bluuebunny/crossref_metadata_2025 huggingface dataset:
Gestational trophoblastic disease: is intensive follow up essential in all women?
Authors: Pisal Narendra , Tidy John , Hancock Barry
Published: November 2004

Objective  To determine the timescale of the registration process for gestational trophoblastic disease and its impact on hCG level at registration and subsequent need for chemotherapy.

Design  A prospective observational study using a standardised protocol for registration, assessment and treatment for molar pregnancy.

Setting  A supra‐regional tertiary referral centre for gestational trophoblastic disease.

Participants  A total of 2046 consecutive women registered between January 1994 and December 1998 with a diagnosis of molar pregnancy.

Methods  Data at and after registration, collected prospectively on a computerised database, were statistically analysed (by multiple logistic regression and ANOVA).

Main outcome measures  Relationship between length of time to and hCG value at registration; also the subsequent need for chemotherapy.

Results  A total of 2046 women with a diagnosis of molar pregnancy were registered in the study period. The mean time interval between first evacuation and registration at the referral centre was 47 days (median 37, range 0–594). One hundred and five out of 2046 (5.1%) women needed chemotherapy. Sixty‐three precent of the women (1296 out of 2046) had a normal level of urinary hCG (less than 40 IU/24 hours) at the time of registration and only one (0.08%) needed chemotherapy. Binary logistic regression analysis showed a statistically significant relationship between time to registration, hCG value, histology, pretreatment risk score and decision to administer chemotherapy.

Conclusion  Women with gestational trophoblastic disease who were registered late were significantly more likely to have normal levels of hCG and were less likely to need chemotherapy. A less intensive follow up may be justified in women with gestational trophoblastic disease who are registered with a normal hCG level.
Prevalence, nature, severity and correlates of postpartum depressive symptoms in Vietnam
Authors: Fisher J.R.W , Morrow M.M. , Nhu Ngoc N.T. , Hoang Anh L.T.
Published: November 2004

Objective  To examine depressive symptomatology in women after childbirth in Ho Chi Minh City, Vietnam.

Design  A cross sectional survey.

Setting  Hung Vuong Obstetrics and Gynaecology Hospital and the Maternal, Child Health and Family Planning Center of Ho Chi Minh City, Vietnam.

Population  Mothers of infants aged ±six weeks attending well‐baby clinics.

Method  Participants were recruited consecutively in the postnatal wards and invited to take part in the study at the first clinic visit. Individual structured interviews about health and social circumstances, including the Edinburgh Postnatal Depression Scale (EPDS) were administered during clinic visits. The interview schedule was translated into Vietnamese, back translated for verification and piloted. Interviewers were specifically trained members of staff of the two centres.

Main outcome measures  EPDS scores and responses to structured questions about specific and non‐specific symptoms.

Results  Of 506 women who participated, 166 (33%) had EPDS scores in the clinical range of >12 and 99 (19%) acknowledged suicidal ideation. In a forward stepwise logistic regression analysis, 77% of cases with EPDS scores >12 were correctly classified in a model which included unwelcome pregnancy, lack of a permanent job, <30 days complete rest after childbirth, an unsettled baby, not being given special foods, avoiding proscribed foods and being unable to confide in their husbands.

Conclusion  Depressive symptomatology is more prevalent among parturient women in Ho Chi Minh City, Vietnam than reported rates in developed countries and is at present unrecognised.
Mitochondrial hTERT exacerbates free‐radical‐mediated mtDNA damage
Authors: Santos Janine Hertzog , Meyer Joel N. , Skorvaga Milan , Annab Lois A. , Van Houten Bennett
Published: November 2004

Telomerase is often re‐activated in human cancers and is widely used to immortalize cells in culture. In addition to the maintenance of telomeres, telomerase has been implicated in cell proliferation, genomic instability and apoptosis. Here we show that human telomerase reverse transcriptase (hTERT) is targeted to the mitochondria by an N‐terminal leader sequence, and that mitochondrial extracts contain telomerase activity. In seven different human cell lines, mitochondrial telomerase increases hydrogen‐peroxide‐mediated mitochondrial DNA damage. hTERT expression did not alter the rate of hydrogen peroxide breakdown or endogenous cellular levels. Because the damaging effects of hydrogen peroxide are mediated by divalent metal ions (Fenton chemistry), we examined the levels of bioavailable metals. In all cases, higher levels of chelatable metals were found in hTERT‐expressing cells. These results suggest that mitochondrial telomerase sensitizes cells to oxidative stress, which can lead to apoptotic cell death, and imply a novel function of telomerase in mitochondrial DNA transactions.
Cellular lifespan and senescence signaling in embryonic stem cells
Authors: Miura Takumi , Mattson Mark P. , Rao Mahendra S.
Published: November 2004

Most mammalian cells when placed in culture will undergo a limited number of cell divisions before entering an unresponsive non‐proliferating state termed senescence. However, several pathways that are activated singly or in concert can allow cells to bypass senescence at least for limited periods. These include the telomerase pathway required to maintain telomere ends, the p53 and Rb pathways required to direct senescence in response to DNA damage, telomere shortening and mitogenic signals, and the insulin‐like growth factor – Akt pathway that may regulate lifespan and cell proliferation. In this review, we summarize recent findings related to these pathways in embryonic stem (ES) cells and suggest that ES cells are immortal because these pathways are tightly regulated.
Alterations in the TGFβ signaling pathway in myogenic progenitors with age
Authors: Beggs Marjorie L. , Nagarajan Radhakrishnan , Taylor‐Jones Jane M. , Nolen Greg , MacNicol Melanie , Peterson Charlotte A.
Published: November 2004

