Perception and production of lexical tones by young children

Thesis (B.Sc)--University of Hong Kong, 2006."A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2006."Also available in print.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

Research on Multi-leg Inventory Control Based on Passenger Choice

To remedy the lack of mathematical programming and the Expected Marginal Seat Revenue (EMSR) model for multi-leg seat inventory control, this paper proposes a method based on passenger choice. Except for data about which seats passengers decide to opt for, there is no need to obtain distributions of passengers’ demands or other “a priori” information. The proposed method can discover the real factors that affect passengers’ choices, and then estimate the probabilities of seat choices and the revenue according to the weights of the factors. Simulated experiments and comparison with the shadow price method and the virtual “bucket” method confirm the feasibility and effectiveness of the proposed method in seat inventory control for multi-leg flights

The Social fMRI: Measuring, Understanding, and Designing Social Mechanisms in the Real World

A key challenge of data-driven social science is the gathering of high quality multi-dimensional datasets. A second challenge relates to design and execution of structured experimental interventions in-situ, in a way comparable to the reliability and intentionality of ex-situ laboratory experiments. In this paper we introduce the Friends and Family study, in which a young-family residential community is transformed into a living laboratory. We employ a ubiquitous computing approach that combines extremely rich data collection in terms of signals, dimensionality, and throughput, together with the ability to conduct targeted experimental interventions with study populations. We present our mobile-phone-based social and behavioral sensing system, which has been deployed for over a year now. Finally, we describe a novel tailored intervention aimed at increasing physical activity in the subject population. Results demonstrate the value of social factors for motivation and adherence, and allow us to quantify the contribution of different incentive mechanisms.U.S. Army Research Laboratory (Cooperative Agreement Number W911NF-09-2-0053)United States. Air Force Office of Scientific Research (Award FA9550-10-1-0122

A Risk Identification Method of Virtual Enterprise

Virtual enterprise is the potential mode of future enterprise under global economic environment and the risk management for it is a popular research area recently. Risk identification is the key phrase of risk management. Considering the risk identification problem in the virtual enterprise, a new identification method based on the BP network is provided in this paper. Using this method and the data related to the problem, the possible to take place of the risks could be obtained by training the neural network, so that risks can be investigated in time and managed effectively. The simulation results prove its validit

Gestational Exposure to Antidepressants and Risk of Seizure in Offspring: A systematic review and meta-analysis

In spite of the preliminary evidence suggesting a link between gestational use of antidepressant and neurodevelopmental disorders in their offspring, the association between maternal use of antidepressants during pregnancy and the risk of neurologically-related adverse outcomes such as neonatal seizure is still unclear. This study summarises the available evidence on the association between gestational exposure to any antidepressants and the risk of seizure in neonates and children. We found that gestational antidepressant exposure is associated with a 2.3-fold higher incidence of seizure in offspring. Although a causal relationship cannot be confirmed in view of other potential confounders, our findings warrant future research on related clinical aspects, and possibly more careful monitoring of foetal neurodevelopment in pregnant women taking antidepressants during pregnancy. However, this does not suggest the abrupt withdrawal of antidepressants during pregnancy for all cases at risk of seizure in offspring as this must be balanced with the risk of negative consequences caused by untreated maternal depression, and decision-making should be individualised for each patient

Effectiveness of Facebook Groups and Pages on Participant Recruitment Into a Randomized Controlled Trial During the COVID-19 Pandemic: Descriptive Study

BACKGROUND: In response to the unprecedented challenges posed by the COVID-19 pandemic, conventional recruitment approaches were halted, causing the suspension of numerous clinical trials. Previously, Facebook (Meta Platforms, Inc) has emerged as a promising tool for augmenting participant recruitment. While previous research has explored the use of Facebook for surveys and qualitative studies, its potential for recruiting participants into randomized controlled trials (RCTs) remains underexplored. OBJECTIVE: This study aimed to comprehensively examine the effectiveness of using Facebook groups and pages to facilitate participant recruitment during the COVID-19 pandemic for an RCT on the effectiveness of a remote parenting program, 1-2-3 Magic, in families who have children with attention-deficit/hyperactivity disorder (ADHD) in the United Kingdom. METHODS: We disseminated 5 Facebook posts with an attached digital flyer across 4 prominent ADHD UK support groups and pages run by the National Attention Deficit Disorder Information and Support Services, reaching an audience of around 16,000 individuals over 2 months (January 7 to March 4, 2022). Eligibility criteria mandated participants to be parents or caregivers of a child with diagnosed ADHD aged 12 years or younger, be residing in the United Kingdom, have access to stable internet, and have a device with the Zoom (Zoom Video Communications) app. Participants were required to have never attended 1-2-3 Magic training previously. Prospective participants expressed their interest through Microsoft Forms (Microsoft Corporation). The trial aimed to recruit 84 parents. It is important to note that the term "parent" or "caregiver" in the RCT and in this study within a trial refers to anybody who has legal responsibility for the child. RESULTS: Overall, 478 individuals registered their interest through Microsoft Forms within the stipulated 2-month window. After the eligibility check, 135 participants were contacted for a baseline meeting through Zoom. The first 84 participants who attended a baseline meeting and returned a completed consent form were enrolled. Subsequently, another 16 participants were added, resulting in a final sample of 100 participants. This recruitment strategy incurred negligible expenses and demanded minimal human resources. The approach yielded favorable outcomes by efficiently attracting eligible participants in a condensed time frame, transcending geographical barriers throughout the United Kingdom, which would have been tedious to achieve through traditional recruitment methods. CONCLUSIONS: Our experience demonstrated that digital flyers posted in the targeted Facebook groups were a cost-effective and quick method for recruiting for an RCT, which opened during the COVID-19 pandemic when lockdown restrictions were in place in the United Kingdom. Trialists should consider this low-cost recruitment intervention for trials going forward, and in the case of a global pandemic, this novel recruitment method enabled the trial to continue where many have failed. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number (ISRCTN) 15281572; https://www.isrctn.com/ISRCTN15281572

