Topology design and performance analysis of an integrated communication network

A research study on the topology design and performance analysis for the Space Station Information System (SSIS) network is conducted. It is begun with a survey of existing research efforts in network topology design. Then a new approach for topology design is presented. It uses an efficient algorithm to generate candidate network designs (consisting of subsets of the set of all network components) in increasing order of their total costs, and checks each design to see if it forms an acceptable network. This technique gives the true cost-optimal network, and is particularly useful when the network has many constraints and not too many components. The algorithm for generating subsets is described in detail, and various aspects of the overall design procedure are discussed. Two more efficient versions of this algorithm (applicable in specific situations) are also given. Next, two important aspects of network performance analysis: network reliability and message delays are discussed. A new model is introduced to study the reliability of a network with dependent failures. For message delays, a collection of formulas from existing research results is given to compute or estimate the delays of messages in a communication network without making the independence assumption. The design algorithm coded in PASCAL is included as an appendix

A targeted gene panel that covers coding, non-coding and short tandem repeat regions improves the diagnosis of patients with neurodegenerative diseases

Genetic testing for neurodegenerative diseases (NDs) is highly challenging because of genetic heterogeneity and overlapping manifestations. Targeted-gene panels (TGPs), coupled with next-generation sequencing (NGS), can facilitate the profiling of a large repertoire of ND-related genes. Due to the technical limitations inherent in NGS and TGPs, short tandem repeat (STR) variations are often ignored. However, STR expansions are known to cause such NDs as Huntington\u27s disease and spinocerebellar ataxias type 3 (SCA3). Here, we studied the clinical utility of a custom-made TGP that targets 199 NDs and 311 ND-associated genes on 118 undiagnosed patients. At least one known or likely pathogenic variation was found in 54 patients; 27 patients demonstrated clinical profiles that matched the variants; and 16 patients whose original diagnosis were refined. A high concordance of variant calling were observed when comparing the results from TGP and whole-exome sequencing of four patients. Our in-house STR detection algorithm has reached a specificity of 0.88 and a sensitivity of 0.82 in our SCA3 cohort. This study also uncovered a trove of novel and recurrent variants that may enrich the repertoire of ND-related genetic markers. We propose that a combined comprehensive TGPs-bioinformatics pipeline can improve the clinical diagnosis of NDs

Nonlinear multidimensional scaling and visualization of earthquake clusters over space, time and feature space

International audienceWe present a novel technique based on a multi-resolutional clustering and nonlinear multi-dimensional scaling of earthquake patterns to investigate observed and synthetic seismic catalogs. The observed data represent seismic activities around the Japanese islands during 1997-2003. The synthetic data were generated by numerical simulations for various cases of a heterogeneous fault governed by 3-D elastic dislocation and power-law creep. At the highest resolution, we analyze the local cluster structures in the data space of seismic events for the two types of catalogs by using an agglomerative clustering algorithm. We demonstrate that small magnitude events produce local spatio-temporal patches delineating neighboring large events. Seismic events, quantized in space and time, generate the multi-dimensional feature space characterized by the earthquake parameters. Using a non-hierarchical clustering algorithm and nonlinear multi-dimensional scaling, we explore the multitudinous earthquakes by real-time 3-D visualization and inspection of the multivariate clusters. At the spatial resolutions characteristic of the earthquake parameters, all of the ongoing seismicity both before and after the largest events accumulates to a global structure consisting of a few separate clusters in the feature space. We show that by combining the results of clustering in both low and high resolution spaces, we can recognize precursory events more precisely and unravel vital information that cannot be discerned at a single resolution

Patterns of antihypertensive prescribing, discontinuation and switching among a Hong Kong Chinese population from over one million prescriptions