Myogenic progenitors in adult muscle are necessary for the repair, maintenance and hypertrophy of post‐mitotic muscle fibers. With age, fat deposition and fibrosis contribute to the decline in the integrity and functional capacity of muscles. In a previous study we reported increased accumulation of lipid in myogenic progenitors obtained from aged mice, accompanied by an up‐regulation of genes involved in adipogenic differentiation. The present study was designed to extend our understanding of how aging affects the fate and gene expression profile of myogenic progenitors. Affymetrix murine U74 Genechip analysis was performed using RNA extracted from myogenic progenitors isolated from adult (8‐month‐old) and aged (24‐month‐old) DBA/2JNIA mice. The cells from the aged animals exhibited major alterations in the expression level of many genes directly or indirectly involved with the TGFβ signaling pathway. Our data indicate that with age, myogenic progenitors acquire the paradoxical phenotype of being both TGFβ activated based on overexpression of TGFβ‐inducible genes, but resistant to the differentiation‐inhibiting effects of exogenous TGFβ. The overexpression of TGFβ‐regulated genes, such as connective tissue growth factor, may play a role in increasing fibrosis in aging muscle.
Mechanical properties across hypomineralized/hypoplastic enamel of first permanent molar teeth
Authors: Mahoney Erin , Ismail F. Shaira M. , Kilpatrick Nicky , Swain Michael
Published: November 2004

The aims of the present study were to investigate the mechanical properties of first permanent molars affected with enamel hypomineralization or hypoplasia, and to describe the appearance of these lesions under scanning electron microscopy. Eight first permanent molar test teeth and two unaffected premolars (controls) were enclosed in resin, then sectioned axially and polished. The hardness and modulus of elasticity was determined from a single array of indentations made parallel to the amelo–dentinal junction using an Ultra‐Micro‐Indentation system. The teeth were then examined using the scanning electron microscope. The mechanical properties of the test teeth in the unaffected cervical region (hardness and modulus range, 2.03–4.99 GPa and 50.39–96.87 GPa, respectively) were similar to those of the control enamel (hardness and modulus range, 2.71–4.15 GPa and 62.06–95.77 GPa, respectively). Between the unaffected cervical enamel and the hypomineralized region there was a transitional area of 500–600 µm where the mechanical properties in the experimental teeth decreased linearly. The mechanical properties of the hypomineralized region of each experimental tooth were significantly lower than those of the control or cervical regions (hardness and modulus range, 0.07–1.74 GPa and 3.26–40.96 GPa, respectively). The scanning electron microscopy views revealed disorganized enamel with poorly demarcated prism boundaries in the affected regions. In conclusion, the hardness and modulus of elasticity of hypomineralized enamel in first permanent molars is significantly less than in unaffected areas of the same tooth. The reason for this is unclear but may be related to the lack of organization of the enamel crystals.
Influence of pH and time on organic substance release from a model dental composite: a fluorescence spectrophotometry and gas chromatography/mass spectrometry analysis
Authors: Örtengren Ulf , Langer Sarka , Göransson Anna , Lundgren Ted
Published: November 2004

In this study we assessed the influence of pH and time on the degradation and elution of organic substances from the composite resin material, Z‐100. To accomplish this, fluorescence spectrophotometry was evaluated as an appropriate technique for the identification of six organic substances (methacrylic acid, methyl methacrylate, hydroquinone, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate and 4,4′‐isopropylidenediphenol) that were eluted from resin composite material stored for 24 h or 6 months at pH 4.0, 6.0 or 8.0. In addition, complementary analyses (solid‐phase microextraction/gas chromatography/mass spectrometry) were carried out to identify and quantify the substances. The main substances leached from the resin composite were methacrylic acid, triethylene glycol dimethacrylate and hydroquinone. It was concluded that fluorescence spectrophotometry seems to be a suitable, non‐destructive technique for the qualitative analysis of eluted organic components. Critical combinations of time and pH allowed the elution of several organic substances, predominantly methacrylic acid, triethylene glycol dimethacrylate and hydroquinone, from the model resin composite, Z‐100.
Single species biofilm‐forming ability of root canal isolates on gutta‐percha points
Authors: Takemura Naoki , Noiri Yuichiro , Ehara Atsushi , Kawahara Takashi , Noguchi Nobuo , Ebisu Shigeyuki
Published: November 2004

The participation of bacterial biofilms in the over‐filled gutta‐percha points associated with refractory periapical periodontitis has recently been reported. This study investigated the initial biofilm‐forming ability of root canal isolates (Enterococcus faecalis, Streptococcus sanguis, Strep. intermedius, Strep. pyogenes, Staphylococcus aureus, Fusobacterium nucleatum, Propionibacterium acnes, Porphyromonas gingivalis and Prevotella intermedia) on gutta‐percha points in vitro. Each bacterial strain was suspended in 100% cell culture medium or in culture medium containing 4.5, 45 or 90% (vol/vol) serum. The bacterial suspensions were then co‐incubated anaerobically with gutta‐percha points for 7 d. The gutta‐percha points were processed for scanning electron microscopic observation and examined for biofilm presence and thickness. E. faecalis, Strep. sanguis, Strep. intermedius, Strep. pyogenes and Staph. aureus biofilms were generated on the surfaces of the specimens incubated in culture medium supplemented with 45 or 90% (vol/vol) serum. The E. faecalis and Strep. sanguis biofilms were significantly thicker than those of Strep. intermedius, Strep. pyogenes and Staph. aureus. No biofilms were detected on the specimens incubated with F. nucleatum, Prop. acnes, Porph. gingivalis and Prev. intermedia. These findings suggest that Gram‐positive facultative anaerobes have the ability to colonize and form extracellular matrices on gutta‐percha points, while serum plays a crucial role in biofilm formation.
Electron microscopic detection of salivary α‐amylase in the pellicle formed in situ
Authors: Deimling Daniela , Breschi Lorenzo , Hoth‐Hannig Wiebke , Ruggeri Alessandra , Hannig Christian , Nekrashevych Yuriy , Prati Carlo , Hannig Matthias
Published: November 2004

