bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Approach to the Design of Self-Piloting Drills With External Chip Removal, Part 2: Bottom Clearance Topology and Experimental Results
Authors: Astakhov V. P. , Galitsky V. V. , Osman M. O. M.
Published: February 2008

In the first part of this paper, geometrical relations were formulated to describe the geometry of a self-piloting drill with external chip removal. A novel approach to the design of the cutting tip was proposed and an experimental comparison between conventional and newly designed drills was made. In deep hole drilling, after the tool and the machine, the most important component is the coolant. It is important that the coolant be distributed uniformly within the machining zone to improve chip removal, lubrication and cooling. Thus, in this paper, the coolant flow in the limited space between the drill flanks and the bottom of the hole being drilled (called “bottom clearance”) is emphasized. Experimental investigations were done by using a specially designed workpiece which enables continuous monitoring of coolant flow and pressure distribution in the machining zone. The investigation shows that the newly designed drill is characterized by a significantly better coolant distribution in the bottom clearance resulting in an increase in tool life and better chip removal conditions.
Effect of Abrasive Waterjet Parameters on Volume Removal Trends in Turning
Authors: Ansari A. I. , Hashish M.
Published: February 2008

An experimental investigation was conducted to investigate the influence of abrasive waterjet parameters on the volume removal rate in abrasive waterjet turning. Abrasive mass flow rate, abrasive particle size, waterjet pressure, and orifice diameter were the principal variables that were investigated. Limited tests were also conducted with abrasive mixtures. The results show that the volume removal trends in abrasive waterjet turning are similar to those in linear cutting with abrasive waterjets. Increasing waterjet pressure, orifice diameter, and abrasive flow rate generally resulted in an increase in volume removal rate. However, the volume removal rate levels off either due to volume sweep rate limit or due to the abrasive waterjet limit. The results also suggest a potential for optimizing the abrasive flow rate and abrasive composition. The volume removal rate showed only a weak dependence on the abrasive particle size.
Regenerative Chatter Vibration Occurring in Turning With Different Side Cutting Edge Angles
Authors: Marui E. , Hashimoto M. , Kato S.
Published: February 2008

This paper deals with the regenerative chatter vibration occurring in cutting tools with different side cutting edge angles. The occurrence of regenerative chatter vibration of the cutting tool is influenced by two factors, which are closely related to the vibratory energy supply or consumption. One factor is the interference effect between the tool flank and the workpiece. Of course, this factor exists in the primary chatter, too. The other is the regenerative effect. The influence of both factors on the regenerative chatter vibration of cutting tools with different side cutting edge angles is examined experimentally. The vibratory energy supply is simulated, considering the dynamic cutting process. As a result, the property of the regenerative chatter vibration and the influence of the side cutting edge angle on the regenerative chatter vibration are clarified.
An Optimization Strategy for Maximizing Coordinate Measuring Machine Productivity, Part 2: Problem Formulation, Solution, and Experimental Results
Authors: Jones S. D. , Ulsoy A. Galip
Published: February 2008

In this, the second of two papers focused on optimizing CMM productivity, a strategy is presented for obtaining operating speeds that maximize CMM throughput. The strategy involves posing the objective and constraints in terms of a nonlinear programming problem. The objective is to minimize measuring time, and constraints are on measurement quality, available motor power and other machine specific characteristics. Solutions to various measurement scenarios are given, computed with a generalized conjugate gradient method that uses a golden section acceptable search method. Also, a sensitivity study is presented that utilizes the optimization strategy to determine how change to a CMM’s design will affect overall productivity. In the final section, experimental results utilizing the optimally computed trajectories for both single axis and multiple axis motion are given. In addition, an example is presented to demonstrate the implementation of the optimization strategy in an actual measuring application. In the example, a connecting-rod is measured at three speeds: the machine’s default speed, a speed constrained by available motor power, and the optimized speed (constrained additionally by measurement quality). The experiment demonstrates a 27 percent reduction in time for the optimized speed compared to the default speed using the Bartlett test for comparing variances in the dimensional data obtained.
Chip Load Kinematics in Milling With Radial Cutter Runout
Authors: Wang J.-J. Junz , Liang S. Y.
Published: February 2008

This paper presents the analytical modeling of chip load and chip volume distribution in milling processes in the presence of cutter runout. The understanding of chip load kinematics has a strong bearing on the prediction of milling forces, on the assessment of resulting surface finish and tool vibration, and on the identification of runout for multi-toothed machining process monitoring and control. In this study a chip thickness expression is analytically established in terms of the number of flutes, the cutter offset location and the ratio of offset magnitude to feed per tooth. The effects of runout geometry, feed rate, and depths of cut on the overall chip generating action is discussed through the illustration of cutting regions and chip load maps. Explicit solutions for the entry and exit angles are formulated in the context of milling parameters and configuration. Experimental measurement of the resulting chip volumes from machining with an offset cutter is compared to an analytical model formulated from the chip thickness expression. Additionally, an average chip thickness prediction, based on the chip volume model in combination with the entry/exit angle solutions, is compared to data reported in the literature for validity assessment.
Dynamic Analysis and Identification of Gas Tungsten Arc Welding Process for Weld Penetration Control
Authors: Zhang Y. M. , Kovacevic R. , Wu L.
Published: February 2008