Hypertension is an alarming public health problem among Chinese. The present study evaluated the prescribing patterns, discontinuation and switching profiles of antihypertensive agents and their associated factors in one Hong Kong Chinese population. Data were retrieved from computerized records for patients prescribed anti-hypertensive agents in government primary care clinics of Hong Kong from January, 2004 to June, 2007. A total of 1,069,836 antihypertensive drug visits, representing 67,028 patients, were analyzed. The most commonly prescribed drugs were Calcium Channel Blockers (CCBs) (49%), b-Blockers (BBs) (46%) and Angiotensin-Converting Enzyme Inhibitors (ACEIs) (19%). Thiazide diuretic prescribing was low (13%) and on the decline (14% in 2004 to 12% in 2007). Prescribing of ACEIs was rising (16% in 2004 to 23% in 2007). Patients’ age, gender, and socio-economic status were independent predictors of class of anti-hypertensive prescribed but explained less than 3.5% of the variation observed. Drug discontinuation was highest for BBs (21%) and lowest for CCBs (12%). The high rates of discontinuation in BBs remained apparent after controlling for confounding variables. Switching was less common than discontinuation and was most likely with thiazide diuretics. To summarize, prescribing of CCBs and BBs were high and that of thiazide diuretics particularly low in this Chinese population when compared with international trends. CCBs may be a particularly favorable antihypertensive treatment in Chinese, given the high discontinuation rates of BBs and international guidelines advising against the use of BBs as first-line therapy. The low use of thiazide diuretics warrants further clinical and cost effectiveness studies among Chinese

Prospective Study on Retinal Nerve Fibre Layer Thickness Changes in Isolated Unilateral Retrobulbar Optic Neuritis

Purpose. To investigate the retinal nerve fibre layer (RNFL) thickness after unilateral acute optic neuritis using optical coherence tomography (OCT). Patients and Methods. This prospective cohort study recruited consecutive patients with a first episode of isolated, unilateral acute optic neuritis. RNFL thickness and visual acuity (VA) of the attack and normal fellow eye were measured at presentation and 3 months in both the treatment and nontreatment groups. Results. 11 subjects received systemic steroids and 9 were treated conservatively. The baseline RNFL thickness was similar in the attack and fellow eye (P≥0.4). At 3 months, the attack eye had a thinner temporal (P=0.02) and average (P=0.05) RNFL compared to the fellow eye. At 3 months, the attack eye had significant RNFL thinning in the 4 quadrants and average thickness (P≤0.0002) compared to baseline. The RNFL thickness between the treatment and nontreatment groups was similar at baseline and 3 months (P≥0.1). Treatment offered better VA at 3 months (0.1 ± 0.2 versus 0.3 ± 0.2 LogMAR, P=0.04). Conclusion. Generalized RNFL thinning occurred at 3 months after a first episode of acute optic neuritis most significantly in the temporal quadrant and average thickness. Visual improvement with treatment was independent of RNFL thickness

Quantum cryptography using balanced homodyne detection

We report an experimental quantum key distribution that utilizes balanced homodyne detection, instead of photon counting, to detect weak pulses of coherent light. Although our scheme inherently has a finite error rate, it allows high-efficiency detection and quantum state measurement of the transmitted light using only conventional devices at room temperature. When the average photon number was 0.1, an error rate of 0.08 and "effective" quantum efficiency of 0.76 were obtained.Comment: Errors in the sentence citing ref.[20] are correcte

Promoting resilience for HIV prevention in female sex workers in Hong Kong: a randomised controlled trial

