bluuebunny/crossref_metadata_2025 huggingface dataset:
Implant Experience with an Implantable Hemodynamic Monitor for the Management of Symptomatic Heart Failure
Authors: STEINHAUS DAVID , REYNOLDS DWIGHT W. , GADLER FREDRIK , KAY G. NEAL , HESS MIKE F. , BENNETT TOM ,   For The Chronicle Investigators
Published: August 2005

Introduction: Management of congestive heart failure is a serious public health problem. The use of implantable hemodynamic monitors (IHMs) may assist in this management by providing continuous ambulatory filling pressure status for optimal volume management.

Methods and Results: The Chronicle® system includes an implanted monitor, a pressure sensor lead with passive fixation, an external pressure reference (EPR), and data retrieval and viewing components. The tip of the lead is placed near the right ventricular outflow tract to minimize risk of sensor tissue encapsulation. Implant technique and lead placement is similar to that of a permanent pacemaker. After the system had been successfully implanted in 148 patients, the type and frequency of implant‐related adverse events were similar to a single‐chamber pacemaker implant. R‐wave amplitude was 15.2 ± 6.7 mV and the pressure waveform signal was acceptable in all but two patients in whom presence of artifacts required lead repositioning. Implant procedure time was not influenced by experience, remaining constant throughout the study.

Conclusion: Based on this evaluation, permanent placement of an IHM in symptomatic heart failure patients is technically feasible. Further investigation is warranted to evaluate the use of the continuous hemodynamic data in management of heart failure patients.
Atypical Proarrhythmia with Dofetilide: Monomorphic VT and Exercise‐Induced Torsade de Pointes
Authors: REIFFEL JAMES A.
Published: August 2005

Proarrhythmia with dofetilide has most typically taken the form of torsade de pointes (TdP) and generally occurs early with therapy, such that in‐hospital initiation of dofetilide with 3 days of continuous electrocardiogram monitoring is recommended.

This article reports two unusual variants of ventricular proarrhythmia with dofetilide: (1) nonsustained runs of monomorphic ventricular tachycardia shortly after taking the first dose of dofetilide, confirmed by rechallenge; and (2) TdP that followed the development of isolated ventricular premature beats during an exercise test in a patient with neither excessive QT prolongation on dofetilide nor any ectopy whatsoever during in‐hospital telemetric monitoring but with significant QT interval prolongation after the postectopic pause.

These cases demonstrate that clinicians must be alert to the appearance of proarrhythmia with dofetilide at times other than early during drug initiation if the electrophysiological milieu is altered during nonhospital activity and/or of a pattern other than TdP.
Invasive Optimization of Cardiac Resynchronization Therapy: Role of Sequential Biventricular and Left Ventricular Pacing
Authors: KURZIDIM KLAUS , REINKE HEINRICH , SPERZEL JOHANNES , SCHNEIDER HANS JÜRGEN , DANILOVIC DEJAN , SIEMON GREGOR , NEUMANN THOMAS , HAMM CHRISTIAN W. , PITSCHNER HEINZ‐FRIEDRICH
Published: August 2005

Background: Aim of this invasive study was to characterize and quantify changes in left ventricular (LV) systolic function due to sequential biventricular pacing (BV) as compared to right atrial triggered simultaneous BV (BV0), LV, and right ventricular (RV) pacing in patients with congestive heart failure (CHF).

Methods: In 22 CHF patients, all in sinus rhythm, temporary multisite pacing was performed prior to implantation of a permanent system. LV systolic function was evaluated invasively by the maximum rate of LV pressure increase (dP/dtmax). Sequential BV pacing was performed with preactivation of either ventricle at 20–80 ms.

Results: In comparison to RV pacing, LV and BV0 pacing increased dP/dtmax by 33.9 ± 19.3% and 34.0 ± 22.6%, respectively (P < 0.001). In 9 patients, optimized sequential BV pacing further improved dP/dtmax by 8.5 ± 4.8% compared to BV0 (range 3.3–17.1, P < 0.05). In 10 patients exhibiting a PR interval ≤200 ms, LV pacing was either superior (n = 6) or equal to BV0 pacing (n = 4). In these 10 patients, LV pacing yielded a 7.4 ± 8.0% higher dP/dtmax than BV0 pacing (P < 0.05).

Conclusions: Using sequential BV pacing, generally with LV preactivation, moderate improvements in LV systolic function can be achieved in selected patients. Baseline PR interval may aid in the selection of the optimum cardiac resynchronization therapy (CRT) mode, favoring LV pacing in patients with a PR interval ≤200 ms.
Arrhythmic Storm Responsive to Quinidine in a Patient with Brugada Syndrome and Vasovagal Syncope
Authors: MÁRQUEZ MANLIO F. , RIVERA JAIME , HERMOSILLO ANTONIO G. , ITURRALDE PEDRO , COLÍN LUIS , MORAGREGA JOSÉ LUIS , CÁRDENAS MANUEL
Published: August 2005

