bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and Installation of Light Weight, Low Cost Unbonded Flexible Pipe for Arctic Applications
Authors: Loper Cobie W. , Eck Dan , Fraser Dana , Huvar Bill
Published: March 2009

Unbonded flexible pipe has been successfully operating in oil/gas production applications on the North Slope of Alaska since 1995 as documented in OMAE 1995 paper “Arctic Applications of Flexible Pipe for Production Pipelines and Infield Fluid Transport Systems”, Reference [1]. The pipe and end terminations were subjected to extensive material and full scale testing to confirm suitability for arctic applications and the results are documented in the paper. The products deployed on the tundra were designed to ensure successful, safe operation and mitigate risk for the initial application. The robust design included pipe layers and end fitting materials that exceeded fit for purpose needs and resulted in a heavier, more costly design than was actually needed. To ensure cost effective solutions are available for future projects in the regions, Wellstream in conjunction with the Prudhoe Bay Operating Unit developed an optimized flexible pipe that met the onerous requirements of arctic applications. Pipe specifications included 5.5-inch ID, 3600psi design pressure, thermal loss and cooldown limitations, maximum operating temperature of 140°F and minimum operating temperature of −50°F. This paper will present the results of the design, engineering and analytical process, full scale testing and installation activities. A detailed comparison between the initial products and the current optimized design is presented to illustrate the substantial weight and cost savings achieved.
Assessment of Geometry Correction Functions of Tanker Knuckle Details Based on Fatigue Tests and Finite Element Analysis
Authors: Garbatov Y. , Rudan S. , Soares C. Guedes
Published: March 2009

The paper analyses the fatigue crack growth of knuckle detail typical of tankers. An approach for evaluation of the fatigue life based on fracture mechanics is presented, where a Paris-Erdogan crack-growth law is applied. A geometry correction function is determined from fatigue test data. A closed-form equation is proposed for fatigue life estimation. The results obtained from a fatigue test and the calculated fatigue lives are compared.
Statistics of Wave Crests From Models vs. Measurements
Authors: Prevosto Marc , Forristall Geoerge Z.
Published: March 2009

The analysis phase of the Wave Crest Sensor Intercomparison Study (WACSIS) focussed on the interpretation of the wave data collected by the project during the winter of 1997–98. Many aspects of wave statistics have been studied, but the main emphasis has been on crest height distributions, and recommendations for crest heights to be used in air gap calculations. In this paper we first describe comparisons of the crest height distributions derived from the sensors (radars, wave staffs, laser) and from simulations based on 3D second order irregular wave models. These comparisons permit us to make conclusions on the quality of these models and to qualify the ability of some sensors to measure the crest heights accurately. In the second part two new parametric models of the crest height distributions are discussed and their superiority to standard parametric models is demonstrated.
A Quantitative Integrity and Risk Assessment Approach for Maintenance Planning in Gas Transmission Pipelines
Authors: Martinez Gonzalez Jose L. , Urencio Castro Claudio F. , Betancourt Enrique Rodriguez
Published: March 2009

PEMEX Gas (PGPB) operates a pipeline network of more than 11,000 kilometres that includes natural gas and LPG throughout Mexico and has implemented a risk management program that has been successfully used over the past two years, applying risk assessment software tools to assist its risk management stage. During the past four years PGPB has significantly reduced their pipeline incident rate and have thus lessened their costs in terms of reduced business interruption, environmental and property damages, and safety to the public and PGPB employees. On the same basis, PGPB has increased their pipeline informational databases as they relate to operations, maintenance, construction, and design for their pipeline systems. This approach provides a quantitative means to balance the cost to preserve the pipeline assets against the added value measured in terms of pipeline risk reduction measured in terms of cost of risk. Furthermore, provides information that can be use to make value-based maintenance or operating decisions to promote continued long-term safe operation in a setting that evaluates risk reduction in terms of business interruption, environmental and property damage, and public and employee safety.
Extended GDQ and Related Discrete Element Analysis Methods for Transient Offshore Mechanics and Engineering Problems
Authors: Chen Chang-New
Published: March 2009

The extended GDQ proposed by the author is used to develop solution algorithms for solving the discrete transient equation system of an offshore mechanics or arctic engineering problem. It is a direct integration approach. Two integration methods are developed. They are time-element by time-element method and stages by stages method. These two time integration algorithms can be used to solve generic discrete transient equation system of an originally discrete system or a discrete system resulting from the discretization of a transient system of offshore mechanics and arctic problems by using a certain discretization technique such as the DQEM, FEM, FDM,…, etc.
Limiting Forms of Internal Solitary Waves
Authors: Maltseva Janna L.
Published: March 2009

High sensitivity of nonlinear wave structures in the weakly stratified fluid with respect to small perturbations of density in the upstream flow was pointed out in the paper (Benney & Ko, 1978). In present paper the influence of fine structure of stratification on one of the limiting forms, namely plateau-shaped solitary waves is analyzed. It is demonstrated that new limiting forms of solitary waves are possible in the case of continuous stratification close to linear or exponential one.
A Perfectly Transparent Spectral Shell for Unsteady Wave-Body Interactions
Authors: Hamilton J. Andrew , Yeung Ronald W.
Published: March 2009

