39,163 research outputs found
The Blizzard Challenge 2009
The Blizzard Challenge 2009 was the fifth annual Blizzard Challenge. As in 2008, UK English and Mandarin Chinese were the chosen languages for the 2009 Challenge. The English corpus was the same one used in 2008. The Mandarin corpus was provided by iFLYTEK. As usual, participants with limited resources or limited experience in these languages had the option of using unaligned labels that were provided for both corpora and for the test sentences. An accent-specific pronunciation dictionary was also available for the English speaker. This year, the tasks were organised in the form of âhubs â and âspokes â where each hub task involved building a general-purpose voice and each spoke task involved building a voice for a specific application. A set of test sentences was released to participants, who were given a limited time in which to synthesise them and submit the synthetic speech. An online listening test was conducted to evaluate naturalness, intelligibility, degree of similarity to the original speaker and, for one of the spoke tasks, âappropriateness.
Complex structures in galaxy cluster fields: implications for gravitational lensing mass models
The distribution of mass on galaxy cluster scales is an important test of
structure formation scenarios, providing constraints on the nature of dark
matter itself. Several techniques have been used to probe the mass
distributions of clusters, sometimes yielding results which are discrepant, or
at odds with clusters formed in simulations - for example giving NFW
concentration parameters much higher than expected in the standard CDM model.
In addition, the velocity fields of some well studied galaxy clusters reveal
the presence of several structures close to the line-of-sight, often not
dynamically bound to the cluster itself. We investigate what impact such
neighbouring but unbound massive structures would have on the determination of
cluster profiles using weak gravitational lensing. Depending on its
concentration and mass ratio to the primary halo, one secondary halo close to
the line-of-sight can cause the estimated NFW concentration parameter to be
significantly higher than that of the primary halo, and also cause the
estimated mass to be biased high. Although it is difficult to envisage how this
mechanism alone could yield concentrations as high as reported for some
clusters, multiple haloes close to the line-of-sight, such as in the case of
Abell 1689, can substantially increase the concentration parameter estimate.
Together with the fact that clusters are triaxial, and that including baryonic
physics also leads to an increase in the concentration of a dark matter halo,
the tension between observations and the standard CDM model is eased. If the
alignment with the secondary structure is imprecise, then the estimated
concentration parameter can also be even lower than that of the primary halo,
reinforcing the importance of identifying structures in cluster fields.Comment: To appear in MNRAS letters, 5 pages, 3 figure
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Understanding the impact of volunteering on pro-environmental behavioural change
This article examines whether there is an association between engaging in environmental volunteering activities and pro-environmental behavioural change. Utilising self-reported surveys, the article explores the potential impact that environmental volunteering has on people's pro-environmental behaviours over time, using The Conservation Volunteers' two volunteering programmes â Green GymsÂź and Action Teams â as a comparative case study. The findings show a positive association between environmental volunteering activities and a person's self-reported pro-environmental behaviours over time. Further, volunteers presented improved impact across almost all of the eight pro-environmental behaviours measured, with differences observed between the two volunteering programmes as well as sociodemographic groupings
Automatic continuum analysis of reflectance spectra
A continuum algorithm based on a Segmented Upper Hull method (SUH) is described. An upper hull is performed on segments of a spectrum defined by local minima and maxima. The segments making a complete spectrum are then combined. The definition of the upper hull allows the continuum to be both concave and/or convex, adapting to the shape of the spectrum. The method performs multiple passes on a spectrum by segmenting each local maximum to minimum and performing an upper hull. The algorithm naturally adapts to the widths of absorption features, so that all features are found, including the nature of doublets, triplets, etc. The algorithm is also reasonably fast on common minicomputers so that it might be applied to the large data sets from imaging spectrometers
Causes of spurious features in spectral reflectance data
Several techniques are becoming common in the analysis of imaging spectrometer data that can lead to spurious absorption features or to changes in the position, width, and shape of actual absorption features. It is a common practice to calibrate AIS or other imaging spectrometer data by averaging each pixel along the flight line. The average is used to calibrate the spectral data by dividing the spectrum at each pixel by the average. If some pixels in the data set contain an absorption, then the average will also show an absorption. Some AIS data has had problems with wavelength stability from one scan line to the next which can produce spurious features with some analysis methods. If a pixel has a spectrum with an absorption having a different position or width than the spectrum used in a ratio, then the ratio can produce a spurious absorption at a different position and width than the true absorption feature. An average spectrum ratioed to each pixel will produce band shifts, and changes in width or shape. If continuum removal is performed by substraction rather than division, band positions can also be shifted
Spectral evidence for carbonates on Mars: Hydrous carbonates
Although many of the spectral features of the Martian samples studied are not unique mineralogical indicators, much of the current spectral data is consistent with (possibly abundant) hydrous carbonates on the surface of Mars. The absorption features in the measured samples were quite weak compared with those of anhydrous carbonates. The weak features imply that significantly more hydrous carbonates can be incorporated onto the surface before becoming spectrally evident; however, exact limits have yet to be determined. The stability of these materials in the Martian environment is not known, but their formation and occurrence in low temperature terrestrial environments makes them appealing candidates for weathering products on Mars
Magnetic blackbody shift of hyperfine transitions for atomic clocks
We derive an expression for the magnetic blackbody shift of hyperfine
transitions such as the cesium primary reference transition which defines the
second. The shift is found to be a complicated function of temperature, and has
a T^2 dependence only in the high-temperature limit. We also calculate the
shift of ground-state p_1/2 hyperfine transitions which have been proposed as
new atomic clock transitions. In this case interaction with the p_3/2
fine-structure multiplet may be the dominant effect
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