bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of age on the epidemiology of incomplete abortions in South Africa after legislative change
Authors: Jewkes Rachel , Rees Helen , Dickson Kim , Brown Heather , Levin Jonathan
Published: February 2005

Objective  In 1996 termination of pregnancy was legalised in South Africa. This article examines the impact of age on the epidemiology of incomplete abortion after legislative change. It draws comparison with the findings of a similar study undertaken in 1994.

Design  Multicentre, prospective, descriptive study.

Setting  Forty‐seven public hospitals in all nine provinces.

Sample  A stratified random sample of all hospitals treating gynaecological emergencies was drawn. All women of gestation under 22 weeks who presented with incomplete abortion during three weeks of data collection in 2000 were included.

Methods  A data capture sheet completed by a clinician from the case notes.

Main outcome measures  Demographic characteristics and clinical findings on admission by age of women.

Results  Overall, there was a significant increase in the proportion of cases with no signs of infection on admission (from 79.5% to 90.1%) and a significant decrease in evidence of interference on evacuation (4.5% to 0.6%) between 1994 and 2000. Substantial age differentials were seen. Women over 30 were significantly less likely than those 21–30 years or under 21 to be low severity (65.5%vs 75.2%vs 76.4%, P= 0.0087) and more likely to have offensive products (16.3%vs 6.0%vs 6.4%, P= 0.01) than the younger women.

Conclusions  Legalisation of abortion had an immediate positive impact on morbidity, especially in younger women. This is an important change as teenagers had the highest morbidity in 1994. The trend is supported by evidence from the 1999–2001 Confidential Enquiry into Maternal Deaths, which further suggested that abortion mortality dropped by more than 90% since 1994.
Association of raised titres of antibodies to Chlamydia pneumoniae with a history of pre‐eclampsia
Authors: Goulis Dimitrios G. , Chappell Lucy , Gibbs Richard G.J. , Williams David , Dave Jitendra R. , Taylor Paul , De Swiet Michael , Poston Lucilla , Williamson Catherine
Published: February 2005

Objective  To establish the prevalence of Chlamydia pneumoniae (C. pneumoniae) infection in a pregnant UK population and to investigate whether C. pneumoniae infection is more common in women with a previous history of pre‐eclampsia.

Design  Prospective study.

Setting  Academic Hospital.

Population  Ninety‐one pregnant women (54 parous and 37 nulliparous) at 16–22 weeks of gestation were studied. Of the parous women, 32 had a previous history of pre‐eclampsia.

Methods  Peripheral blood was drawn for C. pneumoniae antibodies between 16–22 and 28–40 weeks of gestation. C. pneumoniae antibodies were measured using a solid‐phase enzyme immunoassay. According to pregnancy outcome, women were categorised into normal, gestational hypertension and pre‐eclampsia groups.

Main outcome measures  Serum levels of IgG, IgA and IgM C. pneumoniae antibodies.

Results  Prevalence of seropositivity to C. pneumoniae was 77%. Parous women had significantly higher levels of IgA and IgM C. pneumoniae antibodies than nulliparous women (P < 0.04). Parous women with previous pre‐eclampsia were found to have higher levels of antibodies than parous women with a normal obstetric history (P≤ 0.003). There was no difference in the antibody levels in women with different pregnancy outcomes.

Conclusions  The longitudinal data do not indicate an association between C. pneumoniae infection and pre‐eclampsia. However, the subgroup analysis of parous women demonstrated raised C. pneumoniae antibodies in the women with previous pre‐eclampsia, and therefore suggests that there may be an association between C. pneumoniae and the disease in this group.
Bladder neck mobility is a heritable trait
Authors: Dietz H.P. , Hansell N.K. , Grace M.E. , Eldridge A.M. , Clarke B. , Martin N.G.
Published: February 2005

Objective  Congenital connective tissue dysfunction may partly be responsible for female pelvic organ prolapse and urinary incontinence. We undertook a heritability study to determine whether mobility of the bladder neck, one of the main determinants of stress urinary incontinence, is genetically influenced.

Design  Heritability study using a twin model and structural equation modelling.

Setting  Queensland Institute of Medical Research, Brisbane, Australia.

Population  One hundred and seventy‐eight nulliparous Caucasian female twins and their sisters (46 monozygotic pairs, 24 dizygotic pairs and 38 sisters) aged 18–24 years.

Methods  We performed translabial ultrasound, supine and after bladder emptying, for pelvic organ mobility. Urethral rotation and bladder neck descent were calculated using the best of three effective Valsalva manoeuvres.

Main outcome measures  Bladder and urethral mobility on Valsalva assessed by urethral rotation, vertical and oblique bladder neck descent.

Results  Genetic modelling indicated that additive genes accounted for up to 59% of the variance for bladder neck descent. All remaining variance appeared due to environmental influences unique to the individual, including measurement error.

Conclusion  A significant genetic contribution to the phenotype of bladder neck mobility appears likely.
Reducing blood loss at open myomectomy using triple tourniquets: A randomised controlled trial
Authors: Taylor A. , Sharma M. , Tsirkas P. , Di Spiezio Sardo A. , Setchell M. , Magos A.
Published: February 2005

Objectives  To evaluate triple tourniquets in controlled conditions and for the first time to investigate the hypothesis that leaving a semi‐permanent tourniquet around the uterine artery reduces post‐operative bleeding from the uterine incisions.