Immunological and biochemical analyses have shown that α‐amylase is an essential component of the acquired pellicle. After adsorption, this enzyme might act as a receptor for bacterial adherence. However, data indicating that amylase is bound to the pellicle surface in vivo and thus available for adhering bacteria are rare. Therefore, the present study focused on α‐amylase within the pellicle formed in situ, using gold‐immunolabeling electron microscopic techniques. Pellicles were formed by intra‐oral exposure of enamel specimens for 30 and 120 min in six subjects. The results obtained by transmission electron microscopy indicate that amylase was randomly distributed in the pellicle layer without any preferential localization within the pellicle. Thus, salivary α‐amylase might be considered as an important structural component that is even involved in the early stages of pellicle formation. The findings of field emission in‐lens scanning electron microscopy provided evidence that the enzyme is located on the pellicle surface. It could be concluded that α‐amylase might act as a receptor for bacterial adherence to the pellicle in vivo.
Inability to relate tooth forms to face shape and gender
Authors: Wolfart Stefan , Menzel Holger , Kern Matthias
Published: November 2004

This study aimed to examine whether there exists a gender‐dependent correlation between the inverted face shape and that of the upper central incisor as the literature often suggests. Standardized portraits and anterior tooth photographs of 204 dental students were made. Standardized enlargements of facial outlines and of the upper right incisor outlines were traced. They were classified into three different shapes: tapered, ovoid and square‐shaped. Ten dentists determined twice – with an intervening interval of 3 wk – the gender of the students on the basis of the anterior tooth photographs. Tooth and face shapes could be classified as tapered (25% and 27%, respectively), ovoid (39% and 41%, respectively) or square‐shaped (36% and 32%, respectively). A significant correlation could be shown between face shape and gender, but not between tooth shape and gender. The dentists were correct about the gender of the subjects in 47 to 59% of all cases. The reproducibility of their judgments varied between 54% and 77%. The theory that the tooth shape should correspond to the inverted facial shape could therefore not be confirmed. In addition it could be shown that the participants were not capable of determining a subject's gender from intraoral photographs alone.
Real‐time dimensional change in light‐cured composites at various depths using laser speckle contrast analysis
Authors: Sato Tomomi , Miyazaki Masashi , Rikuta Akitomo
Published: November 2004

Laser speckle contrast analysis is an interferometric technique that is used to measure the displacement of the rough surface of a specimen. The purpose of this study was to present a laser speckle correlation method for monitoring real‐time dimensional changes of light‐cured composites. Uncured composite was condensed into a glass tube and irradiated for 30 s with 600 or 200 mW cm−2. The speckle patterns obtained from lateral and bottom composite surfaces were monitored using a speckle analyser. The speckle field is recorded in a digital frame and stored by image processing system as the carrier of information on the displacement of the tested surface. The calculated values were obtained for each pair of adjacent patterns and the changes in speckle contrast as a function time were obtained from five repeated measurements. The overall magnitude of the speckle contrasts decreased soon after the initial light exposure and gradually increased thereafter. The speckle contrasts obtained from the bottom surface were smaller than those obtained from the lateral surface. This tendency was more pronounced when the specimen was irradiated with lower power density. It can be concluded that monitoring differential shrinkage at various levels of depth can be achieved with this new technique.
The Living Tomorrow Project: how Philip Morris has used a Belgian tourist attraction to promote ventilation approaches to the control of second hand smoke
Authors: Pilkington P , Gilmore A B
Published: November 2004

Study objective:To examine the involvement of Philip Morris in Living Tomorrow 2 and determine the rationale behind its involvement.

Design:Research was conducted through a web based search of internal tobacco industry documents made publicly available through litigation.

Main results:For approximately €1 000 000 Philip Morris (now Altria) became a co-initiator of Living Tomorrow 2, a tourist complex in Belgium that aims to demonstrate how we will be living in the future. In addition to promoting the company and its grocery products, Philip Morris is using the complex and its website to promote ventilation as a means of accommodating smokers and non-smokers in the indoor environment. Particular emphasis was placed on the bar and restaurant areas. Despite the rationale for its involvement, Philip Morris fails to acknowledge its role as a cigarette manufacturer. As a form of corporate sponsorship Philip Morris thought its involvement could evade any European tobacco advertising ban.