In this study, gas tungsten arc welding is analyzed and modeled as a 2-input (welding current and arc length) 2-output (weld depression and width) multivariable process. Experiments under a number of typical welding conditions are performed to excite and identify the process characteristics and variations. It is observed that the model parameters vary in a large range with the experimental conditions. A real-time model frame with only a few parameters to be identified on-line is proposed. Based on the obtained models, the process characteristics in terms of inertia, delay, nonminimum phase, and coupling are given. These characteristics suggest an adaptive predictive decoupling control algorithm. By designing and implementing the suggested control algorithm with the real-time model, excellent results have been achieved for both simulation and practical control. This shows that the dynamic analysis and identification provide sufficient process information for design of the control system.
Inverse Heat Transfer Analysis of Grinding, Part 2: Applications
Authors: Guo C. , Malkin S.
Published: February 2008

Distributions of the heat flux to the workpiece and the convection heat transfer coefficient on the workpiece surface during straight surface grinding are estimated from measured temperatures in the workpiece subsurface using inverse heat transfer methods developed in Part 1. The results indicate that the heat flux to the workpiece is distributed approximately linearly (triangular heat source) along the grinding zone with about 70 to 75 percent of the total energy transported as heat to the workpiece for grinding of steels with a conventional aluminum oxide wheel and only about 20 percent with CBN superabrasive wheels. The wheel-workpiece contact length corresponding to the region of positive heat flux to the workpiece is found to be generally close to but slightly longer than the theoretical geometric contact length. The convection heat transfer coefficient for cooling by the applied grinding fluid is greatest just behind the trailing edge of the grinding zone where fluid is directly applied, and negligible ahead of the grinding zone.
Measurement of Temperature and Heat Flux Changes During the Fixing Process in Electrophotographic Machines
Authors: Mitsuya T. , Masuda K. , Hori Y.
Published: February 2008

Increasingly higher speeds of modern electrophotographic printing force examination of the problem of retaining sufficient fixing strength without deterioration of print quality. In the nip region between the two rollers where fixing occurs, the significant parameters are temperature, heat flux, and pressure changes. Their optimization is necessary to maintain both speed and print quality. Difficulty in analyzing the relationship among these parameters occurs because of the complexity of two-dimensional phenomena in a rotating field and the rapidity of changes. Experimental equipment to measure relative heat flux in the nip region during rapid temperature changes was designed. Two sensors are installed in the heat roller. An adiabatic piece is buried under sensor 1. Sensor 2, without an adiabatic piece, detects temperature. Sensor 1 is electrically heated and always at the same temperature as sensor 2. Heat flux changes are obtained by noting the electric power supplied to sensor 1. The equipment was fabricated and measurements were made. They indicate an intermittent two-dimensional heat flux. Because of this, temperature decreases rapidly before the entrance to the nip region. Estimates of two-dimensional effects are made and modified for a one-dimensional case. From them, the temperature field in the nip region for actual fixing conditions is calculated.
Feed, Speed, and Torque Controllers for Drilling
Authors: Furness R. J. , Ulsoy A. Galip , Wu C. L.
Published: February 2008

The design and implementation of feed, speed, and torque controllers for drilling is discussed. Dynamic models of the feedrate drive and spindle motors were developed using experimental data and least squares estimation. These dynamic models were subsequently used to design closed loop feed and speed controllers, which allow for independent control of the machining feed and speed during drilling. They effectively track constant, as well as step-change, command references. Subsequently, the feed controller was used to develop a dynamic model between feed and torque, and then was cascaded with a torque control loop. The dynamic modeling and subsequent closed loop controller design and performance are described.
An Integrated Lattice Filter Adaptive Control System for Time-Varying CMM Structural Vibration Control, Part 1: Theory and Simulation
Authors: Lu E. , Ni J. , Wu S. M.
Published: February 2008

An integrated lattice filter adaptive control system is developed for the control of time-varying CMM structural vibrations. An efficient algorithm is developed to provide a link between the adaptive lattice filter and the minimum variance control by directly utilizing the lattice filter parameters at time t − 1 for control. The approach avoids the conversion to system parameters and is therefore computationally efficient for applications of real time control. To fully utilize the benefit of the lattice filter, a heuristic criterion for on-line order determination is developed using the lattice filter parameters. With a linear computational cost, the developed algorithm will perform on-line system order determination, parameter tracking, and control calculation at each sampling instance. The simulation result shows that the approximation of output prediction is reasonable and the integrated lattice filter adaptive control can reduce the system settling time by 82 percent as compared with no control.
Cutting Force Dynamics as a Tool for Surface Profile Monitoring in AWJ
Authors: Kovacevic R. , Mohan R. , Zhang Y. M.
Published: February 2008

