Well-Being Profiles of Pre-service Teachers in Hong Kong: Associations with Teachers' Self-Efficacy During the COVID-19 Pandemic

The present study aims to (1) identify the profiles of subjective well-being (SWB) and psychological well-being (PWB) in a sample of pre-service teachers during the second wave of the COVID-19 pandemic in Hong Kong, and (2) explore how different profiles are linked with teachers' self-efficacy. Participants were 291 pre-service teachers (Mage = 21.295, SD = 2.812, female = 89.903%) who were invited to complete self-report measures of SWB, PWB, and teachers' self-efficacy. Latent profile analysis with maximum likelihood estimation was conducted to identify well-being profiles that emerged in this sample. The results suggested a 3-class model with a high, moderate, and low well-being group. The findings also revealed that the pre-service teachers' well-being profiles as reflected by SWB and PWB indicators were consistent. Moreover, the pre-service teachers in the higher well-being group reported higher teaching self-efficacy than those in the lower well-being group. Findings highlighted the benefits of supporting pre-service teachers' well-being (i.e., SWB and PWB) to maintain their teachers' self-efficacy during the COVID-19 pandemic when teacher education and practicum are significantly disrupted. Interventions targeting various positive psychological skills (e.g., mindfulness, self-compassion, and positive reappraisal) are warranted. Future investigation is needed to examine the longitudinal relationship between pre-service teachers' well-being and self-efficacy.

The effectiveness of a positive psychological intervention for promoting preschool teachers' well-being and professional competence: EASP intervention program

The present study investigated the effectiveness of the Early Advancement in Social-Emotional Health and Positivity (EASP) program, a positive psychological intervention promoting preschool teachers' well-being and the motivational aspect of professional competence. Participants were 273 in-service preschool teachers (Mage = 34.56 years, SD = 9.52, range = 22-58; female = 98.90%) who participated in a 2-month randomized controlled trial. Participants were randomly assigned to the intervention group (n = 143) receiving 1) four online workshops, 2) a smartphone app, and 3) an online activity, or to the wait-list control group (n = 130), which received the intervention materials after all the data collection. Participants reported their well-being dimensions, teaching self-efficacy, and autonomous motivation for teaching before and after the intervention. Results from a path analytic model exhibited excellent fit with the data, χ2 = 37.62, df = 33, CFI = .99, TLI = .98, RMSEA = .02 [90% CI = 0.00, 0.05], SRMR = .02. The intervention had direct effects on changes in well-being dimensions, including positivity, outcome, strength, engagement, and resilience (β = .14 to .26, ps = .00 to .04), and indirect intervention effects on changes in teaching self-efficacy and autonomous motivation for teaching (β = .14 to .15, ps = .00 to .01). These findings highlighted the potential value of implementing positive psychological interventions in educational settings to promote the well-being and professional competence among preschool teachers.

Can a multicomponent positive psychological intervention promote well-being in parents of young children? A randomized controlled trial study in Hong Kong

The present research examined the effects of an Early Advancement in Social-Emotional Health and Positivity (EASP) multicomponent positive psychological intervention on parents' well-being in Hong Kong. Participants were parents of young children (N = 120; Mage  = 37.19 years, SD = 4.71, range = 24-53; female = 95.00%) who participated in the one-month randomized control trial. Participants were randomly assigned into the intervention (n = 50) and waitlist control groups (n = 70). Parents in the intervention group received two online workshops and an evidence-based smartphone application that targeted four positive psychological skills: (1) mindful parenting, (2) hope, (3) positive reappraisal, and (4) growth mindset. The results of the multivariate regression analysis revealed that the intervention significantly improved various dimensions of participants' positive psychological skills, subjective well-being, and psychological well-being immediately at the conclusion of the program. The findings of this study underscore the importance of the well-being payoffs linked to cultivating positive psychological skills among parents of young children.

