bluuebunny/crossref_metadata_2025 huggingface dataset:
Multisyllabic nonwords: More than a string of syllables
Authors: Archibald Lisa M. D. , Gathercole Susan E. , Joanisse Marc F.
Published: March 2009

Nonword repetition is closely associated with the learning of the phonological form of novel words. Several factors influence nonword repetition performance such as short-term memory, phonotactic probability, lexical knowledge, and prosodic factors. The present study examined the influence of list duration, coarticulation, and prosody on nonword repetition by comparing naturally articulated multisyllabic nonwords to multisyllabic nonwords formed by concatenating syllables produced in isolation and serial lists (experiment 1), to multisyllabic forms that incorporated either valid or invalid coarticulatory information (experiment 2), and to multisyllabic forms either with or without common English within-word stress patterns (experiment 3). Results revealed superior recall for naturally articulated nonwords compared to lists of matched duration or sequences with invalid coarticulatory cues. Within-word stress patterns also conveyed a repetition advantage. The findings clearly establish that the coarticulatory and prosodic cues of naturally articulated multisyllabic forms support retention.
Array element localization using ship noise
Authors: Morley Michael G. , Dosso Stan E. , Chapman N. Ross
Published: March 2009

This paper describes a method of estimating hydrophone positions in a receiver array using the noise from a passing ship. Relative arrival times of the ship-noise signal between pairs of hydrophones are obtained from several time windows of data (corresponding to different ship locations) by cross-correlating the band-pass filtered time series. The relative arrival times are used as data in an array element localization inversion to estimate both the hydrophone and ship locations based on iterated linearization of the acoustic ray equations. The inversion applies the method of regularization to include prior information such as approximate location estimates and uncertainties for the source and receivers and the expectation that the array shape and∕or source tracks are smooth functions of position. Linearized and nonlinear (Monte Carlo) estimates of the position errors are in good agreement and indicate a high degree of confidence in the receiver positions (relative uncertainties of approximately 0.2m in the horizontal and 0.05–0.1m in the vertical). The ability to improve upon the initial source position estimates depends on the geometry of the problem, as investigated with simulations.
Normal incidence sound transmission loss evaluation by upstream surface impedance measurements
Authors: Panneton Raymond
Published: March 2009

A method is developed to obtain the normal incidence sound transmission loss of noise control elements used in piping systems from upstream surface impedance measurements only. The noise control element may be a small material specimen in an impedance tube, a sealing part in an automotive hollow body network, an expansion chamber, a resonator, or a muffler. The developments are based on a transfer matrix (four-pole) representation of the noise control element and on the assumption that only plane waves propagate upstream and downstream the element. No assumptions are made on its boundary conditions, dimensions, shape, and material properties (i.e., the element may be symmetrical or not along its thickness, homogeneous or not, isotropic or not). One-load and two-load procedures are also proposed to identify the transfer matrix coefficients needed to obtain the true transmission loss of the tested element. The method can be used with a classical two-microphone impedance tube setup (i.e., no additional downstream tube and downstream acoustical measurements). The method is tested on three different noise control elements: two impedance tube multilayered specimens and one expansion chamber. The results found using the developed method are validated using numerical simulations.
Highly Accurate Antibody Assays for Early and Rapid Detection of Tuberculosis in African and Asian Elephants
Authors: Greenwald Rena , Lyashchenko Olena , Esfandiari Javan , Miller Michele , Mikota Susan , Olsen John H. , Ball Ray , Dumonceaux Genevieve , Schmitt Dennis , Moller Torsten , Payeur Janet B. , Harris Beth , Sofranko Denise , Waters W. Ray , Lyashchenko Konstantin P.
Published: March 2009

Tuberculosis (TB) in elephants is a reemerging zoonotic disease caused primarily byMycobacterium tuberculosis. Current methods for screening and diagnosis rely on trunk wash culture, which has serious limitations due to low test sensitivity, slow turnaround time, and variable sample quality. Innovative and more efficient diagnostic tools are urgently needed. We describe three novel serologic techniques, the ElephantTB Stat-Pak kit, multiantigen print immunoassay, and dual-path platform VetTB test, for rapid antibody detection in elephants. The study was performed with serum samples from 236 captive African and Asian elephants from 53 different locations in the United States and Europe. The elephants were divided into three groups based on disease status and history of exposure: (i) 26 animals with culture-confirmed TB due toM. tuberculosisorMycobacterium bovis, (ii) 63 exposed elephants from known-infected herds that had never produced a culture-positive result from trunk wash samples, and (iii) 147 elephants without clinical symptoms suggestive of TB, with consistently negative trunk wash culture results, and with no history of potential exposure to TB in the past 5 years. Elephants with culture-confirmed TB and a proportion of exposed but trunk wash culture-negative elephants produced robust antibody responses to multiple antigens ofM. tuberculosis, with seroconversions detectable years before TB-positive cultures were obtained from trunk wash specimens. ESAT-6 and CFP10 proteins were immunodominant antigens recognized by elephant antibodies during disease. The serologic assays demonstrated 100% sensitivity and 95 to 100% specificity. Rapid and accurate antibody tests to identify infected elephants will likely allow earlier and more efficient treatment, thus limiting transmission of infection to other susceptible animals and to humans.
Interlaboratory Reproducibility of a Single-Locus Sequence-Based Method for Strain Typing of
Aspergillus fumigatus
Authors: Hurst S. F. , Kidd S. E. , Morrissey C. O. , Snelders E. , Melchers W. J. G. , Castelli M. V. , Mellado E. , Simmon K. , Petti C. A. , Richardson S. , Zhang S. , Romanelli A. M. , Wickes B. L. , de Valk H. A. , Klaassen C. H. W. , Balajee S. Arunmozhi
Published: March 2009