Background: Female sex workers are considered a reservoir of HIV and their psychological health has a role to play in HIV infections. In China, commercial sex workers were reported to account for nearly 50% of heterosexual transmission of HIV. Therefore, HIV prevention targeted at mental health could be an innovative strategy in controlling the infection. We aimed to provide an evidence-based resilience-promoting intervention targeting mental health and ultimately safe sexual practices of female sex workers. Methods: This randomised controlled trial was done at three Hong Kong non-governmental organisations, namely Action for REACH OUT, JJJ Association, and the Society of Rehabilitation and Crime Prevention. Participants in this study were women (aged ≥18 years) who had worked as a sex worker in the previous 6 months. We randomly assigned participants to either intervention or usual care (control) according to a predetermined, computer-generated randomisation list. Both group facilitator and partcipants were unmasked to the group allocation, but an independent researcher who was masked to the treatment allocation administered the questionnaires. About half of the participants were permanent residents of Hong Kong whereas the other half were from mainland China. The six-session resilience-promoting intervention was designed to improve the coping skills, self-esteem, and self-efficacy (i.e. the belief of an individuals’ ability to control their actions to achieve desired goal), as measured by Brief-COPE, the Rosenberg Self-esteem Scale, and the Generalised Self- efficacy Scale of female sex workers. Questionnaires were administered by an independent assessor at baseline, post-treatment, and at 3-months follow-up. Participants in the control group received standard service, which included outreach visits, screening for HIV or sexually transmitted infections, and social activities provided by non-governmental organisations. The primary outcome of this study was the resilience scores measured by Connor-Davidson Resilience Scale. We analysed the differences between the two groups using the intention-to-treat analysis. This study was approved by the University of Hong Kong/Hospital Authority Hong Kong West Cluster Internal Review Board (UW 12-220). Verbal informed consent was obtained from all participants. Findings: 127 female sex workers were randomly assigned: 64 joined the control group and 63 joined intervention group. There were significant differences on the score on resilience, self-esteem, and mental health status between groups at post-intervention and 3- month follow-up. We found that condom use in the intervention group at 3-month follow-up was improved compared with the control group. After controlling for marital status and family size, improved resilience scores were associated with intervention group assignment (odds ratio 2∙95 [95% CI 1∙19–7∙35]; p=0∧021) and self-efficacy (1∧13 [1∧03–1∧24]; p=0∧006). Interpretation: Our findings suggest that resilience-promoting intervention programme was effective in improving the mental health status among Chinese female sex workers. This programme is an innovative approach to HIV prevention by promoting both psychological well-being and safe sex for this high-risk population. Funding: Council for the AIDS Trust Fund and General Research Grant, Research Grants Council, HKSAR

Clustering of childhood leukaemia in Hong Kong: association with the childhood peak and common acute lymphoblastic leukaemia and with population mixing.

Incidence data of childhood leukaemia (CL) in Hong Kong (1984-90) have been analysed for evidence of variation between small areas. All cases (n=261) were classified by morphological cell type, with the majority (n=205) being acute lymphoblastic leukaemia (ALL), and haematological review has permitted immunophenotypic classification for 73% of these. The data have been examined for evidence of spatial clustering within small census areas (TPUs) and for association with population mixing, with attention focused on those subgroups (especially the childhood peak of ALL--taken here to be diagnoses in children from 24 months up to the seventh birthday--and common ALL) which, it has been hypothesized, may be caused by unusual patterns of exposure and response to common infections. For the whole of Hong Kong, there was evidence of spatial clustering of ALL at ages 0-4 years (P = 0.09) and in the childhood peak (P<0.05). When these analyses were restricted to TPUs where extreme population mixing may have occurred, overall incidence was elevated and significant evidence of clustering was found for ALL (P<0.007) at these ages and for the common ALL in the childhood peak (P = 0.032). Replication of the analyses for subsets of leukaemia that were not dominated by the childhood peak of ALL found no evidence of clustering. This is the first investigation of an association between population mixing and childhood leukaemia in Asia and the first to include clustering and to consider particular subsets. The results are supportive of the 'infectious' aetiology hypothesis for subsets of childhood leukaemia, specifically common ALL in the childhood peak

Relating Quantum Information to Charged Black Holes

Quantum non-cloning theorem and a thought experiment are discussed for charged black holes whose global structure exhibits an event and a Cauchy horizon. We take Reissner-Norstr\"{o}m black holes and two-dimensional dilaton black holes as concrete examples. The results show that the quantum non-cloning theorem and the black hole complementarity are far from consistent inside the inner horizon. The relevance of this work to non-local measurements is briefly discussed.Comment: 14 pages, 2 figure

A prospective randomized, open-label trial comparing the safety and efficacy of dose sparing intradermal 2010/2011 trivalent influenza vaccine delivered by two different devices

Poster Abstract Session - Influenza Vaccines: no. 533BACKGROUND: We performed intradermal 2010/11 trivalent influenza vaccination (TIV) in adult subjects delivered by two different intradermal (ID) devices, using 20% and 60% of the standard dose and compared the immunogenicity and safety with full dose intramuscular (IM) immunization. METHODS: This is a prospective randomized trial conducted from December 2010 to March 2011, comprising chronically ill adults. Subjects were randomly assigned …postprin