bluuebunny/crossref_metadata_2025 huggingface dataset:
AN ADAPTIVE USER NAVIGATION MECHANISM AND ITS EVALUATION
Authors: BAEG JEONGWON , HIRAHARA ATSUSHI , FUKAZAWA YOSHIAKI
Published: November 2004

Recently, many on-line help systems have been developed that provide usage explanation for applications. However, it is difficult to find out necessary information in help contents and to understand how to obtain complete information. A navigation mechanism which can provide a user with essential information and guide the user so that he can carry out intended actions is indispensable. In this paper, we propose an adaptive navigation system which does not display navigation information on decisions that a user has already made by reflecting the current state of an application. In this research, in order to describe the structure of an application, Petri nets which are suitable for modeling event-driven systems are used. The application system is constructed based on these Petri nets. By communicating between the application system and its navigation system through these Petri nets, user navigation system reflecting the execution state of the application is realized.
OAP: AN OBJECT-ORIENTED APPROACH FOR PLANNING MODELING
Authors: ZALAKET JOSEPH , CAMILLERI GUY
Published: November 2004

This article describes a planning approach based on the object representation. A planning domain in OAP (Object-oriented Approach for Planning) consists of a dynamic set of objects. OAP provides a language for planning problems modeling and implementation. This approach can evolve a domain model from a literal (predicative) representation to an object based representation, as well as enhancing the development of planning problems. The goal of OAP is to offer the possibility to design and develop planning problems as any other software engineering problem, and to allow the application of planning to a larger class of domains by using methods (functions) that can be implemented within the world objects. Planning systems using OAP as language can be integrated into any existing object-oriented software with a slight additional effort to transform the system to a planning domain model, which allows the use of planning to solve generic tasks in existing software applications (Business, web,…). Therefore planning in real world systems will be easier to model and to implement using all the software engineering facilities offered by the object-oriented tools.
ENTREPRENEURIAL SPIRIT AMONG TERTIARY STUDENTS IN SINGAPORE
Authors: TAN WEE-LIANG , SIEW LAI-KUAN , TAN WEI-HONG , WONG SIOW-CHING
Published: November 2004

Much has been reported in the press [The Straits Times, "Emphasis On Examination Results May Curb Entrepreneurship, ENDEC Survey Report", 16 July 1993] about the lack of entrepreneurial spirit among young Singaporeans today. There appears to be a shortage of industrial, export-oriented and outward-looking entrepreneurs. It is noted that Singapore tertiary students are generally not interested or are not willing to be self-employed or to start their own business. Many prefer to be wage-earners in the public and private sectors. This is particularly true for university graduates who can command relatively high earnings and job security. Therefore they would prefer not to start out on their own which may entail higher risks. This study seeks to explore whether entrepreneurial spirit exists among Singapore tertiary students or there is really a dearth of budding entrepreneurs among the tertiary students. The objective therefore is to verify the extent of truth in the press reports. A prior study (Poon et al, 1993) was carried out but it was only limited to the students of the School of Accountancy and Business (SAB). The underlying motivation behind this present research is to assess the risk-seeking aptitude and innovative nature (creativity) prevalent among the tertiary students who represent the bulk of the young population and future leaders of Singapore. With the findings so gathered, suggestions and recommendations can then be put forward as to how to nurture or enhance the entrepreneurial spirit that is so vital to Singapore, at present and in the future.
CHINESE ENTREPRENEURS: STRATEGIC ADAPTATION IN A TRANSITIONAL ECONOMY
Authors: LOMBARDO GARY A.
Published: November 2004

A literature review is used as a basis to identify and present four key strategic issues addressed by entrepreneurs in modern Chinese enterprises: special economic zones, comprador concept, "rule of man" legal system, and social status. Survey questionnaire research is conducted and data analysis performed to assess responses by Chinese entrepreneurs concerning the strategic issues. The findings are reported.
FEMALE ENTREPRENEURS IN AUSTRALIA: AN INVESTIGATION OF FINANCIAL AND FAMILY ISSUES
Authors: BREEN JOHN , CALVERT CHERYL , OLIVER JUDY
Published: November 2004

This paper discusses the findings of a survey of female entrepreneurs in Australia and provides a profile of the female entrepreneur and their business activity. The characteristics of the entrepreneur are described, including their motivation for going into business, their attitudes toward training and joining networks. The issues of access to finance and family/business conflict are further investigated in the light of current literature. The results indicate that female entrepreneurs in Australia are well educated and tend to commence their businesses with low start-up capital obtained from personal savings or from family and friends. Their businesses are concentrated in the services sector, with a significant number starting out as home-based businesses. Despite evidence that female entrepreneurs have difficulty in obtaining loan funds, the survey results indicated that a high proportion of female entrepreneurs applying for loans were successful. Further analysis of the survey data indicated that the reason for the loan success had little to do with the strength of the business. This was evidenced by the respondents advising that the main type of information requested at the loan interview was personal financial details, that a high proportion of loans were secured by the family home, and that financial institutions required little in the way of ongoing reporting.
"ENTREPRENEURIAL SURVIVAL SKILLS IN THE MIDST OF ECONOMIC CHAOS" AN ANALYSIS OF SMALL BUSINESSES PRIOR TO THE GENERAL ELECTION OF 1992 IN GUYANA
Authors: RAGHUNANDA M.
Published: November 2004

It is generally agreed that small businesses tangibly contribute to both the stability and health of the national economy. They employ more than 25% of the workforce, produce on an on-going basis a tidy revenue for the state and create more than 50% of the new jobs. The pioneers behind these businesses are the entrepreneurs who understand the organizations' purpose and can best devise methods to exploit the windows of opportunities.