Seven international laboratories tested the recently proposed single-locus typing strategy for
Aspergillus fumigatus
subtyping for interlaboratory reproducibility. Comparative sequence analyses of portions of the locus AFUA_3G08990, encoding a putative cell surface protein (denoted CSP), was performed with a panel of
Aspergillus
isolates. Each laboratory followed very different protocols for extraction of DNA, PCR, and sequencing. Results revealed that the CSP typing method was a reproducible and portable strain typing method.
The comparative ecology and evidence for resource partitioning in two pholidid fishes (Pisces: Pholididae) from southern British Columbia eelgrass beds
Authors: Hughes Grant W.
Published: March 2009

A comparative analysis of the ecology of sympatrically occurring Pholis laeta and Pholis ornata was conducted in Saanich Inlet, British Columbia. Summer microhabitat use of eelgrass bed depths, intertidal habitat use, prey type, and characteristic location of prey taken differed in fish older than 1 year and may have facilitated the coexistence of these morphologically similar species. Prey sizes and activity patterns were similar between species. Winter segregation of the species during the breeding season may have reduced the possibility of hybridization. Competition for breeding habitats and differences in trophic apparatus may partly explain the observed patterns of resource use.
Effects of temperature and season on the position holding performance of juvenile Atlantic salmon (Salmo salar)
Authors: Rimmer D. M. , Saunders R. L. , Paim U.
Published: March 2009

The ability of wild and hatchery yearling Atlantic salmon (Salmo salar) to hold a position against water currents was tested in relation to water temperature and season. This species would not swim, but held positions on the bottom of the test apparatus. Their performance was, therefore, rated on the basis of critical holding velocity instead of critical swimming velocity, often used for other species. Qualitatively, the relationships of critical holding velocity with both temperature and season were similar for wild and hatchery fish. However, wild fish were consistently more able to hold positions against water currents so that the mean water velocities at which they were unable to stem water currents were 25–84% greater than those for hatchery fish. In the winter, the mean water velocities against which both wild and hatchery fish could no longer hold a position were 21.9–50.0% lower than in the summer. Seasonal changes in performance generally increased or decreased with water temperature except in winter when performance declined while water temperature was almost constant. Performance was high and almost unchanging for temperatures above 8 °C, but fell sharply below this temperature. We suggest that the sharp decrease in performance at 8 °C explains the previous observation that this species suddenly moves into the stream bed when temperature falls during the autumn.
Acidity and associated water chemistry of amphibian habitats in Nova Scotia
Authors: Dale J. M. , Freedman B. , Kerekes J.
Published: March 2009

One hundred and fifty-nine field sites consisting of ditches, bogs, marshes, ponds, and lakes in south and central Nova Scotia were surveyed for the presence of the adults, eggs, or larvae of 11 amphibian species. Water samples were analyzed for pH, alkalinity, color, conductivity, Na, K, Mg, Ca, SO4, and Cl. Discriminant function analysis revealed that none of these variables predicted a species' presence. Two three-species groups were found to be significantly associated among themselves, but mutually exclusive of each other. The two groups were (i) Ambystoma maculatum, Hyla crucifer, and Rana sylvatica and (ii) Rana clamitans, Rana catesbeiana, and Rana palustris. Rana sylvatica and A. maculatum were observed breeding successfully in an acidic bog (mean pH 4.1). Rana clamitans adults and larvae were located in the field at pHs as low as 3.5 and 3.9, respectively. Field transplant studies, using eggs of A. maculatum and R. sylvatica (at pH 5.7 and 4.1) and Bufo americanus (at pH 6.3 and 4.1), revealed that R. sylvatica was least sensitive to acidity. There is considerable variation in acid tolerance among the various species of Nova Scotia amphibians. Nevertheless, successful breeding by some species is occurring at very low pHs.
Breeding by Peromyscus maniculatus over an elevational gradient
Authors: Millar John S. , Innes Duncan G. L.
Published: March 2009

Autopsy data Peromyscus maniculatus borealis were examined to determine differences in seasonal breeding, litter size, breeding success, and growth rates over an approximately 1000 m elevational gradient in the Kananaskis Valley, Alta. All overwintered females bred during the summer, although those at low elevations [Formula: see text] gave birth over a longer period of time (14 weeks) than those at intermediate ([Formula: see text]; 12 weeks) and high ([Formula: see text]; 6 weeks) elevations. Average dates of birth were later (by 0.039 days/m) at high elevations than at low elevations. Postpartum breeding appeared more frequent at high elevations than at low elevations. Breeding by young of the year females was rare (three recorded in 6 years), although many young of the year males born early in the breeding season exhibited some gonadal development. Adult weight, litter size, growth rates, and breeding success did not differ with elevation. Temporal differences in breeding appear to ensure that births occur and young are raised under similar environmental conditions at all elevations.
Revision of the congrogadid Haliophis (Pisces: Perciformes), with the description of a new species from Indonesia, and comments on the endemic fish fauna of the northern Red Sea
Authors: Winterbottom Richard
Published: March 2009

