bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal distribution, maturity, condition, and feeding of smooth flounder (Pleuronectes putnami) in the Miramichi estuary, southern Gulf of St. Lawrence
Authors: Hanson John Mark , Courtenay Simon C.
Published: April 2008

Smooth flounder, Pleuronectes putnami, were collected by seine, trawl, and sampling of a commercial trap-net fishery in the Miramichi estuary in 1991–1993. Smooth flounder mainly occurred in the upstream half of the estuary during spring and summer but also occupied the lower estuary during late autumn and winter. Small (total length < 10 cm) fish were captured only in nearshore (< 1.5 m deep) waters during summer months but moved to deeper water during autumn. Large fish (> 15 cm long) were found only in the deeper (> 2.5 m) offshore waters. The size at which 50% of fish became sexually mature was 9.6 cm for males compared with 13.5 cm for females (presumed age 1 or older for both sexes). Most smooth flounder spawned during December. Body condition peaked during July, and lowest values were found during February; however, it probably declined further during March (when observations were not possible) because smooth flounder did not feed during winter months. Feeding activity was highest during June and July and declined during October and November, and all stomachs were empty during January and February. The principal prey of smooth flounder > 5 cm long was small bivalves. Very small amounts (never more than 5% of diet by mass) of sand shrimp (Crangon septemspinosa), crabs (Rhithropanopeus harrisi), and polychaetes were also eaten.
Spirocamallanus species of French Polynesian coral reef fishes
Authors: Rigby Mark C. , Adamson Martin L.
Published: April 2008

Spirocamallanus monotaxis is redescribed from Monotaxis grandoculis (Lethrinidae) and reported from 10 other species of coral reef associated fishes from both the Society Islands and the Tuamotu Islands. This represents a new locality for S. monotaxis and 10 new host records. Spirocamallanus colei n.sp. is described from Acanthurus achilles (Acanthuridae) and from Acanthurus guttatus, Acanthurus lineatus, Acanthurus triostegus, and Zebrasoma scopas from both the Society Islands and the Tuamotu Islands. Spirocamallanus chaimha n.sp. is described from Ctenochaetus striatus and Acanthurus olivaceous (Acanthuridae) from Moorea in the Society Islands. The number of buccal capsule ridges in Spirocamallanus varies and minor differences have no taxonomic importance. Marine Spirocamallanus species appear to belong to a single clade characterized by 3 preanal papillae and 5 postanal papillae. This clade may be subdivided on the basis of the shape of the female tail. In French Polynesia, ecological factors as opposed to phylogenetic factors appear to determine host specificity for Spirocamallanus. A new system of reporting the positions of the caudal papillae, based on the position of the papillae relative to the length of the alae, is used.
Seasonal activity and temporal separation of four species of fleas (Insecta: Siphonaptera) infesting Richardson's ground squirrels,Spermophilus richardsonii(Rodentia: Sciuridae), in Manitoba, Canada
Authors: Lindsay L. Robbin , Galloway Terry D.
Published: April 2008

Fleas were collected from Richardson's ground squirrels (Spermophilus richardsonii) livetrapped in two areas in southern Manitoba. Our objectives were to describe the seasonal activity of the fleas and determine whether peaks in mean infestation parameters for different species of fleas occurred at different times of the year. We also wanted to determine if the seasonal activity of Opisocrostis bruneri was different in the presence of other fleas on the same hosts. Activity of Richardson's ground squirrels at both locations was similar to that observed in previous studies in Canada. Opisocrostis bruneri, Oropsylla rupestris, Neopsylla inopina, and Rhadinopsylla fraterna infested ground squirrels near Darlingford, whereas only O. bruneri occurred at two Winnipeg sites. Females of all species outnumbered males during most weekly collection periods. Mean intensity of N. inopina was highest during April, when prevalence of infestation often exceeded 50%. Prevalence of R. fraterna seldom exceeded 10%; there were peaks of infestation on adult squirrels during early April and on juveniles from mid-August to the end of the season. Oropsylla rupestris was the most abundant species on squirrels at Darlingford, and peaks of prevalence and intensity of infestation occurred during April, July, and September. There were two peaks of infestation for O. bruneri, on adult squirrels in May and on juveniles during August. Patterns of activity of O. bruneri were the same for Darlingford and Winnipeg, despite the occurrence of three additional flea species on ground squirrels at Darlingford.
Metabolic depression during dormancy in the African tortoiseKinixys spekii
Authors: Hailey Adrian , Loveridge John P.
Published: April 2008

Two hypotheses may explain the lack of metabolic depression at low temperature in hibernating reptiles from warm but not cool climates. (1) Physiological ability; reptiles from cool climates have resting metabolic rates elevated at low temperatures and so have greater potential for metabolic depression. (2) Energy benefit; hibernation is generally short in warm climates, so the energy saving possible at low temperature is small. These hypotheses can be separated in a warm-climate reptile that hibernates for a long period, such as the African tortoise Kinixys spekii, which is dormant for 7–8 months a year, in winter and in the following hot dry season. Dormant tortoises had a reduced rate of oxygen consumption [Formula: see text] between 10 and 25 °C compared with resting [Formula: see text] measured at the same temperatures in the active season, and at 10–15 °C compared with the resting [Formula: see text] of controls kept active in winter. These data are consistent with hypothesis 2 but not hypothesis 1. The metabolic rate during dormancy was, on average, 59% of resting [Formula: see text], with minimum rates of 47–48% at 10 and 25 °C, similar to the minimum rates of about 50% of resting [Formula: see text] in other hibernating reptiles. Aestivating ectotherms achieve greater metabolic depression, to about 25% of resting [Formula: see text], possibly as a result of reduced gas exchange.
Adult female domesticated canaries can modify their song preferences
Authors: Nagle L. , Kreutzer M. L.
Published: April 2008