Liver X receptor alpha ensures blood-brain barrier function by suppressing SNAI2

In Alzheimer's disease (AD) more than 50% of the patients are affected by capillary cerebral amyloid-angiopathy (capCAA), which is characterized by localized hypoxia, neuro-inflammation and loss of blood-brain barrier (BBB) function. Moreover, AD patients with or without capCAA display increased vessel number, indicating a reactivation of the angiogenic program. The molecular mechanism(s) responsible for BBB dysfunction and angiogenesis in capCAA is still unclear, preventing a full understanding of disease pathophysiology. The Liver X receptor (LXR) family, consisting of LXRα and LXRβ, was reported to inhibit angiogenesis and particularly LXRα was shown to secure BBB stability, suggesting a major role in vascular function. In this study, we unravel the regulatory mechanism exerted by LXRα to preserve BBB integrity in human brain endothelial cells (BECs) and investigate its role during pathological conditions. We report that LXRα ensures BECs identity via constitutive inhibition of the transcription factor SNAI2. Accordingly, deletion of brain endothelial LXRα is associated with impaired DLL4-NOTCH signalling, a critical signalling pathway involved in vessel sprouting. A similar response was observed when BECs were exposed to hypoxia, with concomitant LXRα decrease and SNAI2 increase. In support of our cell-based observations, we report a general increase in vascular SNAI2 in the occipital cortex of AD patients with and without capCAA. Importantly, SNAI2 strongly associated with vascular amyloid-beta deposition and angiopoietin-like 4, a marker for hypoxia. In hypoxic capCAA vessels, the expression of LXRα may decrease leading to an increased expression of SNAI2, and consequently BECs de-differentiation and sprouting. Our findings indicate that LXRα is essential for BECs identity, thereby securing BBB stability and preventing aberrant angiogenesis. These results uncover a novel molecular pathway essential for BBB identity and vascular homeostasis providing new insights on the vascular pathology affecting AD patients.

Longitudinal association between children's mastery motivation and cognitive school readiness: Executive functioning and social-emotional competence as potential mediators

This study investigated the direct relationships between kindergarten children's object and social mastery motivation and future cognitive school readiness and the indirect relationships mediated through executive functioning and social-emotional competence in the school context. The participants were 103 Hong Kong kindergarten children (45.6% girls; mean age = 60.4 months) and their teachers. The teachers reported the children's demographic information and object and social mastery motivation at Time 1 (in the middle of the school year). They rated the children's executive functioning, social-emotional competence and cognitive school readiness at Time 2 (at the end of the school year). The results from the path analysis model revealed that the children's object mastery motivation at Time 1, but not their social mastery motivation, directly predicted their cognitive school readiness at Time 2. The indirect relationships between (a) object mastery motivation at Time 1 and cognitive school readiness at Time 2 mediated through executive functioning (indirect effect: β =.32, SE =.05, p <.001) and (b) social mastery motivation at Time 1 and cognitive school readiness at Time 2 mediated through social-emotional competence (indirect effect: β =.09, SE =.03, p <.01) were significant. The findings highlight the differential roles of object and social mastery motivation in predicting children's cognitive school readiness and propose children's executive functioning and social-emotional competence as processes mediating the relationships. The results also suggest the desirability of providing kindergarten children with extensive play opportunities and materials to support their mastery motivation and cognitive school readiness.

Prospering in the midst of the COVID-19 pandemic: The effects of PROSPER-based intervention on psychological outcomes among preschool teachers

The growing concerns regarding the risks of transmitting the COVID-19 virus have intensified the job-related stressors commonly encountered by teachers in various cultural contexts. Evidence shows how the COVID-19 crisis has negatively impacted teachers' mental health outcomes such as stress, depression, and quality of life, which highlights the significance of designing psychological programs to boost teachers' well-being. This study examined the effects of a well-being intervention based on the Positivity, Relationship, Outcomes, Strength, Purpose, Engagement, and Resilience (PROSPER) framework on well-being outcomes among 76 in-service teachers (M_age = 26.05 years, SD = 4.71, range = 20–45; female = 93.4%) in Hong Kong. Participants completed survey measures associated with the seven PROSPER outcomes at baseline and 2-month follow-up. Multivariate regression analysis indicated that there were statistically significant multivariate effects for intervention conditions, Wilks' Lambda F(7, 58) = 4.50, p = .01. Results demonstrated that teachers who were assigned to the intervention condition (n = 36) had significantly higher scores than those in the control condition (n = 40) on positivity (b = 0.41, 95% CI [0.16, 0.65], p = .01), strength (b = 0.62, 95% CI [0.23, 1.01], p = .01), purpose (b = 0.61, 95% CI [0.18, 1.04], p = .01), and resilience (b = 0.57, 95% CI [0.07, 1.07], p = .04). Our findings provide evidence on the mental health benefits of the PROSPER-based psychological intervention program for preschool teachers.

