bluuebunny/crossref_metadata_2025 huggingface dataset:
Verticillium longisporum and Fusarium solani: two new species in the complex of internal discoloration of horseradish roots
Authors: Babadoost M. , Chen W. , Bratsch A. D. , Eastman C. E.
Published: November 2004

This study was conducted to determine the causal agent(s) of internal discoloration of horseradish roots. In 1999, 133 roots from 31 fields, and in 2000, 108 roots from nine fields, were assayed to determine the incidence and severity of internal discoloration of horseradish roots as well as the pathogen(s) associated with discoloured tissue. Verticillium dahliae, Verticillium longisporum and Fusarium solani were isolated from 14, 16 and 23% of roots in 1999, and from 24, 20 and 19% of roots in 2000, respectively. Verticillium longisporum on horseradish was identified for the first time. Pathogenicity tests of isolated microorganisms were conducted on horseradish in the glasshouse. In one experiment on the susceptible cultivar 1573, roots (sets) were inoculated by dipping the sets in a suspension of either V. dahliae microsclerotia, V. longisporum microsclerotia, or F. solani conidia and then grown in a soil mix over 5 months. Plants inoculated with any of the three species developed root discoloration similar to that observed in commercial fields. Internal root discoloration symptoms developed over a period of 5 months. For all three pathogens, severity of root discoloration was significantly higher after 5 months compared with 2 months from inoculation. In another experiment on cultivar 1590, tissue culture‐generated seedlings and sets were planted in an infested soil mix with V. dahliae or V. longisporum and grown in the glasshouse. Plants developed root discoloration, as observed in the field. The pathogens were reisolated from inoculated plants in both experiments. No pathogen was isolated from the control plants in the experiments. The results of this study suggest that internal discoloration of horseradish roots is a disease complex caused by at least three fungal species.
E–W opening of the Algerian Basin (Western Mediterranean)
Authors: Mauffret A. , Frizon de Lamotte D. , Lallemant S. , Gorini C. , Maillard A.
Published: November 2004

We present geophysical and geological evidence of fast (2 cm yr−1in the east and 5 cm yr−1in the west) E–W spreading between 16 and 8 Ma in the region behind the Gibraltar Arc in the Algerian Basin.
Palaeomagnetic constraints on the geodynamic evolution of the Gibraltar Arc
Authors: Krijgsman Wout , Garcés Miguel
Published: November 2004

Subduction zone roll‐back was recently put forward as a convincing model to explain the geometry and evolution of the Gibraltar Arc. For other subduction‐related arc systems of the Mediterranean, such as the Calabrian Arc and the Hellenic Arc, palaeomagnetic rotation data from Neogene extensional basins provided important constraints on geodynamic evolution models. Here, we present the results of a palaeomagnetic study of 13 continuous sections that are located in E–W transects across the Neogene sedimentary basins of Morocco and Spain. They provide evidence that no significant rotation about vertical axes has occurred in the Gibraltar Arc since the late Tortonian. Comparison with other Mediterranean arc systems shows strong similarities as regards geodynamic evolution. The timing of rotation in the Gibraltar Arc is markedly older than in the Calabrian and Hellenic arcs, and suggests that it is related to the first Neogene extensional phase of the western Mediterranean in which the Algerian–Provençal Basin opened.
Geometry and kinematics of recent deformation in the Mondy–Tunka area (south‐westernmost Baikal rift zone, Mongolia–Siberia)
Authors: Arjannikova A. , Larroque C. , Ritz J. ‐F. , Déverchère J. , Stéphan J. F. , Arjannikov S. , San'kov V.
Published: November 2004

We used satellite imagery and field data to investigate the south‐westernmost Baikal rift zone. We focus our study in the Mondy and Ikhe Ukhgun valleys, site of an Mw = 6.9 seismic event in 1950. Surface deformations are observed along the E–W‐trending Mondy strike‐slip fault and along the Ikhe Ukhgun thrust. The Mondy fault system is 80 km long and is composed of four segments 10–15 km long. These segments are characterized by subvertical planes with left‐lateral movements. The Ikhe Ukhgun thrust is 20 km long, dips 40° to the south and shows reverse movement with a left‐lateral component. These observations are consistent with the present‐day regional NNE–SSW compression and with the focal mechanism of the 1950 Mondy earthquake that was recently re‐evaluated. These features, like those observed in the Tunka basin, demonstrate a recent change of regional strain regime from transtension to transpression that we place before the Late Pleistocene.
Strategies for Good Governance in the Pacific
Authors: Saldanha Cedric
Published: November 2004

Governance problems in the Pacific find their roots in deeply embedded political and social issues such as the structures of government, the quality of leadership, and the capacity of civil society to hold government accountable. These root causes are not easily addressed by outsiders, such as donors. Yet, governance is so fundamental to the development process that development agencies have a responsibility to assist. The options available to them are relatively limited, however, given that sustained change can only occur if driven from within. But there are courses of action available to development agencies and this paper has outlined a few. They do not necessarily need substantial amounts of funding. But they do need persistent and continuing effort and support and a substantial change of strategy by donors.
Child Labour: a survey of selected Asian countries
Authors: Ray Ranjan
Published: November 2004