A general outer boundary condition for time-dependent wave-body interaction problems is developed. The technique is based on domain decomposition and the unsteady free-surface Green function solution of the flow in an outer region. The boundary condition results in a shell condition which may be applied to a variety of interior solution methods. When the interior solution method is a boundaryintegral method, an implicit matching can be done. When a volume-discretization method is used in the interior region, a newly developed explicit matching procedure is performed. Demonstrations of the transparent properties of this shell are made for several unsteady problems.
Predicting Ice Jams With Neural Networks
Authors: Massie Darrell D. , White Kathleen D. , Daly Steven F. , McDonald Regan
Published: March 2009

One of the most difficult problems facing hydraulicians is the development of a method that predicts the formation of breakup ice jams. Because of the suddenness with which breakup jams and related flooding occur, prediction methods are desirable to provide early warning and allow rapid, effective ice jam mitigation. Breakup ice jam prediction models are presently limited due to the lack of an analytical description of the complex physical processes, and range from empirical single-variable threshold-type analyses to statistical methods such as logistic regression and discriminant function analysis. In this study, a neural network method is used to predict breakup ice jams at Oil City, PA. Discussion of how the neural network input vector was determined and the methods used to appropriately account for the relatively low occurrence of jams are addressed. The neural network prediction proved to be more accurate than other methods attempted at this site.
Anti-Plane Moving Crack in Functionally Graded Piezoelectric Materials
Authors: Jin Bo
Published: March 2009

This paper considers the anti-plane moving crack in functionally graded piezoelectric materials (FGPM). The governing equations for FGPM are solved by means of Fourier cosine transform. The mathematical formulation for the permeable crack condition is derived as a system of dual integral equations. By appropriate transformations, it is shown that the dual integral equations can be reduced to a Fredholm integral equation of the second kind. The results obtained indicate that the stress intensity factor of moving crack in FGPM depends only on the mechanical loading. The gradient parameter of the FGPM and the moving velocity of the crack do have significant influence on the dynamic stress intensity factor.
Green Sea and Water Impact on FPSO: Numerical Predictions Validated Against Model Tests
Authors: Stansberg C. T. , Hellan O̸. , Hoff J. R. , Moe V.
Published: March 2009

A recently developed numerical design method for analysis of green sea events and resulting impact loads on deck structures of FPSO’s, is validated against model test data. Steep irregular wave conditions are considered, and numerical time series reconstructions are made using the measured wave as input. A second-order numerical random wave description is combined with standard 3D wave diffraction and related vessel motions to predict the relative wave kinematics. A modified shallow water formulation is applied for the prediction of the propagation on deck, and resulting local pressures on the deck-house are estimated by a similarity solution. From this an analysis of the structural integrity can be made. Comparisons to the experiments are made for the relative wave amplitudes, water propagation on deck, and the resulting deck-house loads. A reasonably good agreement is observed for the reconstructions, in a statistical sense, but also for individual events. Thus selected green sea events are investigated in detail, and characteristics identified. The agreement with the model tests is promising especially on the background of the simplified approach used, as well as the expected statistical scatter.
Numerical and Experimental Analysis of Extreme Slamming Loads on FPSO Bows
Authors: Hermundstad Ole A. , Stansberg Carl T. , Hellan O̸yvind
Published: March 2009

A practical method for prediction of slamming loads and structural responses in the bow of an FPSO is presented. Incoming waves are simulated by a second-order random wave model, which describes the water elevation and kinematics. Vessel motions are calculated by linear analysis. The diffracted wave field is calculated taking into account linear 3D diffraction. Relative motions are then estimated by combining the linear vessel motions, second-order incoming waves and linear diffraction. The relative motions and velocities at the bow are used as input to numerical slamming calculations. The bow is divided into 2D sections and a boundary value problem is solved for each section applying the generalized Wagner-method of Zhao & Faltinsen (1993) and Zhao et al (1996). The 2D slamming calculations account for the local pile-up of water on each side of the section during impact. Structural responses are calculated from a finite-element model of the bow using the exact pressure distribution from the slamming calculations. This is achieved by automatic mapping of pressures onto the outer surface of the FE-model and performing a quasi-static structural analysis for each time-step. The methods are implemented into a package of computer tools, allowing the user to perform the various steps in the process with little manual editing of data. The system runs easily on a standard PC. Measurements on a 1:55 scaled model of an FPSO are used for validation of the bow slamming calculations. The model was equipped with five 3.85m × 1.65m (full-scale) panels in the upper part of the bow for slamming force measurements. The tests were run in storm conditions with steep waves. The calculated slamming force on a panel located at the foremost tip of the bulwark, 12.8 meters above the mean waterline, is compared with measured results for selected extreme slamming events. Considering the complexity of this problem and the relative simplicity of the approach, the agreement is very good.
Strength of Process Pipes Subjected to Jet Fire
Authors: Czujko Jerzy , Kristensen Odd , Xu Jun
Published: March 2009