Conclusions:Philip Morris is using a tourist attraction to promote its views on control of second hand smoke (SHS) and accommodation of smokers and non-smokers in the indoor environment. However, ventilation does not deal with the health effects of SHS. Policymakers must be cognisant of the devious tactics the industry employs to promote its own agenda, especially in relation to indoor air quality and smoking in public places. Tobacco control legislation should be continually modified and strengthened in response to the changing activities of the tobacco industry as it strives to evade existing legislation and deter the advent of new legislation.
“Asia is now the priority target for the world anti-tobacco movement”: attempts by the tobacco industry to undermine the Asian anti-smoking movement
Authors: Knight J , Chapman S
Published: November 2004

Study objective:To identify and examine the strategies utilised by multinational tobacco companies to undermine and discredit key anti-tobacco activists and organisations in the Asian region.

Method:A series of case studies drawing upon material gathered through systematic reviews of internal tobacco industry documents.

Date sources:Tobacco industry documents made public as part of the settlement of the Minnesota Tobacco Trial and the Master Settlement Agreement.

Results:The industry sought to identify, monitor, and isolate key individuals and organisations. The way industry went about fulfilling this mandate in the Asian region is discussed. Industry targetted individuals and agencies along with the region’s primary anti-smoking coalition.

Conclusions:Attack by multinational tobacco companies is a virtual quid pro quo for any individual or agency seriously challenging industry practices and policies. Understanding their tactics allows anticipatory strategies to be developed to minimise the effectiveness of these attacks.
Advocacy in action: extreme corporate makeoverinterruptus: denormalising tobacco industry corporate schmoozing: Figure 1
Authors: Chapman S
Published: November 2004

The tobacco industry continues to seek corporate “respectability”, despite being responsible for the deaths of millions of smokers worldwide every year
PRINCIPAL TYPE ASSIGNMENT TO LAMBDA TERMS
Authors: HIROKAWA SACHIO
Published: November 2004

A principal type-scheme of a λ-term is a most general type-scheme for the term. This paper presents two characterizations of principal type assignment figures. By the first characterization, a decision procedure is shown for the principality of a type assignment figure. By the second characterization, an algorithm is presented which transforms a type assignment to a λ-term into a principal type assignment to the term in O(k4m4) steps where k is the size of the given type and m is the size of the given term. This gives a new proof for the principal type-scheme theorem which states: if a λ-term has a type then it has a principal type. The proof in this paper is simpler than known proofs which use the unification.
THE STRUCTURE AND COMPLEXITY OF MINIMAL NFA’S OVER A UNARY ALPHABET
Authors: JIANG TAO , McDOWELL EDWARD , RAVIKUMAR B.
Published: November 2004

Many difficult open problems in theoretical computer science center around non-determinism. We study the fundamental problem of converting a given deterministic finite automaton (DFA) to a minimal nondeterministic finite automaton (NFA). Despite extensive work on finite automata, this fundamental problem has remained open. Recently, we studied this problem and showed that this (and related) problems are computationally hard.11 Herewe study the restriction of this problem to the case when the input DFA is over a one-letter alphabet. Even in this restricted case the problem is computationally hard even though our evidence of hardness is different from (and is weaker than) the standard ones such as NP-hardness. Let A → B denote the problem of converting a finite automaton of type A to a minimal finite automaton of type B. Our main result is that DFA → NFA , when the input is a unary cyclic DFA (a DFA whose graph is a simple cycle), is in NP but not in P unless NP ⊆ DTIME (nO( log n)). Our work was also motivated by the problem of finding structurally simple “normal forms” of NFA’s over a unary alphabet. We present some normal forms for minimal NFA’s over a unary alphabet and present an application to lower bounds on the size complexity of an NFA. In fact, the normal form result is used in a nontrivial manner to show the NP membership result stated above.
GRAMMARS BASED ON PATTERNS
Authors: DASSOW JÜRGEN , PAUN GHEORGHE , SALOMAA ARTO
Published: November 2004

Some new generative devices are defined, called pattern grammars, starting from the way of identifying a language by a pattern in [2,5] (they can be viewed also as a generalization of Marcus contextual grammars [6]). The generative capacity of these grammars is investigated (compared mainly with L-language families), as well as closure, decision and descriptional complexity questions.
ON TWO APPROXIMATION ALGORITHMS FOR THE CLIQUE PROBLEM
Authors: STEWART IAIN A.
Published: November 2004

We look at well-known polynomial-time approximation algorithms for the optimization problem MAX-CLIQUE (“find the size of the largest clique in a graph”) with regard to how easy it is to compute the actual cliques yielded by these approximation algorithms. We show that even for two “pretty useless” deterministic polynomial-time approximation algorithms, it is unlikely that the resulting clique can be computed efficiently in parallel. We also show that for each non-deterministic algorithm, it is unlikely that there is some deterministic polynomial-time algorithm that decides whether any given vertex appears in some clique yielded by that nondeterministic algorithm.
ON THE EQUIVALENCE OF TWO-WAY PUSHDOWN AUTOMATA AND COUNTER MACHINES OVER BOUNDED LANGUAGES
Authors: IBARRA OSCAR H. , JIANG TAO , TRAN NICHOLAS , WANG HUI
Published: November 2004

It is known that two-way pushdown automata are more powerful than two-way counter machines. The result is also true for the case when the pushdown store and counter are reversal-bounded. In contrast, we show that two-way reversal-bounded push-down automata over bounded languages (i.e., subsets of [Formula: see text] for some distinct symbols a1,…, ak) are equivalent to two-way reversal-bounded counter machines. We also show that, unlike the unbounded input case, two-way reversal-bounded pushdown automata over bounded languages have decidable emptiness, equivalence and containment problems.
APPLICATION OF LEARNING THEORY TO AN ARTIFICIAL NEURAL NETWORK THAT DETECTS INCIPIENT FAULTS IN SINGLE-PHASE INDUCTION MOTORS
Authors: Chow Mo-yuen , Bilbro Griff , Yee Sui Oi
Published: November 2004