While the African continent has the highest child labour force participation rates, Asia contains the largest pool of child workers. The nature, magnitude and decline in child labour vary sharply between Asian countries. East Asia now has little child labour; however, child labour continues to have a significant presence in South Asia and in parts of Southeast Asia. This paper surveys the literature on child labour in selected Asian countries, paying special attention to its causes and consequences. The evidence presented shows that Asian child labour, especially in South and Southeast Asia, has some common features. For example, the bulk of child labour is in the 10–14 years age group. The phenomenon is largely rural, and child domestic labour constitutes a significant share. The participation rate of Asian children in the 15–17 years age group in economic activities, 48.4 per cent, is the highest in the world. There is a significant gender element in Asian child labour with boys outnumbering girls in economically active work, while the reverse is the case with domestic child labour. A focus of the survey is the empirical findings that provide insights into the policy instruments that may be needed in combating this phenomenon. The survey also discusses some of the important international and national initiatives that have been taken to reduce child labour.
Radiographic examination of the mandibular (glenoid) fossa in ancient and modern man
Authors: Tanaka T , Morimoto Y , Tanaka Y , Kobayashi S , Okumura Y , Kito S , Okabe S , Ohba T
Published: November 2004

Objective:  To compare the morphology of the mandibular (glenoid) fossa between ancient and modern Japanese.

Methods:  There were 221 specimens from the ancient period and 206 specimens from the modern period. Radiographs of the mandibular fossa were obtained using a modified Schüller technique and were studied. The length, depth, and area of the mandibular fossa and angulation of the frontal slope of the mandibular fossa on the radiographs were automatically computed. In addition, morphological changes of the mandibular fossa in the ancient or modern periods on radiographs were evaluated in order to assess tendency of temporomandibular joint disorder (TMD).

Result:  The ratio of mandibular fossa having morphological alternation in the modern period was greater than that in the Yayoi. Differences in the length and area between the right and left sides became progressively larger from the Yayoi to modern periods. The angulation of the anterior slope of the mandibular fossa in the modern period was smaller than that in other periods.

Conclusion:  The morphology of the mandibular fossa was shown to have changed and asymmetry has increased from the Yayoi to modern periods. It can be speculated that this change in morphology of the mandibular fossa in the modern period is the result of an increase of TMD.
Somato‐dendritic nicotinic receptor responses recorded in vitro from the medial septal diagonal band complex of the rodent
Authors: Henderson Zaineb , Boros András , Janzso Gergely , Westwood Andrew J. , Monyer Hannah , Halasy Katalin
Published: November 2004

The medial septal diagonal band area (MS/DB), made up of GABAergic and cholinergic neurones, plays an essential role in the generation and modulation of the hippocampal theta rhythm. To understand the part that the cholinergic neurones might play in this activity, we sought to determine whether postsynaptic nicotinic receptor responses can be detected in slices of the rodent MS/DB by puffing on acetylcholine (ACh). Neurones were characterized electrophysiologically into GABAergic and cholinergic neurones according to previous criteria. Responses of the MS/SB neurones to ACh were various combinations of fast depolarizations (1.5–2.5 s), fast hyperpolarizations (3–4 s) and slow depolarizations (20–30 s), the latter two being blocked by atropine. The fast depolarizations were partially or not blocked with cadmium and low calcium, tetrodotoxin, and antagonists of other ionotropic receptors, and were antagonized with 25 μm mecamylamine. Pharmacological investigation of the responses showed that the α7* nicotinic receptor type is associated with cholinergic neurones and 10% of the GABAergic neurones, and that nonα7* nicotinic receptor subtypes are associated with 50% of the GABAergic neurones. Pharmacological dissection of evoked and spontaneous postsynaptic responses, however, did not provide evidence for synaptic nicotinic receptor transmission in the MS/DB. It was concluded that nicotinic receptors, although prevalent on the somatic and/or dendritic membrane compartments of neurones in the MS/DB, are on extrasynaptic sites where they presumably play a neuromodulatory role. The presence of α7* nicotinic receptors on cholinergic neurones may also render these cells specifically vulnerable to degeneration in Alzheimer's disease.
Effects of wetting ability of plating electrolyte on Cu seed layer for electroplated copper film
Authors: Liu Chi-Wen , Tsao Jung-Chih , Tsai Ming-Shih , Wang Ying-Lang
Published: November 2004

This work examines the impact of the wetting ability of a plating electrolyte on the Cu seed layer on copper electroplating performance. The contact angle of the electrolyte on the Cu seed is highly sensitive to additive decomposition in the electrolyte, as well as being sensitive to Cu seed self-annealing. The contact angle of the electrolyte decreases in the presence of polyethylene glycol (PEG), which forms complexes with chloride ions and is absorbed on the Cu surface during plating. However, the consumption of the additives, particularly that of chloride ions, degrades this adsorption. Additionally, the increase in Cu-seed surface roughness owing to self-annealing also reduces electrolyte wettability, compared to the as-received Cu-seed layer. The poor wettability can be improved with additional rinsing. The x-ray photoelectron spectroscopy (XPS) spectrum demonstrates that the Cu surface was covered with a native cupric-hydroxide layer after rinsing, which was hydrophilic (as in the aqueous-plating bath) and had improved wettability. This study also correlates the contact angle with the trapped defects in the electroplated film, which in turn influence the electrical characteristics of the interconnection. The experimental results show that the poor wettability of the plating electrolyte on the Cu seed significantly influences the fluctuations of the Cu interconnect resistance. This conclusion is valuable in designing Cu damascene processes.
Structure characterization and photon absorption analysis of carbon-doped β-FeSi2 film
Authors: Li Xiaona , Nie Dong , Dong Chuang , Xu Lei , Zhang Ze
Published: November 2004

