bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental evidence of size-dependent predation mortality in juvenile yellow perch
Authors: Post John R. , Evans David O.
Published: March 2009

Adult yellow perch, Perca flavescens, when offered equal numbers of small (52 – 59 mm total length) and large (66 – 73 mm total length) conspecifics, selected more small than large prey in 9 of 11 laboratory feeding trials. The small and large groups were selected from the smallest 40% and largest 15% of a natural length–frequency distribution of young-of-the-year yellow perch captured in the fall of 1985 from Dickie Lake, Ontario. The adult yellow perch predators ranged in size from 23.2 to 26.8 cm total length. Our experiment suggests that smaller individuals of a juvenile yellow perch cohort have a greater risk of mortality owing to size-selective predation than do larger individuals. Factors that affect the growth rate of juvenile yellow perch may therefore influence recruitment by modifying the extent of size-dependent predation mortality.
Seasonal population dynamics and maturation of Neoechinorhynchus pungitius (Acanthocephala: Neoechinorhynchidae) infecting brook stickleback, Culaea inconstans, from Sioux Creek, Wisconsin, U.S.A.
Authors: Lasee Becky A.
Published: March 2009

Seasonal population dynamics and maturation of the acanthocephalan Neoechinorhynchus pungitius from brook stickleback (Culaea inconstans) were investigated. Stickleback were collected monthly at Sioux Creek, Wisconsin from April 1981 to May 1982 (excluding December, January, and February). Forty-seven percent (292/620) were infected with N. pungitius, which exhibited seasonal periodicity in prevalence, mean intensity, and maturation. Prevalence and mean intensities were lowest in summer and increased through autumn owing to recruitment of juvenile and immature worms. Prevalence and mean intensity reached their peaks by April and May, and N. pungitius infrapopulations were composed primarily of mature worms. Egg production began in May and continued throughout early summer. Neoechinorhynchus pungitius males appeared shorter lived than females, as the June and July infrapopulations were comprised mostly of females. Prevalence and mean intensity of N. pungitius increased as brook stickleback length increased. There was no significant difference between numbers of male and female fish infected or between mean intensity and host sex.
Energy metabolism and thermoregulation of beaver (Castor canadensis)
Authors: MacArthur Robert A.
Published: March 2009

Metabolic rates and body temperatures (Tb) of adult and immature beavers were recorded at air temperatures from −20 to 28 °C. The thermoneutral zone of beavers > 1 year of age extended from 0–2 °C to at least 28 °C. Lower critical temperature, whole-body conductance, and resting metabolic rate were similar for yearlings and beavers ≥ 2 years old, and conformed closely to weight-predicted values for terrestrial eutherians. The estimated lower critical temperature of a growing beaver kit declined from 24–25 °C at 2–3 weeks of age when the animal weighed 0.59–0.62 kg to 0–2 °C at 11–13 weeks when the kit weighed 2.92–3.50 kg. Rectal Tb of the kit was generally lower and less stable than abdominal Tb recorded telemetrically from older animals. In beavers > 1 year old, abdominal Tb was independent of air temprature (−20 to 28 °C), with no evidence of hypothermia or metabolic depression at subfreezing temperatures. Neither the level nor the daily rhythm of Tb was substantially altered by 24–48 h fasting in this species.
The energy budget of adult Pseudopachymerina spinipes (Er.) (Coleoptera: Bruchidae)
Authors: Yates L. R. , Daza M. , Sáiz F.
Published: March 2009

This paper describes the energy budget dynamics of adults of the bruchid Pseudopachymerina spinipes (Er.), based on changes in body weight and biomass caloric content, and heat dissipation by respiration, all as affected by age, sex, and temperature. Pseudopachymerina spinipes develops in Acacia caven seeds, consumes its cotyledons, and emerges to mate and oviposit without the need for water or further food consumption. The beetles died when 65% of the energy reserve accumulated as lipid during the larval stage is consumed. This amount of lipid represents approximately 41% of the body mass at emergence. The life-span depended on the rate of body water loss and on the metabolic rate, independent of the initial body biomass. The adults used lipids as a source of energy to support their metabolic activity. Oxygen consumption decreased with age in males, but only at temperatures above 20 °C. Age did not influence respiration in females at the experimental temperatures. Increasing temperature triggered an increase in levels of and individual variability in oxygen consumption. The respiration rate of males was higher than that of females, particularly at 15 and 21 °C. Thus, females live longer than males and longevity is shorter in both males and females during warmer periods.
Shell dropping by Northwestern Crows: a reexamination of an optimal foraging study
Authors: Plowright R. C. , Fuller G. A. , Paloheimo J. E.
Published: March 2009

The report by Zach (Zach, R. 1979. Behaviour, 68: 106–117) that Northwestern Crows (Corvus caurinus), when breaking whelks, drop the shells from an optimal height is reexamined. The currency used by Zach is arguably inappropriate because of the significant handling costs incurred by the birds in the shell-breaking process. As the birds ascend to a lower height than is predicted by any of the optimality models examined in this paper, it is suggested that their behaviour should not be cited as an example of the successful application of optimal foraging theory.
Research publications on Canadian mammals, 1971–1986
Authors: Dagg Anne Innis
Published: March 2009