This paper presents the application of different analytical methods to determine critical temperature-pressure conditions for the burst of typical pipes used in offshore process plants. The applications of a dynamic non-linear Finite Element method and a simplified analytical method are presented and compared. The application of the Finite Element method is based on the Arbitrary Lagrangian Eulerian (ALE) formulation allowing for the simultaneous simulation of pipe burst and hydrocarbon gas flow to the environment. Numerical predictions are compared with available experiments. The paper also presents the behaviour of pipes after burst with the following impact on neighbouring pipes. The study covers impact between large pipes as well as impact between large and small pipes. Due to impact between pipes, the impacted pipes can collapse, disintegrate and in some cases become projectiles. Impact forces between pipes, together with impact energies are calculated for typical process pipe sizes and materials. Effects of different boundary conditions for pipes and forces in pipe supports are also presented in the paper.
Prediction of Hydrodynamic Forces and Moments on Submarines Using Neural Networks
Authors: Mohamed Ibrahim , Haddara Mahmoud , Williams Christopher D. , Mackay Michael
Published: March 2009

This paper describes a parametric identification tool for predicting the hydrodynamic forces acting on a submarine model using its motion history. The tool uses a neural network to identify the hydrodynamic forces and moments; the network was trained with data obtained from multi-degree-of-freedom captive maneuvering tests. The characteristics of the trained network are demonstrated through reconstruction of the force and moment time histories. This technique has the potential to reduce experimental time and cost by enabling a full hydrodynamic model of the vehicle to be obtained from a relatively limited number of test maneuvers.
Reassessment Issues in Life Cycle Structural Integrity Management of Fixed Steel Installations
Authors: Stacey A. , Birkinshaw M. , Sharp J. V.
Published: March 2009

There is an increasing number of ageing installations in UK waters, many of which are being or will be operated beyond their original planned service life. This important trend, in combination with (a) the introduction of risk-based goal-setting regulations which require the maintenance of life cycle integrity as a key target, (b) the development of guidelines in the draft ISO standard for offshore structures, ISO 19902, and (c) significant technology advances in recent years (e.g. in loading, fatigue, fire and blast integrity and system integrity), makes reassessment an important consideration in the structural integrity management of offshore installations. The paper outlines procedures in place for reassessment, including those in the draft ISO standard, and reviews recent technical advances relevant to this area. The important role of inspection and maintenance for existing structures is assessed and related to both current practices and target requirements. The need for reliable and comprehensive inspection data is important for reassessment and the status of this is reviewed. An overall framework for reassessment is developed in the light of the above issues.
Advances in Designing for Riser Impacts Resulting From VIV
Authors: Morrison Denby , Kim WanJun , Li Yousun , McMullen Doug , Henning Dean , Haws Joe
Published: March 2009

Well bay configurations often attempt to place risers as close as possible without incurring interference. Often avoiding interference is not possible, or resulting spacings are impractical and uneconomical. Alternatively, attempts have been made to quantify the results of impacts incurred by risers in service. Collision tests and numerical analyses have been conducted on pipe-on-pipe collisions to help establish such design guidelines. Collected test data have been scanned to establish the design algorithms for strength assessments and fatigue damage predictions of riser systems. This paper illustrates the methodologies and procedures to obtain the desired information from the test results.
Expanding Wake Induction Effects on Thrust Distribution on a Rotor Disk
Authors: Chaney K. , Eggers A. J.
Published: March 2009

Wake expansion is necessary to satisfy conservation of mass when induction in flow through a wind turbine rotor disk is substantial. An iterative model is developed to calculate this expansion in an axisymmetric wake generated by an idealized unyawed disk operating at high tip speed ratios. The model satisfies all conservation constraints and boundary conditions, and predicts induction in the wake flow normal to the rotor disk plane due to the sheet of vorticity convected downwind along the surface of the wake. Expansion effects on induction in flow through the rotor disk and in the wake ale noted. The effect of skewing the axis of the wake out of alignment with the axis of a yawed rotor disk is approximated with a simple cross flow model which yields an expanding skewed wake. The sheet of vorticity convected downwind along the surface of this wake is found to significantly alter the induction in flow through the rotor disk from that predicted when wake expansion is neglected with the cylindrical wake approximation. This alteration is in the direction of levelizing the induction and resulting thrust distributions on the yawed disk. This in turn reduces the forward shift of the center of thrust from the axis of a yawed rotor, and this reduction may be very substantial at higher levels of induction and hence wake expansion. The effects of wake expansion on the level of thrust appear to be of second order compared to the effects on center of thrust. These findings are likely to be of particular importance to small wind turbines which are designed to yaw out of the wind as required at higher wind speeds to prevent undesirable overshoots in power and loads.
Periodic Disturbance Accommodating Control for Speed Regulation of Wind Turbines
Authors: Stol Karl , Balas Mark
Published: March 2009