Abrasive waterjet cut surface is characterized using static and dynamic characterization techniques. A novel method of auto regressive moving average model identification called model distance method is utilized here for surface profile and dynamic force characterization. More information about the surface profile generating mechanism is derived through wavelength decomposition of the ARMA models. The dynamic workpiece normal force in abrasive waterjet is influenced by process parameters such as fluctuations in water pressure, change in abrasive flow rate, vibration of the positioning system, traverse speed, nozzle diameter, etc. An attempt has been made in this paper to link the dynamics of the process to the quality of the generated surface. The feasibility of using the dynamic workpiece normal force as a parameter for on-line monitoring of the surface profile generated by abrasive waterjet is also investigated.
An Adaptive Methodology for Machine Tool Error Correction
Authors: Mou J. , Liu C. R.
Published: February 2008

An adaptive methodology for machine tool error correction is presented in this paper. The estimated errors resulting from the proposed methodology could be used to adjust the depth of cut on the finish pass or correct the probing data for on-machine inspection to improve the accuracy of workpiece. A generalized error model is derived, using rigid body kinematics, to describe the error motion between the cutting tool and workpiece. Process-intermittent gauging and state observation techniques are integrated to monitor the thermally induced errors and then to modify the error model’s coefficients as the cutting process proceeds. Analysis-of-variance (ANOVA) is used to identify the significant variables for thermal effect modeling. A multiple linear regression model is derived to identify the dynamics of the time-varying thermally induced errors. Multivariable state observers are constructed to track the thermal effect in real time and to fine tune the error model’s coefficients. Experimental results show that the time-varying machine tool errors can be estimated with desirable accuracy.
Case Studies on Modeling Manufacturing Processes Using Artificial Neural Networks
Authors: Fan Hua-Tzu , Wu S. M.
Published: February 2008

The modeling capability of an artificial neural network is studied through three different manufacturing processes. The first case study is a linear separable pattern classification problem in manufacturing process diagnosis. The performance between the neural network and the probability voting classifier is compared. The second case study uses a design of experiment to study an SMC compression molding process. Modeling and predicting performances between a regression model and a neural network model are compared in linear as well as nonlinear cases. The third case study investigates correlation models between the operating conditions and product quality defects of an automotive painting process. Results from a neural network model are compared with those of a probability voting classifier. An ad hoc modification named focused learning paradigm on the back-propagation algorithm is also introduced to speed up network learning.
An Error Compensation Strategy for Replication by Rapid Prototyping
Authors: Philpott M. L. , Green P. A.
Published: February 2008

A generic closed-loop strategy for error compensation is presented which extracts and mathematically models the geometry of sculptured artifacts, and compensates for cumulative error build-up during replication. Experimental results using this strategy demonstrate that a considerable improvement in the accuracy of the end product can be achieved. The replication process involves scanning, CAD solid model creation, rapid prototyping utilizing the stereolithography process, the production of room temperature vulcanized (RTV) molds, the casting of polyurethane parts from the RTV mold, abrasive finishing processes associated with these prototyping processes, and the CNC machining of production molds and dies. At each stage in the replication process, the surface errors (caused primarily by material shrinkage, layer curling, internal stresses, chemical curing phenomena, and material removal during mechanical surface finishing) are tracked and used in subsequent production, through an iterative process of surface fitting and surface compensation.
Surface Roughness Measurement by Ultrasonic Sensing for In-Process Monitoring
Authors: Shin Y. C. , Oh S. J. , Coker S. A.
Published: February 2008

This paper presents a new surface roughness measurement technique suitable for in-process monitoring in production machining processes. The technique is based on the utilization of focused ultrasonic beams with non-zero incidence angle and measurement of reflected intensities. Fundamental principles and the measurement system developed are described along with experimental results. The tests were conducted to test the sensitivity and robustness of the proposed technique with various milled surfaces and materials. The results show excellent correlations with those obtained by a profilometer. In addition, it is shown that the periodicities of the surface profile corresponding to feed marks can be extracted from the measured ultrasonic signals, thus providing the possibility of profiling. Finally, in-process monitoring of surface roughness during machining is demonstrated with the proposed technique.
Emergence of Fluoroquinolone Resistance in Group B Streptococcal Isolates in Taiwan
Authors: Wu Hsiu-Mei , Janapatla Rajendra Prasad , Ho Yueh-Ren , Hung Kuei-Hsiang , Wu Chi-Wen , Yan Jing-Jou , Wu Jiunn-Jong
Published: February 2008

Of 1,994 group B streptococcal isolates collected, 26 (1.3%) of the isolates were resistant to levofloxacin, and cross-resistance to other fluoroquinolones was observed. The emergence and prevalence of high-level fluoroquinolone resistance in genetically unrelated isolates were linked to the presence of
gyrA
,
parC
, and
parE
triple mutations in each isolate.
Isobolographic Analysis of Pharmacodynamic Interactions between Antifungal Agents and Ciprofloxacin against
Candida albicans
and
Aspergillus fumigatus
Authors: Stergiopoulou Theodouli , Meletiadis Joseph , Sein Tin , Papaioannidou Paraskevi , Tsiouris Ioannis , Roilides Emmanuel , Walsh Thomas J.
Published: February 2008