Parental self-efficacy: Examining its mediating and reciprocally predictive roles in supportive emotion socialization

This longitudinal study examined the associations between child negative affect, parental self-efficacy (PSE), and parents' approaches to the provision of supportive socialization. It also investigated the bidirectionality between PSE, problem-focus socialization, and emotion-focus socialization across two time points separated by one year. Participants were 757 Hong Kong Chinese parents (47.4% fathers) of kindergarten children. At both time 1 and time 2, parents reported their PSE, problem-focus socialization, and emotion-focus socialization. Additionally, parents rated their child's negative affect at time 1. Results from the cross-lagged panel model revealed that, controlling for the effects of school's socioeconomic strata, child gender, parental age, and educational level, PSE at time 1 mediated the indirect links of child negative affect at time 1 with problem-focus (indirect effect: β = -.02, SE = .02, p < .05) and emotion-focus (indirect effect: β = -.02, SE = .01, p < .05) socialization at time 2 and that PSE (β = .10, SE = .06, p < .01) and problem-focus socialization (β = .15, SE = .03, p < .05) were reciprocally associated with each other. Findings underscored the role of PSE in understanding parental provision of supportive socialization and the co-development of belief about parenting and parenting behaviors.

Mathematics, executive functioning, and visual-spatial skills in Chinese kindergarten children: Examining the bidirectionality

This study examined the bidirectional relationships among Chinese children's mathematics, executive functioning, and visual-spatial skills during their transition from kindergarten to primary school. Participants were 172 Cantonese-speaking Hong Kong children (mean age at Time 1 = 62.75 months; 88 male) and their parents. At Time 1 (kindergarten K3), children were administered the measures of mathematics (calculation and applied problems), executive functioning (working memory and inhibitory control), and visual-spatial skills. They were reassessed on these measures at Time 2 (primary 1) 1 year later. Results from the cross-lagged panel model showed that, controlling for child age, gender, and family socioeconomic status, children's visual-spatial skills at Time 1 were significantly predictive of their mathematics at Time 2 and children's executive functioning and visual-spatial skills reciprocally predicted each other across times. However, children's mathematics at Time 1 were not predictive of their executive functioning or visual-spatial skills at Time 2. The findings highlight the desirability of improving children's executive functioning and visual-spatial skills to promote their mathematical performance during the formal school transition.

A simple method for detection of imprinting effects based on case-parents trios

Using data from families in which marker genotypes are known for the father, the mother and the affected offspring, a simple statistic for testing for imprinting effects is developed. The statistic considers whether the expected number of families in which the father carries more copies of a particular marker allele than the mother is equal to the expected number of families in which the mother carries more copies of the allele than the father. The proposed parent-of-origin effects test statistic (POET) is shown to be normally distributed and can be employed to test for imprinting in situations where the marker locus need not be a disease susceptibility locus and where the female and male recombination fractions are sex-specific. A simulation study is conducted to characterize the power of the POET and other properties, and its results show that it is appropriate to employ the POET.

Alcohol metabolism of local Chinese in Hong Kong: a statistical determination on the effects of various physiological factors

A study was designed to examine the elimination rate of alcohol from the body of the local Chinese after consumption of different types of alcoholic drinks. The breath alcohol of 184 healthy volunteers was determined and converted into blood alcohol levels after they finished drinking. Information on the type and volume of alcoholic drinks consumed, age group, sex, drinking habit, and drinking on empty stomach or with/after meal was recorded for each participant. The results show that the elimination rate of an individual can be explained in terms of physiological variables including sex and drinking habit. The determined elimination rates allow forensic toxicologists to back calculate the blood alcohol concentration (BAC) of the drivers at the time of accident in drunk driving cases. The elimination rates of blood alcohol at 95% prediction intervals for male and female are in the range of 9.5-23.8 mg/100 ml/h and 11.1-37.1 mg/100 ml/h, respectively.

Influence curves for factor loadings

Influence curves for the initial and rotated loadings are derived for the maximum likelihood factor analysis (MLFA) model. Cook's distances based on the empirical influence curves of factor loadings are proposed for the identification of influential observations. The distances are shown to be invariant under scale transformation and factor rotation. We find that an observation with a very large Cook's distance based on the sample influence curve may not necessarily exert an excessive influence on the factor loadings pattern but may change the ordering of the factors. The issue of the switching of factors is also studied by means of the empirical influence curve and factor scores.