This paper reviews several pieces of literature on small businesses in Guyana in order to provide an understanding of the entrepreneurial survival strategies employed to keep the businesses open. Studies show that entrepreneurial behaviour, management skills and competence were key ingredients in the successful operation of small businesses in Guyana. The results indicate that twenty four entrepreneurial routes were successfully followed to float small businesses prior to the Guyanese 1992 general election. The paper concludes by making some pronouncements on the future of small businesses in Guyana and supports the drive for the state to empower the entrepreneurs and the people for development.
THE USE OF FMEA IN PROCESS QUALITY IMPROVEMENT
Authors: JANAKIRAM MANI , KEATS J. BERT
Published: November 2004

Failure Mode and Effects Analysis (FMEA) is well-known as a useful tool in the design process. It is used by some engineers as part of process characterization studies. Yet FMEA is virtually ignored in most process quality improvement paradigms. We suggest its use in quality improvement programs and indicate where it belongs and how it can be applied.
THREE TESTING PROCEDURES FOR A COMPETING RISKS MODEL
Authors: FONG DANIEL Y.T. , YIP PAUL
Published: November 2004

This paper is concerned with testing for the equality of failure rates in a competing risks model with two risks. Three testing procedures are investigated, namely Score test, Likelihood Ratio test and Wald test. Wald test has been considered to be the most powerful in multivariate linear regression analysis.1 However in our application, Wald test is the most efficient one when the failure rate of the second failure type is strictly smaller than the first failure type, otherwise the Score or the Likelihood Ratio test is preferred. This phenomenon is illustrated by data from a mechanical-switch life test.2 The results has been extended to a k-competing risks model. A simulation study is also given to examine the performance of the three tests.
AVAILABILITY AND RELIABILITY MODELING OF AN INTEGRATED UNDERGROUND COAL MINING SYSTEM
Authors: DUAN CHUNMING , TOPUZ ERTUGRUL
Published: November 2004

This paper presents a systematic approach to evaluation of the availability of an automated underground coal mining system, the longwall system. Five analytical models are developed by applying the techniques of reliability modeling and stochastic systems analysis. Each model is formulated to evaluate the availability of a longwall system with unique longwall operating logic. The application of these models is illustrated with a case study and the uses of the results are discussed.
AN EXPERIMENTAL COMPARISON OF SAFETY-SPECIFIC VERSUS NON-SAFETY-SPECIFIC SOFTWARE METHODS
Authors: GOWEN LON D. , YAP MAY YEE , COLLOFELLO JAMES S.
Published: November 2004

Due to the rapid increase in computer-related technologies, various organizations are continuing to put higher demands on software systems. These demands are sometimes placing software in total or partial control over critical system functions such as navigating planes, controlling traffic systems, identifying military targets, and facilitating medical treatments to name just a few. Unfortunately, certain faults in such a system can result in catastrophic consequences such as death, injury, or environmental harm. To help ensure that software systems are safe, developers use safety-specific techniques in addition to more general non-safety-specific techniques. However, no experimental studies exist that compare safety-specific versus non-safety-specific techniques. Such experiments are necessary in order to determine whether or not developers using safety-specific software techniques are able to produce software systems with statistically fewer latent hazardous faults than those developers not using these techniques. Furthermore, such experiments are necessary in order to determine weaknesses in current methods, thus pinpointing areas for future research. In order to provide an initial data point in this area, the authors conducted an experiment that compared certain safety-specific and non-safety-techniques at developing a small safety-critical software system. This paper discusses this experiment, presents its results, and statistically analyzes the results.
PERFORMABILITY AND COST ANALYSIS OF DEGRADABLE SYSTEMS
Authors: NORDMANN LARS , PHAM HOANG
Published: November 2004

Many models and methods have been proposed in the literature to evaluate the reliability of fault-tolerant systems. In this paper, we study systems with one degradation mode. We introduce a static model and present efficient algorithms for the evaluation of the system performance and cost. For the special case of a system consisting of identical units we derive an efficient procedure for the determination of an optimal system design with respect to a minimum system cost.
ANALYSIS OF COLD-STANDBY SYSTEMS — CUTTING AND CLUSTERING THE STATE SPACE
Authors: GOPALAN M.N. , KUMAR U. DINESH
Published: November 2004

In this paper two methods, namely cutting and clustering the state space are discussed to find approximate solutions to n-unit cold-standby system with a single repair facility. It has been assumed that the failure rate is constant and the repair time is arbitrarily distributed. A mathematical model is developed using semi-regenerative phenomena and systems of convolution integral equations satisfied by various state probabilities corresponding to different initial conditions are obtained. Explicit expressions for the availability and the reliability of the system are obtained. An iterative method is used to solve the systems of integral equations obtained and a comparative study has been carried out between exact and approximate solutions.
A SUPERSTRUCTURE OF CAPABILITY INDICES — ASYMPTOTICS AND ITS IMPLICATIONS
Authors: VÄNNMAN KERSTIN , KOTZ SAMUEL
Published: November 2004

