise levels. A large accumulation of lactate anion in the blood occurred after exercise, the increase by 2 h (12.8 mmol L−1), being approximately equal to the metabolic acid load. These results conflict with previous reports on muskellunge (Esox masquinongy M.), in which blood lactate elevation following exercise was small (2.5 mmol L−1) and greatly exceeded by the metabolic H+ load (7.0 mmol L−1). By 2 h after exercise the plasma glucose level of pike had increased by 8.8 mmol L−1 and the return to preexercise levels was almost complete by 12 h. Intraarterial infusion of a large sodium lactate load elevated plasma glucose level by only 1.7 mmol L−1, indicating that postexercise hyperglycemia in pike is a response to stress and not simply a consequence of lactate removal by conversion into glucose.
Food-searching behaviour of the common merganser (Mergus merganser) I: Functional responses to prey and predator density
Authors: Wood C. C. , Hand C. M.
Published: March 2009

The hunting performance of the common merganser (Mergus merganser) was evaluated in relation to prey density and merganser flock size by stocking three enclosed sections of a natural stream with known densities of juvenile coho salmon (Oncorhynchus kisutch). Two size classes of coho were stocked: smolt averaging 43 g at densities of 0.02–0.65/m2, fry averaging 2 g at 0.08–1.6/m2 and various mixtures of smolt and fry at a combined density of 0.65/m2. The stream enclosures differed in the amount of cover available to fish. Mergansers were less successful at capturing coho smolt or fry in the enclosures wth cover from undercut banks. Smolt exposed to mergansers earlier that day were less vulnerable than smolt with no previous exposure. The feeding success of individual mergansers was not significantly affected by flock size for flocks of 25 birds or less. A smoothly asymptotic functional response (type II) was observed under all experimental conditions. Coho smolt were selected over coho fry. It is concluded that a merganser's average daily food requirement (ca. 400 g) can be satisfied at smolt densities of 0.02–0.30/m2 depending on the availability of cover for smolt and their previous exposure to mergansers.
Seasonal patterns and sexual differences in the feeding ecology of arctic ground squirrels (Spermophilus parryii plesius)
Authors: McLean Ian G.
Published: March 2009

Arctic ground squirrels (Spermophilus parryii plesius) were studied in southwestern Yukon during the summers of 1977, 1978, and 1979. Samples of feces were collected from every adult captured every 2 weeks in 1978. Legumes were predominant in the diet until the fall, when squirrels switched to Artemisia. Females switched to Artemisia 1 month earlier than males, which correlates with the females' earlier entry into hibernation. Low abundance of legumes in areas in which squirrels preferred to feed indicated that squirrels fed selectively, although proximity of burrows also influenced selection of feeding sites.