The generalization ability of a neural network in a specific application is of interest to many neural network designers. In this paper, learning theory is applied to a neural network used for incipient fault detection in single-phase induction motors. This paper will show that learning theory can help determine the proper number of training examples needed to reach a specific performance level, so that excessive and unnecessary training examples can be avoided. Comparisons of the results of learning theory and Monte Carlo estimate are presented, showing that learning theory is a useful and reliable tool to obtain information about the training process of a given neural network.
HIGH ENERGY PROTON PIXE [HEPP]
Authors: McKEE J.S.C.
Published: November 2004

Studies of particle induced X-ray emission (PIXE) have been widespread and detailed in recent years and despite the fact that most data obtained are from low energy 1–3 MeV experiments, the value of higher energy proton work with its emphasis on K X-ray emission has become more marked as time has progressed. The purpose of this review paper is to outline the history of analysis using high energy protons and to compare and contrast the results obtained with those from lower energy analysis using more firmly established analytical techniques. The work described will concentrate exclusively on proton induced processes and will attempt to outline the rationale for selecting an energy, greater than 20 and up to 70 MeV protons for initiating particles. The relative ease and accuracy of the measurements obtained will be addressed. Clearly such X-ray studies should be seen as complementing low energy work in many instances rather than competing directly with them. However, it will be demonstrated that above a Z value of approximately 20, K X-ray analysis using high energy protons is the only way to go in this type of analysis.
SEMICLASSICAL STUDY OF δ-ELECTRON SPECTRA
Authors: GERASIMOV S.A.
Published: November 2004

This short communication contains an analytical expression for secondary-electron spectra. The obtained solution is confirmed by comparison with experimental data and analytical calculation of the Livingstone-Bethe asymptotics.
A FEW APPROACHES TO REMOVE AMBIGUOUS FACTORS IN X-RAY SPECTRUM ANALYSIS
Authors: SERA K. , FUTATSUGAWA S.
Published: November 2004

A few attempts have been done to reduce ambiguous factors in the analysis of complex x-ray spectra. Uncertainty in peak identification and separation due to overlapping of x-ray peaks can be reduced by taking into account the response function of x-ray peaks and by using peak functions including all the x-ray sub-lines in a x-ray series. Ambiguous factors due to discontinuity of backgrounds which is sometimes followed by huge peaks can be reduced by considering contributions from the pile-up, escape and tail functions. The problem of uncertainty in the background fitting in a region of low x-ray energy, where many peaks overlap each other and determination of the background function contains much difficulties and ambiguities, can be solved by using peak functions involving tails in place of Gaussians.
MICRO PIXE ANALYSIS USING AN X-RAY FROM INCIDENT IONS
Authors: MOKUNO Y. , HORINO Y. , KINOMURA A. , CHAYAHARA A. , FUJII K.
Published: November 2004

A possibility of using an X-ray from incident ions in micro PIXE measurement with MeV heavy ions was discussed. To reveal the feature, a Cu-Ti plate was analyzed by a 5 MeV silicon and a 5 MeV nickel ion microprobe and the PIXE-mapping images of the X-rays from the incident ions were compared with the normal PIXE-mapping images of the X-rays from the target. These images indirectly reflected the distribution of a specific element with good statistics.
CONTRIBUTION OF ECC, ELC, AND TI TO CUSP ELECTRONS IN COLLISION BETWEEN He+ AND Ar TARGET
Authors: Hsu C.C. , Depaola B.D. , Chu T.C. , Chang Y.C. , Jaw K.L.
Published: November 2004

The contributions of ECC, ELC and TI to cusp electrons are measured from 40 keV to 100 keV of projectile He + energies. While the contribution of the ELC is so small and decreases as the energy of projectile decreases, the contribution of TI increases slowly and becomes constant finally.

The ratio of the contribution of TI to that of ECC remains approximately constant in the energy region. This fact implies that there is a linear correlation between the cusp electrons of processes TI and those of ECC.
VERY HIGH SPEED OEIC TRANSMITTERS FOR FUTURE OPTICAL TRANSMISSION SYSTEMS AND OPTICAL NETWORKS
Authors: LO Y.H. , LEE T.P.
Published: November 2004

The technology and system applications of high speed OEIC transmitters are discussed in this paper. With only two MOCVD growths and conventional processing techniques, OEIC transmitters made of sophisticated DFB laser diodes and InGaAs/InAlAs MODFETs can be fabricated. A speed of 10 Gbit/s has been demonstrated. Using the same technology, OEIC transmitters for high bit rate time division multiplexed (TDM) and dense wavelength division multiplexed (WDM) systems are designed and fabricated. There is evidence showing that the OEIC transmitter integrated with multiplexers and other critical circuits can offer significant cost reduction and performance improvement compared to hybrid approach. Using a four-channel OEIC WDM transmitter, we demonstrate its capability of precise wavelength control by setting the channel spacing as close as 0.3 nm. Finally, the crosstalk of OEIC is analyzed. Bonding wires are confirmed as the dominant factor for RF crosstalk. To keep the thermal crosstalk within an acceptable level, a proper device spacing to substrate thickness ratio has to be chosen.
DYNAMIC GaAs LOGIC CIRCUITS
Authors: HOE DAVID H.K. , SALAMA C. ANDRE T.
Published: November 2004