Previous research has shown that acoustic experiences in early life influence song preferences in female domesticated canaries, Serinus canaria. We do not know, however, if they can modify song preferences in adulthood. In the experiments reported here, one group of young female domesticated canaries was reared in acoustic isolation in early life without song tutoring, while two groups were tutored with a playback song (one with wild canary song and one with domesticated canary song). We tested these three groups of females once they had reached adulthood, prior to breeding, using copulation-solicitation displays as an index of their song preferences. The females were then placed in an aviary with males during the breeding period, after which they were retested. We observed that the song preferences of females reared in acoustic isolation and those tutored with wild canary song had changed. These females were able to develop new song preferences in adult life. These results are discussed in relation to current views on song preferences and sexual imprinting.
Body mass and survival of bighorn sheep
Authors: Festa-Bianchet Marco , Jorgenson Jon T. , Bérubé Céline H. , Portier Christine , Wishart William D.
Published: April 2008

In ungulates, body mass is often positively correlated with juvenile survival, but little is known of whether body mass affects survival of other age-classes. We studied two marked populations of bighorn sheep (Ovis canadensis) in Alberta, Canada, to determine if body mass affected the survival of different sex –age classes. Chest girth at weaning was correlated (P < 0.0001) with survival of bighorn lambs in the Sheep River population. In the Ram Mountain population, body mass in mid-September had a stronger effect upon survival than mass in early June, mass gain in summer, or mass loss in winter. Body mass at weaning was correlated with lamb survival (P = 0.004). In both study areas, relationships between size and survival of lambs were similar for the two sexes. At Ram Mountain, survival of yearling and adult males seemed to be independent of body mass. Light yearling females were less likely to survive than heavy yearling females. Among females aged 3 – 6 years, body mass had no effect on survival. Among females 7 years of age and older, mass in mid-September had a weak but significant (P = 0.03) effect on survival. Females were slightly lighter in mid-September in their last year of life than in the rest of their adult life. Maternal expenditure is unlikely to affect the survival of prime-age ewes, but may have a detrimental effect on the survival of older ewes.
Spatial differences in macroinvertebrate community structure in springs in southeastern Ontario in relation to their chemical and physical environments
Authors: Williams D. Dudley , Williams Nancy E. , Cao Yong
Published: April 2008

This study examined the benthic macroinvertebrate communities of 20 springs in southeastern Ontario in relation to major water chemical variables and temperature. Significant differences were evident among the spring communities, and a TWINSPAN classification showed three major groups, which were associated with different levels of urbanization and water chemical conditions. Canonical correspondence analysis (CCA) ordinations indicated that the major environmental gradient was related to temperature and NH4 and to two springs adjacent to a landfill site. CCA ordination of a sub-data set excluding these latter two sites together with 3 closely related variables better illustrated the response of spring communities to different levels of urbanization. The strongest relationship to emerge was that between taxon occurrences and chloride, a major contaminant in groundwater in the study area and believed to be derived from road salt. Several taxa were closely associated with high chloride levels (e.g., Tipulidae and Ceratopogonidae), whereas others occurred only in springs with low chloride levels (e.g., Gammarus pseudolimnaeus and Turbellaria). The possibility of using spring macroinvertebrates as biological indicators of chloride contamination of groundwater is discussed.
Terrestrial isopods from Costa Rica and a redescription of Ischioscia variegata (Dollfus, 1893) (Crustacea: Isopoda: Oniscidea)
Authors: Leistikow Andreas
Published: April 2008

Examination of a small collection of Oniscidea from Costa Rica revealed the presence of two species new to science (Ischioscia martinae sp.nov. and Scleropactes talamancensis sp.nov.). Further specimens from the collection of the United States National Museum were reexamined to reconsider the status of Philoscia muscorum (Scopoli, 1793) and Ischioscia variegata (Dollfus, 1893), both of which have been reported from Costa Rica. The specimens belong to two new species (Ischioscia muelleri sp.nov. and Ischioscia elongata sp.nov.). Redescriptions of Ligia baudiniana Milne Edwards, 1840 from the shores of both the Caribbean Sea and the Pacific Ocean and the type material of Ischioscia variegata (Dollfus, 1893) from Venezuela are also presented.
Population structure and the evolution of sexual size dimorphism and sex ratios in an insular population of Florida box turtles (Terrapene Carolina bauri)
Authors: Dodd Jr. C. Kenneth
Published: April 2008

