Break Indices Research Articles

Advanced Deformation Method for Breaking Waves by using CADMAS-SURF/3D

This report describes advanced deformation scheme for breaking waves, and the results of breaking wave simulation. A three-dimensional numerical wave tank was developed. This code is also adapted to the parallel computing system and multi grid size system, so that the problem is more efficiently solved. This code is called ‘CADMAS-SURF/3D’(SUper Roller Flume for Computer Aided Design of MAritime Structure in 3D). At first, the accuracy of prediction of breaking point was checked in the wave flume, and the validity was verified due to comparison of the Goda's breaking index. Then, the performance of 3 dimensional breaking problems was tried. Two types of submerged breakwater were installed in our Tank. Results were qualitatively good agreement with experiments.

Basic Characteristics of the Contact Wire Breaking by the Arc between the Contact Wire and the Pantograph

The contact wire breaking accident caused by the arc between the contact wire and the pantograph happens rarely in the DC electric railway system. The contact wire breaking phenomenon is discussed and investigated based on the experimental data performed 30 years ago. The material of the contact strip and the contact wire has changed, however, and the breaking characteristics of the contact wire caused by the arc should be different. In this paper, the contact wire breaking characteristics are carefully investigated using the recent materials. It is cleared that the breaking index of 750As is approximately appropriate in the limited condition and the other breaking condition is summarized based on the experimental data more than 400 times.

Comparison of Approaches for Predicting Break Indices in Mandarin Speech Synthesis

This study adopts a large-scale corpus with five-tier break indices annotated according to C-TOBI. Based on it, several approaches, N-gram, Markov model and decision tree learning are applied to predict break indices automatically for unrestricted mandarin text. These approaches differ mutually not only in model, but also on features and even part-of-speech tag size. A deep comparison and analysis among these approaches was made in the research.

The IBM expressive text-to-speech synthesis system for American English

Expressive text-to-speech (TTS) synthesis should contribute to the pleasantness, intelligibility, and speed of speech-based human-machine interactions which use TTS. We describe a TTS engine which can be directed, via text markup, to use a variety of expressive styles, here, questioning, contrastive emphasis, and conveying good and bad news. Differences in these styles lead us to investigate two approaches for expressive TTS, a "corpus-driven" and a "prosodic-phonology" approach. Each speaker records 11 h (excluding silences) of "neutral" sentences. In the corpus-driven approach, the speaker also records 1-h corpora in each expressive style; these segments are tagged by style for use during search, and decision trees for determining f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> contours and timing are trained separately for each of the neutral and expressive corpora. In the prosodic-phonology approach, rules translating certain expressive markup elements to tones and break indices (ToBI) are manually determined, and the ToBI elements are used in single f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0 </sub> and duration trees for all expressions. Tests show that listeners identify synthesis in particular styles ranging from 70% correctly for "conveying bad news" to 85% for "yes-no questions". Further improvements are demonstrated through the use of speaker-pooled f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and duration models

On the force-free magnetosphere of an aligned rotator

We investigate in detail the properties of the stationary force-free magnetosphere of an aligned rotator assuming the last closed field line is lying in the equatorial plane at large distances from pulsar. The pulsar equation is solved numerically using a multigrid code with high numerical resolution, and physical properties of the magnetosphere are obtained with high accuracy. We found a set of solutions with different sizes of the closed magnetic field line zone and verify the applicability of the force-free approximation. We discuss the role of electron-positron cascades in supporting the force-free magnetosphere and argue that the closed field line zone should grow with time at a slower rate than the light cylinder. This yields a pulsar breaking index of less than 3. It is shown that models of an aligned rotator magnetosphere with a widely accepted configuration of the magnetic field, such as the one considered in this paper, have serious difficulties. We discuss the solutions of this problem and argue that in any case pulsar energy losses should evolve with time differently than is predicted by the magnetodipolar formula.