Patients suffering from invasive mycoses often receive concomitant antifungal therapy and antibacterial agents. Assessment of pharmacodynamic interactions between antifungal and antibacterial agents is complicated by the absence of a common antifungal end point for both agents. Ciprofloxacin has no intrinsic antifungal activity but may interact with antifungal agents, since it inhibits DNA gyrase (topoisomerase II), which is abundant in fungi. We therefore employed isobolographic analysis adapted to incorporate a nonactive agent in order to analyze the potential in vitro interaction between the fluoroquinolone ciprofloxacin and several representative antifungal agents against
Candida albicans
and
Aspergillus fumigatus
strains by using a microdilution checkerboard technique. In agreement with earlier in vitro studies, conventional fractional inhibitory concentration index analysis was unable to detect interactions between ciprofloxacin and antifungal agents. However, isobolographic analysis revealed significant pharmacodynamic interactions between antifungal agents and ciprofloxacin against
C. albicans
and
A. fumigatus
strains. Amphotericin B demonstrated concentration-dependent interactions for both species, with synergy (interaction indices, 0.14 to 0.81) observed at ciprofloxacin concentrations of <10.64 μg/ml. Synergy (interaction indices, 0.10 to 0.86) was also found for voriconazole and caspofungin against
A. fumigatus
. Isobolographic analysis may help to elucidate the pharmacodynamic interactions between antifungal and non-antifungal agents and to develop better management strategies against invasive candidiasis and aspergillosis.
Pharmacokinetic Evaluation of Single-Dose Intravenous Daptomycin in Patients with Thermal Burn Injury
Authors: Mohr John F. , Ostrosky-Zeichner Luis , Wainright David J. , Parks Donald H. , Hollenbeck Timothy C. , Ericsson Charles D.
Published: February 2008

Daptomycin pharmacokinetics were evaluated for burn patients. Burn patients had decreases in the maximum concentration of the drug in serum (44%) and the area under the concentration-time curve (47%) and increases in the volume of distribution (64%) and total clearance (77%) compared to healthy volunteers. In burn patients, daptomycin at 10 to 12 mg/kg of body weight/day would be required to achieve drug exposures similar to those for healthy volunteers receiving 6 mg/kg.
Efficacy of SPK-843, a Novel Polyene Antifungal, in Comparison with Amphotericin B, Liposomal Amphotericin B, and Micafungin against Murine Pulmonary Aspergillosis
Authors: Kakeya Hiroshi , Miyazaki Yoshitsugu , Senda Hisato , Kobayashi Tsutomu , Seki Masafumi , Izumikawa Koichi , Yanagihara Kazunori , Yamamoto Yoshihiro , Tashiro Takayoshi , Kohno Shigeru
Published: February 2008

SPK-843, a new polyene antifungal, exhibited dose-dependent efficacy on murine pulmonary aspergillosis models. SPK-843 doses of higher than 1.0 mg/kg of body weight exhibited no renal toxicities and a tendency toward better survival prolongation than the estimated maximum tolerated doses of amphotericin B (Fungizone) (1.0 mg/kg) and liposomal amphotericin B (AmBisome) (8.0 mg/kg).
Translational Attenuation and mRNA Stabilization as Mechanisms of
erm
(B) Induction by Erythromycin
Authors: Min Yu-Hong , Kwon Ae-Ran , Yoon Eun-Jeong , Shim Mi-Ja , Choi Eung-Chil
Published: February 2008

Translational attenuation has been proposed to be the mechanism by which the
erm
(B) gene is induced. Here, we report genetic and biochemical evidence, obtained by using erythromycin as the inducing antibiotic, that supports this hypothesis. We also show that erythromycin increases the level of the
erm
(B) transcript by stalling the ribosome on the leader mRNA and thereby facilitating the stabilization and processing of the mRNA. Erythromycin-induced mRNA stabilization and processing were observed with an ochre stop at codons 11 to 13 of the leader but not with an ochre stop at codon 10. This suggests that erythromycin does not stall the ribosome before codon 11 of the leader reaches the aminoacyl site. Secondary structure analyses of the
erm
(B) transcripts by in vitro and in vivo chemical probing techniques identified conformational changes in the transcripts that result from induction by erythromycin. These findings demonstrate that stalling of erythromycin-bound ribosomes at leader codon 11 causes the refolding of mRNA into a conformation in which the translational initiation site for the structural gene is unmasked and renders
erm
(B) translationally active.
The C-Terminal Segment of the Cysteine-Rich Interdomain of
Plasmodium falciparum
Erythrocyte Membrane Protein 1 Determines CD36 Binding and Elicits Antibodies That Inhibit Adhesion of Parasite-Infected Erythrocytes
Authors: Mo Min , Lee Hooi Chen , Kotaka Masayo , Niang Makhtar , Gao Xiaohong , Iyer Jayasree Kaveri , Lescar Julien , Preiser Peter
Published: February 2008