Performance of a model-based periodic gain controller is presented using Disturbance Accommodating Control (DAC) techniques to estimate fluctuating wind disturbances. Operation is restricted to speed regulation using Independent Blade pitch Control (IBC) and by measuring only rotor angle and speed. The modeled turbine is a free-yaw, two-bladed, teetered rotor machine with simple blade and tower flexibility — 6 discrete degrees of freedom. A comparison is made to a time-invariant DAC controller, constructed by various approaches. Results indicate that the two controllers perform nearly identically, despite the inherent periodic dynamics in the system. The best time-invariant state estimator model was designed by freezing the periodic plant at a specified rotor azimuth position.
Acoustic Emission Monitoring of Small Wind Turbine Blades
Authors: Joosse P. A. , Blanch M. J. , Dutton A. G. , Kouroussis D. A. , Philippidis T. P. , Vionis P. S.
Published: March 2009

Wind turbine blade certification tests, comprising a static test, a fatigue test, and finally a residual strength test, often involve sudden audible cracking sounds from somewhere within the blade, without the operators being able to locate the noise source, or to determine whether damage (minor or major) has occurred. A current EC-funded research project is looking at the possibility of using acoustic emission (AE) monitoring during testing of fibre composite blades to detect such events and assess the blade condition. AE can both locate and characterise damage processes in blades, starting with non-audible signals occurring due to damage propagation at relatively low loads. The test methodology is discussed in the context of the blade certification procedure and results are presented from a series of static and fatigue blade tests to failure in the laboratory. Inferences are drawn about small differences in the manufacture of the nominally identical blades and conclusions are presented for the application of the methodology.
Asymmetries in the individual distinctiveness and maternal recognition of infant contact calls and distress screams in baboons
Authors: Rendall Drew , Notman Hugh , Owren Michael J.
Published: March 2009

A key component of nonhuman primate vocal communication is the production and recognition of clear cues to social identity that function in the management of these species’ individualistic social relationships. However, it remains unclear how ubiquitous such identity cues are across call types and age-sex classes and what the underlying vocal production mechanisms responsible might be. This study focused on two structurally distinct call types produced by infant baboons in contexts that place a similar functional premium on communicating clear cues to caller identity: (1) contact calls produced when physically separated from, and attempting to relocate, mothers and (2) distress screams produced when aggressively attacked by other group members. Acoustic analyses and field experiments were conducted to examine individual differentiation in single vocalizations of each type and to test mothers’ ability to recognize infant calls. Both call types showed statistically significant individual differentiation, but the magnitude of the differentiation was substantially higher in contact calls. Mothers readily discriminated own-offspring contact calls from those of familiar but unrelated infants, but did not do so when it came to distress screams. Several possible explanations for these asymmetries in call differentiation and recognition are considered.
Steep and shallow phase gradient distortion product otoacoustic emissions arising basal to the primary tones
Authors: Martin Glen K. , Stagner Barden B. , Fahey Paul F. , Lonsbury-Martin Brenda L.
Published: March 2009

Distortion product otoacoustic emission (DPOAE) level/phase maps were collected in humans with and without an interference tone (IT) near the DPOAE frequency place (fdp) at primary-tone levels of 75dB SPL. A DPOAE component with the expected steep phase gradient could be extracted at fdp, however, considerable vertical-phase banding, presumably indicative of reflection emissions, remained. An IT placed 0.33 oct above f2 removed most of this banding, revealing DPOAE components originating basal to the IT frequency place. These findings suggest that the commonly accepted two-source model of DPOAE generation may need to be qualified when higher primary-tone levels are utilized.
Vowel devoicing and the perception of spoken Japanese words
Authors: Cutler Anne , Otake Takashi , McQueen James M.
Published: March 2009

Three experiments, in which Japanese listeners detected Japanese words embedded in nonsense sequences, examined the perceptual consequences of vowel devoicing in that language. Since vowelless sequences disrupt speech segmentation [Norris et al. (1997). Cognit. Psychol. 34, 191–243], devoicing is potentially problematic for perception. Words in initial position in nonsense sequences were detected more easily when followed by a sequence containing a vowel than by a vowelless segment (with or without further context), and vowelless segments that were potential devoicing environments were no easier than those not allowing devoicing. Thus asa, “morning,” was easier in asau or asazu than in all of asap, asapdo, asaf, or asafte, despite the fact that the /f/ in the latter two is a possible realization of fu, with devoiced [u]. Japanese listeners thus do not treat devoicing contexts as if they always contain vowels. Words in final position in nonsense sequences, however, produced a different pattern: here, preceding vowelless contexts allowing devoicing impeded word detection less strongly (so, sake was detected less accurately, but not less rapidly, in nyaksake—possibly arising from nyakusake—than in nyagusake). This is consistent with listeners treating consonant sequences as potential realizations of parts of existing lexical candidates wherever possible.
Anatomic development of the oral and pharyngeal portions of the vocal tract: An imaging study
Authors: Vorperian Houri K. , Wang Shubing , Chung Moo K. , Schimek E. Michael , Durtschi Reid B. , Kent Ray D. , Ziegert Andrew J. , Gentry Lindell R.
Published: March 2009