Design  A randomised controlled trial.

Setting  Two University teaching hospitals.

Population  Twenty‐eight patients with symptomatic fibroids and uterine sizes ranging from 14 to 24 weeks of gestation undergoing open myomectomy.

Methods  A number 1 polyglactin suture was tied around the cervix to occlude the uterine arteries, and polythene tourniquets were tied around the infundibulopelvic ligament to obstruct the ovarian vessels. At the end of the procedure, the ovarian ties were released but the uterine artery suture remained in situ.

Main outcome measures  Intra‐operative blood loss, post‐operative blood loss, blood transfusion rates, operative morbidity, uterine blood flow and ovarian function.

Results  There was significantly less blood lost in the tourniquet group than in the control group (difference between means 1870 mL, 95% CI 1159–2580 mL, P < 0.0001; transfusion rates of 7% and 79%, P= 0.0003). The volume in the pelvic drain 20 min post‐operatively and after 48 hours failed to reach statistical significance between the two groups (P= 0.10 and P= 0.165). There were no differences in uterine artery Doppler resistance indices at five days (P= 0.54), six weeks (P= 0.47), three months (P= 0.49) and at six months (P= 0.18). Day two serum FSH concentrations after surgery were unchanged (P= 0.45), compared with baseline values.

Conclusions  Triple tourniquets are effective in reducing bleeding and transfusion rates. There appears no obvious adverse effect on uterine perfusion or ovarian function.
Maternal and paternal thrombophilia: risk factors for perinatal mortality
Authors: de Galan‐Roosen Agnes E.M. , Kuijpers Johan C. , Rosendaal Frits R. , Steegers Eric A. , van Beers Wil A. , Ponjee Gabriëlle A. , Merkus Hans M.
Published: February 2005

Background  Although some paternal components to the predisposition to pre‐eclampsia have been demonstrated recently, it is not known whether such paternal factors play a role to thrombophilia‐related perinatal mortality.

Objective  To compare the paternal and maternal contribution to perinatal mortality.

Study design  Data from a prospective registry of perinatal mortality in a Dutch healthcare region were used. Between December 1999 and May 2000, the prevalence of thrombophilia was studied in 74 women with a history of perinatal mortality (female cases) and 54 of their male partners (male cases). Seventy‐one healthy unrelated women after uneventful pregnancies only and 66 of their male partners were used as controls.

Setting  Obstetric outpatient clinic in a regional hospital (Remierde Graaf Group, Deflt).

Methods  Presence of various coagulation abnormalities, hyperhomocysteinaemia and anticardiolipins was investigated.

Results  The frequency of antithrombin deficiency (12%vs 0%), increased activated protein C (APC) resistance (32%vs 6%), total protein S deficiency (11%vs 1%) and elevated factor VIII:C activity (43%vs 17%) was significantly higher in female cases compared with controls. In male cases, the frequency of increased APC resistance was significantly higher compared with controls (22%vs 0%). In 30 of the 54 couples with a history of perinatal mortality, more than one thrombophilic abnormality was found (55%) compared with 10 of the 62 control couples (17%).

Conclusion  The risk of having thrombophilia is doubled in men who have fathered pregnancies which ended in perinatal death as well as in the mothers of such pregnancies.
The significance of intrauterine lesions detected by ultrasound in asymptomatic postmenopausal patients
Authors: Lev‐Sagie Ahinoam , Hamani Yaron , Imbar Tal , Hurwitz Arye , Lavy Yuval
Published: February 2005

A retrospective study on 82 women with an incidental sonographic finding suspected to be intrauterine polyps was undertaken to assess the histopathologic characteristics of such polyps utilising operative hysteroscopy. Endometrial polyps were found in 68 patients, submucousal myomas in 7, atrophic endometrium in 6 and thickened proliferative endometrium was found in 1 patient. Simple hyperplasia was found in one polyp but neither endometrial carcinoma nor complex hyperplasia was found. The total complication rate was 3.6%. It appears that the risk of endometrial carcinoma in postmenopausal women with asymptomatic endometrial polyps is low, although a larger series is required to confirm this finding.
Variations in vaginal and abdominal hysterectomy by region and trust in England
Authors: Bottle Alex , Aylin Paul
Published: February 2005

Objective  To examine variations between regions and hospitals in the proportion of hysterectomies performed abdominally.

Design  Analysis of routine hospital data.

Setting  All National Health Service hospitals in England.

Population  Women aged 18+ hospitalised between April 1998 and March 2001.

Methods  Logistic regression, adjusting for age and diagnosis.

Main outcome measure  Use of the abdominal rather than the vaginal route.

Results  The adjusted proportion of hysterectomies performed abdominally varied from 75–89% between regions, and from 25–99% between hospitals. Diagnosis accounted for nearly a third of the total variation, dwarfing the contributions of age and hospital. About two‐thirds of the variation remained unaccounted for.