The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2

On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 $\pm$ 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 $\times$ 1.95 km) $\pm$10$\%$, respectively, and the direction of the +$z$ axis is estimated to be (250$\pm$5$^\circ$, 63$\pm$5$^\circ$) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.Comment: 21 pages, 3 figures, 1 tabl

Associations between prenatal exposure to antipsychotics and attention-deficit/hyperactivity disorder, autism spectrum disorder, preterm birth and small for gestational age: a population-based cohort study

Importance: The risk of birth and neurodevelopmental complications with prenatal exposure to antipsychotics is unclear. / Objective: To evaluate the association between prenatal antipsychotics exposure and the risk of birth and neurodevelopmental problems. / Design, Setting, Participants: This population-based cohort study included children born between 2001–2015 with follow-up to 2019, identified by the Hong Kong Clinical Data Analysis and Reporting System. Pregnancies with maternal antidepressant/lithium exposure were removed. Primary analyses compared gestational-exposed and gestational non-exposed with propensity score fine-stratification. Additional analyses included gestational-exposed versus past-exposed and sibling-matched analysis to evaluate the effect of confounding by indication. / Exposures: Prenatal antipsychotic exposure. Main outcomes and measures: Preterm birth (<37 gestational weeks), small for gestational age (birth weight <2 standard deviations below the mean for gestational age), and first diagnosis of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in children. / Results: The cohorts included 333,749 mother-child pairs for ADHD and 411,251 pairs for ASD/preterm birth/small for gestational age analyses. There were 13,196 children (3.95%) diagnosed with ADHD, 8,715 (2.12%) with ASD, 33,891 (8.24%) preterm, and 7,009 (1.70%) small for gestational age. The weighted hazard ratio (wHR) was 1.16 (95% confidence interval [CI]=0.83-1.61) for ADHD and 1.06 (95%CI=0.70-1.60) for ASD, while the weighted odds ratio (wOR) was 1.40 (95%CI=1.13-1.75) for preterm birth and 1.36 (95%CI=0.86-2.14) for small for gestational age, when comparing gestational-exposed to gestational non-exposed. Additional analyses showed no association when comparing gestational-exposed to past-exposed (ADHD: wHR=0.99, 95%CI=0.60-1.61); ASD: wHR=1.10, 95%CI=0.58-2.08; preterm birth: wOR=0.93, 95%CI=0.70-1.24; small for gestational age: wOR=1.21, 95%CI=0.66-2.20), and in sibling-matched analysis (ADHD: wHR=0.41, 95%CI=0.04-4.93; ASD: wHR=0.90, 95%CI=0.40-2.01; preterm birth: wOR=1.25, 95%CI=0.85-1.82; small for gestational age: wOR=0.86, 95%CI=0.32-2.31). / Conclusions and Relevance: We found no evidence that prenatal antipsychotics exposure increased the risk of ADHD, ASD or small for gestational age. In the primary analysis, there was a small increased risk of preterm birth, but additional analyses comparing gestational-exposed to past-exposed and comparing gestational exposed to gestational non-exposed siblings did not support an increased risk. Given the benefits of treating psychosis during pregnancy, our findings do not support a recommendation for women to stop their regular antipsychotic treatment during pregnancy

A multi band study of the optically dark GRB 051028

Observations were made of the optical afterglow of GRB 051028 with the Lulin observatory's 1.0 m telescope and the WIDGET robotic telescope system. R band photometric data points were obtained on 2005 October 28 (UT), or 0.095-0.180 days after the burst. There is a possible plateau in the optical light curve around 0.1 days after the burst; the light curve resembles optically bright afterglows (e.g. GRB 041006, GRB 050319, GRB060605) in shape of the light curve but not in brightness. The brightness of the GRB 051028 afterglow is 3 magnitudes fainter than that of one of the dark events, GRB 020124. Optically dark GRBs have been attributed to dust extinction within the host galaxy or high redshift. However, the spectrum analysis of the X-rays implies that there is no significant absorption by the host galaxy. Furthermore, according to the model theoretical calculation of the Ly$\alpha$ absorption to find the limit of GRB 051028's redshift, the expected $R$ band absorption is not high enough to explain the darkness of the afterglow. While the present results disfavor either the high-redshift hypothesis or the high extinction scenario for optically dark bursts, they are consistent with the possibility that the brightness of the optical afterglow, intrinsically dark.Comment: 5page, 5 figures, 1 table, accepted for publication in PASJ Letter. PASJ styl

Testing the External Shock Model of Gamma-Ray Bursts using the Late-Time Simultaneous Optical and X-ray Afterglows

We study the ``normal'' decay phase of the X-ray afterglows of gamma-ray bursts (GRBs), which follows the shallow decay phase, using the events simultaneously observed in the R-band. The classical external shock model -- in which neither the delayed energy injection nor time-dependency of shock micro-physics is considered -- shows that the decay indices of the X-ray and R-band light curves, $\alpha_{\rm X}$ and $\alpha_{\rm O}$, obey a certain relation, and that in particular, $\alpha_{\rm O}-\alpha_{\rm X}$ should be larger than -1/4 unless the ambient density increases with the distance from the central engine. For our selected 14 samples, we have found that 4 events violate the limit at more than the 3$\sigma$ level, so that a fraction of events are outliers of the classical external shock model at the ``normal'' decay phase.Comment: Accepted for publication in ApJL. 12 page, 2 figures, 2 table