A 37‐year‐old man with Brugada syndrome (BrS) and arrhythmic storm is described. One month after implantation of a cardioverter‐defibrillator he presented with recurrent appropriate shocks for spontaneous ventricular fibrillation (VF). Because of this arrhythmic storm, quinidine therapy was initiated with total suppression of all spontaneous arrhythmias. He had remained free of arrhythmias for 22 months since quinidine initiation. Two episodes of VF occurred after the patient stopped taking the medication. The patient resumed quinidine and has been free of VF for the last 3 months. This response to quinidine in a patient with symptomatic BrS supports its role in the prophylaxis of arrhythmic events in BrS.
The Effect of Anodal Stimulation on V‐V Timing at Varying V‐V Intervals
Authors: VAN GELDER BERRY M. , BRACKE FRANK A. , MEIJER ALBERT
Published: August 2005

We studied the effect of anodal capture at the ring electrode of the right ventricular (RV) lead on interventricular (V‐V) timing during biventricular (BiV) pacing, in which left ventricular (LV) pacing was preceding RV pacing. The V‐V interval was programmed from 80 to 4 ms (LV first) in the LV unipolar (LV tip—generator can) followed by the LV tip‐RV ring pacing configuration. In the LV unipolar configuration, V‐V programming leads to a continuous change in morphology of the QRS complex according to a change in collision of both activation fronts. When using the LV tip‐RV ring configuration with anodal capture at the RV ring electrode no change in QRS morphology was recorded varying the V‐V interval from 80 to 60 and 40 ms. However, at V‐V intervals between 20 and 4 ms a change in morphology of the QRS complex was recorded, which was due to additional cathodal stimulation of the RV tip electrode during RV stimulation.
Continuous Positive Airway Pressure Treatment Improves the QT Rate Dependence Adaptation of Obstructive Sleep Apnea Patients
Authors: ROCHE FRÉDÉRIC , BARTHÉLÉMY JEAN‐CLAUDE , GARET MARTIN , DUVERNEY DAVID , PICHOT VINCENT , SFORZA EMILIA
Published: August 2005

Background: QT rate dependence is one of the major properties of ventricular repolarization, with its circadian and autonomic modulations. The alteration of cardiac autonomic tone occurring in obstructive sleep apnea syndrome (OSAS) patients could explain the altered rate‐dependent adaptation of the myocardial repolarization. Thus, we postulated that dynamic alterations in QT interval adaptation could be ameliorated in OSAS patients under continuous positive airway pressure (CPAP) treatment. To assess ventricular repolarization features in patients with OSAS, we compared QT parameters and their dynamicities along RR intervals from 24‐hour ECG.

Methods: The study groups consisted of 38 consecutive OSAS patients and 38 healthy age‐matched subjects. The syndrome was confirmed for OSAS patients according to standard polysomnographic criteria (apnea plus hypopnea index: 56.9 ± 28.4/h). A second polysomnography synchronized with 24‐hour ECG Holter and realized under efficient CPAP therapy confirmed the control of sleep‐related breathing disorder.

Results: QT length related to heart rate was found significantly altered in patients with OSAS compared with controls (QTend/RR slope: −0.126 ± 0.031 vs −0.173 ± 0.038; P < 0.01). This flattened relationship was significantly improved with the treatment of the OSAS (−0.151 ± 0.051; P < 0.01 vs pretreatment status). There was no significant impact of CPAP therapy on ventricular ectopic activity as well as on static repolarization parameters (QT, RT, QTc, RTc) measured separately over daytime and nighttime.

Conclusions: The prognostic implications of such findings and the protective role of CPAP treatment to prevent sudden cardiac death in OSAS need to be evaluated.
Nested patterns of spatial diversity revealed for fish assemblages in a west European river
Authors: Ibarra A. A. , Park Y.‐S. , Brosse S. , Reyjol Y. , Lim P. , Lek S.
Published: August 2005

Abstract –  The longitudinal distribution of fish assemblages across a large west European river basin, the Garonne river (south‐west France) were investigated using a self‐organising map. This nonlinear statistical method was employed to classify sampling sites according to their species composition. We found three main nested patterns in an aggregated hierarchy: a replacement and succession of species along a gradient without defined boundaries, four main zones of fish assemblages and an upstream‐downstream shift of fish communities. We suggest that fish assemblages are too complex to be identified with a single species as in the zonation model, and that the diversity patterns found might be part of the same ecological process influencing fish assemblages on different spatial scales. Thus, discrepancies in the analysis of longitudinal patterns of fish communities in streams may have been basically a matter of local conditions and of conceptual perception.
Ancient and modern mitochondrial haplotypes of common bream (Abramis bramaL.) in Poland
Authors: Ciesielski S. , Makowiecki D.
Published: August 2005

Abstract – Genetic data on archaeological specimens provide complementary information for addressing questions on distribution and migration of fishes over long time scales. In this study DNA was extracted from common bream bones (N = 4), datedc.6000–1000 bp, and a 172 bp fragment of mitochondrialcytochrome bgene has been sequenced. The obtained sequences differed from homologous sequences of breams living contemporarily (N = 4), inhabiting the same geographical areas as ‘ancient’ fish. None of ancient mitochondrial haplotype was found in fish living at present. Our results suggest that fish vicariance could be affected also by other than glacial retreat historical events, and the mechanisms that influenced present distribution of freshwater fishes are still unclear.
Effects of exotic salmonids on juvenile Atlantic salmon behaviour
Authors: Scott R. J. , Poos M. S. , Noakes D. L. G. , Beamish F. W. H.
Published: August 2005