Conclusion  Despite evidence suggesting that the majority of hysterectomies may be performed vaginally, very few English trust match this.
Identification of microsatellite markers in a neotropical seasonally dry forest tree, Astronium urundeuva (Anacardiaceae)
Authors: CAETANO S. , SILVEIRA P. , SPICHIGER R. , NACIRI‐GRAVEN Y.
Published: February 2005

Nine dinucleotide microsatellites were developed in Astronium urundeuva (Anacardiaceae), a typical tree of the seasonally‐dry tropical forests of South America and characterized on three populations from Paraguay and Argentina. Seven microsatellites were found polymorphic in within population gene diversities ranging from 0.32 to 0.91, and an observed number of alleles varying between four and 20. Despite their relatively low number of alleles, these markers proved valuable tools in detecting genetic structure between three populations in Paraguay and North Argentina.
Isolation of new microsatellite loci from the Green Lizard (Lacerta viridis viridis)
Authors: BÖHME M. U. , BERENDONK T. U. , SCHLEGEL M.
Published: February 2005

Twelve new microsatellite loci were isolated from the Green Lizard (Lacerta viridis viridis). Primers for 28 loci were designed and 18 of these loci amplified well for 10 individuals of four populations. Twelve of these loci were further characterized for a population in Hungary. The results document the suitability of these identified loci for the characterization of the genetic diversity of the endangered species L. viridis viridis.
Felid sex identification based on noninvasive genetic samples
Authors: PILGRIM K. L. , MCKELVEY K. S. , RIDDLE A. E. , SCHWARTZ M. K.
Published: February 2005

We developed two tests for sex identification of felids using y‐chromosome deletions in the zinc‐finger and amelogenin regions. These tests provide positive results for both males and females, while reducing the need to co‐amplify microsatellites to test for DNA quality in hair and scat samples. Furthermore, the y‐chromosome deletions are absent in a wide‐range of prey species; thus, when these tests are used on scat samples, potential contamination caused by prey DNA incidentally extracted, is minimized.
New microsatellite markers in turbot (Scophthalmus maximus) derived from an enriched genomic library and sequence databases
Authors: PARDO G. B. , CASAS L. , FORTES G. G. , BOUZA C. , MARTÍNEZ P. , CLARK M. S. , SÁNCHEZ L.
Published: February 2005

Scophthalmus maximus is an important commercially aquaculture fish species. We tackle the search for new microsatellites using two different approaches: an enriched partial genomic library and a screening of all turbot DNA sequences deposited in GenBank. Out of 15 genomic library derived loci, five gave working primer pairs, with expected heterozygosities (HE) ranging from 0.13 to 0.91. Out of seven loci derived from database sequences, two amplified successfully with an HE ranging from 0.56 to 0.63. The average allele number of these microsatellites was 5.7 per locus with a range between two and 15.
New polymorphic microsatellite markers for California sea lions (Zalophus californianus)
Authors: HERNANDEZ‐VELAZQUEZ F. D. , GALINDO‐SANCHEZ C. E. , TAYLOR M. I. , DE LA ROSA‐VELEZ J. , COTE I. M. , SCHRAMM Y. , AURIOLES‐GAMBOA D. , RICO C.
Published: February 2005

Nine microsatellite loci were isolated and characterized from California sea lions (Zalophus californianus). In addition, two of five loci tested from harbour seal (Phoca vitulina) produced a single, clear band in Z. californianus, as did one out of five loci from grey seal (Halichoerus grypus) and one out of two loci from elephant seal (Mirounga sp.). No locus tested from South American fur seal (Arctocephalus australis) amplified in Z. californianus. Locus variability was assessed in California sea lions from Los Islotes rookery, Baja California Sur, Mexico. All loci were variable, with allele numbers ranging from three to 12.
Characterization of new microsatellite loci for the ring‐tailed lemur (Lemur catta)
Authors: PASTORINI J. , FERNANDO P. , FORSTNER M. R. J. , MELNICK D. J.
Published: February 2005

In this report we describe the development and characterization of six dinucleotide microsatellite loci for the ring‐tailed lemur (Lemur catta). The new markers were isolated from the genomic DNA of L. catta and all loci were found to be polymorphic when evaluated by genotyping a minimum of 34 individuals. Mendelian inheritance of each locus was verified using four families of captive ring‐tailed lemurs. The loci presented will facilitate the genetic survey of free‐ranging L. catta, enabling study of their social organization and mating patterns.
Microsatellite DNA markers for the study of Atlantic salmon (Salmo salar) kinship, population structure, and mixed‐fishery analyses
Authors: KING TIM L. , EACKLES MICHAEL S. , LETCHER BENJAMIN H.
Published: February 2005

Eleven microsatellite DNA loci were identified and characterized for Atlantic salmon (Salmo salar) collected from the Penobscot River, Maine, USA and the River Nith, Scotland, UK. The markers revealed high levels of genetic diversity (seven to 48 alleles per locus), heterozygosity (to 100%), and allelic heterogeneity (all comparisons). Considerable differentiation was observed as the genetic distance (chord) between the two collections was 0.680 and the pairwise FST, 0.12, was highly significant. These findings are consistent with patterns of continental‐level differentiation observed previously using an alternate suite of microsatellite loci. Locus‐by‐locus analyses of molecular variance suggested that most markers were suitable for delineating kinships and population genetic structure.
Microsatellite DNA markers for the study of population structure and dynamics in nutria (Myocastor coypus)
Authors: CALLAHAN COLLEEN R. , HENDERSON ANNE P. , EACKLES MICHAEL S. , KING TIM L.
Published: February 2005