Hypotheses in the chelonian literature suggest that in species with sexual size dimorphism, the smaller sex will mature at a smaller size and a younger age than the larger sex, sex ratios should be biased in favor of the earlier maturing sex, and deviations from a 1:1 sex ratio result from maturation of the smaller sex at a younger age. I tested these hypotheses using data collected from 1991 to 1995 on an insular (Egmont Key) population of Florida box turtles, Terrapene Carolina bauri. Contrary to predictions, the earlier maturing sex (males) grew to larger sizes than the late maturing sex. Males were significantly larger than females in mean carapace length but not mean body mass. Sex ratios were not balanced, favoring the earlier maturing sex (1.6 males: 1 female), but the sex-ratio imbalance did not result from faster maturation of the smaller sex. The imbalance in the sex ratio in Egmont Key's box turtles is not the result of sampling biases; it may result from nest placement. Size-class structure and sex ratios can provide valuable insights into the status and trends of populations of long-lived turtles.
Prey selection by harbour seals, Phoca vitulina, in relation to variations in prey abundance
Authors: Tollit Dominic J. , Thompson Paul M. , Greenstreet Simon P. R.
Published: April 2008

This study compared the composition of the diet of harbour seals (Phoca vitulina) feeding in the Moray Firth, Scotland, with the abundance of their fish prey estimated from dedicated fishery surveys in January 1992 and 1994 and June 1992. Prey-size selection was also examined in these three time periods and in January 1991. In each period, the most abundant fish species contributed most to the diet. However, the relative abundances of the remaining species in the sea showed little similarity to their contribution to the seals' diet. Diet composition was almost totally dominated by either pelagic species or species dwelling on or strongly associated with the seabed, depending upon the relative abundance of pelagic schooling prey. Most fish consumed were 10–16 cm in length, although larger cod and herring were taken. With the exception of cod, the extent of size selection was dependent upon the use of correction factors that accounted for otolith erosion due to digestion.
Effects of fasting and refeeding on body composition of captive gray wolves (Canis lupus)
Authors: Kreeger T. J. , DelGiudice G. D. , Mech L. D.
Published: April 2008

We examined the effects of fasting and refeeding on body composition in 9 captive adult gray wolves, Canis lupus (6 males, 3 females), during May–June 1995. Body composition was estimated by the technique of tritiated water dilution. Wolves were immobilized and weighed, base-line blood samples were taken, tritiated water was injected, and additional blood samples were taken before fasting, after 10 d of fasting, and again after 2 d of refeeding. Male wolves lost 8% (P = 0.0001) and females lost 7% body mass (P = 0.01) during the 10 d. Males lost 54% of this mass in water, 28% in fat, and 18% in protein/ash; females lost 58% in water, 20% in fat, and 22% in protein/ash. Upon refeeding, male wolves consumed an average of 6.8 kg (15.3% body mass) of deer meat per day and females consumed 6.4 kg (18.7% body mass). All wolves regained their initial mass. Males regained 24% of this mass in water, 70% in fat, and 6% in protein/ash; females regained 35% in water, 51% in fat, and 14% in protein/ash. This study provided evidence that after prolonged fasting, captive wolves could quickly and efficiently regain lost body mass after refeeding.
The critical thermal maximum: history and critique
Authors: Lutterschmidt William I. , Hutchison Victor H.
Published: April 2008

We reviewed 725 papers published since Cowles and Bogert's paper on thermal tolerance (R.B. Cowles and C.M. Bogert. 1944. Bull. Am. Mus. Nat. Hist. 83: 261–296) to create a data base of studies that used critical thermal maximum or lethal-temperature methods. We found data from 388 of these papers to provide a historical and taxonomic review of various methodologies used in measuring tolerance of high temperature. We conducted this literature review of previous studies to (i) describe the history of the study of thermal tolerance and show the chronological trends in the use of lethal temperature and critical thermal maximum methods, (ii) illustrate the diversity of taxa used in thermal-tolerance studies, (iii) summarize the diversity of protocols (i.e., end points, heating rates, acclimations, etc.) used for determining thermal tolerance, (iv) provide physiological reasons why the onset of spasms is more meaningful biologically than the loss of righting response, and (v) discuss the difficulties in using data from studies in which widely divergent methods were used and the importance of obtaining comparative thermal-tolerance data for comparative physiology. The adoption of the onset of spasms as a standard end point would allow for valid comparisons of data from different studies and among taxa, an important consideration for current investigations of comparative physiology that use the comparative phylogenetic method.
Space use by polar bears in and around Auyuittuq National Park, Northwest Territories, during the ice-free period
Authors: Ferguson Steven H. , Messier François , Taylor Mitchell K.
Published: April 2008