The growth of the vocal tract (VT) is known to be non-uniform insofar as there are regional differences in anatomic maturation. This study presents quantitative anatomic data on the growth of the oral and pharyngeal portions of the VT from 605 imaging studies for individuals between birth and 19 years. The oral (horizontal) portion of the VT was segmented into lip-thickness, anterior-cavity-length, oropharyngeal-width, and VT-oral, and the pharyngeal (vertical) portion of the VT into posterior-cavity-length, and nasopharyngeal-length. The data were analyzed to determine growth trend, growth rate, and growth type (neural or somatic). Findings indicate differences in the growth trend of segments/variables analyzed, with significant sex differences for all variables except anterior-cavity-length. While the growth trend of some variables displays prepubertal sex differences at specific age ranges, the importance of such localized differences appears to be masked by overall growth rate differences between males and females. Finally, assessment of growth curve type indicates that most VT structures follow a combined/hybrid (somatic and neural) growth curve with structures in the vertical plane having a predominantly somatic growth pattern. These data on the non-uniform growth of the vocal tract reveal anatomic differences that contribute to documented acoustic differences in prepubertal speech production.
An investigation of Rubens flame tube resonances
Authors: Gardner Michael D. , Gee Kent L. , Dix Gordon
Published: March 2009

The Rubens flame tube is a century-old teaching demonstration that allows observers to visualize acoustic standing wave behavior [H. Rubens and O. Krigar-Menzel, (1905). Ann. Phys. 17, 149–164]. Flammable gas inside the tube flows through holes drilled along the top, and flames are then lit above. The tube is closed at one end and driven with a loudspeaker at the other end. When the tube is driven at one of its resonance frequencies, flames form a visual standing wave pattern as they vary in height according to the pressure amplitude in the tube. Although the basic performance of the tube has been explained [G. Ficken and C. Stephenson, (1979). Phys. Teach. 17, 306–310], this paper discusses a previously unreported characteristic of the tube: a shift of the tube’s resonance frequencies away from those predicted by simple introductory physics. Results from an equivalent circuit model of the tube and agreement between experiments and the model suggest that the shift is caused by the presence of the holes. For teachers and educators seeking to better understand and explain the tube to students, this article serves as a resource regarding the basic phenomena affecting the behavior of the tube.
Using time-reversal to generate generalized transversely localized transient waves (X-waves)
Authors: Walker S. C.
Published: March 2009

In the traditional approach to X-waves, the X-wave field is synthesized from a superposition of solutions to the homogenous wave equation (in three-dimensions) without regard to boundary conditions. As a consequence the synthesized solution is acausal. Here, it is shown that the solution to the inhomogenous scalar wave equation for the acoustic field from a supersonic source distribution consistent with the radiation condition, i.e., a Mach front, defines a causal X-wave. Using the connection between X-waves and a physical source, it is shown that an X-wave can be generated from a planar aperture using time-reversal. By appealing to the demonstrated self-adaptivity of time-reversal processes, the method should allow for the generation of X-waves in arbitrary (inhomogenous) media. Typically, the generation of approximate acoustic X-waves from a planar aperture is achieved using a complicated annular transducer arrangement. Here, the time-reversal method for the generation of approximate acoustic X-waves is experimentally proven using a line transducer array in two-dimensional geometry in free space.
Molecular Documentation of
Bartonella
Infection in Dogs in Greece and Italy
Authors: Diniz P. P. V. P. , Billeter S. A. , Otranto D. , De Caprariis D. , Petanides T. , Mylonakis M. E. , Koutinas A. F. , Breitschwerdt E. B.
Published: March 2009

This study reports the occurrence of “
Bartonella rochalimae
” in Europe and the presence of
Bartonella vinsonii
subsp.
berkhoffii
genotypes II and III in dogs in southern Italy and provides DNA sequencing evidence of a potentially new
Bartonella
sp. infecting dogs in Greece and Italy.
Validation of Use of Rectoanal Mucosa-Associated Lymphoid Tissue for Immunohistochemical Diagnosis of Chronic Wasting Disease in White-Tailed Deer (
Odocoileus virginianus
)
Authors: Keane Delwyn , Barr Daniel , Osborn Rebecca , Langenberg Julie , O'Rourke Katherine , Schneider David , Bochsler Philip
Published: March 2009