A family of capability indices, containing the indices Cp, Cpk, Cpm, and Cpmk, has earlier been defined by Vännman for the case of two-sided specification intervals. By varying the parameters of the family various indices with suitable properties can be obtained. Under the assumption of normality the asymptotic expected value and mean square error are derived. The obtained asymptotic expressions provide a convenient tool for determining specific values of the parameters, which satisfy the suggested suitable criteria for the estimators. Numerical investigations are carried out and recommendations for the values of the parameters are provided based on these calculations.
PERFORMABILITY EVALUATION OF FAULT-TOLERANT COMPUTER SYSTEMS USING DYQNTOOL+
Authors: HAVERKORT BOUDEWIJN R.
Published: November 2004

For fault-tolerant computer systems (FTCS) supporting critical applications, it is of key importance to be able to answer the question of whether they indeed fulfill the quality of service requirements of their users. In particular, answers related to the combined performance and dependability of the FTCS are important. To facilitate these so-called performability studies, we present DYQNTOOL+, a performability evaluation tool based on the dynamic queuing network concept, that allows for a combined modeling of system performance and dependability. Different from other performability evaluation tools, DYQNTOOL+ combines two different modeling paradigms, i.e., queuing networks and stochastic Petri nets, for respectively the performance and the dependability aspects of the system under study. The mutual relations between these two model parts, such as workload-induced failures and performance decreases due to failures, are explicitly modeled as well. By the above choice for such a combination of modeling paradigms, the modeling can be done in greater detail, thereby often revealing system behavior that cannot be revealed otherwise. We present the dynamic queuing network modeling approach and its implementation in DYQNTOOL+, as well as illustrate its usage by addressing a number of examples.
RELIABILITY ANALYSIS OF PHASED MISSIONS
Authors: SCHNEEWEISS WINFRID G.
Published: November 2004

It is shown that in a number of cases mission success probabilities and related reliability measures can be determined, once appropriate mission phases are defined. The results are general, i.e., not limited to the Markov model case, but intentionally kept “simple” by considering only few components and few different phases. The problems specifically addressed (and solved) are: (1) Non-ideal switches for activating spares, (2) and (3) degraded operation, and change from TMR (Triple Modular Redundancy) to simplex structure on the first component failure, respectively, (4) preventive renewals after alternating periods, and (5) load-dependent two-phased life time distribution.
INFLUENCE OF SURFACE MODIFICATION ON THE ADSORPTION DYNAMICS OF O2 ON Cu{100}
Authors: JUNELL P. , AHONEN M. , HIRSIMÄKI M. , VALDEN M.
Published: November 2004

Translational energy ( E T ) dependence of oxygen ( O 2) adsorption on clean and modified Cu {100} has been studied by molecular beam surface scattering (MBSS) experiments. The role of surface defects on the adsorption dynamics has been investigated by blocking the defects with Ag and oxygen atoms, and by increasing the defect density with Ar +-ion bombardment. At low E T the adsorption of O 2 is shown to be indirect and facilitated either by a dynamical steering mechanism or a precursor state. At high E T the defects have only marginal effect on the adsorption. Additionally, the modification of the surface electronic structure by preadsorbed oxygen is shown to have a pronounced effect on the adsorption dynamics, whereas the electronic structure modification by preadsorbed Ag is shown to be relatively inefficient in changing the reactivity of Cu {100} towards O 2 adsorption.
CHARACTERIZATION OFAl+SECONDARY ION EMISSION PRODUCED BYNe+ANDAr+BOMBARDMENT OF ALUMINIUM SURFACE
Authors: TOLSTOGOUZOV A. , BELYKH S. F. , STEPANOVA M. , DEW S. K. , PAGURA C.
Published: November 2004

This paper reports the characterization of the velocity (energy) dependencies of the Al+secondary ion emission produced by 0.5 keV and 5 keV Ne+and Ar+bombardment of polycrystalline pure aluminium. The distributions of secondary Al+ions over their kinetic energy were measured for emission energies of 1–1000 eV without applying electric fields to force the ions into the mass–energy analyzer. To extract the ionization probability, the measured energy distributions of emitted ions were normalized with respect to reference energy distributions of neutral atoms. The reference distributions were obtained by original numerical simulations, as well as analytically, through a sophisticated normalization of the Thompson distribution. It was shown that for both extraction methods, the logarithmic plots of the normalized secondary ion fraction versus the normal component of the reciprocal ion velocity (the reciprocal or inverse velocity plots) are nonmonotonic, with two peaks and two linear portions situated at a low emission energy (Ek=5–25 eV ) and at a high emission energy (Ek=80–280 eV ). The linear portions were fit by exponential dependency P+∝ exp (-v0/vn) with two different values of the characteristic velocity v0. For the low emission energy, the value v01~(3.3±0.2)×106cm / s was independent of the mass and energy of the projectiles. However, for the high emission energy, the characteristic velocity depended on the projectile's mass, M, namely v02~(5.3±0.3)×106cm / s for Ne+and v02~(8.1±0.3)×106cm / s for Ar+; the ratio v02( Ne+)/v02( Ar+) is close to the value [Formula: see text]. This indicates that ballistic mechanisms might contribute to affect the high-energy part of the reciprocal velocity plots along with nonballistic ionization processes, which are generally believed to be the only significant factor for the plots.
MAGNETIC FIELD AND INTENSE LASER RADIATION EFFECTS ON THE INTERBAND TRANSITIONS IN QUANTUM WELL WIRES
Authors: KASAPOGLU E. , SARI H. , GÜNEŞ M. , SÖKMEN I.
Published: November 2004