We investigated patterns of space use by polar bears (Ursus maritimus) in and around Auyuittuq National Park, Northwest Territories, during the ice-free period in 1991–1995, using satellite telemetry and capture locations. Female polar bears showed general fidelity to the region but no site-specific fidelity. The pattern of sea-ice ablation influenced when and where bears were forced to leave the ice for land, usually at the end of August. While awaiting the return of sea ice, bears conserved energy by reducing movement and activity. Bears left the land after ice formed that was strong enough to support them, usually in mid-November. During the ice-free period, females with cubs of the year were farther inland, closer to fjords, and less likely to use islands than were males. Males found close to females with cubs of the year were thinner than the average male, suggesting that segregation may result from the threat of intraspecific predation. Females with cubs of the year left the ice for land earlier than other classes of bears and rarely used snow shelters. After about 1 week on land, pregnant females entered a maternal den for the winter. Unlike those in other polar bear populations, most females with 1-year-olds entered a shelter after about 3 weeks on land and remained there for about 2 months. Dens and shelters were located at high elevations and far from the coast, and sheltering bears weighed more than nonsheltering bears.
Time budgets and synchrony of activities in muskoxen: the influence of sex, age, and season
Authors: Côté Steeve D. , Schaefer James A. , Messier François
Published: April 2008

Synchrony of activities and time budgets of age–sex classes of muskoxen (Ovibos moschatus) was studied on Victoria Island in the Canadian High Arctic during late winter (April – late May), spring (late May – early June) and summer (mid-June – July). As revealed by the kappa (κ) coefficient of agreement, herd members exhibited significant synchrony in 79 of 82 groups. The degree of synchrony was not related to group size in mixed herds but decreased with group size in bachelor herds. Diversity in age–sex classes, group type (mixed versus bachelor), and season did not affect synchrony. However, synchrony was less among adult males than among other age–sex classes. Muskoxen were more synchronised at the start of activity bouts than at the end. As revealed by principal components analysis, calves tended to spend more time lying and standing and less time feeding than other age–sex classes. In addition, males in bachelor groups tended to feed more and rest less than males in mixed herds. Duration of active and lying bouts was not affected by age–sex class. Length of active bouts did not change with season, but lying bouts decreased in length significantly from late winter to spring and from spring to summer. We suggest that synchrony of activities maintains group cohesion but constrains the time budget of some group members, especially adult males.
The effect of cover and food on space use by wintering Song Sparrows and Field Sparrows
Authors: Beck Christopher W. , Watts Bryan D.
Published: April 2008

The distribution of birds among microhabitats may reflect species-specific resource requirements. Both food availability and predation risk have been shown to influence patterns of microhabitat use by sparrows during winter. We investigated the influence of vegetative cover and food on microhabitat use using a 2 × 2 factorial design. Both woody cover and food were manipulated at the plot level. The presence of screening cover (weed stems) was manipulated within plots. Sparrows showed a positive response to the presence of both cover and food. Within plots, sparrows selected areas with screening cover. The distribution of birds between areas with and without screening cover was influenced by the presence of woody cover and food. Conversely, the presence of screening cover reduced the influence of woody cover on the distribution of birds within patches. Song Sparrows (Melospiza melodia) and Field Sparrows (Spizella pusilla) differed in their response to treatments both within and across plots, suggesting that trade-offs between foraging and predation risk may be important in the structuring of winter sparrow assemblages. Additionally, screening cover appears to moderate predation risk and therefore to affect distribution patterns.
Black bears as ant-eaters: seasonal associations between bear myrmecophagy and ant ecology in north-central Minnesota
Authors: Noyce Karen V. , Kannowski Paul B. , Riggs Michael R.
Published: April 2008

We documented the seasonal occurrence and volume of different ant species in black bear (Ursus americanus) scats in north-central Minnesota. We determined nest densities of common ant species in strip transects and compared their use by bears with their availability. We recorded phenologic change in ant-nest characteristics and measured the nutritional composition of ant workers, ant pupae, and herbaceous spring foods of bears. Consumption of ants was higher than reported elsewhere, peaking in early July, when ants constituted 58% of scat volume and occurred in 96% of scats. Increased consumption of ants in late spring coincided with (i) increased abundance and size of ant brood in nests and (ii) decreased protein and increased fiber levels in herbaceous foods. Lasius umbratus was the principal species consumed at 1 site, whereas L. umbratus, Acanthomyops interjectus, and A. claviger dominated the diet farther south. These ants were likely preferred to other equally abundant species because of their sometimes dense concentrations inside nests, passive behavior, and distinctive odor, enabling bears to forage more efficiently than on other species. We suspect that regional differences in ant consumption are due to differences in local availability of these species. Where they are less common, bears likely select large-bodied ants, usually Camponotus and Formica species.
Seasonal variation in body composition and gut capacity of the prairie vole (Microtus ochrogaster)
Authors: Voltura Mary Beth
Published: April 2008

Prairie voles (Microtus ochrogaster) were trapped during different seasons in order to examine simultaneous variation in body composition and gut capacity. Voles in reproductive condition were trapped in May, August, and November but not in February. Body masses of adult voles were lowest during February 1994. Adult males showed no seasonal variation in absolute lipid mass but did exhibit variation in relative fat content (percent body fat), with the highest values found in February 1994. Both absolute lipid mass and relative fat content of adult females varied with month of capture and were higher in February of both 1994 and 1995. Juvenile voles showed no variation in body composition between seasons and had fat levels similar to those of adult voles in the breeding months. Wet mass of the gastrointestinal tract varied with season of capture for both adult males and females, but no distinct pattern was evident. Mass of gut contents varied between trapping periods for adult males, but there were no seasonal differences in the gut contents of adult females or juveniles. The average mass of gut contents was higher than previously reported for field-caught prairie voles; this difference is likely due to the use of snap traps versus live traps.
Preservation of blood and tissue samples for stable-carbon and stable-nitrogen isotope analysis
Authors: Hobson Keith A. , Gloutney Mark L. , Gibbs H. Lisle
Published: April 2008