A survey was made of the 1124 research papers dealing with wild mammals living in Canada published in 11 relevant biological journals from 1971 to 1986. This study extends an earlier survey carried out by the author for the years 1931–1970. Canadian journals in general, and the Canadian Journal of Zoology in particular, published most of the research papers, which are far more numerous than they were in the earlier period. Research papers are increasingly written by two or more authors, and there seems to be a different pattern of publishing for women than for men. Most research was done by university personnel, who came from 35 Canadian (and a number of American) universities. Field studies in general were more numerous in the more densely populated provinces, although more studies were carried out in the Northwest Territories than in any other jurisdiction. The Canadian Federal Government financed most research projects, followed by Provincial and Territorial governments, and Canadian universities. However, well over 50 different groups or institutions funded at least a few studies each. The most studied subjects were behavior, anatomy and physiology, populations, and ecology and habitat. The most studied species were small mammals, large carnivores, seals that are hunted, and big game species. The mammals studied least were insectivores, bats, lagomorphs, and whales.
Chemical elements in mineral licks and associated muskoxen feces in Jameson Land, northeast Greenland
Authors: Klein David R. , Thing Henning
Published: March 2009

Chemical analyses of soil from several mineral licks used by muskoxen (Ovibos moschatus) showed consistently higher content of sodium than did soil outside the lick sites. Other minerals were more variable in their distribution in the samples, although potassium, magnesium, and iron were often substantially more abundant in soil from the licks than in adjacent soil. Analysis of fecal samples that contained large amounts of soil believed to be from one lick showed higher proportions of sodium, iron, magnesium, and calcium than did fecal samples collected far from any known lick. We believe that sodium is the primary element sought by muskoxen using the mineral licks. This appears consistent with the high seasonal physiological requirements for sodium of ruminants, its relatively low availability in the forage, and the high potassium and water content of forage during the season of lick use, both of which are known to interfere with sodium retention.
The infl1uence of physical clutter and noise on the activity of bats over water
Authors: Mackey Robin L. , Barclay Robert M. R.
Published: March 2009

To determine why some bats concentrate their activity over calm water rather than turbulent water, we studied the effects of surface clutter and running-water noise on the foraging activity of Myotis lucifugus (little brown bats), which commonly fly within 0.5 m of the water surface, and Eptesicus fuscus (big brown bats), which forage at greater heights, in southwestern Alberta, Canada. In paired experiments over calm water, artificial clutter reduced the activity of M. lucifugus, but not that of E. fuscus, compared with natural conditions. Playbacks of the sound of turbulent water reduced the activity of both M. lucifugus and E. fuscus in paired experiments over calm water. Clutter is an obstacle to flight and produces extraneous background echoes that must be discriminated from prey echoes. Water noise may also interfere with prey detection. The result may be reduced foraging efficiency by bats and a preference for calm bodies of water over turbulent ones.
Experimental infection of reindeer with Elaphostrongylus (Nematoda; Protostrongylidae) originating from reindeer, red deer, and moose
Authors: Halvorsen Odd , Skorping Arne , Bye Karstein
Published: March 2009

To test the hypothesis that palearctic cervids are infected with several species of Elaphostrongylus, reindeer (Rangifer tarandus tarandus) calves were inoculated with third-stage larvae grown in Arianta arbustorum from first-stage larvae extracted from reindeer, red deer (Cervus elaphus atlanticus), and moose (Alces alces) feces. None of the five reindeer calves inoculated with larvae from red deer and none of the three reindeer calves inoculated with larvae from moose became infected. Twelve of the 14 reindeer calves inoculated with larvae from reindeer became infected. Infection was demonstrated by finding first-stage larvae in the feces and (or) by finding worms at necropsy. These results suggest that several species of Elaphostrongylus parasitize palearctic cervids. In view of our results and the need for further taxonomic work on the group, it is argued that the names Elaphostrongylus cervi and Elaphostrongylus rangiferi should be reserved for worms from red deer and reindeer, respectively. Worms from moose may belong to an undescribed species.
Prey selection and habitat partitioning in sympatric coyote and red fox populations, southwest Yukon
Authors: Theberge John B. , Wedeles Chris H. R.
Published: March 2009

Sympatric coyotes (Canis latrans) and red foxes (Vulpes vulpes) in the southwest Yukon, studied across the peak of a snow-shoe hare (Lepus americanus) cycle, differed little from one another in prey selection, and both were heavily dependent on snowshoe hares. After the hare crash, however, foxes turned more to alternative prey than did coyotes. Foxes and coyotes differed in their selection of habitat patches and use of edge. Coyotes exploited edges, where hares were most abundant, and open communities, whereas foxes showed no significant use of edge and used brushy communities. The coexistence of red foxes and coyotes in the southwest Yukon may be facilitated by balancing competitive abilities: foxes persist because of elasticity in their choice of prey and coyotes persist by dominating edges.
Size and winter survivorship in neonatal western rattlesnakes (Crotalus viridis)
Authors: Charland M. Brent
Published: March 2009

The interaction between size at birth and early survivorship has received considerable theoretical attention in a variety of taxa. However, collecting empirial data to test these hypotheses has proved difficult, especially among ectotherms such as snakes. In this study, I examined winter survivorship of neonatal western rattlesnakes (Crotalus viridis) with respect to size at birth and site of hibernation. I collected 115 neonatal C. viridis in the fall of 1985, divided the sample into two groups, and released them to hibernate at two winter dens. Recaptures suggest that minimum survivorship during the winter of 1985 – 1986 was about 55% and that survivorship was independent of both weight and condition at birth. Young released at the two dens differed in both the pattern and amount of weight loss but not in survivorship. My results suggest that any survival advantage conferred by size at birth either varies annually or occurs during the first active season when food for small snakes may be difficult to obtain.
Seasonal variations in testis size, testosterone and LH basal levels, and pituitary response to luteinizing hormone releasing hormone in the brown hare, Lepus europaeus
Authors: Caillol M. , Meunier M. , Mondain-Monval M. , Simon P.
Published: March 2009