Attachment of erythrocytes infected by
Plasmodium falciparum
to receptors of the microvasculature is a major contributor to the pathology and morbidity associated with malaria. Adhesion is mediated by the
P. falciparum
erythrocyte membrane protein 1 (PfEMP-1), which is expressed at the surface of infected erythrocytes and is linked to both antigenic variation and cytoadherence. PfEMP-1 contains multiple adhesive modules, including the Duffy binding-like domain and the cysteine-rich interdomain region (CIDR). The interaction between CIDRα and CD36 promotes stable adherence of parasitized erythrocytes to endothelial cells. Here we show that a segment within the C-terminal region of CIDRα determines CD36 binding specificity. Antibodies raised against this segment can specifically block the adhesion to CD36 of erythrocytes infected with various parasite strains. Thus, small regions of PfEMP-1 that determine binding specificity could form suitable components of an antisequestration malaria vaccine effective against different parasite strains.
Predominance of Interferon-Related Responses in the Brain during Murine Malaria, as Identified by Microarray Analysis
Authors: Miu Jenny , Hunt Nicholas H. , Ball Helen J.
Published: February 2008

Cerebral malaria (CM) can be a fatal manifestation ofPlasmodium falciparuminfection. We examined global gene expression patterns during fatal murine CM (FMCM) and noncerebral malaria (NCM) by microarray analysis. There was differential expression of a number of genes, including some not yet characterized in the pathogenesis of FMCM. Some gene induction was observed duringPlasmodium bergheiinfection regardless of the development of CM, and there was a predominance of genes linked to interferon responses, even in NCM. However, upon real-time PCR validation and quantitation, these genes were much more highly expressed in FMCM than in NCM. The observed changes included genes belonging to pathways such as interferon signaling, major histocompatibility complex processing and presentation, apoptosis, and immunomodulatory and antimicrobial processes. We further characterized differentially expressed genes by examining the cellular source of their expression as well as their temporal expression patterns during the course of malaria infection. These data identify a number of novel genes that represent interesting candidates for further investigation in FMCM.
A semi-Markov formulation of the pavement maintenance optimization problem
Authors: Nesbit Dale M. , Sparks Gordon A. , Neudorf Russell D.
Published: February 2008

The problem of determining optimal pavement maintenance and rehabilitation strategies is a special case of a more general problem termed the asset depreciation problem. Perhaps the most general formulation and solution of the asset depreciation problem is the semi-Markov formulation. This paper illustrates how the semi-Markov formulation and solution of the general asset depreciation problem can be applied to pavements. The semi-Markov formulation, like the Markov formulation, characterizes pavement deterioration probabilistically and represents human intervention (maintenance and rehabilitation) as slowing or modifying the basic probabilities of deterioration. The Markov formulation, first implemented for the state of Arizona, is shown to be a special case of the more general, less computationally intensive semi-Markov formulation. The application of the semi-Markov formulation is illustrated at the project level for a heavy-duty pavement in Manitoba. Key words: asset depreciation, infrastructure management, pavement management, probabilistic modelling, Markov, semi-Markov, maintenance optimization, project level.
Amélioration de méthodes d'estimation des débits journaliers
Authors: Bennis Saad , Bruneau Pierre
Published: February 2008

The aim of the research described in this paper was to improve results obtained with conventional daily streamflow estimation methods. The technique requires a robust filter such as the Kalman filter. An explanation of the general filtering algorithm is first given, followed by illustration of how the robust-filter technique can be combined with daily streamflow estimation methods to improve performance. In particular, missing data estimates were more precise with the robust filter, and independent residuals with autocorrelation functions close to zero were obtained. The Saint-François River basin was used as a physical test area. Key words: Kalman filter, missing streamflow record, persistence, extrapolation, noise covariance matrix, residual autocorrelation. [Journal translation]
Influence des caractéristiques des boues digérées en aérobiose sur la solubilisation biologique des métaux
Authors: Couillard D. , Chartier M.
Published: February 2008

A process for metal removal by thiobacilli was applied to aerobic sludge from three different sources: treated sludge not subjected to phosphate removal, sludge subjected to a FeCl3 phosphate-removal process, and sludge subjected to an alum phosphate-removal process. Solubilization varied, and a number of hypotheses were formulated and tested to explain the results: influence of digestion factors, addition of Percol, metal concentrations of the sludge, and phosphate-removal processes during sludge generation. Sludge digestion and addition of Percol proved not to affect metal solubilization resulting from application of the metal removal process. Solubilized copper concentration was plotted against copper content of the sludge studied, yielding a regression with an r2 of 0.72. For manganese, an r2 of 0.53 was obtained for the same type of regression. The more contaminated the sludge, the higher the element solubilization (%). Copper solubilization correlated with sludge phosphate content (r2 = 0.46), suggesting the phosphate-removal process affected copper solubilization. With manganese, no correlation with phosphate content was established. Under optimum reactor operating conditions, metal content was the main factor in copper and manganese solubilization in the aerobic sludges studied. Key words: heavy metals, biological solubilization, thiobacilli, Thiobacillus ferrooxidans, sewage sludge. [Journal translation]
Comparative arboreal behaviors of wild-caught and captive-born deer mice, Peromyscus maniculatus Wagner, from Isle Haute and mainland Nova Scotia
Authors: Pulsifer M. D. , Herman T. B.
Published: February 2008