Abstract – We examined the effects of two salmonid species, chinook salmon (Oncorhynchus tschwaytscha) and brown trout (Salmo trutta), both exotic species to Lake Ontario, on behaviour and foraging success of juvenile Atlantic salmon (S. salar), a native species to Lake Ontario, in an artificial stream. We found that both exotic species have effects on Atlantic salmon behaviour, but that neither had an effect on foraging success. These results may explain why the Atlantic salmon re‐introduction programme in Lake Ontario has had little success, as more than 3 million exotic salmonids are released in Lake Ontario streams annually.
Use of ecological niche modelling to predict distributions of freshwater fish species in Kansas
Authors: McNyset K. M.
Published: August 2005

Abstract –  An essential innovation in aquatic biodiversity research would be a robust approach to accurately predict species’ potential distributions. In this paper, I conduct an analysis to test the efficacy of ecological niche modelling for predicting fish species’ potential distributions using an artificial‐intelligence algorithm, the Genetic Algorithm for Rule‐Set Prediction (GARP). Models of species’ ecological niches are developed using GARP, and projected onto geography to predict species distributions. To test the validity of this approach, I used freshwater fish distribution data for twelve fish species occurring in Kansas. These taxa were chosen to represent phylogenetic, distribution, and habit diversity. I subset these data by omitting half of the counties from model building, and test models using the omitted counties. Models were tested using Receiver Operating Characteristic (ROC) analyses. Of the species tested, all were statistically significant with the models showing excellent predictive ability. Omission errors across taxa ranged from 0 to 17%. This inferential capacity opens doors to many synthetic analyses based on primary point‐occurrence data.
Preoperative insertion of transanal ileus tubes for treatment of acute obstruction in cancer of the colon and rectum
Authors: OKI Eiji , OKUYAMA Toshiro , HIGASHI Hidefumi , YOSHIDA Michio , BABA Hideo , MAEHARA Yoshihiko
Published: August 2005

Background/Aims:  To evaluate the usefulness of treatment with a transanal ileus tube for acute obstruction in patients with cancer of colon and rectum.

Materials and methods:  In 12 patients with colorectal obstruction due to cancer treated between 1999 and 2001, lesions were located in the transverse colon, descending colon, sigmoid colon and rectum. Transanal ileus tube insertion was attempted for initial treatment and diagnosis.

Results:  Insertion of a transanal ileus tube was successful in eight (67%) of 12 patients. Symptoms of obstruction were resolved and one‐stage operations were performed in‐all eight cases. In two cases, insertion failed and temporary colostomy was used before a two‐stage operation. Perforation of the rectum and sigmoid colon occurred during the insertion procedure in another two cases. These two cases underwent emergency tumor resection and colostomy.

Conclusion:  Insertion of transanal ileus tube effectively relieved acute colonic obstruction. Furthermore, tube insertion allowed patients to undergo a one‐stage operation. However, tube insertion is not appropriate in all obstructive cases and the risk of severe complication must always be considered.
The impact of re‐excision on survival after unplanned resection in extremity soft tissue sarcomas
Authors: ATALAY Can , ÇETIN Bahadir , ZARALI Ozan , ALTINOK Mehmet
Published: August 2005

Background:  Patients with extremity soft tissue sarcomas are frequently treated with unplanned resections outside the specialized centers. Those patients treated with unplanned resections are evaluated for possible prognostic factors affecting disease‐free and overall survival.

Methods:  Patients were grouped after an unplanned resection as having: positive surgical margins; negative surgical  margins  treated  with  re‐excision;  or  no  further  surgery.  Patients’  age,  gender,  tumor  location, size, grade, group according to the surgical margin status and surgical treatment, adjuvant radio‐ and chemotherapy were evaluated as possible prognostic factors.

Results:  Seventy‐three patients were eligible for the study. Twenty‐seven patients (37%) had re‐excision due to positive surgical margins, 28 patients (38.3%) had surgery although the initial margins were negative and 18 patients (24.7%) with negative margins received no more surgery. The median disease‐free and overall survival were 35 and 52 months while 5‐year disease‐free and overall survival were 39% and 65%, respectively. In multivariate analysis, low tumor grade (P = 0.005) and adjuvant radiotherapy (P = 0.002) were the independent prognostic factors prolonging disease‐free survival and only the groups formed according to surgical margins and re‐excision had an independent effect on overall survival (OS) (P = 0.029).

Conclusion:  This study has indicated that a re‐excision in case of negative margins may decrease OS. In clinical practice, a re‐excision after unplanned resections should be performed in patients with positive margins.
Papanicolaou smear abnormalities in HIV‐infected women in north India
Authors: BAGGA Rashmi , WANCHU Ajay , RAJWANSHI Arvind , GUPTA KR , PRASAD GRV , GOPALAN Sarala , SACHDEVA RK
Published: August 2005

Background:  Dysplasia on Papanicolaou (Pap) smears have been reported in 15–40% of HIV‐positive women. These rates are 10–11 times higher than those observed among HIV‐negative women. Both the Center for Disease Control and Prevention and the Agency for Healthcare Policy and Research recommend that HIV‐infected women have a gynecologic evaluation including a Pap smear and pelvic examination as part of their initial evaluation.

Methods:  We performed pelvic examinations and took Pap smears in HIV‐positive women who attended the immunodeficiency clinic of the Postgraduate Institute of Medical Education and Research, Chandigarh, India, from August 2002 to September 2004. The cytology results were followed by colposcopy and/or biopsy if needed.