Because of their ratioless nature, dynamic logic has several advantages over conventional static techniques used in GaAs . The ability to implement complex gates with dynamic logic leads to circuits with increased speed and reduced power dissipation. Several dynamic configurations using GaAs MESFETs are reviewed. The main challenge is to overcome leakage currents associated with the Schottky gate junctions in order to allow reliable dynamic operation. The pipelining of GaAs dynamic circuits, which allows full use of the clock cycle and improves system throughput, is also discussed. The feasibility of using these dynamic designs in GaAs is illustrated through the design and implementation of complex functional blocks.
THE RECTIFIABLE METRIC ON THE SPACE OF PROJECTIONS IN A C*-ALGEBRA
Authors: CHRISTOPHER PHILLIPS N.
Published: November 2004

Let A be a C*-algebra, and let P(A) be the set of projections in A. If p, q∈P(A) are in the same path component, then their rectifiable distance is the infimum of the lengths of rectifiable paths in P(A) from p to q. We investigate the number cpl (A), defined to be the supremum of the rectifiable diameters of the path components of P(A). It is an analog for projections of Ringrose’s C* exponential length cel (A), and is also more directly related to it; for example, we show that cpl (A)≤ cel (A) for unital A. We give upper bounds for cpl (A) for most of the classes of algebras for which the C* exponential length and rank have been studied so far; our results are often stronger or more general than the corresponding results for C* exponential length and rank. We also introduce the quantity cpr (A), which is essentially determined by cpl (A) and which, unlike cpl (A), generalizes to give an interesting invariant bpr (A) for Banach algebras A. For a C*-algebra A, we prove that cpr (A)/3≤ bpr (A)≤ cpr (A)+1.
ON THE EXISTENCE OF CLOSED GEODESICS ON TWO-SPHERES
Authors: BANGERT VICTOR
Published: November 2004

In [7] J. Franks proves the existence of infinitely many closed geodesics for every Riemannian metric on S2 which satisfies the following condition: there exists a simple closed geodesic for which Birkhoff's annulus map is defined. In particular, all metrics with positive Gaussian curvature have this property. Here we prove the existence of infinitely many closed geodesics for every Riemannian metric on S2 which has a simple closed geodesic for which Birkhoff's annulus map is not defined. Combining this with J. Franks's result and with the fact that every Riemannian metric on S2 has a simple closed geodesic one obtains the existence of infinitely many closed geodesics for every Riemannian metric on S2.
THE DISCONTINUITY SET FOR A KLEINIAN GROUP AND TOPOLOGY OF ITS KLEINIAN MANIFOLD
Authors: TETENOV ANDREW V.
Published: November 2004

The aim of the paper is to proof the finiteness theorems for the discontinuity set Ω (G) of Kleinian groups G on n-sphere, n ≥ 3 and to study the relation between the structure of Ω (G) and the topology of infinite volume hyperbolic (n + 1)-manifold M (G), π1 (M) = G. In particular, we describe the homotopy and homology of these manifolds.
EXTENSIONS BY C*-ALGEBRAS WITH REAL RANK ZERO
Authors: LIN HUAXIN
Published: November 2004

We show that all trivial (unital and essential) extensions of C (X) by a σ-unital purely infinite simple C*-algebra A with K1(A) = 0 are unitarily equivalent, provided that X is homeomorphic to a compact subset of the real line or the unit circle. Therefore all (unital and essential) extensions of such can be completely determined by Ext(B, A). An invariant is introduced to classify all such trivial (unital and essential) extensions of C (X) by a σ-unital C*-algebra A with the properties that RR (M (A)) = 0 and C (A) is simple.
A NOTE ON OCNEANU'S APPROACH TO JONES' INDEX THEORY
Authors: YAMAGAMI SHIGERU
Published: November 2004

Some of the basic facts in the Ocneanu's approach to Jones' index theory are proved. Among other things the biunitarity of connections in paragroups is proved generally by making use of Frobenius reciprocity.
Parallel Monte Carlo Algorithms for Domain Growth Kinetics
Authors: SCHLEIER W. , BESOLD G. , HEINZ K.
Published: November 2004

We study the applicability of parallelized Monte Carlo algorithms to the simulation of domain growth in 2-dim. lattice gas models after a quench into an ordered phase. Conventional parallelized algorithms with KAWASAKI dynamics introduce artificial spatial correlations into the system. However, only if superstructure domains evolve, these correlations will modify the kinetics by influencing the nucleation process and result in a reduced kinetic exponent. Two improved algorithms with slightly reduced degree of parallelism suitable for simulation of superstructure domain growth are presented and discussed.
THE CONNECTION MACHINE AT THE UNIVERSITY OF PARMA
Authors: ADORNI GIOVANNI , CONTE GIANNI
Published: November 2004

This note presents the site in Parma where the Connection Machine CM-2 is located, the reasons for its acquisition in the framework of the EUREKA PROMETHEUS project, and the list of the current research activities carried on using the Connection Machine.
BASIC SPARSE MATRIX COMPUTATIONS ON THE CM-5
Authors: PETITON SERGE , SAAD YOUCEF , WU KESHENG , FERNG WILLIAM
Published: November 2004

This paper presents a preliminary experimental study of the performance of basic sparse matrix computations on the CM-5. We concentrate on examining various ways of performing general sparse matrix-vector operations and the basic primitives on which these are based. We compare various data structures for storing sparse matrices and their corresponding matrix — vector operations. Both SPMD and Data parallel modes are examined and a comparison of the two modes is made.
ENVIRONMENTS FOR PARALLEL ARCHITECTURES
Authors: QUECKE GERHARD
Published: November 2004