The genus Haliophis presently consists of two species, H. guttatus (Forsskål, 1755), and a new species from Bali, Indonesia. Descriptions, diagnoses, and a key are provided for these taxa. A step cline occurs in H. guttatus, which ranges from 15° S to 30° N in the western Indian Ocean and Red Sea. Populations from 27 to 30°N differ most from those in the southern Red Sea and Gulf of Aden, but less so from those south of the equator. The step occurs between 20 and 27° N, an area from which no specimens were located, and is congruent with the distributions of at least four other taxa of fishes as well as with several populational differences in other species. This indicates that these distributional patterns may form part of a generalized track, rather than being the result of ecophenotypic effects. In the Red Sea – northern Indian Ocean region, the most common distribution of endemic fishes includes both the Red Sea and the Gulf of Aden. This pattern was not apparent in populations of H. guttatus.
Meristic and morphometric variation in pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound
Authors: Beacham Terry D.
Published: March 2009

Variation in the number of gill rakers and four morphometric characters was examined for 4 stocks from the even-year brood line and 20 stocks from the odd-year brood line of pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound. Significant differences in gill-raker frequencies were observed among stocks within each brood line, but differences were greater between the brood lines than within each brood line. Sizes of the morphometric characters standardized to a body length of 419 mm were also variable among stocks within a brood line, but stocks spawning in rivers in the same region in alternate years were more similar morphometrically than to those spawning in different regions. It is suggested that patterns of meristic and morphometric variability are reflective of genetic differences, with meristic variability illustrating the genetic differences between the brood lines, and morphometric variability reflecting adaptation to local water velocity conditions in the streams the stocks return to during spawning.
Glugea pimephales Fantham, Porter and Richardson, 1941, n. comb. (Microsporidia, Glugeidae) in the fathead minnow, Pimephales promelas
Authors: Morrison Carol , Hoffman G. L. , Sprague Victor
Published: March 2009

A microsporidan parasite, fitting the description of Nosema pimephales Fantham, Porter and Richardson, 1941, was found in fry of the fathead minnow, Pimephales promelas Rafinesque, from the Wray Fish Hatchery near Fort Morgan, Colorado. More detailed studies proved it to be a typical species of Glugea Thélohan, 1891, to which genus it was transferred. Presence of a delicate sporophorous vesicle, like that recently demonstrated in the type species, was observed. A sequence of three distinct kinds of divisions within that membrane, beginning with the plasmodium and ending with sporoblasts, was recognized. These were plasmotomy, multiple fission, and binary fission. The first two kinds, under the one name or the other, have been treated as one process in previous studies on species of Glugea. Results of this, a well as of recent studies, compel us to reconsider our concepts of "sporont" and "sporogony."
Phylogenetic analysis of the Digenea (Platyhelminthes: Cercomeria) with comments on their adaptive radiation
Authors: Brooks Daniel R. , O'Grady Richard T. , Glen David R.
Published: March 2009

Phylogenetic analysis of 63 digenean family groups, based on 113 adult characters and 90 larval characters, produced a phylogenetic tree comprising nine orders. Adult characters alone resolved 76% of the phylogenetic tree, whereas larval characters alone resolved 74%. There was no disagreement in phylogenetic inferences drawn from only larval or only adult characters, and yet the larval forms of digeneans do not seem to be recapitulations of ancestral adult forms. The consistency index for the tree is 74%, indicating a low degree of parallel evolution in digenean morphology. Diversification in six sets of ecological characteristics combined resolves 26% of the phylogenetic tree. The combination of (i) larval and adult congruence in the absence of recapitulation, (ii) low levels of parallel evolution in morphology, and (iii) ecological diversification lagging far behind morphological change discounts traditional notions of adaptive radiations. Digeneans have experienced great morphological diversification constrained by their developmental programs and history, and have maintained their functional intergrity with few changes caused by extrinsic, "adaptive," forces.
Differences in amino acid requirements between two biotypes of the pea aphid, Acyrthosiphon pisum
Authors: Srivastava P. N. , Gao Y. , Levesque J. , Auclair J. L.
Published: March 2009

Amino acid requirements of two biotypes (C and J) of the pea aphid, Acyrthosiphon pisum (Harris), were studied by deleting single amino acids from a chemically defined liquid diet. Amino acids found to be essential for growth and (or) reproduction of biotype C were arginine, histidine, leucine, lysine, methionine, threonine, and tryptophan, and for biotype J, histidine, methionine, phenylalanine, threonine, and valine. Two generations were needed on deficient diets to demonstrate the essentiality of some of the amino acids. This appears to be a rare example of two insect populations within one species differing in their amino acid requirements. It is suggested that intracellular symbiotes play a major role in supplying the aphids with missing amino acids.
Protein and lipid absorption in the intestinal mucosa of adult lampreys (Petromyzon marinus L.) following induced feeding
Authors: Langille Robert M. , Youson John H.
Published: March 2009