Results:  There were 136 women included in the study, and the age range was 21–58·years. Fourteen patients were menopausal, two had lactational amenorrhea, and five were pregnant. All were married and the majority (121 women) were parous. None of these women had any gynecologic symptoms. Speculum examination was clinically normal in 44 women, 24 had vaginal discharge suggestive of monilial vaginitis, 24 had vaginal discharge suggestive of a mixed infection and 44 had cervical erosion (with or without vaginitis). Bimanual pelvic examination was normal in nearly all, and only two had adnexal tenderness due to pelvic inflammatory disease. Pap smears were reported as normal in 65% of women and as inflammatory in 20%. Dysplasia was seen in 14 smears with invasive carcinoma in one. Seven women underwent colposcopic examination with directed biopsies where indicated. Despite initial counseling for a need for follow‐up, about one‐quarter of the women did not return to collect Pap smear reports and among this group were seven women with dysplasia.

Conclusion:  The high incidence of dysplasia in HIV‐positive women supports the recommendation of regular gynecologic examination including Pap smears in all these women even if they do not have any gynecologic symptoms. However, there is a need to have a better follow‐up so that appropriate therapeutic measures can be taken.
Usual diet before diagnosis and survival from colorectal cancer
Authors: HAYDON Andrew MM , MACINNIS Robert J , ENGLISH Dallas R , GILES Graham G
Published: August 2005

Background:  Much research has investigated possible links between diet and the risk of colorectal cancer, but little is known about whether dietary habits influence prognosis following diagnosis.

Methods:  Incident cases of colorectal cancer were ascertained among participants of the Melbourne Collaborative Cohort Study, a prospective cohort study of 41 528 Australians recruited between 1990 and 1994. Eligible participants had to be diagnosed with a first colorectal cancer between recruitment and 1 August 2002. At recruitment, participants answered a detailed food frequency questionnaire regarding their usual diet. Information on tumor site and stage, treatments given, recurrences and deaths was obtained from a systematic review of medical records.

Results:  Altogether, 526 cases of colorectal cancer were ascertained in the follow‐up period. Median follow up time among survivors was 5.5 years and 208 deaths had occurred, including 181 from colorectal cancer. The usual diet measured before diagnosis was not associated with either all‐cause, or colorectal cancer‐specific, mortality. No association was observed for diets high in meat, fruit, vegetables or fiber.

Conclusions:  Our study shows no association between usual diet measured sometime before diagnosis and survival from colorectal cancer.
Ray Based Model for the Ultrasonic Time-of-Flight Diffraction Simulation of Thin Walled Structure Inspection
Authors: Baskaran G. , Balasubramaniam K. , Krishnamurthy C. V. , Rao C. Lakshmana
Published: August 2005

It is necessary to size the cracklike defects accurately in order to extend the life of thin-walled (<10mm) components (such as pressure vessels) particularly for aerospace applications. This paper discusses the successful application of ray techniques to simulate the ultrasonic time-of-flight diffraction experiments for platelike structures. For the simulation, the diffraction coefficients are computed using the geometric diffraction theory. The A and B scans are simulated in near real time and the different experimental parameters can be interactively controlled due to the computational efficiency of the ray technique. The simulated results are applied to (1) defect signal identification for vertical defects, (2) inspection of inclined defects, and (3) study the effect of pulse width or probe frequency on experimental results. The simulated results are compared with laboratory scale experimental results.
Guided Wave Propagation Mechanics Across a Pipe Elbow
Authors: Hayashi Takahiro , Kawashima Koichiro , Sun Zongqi , Rose Joseph L.
Published: August 2005

Wave propagation across a pipe elbow region is complex. Subsequent reflected and transmitted waves are largely deformed due to mode conversions at the elbow. This prevents us to date from applying guided waves to the nondestructive evaluation of meandering pipeworks. Since theoretical development of guided wave propagation in a pipe is difficult, numerical modeling techniques are useful. We have introduced a semianalytical finite element method, a special modeling technique for guided wave propagation, because ordinary finite element methods require extremely long computational times and memory for such a long-range guided wave calculation. In this study, the semianalytical finite element method for curved pipes is developed. A curved cylindrical coordinate system is used for the curved pipe region, where a curved center axis of the pipe elbow region is an axis (z′ axis) of the coordinate system, instead of the straight axis (z axis) of the cylindrical coordinate system. Guided waves in the z′ direction are described as a superposition of orthogonal functions. The calculation region is divided only in the thickness and circumferential directions. Using this calculation technique, echoes from the back wall beyond up to four elbows are discussed.
Magnetostrictive Sensor for Generating and Detecting Plate Guided Waves
Authors: Kwun Hegeon , Kim Sang Young
Published: August 2005

The development of a magnetostrictive sensor for generating and detecting guided waves in ferromagnetic plate is described. The sensor consists of a channel-shaped core and coils wound around the core along its length. It is shown that the sensor is capable of generating and detecting both the symmetric and antisymmetric Lamb wave modes and the shear horizontal wave modes in plates. It is also found that the beam pattern produced by the sensor follows the pattern expected for a line source in a two-dimensional medium.
Gas Coupled Ultrasonic Measurement of Pipeline Wall Thickness
Authors: Shuttleworth Paul , Maupin Julie , Teitsma Albert
Published: August 2005