The examination of rectoanal mucosa-associated lymphoid tissue (RAMALT) biopsy specimens for the diagnosis of transmissible spongiform encephalopathies has been described in sheep, elk, and small numbers of mule and white-tailed deer. Previous sample numbers have been too small to validate examination of this type of tissue as a viable antemortem diagnostic test. In this study, we examined RAMALT collected postmortem from 76 white-tailed deer removed from a farm in Wisconsin known to be affected by chronic wasting disease (CWD) and from 210 free-ranging white-tailed deer harvested from an area in Wisconsin where the overall prevalence of CWD among the deer was approximately 4 to 6%. The results of immunohistochemical (IHC) staining of the RAMALT sections were compared to the results of IHC staining of sections from the brain stem at the convergence of the dorsal motor nucleus of the vagus nerve, sections of the medial retropharyngeal lymph nodes (RLNs), and sections of tonsil (sections of tonsil only from captive animals were tested). The sensitivities of the IHC staining test with RAMALT sections were 81% for the captive animals and 91% for the free-ranging animals. False-negative results were usually associated with early infection, indicated by a low intensity of immunostaining in the obex and/or a polymorphism at
PRNP
codon 96. While the RLN remains the tissue of choice for use for the diagnosis of CWD in white-tailed deer, the results of the present study further support the use of RAMALTs collected antemortem as an adjunct to testing of tonsil biopsy specimens and surveillance by necropsy for the screening of farmed deer which have been put at risk through environmental exposure or exposure to deer with CWD.
Frequency of Protocalliphora avium (Diptera: Calliphoridae) infestations on bald eagles (Haliaeetus leucocephalus)
Authors: Bortolotti Gary R.
Published: March 2009

This is the first record of nestling bald eagles as hosts of the parasitic blowfly Protocalliphora avium (Diptera: Calliphoridae). The frequency of infestation of the hematophagous larvae was determined by repeatedly examining eaglets over the entire 10- to 12-week nestling period from 1980 to 1982 in north-central Saskatchewan. Seventy-two nestlings were examined a total of 461 times. All nestlings less than 49 days old were parasitized by large numbers of larvae in the aural cavities, on the nape of the neck, and on the top of the head. The frequency of parasitism was high from the time the eaglets hatched until they were 16 days old when it sharply declined. The birds were repeatedly infested, suggesting that P. avium may have been an intermittent feeder. There was no difference between the frequency of infestation in nests containing one or two chicks, nor between the first-hatched and second-hatched eaglet within a brood. Factors associated with the physical and behavioural development of the eaglets, rather than a seasonal effect on the parasites, may account for the decline and cessation of infestation.
Low pH avoidance by crayfish (Orconectes virilis): evidence for sensory conditioning
Authors: France R. L.
Published: March 2009

Avoidance responses of crayfish (Orconectes virilis) to low pH were tested for individuals from two populations, one inhabiting a reference lake and one from a lake experimentally acidified over a 5-year period to a mean summer epilimnetic pH of 5.3. Adult and yearling crayfish from the reference population displayed a strong avoidance of potentially lethal water of pH 4.5 and below. However, there was no avoidance demonstrated to water above pH 5.0, which is known to seriously impair reproduction of this species. Animals from the acidified lake had noticeably reduced avoidance, significant at only pH 4.0, with no behavioral modification occurring above pH 4.5.
Patterns of microhabitat use and seed collection within populations of heteromyid rodents
Authors: M'Closkey Robert T.
Published: March 2009

Microhabitat use and seeds in cheek pouches were examined in four species of heteromyid rodent. Individuals of each species were classified as male or female, resident or transient, and adult or juvenile. The following question is addressed: are there any differences in microhabitat use and seed collection within rodent species and are these differences associated with the sex, residence, or age of individuals? For microhabitats, there were significant differences among individuals for each species analyzed. However, these differences could not be attributed to sex, residence, or age groups within populations. In addition, there were no differences within rodent species in the variety or number of seeds contained in individual cheek pouches. In spite of apparent differences in microhabitat use among heteromyid species, individual rodents are extremely variable in their use of microhabitats.
Experiments on the functions of the bare crown patch of downy western grebe chicks
Authors: Nuechterlein Gary L.
Published: March 2009

On the head of western grebe chicks (Aechmophorus occidentalis) is a bare, triangular patch of skin. Field observations and experiments show that this crown patch flushes to a deep scarlet when a chick is begging for food or is separated temporarily from its parents. Both satiation of begging chicks and reuniting of lost, peeping chicks restored the patch to its original pale colour within minutes. The crown patch appears to function as a generalized distress signal that indicates to the parents that a particular member of the brood is in need of immediate attention.
The effect of swarm size and date of issue on comb construction in newly founded colonies of honeybees (Apis mellifera L.)
Authors: Lee P. C. , Winston M. L.
Published: March 2009

The effect of swarm size and date of issue on comb construction was examined in honeybee (Apis mellifera L.) colonies founded by swarms. Significant positive correlations were found between the swarm size and the total amount of comb and percentage of drone comb constructed. Significant negative correlations were found between the date of swarm issue and the total amount of comb and percentage of drone comb produced. The rate of total comb production was rapid, with 90% of all comb being built within 44 days of colony founding. Drone comb construction began an average of 22 days after colony founding, with 90% of the drone comb being built within 42 days after the first drone cells. When temperate and tropically evolved bee races were compared, temperate colonies produced a lower proportion of drone comb than tropical colonies at small colony sizes, but more drone comb in larger colonies.
Genetic variability in freshwater and anadromous sticklebacks (Gasterosteus aculeatus) of southern British Columbia
Authors: Withler R. E. , McPhail J. D.
Published: March 2009