Carbon-doped β–FeSi2 films synthesized by ion implantation are investigated with the aim to fabricate high-quality semiconducting β–FeSi2 layer on silicon substrate. According to transmission electron microscopy (TEM) cross-section observations, carbon-doped films with homogeneous thickness and smooth β–Si interface, have higher quality than binary Fe–Si films. In particular, annealing at 500°C–700°C leads to the formation of a flat and continuous β-type silicide layer. Improved stability of the β phase is also found. Optical emission spectroscopy measurements show that the carbon doping influences only slightly the band gap values.
Effect of pressure on the deposition of hydrogen-free amorphous carbon and carbon nitride films by the pulsed cathodic arc discharge method
Authors: Liu Dongping , Benstetter Günther , Wang Wenchun , Zhang Jialiang
Published: November 2004

Hydrogen-free amorphous carbon (a-C) and carbon nitride (a-C:N) films were deposited using the pulsed cathodic arc discharge at different argon and nitrogen pressures. The surface and mechanical properties of these films were found to strongly depend on the gas pressure. The tetrahedral amorphous carbon and hard a-C:N films with smooth surfaces (rms roughness: 0.15nm) were prepared at lower gas pressures (<6×10−2Pa). Incorporation of an increasing amount of nitrogen in a-C:N films caused a decrease in film hardness. All the films were covered with the thin (0.3–2nm) graphite-like surface layers. The film hardness was correlated to the soft surface layer thickness, and the films with thinner surface layers exhibit higher hardness. The mean energies of pulsed plasma beams were measured as the functions of argon and nitrogen pressures. The mean energies of plasma beams decrease in an exponential fashion with increasing gas pressure due to the carbon ion collisions with the neutral gas species. The effects of mean energies of deposited species on the film deposition were explained in terms of the thermal spike migration of surface atoms. The formation of graphite-like surface layers is associated with the low-energy deposition process. The low-energy (<1–3eV) species diffusing on film surface lead to the formation of graphite-like a-C films with plenty of grains. The higher-energy (>10eV) species may produce the strong thermal spike at film surface, and contribute to the formation of sp3 bonded structure at a sp3 bonded matrix.
Vacuum beam studies of fluorocarbon radicals and argon ions on Si and SiO2 surfaces
Authors: Kimura Yoshie , Coburn J. W. , Graves David B.
Published: November 2004

Si and SiO2 were exposed to c-C4F8 with and without Ar+, and to a mixture of characterized CxFy radical and stable species with and without Ar+. The mixture of CxFy radical and stable species was created from c-C4F8 and Ar plasma and included CF, CF2, CF3, and various heavy CxFy species. The neutral fluorocarbon flux to Ar+ flux and the energy of the Ar+ were varied. During the exposure, etch/deposition rates were measured and the flux of CxFy species leaving the surface for various conditions were qualitatively determined. The following were observed: (1) c-C4F8 is an etchant with Ar+ bombardment; (2) the CF, CF2, and CF3 species flux cannot account for the observed mass increase during depositing conditions; (3) CF2 and CF3 species are net products during etching conditions; and (4) the flux of large CxFy species leaving the surface is smaller during etching conditions than for depositing conditions. These observations imply that large CxFy species play a significant role in the surface chemistry.
Evaluation of the Etest Method Using Mueller-Hinton Agar with Glucose and Methylene Blue for Determining Amphotericin B MICs for 4,936 Clinical Isolates of
Candida
Species
Authors: Pfaller M. A. , Boyken L. , Messer S. A. , Tendolkar S. , Hollis R. J. , Diekema D. J.
Published: November 2004

The performance of the Etest using Mueller-Hinton agar supplemented with glucose (2%) and methylene blue (0.5 μg/ml) (MH-GMB) for amphotericin B susceptibility testing of 4,936 isolates of
Candida
spp. was assessed against that of Etest using RPMI agar with 2% glucose (RPG). MICs were determined by Etest in both media for all 4,936 isolates and were read after incubation for 48 h at 35°C. The
Candida
isolates included
C. albicans
(
n
= 2,728),
C. glabrata
(
n
= 722),
C. parapsilosis
(
n
= 666),
C. tropicalis
(
n
= 528),
C. krusei
(
n
= 143),
C. lusitaniae
(
n
= 54),
C. guilliermondii
(
n
= 39),
C. pelliculosa
(
n
= 17),
C. kefyr
(
n
= 15),
C. rugosa
(
n
= 11),
C. dubliniensis
(
n
= 5),
C. zeylanoides
(
n
= 4),
C. lipolytica
(
n
= 3), and
C. famata
(
n
= 1). The Etest results with MH-GMB correlated well with those with RPG. Overall agreement was 92.9%, and agreements for individual species were as follows:
C. lusitaniae
, 98.1%;
C. albicans
, 95.1%;
C. glabrata
, 94.3%;
C. krusei
, 91.6%;
C. parapsilosis
, 86.6%; and
C. tropicalis
, 86.4%. The Etest method using MH-GMB appears to be a useful method for determining amphotericin B susceptibilities of
Candida
species.
New Multiple Antigenic Peptide-Based Enzyme Immunoassay for Detection of Simian Immunodeficiency Virus Infection in Nonhuman Primates and Humans
Authors: Ndongmo C. B. , Switzer W. M. , Pau C. P. , Zeh C. , Schaefer A. , Pieniazek D. , Folks T. M. , Kalish M. L.
Published: November 2004