We document the isolation and characterization of 27 microsatellite DNA markers for nutria, or coypu (Myocastor coypus), an invasive rodent introduced to North America as a domestic furbearer. Markers revealed moderate levels of diversity (averaging 5.0 alleles/locus) and heterozygosity (averaging 46%). Genotypic frequencies at 25 of 27 (93%) markers conformed to Hardy–Weinberg equilibrium expectations and no linkage disequilibrium was observed in a M. coypus collection (N = 64) from Maryland, USA. We believe this suite of markers to yield sufficient diversity to resolve patterns of effective migration among subpopulations, breeding structure, and demographics. This information can be instrumental to eradication programs that attempt to prevent recolonization among subpopulations.
Two contrasted P–T–time paths of coronitic metanorites of the French Massif Central: are reaction textures reliable guides to metamorphic histories?
Authors: NICOLLET C. , GONCALVES P.
Published: February 2005

Metanorites from two eclogitized metagabbros of the Hercynian French Massif Central preserve coronitic textures of hornblende, garnet, quartz and/or kyanite produced at the expense of the primary magmatic assemblage orthopyroxene and plagioclase. Using a petrogenetic grid in the CFMASH system, two possible P–T evolutions for the origin of the coronas are evaluated. The sequence of reactions involving the formation of Hbl (–Ky) ± Grt and Qtz coronitic assemblages is consistent with an isobaric cooling at high pressure (c. 1–2 GPa) under hydrated conditions. However, this P–T path, inferred by using only petrographical observations, is inconsistent with the geochronological constraints: emplacement of the gabbro at 490 Ma and high‐pressure metamorphism at 410 Ma. In order to reconcile petrographical observations with geochronological constraints, we propose a discontinuous two‐stage evolution involving a change in water activity with time. (1) Emplacement and cooling of the norite at low pressure under anhydrous conditions, at 490 Ma. (2) During the Hercynian orogeny, the norite experienced an increase in pressure and temperature under fluid‐present conditions. Adding water to the system implies a dramatic change in the petrogenetic grid topology, restricting the orthopyroxene–plagioclase assemblage only to high temperatures. Therefore, the breakdown of the unstable magmatic assemblage, through apparent retrograde reactions, occurred along the prograde P–T path which never crossed the equilibrium boundaries of these reactions.
Kinetic and binding studies with purified recombinant proteins ferredoxin reductase, ferredoxin and cytochrome P450 comprising the morpholine mono‐oxygenase from Mycobacterium sp. strain HE5
Authors: Sielaff Bernhard , Andreesen Jan R.
Published: February 2005

The P450mor system from Mycobacterium sp. strain HE5, supposed to catalyse the hydroxylation of different N‐heterocycles, is composed of three components: ferredoxin reductase (FdRmor), Fe3S4 ferredoxin (Fdmor) and cytochrome P450 (P450mor). In this study, we purified Fdmor and P450mor as recombinant proteins as well as FdRmor, which has been isolated previously. Kinetic investigations of the redox couple FdRmor/Fdmor revealed a 30‐fold preference for the NADH‐dependent reduction of nitroblue tetrazolium (NBT) and an absolute requirement for Fdmor in this reaction, compared with the NADH‐dependent reduction of cytochrome c. The quite low Km (5.3 ± 0.3 nm) of FdRmor for Fdmor, measured with NBT as the electron acceptor, indicated high specificity. The addition of sequences providing His‐tags to the N‐ or C‐terminus of Fdmor did not significantly alter kinetic parameters, but led to competitive background activities of these fusion proteins. Production of P450mor as an N‐terminal His‐tag fusion protein enabled the purification of this protein in its spectral active form, which has previously not been possible for wild‐type P450mor. The proposed substrates morpholine, piperidine or pyrrolidine failed to produce substrate‐binding spectra of P450mor under any conditions. Pyridine, metyrapone and different azole compounds generated type II binding spectra and the Kd values determined for these substances suggested that P450mor might have a preference for more bulky and/or hydrophobic molecules. The purified recombinant proteins FdRmor, Fdmor and P450mor were used to reconstitute the homologous P450‐containing mono‐oxygenase, which was shown to convert morpholine.
Intracavernosal Irrigation by Cold Saline as a Simple Method of Treating Iatrogenic Prolonged Erection
Authors: Ateyah Ahmed , Rahman El-Nashar Abdel , Zohdy Wael , Arafa Mohammed , Saad El-Den Hatem
Published: February 2005

Aims and Methods

The aim of this study was to evaluate the efficacy of aspiration and irrigation of the corpora cavernosa with cold saline as a simple outpatient method for treating prolonged penile erection after intracavernous injection of vasoactive agents.

Results

Aspiration and irrigation was needed in 70 out of 122 cases with iatrogenic priapism in whom cooling of the penis and perineum failed to achieve detumescence. According to the temperature of the saline used, patients were randomized into four different groups: A, B, C, and D with a saline temperature 10, 15, 20, and 37°C, respectively.

Main Outcome

We used a significantly larger volume of saline in groups C and D compared to group A. On the other hand there was no significant difference in the volume of saline used between groups A and B. Complete detumescence was achieved in 24/25 (96%) of cases in group A compared to 9/15 (60%) of cases in group D.