Researchers engaged in collecting animal material for stable-carbon and stable-nitrogen isotope analysis are frequently faced with the need to preserve tissues prior to transportation to the laboratory. In many cases, freezing is not possible in the field, so we investigated the potential of several techniques for preserving tissues for this purpose. We also included preservation techniques used for DNA analyses in order to evaluate how they might alter δ13C and δ15N values in tissues and, ultimately, whether archived DNA samples could be used for stable-isotope assay. Tissues included blood and pectoral muscle from quail (Coturnix coturnix japonica) and blood from sheep (Ovis aries). Preservation techniques for blood included freeze-drying (control), drying on precombusted glass-fibre filter paper, and storing in 70% ethanol, 10% buffered formalin, ABI lysis buffer, and Queen's lysis buffer. After 8 weeks, the use of both lysis buffers and formalin resulted in significant depletion of 13C and 15N in blood. Values for samples dried on glass-fibre filter paper or stored in 70% ethanol did not differ significantly from those for the control. Muscle tissue was freeze-dried (control) or stored in 70% ethanol, 10% buffered formalin, or DMSO solution. Both the DMSO and formalin treatments resulted in significant depletion of 13C and 15N compared with the control. Only the 70% ethanol treatment did not result in changes to either isotope ratio in muscle. Where freezing is not possible, we recommend that blood samples be dried or stored in 70% ethanol. Our study provides an estimate of isotopic correction factors that may be applied to tissues archived for DNA analysis or stored in formalin.
Effects of concanavalin A on limb regeneration in the axolotlAmbystoma mexicanum
Authors: Scadding Steven R.
Published: April 2008

The purpose of this investigation was to determine the effects, if any, of concanavalin A (Con A) on the process of pattern formation during limb regeneration in the axolotl Ambystoma mexicanum. Con A was administered to regenerating axolotl forelimbs in a Hydron disk that released the Con A slowly over a period of time. The results indicate that Con A is teratogenic to the regenerating axolotl limb, causing reductions in the number, size, and quality of skeletal elements present, with increasing reductions and malformations as the dose is increased. Low doses resulted in a reduction in the number of carpals or phalanges. Higher doses resulted in more drastic malformations, including the absence of digits. The implications of this teratogenic effect of Con A on limb regeneration are discussed in the context of the possible mechanisms of pattern formation.
Infection strategies of retroviruses and social grouping of domestic cats
Authors: Fromont Emmanuelle , Courchamp Franck , Pontier Dominique , Artois Marc
Published: April 2008

It is thought that parasites may exert selective pressure on the social structure of host populations. We compared the impact of feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV), two retroviruses commonly found in domestic cats (Felis catus). Because of low transmissibility and virulence, both infections have a worldwide distribution and low prevalence. Transmission modes differ: FIV is transmitted only through biting, while FeLV transmission occurs by biting, licking, grooming, and sharing food and from mother to fetus. FeLV is also more pathogenic than FIV. We compared FIV and FeLV prevalence and risk factors within five populations of cats. FIV infection occurred almost exclusively among adult male cats fighting to acquire and maintain dominant status. Classes at risk for FeLV infection included sexually intact cats allowed to roam freely. The impact of FeLV on host population growth was greater than that of FIV but varied among populations. Our results show that FIV is favoured by individual aggressiveness and a hierarchical social system, while FeLV is more prevalent among socially active cats. FeLV may constitute a source of selective pressure against numerous amicable contacts, particularly in urban cat populations, where aggression among individuals is reduced.
A behavioral study of refraction, corneal curvature, and accommodation in raptor eyes
Authors: Glasser Adrian , Pardue Machelle T. , Andison Margot E. , Sivak Jacob G.
Published: April 2008

Since there is much speculation in the literature regarding the accommodative abilities of raptors, we undertook a behavioral study of accommodation in the five families of raptors. The resting refractive state and amplitude of accommodation were measured using infrared video photorefraction in a variety of wild-caught and captive-bred raptors. The resting corneal curvature and the extent of changes in corneal curvature during accommodation (corneal accommodation) were measured using video keratometry. External ocular and head dimensions were measured with calipers to look for correlates with accommodative amplitude. In general, all eyes examined were of high optical quality and relatively free of aberrations. No significant refractive errors were recorded in any of the birds examined (< 1.0 diopters (D)). In general, significant amplitudes of accommodation were measured in the hawks (up to 25.0 D), but little accommodation was seen in the owls. Corneal accommodation ranging from 2.8 to 6.2 D in magnitude was recorded in a number of the hawks. These differences in the accommodative behaviors of the owls and hawks are discussed with respect to the limitations of the behavioral techniques used, differences in the degree of cooperation of the different species, and real differences in the accommodative abilities of the owls and hawks in relation to their accommodative needs, such as when feeding.
Diving patterns of harbour seals (Phoca vitulina) in the Wadden Sea, the Netherlands and Germany, as indicated by VHF telemetry
Authors: Ries Edith H. , Paffen Petra , Traut Ilona M. , Goedhart Paul W.
Published: April 2008