Infections with human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2, respectively) are zoonotic infections. In Africa, the potential exists for additional cross-species transmissions from at least 33 different species of simian immunodeficiency virus (SIV)-infected nonhuman primates (NHPs) through hunting and butchering of these animals for food. Here we describe a highly sensitive and specific enzyme immunoassay (EIA) with chemically modified, multiple antigenic peptides (MAPs) developed for the detection and discrimination of antibodies to SIV genetic lineages. The SIV EIA was developed by using a comprehensive array of MAPs covering two envelope gene regions from all of the SIV lineages for whichenvsequences were available. Assay sensitivity was evaluated by using 63 plasma or serum samples obtained from primates naturally or experimentally infected with SIVs from 10 genetic lineages. Assay specificity was determined by using 97 known SIV-negative plasma specimens from these same species. Also used in the evaluations were 369 human samples: 198 HIV seronegative, 170 HIV-1 and/or HIV-2 seropositive, and 1 from a human SIVsm infection. Overall assay sensitivity and specificity were 100% with both immunodominant region (IDR) and V3 region MAPs. Although SIVenvsequences from talapoin monkeys were not available for specific MAP inclusion, 5 (100%) of 5 SIVtal-infected samples were detected through cross-reactivity with other SIV IDR MAPs used in the assay. The one human SIVsm infection was identified. In conclusion, our SIV MAP EIA proved to be highly sensitive and specific for detecting SIV infections in NHPs and humans. As shown with SIV-infected talapoin monkeys, this assay has the potential to detect previously unidentified SIV strains and should be suitable for sentinel surveillance for potential new cross-species transmissions of SIVs to humans.
Analysis of Vaginal Acetic Acid in Patients Undergoing Treatment for Bacterial Vaginosis
Authors: Chaudry Amjad N. , Travers Paul J. , Yuenger Jeffrey , Colletta Lorraine , Evans Phillip , Zenilman Jonathan M. , Tummon Andrew
Published: November 2004

A “gold standard” method for the diagnosis of bacterial vaginosis (BV) is lacking. The clinical criteria described by the Amsel technique are subjective and difficult to quantify. Alternatively, the reading of Gram-stained vaginal smears by scoring techniques such as those that use the Nugent or Hay-Ison scoring systems is again subjective, requires expert personnel to perform the reading, and is infrequently used clinically. Recently, a new diagnostic device, the Osmetech Microbial Analyzer—Bacterial Vaginosis (OMA-BV), which determines a patient's BV status on the basis of measurement of the amount of acetic acid present in a vaginal swab specimen, was approved by the Food and Drug Administration. The present study uses the conducting polymer gas-sensing technology of OMA-BV to measure the concentration of acetic acid in the headspace above vaginal swab specimens from patients undergoing treatment for BV with metronidazole. In 97.8% of the cases the level of acetic acid detected fell sharply during the treatment period, crossing from above to below the diagnostic threshold of 900 ppm. The diagnosis obtained on the basis of the level of vaginal acetic acid was compared with the diagnoses obtained by use of the Amsel criteria and the Nugent scoring system both at the time of initial entry into the study and at the repeat samplings on days 7 and 14. The results obtained with OMA-BV showed overall agreements compared with the results of the Amsel and Nugent tests of 98 and 94%, respectively, for the 34 patients monitored through the treatment process. This provides further evidence that the measurement of vaginal acetic acid by headspace analysis with conducting polymer sensors is a valid alternative to present tests for the diagnosis of BV.
Characterization of Bacterial Community Diversity in Cystic Fibrosis Lung Infections by Use of 16S Ribosomal DNA Terminal Restriction Fragment Length Polymorphism Profiling
Authors: Rogers G. B. , Carroll M. P. , Serisier D. J. , Hockey P. M. , Jones G. , Bruce K. D.
Published: November 2004

Progressive loss of lung function resulting from the inflammatory response to bacterial colonization is the leading cause of mortality in cystic fibrosis (CF) patients. A greater understanding of these bacterial infections is needed to improve lung disease management. As culture-based diagnoses are associated with fundamental drawbacks, we used terminal restriction fragment (T-RF) length polymorphism profiling and 16S rRNA clone data to characterize, without prior cultivation, the bacterial community in 71 sputa from 34 adult CF patients. Nineteen species from 15 genera were identified in 53 16S rRNA clones from three patients. Of these, 15 species have not previously been reported in CF lung infections and many were species requiring strict anaerobic conditions for growth. The species richness and evenness were determined from the T-RF length and volume for the 71 profiles. Species richness was on average 13.3 ± 7.9 per sample and 13.4 ± 6.7 per patient. On average, the T-RF bands of the lowest and highest volumes represented 0.6 and 59.2% of the total volume in each profile, respectively. The second through fifth most dominant T-RF bands represented 15.3, 7.5, 4.7, and 2.8% of the total profile volume, respectively. On average, the remaining T-RF bands represented 10.2% of the total profile volume. The T-RF band corresponding to
Pseudomonas aeruginosa
had the highest volume in 61.1% of the samples. However, 18 other T-RF band lengths were dominant in at least one sample. In conclusion, this reveals the enormous complexity of bacteria within the CF lung. Although their significance is yet to be determined, these findings alter our perception of CF lung infections.
Isolation ofBartonella schoenbuchensisfromLipoptena cervi, a Blood-Sucking Arthropod Causing Deer Ked Dermatitis
Authors: Dehio Christoph , Sauder Ursula , Hiestand Rosemarie
Published: November 2004

Bartonella schoenbuchensis, which commonly causes bacteremia in ruminants, was isolated from the deer kedLipoptena cerviand was shown to localize to the midgut of this blood-sucking arthropod, causing deer ked dermatitis in humans. The role ofB. schoenbuchensisin the etiology of deer ked dermatitis should be further investigated.
Effects of catchment characteristics and disturbances on storage and export of dissolved organic carbon in a boreal headwater stream
Authors: Hillman Graham R , Feng Joseph C , Feng Cecilia C , Wang Yonghe
Published: November 2004