Magnetic field and intense laser radiation effects on the exciton binding energy and interband optical transitions in quantum well wires is calculated using a variational method and in the effective mass approximation. The results obtained show that the exciton binding energies and op interband absorption depend on the sizes of the quantum well wire, intense laser field and magnetic field. The additional confinement of the particles in the quantum well wire offers greater variety of the intense laser field and magnetic field dependence in comparison to three- and two-dimensional materials.
CREEP ACTIVATION ENERGY OF FLOW PROCESS IN Sn0.2Bi1.8Te3 SINGLE CRYSTALS
Authors: SONI P. H. , DESAI C. F. , BHAVSAR S. R.
Published: November 2004

Temperature dependence of the Vickers microhardness of Sn 0.2 Bi 1.8 Te 3 single crystals has been studied. Loading time dependence of microhardness at different temperatures has been used for creep study in the temperature range 303 K–373 K. The activation energy for indentation creep of the crystals has been evaluated.
A STUDY ON THE EFFECT OF ANNEALING PROCESS ON SOUND VELOCITY AND INTERNAL FRICTION USING THE VIBRATING REED TECHNIQUE
Authors: MUKHOPADHYAY P. K. , KUMAR UDAY , BADAWI EMAD
Published: November 2004

Al has unique intrinsic characteristics, which are of interest to scientists as well as engineers. Al and its alloys are slightly paramagnetic materials. Al has very low cross section for thermal neutrons of 0.23 barn, hence Al can be used in nuclear fields as a structural material which is virtually transparent to neutrons. We report VRT as a new technique to study material problems. We also discuss, the results of sound velocity and internal friction, and resonance frequency as a function of temperature range for a pure aluminum sample under investigation. By using VRT, we found that the annealing temperature (450°C) is sufficient to remove the type of defects introduced in the materials under study. The activation energy to remove point defect for Al samples was calculated and found to be about 0.0624 eV. Also, we could easily observe that Q-1 is a function of annealing time. From these measurements of sound velocity and internal friction we can conclude that VRT is a powerful tool for detecting and probing the physical properties of the material under study. Internal friction is a microscopic property for the indication of the purity of the sample. Sound velocity depends on the state of the materials (which depends on the process of treatment).
SURFACE ELECTRON RESONANCES IN VLEED
Authors: BARTOŠ I. , READ M. N.
Published: November 2004

The important role of surface resonances in determining the intensities of electron beams diffracted from the Cu (111) surface is shown and interpreted in model calculations with a step-barrier of variable thickness in front of the crystal surface. The importance of using a finely tuned surface barrier potential in VLEED intensity calculations is stressed.
Effects of pre-, peri-, and postmyocardial infarction treatment with losartan in rats: effect of dose on survival, ventricular arrhythmias, function, and remodeling
Authors: Pourdjabbar Ali , Parker Thomas G. , Nguyen Quang Trinh , Desjardins Jean-Francois , Lapointe Nathalie , Tsoporis James N. , Rouleau Jean-Lucien
Published: November 2004

Angiotensin receptor blockers (ARBs) reduce adverse left ventricular (LV) remodeling and improve LV function and survival when started postmyocardial infarction (MI). ARBs also reduce ventricular arrhythmias during ischemia-reperfusion injury when started pre-MI. No information exists regarding their efficacy and safety when started pre-MI and continued peri- and post-MI. We evaluated whether the ARB losartan improves the outcome when started pre-MI and continued peri- and post-MI. Male Wistar rats ( n = 502) were treated for 7 days pre-MI with losartan at a high dose (30 mg·kg−1·day−1), progressively increasing dose (3 mg·kg−1·day−1 increased to 10 mg·kg−1·day−1 10 days and 30 mg·kg−1·day−1 20 days post-MI), or no treatment. Ambulatory systolic blood pressure and Holter monitoring were performed for 24 h post-MI. Echocardiography was done 30 days post-MI, and LV remodeling, cardiac hemodynamics, and fetal gene expression were assessed 38 days post-MI. High-dose losartan reduced 24-h post-MI survival compared with the progressive dose and control (21.9% vs. 36.6% and 38.1%, P = 0.033 and P = 0.009, respectively). This was associated with greater hypotension in the high dose and no change in ventricular arrhythmias in all groups. In 24-h post-MI survivors, the progressive dose group had reduced mortality from 24 h to 38 days (8.5% vs. 28.6% for control vs. 38.9% for high dose, P = 0.032 and P = 0.01, respectively). Survivors of both losartan groups demonstrated improved LV remodeling, cardiac hemodynamics, preserved GLUT-4, and reduced cardiac fetal gene expression. Pretreatment with ARBs does not reduce 24-h post-MI ventricular arrhythmias or survival, and high doses increase mortality by causing excessive hypotension. In 24-h post-MI survivors, progressively increasing doses of losartan have multiple beneficial effects, including improved survival.
L-type Ca2+channel function in the avian embryonic heart after cardiac neural crest ablation
Authors: Nichols Carol A. , Creazzo Tony L.
Published: November 2004