Conclusion

We recommend corporal aspiration and irrigation with 10°C saline for patients with prolonged penile erection who failed to respond to the noninvasive measures using ice-cold compresses and physical exercise.
Analysis of Active Joint Failure in Parallel Robot Manipulators
Authors: Hassan Mahir , Notash Leila
Published: February 2005

In this study, the effect of active joint failure on the mobility, velocity, and static force of parallel robot manipulators is investigated. Two catastrophic active joint failure types are considered: joint jam and actuator force loss. To investigate the effect of failure on mobility, the Gru¨bler’s mobility equation is modified to take into account the kinematic constraints imposed by various branches in the manipulator. In the case of joint jam, the manipulator loses the ability to move and apply force in a specific portion of its task space; while in the case of actuator force loss, the manipulator gains an unconstrained motion in a specific portion of the task space in which an externally applied force cannot be resisted by the actuator forces. The effect of joint jam and actuator force loss on the velocity and on the force capabilities of parallel manipulators is investigated by examining the change in the Jacobian matrix, its inverse, and transposes. It is shown that the reduced velocity and force capabilities after joint jam and loss of actuator force could be determined using the null space vectors of the transpose of the Jacobian matrix and its inverse. Computer simulation is conducted to demonstrate the application of the developed methodology in determining the post-failure trajectory of a 3-3 six-degree-of-freedom Stewart-Gough manipulator, when encountering active joint jam and actuator force loss.
Graphical Technique to Locate the Center of Curvature of a Coupler Point Trajectory
Authors: Pennock Gordon R. , Kinzel Edward C.
Published: February 2005

This paper presents an original technique to locate the center of curvature of the path traced by an arbitrary point fixed in the coupler link of a planar four-bar linkage. The method is purely graphical and the center of curvature; i.e., the center of the osculating circle, can be located in a direct manner with few geometric constructions. The advantage of this technique, compared to the classical approach using the Euler-Savary equation, is that measurements of angles and distances between points are not required. Also, it is not necessary to locate inflection points or draw the inflection circle for the instantaneous motion of the coupler link. The technique is based on the concept of a virtual link which is valid up to, and including, the second-order properties of motion of the coupler link. The virtual link is coincident with the path normal to the coupler curve; i.e., the line connecting the coupler point to the velocity pole of the coupler link. The absolute instant center of the virtual link defines the ground pivot for the link and is, therefore, coincident with the center of the osculating circle. The authors believe that the graphical approach presented in this paper represents an important contribution to the kinematics literature on the curvature of a point trajectory.
Design of a Passively Balanced Spatial Linkage Haptic Interface
Authors: Steger R. , Lin K. , Adelstein B. D. , Kazerooni H.
Published: February 2005

This paper describes the design and implementation of a compact high fidelity desktop haptic interface that provides three-degree-of-freedom point-force interaction through a handheld pen-like stylus. The complete haptic device combines a spatial linkage, actuation, power amplification, and control electronics in a standalone package with a footprint similar to that of a notebook computer 33cm×25cm×10cm. The spatial linkage is composed of one planar and two spherical subloops. Two versions of the spatial linkage were designed: a lightweight polycarbonate plastic version suitable for inexpensive mass production, and an aluminum and stainless steel linkage that offers greater reliability and higher stiffness. Both linkages were designed to be statically balanced over their full workspace.
Synthesis, Design, and Prototyping of a Planar Three Degree-of-Freedom Reactionless Parallel Mechanism
Authors: Foucault Simon , Gosselin Cle´ment M.
Published: February 2005

This paper addresses the dynamic balancing of a planar three-degree-of-freedom parallel mechanism. A mechanism is said to be dynamically balanced if, for any motion of the mechanism, the reaction forces and torques at the base are identically equal to zero, at all times. The proposed mechanism is based on legs consisting of five-bar parallelogram linkages. The balancing equations are first obtained. Then, optimization is used in order to minimize the mass and inertia of the moving links. Finally, a numerical verification of the dynamic balancing is provided and the prototype is presented.
Fast Three-Dimensional Quasi-Static Analysis of Helical Gears Using the Finite Prism Method
Authors: Guingand M. , de Vaujany J. P. , Icard Y.
Published: February 2005

This paper describes a model for analyzing external and internal helical gears. The finite prism method is used to study the elastic behavior of the structure. Contact deformations are also included in the model. Load sharing, pressure distribution, meshing stiffness and three-dimensional tooth fillet stresses are calculated at each instant. An experimental validation of the numerical model is also presented.
A Simple Procedure for Modifying High-Speed Cam Profiles for Vibration Reduction
Authors: Andresen Ulf , Singhose William
Published: February 2005

Unwanted vibration in cam-follower systems causes increased forces, noise, wear, and operating costs. This paper investigates the use of input shaping on cam profiles to reduce vibration. Input shaping is a real-time command modification algorithm developed for computer-controlled machines. In order to apply the concept to cam design, some modifications to the algorithm must be made. To test the validity of high-speed input-shaped cam profiles, an experimental apparatus was constructed with variable operating speeds and follower dynamics. The experimental results demonstrate the effectiveness of the proposed solution.
Scenario-Based Failure Modes and Effects Analysis Using Expected Cost
Authors: Kmenta Steven , Ishii Koshuke
Published: February 2005