Population data for the Identifier™ 15 STR loci in Hong Kong Chinese

Allele frequencies for 15 STR loci, namely D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA, which are tested for by PE Applied Biosystem's Identifier kit, were obtained from a sample of 325 unrelated Chinese in Hong Kong.

Widmark factors for local Chinese in Hong Kong

The Widmark formula has been widely adopted in forensic applications to drink driving cases for the last 70 years. It is known that the amount of alcohol consumed and the body weight of the drinkers are important information for the estimation of blood alcohol concentration (BAC). However, the direct application of the Widmark factors derived from Caucasian to the calculation of BAC for the Chinese population often encounters serious challenges. Owing to this inherent weakness, a thorough analysis to determine the theoretical Widmark factors for the Chinese population, r(0) at the start of drinking and the practical factors, r(peak), at peak BAC was conducted. In the present study, other factors such as gender, stomach condition and other physiological conditions are taken into account. The determined theoretical Widmark factors, r(0,) for local Chinese male and female are 0.68 and 0.59 (with BAC in the units of weight/volume), respectively, demonstrating the applicability of the Widmark formula to the Chinese population. The practical factors at peak BAC, r(peak), were also determined to serve the forensic purpose of refuting the "hip-flask" defence in drink driving cases. Findings show that gender and stomach condition are the key factors that could statistically explain the variability of both r(0) and r(peak).

Allele frequencies for nine STR loci in Beijing Chinese

Allele frequencies for nine STR loci namely, D3S1358, HUMvWA, HUMFIBRA/FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 were obtained from a sample of 198 unrelated Chinese in Beijing, China.

The evaluation of mixed stains from different ethnic origins: general result and common cases

In some situations, it can be inferred from the crime circumstances that the mixed stain donors are of different ethnic groups. The evaluation of DNA mixtures with contributors coming from more than one ethnic group is considered under the assumption of independence of alleles within and between ethnic groups. A general formula is derived for the assessment of the weight of evidence in mixed stain problems. This formula is equivalent to that of Fukshansky and Bär, but we give a different derivation. For the convenience of practitioners, the explicit expressions of the likelihood ratios for 14 common cases are presented. The effect of different ethnic groups to the assessment of the evidence is shown in the well-known Simpson case.

Syntheses, photophysics, and photochemistry of trinuclear copper(I) thiolate and hexanuclear copper(I) selenolate complexes: X-ray crystal structures of [Cu(6)(mu-dppm)4(mu(3)-SePh)4](BF(4))2 and [Cu(6)(mu-(Ph(2)P)(2)NH(4))(mu(3)-SePh)4](BF(4)2

A series of trinuclear copper(I) thiolate complexes, [Cu(3)(mu-dppm)(3)(mu(3)-SR)(2)]BF(4) (R = C(6)H(4)Cl-4, C(6)H(4)CH(3)-4, C(6)H(4)OCH(3)-4, C(6)H(4)(OCH(3))(2)-3,4, C(6)H(4)-benzo-15-crown-5, or (t)()Bu), [Cu(3)(mu-dppm)(3)(mu(3)-S(t)()Bu)](BF(4))(2), and [Cu(3)(mu-dppm)(3)(mu(3)-SR)(mu(3)-Cl)]BF(4) (R = C(6)H(4)CH(3)-4, C(6)H(4)(t)()Bu-4, or C(6)H(4)(CH(3))(3)-2,4,6) and two hexanuclear copper(I) selenolate complexes, [Cu(6)(mu-P(wedge)P)(4)(mu(3)-SePh)(4)](BF(4))(2) (P(wedge)P = dppm, (Ph(2)P)(2)NH), have been synthesized, and their photophysical properties have been studied. The X-ray crystal structures of both copper(I) selenolate complexes have been determined. These complexes have been shown to exhibit long-lived low-energy emission in solution, attributed to an excited state of predominantly ligand-to-metal charge-transfer [chalcogenolate to copper(I)] origin.