Semi-empirical analysis of Sloan Digital Sky Survey galaxies - II. The bimodality of the galaxy population revisited

We revisit the bimodal distribution of the galaxy population commonly seen in the local universe. Here we address the bimodality observed in galaxy properties in terms of spectral synthesis products, such as mean stellar ages and stellar masses, derived from the application of this powerful method to a volume-limited sample, with magnitude limit cutoff M_r = -20.5, containing about 50 thousand luminous galaxies from the SDSS Data Release 2. In addition, galaxies are classified according to their emission line properties in three distinct spectral classes: star-forming galaxies, with young stellar populations; passive galaxies, dominated by old stellar populations; and, hosts of active nuclei, which comprise a mix of young and old stellar populations. We show that the extremes of the distribution of some galaxy properties, essentially galaxy colours, 4000 A break index, and mean stellar ages, are associated to star-forming galaxies at one side, and passive galaxies at another. We find that the mean light-weighted stellar age of galaxies is the direct responsible for the bimodality seen in the galaxy population. The stellar mass, in this view, has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results also give support to the existence of a 'downsizing' in galaxy formation, where massive galaxies seen nowadays have stellar populations formed at early times.

The K20 survey

The K20 survey is a near infrared-selected, deep () redshift survey targeting galaxies in two independent regions of the sky, the Chandra Deep Field South and the field around the quasar , for a total area of 52 arcmin2. The total Ks-selected sample includes 545 objects. Low-resolution () optical spectra for 525 of them have been obtained with the FORS1/FORS2 spectrographs at the ESO/VLT, providing 501 spectroscopic identifications (including 12 type-1 AGN and 45 stars); consequently, we were able to measure redshifts and identify stars in 96% of the observed objects, whereas the spectroscopic completeness with respect to the total photometrically selected sample is 92% (501/545). The K20 survey is therefore the most complete spectroscopic survey of a near infrared-selected sample to date. The K20 survey contains 444 spectroscopically identified galaxies, covering a redshift range of , with a mean redshift ; excluding the 32 “low-quality” redshifts does not significantly change these values. This paper describes the final K20 spectroscopic catalogue, along with the technique used to determine redshifts, measure the spectral features and characterize the spectra. The classification of the galaxy spectra has been performed according to a simple parametric recipe that uses the equivalent widths of the two main emission lines ([OII]λ3727 and Hα+[NII]) and two continuum indices (the 4000 Å break index, D4000, and a near-UV color index, ). We defined three main spectroscopic classes: red early-type galaxies, blue emission-line galaxies and the intermediate galaxies, which show emission lines but a red continuum. More than 95% of the examined galaxies is included in one of these spectral types and a composite spectrum is built for each of the three galaxy classes. The full spectroscopic catalogue, the reduced individual spectra and the composite spectra are released to the community through the K20 web page (http://www.arcetri.astro.it/~k20/). The blue emission-line and the early-type galaxies have been divided in redshift bins, and the corresponding composite spectra have been built, in order to investigate the evolution of the spectral properties of the K20 galaxies with redshift. The early-type average spectra are remarkable in their similarity, showing only subtle but systematic differences in the D4000 index, which are consistent with the ageing of the stellar population. Conversely, the star-forming galaxies present a significant “blueing” of the optical/near-UV continuum with redshift, although the [OII] equivalent width remains constant (~33 Å) in the same redshift intervals. We reproduce the observed properties with simple, dust-free population synthesis models, suggesting that the high-redshift galaxies are younger and more active than those detected at lower redshift, whilst the equivalent width of the emission lines apparently require a lower metallicity for the low-redshift objects. This may be consistent with the metallicity-luminosity relationship locally observed for star-forming galaxies.

Simultaneous recognition of words and prosody in the Boston University Radio Speech Corpus

This paper describes automatic speech recognition systems that satisfy two technological objectives. First, we seek to improve the automatic labeling of prosody, in order to aid future research in automatic speech understanding. Second, we seek to apply statistical speech recognition models of prosody for the purpose of reducing the word error rate of an automatic speech recognizer. The systems described in this paper are variants of a core dynamic Bayesian network model, in which the key hidden variables are the word, the prosodic tag sequence, and the prosody-dependent allophones. Statistical models of the interaction among words and prosodic tags are trained using the Boston University Radio Speech Corpus, a database annotated using the tones and break indices (ToBI) prosodic annotation system. This paper presents both theoretical and empirical results in support of the conclusion that a prosody-dependent speech recognizer—a recognizer that simultaneously computes the most-probable word labels and prosodic tags—can provide lower word recognition error rates than a standard prosody-independent speech recognizer in a multi-speaker speaker-dependent speech recognition task on radio speech.