The diving behaviour of 25 harbour seals, Phoca vitulina (14 females and 11 males), of various body lengths was monitored by means of VHF telemetry at different locations in the Wadden Sea during late autumn in 1991 and 1992. Median dive durations for individual seals ranged from 46 s to 2.9 min. The maximum dive recorded was 31 min, performed by an adult male, which represents the longest dive reported for harbour seals. Dive endurance increased significantly in relation to body length. Female harbour seals tended to perform fewer short dives and had a more narrow distribution of dive times. We detected no diurnal differences in dive behaviour and only the ambient air temperature was found to influence the duration of surface periods, in that surface intervals tended to be shorter when temperatures were below 9 °C. The overall mean percentage of dive time was 85%, with individuals varying from 76 to 93%, and was in general higher in females.
Heterospecific attraction affects community structure and migrant abundances in northern breeding bird communities
Authors: Mönkkönen Mikko , Helle Pekka , Niemi Gerald J. , Montgomery Kent
Published: April 2008

We experimentally tested the heterospecific attraction hypothesis by manipulating densities of resident birds (black-capped chickadee, Parus atricapillus, red-breasted nuthatch, Sitta canadensis, and white-breasted nuthatch, S. carolinensis) on 7 lake islands in northern Minnesota, U.S.A. Resident numbers were increased by winter feeding and decreased by removals using mist nets. The heterospecific attraction hypothesis states that migrants use residents as a cue to identify the best sites for breeding in a heterogeneous landscape because residents have already selected higher quality sites. The hypothesis predicts that there will be a higher overall density of migrants associated with increased resident density. Results showed that there was a consistent change in migrant bird community structure (i.e., in the relative abundance of species) in response to manipulation. This change resulted mainly from an increased density of arboreal insectivores, i.e., species that belong to the same foraging guild as residents, suggesting that food is an important factor contributing to heterospecific attraction. The red-eyed vireo, Vireo olivaceus, and black-and-white warbler, Mniotilta varia, showed the strongest positive response. No migrant species responded negatively to augmented resident density, suggesting that interspecific competition may be less important in structuring breeding bird communities in northern forests. Our results support the view that positive interactions should be considered when studying community structure.
Diet of northwest Atlantic harp seals (Phoca groenlandica) in offshore areas
Authors: Lawson John W. , Stenson Garry B.
Published: April 2008

The offshore diet of harp seals (Phoca groenlandica) in the northwest Atlantic was determined by reconstructing the contents of prey-containing stomachs (399 of 724) recovered during 1980–1995. The importance of prey species varied seasonally and geographically. Pups (< 6 months old) usually consumed invertebrates, capelin (Mallotus villosus), and sand lance (Ammodytes dubius). Subadults (6 months to 4 years old) consumed capelin and Arctic cod (Boreogadus saida) in the northern part of their range but sand lance and capelin on the Grand Banks. Adults consumed invertebrates such as shrimp (Pandalus sp.) and Natantia (amphipods) when they were collected on the northern Labrador Shelf, but ate capelin, Greenland halibut (Reinhardtius hippoglossoides), and Atlantic cod (Gadus morhua) on the southern Labrador Shelf. On the Grand Banks they consumed pleuronectids, sand lance, and capelin. Atlantic cod were rarely eaten by seals not caught by commercial trawlers. In contrast to the seals' nearshore diet, capelin were the principal prey on the Grand Banks and Labrador Shelf. Sand lance and Greenland halibut were also important. The contrast between near- and off-shore diets illustrates the importance of geographical variation in the contribution of a single prey species to the diet, especially in attempts to extrapolate consumption of specific prey.
Thread trailing of turtles: methods for evaluating spatial movements and pathway structure
Authors: Claussen Dennis L. , Finkler Michael S. , Smith Meghan M.
Published: April 2008

Although many authors have used thread trailing to monitor movements of turtles and other vertebrates, most have evaluated only a portion of the information contained in these pathways. We describe ways of extracting information from thread trails by determining length of trail, mean distance moved per unit time, net displacement, area encompassed by the trail, mean turning angle, and mean vector length. We further describe and compare four measures of trail sinuosity, the ratio of greatest distance to length of path (d/L), the square root of the ratio of area to path length [Formula: see text], fractal dimension (D), and sinuosity (S); we then applied these methods to the trails of a population of ornate box turtles (Terrapene ornata) from the Nebraska Sand Hills. Though preliminary, these data suggest that vegetation cover affects the sinuosity of turtle trails (based on D), that temperature affects the mean distance moved per day, that T. ornata ordinarily show little or no directional bias, and that injury can affect distance moved, trail sinuosity, and mean turning angle. Among these measures of trail sinuosity, D and S are highly correlated and provide similar information. Though less closely correlated with D and S, or with each other, [Formula: see text] and d/L also reflect trail sinuosity; of these indices, however, d/L best reflects trail directionality. This analysis suggests that a more comprehensive evaluation of pathways at this fine scale will provide new insights into the routine movements of animals.
Whole-body urea cycling and protein turnover during hyperphagia and dormancy in growing bears (Ursus americanusandU.arctos)
Authors: Barboza Perry S. , Farley Sean D. , Robbins Charles T.
Published: April 2008