Porphyria cutanea tarda and melioidosis

Porphyria cutanea tarda is a metabolic disorder in the haem biosynthetic pathway. It includes a heterogeneous group of conditions, which may be inherited or, more commonly, acquired. Although porphyria cutanea tarda presents with cutaneous lesions only, it is often associated with systemic disease. A 64-year-old Chinese patient, who developed sporadic porphyria cutanea tarda 1 year after the diagnosis of pulmonary melioidosis, is discussed. The patient presented with a history of recurrent photosensitive vesicles, blisters, and skin fragility on the sun-exposed areas of both forearms and hands, 6 months after commencing doxycycline and amoxycillin. Both the histological and biochemical findings were characteristic of porphyria cutanea tarda. All the lesions subsided after cessation of these antibiotics. The patient was free of further lesions at follow-up 6 months later. The association seen in this case between porphyria cutanea tarda and melioidosis is unlikely to be coincidental, because these two diseases are both very rare in Hong Kong. In addition, the temporal relationship between the antibiotic therapy and the clinical course of skin lesions in this patient suggests that the drugs were a trigger factor, precipitating their appearance.

Population data for 12 STR loci in Hong Kong Chinese

The allele distributions at the 12 short tandem repeat (STR) loci D3S1358, HUMvWA, HUMFIBRA/FGA, HUMTHO1, HUMTPOX, HUMCSF1P0, D5S818, D13S317, D7S820, D8S1179, D21S11 and D18S51 have been determined for 284 unrelated Chinese in Hong Kong. The combined probability of identity for the 12 STR loci was about 4.1 x 10(-14) and the overall probability of excluding paternity 0.999978. None of the 12 loci were found to deviate from Hardy-Weinberg expectations according to the results of the exact test. There was also little evidence for association of alleles between loci. The results demonstrate that the loci are useful for forensic human identification and parentage testing for the Chinese population in Hong Kong.

Genetic polymorphism at three STR loci--CSF1PO, HUMTHO1 and TPOX, and the AMP-FLP locus D1S80 for the Chinese population in Hong Kong

Allele frequencies for three STR loci, namely, CSF1PO, HUMTHO1 and TPOX, and the AMP-FLP locus D1S80 were obtained from a sample of 351 unrelated Chinese in Hong Kong.

Prevalence of skin disease among school children and adolescents in a Student Health Service Center in Hong Kong

We document the prevalence and the pattern of dermatologic diseases among primary and secondary school students visiting a Student Health Service Center in Hong Kong. In this study, the differences in prevalence of skin diseases between these two groups are pointed out. A total of 1006 students from both primary (n = 559) and secondary schools (n = 447) were seen in a regional, population-based screening center during the period from October 1996 to September 1997. Each student was asked to answer a simple questionnaire to identify any skin problems and to explore health-seeking behavior. Students were then examined for evidence of skin disease. A total of 314 students (31.3%) had one or more skin disorders, the most common of which were acne vulgaris (9.9%), eczema (6.8%), café au lait spots (4.4%), congenital melanocytic nevus (3.6%), superficial fungal infections (2.2%), keratosis pilaris (1.3%), and pityriasis alba (1.0%), which represented 93% of the skin disorders encountered. Acne vulgaris and tinea cruris were distinctly more common in secondary school students, while atopic eczema and congenital melanocytic nevi were more commonly found in primary school students. Among the 314 students with skin disease, 129 (41%) had symptoms while 185 (59%) did not. Ninety of the 129 students (70%) with symptomatic skin problems did not seek medical attention. The two predominant skin diseases, acne vulgaris and endogenous eczema, both chronic skin problems, incur not only morbidity in affected individuals and families, but also use considerable resources in the community. The lack of medical intervention reported by symptomatic students in this study was unexpectedly high. Therefore it is useful to monitor the epidemiology of skin problems in children so that relevant skin health education programs and preventive measures can be planned and implemented effectively.

An in vivo trial comparing the use of different types of 532 nm Nd:YAG lasers in the treatment of facial lentigines in Oriental patients

BACKGROUND

Versapulse is a system that consists of four laser modalities and was developed with the aim of increasing cost-effectiveness. However, as these lasers share a common power supply, for the Q-switched (QS) Nd:YAG 532 nm laser a large spot diameter is necessary to lower the fluence to a suitable level. This can increase the risk of hyperpigmentation when used for the treatment of lentigines in dark-skinned patients.