In the brown hare, fertile mating takes place from the beginning of December to September. Seasonal variations of testis size, plasma levels of LH and testosterone, and pituitary and testicular responses to a monthly i.v. injection of 5 μg LHRH were studied in adult hares. Testis recrudescence began in October, 2 months before the beginning of the breeding season. The gonads were fully developed between January and July, and regressed thereafter. The increase of testosterone basal levels paralleled testicular growth, despite undetectable levels of LH. These LH levels increased slightly from April to August, when testosterone secretion decreased. Luteinizing hormone releasing hormone (LHRH) injection was always followed by a release of LH; the LH value peaked 15 min after injection and returned to basal concentrations 2 h later. The pituitary response to LHRH was significantly higher in July (76.4 ± 11.2 ng/mL, n = 5) and August (60.1 ± 5.6 ng/mL, n = 5), at the end of the mating season. The LH surge induced by LHRH was always followed by a secretion of testosterone lasting approximately 2 h. This testosterone secretion was maximum in January (88.6 ± 23.9 ng/mL, n = 5) and February (81.3 ± 18.6 ng/mL, n = 5), when the testis is fully developed. This suggests an increase in the pituitary content of LH in July and August, when day length decreases and testosterone negative feedback is less effective. These high LH levels might be responsible for the testis recrudescence 2 months later.
Androgens impair seawater adaptability in smolting Baltic salmon (Salmo salar)
Authors: Lundqvist H. , Borg B. , Berglund I.
Published: March 2009

Sexually immature (females and males) and mature male two-summer-old Baltic salmon (Salmo salar) were implanted with silastic capsules containing testosterone or 11-ketoandrostenedione in spring before the smoltification period. The seawater adaptability of the hormone-treated fish and intact control fish or control fish implanted with empty capsules was tested periodically from May to July using a common seawater challenge test with 25‰ saltwater. Fish were selected from the Norrfors hatchery stock (Ume River, (63°50′N, 20°05′E)) and ranged in fork length from 13 to 17 cm. At all sampling times the immature control fish displayed a better seawater adaptability than the previously mature males. Both groups exhibited a seasonal smoltification pattern with maximal adaptability in mid-June, when the mean plasma sodium levels after challenge were 161 mmol in the immature and 193 mmol in the mature fish. At all times both androgens impaired the seawater adaptability of the immature fish, which displayed high sodium levels comparable to those in untreated previously mature males. Even higher sodium levels were reached in previously mature males treated with androgen capsules. However, in all categories of fish the lowest levels of plasma sodium were found at the same time in mid-June. This indicates that although there is a marked, negative effect of sexual maturation and androgens on seawater adaptability, the temporal organization of smoltification is not affected.
Echinocotyle capensis n.sp. (Cestoda: Hymenolepididae) from South African waterfowl
Authors: McLaughlin J. D.
Published: March 2009

Echinocotyle capensis n.sp. is described from Cape shovelers (Anas smithii (Hartert)) and Cape teal (Anas capensis Gmelin) collected at Barberspan, Transvaal Province, Republic of South Africa. Echinocotyle capensis is a small cestode up to 1.62 mm long with 10 rostellar hooks 50–55 μm long. It most closely resembles Echinocotyle singhi Srivastava and Pandey, 1980 but has slightly longer rostellar hooks and a shorter cirrus sac, and lacks the vaginal sphincter present in E. singhi.
On the error involved in high-speed film when used to evaluate maximum accelerations of fish
Authors: Harper David G. , Blake Robert W.
Published: March 2009

An analysis of hypothetical, film-derived, and accelerometer-measured acceleration–time data of fish fast starts indicates that the total error in film studies is the sum of sampling frequency error (i.e., the error due to over-smoothing at low film speeds) and measurement error. Measurement error depends on the digitizing apparatus, the image magnification, and the magnitude of the acceleration in question. Total error approaches a minimum at an optimal film speed determined by the magnification of the image. This error is reduced by increasing image magnification and by selecting a new (higher) film speed. Theoretical expectations of total error were tested experimentally by comparing statistically differentiated film records with accelerometer records of fast starts in fish. Average experimentally determined error, for a range of film speeds, was found to be within 13% of the theoretical average. Accelerometer data recorded during fast starts of pike indicate that previous assessments have underestimated performance. The maximum acceleration rate here, for a C-type escape, was 241.2 m∙s−2, more than twice that previously reported for any fish.
Données quantitatives et observations histologiques sur la pachyostose du squelette du dugong, Dugong dugon (Müller) (Sirenia, Dugongidae)
Authors: Buffrénil Vivian de , Schoevaert Damien
Published: March 2009