Electrophoretic variation at eight loci was compared between anadromous and freshwater populations of threespine sticklebacks (Gasterosteus aculeatus) collected from 56 sites in southwestern British Columbia and northwestern Washington. Allelic frequencies at five polymorphic loci were heterogeneous among populations and the average allelic frequencies at four loci differed between anadromous and freshwater sticklebacks. The average number of polymorphic loci was greater in anadromous (4.6) than in freshwater (3.2) populations. The average heterozygosity was 0.113 ± 0.001 in anadromous and 0.117 ± 0.003 in freshwater stickleback populations. Anadromous populations were more polymorphic but less heterogeneous than freshwater populations. The standardized genetic variance indicated only moderate differentiation among anadromous populations from marine habitats, but considerable differentiation among populations from freshwater habitats. Our data are consistent with the hypothesis of postglacial polyphyletic origins for freshwater populations of Gasterosteus, but also indicate that selection favours different alleles in marine and freshwater environments, at least at the Mdh-1 locus.
Structural organization of neurosecretory cells terminating in the sinus gland of the terrestrial isopod, Oniscus asellus, revealed by paraldehyde fuchsin and cobalt backfilling
Authors: Chiang R. G. , Steel C. G. H.
Published: March 2009

The morphology of the brain – sinus gland neurosecretory system in the terrestrial isopod, Oniscus asellus, is described with paraldehyde fuchsin and with cobalt backfilling of the sinus gland. Paraldehyde fuchsin stained the A, B, and β cells located medially in the protocerebrum and the γ cells located in the optic lobe. Cobalt applied to the sinus gland delineates an axon tract that extends from the sinus gland medially along the posterior surface of the protocerebrum and descends into the protocerebrum at the level of the central protocerebral neuropile. Cobalt backfilled to the B, β, and γ cells but not to the A cells. One cell group located distally to the most distal optic lobe neuropile filled with cobalt, but was not stained with paraldehyde fuchsin. It is argued that the B and β cells together comprise the equivalent of the decapod "X-organ." Varicosities, which may represent additional storage and (or) release sites for neurosecretion, appear in the axon tract over the region of the optic lobe. Extensive dendritic arborizations of the B and β cells occur along the anterior-medial side of the central protocerebral neuropile. Additional arborizations of these cells occur in the contralateral protocerebral lobe, suggesting a pathway for neural coordination of left and right sinus glands. Further observations on changes in the staining properties of the β and γ cells during the moult cycle suggest the involvement of β cells with moulting and the involvement of γ cells with egg development.
The morphology of Placobdella multilineata (Hirudinoidea: Glossiphoniidae), a parasite of Crocodilia
Authors: Yang Tong , Davies Ronald W.
Published: March 2009

Based on 34 specimens, the external and internal morphology of Placobdella multilineata, a parasite of Crocodilia, are described and compared with the less complete published descriptions.
Fine structure of the external egg membrane of five species of Pacific salmon and steelhead trout
Authors: Groot E. P. , Alderdice D. F.
Published: March 2009

Fine structure of the external egg membrane of five species of Pacific salmon (sockeye, Oncorhynchus nerka; pink, O. gorbuscha; chum, O. keta; coho, O. kisutch; and chinook, O. tshawytscha) and the anadromous steelhead trout (Salmo gairdneri), is examined and compared using the scanning electron microscope. Membrane thickness in fixed material varies for the six species as follows (micrometres, [Formula: see text]): sockeye, 34.15 ± 0.15; pink, 61.64 ± 1.53; chum, 53.05 ± 0.33; coho, 27.96 ± 0.48; chinook, 50.82 ± 0.74; steelhead, 30.74 ± 0.11. The membrane consists of a thin outermost layer, the externus, 0.2–0.3 μm thick, and the internus, 24–55 μm thick, which constitutes the remainder of the membrane. In sockeye, pink, and chum salmon and steelhead trout, an additional layer 3–8 μm thick, the "subinternus," occurs beneath the internus. The entire membrane appears fibrous except for the thin and apparently solid externus. Pores in both the inner and outer surfaces are arranged in a hexagonal pattern and are connected by pore canals traversing the membrane. Except in the sockeye, plugs commonly were seen blocking the external openings of the pore canals. Significance of the egg membrane fine structure is considered in relation to several of its roles in the water-activated egg: semipermeability, retention of internal pressure, and mechanical protection. A structural and functional analogy is drawn between the fine structure of the salmonid egg membrane and the mammalian aorta.
Stable carbon isotope ratios in Periplaneta americana L., the American cockroach
Authors: Miller R. F. , Orr G. L. , Fritz P. , Downer R. G. H. , Morgan A. V.
Published: March 2009