OBJECTIVE

The aim of our study was to access the clinical efficacy and the complication rate of the Versapulse QS Nd:YAG 532 nm laser, the Versapulse long-pulsed Nd:YAG 532 nm laser (without the chill tip), and a conventional QS Nd:YAG 532 nm laser in the treatment of lentigines in Chinese patients.

METHODS

Thirty-four Chinese patients with lentigines were randomized to receive laser surgery, with one side of the face treated by one laser and the other side treated by a different system. Patients were monitored for 6 weeks to assess the degree of clearing, hyperpigmentation, hypopigmentation, and erythema. Assessments involved patients interviewed using a visual analog questionnaire and two blinded observers who evaluated the pre- and posttreatment clinical photographs.

RESULTS

The Versapulse QS Nd:YAG 532 nm laser was associated with a statistically higher risk of complications. The Versapulse long-pulsed Nd:YAG 532 nm laser was compatible with the conventional QS Nd:YAG 532 nm laser in terms of clinical efficacy and complication rates.

CONCLUSION

The Versapulse long-pulsed 532 nm laser is more effective and should be used instead of the Versapulse QS Nd:YAG 532 nm laser for the treatment of lentigines in dark-skinned patients.

The statistical variability of blood alcohol concentration measurements in drink-driving cases

Like many other places in the world, Hong Kong has drink-driving legislation which prohibits a driver from having in his blood alcohol exceeding a prescribed limit while in control of a motor vehicle. The accuracy of measuring this alcohol concentration is obviously of prime concern as an erroneous result can avert the administration of justice. The common practice is to deduct all errors from the measured value and compare the deducted value with the prescribed limit, so that the benefit of all errors of the measurement is given to the driver. It is therefore important for any laboratory responsible for measuring blood alcohol concentrations to identify and quantify all errors associated with the measurement. The present study examined 900 blood alcohol determinations carried out by the Hong Kong Government Laboratory (HKGL) on cases of suspected drink driving. The determinations were performed by 5 different analysts with two different sets of instruments during 1995-1997. Statistical analysis indicated that the instruments had no bearing on the random error or variability and that even though analyst was a significant factor on variability, the deviation from the mean so caused was only 0.3% and of no practical significance. When the systematic error introduced by the tolerance limits of the certified alcohol standards (purchased from the Laboratory of Government Chemists, UK) was taken into account, the total uncertainty (random plus systematic errors) of an alcohol determination at 99.5% confidence level was found to be 4%. It is recommended that laboratories engaged in blood alcohol determination should adopt similar statistical treatment of their analytical results to find out the error and to ensure that the results are independent of analyst and instrument used.

The identification of credit card encoders by hierarchical cluster analysis of the jitters of magnetic stripes

The relative bit density variation graphs of 207 specimen credit cards processed by 12 encoding machines were examined first visually, and then classified by means of hierarchical cluster analysis. Twenty-nine credit cards being treated as 'questioned' samples were tested by way of cluster analysis against 'controls' derived from known encoders. It was found that hierarchical cluster analysis provided a high accuracy of identification with all 29 'questioned' samples classified correctly. On the other hand, although visual comparison of jitter graphs was less discriminating, it was nevertheless capable of giving a reasonably accurate result.

Method of medians for lifetime data with Weibull models

The Weibull family of distributions is frequently used in failure time models. The maximum likelihood estimator is very sensitive to occurrence of upper and lower outliers, especially when the hazard function is increasing. We consider the method of medians estimator for the two-parameter Weibull model. As an M-estimator, it has a bounded influence function and is highly robust against outliers. It is easy to compute as it requires solving only one equation instead of a pair of equations as for most other M-estimators. Furthermore, no assumptions or adjustments are needed for the estimator when there are some possibly censored observations at either end of the sample. About 16 per cent of the largest observations and 34 per cent of the smallest observations may be censored without affecting the calculations. We also present a simple criterion to choose between the maximum likelihood estimator and the method of medians estimator to improve on the finite-sample efficiency of the Weibull model. Robust inference on the shape parameter is also considered. The usefulness with contaminated or censored samples is illustrated by examples on three lifetime data sets. A simulation study was carried out to assess the performance of the proposed estimator and the confidence intervals of a variety of contaminated Weibull models.