Magnetic Flux Leakage (MFL) is currently the standard method of gas pipeline inspection in spite of the fact that the accuracy of MFL is only about 10%. Ultrasonic inspection has much better accuracy and is not sensitive to permeability changes but normally requires a liquid couplant to get sufficient energy into the pipe wall. Reported here are the laboratory results of Gas Technology Institute’s (GTI) effort to investigate newly developed transducers that use gas as the coupling media. The combination of transducers specifically designed for this application and high gain amplifiers produced signals strong enough to measure wall thickness in steel at pressures from 200 to 1000 PSIG. Investigations showed that both the sensitivity of the transducers and the gas-metal coupling are functions of pressure and, therefore, limit the useful pressure range. Tests were run in pulse-echo mode and pitch-catch mode to determine the advantages and limitations of each. The average ultrasonic wall thickness will be used to calibrate the MFL improving the accuracy of its measurements.
Optimized Inspection of Thin-Walled Pipe Welds Using Advanced Ultrasonic Techniques
Authors: Lozev M. G. , Spencer R. L. , Hodgkinson D.
Published: August 2005

In this paper an effective way to optimize the inspection of welds in thin-walled pipe less than 6 mm (0.24 in.) thick using automated ultrasonic testing (AUT) is described. AUT offers a better solution than radiography for detecting and sizing of planar defects. However, cap width, weld shrinkage and defect sizing put constraints on the actual ultrasonic approach for inspection of pipes with wall thickness less than 6 mm (0.24 in.). The applications of high-frequency single/multiprobe techniques and phased-array technology for inspection of thin-walled pipe welds have been investigated in this paper. It has been demonstrated that combining an advanced ultrasonic phased-array technique with a novel approach for modeling and simulation of ultrasonic inspection have potentially significant advantages for enhanced detectability, better sizing and improved flaw characterization of randomly oriented planar fabrication imperfections in thin-walled pipe welds.
Small Diameter Remote Field Eddy Current Inspection for Unpiggable Pipelines
Authors: Teitsma Albert , Takach Stephen , Maupin Julie , Fox Jennifer , Shuttleworth Paul , Seger Paul
Published: August 2005

In-line inspection tools cannot inspect most of the natural gas transmission pipelines and distribution mains due to restrictions in the pipelines that will not allow a tool equipped with current inspection technologies to pass. Remote field eddy current (RFEC) inspection is an excellent candidate for inspecting a pipeline with multiple diameters, valve and bore restrictions and tight or miter bends. The results of this paper show that the RFEC technique can inspect pipeline materials, and that all of the components needed for RFEC inspection can be made much smaller that the pipe diameter. RFEC inspection is commercially available for inspecting small diameter piping without restrictions, several hundred feet at a time. The prototype design described in this paper shows this technology will work in a free-swimming tool that can inspect miles of pipeline at time and bypass restrictions.
In-Line Nondestructive Inspection of Mechanical Dents on Pipelines With Guided Shear Horizontal Wave Electromagnetic Acoustic Transducers
Authors: Zhao Xiaoliang , Varma Venugopal K. , Mei Gang , Ayhan Bulent , Kwan Chiman
Published: August 2005

Circumferential guided ultrasonic Shear Horizontal (SH) wave Electromagnetic Acoustic Transducer (EMAT) pairs mounted on a mobile fixture in a through-transmission mode were used for detection and characterization of mechanical dents on the outer surface of a pipe wall from inside the pipe. The dents were created on a 12 in. diameter standard seamless steel pipe by hydraulically pressing steel balls of various sizes into the pipe wall. n1 mode SH wave was directed through and along the wall of the pipe. Multiple measurements were obtained both from the dents and from the no-flaw region of the pipe using the EMAT pair. Dent features were extracted with a Principal Component Analysis (PCA) technique and classified into “cup” and “saucer” types using Discriminant Analysis (DA). The overall approach is able to detect and classify dents of depth 25% through wall or deeper, which should meet the needs of the pipeline safety inspection community (U.S. Department of Transportation, Research and Special Program Administration). Preliminary dent depth estimation potential is also shown via an amplitude correlation approach.
Use of cpSSRs for the characterisation of yam phylogeny in Benin
Authors: Chaïr H , Perrier X , Agbangla C , Marchand J L , Dainou O , Noyer J L
Published: August 2005

The Dioscorea cayenensis – Dioscorea rotundata species complex is the most widely cultivated yam in West Africa. This species complex has been described as deriving from wild yams belonging to the Enanthiophyllum section through domestication by African farmers. To study patterns of yam evolution and to establish phylogenetic relationships existing between wild and cultivated species sampled in Benin, we investigated changes in chloroplast DNA simple sequence repeats (cpSSR) in 148 yam accessions selected to cover the wider possible genetic diversity existing in the country. Dioscorea cayenensis and D. rotundata share the same haplotype. The morphotype "abyssinica" appeared to be subdivided into 2 haplotypes. One of these haplotypes shares the same haplotype with the Dioscorea cayenensis – Dioscorea rotundata species complex and with morphotypes praehensilis, suggesting that they might belong to the same species. Relationships among sections Lasiophyton, Macrocapaea, Opsophyton, and Enanthiophyllum were clarified, and some taxonomic changes within the Enanthiophyllum section were suggested. Dioscorea minutiflora, D. smilacifolia, and D. burkilliana might be considered as 1 single genetic group, and they are suspected of belonging to the same species.Key words: chloroplast genome, microsatellite, Dioscorea, Enanthiophyllum, taxonomy.
Assessment of the genetic diversity and phylogenetic relationships of a temperate bamboo collection by using transferred EST-SSR markers
Authors: Barkley N A , Newman M L , Wang M L , Hotchkiss M W , Pederson G A
Published: August 2005