In avian and mammalian embryos, surgical ablation or severely reduced migration of the cardiac neural crest leads to a failure of outflow tract septation known as persistent truncus arteriosus (PTA) and leads to embryo lethality due partly to impaired excitation-contraction coupling stemming primarily from a reduction in the L-type Ca2+current ( ICa,L). Decreased ICa,Loccurs without a corresponding reduction in the α1-subunit of the Ca2+channel. We hypothesize that decreased ICa,Lis due to reduced function at the single channel level. The cell-attached patch clamp with Na+as the charge carrier was used to examine single Ca2+channel activity in myocytes from normal hearts from sham-operated embryos and from hearts diagnosed with PTA at embryonic days (ED) 11 and 15 after laser ablation of the cardiac neural crest. In normal hearts, the number of single channel events per 200-ms depolarization and the mean open channel probability ( Po) was 1.89 ± 0.17 and 0.067 ± 0.008 for ED11 and 1.14 ± 0.17 and 0.044 ± 0.005 for ED15, respectively. These values represent a normal reduction in channel function and ICa,Lobserved with development. However, the number of single channel events was significantly reduced in hearts with PTA at both ED11 and ED15 (71% and 47%, respectively) with a corresponding reduction in Po(75% and 43%). The open time frequency histograms were best fitted by single exponentials with similar decay constants (τ ≅ 4.5 ms) except for the sham operated at ED15 (τ = 3.4 ms). These results indicate that the cardiac neural crest influences the development of myocardial Ca2+channels.
Fibrinogen and fragment D-induced vascular constriction
Authors: Lominadze David , Tsakadze Nina , Sen Utpal , Falcone Jeff C. , D'Souza Stanley E.
Published: November 2004

Elevated fibrinogen (Fg) concentration in blood is a high risk factor for many cardiovascular diseases. We hypothesize that Fg and its early degradation product, fragment D, may result in arterial constriction by binding endothelial intercellular adhesion molecule-1 (ICAM-1). The vasoconstriction induced by Fg and fragment D was studied in third- and second-order arterioles (3As and 2As, respectively) of Sprague-Dawley rat cremaster muscle in vivo, in aortic and femoral artery rings, and in the segments of first-order arterioles (1As) isolated from rat cremaster muscle. Intravascular infusion of Fg induced significant constriction of 3As and 2As (by 33.4 ± 3.4 and 23.7 ± 4.3%, respectively) in vivo and was abolished in the presence of the specific endothelin type A receptor blocker BQ-610. Fg and fragment D produced significant constriction of both aortic and femoral artery rings. Isolated 1As constricted in response to Fg (0.3 μM) and fragment D (3 μM) by 31 ± 1.4 and 12 ± 1.5%, respectively. Fluorescently labeled Fg and fragment D bound to the vascular wall, whereas albumin bound to a significantly lesser degree. The binding of Fg and fragment D to the arteriolar wall and constriction of aortic and femoral artery rings as well as isolated 1As were abolished in the presence of anti-Fg and anti-ICAM-1 antibodies. These results indicate that binding of Fg and fragment D to the vascular wall through ICAM-1 may contribute to the increased vascular tone and resistance that compromise circulation.
Uterine motor alterations and estrous cycle disturbances associated with colonic inflammation in the rat
Authors: Houdeau Eric , Larauche Muriel , Monnerie Régine , Bueno Lionel , Fioramonti Jean
Published: November 2004

The impact of colitis on uterine contractility and estrous cycle was investigated after intracolonic administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats. Colitis severity was assessed by macroscopic damage scoring (MDS) 4 days after TNBS, and myeloperoxidase (MPO) activity was measured in both colon and uterus of control and colitic rats. Estrous cycle stages were determined by vaginal smears and histology, and uterine contractility was assessed in vitro on longitudinal and circular strips. In control rats, uterine MPO activity varied markedly during the cycle and peaked around estrus. In rats with moderate colitis [MDS < 5, 3.1 ± 0.2 (mean ± SE)], uterine MPO decreased by 61% compared with estrus control, without disruption of the cycle. Frequency of spontaneous contractions was reduced by 32% in circular muscle. Contractile responses to KCl and carbachol were not affected, whereas maximal response to oxytocin decreased by 47% in the longitudinal muscle. In rats with severe colitis (MDS > 5, 6.0 ± 0.2), uterine MPO was reduced by 96% and estrous cycle was disrupted. Spontaneous contractility was impaired in circular strips, and a 39% decrease in the contraction frequency occurred in the longitudinal strips. Circular strips did not contract to KCl or carbachol; however, longitudinal strips had maximal responses to KCl, carbachol, and oxytocin reduced by 36%, 27%, and 46%, respectively. Estrogen replacement protected the uterine responses to carbachol in colitic rats, whereas oxytocin responses remained depressed. These data indicate that colonic inflammation can influence both spontaneous and evoked uterine contractility, in relation to estrous cycle disturbances, impaired estradiol production, and functional alterations of myometrial cells.
Community-Based Program for the Diagnosis and Prevention of Genetic Disorders in Cuba
Authors: Heredero-Baute Luis
Published: November 2004