La pachyostose du dugong consiste en une hyperostose des corticales et en un accroissement de la densité des os. Cette dernière est produite par l'augmentation simultanée de la compacité et de la minéralisation du tissu osseux. Cette particularité structurale est circonscrite aux régions céphalique et thoracique et semble associée à la position qu'occupent les os dans le squelette. L'élévation de la compacité osseuse est due à l'affaiblissement de la résorption ostéoclasique ainsi qu'à la compaci-fication de la région médullaire par des dépôts endostéaux centripètes. Les déterminismes endocriniens possibles de ces processus sont discutés, de même que la valeur adaptative éventuelle de la pachyostose.
Microhabitat and prey size among three species of Rana (Anura: Ranidae) sympatric in eastern Canada
Authors: McAlpine Donald F. , Dilworth Timothy G.
Published: March 2009

Microhabitat, prey size, and body morphology were examined in sympatric leopard frogs (Rana pipiens), green frogs (R. clamitans), and bullfrogs (R. catesbeiana) at a site in central New Brunswick. Ratios of head widths among species pairs were 1.23 (leopard and green frogs) and 1.51 (bullfrogs and green frogs), suggesting that leopard and green frogs may take prey of similar size. Analysis of stomach contents showed no significant differences in the mean prey sizes selected by leopard and green frogs. Rana sp. figured prominently in the diet of bullfrogs at the study site. Overlap among the species for prey length indicates the potential for competition between green and leopard frogs (Pij = 0.40 versus Pij = 1.41 for green frogs and bullfrogs). Structural aspects of habitat associated with vegetation were most important in discriminating microhabitat. Leopard frogs selected microhabitats that were much more densely vegetated than those of either bullfrogs or green frogs. In water, green frogs occupied sites that were closer to shore, were of lower water temperature, and had a higher vegetation canopy than sites occupied by bullfrogs. On land, green frogs selected microhabitats that were closer to water and less densely vegetated than those of leopard frogs. There was much greater microhabitat separation between leopard and green frogs than between green frogs and bullfrogs. There is some evidence that predation (bullfrogs preying on green frogs) and perhaps past competition (between green frogs and leopard frogs) have contributed to the patterns of resource use described. A number of other potential mechanisms (i.e., species phylogenies, inherent physiological or behavioural constraints acquired independently of interspecific interactions) remain unevaluated.
The morphological adaptations of horse fly larvae (Diptera: Tabanidae) to developmental sites in the Palearctic Region and their relationship to the evolution and distribution of the family
Authors: Andreeva R. V.
Published: March 2009

Horse fly larvae occur in diverse biotopes, not only in swampy habitats, but also in lakes, ponds, and mountain streams, as well as in high mountain forests and meadows. An analysis of the morphology of horse fly larvae from all known biotopes has revealed that morphological features are correlated with habitat type. Published articles and monographs that treat the taxonomy and morphology of larvae of the Tabanidae, particularly in the Nearctic Region, demonstrate the morphological features of adaptive significance. However, these works do not relate habitat type directly to morphological adaptations. Horse fly larvae are here grouped as ecological types, based on their external anatomy rather than on accepted phylogenetic lineages. The ability of tabanid larvae to adapt to different biotopes has influenced the geographic distribution and perhaps the evolution of taxa of this family.
Hyalella azteca (Amphipoda) as an intermediate host of the nematode Streptocara crassicauda
Authors: Laberge Robert J. A. , McLaughlin J. Daniel
Published: March 2009

The life cycle of Streptocara crassicauda (Creplin, 1829) was studied experimentally in the amphipod Hyalella azteca (Saussure). Of 2946 H. azteca that survived exposure, 699 were infected. Developing larval stages were found almost exclusively in the cephalic haemocoel. At 18–20 °C, moulting first-stage larvae were observed initially on day 11 and moulting second-stage larvae on day 15 post infection. The moult was not synchronous and moulting stages were found for several days after the initial observation. Third-stage larvae were found as early as day 19 post infection. The larval stages found in H. azteca are described. Mature females containing larvated eggs were recovered from domestic ducks (Anas platyrhynchos dom.) 9–21 days post exposure, and eggs were found in fecal samples on day 26. None of the females recovered from ducks 42 days post infection contained larvated eggs.
Behavioral and physiological reactions of arctic seals during under-ice pilotage
Authors: Elsner Robert , Wartzok Douglas , Sonafrank Nancy B. , Kelly Brendan P.
Published: March 2009

One spotted seal (Phoca largha) and two ringed seals (Phoca hispida) were studied in experiments designed to determine which sensory modalities were employed in pilotage from one under-ice breathing hole to another. Breathing holes were drilled in the ice of a frozen freshwater pond and a lake near Fairbanks, Alaska. Holes were located 22–150 m apart. Tethered seals swimming without blindfolding located holes when they chanced to swim within visual detection distance. Blindfolded seals responded to acoustic signals. Tactile sensitivity of the vibrissae was used by blindfolded seals in the immediate vicinity of a hole to which they had been attracted by an acoustic cue. Responses of a juvenile ringed seal did not differ fundamentally from those of an adult of the same species nor from those of the spotted seal. The results indicate that seals relied upon a sensory hierarchy for locating breathing holes: vision, audition, and vibrissal sense. Heart rate was recorded during voluntary dives of the younger ringed seal at 2 and 3 years of age. Profound diving bradycardia was observed, suggesting that a highly developed diving response is routinely invoked by seals of relatively small body size during under-ice excursions.
Structure, ultrastructure et essai d'interprétation fonctionnelle de l'appareil génital femelle d'Hemidiaptomus ingens provinciae et de Mixodiaptomus kupelwieseri (Copepoda, Calanoida). I. Les oviductes
Authors: Cuoc Corinne , Arnaud Jean , Brunet Michel , Mazza Jacques
Published: March 2009