Subadult bears were studied during their autumn hyperphagia (n = 3) and winter dormancy (n = 6). Urea kinetics were measured with14C- and15N-urea, protein turnover was estimated with15N-glycine, and body composition was assessed with3H-water. Reduced amino acid degradation in winter was indicated by declines in plasma urea and aminotransferase activities, and lower urea production than in autumn (4.7 vs. 27.5 mmol urea-N∙kg−0.75∙d−1). Only 7.5% of urea produced in hyperphagic bears was degraded and just 1.1% of the degraded N reutilized as amino-N. Dormant bears reutilized 99.7% of urea produced, indicating thorough microbial ureolysis and urea-N resorption. Low rates of body N loss during dormancy suggested losses of non-urea N as creatinine. Protein turnover rates (15.2–21.5 g∙kg−0.75∙d−1) were similar between seasons and reflected the apparent maintenance of hepatic, intestinal, and muscular functions through dormancy. Protein synthesis accounted for 32% of energy expended in dormancy, which was mainly (91.5%) derived from fat oxidation. Consistent organ function and body temperature in dormant bears enables recycling of urea-N, which minimizes body protein loss and conserves mobility. In comparison with heterothermic hibernation, ursid dormancy would provide greater flexibility during winter and facilitate rapid resumption of foraging and growth in spring.
RESEARCH OF NESTED PARALLEL PIPELINES ON PARALLEL GRAPHICS RENDERING SYSTEM
Authors: PENG HAOYU , XIONG HUA , LIU ZHEN , SHI JIAOYING
Published: April 2008

Existing parallel graphics rendering systems only support single level parallel rendering pipeline. This paper presents a novel high performance parallel graphics rendering architecture on PC-Cluster supporting tiled display wall. It employs a hybrid sort-first and sort-last architecture based on a new rendering and scheduling structure, called dynamic rendering team (DRT as abbreviation), which is composed of multiple PCs instead of single PC to act as a rendering node. Each DRT responds for a certain projector area in the tiled display wall and all DRTs form a outer level parallel rendering pipeline natively. Inside separate DRT there is an optimized parallel Rendering-Composing-Display (R-C-D) pipeline reconstructing the serial workflow to parallel one. The Optimized parallel R-C-D pipeline along with the outer parallel rendering pipelines among DRTs forms a special nested parallel pipeline architecture, which promotes the whole rendering performance of our system greatly. Experiments show that parallel rendering system with the proposed architecture and nested parallel rendering pipelines, called Parallel-SG, can render over 13M triangles at an average speed of 12 frames per second without any accelerating technologies on a tile-display wall of 5*3 projectors array.
HARDWARE-ACCELERATED PARALLEL-SPLIT SHADOW MAPS
Authors: ZHANG FAN , SUN HANQIU , XU LEILEI , LEE KITLUN
Published: April 2008

Shadow mapping is well known for its generality and efficiency, thus it has been extensively employed for real-time shadow rendering in diverse applications. However, it suffers from inherent aliasing problem due to its image-based nature. In this paper, we present the parallel-split shadow maps scheme which produces high-quality shadows especially in large-scale and complex scenes. Our scheme splits the view frustum into parts using planes parallel to the view plane, and then generates a shadow map for each part. A fast and robust splitting strategy based on the analysis of shadow-map aliasing is proposed, which results in a moderate aliasing distribution over the depth range. Hardware-accelerated processing is developed to eliminate extra rendering passes which surpass that of standard shadow mapping when synthesizing scene-shadows.
REACTION-DIFFUSION BASED DEFORMABLE OBJECT SIMULATION
Authors: ZHONG YONGMIN , SHIRINZADEH BIJAN , SMITH JULIAN
Published: April 2008

This paper presents a new methodology to simulate soft object deformation by drawing an analogy between reaction-diffusion and elastic deformation. The potential energy stored in an elastic body as a result of a deformation caused by an external force is propagated among mass points by the principle of reaction-diffusion. An improved reaction-diffusion model is developed to propagate the energy generated by the external force. A three-layer cellular neural network is established to solve the reaction-diffusion model for real-time simulation of soft object deformation. A material flux based method is presented to derive internal forces from the potential energy distribution established by the reaction-diffusion model. The proposed methodology not only accommodates isotropic, anisotropic and inhomogeneous deformations by simple modification of diffusion coefficients, but it also accepts large-range deformations.
INTUITIVE PARAMETERIZED INPUT INTERFACE FOR PROPORTIONAL RESHAPING OF HUMAN BODIES
Authors: SCHERFF PHILLIP-CHRISTOPH , BACIU GEORGE , HU JINLIAN
Published: April 2008