The author’s experience of 20 years as director of the medical genetic services program in Cuba is presented. The setting of the infrastructure for equipment and the training of personnel for the medical genetic program began in 1981 in the city of Havana, and was progressively extended to cover the whole country in 1988. Between 1982 and 2002, 2.8 million pregnant women were tested for sickle cell carrier status, 96,000 carriers and 4,786 couples at risk were detected and offered genetic counseling and prenatal diagnosis. In the same period, the combination of maternal serum α-fetoprotein screening and fetal ultrasound led to the prenatal diagnosis of anomalies in several thousand fetuses. The accessibility to legal abortion, and the autonomous decisions by the majority of couples to terminate abnormal pregnancies reduced the prevalence of neural tube defects and sickle cell disease at birth by 90 and 65%, respectively, by 2002. In the span of approximately 20 years, 22,690 pregnant women at risk received prenatal chromosomal diagnosis. Newborn screening for phenylketonuria and congenital hypothyroidism was established. Genetic counseling was offered to every detected person or family at risk for genetic conditions. The network of medical genetic services established in the country received a very positive acceptance by the population. A very successful connection with the primary health care level was established.
Medical Genetics in Peru
Authors: Quiroga de Michelena Maria Isabel
Published: November 2004

Peru has a growing population characterized by notorious socioeconomic differences. The main health problems are acquired diseases related to sanitary conditions that affect mainly the large segment afflicted by poverty and extreme poverty. The state’s health policy does not contemplate any action on congenital or genetic conditions, and genetic services are considered a very low priority. In spite of this, some of the best medical schools have undergraduate and graduate programs in genetics, and there is a growing group of specialists that makes its best to impulse the practice of medical genetics in Peru. Many ethical and legal dilemmas, common to other countries in the region, and derived from social inequality, and political, cultural and religious factors, are also faced in everyday practice.
Medical Genetics in Zulia, a State of Venezuela
Authors: González-Ferrer Sandra , Pineda-Bernal Lennie , Delgado-Luengo Wilmer , Villalobos-Cabrera Heber
Published: November 2004

Zulia is a state located in the northwest of Venezuela. Congenital malformations, deformities and chromosomal anomalies are the second cause of infant and neonatal mortality. There are seven public and private groups providing genetic services, the most important of which, the Medical Genetic Unit at the Zulia University was created in 1973. So far, this unit has provided genetic services to 12,000 families, and has been responsible for undergraduate and postgraduate education in human and medical genetics. Prenatal diagnosis is performed at the Unit and a private practice group, the most frequent referral reason being advanced maternal age. The most frequent genetic diseases in the state are Huntington’s disease, sickle cell anemia, neural tube defects and Down’s syndrome. Research in genetics includes the clinical, epidemiological and molecular characterization of hereditary diseases, cancer, reproductive problems and genetic diversity. Other public groups are conducting research on dementias, including Alzheimer’s disease, and on the genotoxic effects of environmental pollutants.
Comparison of WHO 1973, WHO/ISUP 1998, WHO 1999 Grade and Combined Scoring Systems in Evaluation of Bladder Carcinoma
Authors: Bircan Sema , Candir Ozden , Serel T. Ahmet
Published: November 2004

Objectives: To compare WHO 1973, WHO/ISUP 1998 and WHO 1999 histologic grading systems, and also to evaluate the primary (most common) and secondary (second most common) patterns of cancer growth according to these three grading systems. Material and Methods: The study consisted of 87 bladder transurethral resections that were classified as grade 1, 2 and 3, and papillary urothelial neoplasm of low malignant potential (PUNLMP), low grade (LG) and high grade (HG) carcinoma considering WHO 1973 and WHO/ISUP, respectively. The WHO 1999 system was subdivided high grade into grades 2 and 3 (HG-2 and HG-3). For combined scoring, primary (most common) and secondary (second most common) grades according to extension were recorded for three grading systems. The number was repeated when only grade was seen in all extension of the tissue examined. A final combined score was obtained which ranged from 2 to 6 for the WHO 1973 and WHO/ISUP 1998 systems and from 2 to 8 for the WHO 1999 schema. The TNM system was used for the pathologic staging. Results: When considering the pathological stage, there were statistical differences between the WHO 1973 grades (p = 0.011 and p = 0.000), and LG and HG carcinomas of WHO/ISUP 1998 (p = 0.000) and also the WHO 1999 grades (p = 0.010 and p = 0.003), except PUNLMP. Regarding the combined scoring, significant differences were found between score 4 (2 + 2) and 5 (2 + 3) of WHO 1973 (p = 0.014) and score 5 (LG + HG) and 6 (HG + HG) of WHO/ISUP 1998 (p = 0.011). There was also a significant difference between scores 4 and 6, and 6 and 8 of the WHO 1999 combined scoring system (p = 0.019 and p = 0.019). WHO 1973, WHO/ISUP 1998 and WHO 1999 systems were positively correlated with the pathological stage (rs = 0.30, rs = 0.52 and rs = 0.50, respectively), whereas there was weak association between the combined scoring systems and stage (rs = 0.20, rs = 0.18 and rs = 0.19). Comparing these grading systems, the grade 2 of WHO 1973 was subdivided into LG and HG in WHO/ISUP 1998 and also LG-1and HG-2 in WHO 1999 systems. The group of HG carcinoma in WHO/ISUP 1998 which was subdivided into HG-2 and HG-3 in the WHO 1999 system was different statistically in relation to the stage. Conclusions: Our results revealed that the WHO 1999 system may be more useful to evaluate the bladder carcinoma histopathologically in comparison to the WHO 1973 and WHO/ISUP 1998 systems.
Comparative Study of Apoptotic Antitumor Effect between Angiogenesis Inhibitor AGM-1470 and MVAC Chemotherapy on Rat Urinary Bladder Cancer
Authors: Sejima Takehiro , Isoyama Tadahiro , Miyagawa Ikuo
Published: November 2004