Failure modes and effects analysis (FMEA) uses the product of three ranked factors to compute the risk priority number (RPN). Unfortunately, the RPN components have ambiguous definitions, and multiplying ranked values is not a valid operation. As a result, the RPN produces inconsistent risk priorities. In addition, FMEA uses distinct analyses for each system level and life cycle phase, making it difficult to consolidate interrelated risk information. The goal of scenario-based FMEA is to delineate and evaluate risk events more accurately. Probability and cost provide a consistent basis for risk analysis and decision making, and failure scenarios provide continuity across system levels and life cycle phases.
Conceptual Design of a Long-Strike Ultra-Precision Actuator
Authors: Gong Shao Wei
Published: February 2005

A conceptual long-strike ultra-precision actuator is proposed with this article. The design method is inspired by the unique relationship of voltage versus displacement with a coil-wound potentiometer. As an example, an embodiment of a novel two-stage actuator is built based on the method. The theoretical error analysis demonstrates that the actuator can achieve low double-digit nanometer actuating accuracy over a long-strike range. Some other advantages, such as fast actuating speed, automatic control, and cost effectiveness, are also expected.
A General Method for the Modeling of Spindle-Bearing Systems
Authors: Cao Yuzhong , Altintas Yusuf
Published: February 2005

In this paper we outline a general method that can be used to model spindle assembly, which consists of spindle shaft, angular contact ball bearings and housing. The spindle shaft and housing are modeled as Timoshenko’s beam by including the centrifugal force and gyroscopic effects. The bearing is modeled as a standard nonlinear finite element based on Jones’ bearing model that includes the centrifugal force and gyroscopic effects from the rolling elements of bearings. By applying cutting forces to the spindle for a given preload, the stiffness of the bearings, contact forces on bearing balls, natural frequencies, time history response, and frequency response functions of the spindle assembly can be evaluated. In the paper we provide details of the mathematical model supported by experimental results obtained from an instrumented test spindle.
On Rationality in Engineering Design
Authors: Franssen Maarten , Bucciarelli Louis L.
Published: February 2005

Rationality has different meanings within different contexts. In engineering design, to be rational usually means to be instrumentally rational, that is, to take a measured decision aimed at the realization of a particular goal, as in attempts to optimize an objective function. But in many engineering design problems, especially those that involve several engineers collaborating on a design task, there is no obvious or uncontested, unique objective function. An alternative approach then takes the locus of optimization to be individual engineers’ utility functions. In this paper, we address an argument which claimed that unless the engineers hold a common utility function over design alternatives, a suboptimal, hence, irrational, design is bound to ensue. We challenge this claim and show that, while sticking to the utility-function approach but adopting a game-theoretic perspective, rational outcomes to the problem at issue are possible.
A Hybrid Fuzzy Simplex Genetic Algorithm
Authors: Trabia Mohamed B.
Published: February 2005

This paper presents a novel hybrid genetic algorithm that has the ability of the genetic algorithms to avoid being trapped at local minimum while accelerating the speed of local search by using the fuzzy simplex algorithm. The new algorithm is labeled the hybrid fuzzy simplex genetic algorithm (HFSGA). Standard test problems are used to evaluate the efficiency of the algorithm. The algorithm is also applied successfully to several engineering design problems. The HFSGA generally results in a faster convergence toward extremum.
Development and Analysis of a Long-Stroke Spring Guiding System
Authors: Huang Kuang-Yuh , Ho Chi-hwa
Published: February 2005

Inspired by the operating principle of a tank’s track, we have developed a long-stroke spring guiding system with belt-shaped springs. Other than those characteristics of normal spring guides, the long-stroke spring guiding system has longer guided stroke and adjustable recovery force. To study the mechanical characteristics of the system, experiments and analyses are carried out. The finite element analysis software ABAQUS is applied to analyze the stress and the recovery force of the preloaded spring guiding during the guiding process, and the Buckingham pi theorem is utilized to investigate the complicated relationships among the geometric parameters, the working parameters, and the guiding properties. According to the analytical and experimental results, an efficient design process and design criteria for the guiding system are concluded and practically validated. Moreover, the system can be easily scaled down or modified to adapt to the applications in precision systems and microsystems due to its simple form and great variability.
A Study of Fuel Efficiency and Emission Policy Impact on Optimal Vehicle Design Decisions
Authors: Michalek Jeremy J. , Papalambros Panos Y. , Skerlos Steven J.
Published: February 2005

Recent environmental legislation, such as the European Union Directive on End-of-Life Vehicles and the Japanese Home Electric Appliances Recycling law, has had a major influence on product design from both an engineering and an economic perspective. This article presents a methodology for studying the effects of automobile fuel efficiency and emission policies on the long-term design decisions of profit-seeking automobile producers competing in an oligopoly market. Mathematical models of engineering performance, consumer demand, and manufacturing costs are developed for a specific market segment, and game theory is utilized to simulate competition among firms to predict design choices of producers at market equilibrium. Several policy scenarios are evaluated for the small car market, including corporate average fuel economy (CAFE) standards, carbon dioxide CO2 emissions taxes, and diesel technology quotas. The results indicate that leveraging CO2 taxes on producers for expected life cycle emissions yields diminishing returns on fuel efficiency improvement per regulatory dollar as the taxes increase, while CAFE standards achieve higher average fuel efficiency per regulatory dollar. Results also indicate that increasing penalties for violation of CAFE standards can result in lower cost to producers and consumers because of the effects of competition, and penalties based on fuel economy or emissions alone may not be sufficient incentive for producers to bring more costly alternative fuel vehicles into the market. The ability to compare regulations and achieve realistic trends suggests that including engineering design and performance considerations in policy analysis can yield useful predictive insight into the impact of government regulations on industry, consumers, and the environment.
Finding the Shortest Path on a Polyhedral Surface and Its Application to Quality Assurance of Electric Components
Authors: Kageura Masaru , Shimada Kenji
Published: February 2005