A simulation study comparing tests for the equality of coefficients of variation

The coefficient of variation is commonly used in medical and biological sciences. In this paper, several parametric and non-parametric tests for the equality of coefficients of variation in kappa populations are reviewed. Simulation studies are conducted to compare the sizes and power of these tests. It is found that the parametric tests perform well if the data are normally distributed, but perform poorly if otherwise. The non-parametric test, however, is rather robust against the underlying distribution. An example using data of the Quality Assurance Program from the Hong Kong Medical Technology Association in Haematology and Serology is provided. The insensitivity of the non-parametric test to outliers is demonstrated.

Amyopathic dermatomyositis in Hong Kong -- association with nasopharyngeal carcinoma

BACKGROUND

Amyopathic dermatomyositis (ADM) is a rare variant of dermatomyositis (DM) in which there is no apparent muscle involvement at initial presentation, but clinical and laboratory evidence of myopathy may appear later. Like DM, it has a known association with malignancy.

OBJECTIVE

To record the occurrence of ADM in Hong Kong during the period from January 1988 to June 1996, and to establish the types of carcinoma with which it is associated.

METHODS

The records of all patients diagnosed with ADM in three major dermatology clinics in Hong Kong were retrospectively studied to confirm the diagnosis and to look for any associated malignancy at any stage of the disease.

RESULTS

Between 1988 and 1996, six patients in Hong Kong (five men and one woman; mean age, 50 years) fulfilled the criteria of ADM. During a follow-up period ranging from 20 to 90 months (average, 35.6 months), none developed any evidence of myositis. Associated malignancy was found in the five male patients. There were three cases of nasopharyngeal carcinoma (NPC), one case of non-small cell carcinoma of the lung, and one case of metastatic carcinoma of the cervical lymph node of unknown primary. No carcinoma had developed in the female patient during a follow-up period of 90 months.

CONCLUSIONS

There is a strong association between ADM and NPC in Hong Kong.

Porokeratotic eccrine ostial and dermal duct naevus with dermatomal trunk involvement: literature review and report on the efficacy of laser treatment

Porokeratotic eccrine ostial and dermal duct naevus (PEODDN) is a rare, benign hamartomatous malformation involving the eccrine sweat duct. The existence of filiform keratinous plugs that represent cornoid lamellae overlying dilated infundibula of eccrine ducts is a distinctive feature and the presence of associated abnormal dermal ducts is frequent. We report a patient with PEODDN who exhibited lesions on the left side of her chest. Cases of PEODDN reported in the literature are reviewed. Our experience in treating this patient with ultrapulsed carbon dioxide laser is also presented.

Testing linkage equilibrium on allelic data between VNTR loci

We extend Geisser and Johnson's methods and propose simple tests for linkage equilibrium of fragment lengths between VNTR loci. The tests are shown to have asymptomatically normal or chi-square null distributions. They are applied to the reference databases of Asian populations, including the Hong Kong Chinese, Singapore Chinese, Singapore Malays, and Singapore Indians. It seems that there is little linkage disequilibrium in the data.

Comparison of Hae-III-generated VNTR profiles of Chinese in Hong Kong and Singapore

Some statistical analysis and experiments have been carried out on the single-locus VNTR reference databases collected separately from the Chinese in Hong Kong and Singapore to assess the issues of sample size and representativeness in the context of forensic science. We employed the bootstrap method and the Pearson chi-squared test for independence, and found that the different reference databases have very little effect in assessing the frequencies of occurrence of variable number of tandem repeats (VNTR) profiles. The results of random match probability assessment also indicate that the sample sizes studied appeared adequate to provide representative data. It has been found that a battery of four loci was enough to distinguish the 458 individuals under study.

Are convenience DNA samples significantly different?

In this paper, the issue of whether DNA databases collected by different convenience sampling methods are significantly different statistically is investigated. Testing the null hypothesis that the population probability or frequency distributions of DNA profiles under different sampling methods are the same is of interest in this investigation. Some statistical analyses are conducted on the single-locus VNTR databases collected from different sources by the Hong Kong Government Laboratory. The bootstrap, Monte Carlo simulation and significance tests including the Pearson's chi-squared, likelihood ratio, and Kolmogorov-Smirnov two-sample statistics are employed for testing the hypothesis. The results are promising that no probability values of the tests are smaller than 5%. In other words, there is not enough evidence to reject the null hypothesis at the 5% level, which provides more confidence for using the VNTR reference databases commonly collected by convenience sampling.