Quasars and the Big Blue Bump

We investigate the ultraviolet-to-optical spectral energy distributions of 17 active galactic nuclei (AGNs) using quasi-simultaneous spectrophotometry spanning 900-9000 A (rest frame). We employ data from the Far Ultraviolet Spectroscopic Explorer, the Hubble Space Telescope, and the 2.1 m telescope at Kitt Peak National Observatory. Taking advantage of the short-wavelength coverage, we are able to study the so-called big blue bump, the region in which the energy output peaks, in detail. Most objects exhibit a spectral break around 1100 A. Although this result is formally associated with large uncertainty for some objects, there is strong evidence in the data that the far-ultraviolet spectral region is below the extrapolation of the near-ultraviolet-optical slope, indicating a spectral break around 1100 A. We compare the behavior of our sample to those of non-LTE thin-disk models covering a range in black hole mass, Eddington ratio, disk inclination, and other parameters. The distribution of ultraviolet-optical spectral indices redward of the break and far-ultraviolet indices shortward of the break are in rough agreement with the models. However, we do not see a correlation between the far-ultraviolet spectral index and the black hole mass, as seen in some accretion disk models. We argue that the observed spectral break is intrinsic to AGNs, although intrinsic reddening as well as Comptonization can strongly affect the far-ultraviolet spectral index. We make our data available online in digital format.

Examination of empirical formulas for wave shoaling and breaking on steep slopes

Estimation of the wave height transformation of shoaling and breaking is essential for the nearshore hydrodynamics and the design of coastal structures. Many empirical formulas have been well recognized to the wave height transformation, but most of them were only applicable for gentle slopes. This paper reports the experimental results of wave shoaling and breaking over the steep slopes to examine the applicability of the previous empirical formulas. Two steep bottom slopes of 1/3 and 1/5, and one gentle slope of 1/10 were conducted in the present experiments. Experimental results show that the shoaling distance of steep slopes become short and the surface waves may be partially reflected from the steep bottom, thus the estimation of wave shoaling using the well-known previous formula did not conform completely to the experimental results. The previous empirical formulas for the wave breaking criteria were also examined, and the modified equations to the steep beaches were proposed in this work. A numerical model was finally adopted to calculate the wave height transformation in the surf zone by introducing the modified breaking index.

Analyses of impact of metal ion contamination on carp (Cyprinus carpio L.) gill cell suspensions.

The decline in fish population because of water contamination is problem. As a result of direct exposure in water, it has been readily accepted that the gills are the main site of water contamination and toxicity (e.g., metal ions). In the present study, we investigated metal ion contamination on the functional capacity of carp gill cells with antioxidant interactions in an in vitro study. The extent of cellular membrane damage, lipid peroxidation (LPO) (as TBARS levels), and glutathione (GSH) content were investigated after the addition of two metal ion compounds (viz., CuSO(4) and HgCl(2)) in various concentrations (300, 500, 700, 1000, and 3000 microM) to gill cell preparation of the freshwater fish carp (Cyprinus carpio L.) with modulations by bovine serum albumin (BSA) (0.5% and 1.0%) and dimethyl sulfoxide (DMSO) (0.5%) as free-radical scavengers. The Comet assay technique was also performed for the highest concentrations of the two mentioned metal ions as an index of DNA breaks. The outcomes were as follows: (1) Copper and mercury increased the rate of LPO dose dependently (r=+0.995 and r=+0.993, respectively; p<0.001), but the GSH content was only marginally affected (r = -0.787 and r = -0.844, respectively; p <0.05). (2) Depletion of GSH molecules by copper had a wider range than mercury. (3) In the highest concentration of metal ions (3000 microM), both DMSO and 1.0% BSA showed a pro-oxidative potential to elevate the levels of TBARS (p<0.001), but for other concentrations when supplemented with three scavengers, a fall in the levels of the latter was found. (4) The addition of 1.0% BSA to medium containing 3000 microM of metal ions caused a significant decline in GSH content (p<0.01). (5) Copper and mercury could cause a high rate of DNA breaks (single stranded) in carp gill cell suspensions as a Comet appearance. These findings indicate that copper and mercury have a deleterious influence on membrane integrity and GSH content in a relatively dose-dependent manner. The complexes of metal ions and thiol (SH) residues of cell proteins could also act as a potential cell toxicant leading to disturbances in cell functions causing cell death. DNA fragmentation is frequent in metal ion contamination.

