2,792 research outputs found

    Energy Efficient Transmission over Space Shift Keying Modulated MIMO Channels

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    Energy-efficient communication using a class of spatial modulation (SM) that encodes the source information entirely in the antenna indices is considered in this paper. The energy-efficient modulation design is formulated as a convex optimization problem, where minimum achievable average symbol power consumption is derived with rate, performance, and hardware constraints. The theoretical result bounds any modulation scheme of this class, and encompasses the existing space shift keying (SSK), generalized SSK (GSSK), and Hamming code-aided SSK (HSSK) schemes as special cases. The theoretical optimum is achieved by the proposed practical energy-efficient HSSK (EE-HSSK) scheme that incorporates a novel use of the Hamming code and Huffman code techniques in the alphabet and bit-mapping designs. Experimental studies demonstrate that EE-HSSK significantly outperforms existing schemes in achieving near-optimal energy efficiency. An analytical exposition of key properties of the existing GSSK (including SSK) modulation that motivates a fundamental consideration for the proposed energy-efficient modulation design is also provided

    Contribution of discourse and morphosyntax skills to reading comprehension in Chinese dyslexic and typically developing children

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    This study aimed at identifying important skills for reading comprehension in Chinese dyslexic children and their typically developing counterparts matched on age (CA controls) or reading level (RL controls). The children were assessed on Chinese reading comprehension, cognitive, and reading-related skills. Results showed that the dyslexic children performed significantly less well than the CA controls but similarly to RL controls in most measures. Results of multiple regression analyses showed that word-level reading-related skills like oral vocabulary and word semantics were found to be strong predictors of reading comprehension among typically developing junior graders and dyslexic readers of senior grades, whereas morphosyntax, a text-level skill, was most predictive for typically developing senior graders. It was concluded that discourse and morphosyntax skills are particularly important for reading comprehension in the non-inflectional and topic-prominent Chinese system. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

    Colorectal carcinoma in Hong Kong: epidemiology and genetic mutations.

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    The incidence of colorectal carcinoma is rising at an alarming pace in Asian urban societies such as Hong Kong. Detailed examination of the epidemiological pattern and genetic mutation of colorectal cancer in the Hong Kong Chinese population is overdue. We compared the reported age incidence of colorectal carcinoma in Hong Kong with that of Scotland and other countries. Hong Kong showed a much higher incidence of colorectal carcinoma among the young age groups. By comparison with other countries, this raised incidence among the young appeared to be related to southern Chinese societies. The recent dramatic rise in colorectal cancer in Hong Kong was largely attributable to an increase in the over 50 years age group, while the young incidence remained unchanged. We also defined the mutation spectrum of p53 and Ki-ras in 67 unselected cases by direct DNA sequencing. Interestingly, insertion/deletion mutations in p53 from colorectal carcinoma in Hong Kong showed a significantly higher frequency (17.2%) than the Scottish data (0%) and the world database (6.6%), although the overall frequency of p53 mutation (43%) in Hong Kong was similar to others. The high incidence of colorectal carcinoma in young people and the raised proportion of frameshift mutations in p53 encourage further search for a genetic basis for susceptibility to this disease in the Hong Kong Chinese population

    Acupuncture for frozen-thawed embryo transfer cycles: A double-blind randomized controlled trial

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    The role of acupuncture on the pregnancy rate has not been evaluated in frozen-thawed embryo transfer (FET) cycles. This randomized double-blind study aimed to determine whether acupuncture performed on the day of FET improves clinical outcomes. On the day of FET, 226 patients were randomly allocated to either real or placebo acupuncture according to a computergenerated randomization list in sealed opaque envelopes. They received a session of real or placebo acupuncture for 25 min on site immediately after FET. The anxiety level and serum cortisol concentration were evaluated before and after real and placebo acupuncture. There were no significant differences in rates of overall pregnancy, clinical pregnancy, ongoing pregnancy, live birth and implantation in the placebo acupuncture group, when compared with the real acupuncture group. The anxiety level and serum cortisol concentration were similar for both groups. Only the placebo acupuncture group had significantly higher ongoing pregnancy (P = 0.022) and implantation rates (P = 0.038) than those who declined to join the study and received no acupuncture. In conclusion, comparable pregnancy and live birth rates of FET treatment were found in patients who had one session of real or placebo acupuncture after FET. © 2010, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.postprin