Young adult lampreys (Petromyzon marinus) were force-fed either on polyunsaturated lipid or on a protein tracer following a period of starvation to follow the absorption and intracellular transport of these substances in the intestine. Type A and B absorptive cells of the diverticulum, anterior intestine, and transition zone are the principal cells of lipid absorption and transport, whereas protein absorption is confined to caveolated cells of the posterior intestine and hindgut. Lipoprotein, corresponding to very low density lipoprotein (VLDL), becomes localized in smooth and rough endoplasmic reticulum, smooth tubules, and in the Golgi saccules and vesicles, while lipid droplets are localized in the cytoplasmic matrix. The localization of VLDL in the lateral intercellular space and extracellular space, including the submucosal connective tissue and the lumina of the capillaries, are believed to be an expression of the manner in which lipid is absorbed and transported in the anterior segments of the lamprey intestine. Protein absorption in caveolated cells follows the pattern noted in cells of similar function in other fishes and involves pinocytotic vesicles, a tubulovesicular network, heterophagic vacuoles, and likely a lysosomal system for degradation and condensation of the endocytosed material. The presence of regions specialized for lipid and protein absorption in the intestine of adult lampreys is comparable to the situation in many other fishes.
Stimulation de la synthèse de vitellogénine chez le mâle de Rhodnius prolixus (Stål) par un mimétique de l'hormone juvénile
Authors: Chalaye D. , Lauverjat S.
Published: March 2009

The effect of the juvenile hormone analogue methoprene on the stimulation of vitellogenin synthesis was examined in male Rhodnius prolixus using rocket immunoelectrophoresis. The concentration of haemolymphatic vitellogenin was increased in a dose-dependent fashion by applying methoprene topically in quantities ranging from 2 to 20 μg. Repeated treatment with 10 to 20 μg amplified the response. Cytological modifications of the fat body resulted from the treatment. Sexual dimorphism of the fat body disappeared after treatment with 5 μg methoprene. A single dose of 10 μg resulted in the specialization of adipocytes for protein synthesis, a characteristic found in the adipocytes of vitellogenic females.
Effects of hypoxic adaptation on myocardial performance and metabolism of Zoarces viviparous
Authors: Driedzic William R. , Gesser Hans , Johansen Kjell
Published: March 2009

Zoarces viviparous were maintained in either normoxic or hypoxic ([Formula: see text], 4–4.7 kPa) water for 4–6 weeks. The hypothesis that adaptation to hypoxia results in an increase in the potential for anaerobic energy production in heart was tested. There was no difference in the activities of key enzymes of energy metabolism or in the content of myoglobin between the hearts from control or experimental fish. However, ventricular strips from animals adapted to hypoxic conditions were better able to sustain tension development than hearts from control animals during anoxia in the presence of high levels of external Ca2+. A combination of high Ca2+ and glucose was particularly effective in improving performance. The data suggest that hypoxic adaptation leads to an enhancement of Ca2+-activated carbohydrate mobilization but that the enzyme complement required to process the additional glycolytic flux is already in place.
Sexual and asexual reproduction in a natural population of Hydra pseudoligactis
Authors: Bell Graham , Wolfe Lorne M.
Published: March 2009

Populations of Hydra pseudoligactis were censussed during 1980–1981 in a lake and a small pond in southern Québec. Both natural and artificial substrates (glass slides) were used. Population density rose during the early part of the season to a maximum in June–July, after which a decline in the rate of asexual budding drove density down. The decline in budding rate lagged about 2 weeks behind the increase in density. High local population density on the glass slides reduced rates of budding and caused dispersal from crowded slides. Sexual individuals appeared in the middle of the growing season, near the time of maximal density, when rates of asexual budding had begun to fall. Moreover, sexual individuals were more frequent in the site where and in the year when budding rates were lower; 66% of the variance in the frequency of sexual individuals between dates in the pond was explained by variance in the number of buds borne by asexual individuals. These results are held to be consistent with the interpretation of sexuality as a device to reduce competition between offspring in a spatially heterogeneous environment.
Le genre Mesocyclops (Crustacé, Copépode) en Amérique du Nord
Authors: Dussart B. H.
Published: March 2009

A new description of Mesocyclops edax and the first description of Mesocyclops americanus n. sp. (= M. leuckarti auctorum of North America) are given.
Larval development and metamorphosis of Sabellaria cementarium Moore, 1906 (Polychaeta: Sabellariidae)
Authors: Smith Peter R. , Chia Fu-Shiang
Published: March 2009