A set of corpus-based text-to-speech synthesis technologies for Mandarin Chinese

This paper presents a set of corpus-based text-to-speech synthesis technologies for Mandarin Chinese. A large speech corpus produced by a single speaker is used, and the speech output is. synthesized from waveform units of variable lengths, with desired linguistic properties, retrieved from this corpus. Detailed methodologies were developed for designing phonetically rich and prosodically rich corpora by automatically selecting sentences from a large text corpus to include as many desired phonetic combinations and prosodic features as possible. Automatic phonetic labeling with iterative correction rules and automatic prosodic labeling with a multi-pass top-down procedure were also developed such that the labeling process for the corpora can be completely automatic. A hierarchical prosodic structure for an arbitrary desired text sentence is then generated based on the identification of different levels of break indices, and the prosodic feature sets and appropriate waveform units are finally selected and retrieved from the corpus, modified if necessary, and concatenated to produce the output speech. The special structure of Mandarin Chinese has been carefully considered in all these technologies, and preliminary assessments indicated very encouraging synthesized speech quality.

Automatic corpus-based tone and break-index prediction using K-ToBI representation

In this article we present a prosody generation architecture based on K-ToBI (Korean Tone and Break Index) representation. ToBI is a multitier representation system based on linguistic knowledge that transcribes events in an utterance. The TTS (Text-To-Speech) system, which adopts ToBI as an intermediate representation, is known to exhibit higher flexibility, modularity, and domain/task portability compared to the direct prosody generation TTS systems. However, for practical-level performance, the cost of corpus preparation is very expensive because the ToBI labeled corpus is constructed manually by many prosody experts, and normally requires large amounts of data for statistical prosody modeling. Unlike previous ToBI-based systems, this article proposes a new method, which transcribes the K-ToBI labels in Korean speech completely automatically. We develop automatic corpus-based K-ToBI labeling tools and prediction methods based on several lexico-syntactic linguistic features for decision-tree induction. We demonstrate the performance of F0 generation from automatically predicted K-ToBI labels, and confirm that the performance is reasonably comparable to state-of-the-art direct prosody generation methods and previous ToBI-based methods.

ASCA observations of the Crab-like pulsar/nebula system PSR B0540-69

The ASCA satellite has observed the 50-ms pulsar PSR B0540–69 and its associated supernova remnant SNR 0540–693 in the Large Magellanic Cloud 15 times in total, at least once a year, between 1993 June and 1999 November, including six observations with the pulsar as the main target. In all the observations, a point-like X-ray source was clearly detected at the position of PSR B0540–69 and the X-ray pulsations were detected at large significance. Folded light curves are identical throughout the observations, showing one broad pulse with a small notch at the top. Pulse frequency history during the 6.4 yr of the ASCA observations is well characterized by a second-order polynomial with a breaking index of 2.10±0.05, assuming no glitches occurred during the period. The frequency history smoothly follows the Ginga and ROSAT results and connects to the RXTE results without a measurable discontinuity. The X-ray spectrum of the whole source is well represented by a single power-law model of photon index, α=2.00±0.02, and a small photoelectric absorption, NH=(4.3±0.2)×1021 cm-2. The X-ray spectrum can also be represented by a pulsed power-law spectrum with photon index of 1.80±0.05 with 24 per cent in amplitude at 1 keV, embedded in a constant power-law component with photon index of 2.17±0.02 ascribed to a nebular component. Spectral properties of the X-ray emission from the pulsar and the nebula remain unchanged over the six years and are quite similar to those of the Crab pulsar and nebula.