In the computer world garment products need to be simulated on different virtual human bodies. In this paper we are going to change virtual human actors in a proportional way. As part of the work we design a user-friendly interface for a more intuitive input of body parameters. Curves, implemented as NURBS, create an effective/easy input method for the proportional reshaping task. Implementation of an automatic approach for computing an underlying skeleton was done, which enables us to reshape a virtual human. As body proportions are difficult to define, this paper researches on artistic methods to describe the symmetric and harmonious structures of human bodies. A flexible data structure is employed in order to traverse and access regional information efficiently. As a main goal of this work we designed a high level controller for body parts enabling proportional reshaping.
EXTRACTION OF NOISE TOLERANT, GRAY-SCALE TRANSFORM AND ROTATION INVARIANT FEATURES FOR TEXTURE SEGMENTATION USING WAVELET FRAMES
Authors: ACHARYYA MAUSUMI , KUNDU MALAY K.
Published: April 2008

In this paper, we propose a texture feature extraction scheme at multiple scales and discuss the issues of rotation and gray-scale transform invariance as well as noise tolerance of a texture analysis system. The nonseparable discrete wavelet frame analysis is employed which gives an overcomplete wavelet decomposition of the image. The texture is decomposed into a set of frequency channels by a circularly symmetric wavelet filter, which in essence gives a measure of edge magnitudes of the texture at different scales. The texture is characterized by local energies over small overlapping windows around each pixel at different scales. The features so extracted are used for the purpose of multi-texture segmentation. A simple clustering algorithm is applied to this signature to achieve the desired segmentation. The performance of the segmentation algorithm is evaluated through extensive testing over various types of test images.
MONO-COMPONENTS VS IMFs IN SIGNAL DECOMPOSITION
Authors: QIAN TAO , ZHANG LIMING , LI HONG
Published: April 2008

The concepts of intrinsic mode functions and mono-components are investigated in relation to the empirical mode decomposition. Mono-components are defined to be the functions for which non-negative analytic instantaneous frequency is well defined. We show that a great variety of functions are mono-components based on which adaptive decomposition of signals are theoretically possible. We justify the role of empirical mode decomposition in signal decomposition in relation to mono-components.
FRAME-BASED IMAGE DENOISING USING HIDDEN MARKOV MODEL
Authors: YANG XIAOYUAN , ZHANG XUDONG , ZHU ZHIPIN
Published: April 2008

Wavelet-domain hidden Markov models (HMMs), and in particular, hidden Markov tree (HMT), have been recently proposed and applied to image denoising. In this paper, we present the hidden Markov model and corresponding algorithm based on frame-domain. This model can effectively capture the correlation of wavelet frame coefficients, and we apply this model for image denoising. Furthermore, two new algorithms are developed for denoising. We demonstrate the performance of our new method on some text images with very encouraging results.
FUSION FRAMES AND g-FRAMES IN HILBERT C*-MODULES
Authors: KHOSRAVI AMIR , KHOSRAVI BEHROOZ
Published: April 2008

The notion of frame has some generalizations such as frames of subspaces, fusion frames and g-frames. In this paper, we introduce fusion frames and g-frames in Hilbert C*-modules and we show that they share many useful properties with their corresponding notions in Hilbert space. We also generalize a perturbation result in frame theory to g-frames in Hilbert spaces. We also show that tensor product of fusion frames (g-frames) is a fusion frame (g-frame) and tensor product of resolution of identity is a resolution of identity.
APPLICABILITY OF HOMOGENEOUS HUMAN TRUNK PHANTOM IN ESTIMATING THE RADIATION CHARACTERISTICS OF BODY-WORN DEVICES
Authors: XU LISHENG , MENG MAX Q.-H. , REN HONGLIANG
Published: April 2008

In this paper, the radiation characteristics with respect to the suitability of using homogeneous phantom for testing the compliance of radiation frequency devices are assessed. The Finite-Difference Time-Domain (FDTD) method is applied to analyze the variations of a 900 MHz half-wavelength dipole antenna's biological effects and link performance depending on distance between antenna and human body model. The distance between the surface of the model and the outside exposure source is changed from 25 mm to 1 mm within the range of λ/2π. The distributions of the specific absorption rates (SARs) and the electric fields for various vertical slices of a simplified homogeneous phantom and three anatomical human body trunk models are calculated, respectively. The legs and head have little influence on the radiation characteristics of body-worn, ingestible or implantable wireless devices. The results demonstrate that a homogenous representation of human body is suited for assessing the averaged SARs in human body and confirm that the local energy absorption details and communication link performance need to be analyzed by using the anatomical models or by combining with the worst-case consideration.
A noniterative equivalent waveform model for timing analysis in presence of crosstalk
Authors: Muchherla Kishore Kumar , Chen Pinhong , Ma Dongsheng , Wang Janet Meiling
Published: April 2008

Due to the nonuniform interconnect scaling in the Deep Sub Micron (DSM) region, the coupling capacitance between wires becomes an increasingly dominant fraction of the total wire capacitance. This couple capacitance introduces server crosstalk which causes delay variations on signal lines and raises signal integrity problems. Therefore, including crosstalk in the timing analysis methods has become imperative for current technologies. And to correctly model the crosstalk, output loading effects, waveform shape and gate driving capability have to be considered. However, most existing crosstalk models have not yet included these factors and consequently suffer from the low accuracy problem. In this article, we propose a noniterative equivalent waveform model that addresses the above mentioned issues. Our experimental results have shown that the new model achieves 3 times speed up and 95% accuracy compared to the existing models.