The transportation of large amounts of dissolved organic carbon (DOC) down a stream within a 15.51-km2 catchment in Alberta, Canada, related directly to events, such as high rainfall and beaver (Castor canadensis) dam failures, that created major disturbances. A 2.3-km section of the stream was drastically altered in June 1994 when a flood wave resulting from a breached beaver dam deposited large amounts of debris and sediment within the section. Results from stream DOC-storage analyses, in which a difference method was used, suggest that the organic-debris dams created by the failed dam event served as both sources and sinks for DOC. Discharge and DOC measurements at hydrometric stations located at intervals along the stream indicated that storage of DOC on the catchment was strongly influenced by the presence of wetlands and beaver. In 1994 and 1995, disturbances occurring during periods totalling 17 days and 28 days accounted for 94% (1374 kg·km2) and 84% (204 kg·km2), respectively, of the amount of DOC exported from the catchment. DOC concentrations in the stream were greatest (77.0 mg·L1) near the top of the catchment and decreased progressively downstream to the catchment outlet, where the mean concentration was 23.3 mg·L1.
Thermodynamic properties of 1,1,1,2-tetrafluoroethane + polyether mixtures up to 60 MPa
Authors: Comuñas M JP , Boned C , Baylaucq A , López E R , Fernández J
Published: November 2004

In this work we report several derived thermodynamic properties, the isothermal compressibility (κT), the isobaric thermal expansion coefficient (αp), and the internal pressure (π), and their excess functions (κTE, αpE, and πE) for the refrigerant + lubricant mixtures HFC-134a + triethylene glycol dimethyl ether and HFC-134a + tetraethylene glycol dimethyl ether. These properties have been determined in wide temperature (293.15373.15 K) and pressure (1060 MPa) ranges in an effort to better understand the behaviour of these kinds of mixtures and their thermophysical properties as functions of temperature, pressure, and composition. The analysis of the thermodynamic excess properties (negative values for κTE and αpE, positive values for πE) for both systems shows a high degree of interaction between the refrigerant and the synthetic lubricant molecules. Key words: HFC-134a, high pressure, internal pressure, isobaric thermal expansion coefficient, isothermal compressibility, polyglycol ethers, refrigerantlubricant mixtures.
PREDICTING CONDITIONAL PROBABILITY DISTRIBUTIONS: A CONNECTIONIST APPROACH
Authors: WEIGEND ANDREAS S. , SRIVASTAVA ASHOK N.
Published: November 2004

Most traditional prediction techniques deliver a single point, usually the mean of a probability distribution. For multimodal processes, instead of predicting the mean, it is important to predict the full distribution. This article presents a new connectionist method to predict the conditional probability distribution in response to an input. The main idea is to transform the problem from a regression problem to a classification problem. The conditional probability distribution network can perform both direct predictions and iterated predictions, the latter task being specific for time series problems. We compare this new method to fuzzy logic and discuss important differences, and also demonstrate the architecture on two time series. The first is the benchmark laser series used in the Santa Fe competition, a deterministic chaotic system. The second is a time series from a Markov process which exhibits structure on two time scales. The network produces multimodal predictions for this series. We compare the predictions of the network with a nearest-neighbor predictor and find that the conditional probability network is more than twice as likely a model.
USING THE POTTS GLASS FOR SOLVING THE CLUSTERING PROBLEM
Authors: BENGTSSON MATS , ROIVAINEN PERTTI
Published: November 2004

We present an application of a Potts glass to the clustering problem. Simulated annealing in the mean field approximation is used in order to avoid local minima. The resulting updating equations are completely parallel, and very easy to implement. The model has no free parameters except for the annealing parameters. We show how the model can be implemented for some special clustering problems. The T→0 limit of the Potts glass is identical to the vector quantization algorithm with certain increments. A comparative study of the Potts glass and vector quantization is also made, and it is shown that for difficult clustering problems, the Potts glass is far better than vector quantization.
ON THE EQUIVALENCE OF TWO-LAYERED PERCEPTRONS WITH BINARY NEURONS
Authors: BLATT MARCELO , DOMANY EYTAN , KANTER IDO
Published: November 2004

We consider two-layered perceptrons consisting of N binary input units, K binary hidden units and one binary output unit, in the limit N≫K≥1. We prove that the weights of a regular irreducible network are uniquely determined by its input-output map up to some obvious global symmetries. A network is regular if its K weight vectors from the input layer to the K hidden units are linearly independent. A (single layered) perceptron is said to be irreducible if its output depends on every one of its input units; and a two-layered perceptron is irreducible if the K+1 perceptrons that constitute such network are irreducible. By global symmetries we mean, for instance, permuting the labels of the hidden units. Hence, two irreducible regular two-layered perceptrons that implement the same Boolean function must have the same number of hidden units, and must be composed of equivalent perceptrons.
TRAINING NEURAL NETWORKS BY MEANS OF GENETIC ALGORITHMS WORKING ON VERY LONG CHROMOSOMES
Authors: KORNING PETER G.
Published: November 2004