Polymorphic expressed sequence tag - simple sequence repeat (EST-SSR) markers derived from major cereal crops were used to assess the genetic diversity of the USDA temperate bamboo collection consisting of 92 accessions classified in 11 separate genera and 44 species. A total of 211 bands were detected with a mean number of alleles per locus of 8.440. Phylogenetic relationships were determined by calculating genetic distances between all pairwise combinations and assessing differences in character data. The resulting dendrograms (unweighted pair group method with arithmetic means (UPGMA) and parsimony) clustered the accessions into 2 main clades, which corresponded to accessions characterized morphologically as either clumping (sympodial) or running (monopodial) bamboos. The majority of the accessions clustered according to their current taxonomic classification. These markers were also beneficial in identifying contaminated and (or) misidentified plots. Overall, these transferred markers were informative in differentiating the various bamboo accessions and determining the level of genetic variation within and among species and genera.Key words: bamboo germplasm, genetic diversity, phylogeny.
Integration of molecular and classical linkage groups of the silkworm,Bombyx mori(n = 28)
Authors: Yasukochi Yuji , Banno Yutaka , Yamamoto Kohji , Goldsmith Marian R , Fujii Hiroshi
Published: August 2005

Previously published linkage groups (LGs) composed of molecular markers were assigned to classical LGs in the silkworm, Bombyx mori (n = 28). Four markers from the classical linkage map, og, w-1, Lp, and Pfl, were assigned to the molecular linkage maps using sequence tagged sites. In addition, linkage analysis was carried out using BF1progeny between wild-type and mutant stocks carrying morphological phenotypic markers. As a result, the counterparts for 26 of 28 molecular LGs were identified with their counterparts of the classical LGs. Two visible markers, Sel and Xan, representing different classical LGs, were found to be linked.Key words: Bombyx mori, classical linkage group (LG), PCR-based genotyping, mutant, STS.
Ancient differentiation of the H and I haplomes in diploid Hordeum species based on 5S rDNA
Authors: Baum Bernard R , Johnson Douglas A , Bailey Grant L
Published: August 2005

5S rDNA clones from 12 South American diploid Hordeum species containing the HH genome and 3 Eurasian diploid Hordeum species containing the II genome, including the cultivated barley Hordeum vulgare, were sequenced and their sequence diversity was analyzed. The 374 sequenced clones were assigned to "unit classes", which were further assigned to haplomes. Each haplome contained 2 unit classes. The naming of the unit classes reflected the haplomes, viz. both the long H1 and short I1 unit classes were identified with II genome diploids, and both the long H2 and long Y2 unit classes were recognized in South American HH genome diploids. Based upon an alignment of all sequences or alignments of representative sequences, we tested several evolutionary models, and then subjected the parameters of the models to a series of maximum likelihood (ML) analyses and various tests, including the molecular clock, and to a Bayesian evolutionary inference analysis using Markov chain Monte Carlo (MCMC). The best fitting model of nucleotide substitution was the HKY+G (Hasegawa, Kishino, Yano 1985 model with the Gamma distribution rates of nucleotide substitutions). Results from both ML and MCMC imply that the long H1 and short I unit classes found in the II genome diploids diverged from each other at the same rate as the long H2 and long Y2 unit classes found in the HH genome diploids. The divergence among the unit classes, estimated to be circa 7 million years, suggests that the genus Hordeum may be a paleopolyploid.Key words: 5S DNA gene, molecular clock, paleopolyploid.
Construction of 2 intraspecific linkage maps and identification of resistance QTLs forPhytophthora capsiciroot-rot and foliar-blight diseases of pepper (CapsicumannuumL.)
Authors: Ogundiwin Ebenezer A , Berke Terry F , Massoudi Mark , Black Lowell L , Huestis Gordon , Choi Doil , Lee Sanghyeob , Prince James P
Published: August 2005

Two linkage maps of pepper were constructed and used to identify quantitative trait loci (QTLs) conferring resistance to Phytophthora capsici. Inoculations were done with 7 isolates: 3 from Taiwan, 3 from California, and 1 from New Mexico. The first map was constructed from a set of recombinant inbred lines (RILs) of the PSP-11 (susceptible) × PI201234 (resistant) cross; and the second map was from a set of F2lines of the Joe E. Parker' (susceptible) × 'Criollo de Morelos 334' (resistant) cross. The RIL map covered 1466.1 cM of the pepper genome, and it consisted of 144 markers - 91 amplified fragment length polymorphisms (AFLPs), 34 random amplified polymorphic DNA (RAPDs), 15 simple sequence repeats (SSRs), 1 sequence characterized amplified region (SCAR), and 3 morphological markers - distributed over 17 linkage groups. The morphological markers mapped on this population were erect fruit habit (up), elongated fruit shape (fse), and fasciculate fruit clusters (fa). The F2map consisted of 113 markers (51 AFLPs, 45 RAPDs, 14 SSRs, and 3 SCARs) distributed in 16 linkage groups, covering a total of 1089.2 cM of the pepper genome. Resistance to both root rot and foliar blight were evaluated in the RIL population using the 3 Taiwan isolates; the remaining isolates were used for the root-rot test only. Sixteen chromosomal regions of the RIL map contained single QTLs or clusters of resistance QTLs that had an effect on root rot and (or) foliar blight, revealing a complex set of genetics involved in resistance to P. capsici. Five QTLs were detected in the F2map that had an effect on resistance to root rot.Key words: Phytophthora capsici, QTLs, fasciculate, resistance, isolates, pepper, fruit shape.
Genetic analysis and high-resolution mapping of a premature senescence genePse(t)in rice (Oryza sativaL.)
Authors: Li Fuzhen , Hu Guocheng , Fu Yaping , Si Huamin , Bai Xuemei , Sun Zongxiu
Published: August 2005