The distribution of stable carbon isotopes in carbohydrate, lipid, and protein of Periplaneta americana was studied in insects raised on two different diets. Cockroaches that received a sucrose supplement in their diet had chitin and lipids enriched in 13C compared with those insects not given sucrose. Sucrose has a high 13C content relative to the other dietary constituents and enrichment was due to the incorporation of sucrose carbon into these body fractions. The isotope ratios of protein and glycogen from insects raised on a low carbohydrate diet differed significantly from those fed sucrose. Respiratory CO2 collected from insects receiving sucrose was more enriched in 13C than that from insects on the other diet, reflecting the source of metabolic fuel. Starved insects showed a general decline in the heavier isotope in respired carbon dioxide, as lipids were used as an energy source. Cockroaches that were injected with corpus cardiacum extract responded by respiring CO2 depleted in 13C, a result similar to those induced by starvation. This result is consistent with experiments demonstrating a switch from carbohydrate to lipid oxidation caused by corpus cardiacum extract.
Variations cycliques de la tolérance à un choc thermique froid appliqué au cours de la segmentation de l'embryon de la carpe commune (Cyprinus carpio L.)
Authors: Roubaud P. , Chaillou C. , Sjafei D.
Published: March 2009

Common carp (Cyprinus carpio L.) eggs incubated at 16 °C were plunged into melting ice (0.3 °C) during the first cleavage stages with the aim of determining their sensitivity to cold shock. The effects of the shocks were estimated by the survival rates of embryos on days 2 and 6 of prehatching. After a brief cold shock (10 min), embryos showed a regular succession of sensitive and tolerant phases. Survival rates indicated that there were 9 sensitive phases at the caudal bug stage and 12 at the prehatching stage. This rhythm corresponded to the periodicity of cell division in the rapid cleavage stage. The embryos became progressively more tolerant to cold shock. With an increase in the duration of the cold shock (50 min), an assymetrical widening of the mortality peaks was observed. The progressive acquisition of tolerance to cold shock in carp embryos might be related to a desynchronisation and a slowing down of the cell cycles during the early cleavage stages.
Eulimdana lari (Yamaguti, 1935) n. comb. (Nematoda: Filarioidea) from Phalaropus spp. (Charadriiformes) in Canada and a review of the genus Eulimdana Founikoff, 1934
Authors: Bartlett Cheryl M. , Wong Pooi Leng , Anderson Roy C.
Published: March 2009

Eulimdana lari (Yamaguti, 1935) n. comb. (Nematoda: Filarioidea) was found in 1 of 26 Phalaropus lobatus (L.) and 3 of 9 P. tricolor (Vieillot) collected in Canada near Deer Island, New Brunswick, and Delta, Manitoba, respectively. This is the first report of the parasite in the New World and extends the distribution of the parasite across the Holarctic. Eulimdana lari is now known from 17 species of Charadriiformes, including P. tricolor which is a new host record. It is suggested that E. lari is a parasite of shorebird communities. Eulimdana lari is redescribed and a taxonomic review of Eulimdana Founikoff, 1934 is provided, including an amended generic diagnosis and an annotated list of the five species. Heimnema Chabaud, Brygoo, and Richard, 1964 is placed in synonymy with Eulimdana. In addition to E. lari (Yamaguti, 1935) n. comb., the following changes are made: E. micropenis (Travassos, 1926) n. comb. and E. heimi (Chabaud, Brygoo, and Richard, 1964) n. comb. Eulimdana mazzantii (Railliet, 1893) Neveu-Lemaire, 1936, is considered a species inquirenda. It is pointed out that the type species, E. clava (Wedl, 1856) Founikoff, 1934 has a worldwide distribution in pigeons.
Effects of a subminiature radio collar on activity of free-living white-footed mice
Authors: Ormiston Brian G.
Published: March 2009

The effects of a subminiature (1.1 g) radio collar on activity of free-living Peromyscus leucopus were examined by comparing recapture frequency, persistence, apparent reproduction, body weight, and ranging activity of 43 collared and 304 uncollared mice. Although some differences between collar treatment groups were noted for most measures, no significant deleterious effects of wearing the radio collar were detected. Collared juveniles weighing from 12 to 16 g appeared to grow and mature similarly relative to uncollared juveniles.
Parasitic copepods of the white shark (Carcharodon carcharius L.) from the Bay of Fundy
Authors: Hogans William E. , Dadswell Michael J.
Published: March 2009

Two white sharks (Carcharodon carcharius L.) collected in the Bay of Fundy were examined for parasitic copepods. Three species were recovered: Anthosoma crassum, Dinemoura latifolia, and Pandarus sinuatus. None of these have previously been reported from the white shark in Canadian waters.
Avoidable obstacles to colonization in classical biological control of insects
Authors: Beirne Bryan P.
Published: March 2009

Most classical biological control attempts worldwide against pest insects have failed to meet the objective of solving the pest problems permanently. The dominant cause was failure by introduced agents to colonize. Most failures to colonize can be attributed to procedures that were detrimental to the numbers or health or the target-finding or field survival abilities of newly released agents. Administrative reactions to the low success rate, poor cost/benefit data, and overselling of the method were basically responsible for those procedures. As ways of avoiding such procedures exist, it is feasible to make colonization a probability. This should substantially improve the chances of control being successful, enable past failures to be reopened, and expand the scope of classical biological control.