This paper presents a computational method for finding the shortest path along polyhedral surfaces. This method is useful for verifying that there is a sufficient distance between two electrical components to prevent the occurrence of a spark between them in product design. We propose an extended algorithm based on the Kanai-Suzuki method, which finds an approximate shortest path by reducing the problem to searching the shortest path on the discrete weighted graph that corresponds to a polyhedral surface. The accuracy of the solution obtained by the Kanai-Suzuki method is occasionally insufficient for our requirements in product design. To achieve higher accuracy without increasing the computational cost drastically, we extend the algorithm by adopting two additional methods: “geometrical improvement” and the “K shortest path algorithm.” Geometrical improvement improves the local optimality by using the geometrical information around a path obtained by the graph method. The K shortest path algorithm, on the other hand, improves the global optimality by finding multiple initial paths for searching the shortest path. For some representative polyhedral surfaces we performed numerical experiments and demonstrated the effectiveness of the proposed method by comparing the shortest paths obtained by the Chen-Han exact method and the Kanai-Suzuki approximate method with the ones obtained by our method.
A Kinematics and Power Flow Analysis Methodology for Automatic Transmission Planetary Gear Trains
Authors: Kahraman A. , Ligata H. , Kienzle K. , Zini D. M.
Published: February 2005

A generalized formulation for analyzing speeds and forces of the gear components of planetary automatic transmissions is proposed. The formulation is capable of analyzing any typical one-degree-of-freedom automatic transmission gear train containing any number of simple, compound or complex-compound planetary gear sets. The formulation consists of three components: a kinematic analysis formulation to compute rotational speeds of gears and carriers, a gear ratio and kinematic configuration search algorithm, and a power flow analysis formulation. The kinematics component computes rotational speeds of gears and carriers. Given the type and number of planetary gear sets, the search algorithm determines all possible kinematic configurations and gear tooth count combinations that result in a required set of gear ratios while eliminating all kinematic redundancies and unfavorable clutching sequences. The third component, the power-flow analysis formulation, performs a complete static force (power-flow) analysis to determine all gear and bearing forces and moments, and clutch and connection torque values. A five-speed transmission example is considered to highlight the capabilities of the proposed formulation.
Multi-Attribute Decision Making Using Hypothetical Equivalents and Inequivalents
Authors: See Tung-King , Gurnani Ashwin , Lewis Kemper
Published: February 2005

In this paper, the problem of selecting from among a set of alternatives using multiple, potentially conflicting criteria is discussed. A number of approaches are commonly used to make these types of decisions in engineering design, including pairwise comparisons, ranking methods, rating methods, weighted sum approaches, and strength of preference methods. In this paper, we first demonstrate the theoretical and practical flaws with a number of these commonly employed methods. We demonstrate the strengths and weaknesses of the various decision-making approaches using an aircraft selection problem. We then present a method based on the concept of hypothetical equivalents and expand the method to include hypothetical inequivalents. Visualization techniques, coupled with an indifference point analysis, are then used to understand the robustness of the solution obtained and determine the appropriate additional constraints necessary to identify a single robust optimal alternative. The same aircraft example is used to demonstrate the method of hypothetical equivalents and inequivalents.
Kinematics of the Translational 3-URC Mechanism1
Authors: Di Gregorio Raffaele
Published: February 2005

The use of less than six degrees of freedom (dof) mechanisms instead of six-dof ones is always recommended when the application makes it possible, since their architectures and control are simpler to manufacture and implement respectively. Three-dof mechanisms constitute an important subset of less-than-six-dof mechanisms, since either translational or spherical motion can be obtained through three-dof spatial mechanisms and many industrial applications require the only translational or spherical motion. This paper presents a new translational parallel mechanism (TPM), named translational 3-URC. The new mechanism belongs to the parallel architectures with 3-URC topology, which contain another architecture that is a spherical parallel wrist. The proposed TPM is not overconstrained and has three equal legs whose kinematic pairs are three revolute pairs and one passive cylindrical pair per leg. Its actuated pairs are three revolute pair located on the frame. The position and velocity analyses of the translational 3-URC will be addressed and solved. Its singularity conditions will be written in explicit form and geometrically interpreted.
Maternal and seasonal differences in egg sizes and spawning activity of northwest Atlantic haddock (Melanogrammus aeglefinus) in relation to body size and condition
Authors: Trippel Edward A , Neil Steven RE
Published: February 2005