This paper describes the facilities of the Laboratory for Parallel Systems at Germany's national institute for computer science. It gives an overview of the parallel machines installed in the laboratory, the environment they are embedded in and their usage, especially the usage of the Connection Machine.
THE CONNECTION MACHINE IN A UNIVERSITY ENVIRONMENT: GESAMTHOCHSCHULE WUPPERTAL
Authors: SCHILLING KLAUS
Published: November 2004

A short account is presented on the early history, the intentions and the development of large scale parallel computing at the University of Wuppertal. It might serve as an illustration how common activities between computational and computer science can be stimulated, in the university environment.
LATTICE QUANTUM ELECTRODYNAMICS NEAR THE PHASE TRANSITION
Authors: LIPPERT THOMAS
Published: November 2004

Numerical simulations of quantum electrodynamics near the phase transition suffer from an extreme slowing down on large lattices. The two leading terms of the decaying autocorrelation function can be attributed to the influence of first-order phase transition effects, called supercritical slowing down, and second-order phase transition effects, called critical slowing down, respectively. We show that we can bypass supercritical slowing down using a conventional local updating algorithm based on a phenomenological weight ratio fixing method.

As for critical slowing down, we apply a new global multi-scale updating algorithm which removes critical slowing down completely. We compare the structure of the local vs. the global algorithm as well as their implementation on the Connection Machine CM-2, analyze their computational complexity and present actual performance measurements.
NEURAL MULTIGRID METHODS FOR GAUGE THEORIES AND OTHER DISORDERED SYSTEMS
Authors: BÄKER M. , KALKREUTER T. , MACK G. , SPEH M.
Published: November 2004

We present evidence that multigrid works for wave equations in disordered systems, e.g. in the presence of gauge fields, no matter how strong the disorder, but one needs to introduce a "neural computations" point of view into large scale simulations: First, the system must learn how to do the simulations efficiently, then do the simulation (fast). The method can also be used to provide smooth interpolation kernels which are needed in multigrid Monte Carlo updates.
MULTICANONICAL MONTE CARLO SIMULATIONS
Authors: BERG BERND A.
Published: November 2004

The multicanonical ensemble is reviewed. Simulations of this ensemble promise improvements for a wide range of systems. Applications to first order phase transitions and spin glasses are summarized.
Quasi-Monte Carlo, quasi-random numbers and quasi-error estimates
Authors: Kleiss Ronald
Published: November 2004

We discuss quasi-random number sequences as a basis for numerical integration with potentially better convergence properties than standard Monte Carlo. The importance of the discrepancy as both a measure of smoothness of distribution and an ingredient in the error estimate is reviewed. It is argued that the classical Koksma-Hlawka inequality is not relevant for error estimates in realistic cases, and a new class of error estimates is presented, based on a generalization of the Woźniakowski lemma.
CONVODE: A REDUCE PACKAGE FOR DIFFERENTIAL EQUATIONS
Authors: MOUSSIAUX ALAIN , MAIRESSE RICHARD
Published: November 2004

The package CONVODE (CONVersion of Ordinary Differential Equations) is written in REDUCE 3.4 in order to study differential equations and systems of differential equations. Differential equations (D.E.) whose solutions can be obtained using CLASSICAL methods of integration are investigated. CONVODE is written on the framework of most of the textbook on D.E. One of the characteristics of CONVODE is to be a very wordy program and to keep its user aware of its process.
INVERSION OF THE FERMION MATRIX IN LATTICE QCD BY MEANS OF PARALLEL-TRANSPORTED MULTIGRID (PTMG)
Authors: LAUWERS P. G. , WITTLICH T.
Published: November 2004

The standard PTMG method, invented and tested for the inversion of the fermion matrix (Dirac-operator) in the case of U(1) and SU(2) lattice gauge theories with staggered fermions, has now been generalized to SU(3). A crucial ingredient of the new algorithm is the way SU(3) link elements are averaged in the generation of the coarse grid link elements. Numerical results are presented for the two-dimensional case. For 128 × 128 lattices and physically relevant values of the coupling constant β and of the quark mass mq, the new algorithm is an order of magnitude faster in CPU time than its leading competitor, the Conjugate-Gradient algorithm.
ASSESSMENT OF NONEQUILIBRIUM RADIATION COMPUTATION METHODS FOR HYPERSONIC FLOWS
Authors: SHARMA SURENDRA P.
Published: November 2004

The present understanding of shock-layer radiation in the low density regime, as appropriate to hypersonic vehicles, is surveyed. Based on the relative importance of electron excitation and radiation transport, the hypersonic flows are divided into three groups: weakly ionized, moderately ionized, and highly ionized flows. In the light of this division, the existing laboratory and flight data are scrutinized. Finally an assessment of the nonequilibrium radiation computation methods for the three regimes in hypersonic flows is presented. The assessment is conducted by comparing experimental data against the values predicted by the physical model.
HIERARCHICAL TREE-STRUCTURES AS ADAPTIVE MESHES
Authors: EDELSOHN DAVID J.
Published: November 2004