The structural and ultrastructural studies that we carried out on the oviducts in Hemidiaptomus ingens provinciae and Mixodiaptomus kupelwieseri, two fresh water calanoid copepods, revealed the presence of an epithelium organized in small syncytia with typically glandular features, namely, highly developed rough endoplasmic reticulum, numerous dictyosomes, and secretory granules. In the mature females, both the appearance of luminal secretions and the very clear ultrastructural differences observed between the organelles, particularly the secretory granules, allowed us to distinguish three zones: a proximal, median, and distal zone. All the secretions observed through the three zones play a role in the formation of the ovisac, in which the eggs are laid. During egg laying or immediately after, the lumen of the oviduct is very small and even undetectable in the proximal zone, whereas no secretion is observed in the median and distal zones. No additional structure, such as a seminal receptacle, was found associated to the genital ducts. Finally the oviduct wall is entirely devoid of any muscular network.
Populations of ferruginous and Swainson's hawks increase in synchrony with ground squirrels
Authors: Schmutz Josef K. , Hungle Daniel J.
Published: March 2009

We compared changes in the densities of breeding ferruginous (Buteo regalis) and Swainson's hawks (Buteo swainsoni) over a period of 9 years with the abundance of a major prey species, Richardson's ground squirrel (Spermophilus richardsonii). We used the amount of poison distributed by landowners annually in their attempts to reduce crop damage by ground squirrels as an index of ground squirrel abundance. Though ground squirrel abundance was positively correlated with hawk density overall, the hawks differed in their responses to changing prey density. Breeding density and fledging success of the ferruginous hawk, a food specialist, were consistently correlated with squirrel abundance. The density of Swainson's hawks increased only where grassland was interspersed with agricultural fields. Fledging success of Swainson's hawks was not correlated with ground squirrel abundance. We suggest that the availability of small prey in spring affected breeding dispersion and reproductive success of Swainson's hawks.
Changes in RNA and oxidative enzymes in Nephelopsis obscura (Erpobdellidae) as indices of environmental stress
Authors: Singhal R. N. , Davies Ronald W. , Sarnat Harvey B.
Published: March 2009

Low salinity concentrations (1.25 and 2.5 ppt), starvation (1–4 weeks), and temperature (15 °C) produce no changes in the acridine orange – RNA fluorescence of intestinal and tegumentary epithelial cell cytoplasm of Nephelopsis obscura. However, after exposure to 5.0 ppt salinity, or starvation for 5 weeks at 20 °C, ribosomal fluorescence becomes less intense and peripherally redistributed. The large, granular, orthochromatic mucus-secreting cells increase in number with increasing salinity and starvation, and glycogen increases in the muscular and epithelial layers. Nephelopsis obscura exposed to 5.0 ppt salinity show histochemical clumping of mitochondrial oxidative enzymatic activity in degenerating myofibres. Collagen and muscle proteins decrease with increasing salinity and starvation. Changes in oxidative enzymatic activity and RNA synthesis may serve as cytological markers of environmental stresses.
Food patch depletion by ruddy ducks: foraging by expectation rules
Authors: Tome Michael W.
Published: March 2009

The foraging behavior of six ruddy ducks (Oxyura jamaicensis) was studied in a large concrete and glass aquarium to determine if they used either a number or time expectation rule to decide when to leave a patch of food. Nine trials were conducted in which the prey density in each of two food patches remained constant for three consecutive trials and then was changed. If the foraging ruddy ducks were using an expectation rule to determine when to leave a patch, then the time spent in the patch (time expectation) or number of prey consumed from the patch (number expectation) should not change with a change in patch quality. The results of this experiment were not consistent with the predictions of either the time or number expectation rule. Thus, ruddy ducks appear to use some other measure to determine the appropriate time to leave a food patch.
Hepatozoon parus n.sp. from the Paridae and redescription of H. atticorae (de Beaurepaire Aragão, 1911) Hoare, 1924 from the Hirundinidae
Authors: Bennett Gordon F. , Peirce Michael A.
Published: March 2009

Hepatozoon parus n.sp. is described from the chickadees and titmice (Paridae) in North America and the United Kingdom. Hepatozoon atticorae (de Beaurepaire Aragão, 1911) Hoare, 1924 from swallows (Hirundinidae) is redescribed and the parasite is compared from hosts from North and South America, Jamaica, Europe, and South Africa.
Development of Skrjabinoclava inornatae (Nematoda: Acuarioidea) in fiddler crabs (Uca spp.) (Crustacea) and Western Willets (Catoptrophorus semipalmatus inornatus) (Aves: Scolopacidae)
Authors: Wong P. L. , Anderson R. C. , Bartlett Cheryl M.
Published: March 2009

Skrjabinoclava inornatae Wong and Anderson, 1988 from the posterior half of the oesophagus and proventriculus of Western Willets (Catoptrophorus semipalmatus inornatus (Brewster)) developed to the infective third stage in fiddler crabs (Uca spp.) collected in Louisiana, U.S.A. This is the first report of the development of an acuarioid in a decapod. The third-stage larva was characterized by a dorsally bowed caudal end and one small dorsal protuberance and two large dorsally directed spines on the tail tip. The genital primordia were precociously developed in both male and female third-stage larvae. Larvae transferred experimentally to uninfected willets were found in the mucosa of the proventriculus and underwent the first moult less than 3 days and the fourth moult 5 days postinfection. Adult worms occurred mainly in the posterior end of the oesophagus and were mature 15 days postinfection. It is suggested that the rapidity of maturation of the worms in willets may be related to the precocious development of the genital primordia in the third-stage larvae. Marbled Godwits (Limosa fedoa L.) were infected experimentally. American Avocets (Recurvirostra americana Gmelin) and Black Terns (Chlidonias niger (L.)) given larvae did not become infected.
Coordination of metabolism and intracellular acid–base status: ionic regulation and metabolic consequences
Authors: Walsh Patrick J. , Milligan C. Louise
Published: March 2009