In the neural network/genetic algorithm community, rather limited success in the training of neural networks by genetic algorithms has been reported. In a paper by Whitley et al. (1991), he claims that, due to “the multiple representations problem”, genetic algorithms will not effectively be able to train multilayer perceptrons, whose chromosomal representation of its weights exceeds 300 bits. In the following paper, by use of a “real-life problem”, known to be non-trivial, and by a comparison with “classic” neural net training methods, I will try to show, that the modest success of applying genetic algorithms to the training of perceptrons, is caused not so much by the “multiple representations problem” as by the fact that problem-specific knowledge available is often ignored, thus making the problem unnecessarily tough for the genetic algorithm to solve. Special success is obtained by the use of a new fitness function, which takes into account the fact that the search performed by a genetic algorithm is holistic, and not local as is usually the case when perceptrons are trained by traditional methods.
AN APPLICATION OF HAMILTONIAN NEURODYNAMICS USING PONTRYAGIN’S MAXIMUM (MINIMUM) PRINCIPLE
Authors: KOSHIZEN TAKAMASA , FULCHER JOHN
Published: November 2004

Classical optimal control methods, notably Pontryagin’s Maximum (Minimum) Principle (PMP) can be employed, together with Hamiltonians, to determine optimal system weights in Artificial Neural dynamical systems. A new learning rule based on weight equations derived using PMP is shown to be suitable for both discrete- and continuous-time systems, and moreover, can also be applied to feedback networks. Preliminary testing shows that this PMP learning rule compares favorably with Standard BackPropagation (SBP) on the XOR problem.
MULTILAYER PERCEPTRONS TO APPROXIMATE COMPLEX VALUED FUNCTIONS
Authors: ARENA P. , FORTUNA L. , RE R. , XIBILIA M.G.
Published: November 2004

In this paper the approximation capabilities of different structures of complex feedforward neural networks, reported in the literature, have been theoretically analyzed. In particular a new density theorem for Complex Multilayer Perceptrons with complex valued non-analytic sigmoidal activation functions has been proven. Such a result makes Multilayer Perceptrons with complex valued neurons universal interpolators of continuous complex valued functions. Moreover the approximation properties of superpositions of analytic activation functions have been investigated, proving that such combinations are not dense in the set of continuous complex valued functions. Several numerical examples have also been reported in order to show the advantages introduced by Complex Multilayer Perceptrons in terms of computational complexity with respect to the classical real MLP.
THEORETICAL RESULTS FOR A CLASS OF NEURAL NETWORKS
Authors: ROMANIUK STEVE G.
Published: November 2004

The ability to derive minimal network architectures for neural networks has been at the center of attention for several years now. To this date numerous algorithms have been proposed to automatically construct networks. Unfortunately, these algorithms lack a fundamental theoretical analysis of their capabilities and only empirical evaluations on a few selected benchmark problems exist. Some theoretical results have been provided for small classes of well-known benchmark problems such as parity- and encoder-functions, but these are of little value due to their restrictiveness. In this work we describe a general class of 2-layer networks with 2 hidden units capable of representing a large set of problems. The cardinality of this class grows exponentially with regard to the inputs N. Furthermore, we outline a simple algorithm that allows us to determine, if any function (problem) is a member of this class. The class considered in this paper includes the benchmark problems parity and symmetry. Finally, we expand this class to include an even larger set of functions and point out several interesting properties it exhibits.
NEW RESULTS FOR THE DYNAMICAL CRITICAL BEHAVIOR OF THE TWO-DIMENSIONAL ISING MODEL
Authors: TIGGEMANN DANIEL
Published: November 2004

Using the new supercomputer JUMP at the Research Center Jülich, we were able to simulate large lattices (up to L=2·106, a new world record) for long times (up to T=6000 for L=1.5·105). Using this data, we examined the dynamical critical exponent z. The old assumption of z=2 with logarithmic corrections seems very unlikely according to our data, leaving the asymptotic value of z≃2.167.
NONSYMMETRIC TWO-BODY SCORE FUNCTION FOR PROTEIN FOLD RECOGNITION: NEXT NEAREST NEIGHBOR-ADJACENCY OF TWO AMINO ACIDS
Authors: HEO MUYOUNG , CHEON MOOKYUNG , CHANG IKSOO
Published: November 2004

The usual two-body score (energy) function to recognize native folds of proteins is Miyazawa–Jernigan (MJ) pairwise-contact function. The pairwise-contact parameters between two amino acids in MJ function are symmetric in a sense that a directional order of amino acids sequence along the backbone of a protein is ignored in constructing score parameters. Here we report that we succeeded in constructing a nonsymmetric two-body score function, capturing a directional order of amino acids sequence, by a perceptron learning and a protein threading. We considered pairs of two adjacent amino acids that are separated by two consecutive peptide bonds with the backbone directionality from the N-terminus to the C-terminus of a protein. We also considered the local environmental character, such as the secondary structures and the hydrophobicity (solvation), of amino acids in protein structures. The score is a corresponding propensity for a directional alignment of these two adjacent amino acids with their local environments. The resulting score function simultaneously recognized native folds of 1006 proteins covering all representative proteins with a homology less than 30% among them. The quality of this score function was validated by a threading test of new distinct 382 proteins with a homology less than 90% among them, and it entailed a high success ratio for recognizing native folds of 364 (95.3%) proteins. It showed a good feasibility of designing protein score functions for protein fold recognition by a perceptron learning and a protein threading.
CALCULATING ANCESTORS IN ONE-DIMENSIONAL CELLULAR AUTOMATA
Authors: MORA JUAN CARLOS SECK TUOH , MARTÍNEZ GENARO JUÁREZ , MCINTOSH HAROLD V.
Published: November 2004