    Chinese herbal medicine for functional dyspepsia: systematic review of systematic reviews

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    © The Author(s), 2018. Background: Pharmacotherapy, including prokinetics and proton pump inhibitors for functional dyspepsia (FD) have limited effectiveness, and their safety has been recently questioned. Chinese herbal medicine (CHM) could be considered as an alternative. A systematic review (SR) of SRs was performed to evaluate the potential effectiveness and safety of CHM. Method: We conducted a comprehensive literature search for SRs with meta-analyses in eight international and Chinese databases. Pooled effect estimation from each meta-analysis was extracted. The AMSTAR instrument was used to assess the methodological quality of the included SRs. Results: A total of 14 SRs of mediocre quality assessing various CHMs, alone or in combination with conventional pharmacotherapy, were included. Meta-analyses showed that CHM was more effective than prokinetic agents for the alleviation of global dyspeptic symptoms. Three specific CHM formulae appeared to show superior results in the alleviation of global dyspeptic symptoms, including Si Ni San, modified Xiao Yao San and Xiang Sha Liu Jun Zi decoction. No significant difference in the occurrence of adverse events in using CHM or pharmacotherapy was reported. Conclusion: CHM can be considered as an alternative for the treatment of FD symptoms when prokinetic agents and proton pump inhibitors are contraindicated. Future trial design should focus on measuring changes in individual dyspeptic symptoms and differentiate the effectiveness of different CHM for postprandial distress syndrome and epigastric pain syndrome. A network meta-analysis approach should be used to explore the most promising CHM formula for FD treatment in the future

    Effects of a group-based lifestyle medicine for depression : a pilot randomized controlled trial

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    Given the growing evidence that a range of lifestyle factors are involved in the etiology of depression, a ‘lifestyle medicine’ approach can be potentially safe and cost-effective to prevent or treat depression. To examine the effects and acceptability of a group-based, integrative lifestyle medicine intervention as a standalone treatment for managing depressive symptoms, a pilot randomized controlled trial (RCT) was conducted in a Chinese adult population in 2018. Participants (n = 31) with PHQ-9 score above the cut-off of ≥ 10, which was indicative of moderate to severe depression, were recruited from the general community in Hong Kong and randomly assigned to lifestyle medicine group (LM group) or care-as-usual group (CAU group) in a ratio of 1:1. Participants in the LM group received 2-hour group sessions once per week for six consecutive weeks, which covered diet, exercise, mindfulness, psychoeducation, and sleep management. Linear mixed-effects model analyses showed that the LM group had a significant reduction in PHQ-9 scores compared to the CAU group at immediate posttreatment and 12-week posttreatment follow-up (d = 0.69 and 0.73, respectively). Moreover, there were significantly greater improvements in anxiety, stress, and insomnia symptoms (measured by DASS-21 and ISI) at all time points in the LM group (d = 0.42–1.16). The results suggests that our 6-week group-based, integrative lifestyle intervention program is effective in lowering depressive, anxiety, stress, and insomnia symptoms in the Chinese population. Further studies in clinical populations with a larger sample size and longer follow-up are warranted

    Solution of time domain PMCHW formulation for transient electromagnetic scattering from arbitrarily shaped 3-D dielectric objects

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    In this paper, we analyze the transient electromagnetic response from three-dimensional (3-D) dielectric bodies using a time domain PMCHW (Poggio, Miller, Chang, Harrington, Wu) integral equation. The solution method in this paper is based on the Galerkin’s method that involves separate spatial and temporal testing procedures. Triangular patch basis functions are used for spatial expansion and testing functions for arbitrarily shaped 3-D dielectric structures. The time domain unknown coefficients of the equivalent electric and magnetic currents are approximated by a set of orthonormal basis functions that are derived from the Laguerre functions. These basis functions are also used as the temporal testing. Use of the Laguerre polynomials as expansion functions characterizing the time variable enables one to handle the time derivative terms in the integral equation and decouples the space-time continuum in an analytic fashion. We also propose an alternative formulation using a differential form of time domain PMCHW equation with a different expansion for the equivalent currents. Numerical results computed by the two proposed methods are presented and compared
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