Locomotor, climbing, and nesting behaviors of wild-caught and captive-born deer mice (Peromyscus maniculatus Wagner) from mainland Nova Scotia and from an isolated predator- and competitor-free island were compared in a laboratory observation room. Locomotor activity did not differ consistently between populations, but wall-seeking was significantly greater in mainland mice. When exposed to an artificial tree, insular mice made more climbs than mainland mice, but mainland mice climbed for longer periods. Climbing behavior differed little between males and females in any group. In a choice experiment, mainland mice selected elevated nest sites significantly more often than ground-level nest sites, while insular mice exhibited no preference.
Habitat use by small mammals on early-growth clear-cuttings in western Oregon
Authors: Morrison Michael L. , Anthony Robert G.
Published: February 2008

Abundance and habitat relationships of small mammals were studied on two early-growth clear-cuttings in the Oregon Coast Range. Ten species were captured in 3 years of study; Peromyscus maniculatus accounted for the majority (64%) of captures. Six other species were captured frequently enough for habitat analyses: Microtus oregoni (15%), Eutamias townsendii (11%), Zapus trinotatus (3%), Sorex vagrans (3%), Sorex trowbridgii (2%), and Sorex pacificus (2%). The small-mammal community was composed of a single, numerically dominant habitat generalist (Peromyscus) and several numerically subordinate species that showed varying degrees of habitat specificity. An overall significant difference in habitat use among the seven species was demonstrated with discriminant function analysis; this separation was based primarily on differences in the use of forb and grass cover. However, there was high overlap in microhabitat associations among species, which was likely due to the environment in regenerating coniferous forests.
Switch in the overwintering strategy of two insect species and latitudinal differences in cold hardiness
Authors: Kukal Olga , Duman John G.
Published: February 2008

A switch from freezing tolerance to freezing intolerance (avoidance) occurred between winter 1980 and winter 1981 in Dendroides canadensis and between 1979 and 1983 in Cucujus clavipes at the same geographical location in northern Indiana (41°30′N). This change in overwintering strategy was not related to latitudinal interpopulation differences, because different populations (latitude range 35°30′N–45°20′N) subsequently sampled were all intolerant of freezing. A 1-week midwinter thaw had no effect on the overwintering mode or cold hardiness of the midlatitude population of D. canadensis. However, high-latitude populations of D. canadensis were more cold hardy (survived 24-h freezing at temperatures above −25 °C) than populations from low latitudes (survived freezing at temperatures above −15 °C). All individuals of the northernmost populations survived low temperatures (−15 °C for 2 weeks) whereas only 14% of the southern-ranging individuals survived that temperature regime.
Tolerance of hatchling painted turtles to subzero temperatures
Authors: Packard Gary C. , Packard Mary J. , McDaniel Paul L. , McDaniel Leonard L.
Published: February 2008

We measured temperatures inside seven natural nests of painted turtles (Chrysemys picta) at our study site in north central Nebraska during the winter of 1987–1988. Although the lowest temperature recorded in some nests was only slightly below 0 °C, the minimum temperature measured in other nests was as low as −6.2 °C. Viable hatchlings were present in all of the nests at the end of the winter, however, which indicates that hatchling painted turtles can withstand exposure to low temperatures that would kill hatchlings of other species.
The effects of source and destination on growth and metal uptake in freshwater clams reciprocally transplanted among south central Ontario lakes
Authors: Hinch Scott G. , Green Roger H.
Published: February 2008

The relative contributions of genotype and environment to growth and metal uptake in freshwater unionid clams (Elliptio complanata) were evaluated using a reciprocal transplant experiment. In August 1985, comparable sites were selected in three south central Ontario lakes with alkalinities of 22, 153, and 238 μequiv.∙L−1. Shell length, height, and width varied in a manner that could not be related to lake alkalinities. There were differences among the clam populations in allelic frequencies (at the Pgm and Lap-2 loci). Clams were marked, measured, and reciprocally transplanted among the three lakes. In August 1986, marked individuals were recovered, remeasured, and analysed for levels of Cu, Zn, Mn, and Cd in soft tissues. The transplant source had a strong influence on clam growth during the post-transplant year. This source effect may result from genetic differences among the populations. Tissue metal concentrations at the end of the post-transplant year were a function of both source and destination. The use of freshwater clams as transplant biomonitors must be reassessed since there is a strong source component to growth and metal uptake. In transplant experiments a common source (a particular site within a particular lake) should be used, and post-transplant periods of more than 1 year may be necessary for the influence of the destination environment to dominate the influence of the source environment.
Partial characterization of proteinase activity in the larval midgut of the European corn borer, Ostrinia nubilalis Hübner (Lepidoptera: Pyralidae)
Authors: Houseman Jon G. , Philogène B. J. R. , Downe A. E. R.
Published: February 2008