The development of the polychaete Sabellaria cementarium Moore, 1906 proceeds at 10–14 °C, as follows: 23 h, early trochophore with prototroch and apical tuft; 65 h, 1 pair of provisional setae; 3.5 days, feeding trochophore; 18 days, metatrochophore; 4 weeks, metatrochophore with tentacle buds; 5–6 weeks, nectochaeta competent to metamorphose; 6–8 weeks, settlement and metamorphosis. Larval behavior is described. Tube sand of adult sabellariids (S. cementarium, Phragmatopoma lapidosa, ldanthrysus ornamentatus) and beach sand induced metamorphosis. Larvae exhibit a low degree of substrate specificity in their settlement, but sand is essential. Metamorphosis involves a loss of provisional setae, anterior rotation of tentacles and opercular cirri, and reduction of episphere. Following these changes, the juvenile secretes a mucoid tube to which sand grains are attached. Metamorphosis is considered complete when the caudal appendage has formed; this occurs 7–10 days postsettlement. Juveniles were kept in the laboratory for 38 days. During this time, they develop three pairs of tentacles, lose all larval pigment, and form a second thoracic segment. Within the opercular crown, primary opercular paleae replace settling paleae.
The effects of season and exposure to reduced pH (abrupt and gradual) on some physiological parameters in brown trout (Salmo trutta)
Authors: Stuart Sally , Morris Ron
Published: March 2009

Body ions and compartments were measured in brown trout (Salmo trutta) maintained at ambient pH 7.0 throughout the year. The effects of abrupt and gradual transfer to reduced ambient pH were also studied. Seasonal variations occurred in blood hematocrit and in plasma and muscle Na+ and K+ concentrations at ambient pH 7.0. Similar trends were seen with reduced ambient pH. Fish seemed to be more susceptible to acid pHs during the summer months, with the majority of body Na+ loss occurring from the extracellular fluid and K+ loss from the intracellular fluid. Effects of reduced pH were more severe in fish directly transferred to reduced pH than in those which had previously encountered a reduced pH, suggesting that in the latter, some degree of physiological adaptation had taken place.
Reproductive success of Great Blue Herons in British Columbia
Authors: Forbes L. Scott , Simpson Keith , Kelsall John P. , Flook Donald R.
Published: March 2009

Great Blue Herons (Ardea herodias) in 14 colonies in southwestern British Columbia fledged a mean of 2.5 young per successful nest between 1977 and 1981; annual values varied by 12% around the 5-year mean, being highest in a dry spring and lowest in a wet spring. Herons in large colonies in British Columbia reared more young with lower variability in reproductive success than herons in small colonies, but not significantly so (p > 0.10). When data for all Canadian heronries were analyzed, the difference was significant (p < 0.05). Herons in western Canada reared more young than herons in the western United States (p < 0.025). Mortality in herons in western Canada was also higher than in herons in the western United States (p < 0.005).
Toxicity of aluminum and hydrogen ions to Daphnia catawba, Holopedium gibberum, Chaoborus punctipennis, and Chironomus anthrocinus from Mirror Lake, New Hampshire
Authors: Havas Magda , Likens Gene E.
Published: March 2009

The effect of aluminum on the survival of Daphnia catawba, Holopedium gibberum, Chaoborus punctipennis, and Chironomus anthrocinus was determined. Experiments were conducted in soft water adjusted to pH 6.5 (original), 5.0, 4.5, 4.0, and 3.5, at three concentrations of aluminum (0.02, 0.32, 1.02 mg/L) which cover the range typical of soft-water lakes exposed to acidic precipitation in eastern North America. Our results indicate that D. catawba was the most acid sensitive of the four species tested. It died rapidly below pH 5.0, whereas the others could survive at pHs as low as 4.0 (H. gibberum) and 3.5 (C. punctipennis and C. anthrocinus). None of the invertebrates were particularly sensitive to aluminum. Mortality, attributable to aluminum, occurred only at pH 6.5 for D. catawba at the highest aluminum concentration tested (1.02 mg/L). Most of the aluminum in this treatment was present as a solid-phase aluminum hydroxide complex. Based on our results, these species should be able to tolerate aluminum concentrations in excess of those which now occur in recently acidified oligotrophic lakes. If they are eliminated from acidic environments it is likely to be due to competition for food and (or) prédation pressure rather than direct aluminum toxicity.
Demography of Microtus pennsylvanicus in Southern Ontario: enumeration versus Jolly–Seber estimation compared
Authors: Boonstra Rudy
Published: March 2009

A meadow vole population near Toronto went through a cycle in numbers from July 1978 to May 1982. The population never reached a density less than 96 voles/ha or greater than 630 voles/ha. Jolly–Seber estimates differed from total enumeration counts by an average of 10.6% in population size and by less than 0.03 per 2 weeks in survival rates for almost all periods. Sharp spring declines occurred in both sexes in both the increase and the peak years, but only among females in the decline year. Dispersal occurred more frequently during the spring of the increase and peak than of the decline, was associated with maturation, and was biased towards males. The breeding season lasted 9 months in the increase and decline but only 5 months in the peak. Survival of adults during the decline summer was no different from that in other years. Survival of young during the increase and peak was moderately high, but was extremely poor during the decline. Since most young failed to be captured in either pitfalls or live-traps, I conclude that they died shortly before or after weaning and suggest that maternal condition was impaired by prior events in the peak and that this may apply to other cyclic microtine populations.
Comparative morphology of preextrusion larvae of the North Atlantic sharp-beaked red fishes, Sebastes mentella and Sebastes fasciatus (Pisces: Scorpaenidae)
Authors: Penney Randy W.
Published: March 2009