One-dimensional cellular automata are dynamical systems characterized by discreteness (in space and time), determinism and local interaction. We present a procedure to calculate the ancestors for a given sequence of states, which is based on a special kind of graph called subset diagram. We use this diagram to specify subset tables for calculating ancestors which are not Garden-of-Eden sequences, hence the process is able to yield ancestors in several generations. Some examples are illustrated using the cellular automaton Rule 110 which is the most interesting automaton of two states and three neighbors.
QUANTUM BOUND STATES FOR A DERIVATIVE NONLINEAR SCHRÖDINGER MODEL AND NUMBER THEORY
Authors: BASU-MALLICK B. , BHATTACHARYYA TANAYA , SEN DIPTIMAN
Published: November 2004

A derivative nonlinear Schrödinger model is shown to support localized N-body bound states for several ranges (called bands) of the coupling constant η. The ranges of η within each band can be completely determined using number theoretic concepts such as Farey sequences and continued fractions. For N≥3, the N-body bound states can have both positive and negative momenta. For η>0, bound states with positive momentum have positive binding energy, while states with negative momentum have negative binding energy.
CONSEQUENCES OF COVARIANCE IN KALUZA–KLEIN THEORY
Authors: WESSON PAUL S.
Published: November 2004

When the (3+1) Einstein equations with matter are regarded as a subset of the (4+1) Kaluza–Klein equations in apparent vacuum, the recovery of appropriate properties of matter requires in general that the (4+1) metric depend on all the coordinates including the extra one. We display some consequences of (4+1) covariance through the use of exact solutions and coordinate transformations. We conclude that 4-D physics can be regarded as taking place on a hypersurface in 5-D, a mathematical condition which may be set by a physical one on the rest masses of particles.
THE QUANTUM GROUP REALIZATIONS OF 3-D CHERN–SIMONS THEORIES
Authors: RAMÍREZ C. , URRUTIA L. F.
Published: November 2004

The algebra of the integrated connections and of their traces is considered in the one-genus sector of classical and quantum Chern–Simons theory. In the classical case this algebra is braid-like and although the corresponding Jacobi identities are satisfied, the associated r-matrix does not satisfy the classical Yang–Baxter equations. However, it turns out this algebra originates a "quantum" algebra SU (2)q given by its trace algebra. Canonical quantization of the above algebra is performed and a one-parameter expression for the operator ordering is considered. The same quantum algebra with a modified deformation parameter, nontrivially depending on ħ, is obtained.
TWO-PARAMETER QUANTUM-DEFORMED DUAL AMPLITUDE
Authors: JENKOVSZKY L. , KIBLER M. , MISHCHENKO A.
Published: November 2004

A four-point dual amplitude, with nonlinear trajectories, is constructed from a two-parameter deformation of the harmonic oscillator algebra. The earlier versions of the q-deformed dual models are reproduced as limiting cases of the model introduced in the present work.
RADIATIVE WEAK DECAYS OF PSEUDOSCALAR MESONS IN THE CHARM-SECTOR
Authors: BARIK N. , DASH P. C.
Published: November 2004

Radiative weak decays such as [Formula: see text] and [Formula: see text] have been investigated in a relativistic independent quark model. The branching ratios of such decays estimated in a 'static' calculation are found to be [Formula: see text], [Formula: see text].
SUPERSYMMETRY BREAKINGS AND FERMAT'S LAST THEOREM
Authors: NISHINO HITOSHI
Published: November 2004

A mechanism of supersymmetry breaking in two or four dimensions is given, in which the breaking is related to the Fermat's last theorem. It is shown that supersymmetry is exact at some irrational number points in parameter space, while it is broken at all rational number points except for the origin. Accordingly, supersymmetry is exact almost everywhere, as well as broken almost everywhere on the real axis in the parameter space at the same time. This is the first explicit mechanism of supersymmetry breaking with an arbitrarily small change of parameters around any exact supersymmetric model, which is possibly useful for realistically small nonperturbative supersymmetry breakings in superstring model building. Our superpotential can be added as a "hidden" sector to other useful supersymmetric models.
LANDAU–ZENER-LIKE TRANSITIONS OF A DRIVEN CALDIROLA–KANAI OSCILLATOR
Authors: BASKOUTAS S. , JANNUSSIS A. , MIGNANI R.
Published: November 2004

We discuss the generalized tunneling through a dynamical barrier for a damped and forced oscillator of the Caldirola–Kanai type. The Landau–Zener-like probability transition from the oscillator ground state to the nth energy level is exactly evaluated by using the Wei–Norman algebraic form of the time evolution operator. Considering a specific example, we show that an increase of the friction parameter γ implies a decrease of the occupation probability.
ESTIMATES OF THE HIGHER ORDER QCD CORRECTIONS TO R(s), Rτ AND DEEP INELASTIC SCATTERING SUM RULES
Authors: KATAEV ANDREI L. , STARSHENKO VALERY V.
Published: November 2004

We present the attempt to study the problem of the estimates of higher order perturbative corrections to physical quantities in the Euclidean region. Our considerations are based on the application of the scheme-invariant methods, namely the principle of minimal sensitivity and the effective charges approach. We emphasize that in order to obtain the concrete results for the physical quantities in the Minkowskian region the results of application of this formalism should be supplemented by the explicit calculations of the effects of the analytical continuation. We present the estimates of the order [Formula: see text] QCD corrections to the Euclidean quantities: the e+e−-annihilation D-function and the deep inelastic scattering sum rules, namely the nonpolarized and polarized Bjorken sum rules and to the Gross–Llewellyn Smith sum rule. The results for the D-function are further applied to estimate the [Formula: see text] QCD corrections to the Minkowskian quantities R(s) = σ tot (e+e− → hadrons )/σ(e+e− → µ+µ−) and [Formula: see text]. The problem of the fixation of the uncertainties due to the [Formula: see text] corrections to the considered quantities is also discussed.
SYMPLECTIC STRUCTURES FROM CENTRAL EXTENSION OF W1+∞ ALGEBRA AND KP EQUATION
Authors: GAWRYLCZYK J. , LUKIERSKI J.
Published: November 2004