Protease activity in the alimentary tract of the European corn borer, Ostrinia nubilalis, can be attributed to at least three endoproteinases. A high alkaline trypsin with maximal hydrolysis of benzoyl arginine p-nitroanilide at pH values higher than 10.0, a low alkaline trypsin with maximal activity against benzoyl arginine ethyl ester at pH 9.0, and chymotrypsin, which hydrolyzed benzoyl tryosine ethyl ester at pH 7.5–8.0, were detected in gut homogenates. Total proteolysis, measured using azocasein, had maximal activity at pH 10.0 or higher. Corn borer chymotryptic activity had characteristics similar to the vertebrate enzyme. Both tryptic activities differed from vertebrate trypsin by being insensitive to ovomucoid trypsin inhibitor. High and low alkaline trypsin differed from each other by their pH optima. High alkaline trypsin was activated by magnesium and calcium, and low alkaline trypsin was not affected by inclusion of either chemical in the assay mixture.
Dove reproduction and retinoid (vitamin A) dynamics in adult females and their eggs following exposure to 3,3′,4,4′-tetrachlorobiphenyl
Authors: Spear P. A. , Bourbonnais D. H. , Peakall D. B. , Moon T. W.
Published: February 2008

One week before mating, ring doves (Streptopelia risoria) received an intraperitoneal injection of vitamin-stripped corn oil containing 0 or 40 μg/g 3,3′,4,4′-tetrachlorobiphenyl. Of numerous reproductive parameters investigated, egg laying was retarded (p < 0.001) and 43% of the embryos died primarily between days 4 and 7 of incubation in the exposed group. Exposed females laying viable eggs had higher (p < 0.01) serum retinol at the time of mating than exposed females producing eggs that failed to develop to hatching. Serum retinol concentrations were greater (p < 0.05) in exposed males than in control males. A method was developed to extract and quantify five naturally occurring retinoids in egg yolks. When the experiment was repeated, yolk retinol and retinyl palmitate decreased (p < 0.05) between days 3 and 8 of development in the eggs of the exposed group regardless of embryo viability. No change in yolk retinoids occurred in the control group. At day 3 of incubation, the ratio of retinol: retinyl palmitate in yolks was greater (p < 0.01) in the viable eggs of the exposed group than in either the controls or the nonviable eggs of the exposed group. Despite the reproductive effects, the repeated dose of biphenyl did not elicit liver porphyrin accumulation or alter internal organ weights. Liver retinol concentrations were lower in males (p < 0.001) and females (p < 0.05) exposed to the toxicant than in controls; liver retinyl palmitate was unchanged. These changes in retinoid dynamics during oogenesis and in ovo may be a compensatory response to the toxicant.
Carcinonemertes regicides n.sp. (Nemertea), a symbiotic egg predator from the red king crab, Paralithodes camtschatica (Decapoda: Anomura), in Alaska
Authors: Shields Jeffrey D. , Wickham Daniel E. , Kuris Armand M.
Published: February 2008

A symbiotic nemertean worm, Carcinonemertes regicides n.sp., found on red king crabs, Paralithodes camtschatica, is described and compared with other members of the genus Carcinonemertes. The family Carcinonemertidae Humes, 1942 is emended to include this species and to include known but as yet undescribed members. The following familial characters are considered diagnostic: (i) symbiotic relationship with a decapod crustacean, (ii) short proboscis, (iii) absence of cerebral organs, (iv) presence of Takakura's duct, and (v) a hoplonemertean larva. The new species of Carcinonemertes has a relatively large basis and stylet, a large anterior proboscis chamber, and a newly described flame cell pattern of 2[(1 + 1 + 1 + 1)]. In addition, at maturity it is the smallest member of the genus (typical adult size is 2.0 mm in length), and female worms bear ovarian pores before oviposition. The above characters distinguish this species from others in the genus.
Dispersion of adult male Peromyscus leucopus in relation to female reproductive status
Authors: Xia Xuhua , Millar John S.
Published: February 2008

We studied dispersion of adult male Peromyscus leucopus in relation to the stage of pregnancy of adult females in natural populations monitored with Longworth live traps. Because postpartum mating is common in P. leucopus and days to parturition measures how far a female is from her next mating, we predicted that a female in early pregnancy (many days to parturition) would have fewer adult males in her neighbourhood than a female in late pregnancy (few days to parturition). Number of adult males caught within 30 m of each adult female was recorded and number of days to parturition for each female was obtained by bringing females back to the laboratory and allowing them to give birth. A negative relationship was found between number of adult males in a female's neighbourhood and days to parturition of the female (r = −0.419, p < 0.01), with the latter accounting for 8.8% of the variance in the former. These results support the hypothesis of a promiscuous mating system in P. leucopus.
Assessment and preliminary development of the rotating-jaw Conibear 120 trap to effectively kill marten (Martes americana)
Authors: Proulx Gilbert , Cook Stephen R. , Barrett Morley W.
Published: February 2008