Preextrusion larvae of the ovoviviparous scorpaenid fishes, Sebastes mentella and Sebastes fasciatus, identified by the gas-bladder musculature characteristics of the parent, are described. Morphometrics, meristics, and pigmentation characteristics were recorded for late-stage preextrusion larvae taken from adult females on St. Pierre Bank, an area immediately south of and adjacent to the island of Newfoundland, Canada. The morphology of preextrusion larvae of S. mentella, in comparison with S. fasciatus, is described in detail for the first time. Univariate statistics were calculated and the utility of each of several morphometric, meristic, and pigmentation variables as a potential species identification criterion was evaluated. Discriminant analysis correctly classified up to 95% of larvae examined. The potential of the discriminant function in species identification for planktonic larvae is discussed.
Female pheromone and the behaviour of male guppies (Poecilia reticulata) in a temperature gradient
Authors: Johansen P. H.
Published: March 2009

When the two sexes of the guppy are tested separately in a horizontal temperature gradient apparatus, males show a significantly lower temperature preference (23.5 °C) than females (27.4 °C). However, when the two sexes are tested together, males select the same location as the females. Infusion of female holding water, which contains sex pheromone, results in the attraction of males to the site of infusion, as does the infusion of a water mixture of estradiol-17β, but not estrone, estriol, or testosterone. Temporarily plugging the nares, thereby blocking olfaction, prevents the males from responding to the chemical cues.
The peripheral metabolism of thyroid hormones and regulation of thyroidal status in poikilotherms
Authors: Eales J. G.
Published: March 2009

Available data from poikilotherms (primarily salmonid teleosts and larval amphibians) indicate that, as in the intensively researched mammals, peripheral regulation of thyroidal status takes place. An extreme but physiologically plausible model is that the thyroidally secreted thyroxine (T4) is an inactive prohormone; the hypothalamic–hypophyseal–thyroidal axis may merely ensure that adequate T4 is secreted to serve as a substrate for conversion, by extrathyroidal 5′-monodeiodinase activity in various tissues, to the active thyroid hormone (TH), 3,5,3′-triiodo-L-thyronine (T3). Regulation of thyroidal status may be achieved at several peripheral levels by altering (i) TH transport from plasma into tissues, (ii) tissue T4 5′-monodeiodinase activity, and (iii) the capacities and possibly affinities of putative nuclear T3 receptor sites. Blind assumption in poikilotherms of the superficially similar mammalian model can be highly misleading since major differences exist between poikilotherms and mammals in (i) plasma protein – TH interactions, with secondary effects on plasma TH levels and kinetics, and (ii) pathways of T4 deiodination, possibly related to differences in iodide economy. In contrast, the nuclear TH receptor properties are phylogenetically conservative. However, the factors influencing their properties have been scarcely studied. In this regard variable body temperature, the distinguishing feature between poikilotherms and homeotherms, remains largely unexplored.
Serotonin localization in the gills of the freshwater mussel, Ligumia subrostrata
Authors: Dietz T. H. , Steffens W. L. , Kays W. T. , Silverman H.
Published: March 2009

Exogenous serotonin stimulates sodium influx in Unionid mussels and in isolated gill tissue, which suggests that sodium transport in mussels is regulated by serotonin. The present study was an attempt to localize endogenous serotonin within the gill of Ligumia subrostrata. Examination of the gills at the light and electron microscopic levels revealed extensive branchial nerve tracts lying anterior–posterior between the adjacent gill filaments of each lamellar surface. In addition, there was a smaller nerve tract lying along the base of the water channel epithelium. These nerve tracts have a distinctive organization (containing nerve fibers and peripheral glial interstitial cells with gliosomes) and are capable of incorporating the vital dye procion yellow. Serotonin fluorescence following exposure to formaldehyde vapor was limited to the area of the nerve tracts. The identification of serotonergic neurons was further confirmed by light microscopic autoradiographs displaying silver grains localized principally over nerve tracts in gills exposed to tritiated serotonin. These morphologic data are consistent with the hypothesis, generated by previous physiologic data, that Na transport in freshwater Unionids is regulated by a neural serotonergic (cAMP-mediated) mechanism.
Seasonal testosterone levels, testosterone clearance, and testicular weights in male domestic cats
Authors: Kirkpatrick Jay F.
Published: March 2009

Concentrations of plasma testosterone, testosterone clearance rates from plasma, and testicular weights were measured in domestic tomcats during March, June, September, and December. Testicular weights showed a seasonal pattern, with significantly higher values in June than in December and March; however, sperm were present in the seminiferous tubules during all four seasons. The correlation coefficient between seasonal testicular weights and plasma testosterone concentrations was r = 0.929 (P < 0.05). Testosterone clearance rates indicated a half-life of 9.2 ± 2.3 min with no significant differences during the 4 months studied. These data suggest that tomcats are not seasonal breeders, but that there is a positive photoperiodic control of testicular weights. Fluctuations in plasma testosterone concentrations are moderated by testosterone production rather than by changes in testosterone clearance.
Nest sites and superclutches of American avocets on artificial islands
Authors: Giroux Jean-François
Published: March 2009