New adaptive mesh refinement algorithms provide an opportunity to utilize the same hierarchical tree-structures developed for multipole-based particle simulations in grid-based simulations of both continuum and particle problems. Representing both a multipole method simulation and an adaptive mesh simulation with this same structure provides a natural formalism with which to unite these two classes of solvers. This paper discusses how both methods exploit the same basic principle of locality evident in many systems, such as those governed by Poisson's Equation, and introduces issues and potential problems to be addressed in an implementation. The locality of the systems and the resulting algorithms provide important benefits for implementations on massively parallel computers.
A HARDWARE IMPLEMENTATION OF THE APE100 ARCHITECTURE
Authors: BARTOLONI A. , BASTIANELLO G. , BATTISTA C. , CABASINO S. , MARZANO F. , PAOLUCCI P. S. , PECH J. , RAPUANO F. , PANIZZI E. , SARNO R. , TODESCO G. M. , TORELLI M. , TROSS W. , VICINI P. , CABIBBO N. , FUCCI A. , TRIPICCIONE R.
Published: November 2004

APE100 processors are based on a simple Single Instruction Multiple Data architecture optimized for the simulation of Lattice Field Theories or other complex physical systems. This paper describes the hardware implementation of the first APE100 machine.
PARALLEL IMPLEMENTATION OF 3 + 1-DIMENSIONAL RELATIVISTIC HYDRODYNAMICS
Authors: DEAN D. J. , BOTTCHER C. , STRAYER M. R. , WELLS J. C.
Published: November 2004

We discuss the parallel implementation of 3 + 1-dimensional relativistic hydrodynamics. The discretization of these equations is performed with a basis-spline collocation method. An iterative procedure for the time evolution will also be discussed. Approximately 60% of the computational effort is spent in performing vector-matrix multiplications that may easily be vectorized. Furthermore, for large lattices, these operations may be spread across the nodes of a parallel machine. We show how to accomplish this partitioning for the hydrodynamic evolution equations. A double-ring, message-passing algorithm is shown to enhance overall code performance when compared to a single ring on iPSC/i860 architectures. Overall code performance is discussed, and an application to relativistic nuclear collision physics is presented.
GREEN–FUNCTION METHOD FOR ELECTRONIC STRUCTURE OF PERIODIC CRYSTALS
Authors: ZELLER R.
Published: November 2004

A new Green–function program for electronic–structure calculations for periodic crystals in shortly described and some modifications necessary for using the Intel iPSC/860 are given. The computing power of the iPSC/860 for the total–energy calculation of fcc Cu is compared to various other computers.
MONTE CARLO SIMULATION OF A 3-D FRUSTRATED HEISENBERG MODEL
Authors: BILLOIRE ALAIN
Published: November 2004

I present simulations of the classical antiferromagnetic Heisenberg model on a 3-D stacked triangular lattice. The program simulates three independent systems, one third of each system being updated in parallel. It performs between 600 and 800 MegaFlops on a 32 nodes CM-5.
DETERMINATION OF MONOPOLE CURRENT CLUSTERS IN FOUR-DIMENSIONAL QUANTUM ELECTRODYNAMICS
Authors: BODE ACHIM , LIPPERT THOMAS , SCHILLING KLAUS , UEBERHOLZ PEER
Published: November 2004

Magnetic monopole currents are believed to have a strong impact on the Monte Carlo dynamics of compact quantum electrodynamics near the phase transition. We have indications that updating algorithms have to form and to break up monopole current clusters in order to force the tunneling of the system between the coexisting phases, the confined phase and the Coulomb phase. This might be responsible for long lived metastabilities in the time series.

We present parallel numerical algorithms which allow the fast identification of clusters of monopole loops, the determination of their topological properties as well as their visualization in the course of a Monte Carlo simulation. The algorithms are implemented on the Connection Machine CM-5. We compare the data parallel programming style with a message passing approach. Complexity and performance are discussed.
ASSEMBLY LANGUAGE PROGRAMMING FOR THE 1860
Authors: BOOTH STEPHEN
Published: November 2004

The structure of the i860 is reviewed briefly. The code generation strategies used by compilers and assembly language programmers are compared. The problems associated with generating efficient code for the i860 are highlighted and a case study from QCD is used to demonstrate these points. Timing results for the case study are presented.
CONJUGATE GRADIENTS PARALLELIZED ON THE HYPERCUBE
Authors: BASERMANN ACHIM
Published: November 2004

For the solution of discretized ordinary or partial differential equations it is necessary to solve systems of equations with coefficient matrices of different sparsity pattern, depending on the discretization method; using the finite element method (FE) results in largely unstructured systems of equations. A frequently used iterative solver for systems of equations is the method of conjugate gradients (CG) with different preconditioners. On a multiprocessor system with distributed memory, in particular the data distribution and the communication scheme depending on the used data struture are of greatest importance for the efficient execution of this method. Here, a data distribution and a communication scheme are presented which are based on the analysis of the column indices of the non-zero matrix elements. The performance of the developed parallel CG-method was measured on the distributed-memory-system INTEL iPSC/860 of the Research Centre Jülich with systems of equations from FE-models. The parallel CG-algorithm has been shown to be well suited for both regular and irregular discretization meshes, i.e. for coefficient matrices of very different sparsity pattern.
WORKSTATION CLUSTERS: ONE WAY TO PARALLEL COMPUTING
Authors: WEBER MICHAEL
Published: November 2004

The feasibility and constraints of workstation clusters for parallel processing are investigated. Measurements of latency and bandwidth are presented to fix the position of clusters in comparison to massively parallel systems. So it becomes possible to identify the kind of applications that seem to be suited for running on a cluster.