Objectives: To investigate the antitumor apoptotic effect of AGM-1470 by comparing it to that induced by methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) therapy, currently the standard chemotherapy for bladder cancer, in a rat bladder cancer model. Materials and Methods: A total of 45 six-week-old female rats were divided into 3 equal groups: those receiving AGM-1470 treatment; those receiving MVAC treatment, and controls. All rats were cystectomized to evaluate the therapeutic effect with regard to macroscopic tumor findings, hematoxylin and eosin pathology, apoptosis detection, and immunohistochemistry (IHC) for bcl-2. Results: Our experimental protocol succeeded in producing invasive bladder tumors in the majority of rats. Tumor volume was significantly reduced in the AGM-1470 and MVAC treatment groups compared with that in the control group. The apoptotic indices of tumor cells was significantly higher in the AGM-1470 and MVAC treatment groups than in the control group. IHC for bcl-2 demonstrated no statistical difference in expression among the groups. However, the apoptotic indices of high-level bcl-2 expression were significantly lower than the indices of low-level expression in the AGM-1470 group. Conclusions: AGM-1470 and MVAC appear to exert a prominent mass reduction effect via tumor cell apoptosis in cases of invasive bladder tumor, although these therapies did not demonstrate any obvious modulation of bcl-2 protein expression status. Bcl-2 overexpression might be an obstacle to AGM-1470 therapy because of its significant inhibitory effect on apoptosis.
Retroperitoneoscopic Ureterolithotomy for the Treatment of Ureteral Calculi
Authors: Demirci Deniz , Gülmez İbrahim , Ekmekçioğlu Oğuz , Karacagil Mustafa
Published: November 2004

Introduction: Most upper or middle ureteral stones are treated with shock wave lithotripsy or endoscopic techniques. In rare cases the ureteral stones are treated with open surgery after failure of first-line treatments. Retroperitoneoscopy is a minimally invasive alternative to open surgery. Patients and Methods: Between May 1995 and January 2001, twenty-one patients underwent retroperitoneoscopic ureterolithotomy. The stones in upper and middle ureter were large and impacted (5 patients) or not fragmented after shock wave lithotripsy (16 patients). A balloon dissector was placed and infiltrated with 800 ml air in the retroperitoneal space. Three 10-mm trocars were used. The pressure was kept at 15 mm Hg by carbon dioxide insufflation. The stones were extracted from the ureter using a laparoscopic stylet. Results: The stones in 17 patients were successfully removed in a median operating time of 105 (min–max 45–190) min. Urine extravasation in all cases and pnomoscrotum in 2 cases were observed as postoperative complications. The median hospital stay was 6 (min–max 3–22) days with minimal analgesic requirement. Conclusion: Retroperitoneoscopic ureterolithotomy is a useful and effective alternative treatment technique to open surgery when first-line treatments have failed or are unlikely to be effective.
Bladder Neck Stenosis after Transurethral Resection of Prostate: Does Size Matter?
Authors: Al-Singary W. , Arya M. , Patel H.R.H.
Published: November 2004

Aim: To understand the risk factors associated with the incidence of bladder neck stenosis (BNS) after transurethral prostate surgery. Patients and Methods: We retrospectively reviewed 900 patients who underwent transurethral prostate surgery over a 4-year period. The mean age of the men was 72.3 (47–94) years. The specific outcome data assessed related to BNS, including type of operation performed, resected tissue weight and history of previous surgery in the lower urinary tract. Results: 29 (3.4%) patients developed BNS at a mean of 10.3 (3–33) months, with a mean resected prostatic tissue weight of 11 ± 3.7 g. Four of the 29 patients with BNS were treated with bladder neck resection and re-stenosed. Fifty-four men underwent bladder neck incision for small prostates with a high bladder neck, measured by digital rectal examination and assessed cystoscopically, with no BNS. All the remaining patients from our series did not have a BNS, with a mean resected weight of 28 ± 8.9 g, which is statistically greater than in the BNS group (p < 0.05, unpaired t test). Conclusions: BNS after transurethral prostate surgery is a significant problem. It is clear from our study that resection in small prostates with no sign of a high bladder neck will increase the development of BNS. Thus, small prostates should be managed by an initial bladder neck incision, even if the bladder neck is not high.
Paraganglioma of the Bladder: Controversy regarding Treatment
Authors: Pastor-Guzmán José María , López-García Samuel , Giménez-Bachs José Miguel , Ruíz-Mondejar Rafael , Cañamares-Pabolaza Luis , Atiénzar-Tobarra Manuel , Casado-Moragón Luis , Virseda-Rodriguez Julio A.
Published: November 2004

Paragangliomas or extra-adrenal pheochromocytomas account for approximately 15% of all pheochromocytomas. They are usually found in an intradiaphragmatic location. Paragangliomas of the urinary bladder are infrequent and represent 6% of the paragangliomas and 0.06% of all bladder tumors. We describe 2 cases of urinary bladder paragangliomas attended to our center and review the literature with special attention to treatment, since there is some controversy around the management of these tumors. Surgical options include partial or total cystectomy and transurethral resection, but there is no consensus regarding these treatment modalities. The 2 patients presented underwent transurethral resection with a good outcome and no recurrence or residual disease.
Development of Leiomyosarcoma from Primary Leiomyoma?
Authors: Loertzer H. , Krause U. , Holzhausen H.J. , Hamza A. , Fornara P.
Published: November 2004

