Cross layer designs for OFDMA wireless systems with heterogeneous delay requirements

This paper investigates a cross layer scheduling scheme for OFDMA wireless system with heterogeneous delay requirements. Unlike most existing cross layer designs which take a decoupling approach, our design considers both queueing theory and information theory in modeling the system dynamics. The cross layer design is formulated as an optimization of total system throughput, subject to individual user's delay constraint and total base station transmit power constraint. The optimal scheduling algorithm for the delay-sensitive cross layer optimization is to dynamically allocate radio resources based on users' channel state information, source statistics and delay requirements. Specifically, optimal power allocation was found to be multilevel water-filling where urgent users have higher water-filling levels, while optimal subcarrier allocation strategy is shown to be achievable by low complexity greedy algorithm. Simulation results also show the proposed jointly optimal power and subcarrier allocation policy can provide substantial throughput gain with all delay constraints being satisfied. © 2006 IEEE.published_or_final_versio

Cross-layer design for OFDMA wireless systems with heterogeneous delay requirements

This paper proposes a cross-layer scheduling scheme for OFDMA wireless systems with heterogeneous delay requirements. We shall focus on the cross-layer design which takes into account both queueing theory and information theory in modeling the system dynamics. We propose a delay-sensitive cross-layer design, which determines the optimal subcarrier allocation and power allocation policies to maximize the total system throughput, subject to the individual user's delay constraint and total base station transmit power constraint. The delay-sensitive power allocation was found to be multilevel water-filling in which urgent users have higher water-filling levels. The delay-sensitive subcarrier allocation strategy has linear complexity with respect to number of users and number of subcarriers. Simulation results show that substantial throughput gain is obtained while satisfying the delay constraints when the delay-sensitive jointly optimal power and subcarrier allocation policy is adopted. © 2007 IEEE.published_or_final_versio

A coliform-targeted metagenomic method facilitating human exposure estimates to Escherichia coli-borne antibiotic resistance genes.

This is the author accepted manuscript. The final version is available from Oxford University Press via the DOI in this record.Background: Antimicrobial resistance and the spread of antibiotic resistance genes (ARGs) pose a threat to human health. Community-acquired infections resistant to treatment with first-line antibiotics are increasing, and there are few studies investigating environmental exposures and transmission. Aim: Our objective is to develop a novel targeted metagenomic method to quantify the abundance and diversity of ARGs in a faecal indicator bacterium, and to estimate human exposure to resistant bacteria in a natural environment. Approach: Sequence data from Escherichia coli metagenomes from 13 bathing waters in England were analysed using the ARGs Online Analysis Pipeline to estimate the abundance and diversity of resistance determinants borne by this indicator bacterium. These data were averaged over the 13 sites and used along with data on the levels of E. coli in English bathing waters in 2016 and estimates of the volume of water that water users typically ingest in an average session of their chosen activityto quantify the numbers of ARGs that water users ingest. Findings: Escherichia coli in coastal bathing waters were found to harbour on average 1.24 ARGs per cell. Approximately 2.5 million water sports sessions occurred in England in 2016 that resulted in water users ingesting at least 100 E. coli-borne ARGs.This work was supported by the University of Exeter and the Chinese University of Hong Kong

On the architecture of H.264 to H.264 homogeneous transcoding platform

2007-2008 > Academic research: refereed > Invited conference paperVersion of RecordPublishe

Quality of Care for Older Patients with Non-Cancer Diagnoses under the End-of-Life Care Program

Background: End-of-life (EOL) care is an important part of geriatric medicine in view of rapidly ageing populations in the world. Aim: We aimed to evaluate the quality of care for older patients with non-cancer terminal illnesses, who died in 2010, under the EOL care program of an academic medical unit in Hong Kong. This unit consisted of an acute hospital, Prince of Wales Hospital (PWH) and a convalescence hospital (Shatin Hospital, SH). Methods: This was a retrospective hospital-based audit of clinical effectiveness of the EOL service. We reviewed the quality of patient care during the final seven days of life. The quality of care was evaluated based on the compliance rates of five selected goals and the adoption of futile life-sustaining procedures and treatments. Results: Case records of 129 patients in the EOL care program were analyzed. Two goals, including minimization of regular monitoring of vital signs and no blood taking, achieved over 70% compliance at SH and 0% at PWH. The compliance rates of discontinuation of non-essential medications were 46.4% in SH and 47.1% in PWH; and the compliance rates of switching essential medications to non-oral routes were 63.4% in SH and 70.6% in PWH (not statistically significant). The compliance rates of using as-required intravenous or subcutaneous medications were extremely low (<2%) at both hospitals. All futile life-sustaining procedures and treatments were initiated at the PWH. Conclusions: We demonstrated significant differences in the quality of EOL care between the acute hospital and convalescence hospital. Greater emphasis on specialist training and education with allocation of resources may improve the EOL care in both settings.published_or_final_versio

Professional breastfeeding support to increase the exclusivity and duration of breastfeeding: a randomised controlled trial

Modest postnatal support interventions such as providing early support with breastfeeding and conducting brief weekly telephone support can improve both the duration and exclusivity of breastfeeding.published_or_final_versio