This review discusses the mechanisms by which animal cells regulate intracellular pH (pHi), the variations in pHi encountered in vivo, and the impact that variations in pHi (and other acid–base variables) have on metabolism. Cells regulate pHi by a combination of (i) physicochemical buffering by intracellular components; (ii) transport of acids and bases across the plasma membrane; and (iii) production and consumption of acids and bases by metabolism. Ionic transport is by far the best studied of these three mechanisms, and several specific plasma membrane exchangers (e.g., Na+–H+ exchange) are important regulators of pHi The precise quantitative contribution of the other two mechanisms to pHi regulation awaits further study. Intracellular pH variations in vivo can be substantial (i.e., up to 1 unit in some cases) and can lead to marked changes in metabolism. Furthermore, changes in carbon dioxide tension and bicarbonate concentration can also affect metabolism. Catecholamines appear to be important regulatory signals in metabolic compensation for acid–base perturbations, but in some cases acid–base disturbances may produce adaptive metabolic changes directly.
Metabolic adjustments to breath holding in higher vertebrates
Authors: Butler P. J.
Published: March 2009

There is substantial behavioural and physiological evidence to suggest that most feeding dives by aquatic birds and mammals are aerobic in nature, with no net production of lactate. Any increase in lactate production is matched by increased removal. This does not mean, however, that there are no cardiovascular adjustments associated with such dives. Nonactive parts of the body (including the large pectoral muscles in diving ducks) may be hypoperfused and consume oxygen at a reduced rate. For example, in marine mammals, such as the Weddell seal, reduced perfusion of the gut during a feeding period (which can last for up to 12 h) would reduce the energy expenditure associated with the digestion and assimilation of food (specific dynamic action). Reperfusion during the nonfeeding period would contribute to an unusually high "resting" oxygen uptake. Although some tissues in seals at least can tolerate periods of ischaemia, there is no evidence to suggest that enhanced anaerobic production of ATP is a key factor in the survival of marine mammals during unusually long periods underwater. There may, in fact, be an overall reduction in the ATP requirements of certain tissues, possibly as a result of a reduction in the permeability of cell membranes to some ions, but most certainly as a result of reduced body temperature. During relatively long dives, lactate production eventually exceeds its rate of removal and it accumulates. Precisely what occurs in the muscles is not known. One suggestion is that periods of vasoconstriction are interrupted by vasodilatation, when the oxygen stores are replaced.
Overview of epithelial ion-transport mechanisms
Authors: Shuttleworth Trevor J.
Published: March 2009

The basic cellular transport mechanisms for the transepithelial uptake and elimination of sodium and chloride ions are briefly reviewed. These frequently involve processes defined as secondary active mechanisms, and the problems that this creates for their identification in epithelial systems are emphasised. It is suggested that despite the wide range of epithelial tissues involved in body fluid ion regulation, current evidence indicates that a relatively limited group of these secondary active carriers is involved in the transport process, and the basis for this evolutionary conservatism is discussed, together with certain of its implications. Finally, the interactions of the transport mechanisms with metabolic and acid–base parameters are contrasted in ion-uptake and ion-excretion situations, and the possible roles of carbonic anhydrase compared.
Gill morphometry and fish osmoregulation
Authors: Laurent Pierre , Hebibi Nadra
Published: March 2009

Morphofunctional parameters were studied during adaptation of rainbow trout (Oncorhynchus mykiss) to different ionic environments: Strasbourg tap water, ion-poor water, and artificial seawater. The gill lamellae displayed large changes in size. Surface area of individual lamellae increased in trout acclimated to ion-poor water or seawater. Conversely, the harmonic mean thickness of the lamellar epithelium decreased in seawater, and to an even greater extent in ion-poor water. The apical surface area of individual branchial filament chloride cells, the number of these cells, and their apical surface density per unit of filament epithelial surface area were calculated in these three conditions. These variables did not differ significantly in Strasbourg tap water or seawater, but increased greatly in ion-poor water. These results are discussed in relation to gill permeability and ionic regulation in fish.
Numbers of lungworm larvae in feces of bighorn sheep: yearly changes, influence of host sex, and effects on host survival
Authors: Festa-Bianchet Marco
Published: March 2009