Kidney leiomyosarcoma represents a rare variety of malignant kidney tumours. In this paper, we report on a patient with an inoperable leiomyosarcoma. Since this neoplasm is very rare, there is very little information on this type of malignancy. We present the symptoms, radiological findings, diagnostic criteria and differential diagnosis of the tumour. Leiomyosarcoma exhibits aggressive biological behaviour and has a poor prognosis. We have found that the treatment of choice is a radical nephrectomy.
Phosphatidylinositol 3-Kinase Offsets cAMP-Mediated Positive Inotropic Effect via Inhibiting Ca
2+
Influx in Cardiomyocytes
Authors: Leblais Veronique , Jo Su-Hyun , Chakir Khalid , Maltsev Victor , Zheng Ming , Crow Michael T. , Wang Wang , Lakatta Edward G. , Xiao Rui-Ping
Published: November 2004

Phosphoinositide 3-kinase (PI3K) has been implicated in β
2
-adrenergic receptor (β
2
-AR)/G
i
-mediated compartmentation of the concurrent G
s
-cAMP signaling, negating β
2
-AR–induced phospholamban phosphorylation and the positive inotropic and lusitropic responses in cardiomyocytes. However, it is unclear whether PI3K crosstalks with the β
1
-AR signal transduction, and even more generally, with the cAMP/PKA pathway. In this study, we show that selective β
1
-AR stimulation markedly increases PI3K activity in adult rat cardiomyocytes. Inhibition of PI3K by LY294002 significantly enhances β
1
-AR–induced increases in L-type Ca
2+
currents, intracellular Ca
2+
transients, and myocyte contractility, without altering the receptor-mediated phosphorylation of phospholamban. The LY294002 potentiating effects are completely prevented by βARK-ct, a peptide inhibitor of β-adrenergic receptor kinase-1 (βARK1) as well as G
βγ
signaling, but not by disrupting G
i
function with pertussis toxin. Moreover, forskolin, an adenylyl cyclase activator, also elevates PI3K activity and inhibition of PI3K enhances forskolin-induced contractile response in a βARK-ct sensitive manner. In contrast, PI3K inhibition affects neither the basal contractility nor high extracellular Ca
2+
-induced increase in myocyte contraction. These results suggest that β
1
-AR stimulation activates PI3K via a PKA-dependent mechanism, and that G
βγ
and the subsequent activation of βARK1 are critically involved in the PKA-induced PI3K signaling which, in turn, negates cAMP-induced positive inotropic effect via inhibiting sarcolemmal Ca
2+
influx and the subsequent increase in intracellular Ca
2+
transients, without altering the receptor-mediated phospholamban phosphorylation, in intact cardiomyocytes.
An Improved Time Interpolation for Three-Dimensional Doppler Wind Analysis
Authors: Liu Shun , Qiu Chongjian , Xu Qin , Zhang Pengfei
Published: November 2004

A temporal interpolation is required for three-dimensional Doppler wind analysis when the precise measurement time is counted for each radar beam position. The time interpolation is traditionally done by a linear scheme either in the measurement space or in the analysis space. Because a volume scan often takes 5–10 min, the linear time interpolation is not accurate enough to capture the rapidly changing winds associated with a fast-moving and fast-growing storm. Performing the linear interpolation in a frame moving with the storm can reduce the error, but the analyzed wind field is traditionally assumed to be stationary in the moving frame. The stationary assumption simplifies the computation but ignores the time variation of the true wind field in the moving frame. By incorporating a linear time interpolation into the moving frame wind analysis, an improved scheme is developed. The merits of the new scheme are demonstrated by idealized examples and numerical experiments with simulated radar observations. The new scheme is also applied to real radar data for a supercell storm.
Sensitivity of Perturbation Variance and Fluxes in Turbulent Jets to Changes in the Mean Jet
Authors: Farrell Brian F. , Ioannou Petros J.
Published: November 2004

Synoptic-scale eddy variance and fluxes of heat and momentum in midlatitude jets are sensitive to small changes in mean jet velocity, dissipation, and static stability. In this work the change in the jet producing the greatest increase in variance or flux is determined. Remarkably, a single jet structure change completely characterizes the sensitivity of a chosen quadratic statistical quantity to modification of the mean jet in the sense that an arbitrary change in the jet influences a chosen statistical quantity in proportion to the projection of the change on this single optimal structure. The method used extends previous work in which storm track statistics were obtained using a stochastic model of jet turbulence.
The Connection between Coherent Structures and Low-Frequency Wave Packets in Large-Scale Atmospheric Flow
Authors: Hodyss Daniel , Nathan Terrence R.
Published: November 2004

A theory is presented that addresses the connection between low-frequency wave packets (LFWPs) and the formation and decay of coherent structures (CSs) in large-scale atmospheric flow. Using a weakly nonlinear evolution equation as well as the nonlinear barotropic vorticity equation, the coalescence of LFWPs into CSs is shown to require packet configurations for which there is a convergent group velocity field. These LFWP configurations, which are consistent with observations, have shorter wave groups with faster group velocities upstream of longer wave groups with slower group velocities. These wave group configurations are explained by carrying out a kinematic analysis of wave focusing, whereby a collection of wave groups focus at some point in space and time to form a large amplitude wave packet having a single wave front. The wave focusing and the subsequent formation of CSs are enhanced by zonal variations in the background flow, while nonlinearity extends the lifetimes of the CSs. These results are discussed in light of observed blocking formation in the Atlantic–European and South Pacific regions.