I studied American avocets (Recurvirostra americana) nesting on artificial islands in southeastern Alberta from 1976 to 1978 and in 1980. I found a total of 383 nests on 101 (53%) of the 191 islands searched. Solitary nesting occurred on 31 (16%) of the islands, whereas more than two nests were established on 70 (37%) islands. The average size of the colonies was 5.0 nests with a maximum of 18. Avocets appeared to prefer islands covered with the greatest amount of sparse vegetation and those surrounded by deeper water. Island use was greater during a drought in 1977 than during 1976 or 1978, when average weather conditions prevailed. The use of artificial islands by nesting avocets increases the benefits of this management technique originally designed for nesting waterfowl. The most frequent clutch size was four eggs. However, 15.4% of nests had six to eight eggs, possibly because two females laid their eggs in the same nest. These superclutches occur more frequently in the northern part of the avocet breeding range than in areas located at lower latitudes. I found the smallest percentage of superclutches in 1977, the drought year. Nest density was higher on islands with six- to eight-egg clutches than on those with only single clutches. Distances to the nearest conspecific nest and to the nearest shoreline did not differ between single and superclutches.
Bionomics of Dytiscus alaskanus J. Balfour-Browne (Coleoptera: Dytiscidae) in a central Alberta lake
Authors: Aiken R. B. , Wilkinson C. W.
Published: March 2009

There are few studies of life history and population growth of large dytiscid beetles in North America. We sampled populations of Dytiscus alaskanus in a eutrophic lake in north central Alberta weekly in the summers of 1982 and 1983. Like many other temperate zone dytiscids, D. alaskanus has a univoltine life cycle. Dytiscus alaskanus prefers the area at the limit of emergent vegetation in the lake and is most often associated with shoreline vegetation of cattail and sedge. Populations of adult D. alaskanus are at a peak in the late spring and decline throughout the summer. Mark–recapture experiments allowed determination of total population size and monitoring of movement patterns in the lake. Data are discussed with reference to the relatively short summer with which these beetles must cope.
An empirical evaluation of several univariate methods that adjust for size variation in morphometric data
Authors: Reist James D.
Published: March 2009

A variety of univariate transformations that attempt to separate size and shape variation are available: logarithms, ratios, logarithms of ratios, allometric adjustment, and regression techniques (major axis, residuals). Using the same basic data set derived from morphometric measurements of a freshwater fish, these transformations were examined for their effects upon variable distributions, correlations, and covariances. Those that were at least partly effective in removing size variation affected the correlation and covariance structure of the data in different ways, and thus resulted in different biological interpretations for principal component and discriminant analyses. Adjustment of size using a regression technique (computation of residuals from a standard size axis) or allometric adjustment to a standard size was preferred because these allowed for the complete removal of size variation and adverse effects were minimal. Although the actual estimates of shape were different for these two transformations, the relationships that resulted between groups inherent in the data were very similar. If heterogeneity between samples exists in the regression slopes or the allometric coefficients, the common within-groups slope or coefficient must be used to adjust for size.
Helminth parasites of Thomomys bulbivorus (Richardson) (Rodentia: Geomyidae), with the description of a new species of Hymenolepis (Cestoda)
Authors: Gardner Scott Lyell
Published: March 2009

A cestode, Hymenolepis tualatinensis n. sp., is described from the pocket gopher, Thomomys bulbivorus (Richardson) (Rodentia: Geomyidae), from the Willamette Valley in Oregon. Helminths of four additional species were found. Trichuris fossor Hall, 1916, Ransomus rodentorum Hall, 1916, Heligmosomoides thomomyos Gardner and Jasmer, 1983, and Hymenolepis horrida (von Linstow, 1901), of which all but H. thomomyos represent new host records. A significant change in prevalence of the whipworm T. fossor in the population of T. bulbivorus from spring through summer was noted. Significant differences in prevalence of infection of helminths in pocket gophers collected from two different localities in the Willamette Valley were observed.
Ultrastructure of the tegument and penetration glands of developing procercoids of Haplobothrium globuliforme Cooper, 1914 (Cestoda: Haplobothrioidea)
Authors: MacKinnon Barbara M. , Jarecka Leokadia , Burt Michael D. B.
Published: March 2009

Developing procercoids of Haplobothrium globuliforme were examined using transmission electron microscopy. Procercoids require 12–20 days, at approximately 20 °C, to develop to the infective stage. Six-day-old procercoids have a microvillar tegument and numerous undifferentiated subtegumental cells. In 9-day-old procercoids the cercomer is visible as a distinct appendage at the posterior end. Developing microtriches are evident on the tegument of the larval body. These are long and slender, and bear small electron-dense tips. No degenerating microvilli were evident and the microtriches were never seen emerging de novo from the tegument. Fully developed procercoids, 15 days postinfection, have both robust and slender microtriches at the anterior end of the larva, and only long slender microtriches over the remainder of the body. The cercomer retains a microvillar tegument until the larva is fully developed, at which time the tegumental projections on the anterior-most part of the cercomer bear small electron-dense tips. Penetration glands in the anterior part of the larva contain electron-dense secretory granules. The penetration gland ducts, which extend to the tegument, are lined with microtubules.
The comparative ultrastructure of the plerocercoid and adult primary scolex of Haplobothrium globuliforme Cooper, 1914 (Cestoda: Haplobothrioidea)
Authors: MacKinnon Barbara M. , Burt Michael D. B.
Published: March 2009