A rice mutant, designated pse(t) (premature senescence, tentatively), was isolated from a T-DNA-inserted transgenic population. Senescence advanced more markedly in pse(t) than in wild-type ('Zhonghua 11', japonica) plants. Genetic analysis of pse(t) revealed that the premature senescence mutation was controlled by a single recessive nuclear gene, but that it was not induced by T-DNA insertion. In an effort to understand the genetic and molecular basis underlying premature senescence in rice, a map-based cloning strategy was used to localize Pse(t). High-resolution mapping of the Pse(t) locus was carried out using simple sequence repeat (SSR) and cleaved amplified polymorphic sequence (CAPS) markers. An F2population, comprising 1691 pse(t) individuals derived from a cross of the pse(t) mutant with 'Longtepu' (indica), was constructed. Several new polymorphism markers were developed in this study. Genetic linkage analysis showed that the Pse(t) gene was located on the long arm of chromosome 7. It was found that the Pse(t) gene cosegregated with 3 markers and was flanked by markers SS22 and PP21. Thus, the Pse(t) gene is located within a genetic distance of 0.15 cM, corresponding to a physical distance of 220 kb. These findings provide the basic information that can be used for the final isolation of this gene in the rice premature-senescence pathway.Key words: genetic analysis, high-resolution mapping, Oryza sativa L., premature senescence.
Linkage map of birch,Betula pendulaRoth, based on microsatellites and amplified fragment length polymorphisms
Authors: Pekkinen M , Varvio S , Kulju K K.M , Kärkkäinen H , Smolander S , Viherä-Aarnio A , Koski V , Sillanpää M J
Published: August 2005

The first genetic linkage map for silver birch, Betula pendula Roth, was constructed by using a pseudo-testcross mapping strategy and integration of linkage data from 3 unrelated 2-generation pedigrees. The map is based on the genetic inheritance and segregation of 82 amplified fragment length polyhmorphisms and 19 microsatellite markers, and was constructed by simultaneously comparing the performance of CRI-MAP and OUTMAP packages. The analysis revealed 16 linkage groups, and the total map coverage is 1561 cM (Kosambi units). Average map distance between adjacent markers is 15.5 cM. Linkage groups range between 6 and 18 loci and from 81.2 to 326.5 cM; the remaining 9 linkage groups consist of 2 or 3 loci ranging from 6.3 to 42.4 cM. The uncertainty of the map is illustrated with sensitivity analysis. This initial map can serve as a basis for developing a more detailed genetic map.Key words: Betula pendula, linkage map, microsatellite, AFLP, CRI-MAP, OUTMAP.
Unusual compact rDNA gene arrangements within some members of the Ascomycota: evidence for molecular co-evolution between ITS1 and ITS2
Authors: Hausner Georg , Wang Xi
Published: August 2005

The internal transcribed spacers of the ribosomal DNA tandem repeat were examined in members of the ascomycetous genus Sphaeronaemella. Species of Sphaeronaemella and its mitotic counterpart Gabarnaudia, have a compact rDNA gene arrangement due to unusually short internal transcribed spacer (ITS) regions. Examination of these regions from phylogenetically related taxa, Cornuvesica, Gondwanamyces, and Ceratocystis, showed that their ITS1 and ITS2 regions could be folded into central hairpin-like structures with the size reduction in species of Sphaeronaemella being due to length reduction of the main-hairpin and the loss of smaller hairpin-like structures that emanate from the main hairpin. A databank compilation, combined with newly obtained sequences, provided an ITS data set that includes sequences of 600 species belonging to the Ascomycota. Correlation analysis revealed that the sizes of ITS1 and ITS2 show a strong positive correlation, suggesting that the 2 rDNA regions have co-evolved. This supports biochemical evidence indicating that the ITS1 and ITS2 segments interact to facilitate the maturation of the rRNA precursor.Key words: rDNA, ITS1 and ITS2, Ascomycota, co-evolution.
A neural network model for predicting maximum shear capacity of concrete beams without transverse reinforcement
Authors: Seleemah Ayman Ahmed
Published: August 2005

Different relationships have been proposed by codes and researchers for predicting the shear capacity of members without transverse reinforcement. In this paper, the applicability of the artificial neural network (ANN) technique as an analytical alternative to existing methods for predicting this shear capacity is investigated using a critically reviewed and agreed upon database of experimental work that serves as a basis of comparison and (or) assessment of existing and new relationships. Both ANN and eight different codes and researcher's predictions of the shear capacity of the specimens of the database were compared. The ANN predictions are much superior to those of any of the current available relationships.Key words: artificial neural networks, shear capacity, transverse reinforcement, beams.
Bridge evaluation by mean load method per the Canadian Highway Bridge Design Code
Authors: Au Alexander , Lam Clifford , Agarwal Akhilesh C , Tharmabala Bala
Published: August 2005