Egg and larval production of 22 captive spawning pairs of northwest Atlantic haddock (Melanogrammus aeglefinus) were monitored. Females spawned an average of nine egg batches (range 316) with a mean batch fecundity of 60 000 eggs and mean total fecundity of 535 000 eggs. Mean spawning duration was 37 days with a mean batch interval of 5.4 days. In multiple linear regression, male Fulton's condition factor (range 1.101.55) and mean batch interval explained 56% of variation in fertilization rate (33% and 23%, respectively). Seasonal composite egg diameter spanned 1.371.53 mm among females. Mean egg diameter within females declined seasonally by an average of 10.4% (37% by volume). Females produced 46 larvae per gram body weight. Body weight was the single best predictor of fecundity (r2 = 0.57), with Fulton's condition factor (range 1.041.76) explaining no significant additional variation over length or weight. Length and condition explained 39% of variation in seasonal composite egg diameter (22% and 17%, respectively) and body weight independently explained 32%. Sex-specific parental condition and body size acted through large egg size and elevated fertility to enhance reproductive output. Male spawning success was more sensitive than egg production to changes in condition.
Basin-scale availability of salmonid spawning gravel as influenced by channel type and hydraulic roughness in mountain catchments
Authors: Buffington John M , Montgomery David R , Greenberg Harvey M
Published: February 2005

A general framework is presented for examining the effects of channel type and associated hydraulic roughness on salmonid spawning-gravel availability in mountain catchments. Digital elevation models are coupled with grain-size predictions to provide basin-scale assessments of the potential extent and spatial pattern of spawning gravels. To demonstrate both the model and the significance of hydraulic roughness, we present a scenario for optimizing the spatial extent of spawning gravels as a function of channel type in Pacific Northwest catchments. Predictions indicate that hydraulic roughness could control more than 65% of the potential available spawning habitat at our study sites. Results further indicate that bar roughness can be important for maintaining spawning gravels in lower mainstem reaches, while wood roughness may be required for spawning-gravel maintenance in steeper, upper mainstem channels. Our analysis indicates that wood loss and consequent textural coarsening could deplete up to one third of the potentially usable spawning area at our study sites.
Fishing and the impact of marine reserves in a variable environment
Authors: Rodwell Lynda D , Roberts Callum M
Published: February 2005

We use discrete-time models to investigate the impact of marine reserve establishment on fishery catch and biomass levels in open-access and quota-regulated fisheries under conditions of recruitment variability and natural mortality events. We find that under the conditions of variability tested, reserves can increase the probability of achieving target levels of biomass (60%, 35%, and 5% of carrying capacity) and can reduce catch variability in neighbouring fisheries, making future planning in the fishery more efficient. The size of the reserve required to meet each objective will depend on the initial condition of the stock and the exploitation rate in the fishery. Reserve coverage of between 20% and 40% prevent stock collapse in most cases. In heavily exploited fisheries, reserves are also likely to enhance mean catches, particularly in highly variable systems. If the stock has previously been heavily exploited, large reserves (≥60%) may be required to significantly increase the probability of achieving target biomass levels. However, once stocks have recovered, reserve coverage may be reduced without a reduction in this probability of success.
Predator-dependent functional responses and interaction strengths in a natural food web
Authors: Essington Timothy E , Hansson Sture
Published: February 2005

Predator-dependent functional responses decouple predation mortality from fluctuations in predator abundance and therefore can prevent strong "top-down" interaction strengths in food webs. We evaluated whether contrasts in the functional response of Baltic Sea cod (Gadus morhua) were consistent with the contrasting population dynamics of two prey species, herring (Clupea harengus) and sprat (Sprattus sprattus): sprat abundance increased nearly threefold following a sharp decline in the cod population (a strong interaction), whereas herring abundance failed to increase (a weak interaction). We found striking differences in the functional response of cod on alternative prey, and these were consistent with the observed patterns in interaction strengths. Cod predation was the dominant source of mortality for age-1 and age-2 sprat but was only important for age-1 herring. Moreover, the magnitude of predation mortality on age-1 and age-2 sprat was highly sensitive to cod biomass, whereas predation mortality on herring was only moderately sensitive to cod biomass. These analyses suggest the possibility that food webs are comprised of linkages that vary with respect to the magnitude and importance of predation mortality and how this mortality varies with changes in predator abundance.
Movements associated with home-range establishment by two species of lowland river fish
Authors: Crook David A
Published: February 2005

Individuals that occupy restricted home ranges for long periods have little chance to sample surrounding habitats and may only be able to respond to changes in the distribution of resources at very local scales. Processes leading to the selection of a home range, therefore, potentially have an important bearing on individual fitness and, ultimately, on population structure. In this study, movements associated with the establishment of home ranges by golden perch (Macquaria ambigua) and common carp (Cyprinus carpio) in an Australian lowland river were examined using radiotelemetry. To examine behaviour associated with exploration and settlement into new home ranges, fish were artificially translocated into an unfamiliar river section. Although there was substantial intraspecific variation in patterns of movement, all fish tracked over the entire study period eventually settled into restricted home ranges. Several fish of both species either moved away from established home ranges and settled in new areas, or undertook large-scale movements and subsequently returned to the original home range. It is suggested that such movements may provide a mechanism by which fish can reap the benefits of home-range occupation whilst still being able to respond to changes in the distributions of spatially and temporally dynamic resources.