The number of Protostrongylus spp. first-stage larvae in the feces of marked bighorn sheep (Ovis canadensis) was monitored from 1981 to 1988 in southwestern Alberta. Prevalence of infection was 100%. Counts were not correlated with spring precipitation, winter temperature, or number of female sheep in the study population. Percent lamb survival and average counts were correlated only when years affected by the occurrence of a pneumonia epizootic were excluded. In the years before the epizootic, but not afterwards, lambs born to females with high larval counts were less likely to survive to weaning or to 1 year of age than lambs born to females with low counts. Fecal larval counts from the same female in successive years were weakly correlated, and tended to change towards the mean for all females. Counts were affected by host reproduction but not by seasonal migration, and did not affect host survival. Among lambs and yearlings, males had higher counts than females. Lambs had higher counts than adult females. There were no age-specific differences among adult females. The larval count from female lambs was correlated with that from their mother but not that from male lambs. Heart girth of female lambs was correlated with their larval count and that of their mother. I suggest that larval counts are affected by infection intensity and body condition, do not predict pneumonia epizootics, and have limited reliability as an index of herd health.
Effects of nonlethal injury and habitat complexity on predation in tadpole populations
Authors: Figiel Jr. Chester R. , Semlitsch Raymond D.
Published: March 2009

Our purpose was to determine how nonlethal prey injury and habitat complexity mediate the dynamics of a predator–prey system. We assessed rates of predation by the crayfish Procambarus acutus acutus on Hyla chrysoscelis tadpoles with four levels of tail loss (0, 25, 50, and 75% total tail length removed), and in habitats of three levels of complexity (zero, low, and high density of screen) in a 4 × 3 factorial design. We also examined the effects of tail loss on tadpole sprint velocity and distance traveled. Tadpoles with 75% tail loss were preyed upon significantly more often than tadpoles in the other tail-loss treatments. Habitat complexity did not affect tadpole survival. In addition, there was no interaction between tail loss and habitat complexity. Tail loss significantly affected both tadpole swimming velocity and sprint distance traveled. Tadpoles with 75% tail loss had slower sprint speed and swam a shorter distance than tadpoles with 0 and 25% tail loss, and tadpoles with 50% tail loss had slower sprint speed and swam a shorter distance than tadpoles in the 0% tail loss treatment. Although tadpoles generally rely on short bursts of speed, generated by the tail, to escape predators, tail injury and apparently reduced swimming performance did not increase vulnerability to predation in a simple linear fashion.
PLASTIC DEFORMATION BEHAVIOR OF HIGH STRENGTH STEEL SHEET UNDER NON-PROPORTIONAL LOADING AND ITS MODELING
Authors: UEMORI TAKESHI , MITO YUJI , SUMIKAWA SATOSHI , HINO RYUTARO , YOSHIDA FUSAHITO , NAKA TETSUO
Published: March 2009

This paper deals with plastic deformations of a high tensile strength steel sheet (HTSS sheet) under biaxial stress condition including strain path. Using a cruciform specimen of a HTSS sheet of 780MPa-TS, experiments under proportional and non-proportional loadings were investigated. Numerical simulations of stress-strain responses for several strain paths after biaxial stretching were conducted using a large-strain cyclic plasticity model (Yoshida-Uemori model). The results of numerical simulation agrees well the corresponding experimental results, which is attributed to the accurate modeling of the backstress evolution of the anisotropic yield function.
THERMOMECHANICAL RESPONSE OF THE ROTARY FORGED WHA OVER A WIDE RANGE OF STRAIN RATES AND TEMPERATURES
Authors: GUO W. G. , QU C. , LIU F. L.
Published: March 2009

This paper is to understand and model the thermomechanical response of the rotary forged WHA, uniaxial compression and tension tests are performed on cylindrical samples, using a material testing machines and the split Hopkinson bar technique. True strains exceeding 40% are achieved in these tests over the range of strain rates from 0.001/s to about 7,000/s, and at initial temperatures from 77K to 1,073K. The results show: 1) the WHA displays a pronounced changing orientation due to mechanical processing, that is, the material is inhomogeneous along the section; 2) the dynamic strain aging occurs at temperatures over 700K and in a strain rate of 10-3 1/s; 3) failure strains decrease with increasing strain rate under uniaxial tension, it is about 1.2% at a strain rate of 1,000 1/s; and 4) flow stress of WHA strongly depends on temperatures and strain rates. Finally, based on the mechanism of dislocation motion, the parameters of a physically-based model are estimated by the experimental results. A good agreement between the modeling prediction and experiments was obtained.
EVALUATION OF DAMAGE IN STEELS SUBJECTED TO EXPLOITATION LOADING - DESTRUCTIVE AND NON-DESTRUCTIVE METHODS
Authors: KOWALEWSKI ZBIGNIEW L. , MACKIEWICZ SŁAWOMIR , SZELĄŻEK JACEK , PIETRZAK KRYSTYNA , AUGUSTYNIAK BOLESŁAW
Published: March 2009

Damage due to creep and plastic flow is assessed using destructive and non-destructive methods in steels (40HNMA and P91). In the destructive methods the standard tension tests were carried out after prestraining and variations of the selected tension parameters were taken into account for damage identification. In order to assess a damage development during the creep and plastic deformation the tests for both steels were interrupted for a range of the selected strain magnitudes. The ultrasonic and magnetic techniques were used as the non-destructive methods for damage evaluation. The last step of the experimental programme contained microscopic observations. A very promising correlation between parameters of methods for damage development evaluation was achieved. It is well proved for the ultimate tensile stress and birefringence coefficient.
RESEARCH ON THE EFFECT OF LOADING CONDITIONS ON THE STRENGTH AND DEFORMATION BEHAVIORS OF ROCKS
Authors: PAN PENG-ZHI , FENG XIA-TING , ZHOU HUI
Published: March 2009