Professional breastfeeding support for first-time mothers: a multicentre cluster randomised controlled trial

Conference Theme: Translating Health Research into Policy and Practice for Health of the PopulationPoster Presentations: Delivery of Health Servicespublished_or_final_versio

Professional breastfeeding support for first-time mothers: a multicentre cluster randomised controlled trial

Objective To evaluate the effect of two postnatal professional support interventions on the duration of any and exclusive breastfeeding. Design Multicentre, three-arm, cluster randomised controlled trial. Population A cohort of 722 primiparous breastfeeding mothers with uncomplicated, full-term pregnancies. Methods The three study interventions were: (1) standard postnatal maternity care; (2) standard care plus three in-hospital professional breastfeeding support sessions, of 30–45 minutes in duration; or (2) standard care plus weekly post-discharge breastfeeding telephone support, of 20–30 minutes in duration, for 4 weeks. The interventions were delivered by four trained research nurses, who were either highly experienced registered midwives or certified lactation consultants. Main outcome measures Prevalence of any and exclusive breastfeeding at 1, 2, and 3 months postpartum. Results Rates of any and exclusive breastfeeding were higher among participants in the two intervention groups at all follow-up points, when compared with those who received standard care. Participants receiving telephone support were significantly more likely to continue any breastfeeding at 1 month (76.2 versus 67.3%; odds ratio, OR 1.63, 95% confidence interval, 95% CI 1.10–2.41) and at 2 months (58.6 versus 48.9%; OR 1.48, 95% CI 1.04–2.10), and to be exclusively breastfeeding at 1 month (28.4 versus 16.9%; OR 1.89, 95% CI 1.24–2.90). Participants in the in-hospital support group were also more likely to be breastfeeding at all time points, but the effect was not statistically significant. Conclusions Professional breastfeeding telephone support provided early in the postnatal period, and continued for the first month postpartum, improves breastfeeding duration among first-time mothers. It is also possible that it was the continuing nature of the support that increased the effectiveness of the intervention, rather than the delivery of the support by telephone specifically.postprin

High prevalence of mixed infections by Helicobacter pylori in Hong Kong: Metronidazole sensitivity and overall genotype

Background: Diversity in metronidazole susceptibility and genotypes of Helicobacter pylori have been reported with varying results in different areas. Aims: To investigate the prevalence of multiple strain infection in a symptomatic Chinese population and to determine the metronidazole susceptibility pattern and genotypic characteristics of these infecting strains. Methods: Gastric biopsies from antrum, body and cardia were taken during upper endoscopy in symptomatic patients referred to our department. Pooled cultures and single colony isolates were obtained and tested for metronidazole susceptibility and random amplified polymorphic DNA (RAPD) fingerprint patterns. Results: A total of 461 isolates were successfully cultured from 46 patients. Fifty-seven per cent of subjects had metronidazole-resistant strains. Among them, 77% carried a mixture of sensitive and resistant strains, non-uniformly distributed in the gastric mucosa. Mixed genotypes were found by RAPD typing in 24% of subjects. These did not correlate with the metronidazole susceptibility/resistance pattern. Conclusion: H. pylori infections with mixed metronidazole sensitive/resistant strains and mixed genotypes are common in Hong Kong. This makes it prudent to use bacterial strains from several biopsy sites when testing for traits such as drug resistance or virulence in relation to disease.postprin

High prevalence of Helicobacter pylori infection with dual resistance to metronidazole and clarithromycin in Hong Kong

Background: Metronidazole resistance is a common problem in most Asian countries, and clarithromycin has been widely used in Hong Kong. Aim: To determine the prevalence of Helicobacter pylori strains resistant to metronidazole and clarithromycin in Hong Kong and to assess the effect on eradication rates. Also to determine the genetic mutation in relation to phenotypic divergence in clarithromycin-resistant strains. Methods: H. pylori were cultured from gastric biopsies obtained from 87 patients during upper endoscopy. Minimal inhibitory concentrations of metronidazole and clarithromycin were determined by Etest and agar dilution methods. Mutations in clarithromycin-resistant strains were identified by polymerase chain reaction and restriction analysis. Random amplified polymorphic DNA fingerprinting was performed on clarithromycin-resistant and susceptible isolates. Results: The prevalences of H. pylori strains resistant to metronidazole and clarithromycin were 49.4% and 10.8%, respectively, in Hong Kong. Dual resistance to metronidazole and clarithromycin were found in 7.2% of patients. The agreement between E-test and agar dilution methods was determined by error-rate bound analysis as 95.4% for metronidazole and 100% for clarithromycin. Dual resistant strains reduced the eradication rate to 66.7%. Among clarithromycin-resistant strains tested, all were due to A2144G point mutation in 23S rRNA gene. Random amplified polymorphic DNA fingerprinting suggested various phenotypically mixed populations. Conclusions: The prevalence of metronidazole-resistant H. pylori strains remained static whilst the prevalence of clarithromycin-resistant strains was not rare in Hong Kong. An alarming 7.2% of patients were resistant to both the antimicrobials, which had a definite impact on treatment success. All cases of resistance to clarithromycin were due to A2144G mutation in 23S rRNA of H. pylori.postprin