Testing and development of the commercially available rotating-jaw Conibear 120 (C120) trap were conducted from January to June 1986 with wild marten (Martes americana) in simulated natural environments. Minimizing the pain and suffering of animals was a primary concern throughout the entire investigation. Through a series of approach tests involving traps wired in the set position, a pitch-fork style trigger was developed which enabled the trap to consistently strike animals in the head and neck region. The ability of the C120 to effectively kill marten was first assessed in preselection tests in which anaesthetized animals were placed in the trap in a position that duplicated the finding of the approach tests. Five out of six animals were rendered unconscious within 3 min. Thereafter, the ability of the C120 to effectively kill unanaesthetized marten was tested against that of a prototype, the C120 Mark IV, a more powerful modified version of the original model. The C120 failed to render unconscious at least five out of six unanaesthetized marten within 3 min and, by protocol, was rejected as an effective killing trap. The C120 Mark IV, with a metal bar welded on the top striking jaw, rendered five out of six marten unconscious within 3 min and qualified for further testing as a potentially effective trap to kill marten. Despite its wide use as a quick-kill trap, the C120 did not meet the performance criteria of this study. The mechanically upgraded C120 Mark IV outperformed the C120 but further improvements are needed to ensure consistently quick kills with marten.
Caligus elongatus (Copepoda: Caligoida) from Atlantic salmon (Salmo salar) cultured in marine waters of the Lower Bay of Fundy
Authors: Hogans W. E. , Trudeau Deborah J.
Published: February 2008

The occurrence of Caligus elongatus on Atlantic salmon (Salmo salar) cultured in marine waters in the Passamaquoddy Bay region of the lower Bay of Fundy is reported. Two size classes of cultured salmon (smolts and market size) were examined. Prevalence of C. elongatus was 54.5% on market fish and 54.7% on smolts. Intensities of infection for market fish and smolts were recorded as 2.41 and 2.58, respectively. Overall sex ratio of adult C. elongatus on infected salmon was 1:1.4 females to males; mean number of eggs per gravid female C. elongatus was 169.
Chloride uptake in isolated gills of the freshwater mussel Ligumia subrostrata
Authors: Dietz Thomas H. , Hagar Arthur F.
Published: February 2008

Isolated mussel gills accumulate chloride from the incubation medium at a rate sufficient to account for most of the whole-animal chloride uptake rate. The chloride influx was remarkably variable, ranging from 2 to 15 μmol/(g dry gill∙10 min). Chloride influx did not correlate with sodium influx. Chloride uptake displayed saturation kinetics with an affinity of 0.3 mM/L and a maximal influx of 10 μmol/(g dry gill∙10 min). Isolated mussel gill chloride influx is not regulated by cyclic AMP or cyclic GMP but is inhibited by thiocyanate, 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid, and nystatin.
A comparison of the reproductive behaviours of three Calopteryx species (Odonata: Calopterygidae) in Nova Scotia
Authors: Meek S. B. , Herman T. B.
Published: February 2008

Although repertoires were similar, duration of pair-forming and postcopulatory displays varied among three sympatric Calopteryx species in Nova Scotia. Preliminary ("cross") displays were shortest in C. maculata and longest in C. aequabilis, and were often omitted completely in C. amata. Courtships displays ("arcs") were briefest and least elaborate in C. maculata and most elaborate and protracted in C. amata. Courtship sequences were most successful (led to copulation) in C. aequabilis and least successful in C. amata, although males of this species were most persistent. Most female C. maculata oviposited at the surface, guarded by mates. Most female C. aequabilis were also guarded, but oviposited both above and below the surface. Female C. amata were commonly unguarded, and most oviposited below the surface. We suggest that an interaction between territorial and oviposition behaviours, influenced by resource abundance, modulates reproductive behaviour in Calopteryx species.
Predicting nutritional condition in black bears and polar bears on the basis of morphological and physiological measurements
Authors: Cattet Marc
Published: February 2008

Thirty-eight black bears (Ursus americanus) and 43 polar bears (Ursus maritimus) were dissected to determine equations for predicting body weight (BW) and nonfat body weight (NFBW). Nutritional condition was estimated by calculating a fat to nonfat (FNF) ratio, equalling (BW – NFBW)/NFBW. For each species, BW and NFBW were accurately predicted by multiple regression equations based on morphological measurements. The FNF ratio was independent of body size and thus comparable between sexes and among age-classes. The accuracy of predicting the FNF ratio is limited, and reliable comparisons of nutritional condition among individual bears will require the development of more accurate techniques. Physiological measurements of marrow and intramuscular percent lipid content were also evaluated as potential indicators of nutritional condition, but were determined to be unreliable.
Weather and Osprey foraging energetics
Authors: Machmer Marlene M. , Ydenberg Ronald C.
Published: February 2008

The influence of weather on the foraging behavior of breeding male Ospreys (Pandion haliaetus) was investigated from an energetic perspective. Neither cloud cover, sun brightness, nor precipitation had significant effects on foraging performance. Wind speed and water surface conditions both had an effect, and as expected, they were very highly correlated. As wind speed increased (and surface conditions deteriorated), Ospreys glided more and flapped less while hunting, but each hunt became longer and was less likely to terminate with capture of a fish. Wind speed was by far the strongest effect. Overall, more work was required to capture each prey as wind speed increased, and the data indicate that the detrimental effects increase sharply at wind speeds greater than about 7 m/s. The results are compared with previous investigations of Osprey foraging.