The paper aims at a numerical study of strength and deformation behaviors of rocks under different loading conditions in uniaxial compression with an elasto-plastic cellular automaton (EPCA2D) code. Two loading conditions, i.e. with and without considering frictions between loading platens and rock specimen's ends, are used in the failure processes of heterogeneous rocks. Rock specimens are assumed to be the same heterogeneity, i.e. the specimens with different sizes have the same probability of containing flaws. Under this condition, it is concluded that the strength and deformation behaviors of rocks are influenced by the heterogeneity a little. The mismatch of elastic properties of the platen and the rock in influencing the stress distribution at the ends of the specimen is the dominant cause for the so-called strength and deformation size effects, which in turn affects the final failure patterns of rocks.
A STUDY ON THE BEHAVIOR OF A THIN STS 304 SHEET WITH A FREE BOUNDARY CONDITIONS SUBJECTED TO IMPACT LOADING
Authors: AHN D. G. , MOON G. J. , JUNG C. G. , YANG D. Y.
Published: March 2009

The objective of this paper is to investigate into impact behaviors of a STS 304 sheet with a thickness of 0.7 mm in a free boundary condition subjected to impact loading by a hemispherical impact head using drop impact tests and the three-dimensional FE analyses. The drop impact tests and the FE analyses were conducted with different impact energy ranging from 37.0 J to 45.7 J. From the results of the impact tests, the influence of the impact energy on the force-deflection curve, the absorption mechanism of the impact energy and deformation behaviors of specimen were examined quantitatively. Through the FE analyses, the variation of stress-strain distributions and characteristics of the local deformation during the impact of the specimen were investigated.
AN EXPERIMENTAL STUDY ON THE IMPACT DEFORMATION AND THE STRAIN RATE SENSITIVITY IN SOME STRUCTURAL ADHESIVES
Authors: NAGAI TOSHIMASA , IWAMOTO TAKESHI , SAWA TOSHIYUKI , SEKIGUCHI YASUHISA , KURAMOTO HIDEAKI , UESUGI NORIO
Published: March 2009

The impact deformation behavior and the strain sensitivity of structural adhesives are experimentally investigated by using INSTRON-type universal testing machine and split Hopkinson pressure bar apparatus. The experimental results show some fundamental features of the typical compressive stress-strain behavior of polymers with linear elastic and nonlinear inelastic deformation stages. In the inelastic deformation, the peak stress, and the strain-softening stage after the peak can be observed at the entire range of strain-rate from 10-4 to 103 /s. In addition, it can be found that the relationship between the peak stress at the strain-softening stage and strain-rate for a semi-logarithm curve is linear in a range of low strain rate, however, that becomes nonlinear at high strain rate. Finally, some constitutive models try to be applied for to describe the stress-strain behavior of structural adhesives.
STUDY FOR BLADE CERAMIC COATING DELAMINATION DETECTION FOR GAS TURBINE
Authors: CHOI CHOUL-JUN , CHOI SEUNG HYUN , KIM JAE-YEOL
Published: March 2009

The component of the hot gas path in gas turbines can survive to very high temperatures because they are protected by ceramic Thermal Barrier Coating (TBC); the failure of such coating can dramatically reduce the component life. A reliable assessment of the Coating integrity and/or an Incipient TBC Damage Detection can help both in optimizing the inspection intervals and in finding the appropriate remedial actions.

This study gives the TBC integrity; so other methods are required, like thermography to obtain indications of TBC delamination. Pulsed Thermography detects coating detachments and interface defects, with a large area of view but a spatial resolution of few mm. The mentioned techniques as a whole constitute a powerful tool for the life assessment of thermal barrier coating.
TENSILE TEST BASED MATERIAL IDENTIFICATION PROGRAM AFDEX/MAT AND ITS APPLICATION TO TWO NEW PRE-HEAT TREATED STEELS AND A CONVENTIONAL Cr-Mo STEEL
Authors: JOUN MAN-SOO , EOM JAE-GUN , LEE MIN-CHEOL , PARK JEONG-HWI , YOON DUK-JAE
Published: March 2009

A material identification program AFDEX/MAT is presented in this paper. The program is based on the method for acquiring true stress-strain curves over large range of strains using engineering stress-strain curves obtained from a tensile test coupled with a finite element analysis. In the method, a tensile test is analyzed using a rigid-plastic finite element method combined with a perfect analysis model for its associated simple bar to provide the information of deformation. An initial reference true stress-strain curve, which predicts the necking point exactly, is modified iteratively to minimize the difference in tensile force between the experiments and predictions of the tensile test. It was applied to identifying the mechanical behaviors of two new pre-heat treated steels of ESW95 and ESW105 and a conventional Cr - Mo steel of SCM435. The predictions are compared with the experiments for the tensile test of the three materials, showing an excellent similarity.
THE DEVELOPMENT OF THE MICROSTRUCTURE AND TEXTURE IN COLD ROLLED AZ31 MG ALLOY SHEETS
Authors: KIM INSOO , AKRAMOV SAIDMUROD
Published: March 2009

Formability is very important parameter of magnesium alloy sheets and it would be related to the texture of sheet metals. In this study, magnesium alloy sheets with strong {0002} texture were cut along the angles of 0, 12.5, 25 and 37.5 degrees to rolling direction (RD). Prepared samples were rolled at room temperature condition. Cold rolled AZ31 magnesium alloy sheets along the angles of 0, 12.5, 25, 37.5 and 45 degrees to rolling direction were investigated microstructure and texture with optical microscopy and x-ray diffractometer, respectively.