Investigations of paper aging: a search for archive paper

The change of mechanical (folding endurance index, breaking stress, breaking length, breaking index, tear index ), optical (brightness), chemical (cold extract pH, alkali reserve) and physical (water absorbency by surface, smoothness) characteristics of 5 paper samples were measured during the accelerated aging at 105 ± 2°C, and the measured exponential dependencies were described and fitted by the formal first-order kinetics. The statistic parameters of such fitting calculations evidenced good agreement of the experimental and calculated data. The relative decrease of each paper property corresponding to 48 days of accelerated aging was evaluated in order to compare the durability of paper samples. The best aging resistance was obtained for paper MAESTRO® Classic (SCP Ružomberok, Slovak Republic) and this paper material may be recommended for archival applications.

COMPUTATION OF RANDOM WAVE TRANSFORMATIONS IN 3-D BATHYMETRY USING GRADATIONAL BREAKER INDEX

A new system of gradational breaker index is introduced to facilitate the computation of random wave transformations in shallow water. The parabolic equation is used to compute wave shoaling, refraction, and diffraction. Computation is made with multiple levels of wave heights under the Rayleigh distribution. Wave breaking is assumed to occur when the ratio of wave height to local water depth exceeds the breaking index, which takes the largest value for largest wave height level and gradually decreases as the wave height level goes down.The new system succeeds in reproducing the random wave breaking diagrams by Goda (1975), and shows good agreements with various experimental results on wave transformations over bar and trough topographies, elliptical shoals, and artificial reef systems.

Stellar populations in the nuclear regions of nearby radio galaxies

ABSTRACT We present optical spectra of the nuclei of seven luminous (P 178MHz >∼10 25 W Hz −1 Sr ) nearby (z < 0.08) radiogalaxies, which mostly correspond tothe FR II class. In two cases, Hydra A and 3C 285, the Balmer and λ4000˚A breakindices constrain the spectral types and luminosity classes of the stars involved, re-vealing that the blue spectra are dominated by blue supergiant and/or giant stars.The ages derived for the last burst of star formation in Hydra A are between 7 and40 Myr, and in 3C 285 about 10 Myr. The rest of the narrow-line radiogalaxies (four)have λ4000˚A break and metallic indices consistent with those of ellipt ical galaxies.The only broad-line radiogalaxy in our sample, 3C 382, has a strong featureless bluecontinuum and broad emission lines that dilute the underlying blue stellar spectra.We are able to detect the Ca II triplet in absorption in the seven objects, with goodquality data for only four of them. The strengths of the absorptions are similar tothose found in normal elliptical galaxies, but these values are both consistent withsingle stellar populations of ages as derived from the Balmer absorption and breakstrengths, and, also, with mixed young+old populations.Key words: galaxies: active – galaxies: starbursts – galaxies: stellar content

Spectral analysis of the Stromlo-APM Survey -- I. Spectral properties of galaxies

