Stationarity tests for spatial point processes using discrepancies.

For testing stationarity of a given spatial point pattern, Guan (2008) proposed a model-free statistic, based on the deviations between observed and expected counts of points in expanding regions within the sampling window. This article extends his method to a general class of statistics by incorporating also such information when points are projected to the axes and by allowing different ways to construct regions in which the deviations are considered. The limiting distributions of the new statistics can be expressed in terms of integrals of a Brownian sheet and hence asymptotic critical values can be approximated. A simulation study shows that the new tests are always more powerful than that of Guan. When applied to the longleaf pine data where Guan's test gave an inconclusive answer, the new tests indicate a clear rejection of the stationarity hypothesis.

Silent aspiration and swallowing physiology after radiotherapy in patients with nasopharyngeal carcinoma.

BACKGROUND: There is a paucity of knowledge on dysphagia in patients with nasopharyngeal carcinoma postradiotherapy (NPC post-RT). The purpose of this study was to establish silent aspiration occurrence, safe bolus consistency, and their relationship with swallowing physiology in patients with dysphagic NPC post-RT. METHODS: Eighty-five patients with dysphagic NPC post-RT were assessed across 4 bolus consistencies. We compared penetration-aspiration scores against 4 swallowing physiology impairments. RESULTS: Silent aspiration occurred in 65.9% of patients with dysphagia, with 64.7% on thin fluids, 35.3% on thick fluids, 11.8% on pureed diet, and 5.9% on soft diet. Multivariate analysis of variance (MANOVA) indicated pharyngeal contraction and swallowing response had significant effect on thick fluids (p = .002), thin fluids (p = .017), and soft diet (p = .031). CONCLUSION: Silent aspiration of thin fluids is a common occurrence in dysphagic NPC post-RT, with least aspiration noted on soft diet. Considering the high incidence of silent aspiration, instrumental assessment in this cohort is crucial.

The accuracy of parent and teacher reports in assessing the vocabulary knowledge of Chinese children with hearing impairment.

PURPOSE: This study aimed to investigate (a) the accuracy of adult reports in assessing the vocabulary knowledge of Cantonese-speaking children with hearing impairment (HI) and (b) the factors that are associated with the accuracy of those reports. METHOD: The first participant group consisted of 47 children and their mothers. The second group consisted of 47 children and 21 teachers. All of the children had profound HI, with a mean age of 57 months. The ratings of the adults were compared with the children's test scores in a standardized test. RESULTS: Both adult groups reported children's performance with satisfactory accuracy. Mother and teacher ratings showed fair to good agreement with each other. Two factors significantly associated with the accuracy of the report were (a) the difficulty of the vocabulary and (b) the child's vocabulary ability as determined by the standardized norm-referenced receptive vocabulary test. The mothers' education level, occupation, and socioeconomic status, and the teachers' teaching experience and length of time they had trained the child, were not significant factors. CONCLUSION: The results suggest that employing adult reports to collect data on the word knowledge of children with HI is applicable to a broad spectrum of the Cantonese-speaking Chinese population.

Characterization of shapes for use in classification of starch grains images.

As tradition Chinese herbal medicine becomes increasingly popular, there is an urgent need for efficient and accurate methods for the authentication of the Chinese Materia Medica (CMM) used in the herbal medicine. In this work, we present a denoising filter and introduce the use of chord length distribution (CLD) for the classification of starch grains in microscopic images of Chinese Materia Medica. Our simple denoising filter is adaptive to the background and is shown to be effective to remove noise, which appears in CMM microscopic starch grains images. The CLD is extracted by considering the frequency of the chord length in the binarized starch grains image, and we shall show that the CLD is an efficient and effective characterization of the starch grains. Experimental results on 240 starch grains images of 24 classes show that our method outperforms benchmark result using the current state-of-the-art method based on circular size distribution extracted by morphological operators at much higher computational cost.

Tone perception ability of Cantonese-speaking children.

Studies have shown that while children acquire all Cantonese tones by age two, they are not able to label them reliably until approximately age 10. One possible explanation for the large age discrepancy may be the different methodologies used. This study aimed to (1) investigate a new research design for the collection of reliable tone perception data from young children; (2) compare lexical and nonlexical items for testing tone perception ability; and (3) identify the relative ease of perceiving the three basic tone contrasts in Cantonese, that is, high level/high rising (T1/T2), high level/low falling (T1/T4), and, high rising/low falling tones (T2/T4). The three tone pairs were presented to 31 children in the form of word and nonword stimuli. It was found that the research design could be used to assess the tone perception knowledge of children as young as 2;09. Significant differences were found between word and nonword stimuli and also in the identification of the T2/T4 contrast in comparison with the other two pairs. Children's overall tone perception abilities are discussed in detail with reference to the role of lexical knowledge and the potential for tone perception confusions arising from differences in fundamental frequencies for tone onset and offset.