The Canadian Highway Bridge Design Code (CHBDC) provides two alternative methods for evaluating the strength of existing bridges. The load and resistance factor method provides a general approach and covers the most extreme load situations that can occur in a general bridge population. The mean load method considers the uncertainties of loads acting on a specific bridge, the method of analysis, and resistance of the structure involved, and thus can provide a more accurate evaluation of individual bridges. Since traffic load represents a major portion of bridge loads, a better evaluation of specific bridges is obtained by using the statistical parameters of traffic loads observed on the structure. However, the overall accuracy depends heavily on capturing the most critical loading conditions during the survey periods. The mean load method is particularly valuable where actual traffic loads are expected to be significantly lower than those used in code calibration and when the potential economic benefits arising from a more realistic evaluation outweigh the extra costs of live load data collection and analysis. This paper demonstrates that the mean load method using site-specific traffic loading information can lead to a significantly higher live load-carrying capacity of a bridge.Key words: highway bridges, bridge evaluation, reliability, mean load method, bridge testing.
Determining ice-jam-surge characteristics from measured wave forms
Authors: Beltaos Spyros , Burrell Brian C
Published: August 2005

Upon the release of an ice jam, a wave or surge results that generates increased water stages and much higher flow velocities, posing various risks to local river ecology as well as to river structures and riverside communities. The temporal waveform can be easily measured, using water-level sensors, but the hydrodynamic characteristics of the surge, such as celerity, flow velocity, discharge, and shear stress, remain difficult to determine. An analytical method to deduce these parameters is developed herein, based on the equations of motion and plausible approximations for natural stream geometry. Preliminary comparisons with recent field measurements show promising results and demonstrate the degree to which a surge can magnify hydrodynamic forces. The methodology can be used in various applications, such as assessing the severity of a breakup event, estimating flow discharge during the passage of a wave, or evaluating scour potential in ecologically sensitive reaches and at river crossings.Key words: breakup, celerity, equations of motion, ice jam, shear stress, surge, velocity, wave.
Analytical formulation of maximum length limits of integral bridges on cohesive soils
Authors: Dicleli Murat , Albhaisi Suhail M
Published: August 2005

This paper presents an analytical approach for predicting the length limits of integral bridges built on cohesive soils based on the flexural strength of the abutments and the low cycle fatigue performance of the steel H-piles at the abutments under cyclic thermal loading. First, H-piles that can accommodate large inelastic deformations are determined considering their local buckling instability. Then, a damage model is used to determine the maximum cyclic deformations that such piles can sustain. Next, nonlinear static pushover analyses of typical integral bridges subjected to cyclic thermal variations are conducted to study the effect of various geometric, structural, and geotechnical parameters on their performance. Equations are derived by using the analyses results to determine the maximum length limits of integral bridges built on cohesive soils. It is found that the maximum length limits of integral bridges is affected by the stiffness of the deck, height of the abutment, properties, and orientation of the piles as well as stiffness of the cohesive soils.Key words: bridges, integral, steel, piles, fatigue, inelastic, thermal, clay, soil, length.
Water resources management in Beijing using economic input–output modeling
Authors: Wang Li , MacLean Heather L , Adams Barry J
Published: August 2005

To support more sustainable development of a region, decision support tools must consider local and global systems level impacts on the economy, environment, and society. Through the development and application of "economic input–output water resources" models for Beijing, China for the years 1985, 1990, and 1992, historical trends related to the economy structure and its water use are investigated. The study finds that the economy of Beijing and water use are highly concentrated in agriculture and heavy industry, but this intensive water use is indirectly reflected in the production of most other goods and services throughout the economy because of the interrelationships among various sectors of the economy. In spite of progress during the time period observed (e.g., between 1985 and 1990 the output of the economy doubled, but water consumption increased only 12% partly because of a significant increase in the price of water in 1988) and given the seriousness of water resources issues in the region, it is critical that future regional development make progress toward a more water-efficient economic system.Key words: water resources planning, urban water management, input–output modeling.
Euchromatic and heterochromatic domains at Drosophila telomeres
Authors: Biessmann Harald , Prasad Sudha , Walter Marika F , Mason James M
Published: August 2005

Noncoding repetitive sequences make up a large portion of eukaryotic genomes, but their function is not well understood. Large blocks of repetitive DNA-forming heterochromatin around the centromeres are required for this region to function properly, but are difficult to analyze. The smaller regions of heterochromatin at the telomeres provide an opportunity to study their DNA and protein composition. Drosophila telomere length is maintained through the targeted transposition of specific non-long terminal repeat retrotransposons to chromosome ends, where they form long tandem arrays. A subterminal telomere-associated sequence (TAS) lies immediately proximal to the terminal-retrotransposon array. Here, we review the experimental support for the heterochromatic features of Drosophila telomeres, and provide evidence that telomeric regions contain 2 distinct chromatin subdomains: TAS, which exhibits features that resemble beta heterochromatin; and the terminal array of retrotransposons, which appears euchromatic. This organization is significantly different from the telomeric organization of other eukaryotes, where the terminal telomerase-generated repeats are often folded in a t-loop structure and become part of the heterochromatin protein complex.Key words: Drosophila, telomere, gene silencing, position effect, heterochromatin.