Plerocercoids of Haplobothrium globuliforme recovered from the liver of Ictalurus nebulosus and adult cestodes from the intestine of Amia calva were examined using light and electron microscopy. Both plerocercoids and adults have four eversible proboscides on the scolex. Using light microscopy, a lumen is evident in the centre of each proboscis, through which the proboscis retracts during inversion into the muscular sacs contained within the scolex. Each proboscis contains numerous glandular sacs. Staining with Heidenhain's azan indicates that cells in the neck region of the cestode probably produce the secretory material for these glandular sacs. Ultrastructurally, the tegument of plerocercoid and adult scolices are remarkably similar. The distal tips of each proboscis are covered with short microtriches (0.25 μm long) which have poorly defined electron-dense tips. Nearer the base of the proboscides, the tegumental microtriches elongate and bear delicate, slender tips. Around the base of the proboscis, these microtriches are interspersed with robust spinelike microtriches (6.0 μm long) which have a clublike tip and which are anchored into the tegument by cup-shaped roots. Throughout the entire length of the proboscis, subtegumental glandular sacs are present. These have been seen to fuse with the tegumental cytoplasm. Covering the lateral surfaces of the scolex are the slender, delicate microtriches interspersed with angular, robust microtriches (2.0 μm long). The remainder of the scolex and neck regions are covered with small peglike microtriches which are somewhat longer in the adult (1.0 μm) than in the plerocercoid (0.8 μm). The tegumental cytoplasm in the neck region of the plerocercoid has a stratified appearance, with membrane-bound electron-lucent vesicles occupying the distal portion, and lamellar bodies and large mitochondria forming a layer near the inner plasma membrane. The adult tegumental cytoplasm lacks this stratification and contains electron-dense discs and occasional electron-lucent vesicles. The plerocercoid of H. globuliforme appears to be the developmental stage that preadapts the cestode for its adult existence in the definitive host's intestine.
Distribution and reproductive seasonality of snailfishes and lumpfishes in the St. Lawrence River estuary and the Gulf of St. Lawrence
Authors: Able Kenneth W. , Irion Wendy
Published: March 2009

The distribution of two lumpfishes and nine snailfishes was determined from a variety of samples from the St. Lawrence River estuary and Gulf of St. Lawrence. Two of these (Paraliparis calidus and P. copei) are recorded for the first time. Two others (Liparis gibbus and L. fabricii) reach their southern limit in the study area, while two others (L. coheni and L. inquilinus) may not occur further north. The Careproctus species found appear to be C. reinhardti (abundant) and C. ranula (rare). These species can be distinguished by selected meristic characters, especially pyloric caeca, pectoral fin shape, and size at maturity. All species examined spawn in the spring and summer except L. coheni, which probably spawns during the winter.
Seasonal changes in the critical thermal maxima of fantail (Etheostoma flabellare), greenside (Etheostoma blennioides), and rainbow (Etheostoma caeruleum) darters
Authors: Hlohowskyj Ihor , Wissing Thomas E.
Published: March 2009

Seasonal critical thermal maxima (CTMax) were determined for greenside (Etheostoma blennioides), fantail (Etheostoma flabellare), and rainbow (Etheostoma caeruleum) darters. Mean CTMax values for field-acclimatized greenside darters ranged from 26.2 °C in March to 35.1 °C in September. The values for fantail and rainbow darters were 30.8–36.0 °C (March–July) and 30.0–36.4 °C (April–July), respectively. CTMax values for the three species were significantly correlated (P < 0.05) with field water temperature (greenside darter, r = 0.970; rainbow darter, r = 0.964; fantail darter, r = 0.968). Fish acclimated at 10 and 20 °C in the laboratory exhibited significant seasonal changes in CTMax, with the highest values occurring in the summer. Except for fantail darters tested in summer, the three species showed significant relationships between CTMax and acclimation temperature. Seasonal differences were also observed in the slopes of the relationships between CTMax and acclimation temperature. The highest slopes occurred in spring, autumn, or both. Differences in the tolerance of darters to high temperatures and adjustment of tolerance to high temperature may influence their distributions in streams.
Spermatophore size and its role in the reproductive behaviour of the cricket, Gryllodes supplicans (Orthoptera: Gryllidae)
Authors: Sakaluk Scott K.
Published: March 2009

The spermatophore that a male cricket of Gryllodes supplicans transfers to the female during mating, includes a large gelatinous portion (spermatophylax) that is removed and consumed by the female after mating. In other North American cricket species, the spermatophore consists solely of a small sperm-containing ampulla. In this study, the role of spermatophore size in the reproductive behaviour of G. supplicans was examined, along with the costs associated with the provision of a more complex spermatophore. The mean intercopulatory interval of male G. supplicans that were allowed constant access to receptive females was 3.25 h; this period is long relative to those of other crickets. The estimated weight of spermatophores produced by males did not differ significantly from that of spermatophores produced by these same males 24 h later; males apparently hold constant their investment in subsequent copulations. The time taken by females to consume the spermatophylax fully increased linearly with the weight of the spermatophore. Females remove the sperm ampulla soon after consuming the spermatophylax and thus penalize males that provide smaller "nuptial meals." Larger males produce heavier spermatophores; thus, small males often may be at a selective disadvantage. These results, when examined in the light of the ampulla-removal behaviour of females, suggests that females are capable of adaptive mate choice.