We analyse spectral properties of 1671 galaxies from the Stromlo—APM Survey, selected to have 15 ≤ bJ ≤ 17.15 and having a mean redshift z = 0.05. This is a representative local sample of field galaxies, so the global properties of the galaxy population provide a comparative point for analysis of more distant surveys. We measure Hα, [O ii] λ3727, [S ii] λλ6716, 6731, [N ii] λ6583 and [O i] λ6300 equivalent widths and the D4000 break index. The 5-Å-resolution spectra use an 8-arcsec slit, which typically covers 40-50 per cent of the galaxy area. We find no evidence for systematic trends depending on the fraction of galaxy covered by the slit, and further analysis suggests that our spectra are representative of integrated galaxy spectra. We classify spectra according to their Hα emission, which is closely related to massive star formation. Overall we find that 61 per cent of galaxies are Hα emitters with rest-frame equivalent widths EW(Hα) ≳2 Å. The emission-line galaxy (ELG) fraction is smaller than seen in the Canada—France Redshift Survey (CFRS) at z = 0.2, and is consistent with a rapid evolution of Hα luminosity density. The ELG fraction and EW(Hα) increase at fainter absolute magnitudes, smaller projected area and smaller D4000. In the local Universe, faint, small galaxies are dominated by star formation activity, while bright, large galaxies are more quiescent. This picture of the local Universe is quite different from that of the distant one; bright galaxies appear to show rapidly increasing activity as one moves further back in time. We find that the ratio [N ii] λ6583/Hα is anticorrelated with EW(Hα), and that the value of 0.5 commonly used to remove the [N ii] contribution from blended Hα+[N ii] λλ6548, 6583 applies only for samples with an EW distribution similar to that seen at low redshift. We show that the [O ii], [N ii], [S ii] and Hα EWs are correlated, but with large dispersions (∼50 per cent) owing to the diversity of galaxy contents sampled. Our [O ii]-Hα relation is similar to the one derived by Kennicutt, but is 10 per cent higher at 1σ significance. We show that this relation is not valid for distant, strong [O ii] emitters with blue colours, which are more numerous than locally. This relation would overestimate the individual star formation rate by ∼50 per cent for these kinds of galaxies. We find that, on average, luminous blue ELGs are likely to be enhanced in nitrogen abundance. This suggests that in faint, low-mass, late-type ELGs nitrogen is a primary element, whereas in brighter, more massive galaxies nitrogen comes from a secondary source. We also find that 4 per cent of early-type galaxies show star formation activity; this fraction seems to increase at higher redshifts.

Dexamethasone ameliorates oxidative DNA damage induced by benzene and LPS in mouse bone marrow

Mice were grouped to receive vehicle, dexamethasone (DEX), lipopolysaccharide (LPS), benzene (BZ, 200 mg/kg) and combinations: LPS + DEX, BZ + DEX, LPS + BZ, LPS + DEX + BZ. The DNA damage in bone marrow cells from BZ group was enhanced 2.8-fold measured by nuclear 8-hydroxy-2′-deoxyguanosine(8-oxodG) and 1.4-fold measured by Comet score (index of DNA breaks) (p<0.05). In the BZ + DEX group, 8-oxodG level and the Comet score were lowered to 65% and 76% respectively of that in the BZ group (p<0.05). The BZ + LPS caused a 3.9-fold increase in 8-oxodG and a 1.6-fold increase in the Comet score (p<0.05). The LPS + DEX + BZ lowered 8-oxodG level and the Comet score to 50% and 78% of the values in the LPS + BZ group, respectively (p<0.05). Nitrate/nitrite levels in serum were higher after BZ + LPS treatment than after all other treatments. Both 8-oxodG level and the Comet scores were correlated to the serum nitrate/nitrite level across all the treatments (r=0.55, p<0.01 and r=0.69, p<0.01, respectively). In bone marrow cells the 8-oxodG correlated with the Comet scores (r=0.80, p<0.01). We conclude that DEX administration can reduce the DNA damage from BZ treatment and from the combination of BZ and LPS. The correlation of DNA damage with nitrate/nitrite indicates the possible involvement of reactive nitrogen species (RNS) in the interaction between BZ and the inflammatory reaction stimulated by LPS. The 8-oxodG determination is more sensitive than strand break analysis by the Comet assay in bone marrow in vivo in mice for measuring the BZ-induced DNA damage.

BeppoSAX observations of isolated pulsars

Two isolated pulsars, the Crab and PSR B0540-69, were observed during the Science Verification Phase with the NFIs on board BeppoSAX. Here we present results from these two observations. In particular, we determine the spectral variations of the phase component P2, P1 and Ip of the Crab light curve using the P1/P2 and Ip/P2 ratio. We also give a brief summary of the spectral and temporal analysis. Moreover, we present the light curve of PSR B0540-69 in different energy bands and, using the best period derived from the BeppoSAX observation together with the previous ones, determine the rotational parameters of the pulsar and the relative breaking index.