We modify the first symplectic structure of KP hierarchy by considering its relation with W1+∞ algebra and introducing its central extension [Formula: see text]. We show that at least the first five Hamiltonians of modified KP hierarchy can be chosen to be conserved, in involution with respect to the symplectic bracket generated by [Formula: see text]. It appears that from the first four flows of modified KP hierarchy we shall obtain the same (2+1)-dimensional standard KP equation. We provide therefore the one-parameter family of Hamiltonians and symplectic structures describing the standard KP equation.
b → s(d)γ WITH A VECTOR-LIKE QUARK AS FOURTH GENERATION
Authors: HANDOKO L. T. , MOROZUMI T.
Published: November 2004

We study the implications of a vector-like quark, especially a down-type vector-like quark in b → s(d)γ including the neutral Higgs in the calculation. After analyzing some possible constraints for the mixing, the contribution may be significant for the b → dγ, but not for the b→sγ. We also find that the FCNC among ordinary quarks vanishes for a special form of down-type quark mass matrix.
STRINGS IN SPACE-TIME COTANGENT BUNDLE AND T-DUALITY
Authors: KLIMČÍK C. , ŠEVERA P.
Published: November 2004

A simple geometric description of T-duality is given by identifying the cotangent bundles of the original and the dual manifold. Strings propagate naturally in the cotangent bundle and the original and the dual string phase spaces are obtained by different projections. Buscher's transformation follows readily and it is literally projective. As an application of the formalism, we prove that the duality is a symplectomorphism of the string phase spaces.
DUALITIES OF LORENTZIAN AND EUCLIDEAN BLACK HOLES IN TWO-DIMENSIONAL STRING GENERATED MODELS
Authors: CADONI M. , MIGNEMI S.
Published: November 2004

We discuss the properties of Lorentzian and Euclidean black hole solutions of a generalized two-dimensional dilaton gravity action containing a modulus field, which arises from the compactification of heterotic string models. The duality symmetries of these solutions are also investigated.
ANYONS: MINIMAL AND EXTENDED FORMULATIONS
Authors: CORTÉS JOSÉ L. , PLYUSHCHAY MIKHAIL S.
Published: November 2004

The minimal (reduced) and extended canonical formulations for (2+1)-dimensional fractional spin particles are considered. We investigate the relationship between them, clearing up the meaning of the coordinates for such particles, and analyse the related question of correlation between spin and momentum. The classical Lagrangian corresponding to the extended canonical formulation is constructed, and its gauge symmetries are identified.
VALLEYS IN NONCRITICAL STRING FOAM SUPPRESS QUANTUM COHERENCE
Authors: ELLIS JOHN , MAVROMATOS N. E. , NANOPOULOS D. V.
Published: November 2004

As an example of our noncritical string approach to microscopic black hole dynamics, we exhibit some string contributions to the [Formula: see text] matrix relating in- and out-state density matrices that do not factorize as a product of S and S† matrices. They are associated with valley trajectories between topological defects on the string worldsheet, that appear as quantum fluctuations in the space-time foam. Through their uv renormalization scale dependences these valleys cause non-Hamiltonian time evolution and suppress off-diagonal entries in the density matrix at large times. Our approach is a realization of previous formulations of nonequilibrium quantum statistical mechanics with an arrow of time.
WEAK RADIATIVE DECAYS OF PSEUDOSCALAR CHARMED MESONS
Authors: MAHARANA L. , PANDA A. R. , SAHOO R. K.
Published: November 2004

We consider here radiative weak decays of charmed mesons such as [Formula: see text] and [Formula: see text] in a quark model where in general a translationally invariant SU(6) hadronic state is described by constituent quark field operators satisfying equal time algebra and a harmonic oscillator wave function. The model had its earlier success during its application to a variety of hadronic phenomena, and here also, without any free parameters, it calculates the branching ratios as [Formula: see text] and [Formula: see text]. Such calculations are very close to the estimations of Asthana and Kamal, and thus is consistent with the QCD enhancement of the latter branching ratio with respect to the former.
CHERN–SIMONS APPROACH TO THREE-MANIFOLD INVARIANTS
Authors: BRODA BOGUSŁAW
Published: November 2004

A new, formal, noncombinatorial approach to invariants of three-dimensional manifolds of Reshetikhin, Turaev and Witten in the framework of nonperturbative topological quantum Chern–Simons theory, corresponding to an arbitrary compact simple Lie group, is presented. A direct implementation of surgery instructions in the context of quantum field theory is proposed. An explicit form of the specialization of the invariant to the group SU(2) is shown.
QUANTUM PHENOMENA BETWEEN UNIFORMLY MOVING PLATES
Authors: JÁUREGUI R. , VILLARREAL C. , HACYAN S.
Published: November 2004

The quantum theory of fields with moving boundary conditions in four-dimensional space-time is studied. We consider the particular case of a scalar massless field between two infinite parallel plates moving with constant relative velocity. It is shown that this motion produces squeezed states, and creates 'particles' at the expense of the Casimir energy.