308 research outputs found

    Theoretical Design and FPGA-Based Implementation of Higher-Dimensional Digital Chaotic Systems

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    Traditionally, chaotic systems are built on the domain of infinite precision in mathematics. However, the quantization is inevitable for any digital devices, which causes dynamical degradation. To cope with this problem, many methods were proposed, such as perturbing chaotic states and cascading multiple chaotic systems. This paper aims at developing a novel methodology to design the higher-dimensional digital chaotic systems (HDDCS) in the domain of finite precision. The proposed system is based on the chaos generation strategy controlled by random sequences. It is proven to satisfy the Devaney's definition of chaos. Also, we calculate the Lyapunov exponents for HDDCS. The application of HDDCS in image encryption is demonstrated via FPGA platform. As each operation of HDDCS is executed in the same fixed precision, no quantization loss occurs. Therefore, it provides a perfect solution to the dynamical degradation of digital chaos.Comment: 12 page

    The association of gender diversity in the compensation committee and CEO remuneration: evidence form UK

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    Abstract Executive compensation has been a hot issue for investors, policymakers and scholars. The global trend of enhancing female representation on board also drives the study related to gender diversity and corporate governance effectiveness. This paper aims to investigate that whether the gender diversity of the compensation committee is negative associated with the CEO pay setting, and whether the presence of female directors in the committee could improve the link between the CEO remuneration and firm performance. Based on the result of panel regression method and the sample collected from FTSE 350 public companies in the London Stock Exchange during 2012 to 2018 financial year period, the results suggest that the integration of female directors in the sub of boardroom may have little impact on CEO pay package, and gender diversity of compensation committee does not significantly improve the pay-performance link. Key words: gender diversity, compensation committee, CEO compensatio

    Willingness, preferred ways and potential barriers to use pre-exposure prophylaxis for HIV prevention among men who have sex with men in China

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    Objective To explore willingness and preferred ways to use HIV pre-exposure prophylaxis (PrEP), factors associated with willingness, and potential barriers to PrEP use among men who have sex with men (MSM) in Changsha, China. Design A cross-sectional survey was conducted from 25 June to 31 August 2019. Two hundred and fifty-five MSM were recruited from three community-based organisations (CBOs) in Changsha City. Willingness and potential barriers to use PrEP were examined using researcher-created scales. Univariate and multivariate logistic regression was used to analyse the factors associated with willingness to use PrEP. P values <0.05 were considered significant. Setting Three MSM inclusive CBOs in Changsha, Hunan Province, China. Participants 255 HIV-negative MSM were recruited through their CBOs with snowball sampling. Results Less than half of the participants (43.1%) had heard of PrEP and 15.3% were willing to use PrEP. The participants reported higher willingness to use event-driven PrEP (3.70±0.07) than daily PrEP (2.65±0.07). Higher self-rated risk and fear of contracting HIV (OR: 14.47, 95% CI 2.19 to 95.53), awareness of PrEP (OR: 4.20, 95% CI 1.64 to 10.73), sharing one's own sexual orientation with parents or siblings (OR: 2.52, 95% CI 1.54 to 7.20) and having a university education or above (OR:0.29, 95% CI 0.12 to 0.72) were associated with willingness to use PrEP. Only 12.2% of the sample was concerned about potential barriers to PrEP use. Conclusion Efforts to improve awareness and knowledge of PrEP, teach self-evaluation of HIV infection risk and provide social and emotional support for MSM are needed to scale up PrEP implementation in China. © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Wendy Cross, Louisa Lam and Bixwajit Banik” is provided in this record*

    Polymorphisms of the _ENPP1_ gene are not associated with type 2 diabetes or obesity in the Chinese Han population

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    *Objective:* Type 2 Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia and with a major feature of insulin resistance. Genetic association studies have suggested that _ENPP1_ might play a potential role in susceptibility to type 2 diabetes and obesity. Our study aimed to examine the association between _ENPP1_ and type 2 diabetes and obesity.&#xd;&#xa;&#xd;&#xa;*Design:* Association study between two SNPs, rs1044498 (K121Q) and rs7754561 of ENPP1 and diabetes and obesity in the Chinese Han population.&#xd;&#xa;&#xd;&#xa;*Subjects:* 1912 unrelated patients (785 male and 1127 female with a mean age 63.8 &#xb1; 9 years), 236 IFG/IGT subjects (83 male and 153 female with a mean age 64 &#xb1; 9 years) and 2041 controls (635 male and 1406 female with a mean age 58 &#xb1; 9 years).&#xd;&#xa; &#xd;&#xa;*Measurements:* Subjects were genotyped for two SNPs using TaqMan technology on an ABI7900 system and tested by regression analysis.&#xd;&#xa;&#xd;&#xa;*Results:* By logistic regression analysis, rs1044498 (K121Q) and rs7754561 showed no statistical association with type 2 diabetes, obesity under additive, dominant and recessive models either before or after adjusting for sex and age. Haplotype analysis found a marginal association of haplotype C-G (p=0.05) which was reported in the previous study.&#xd;&#xa;&#xd;&#xa;*Conclusion:* Our investigation did not replicated the positive association found previously and suggested that the polymorphisms of _ENPP1_ might not play a major role in the susceptibility to type 2 diabetes or obesity in the Chinese Han population

    Condom use consistency and associated factors among college student men who have sex with men from seven colleges in Changsha city : a cross-sectional survey

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    Background: College student men who have sex with men (MSM) are at high risk for HIV infection due to multiple social and behavioral factors. Consistent condom use is nationally advocated for HIV prevention. This study explored the sexual behaviors and factors associated with condom use consistency in the past six months among college student MSM from seven colleges in Hunan Province, China. Methods: A cross-sectional survey was conducted from September 2017 to March 2018. Condom use consistency, sexual behaviors, HIV testing performance, substance use, and alcohol consumption were examined using researcher-created questionnaires. Condom use self-efficacy and HIV-related knowledge were assessed using the Condom Use Self-Efficacy Scale and the unified National AIDS Sentinel Surveillance Questionnaire. Univariate and multivariate logistic regressions were used. P <0.05 was considered significant. Results: In the 214 respondents, the rate of consistent condom use was 56% (n = 119) during the past six months. Participants who were studying at first-tier universities (odds ratio [OR]: 2.522, 95% confidence interval [CI]: 1.255–5.067) and had higher scores for condom use self-efficacy (OR: 2.617, 95% CI: 1.462–4.685) were more likely to report consistent condom use than the others. The risk factor was having suspicious symptoms of sexually transmitted diseases (OR: 0.357, 95% CI: 0.163–0.780). Conclusion: Numerous students were at high risk of HIV infection with inconsistent condom use. Comprehensive and specific topics about safe sex education from parents and peers should be offered on campuses in China. © 2021 Wang et al

    A Systematic Methodology for Multi-Images Encryption and Decryption Based on Single Chaotic System and FPGA Embedded Implementation

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    A systematic methodology is developed for multi-images encryption and decryption and field programmable gate array (FPGA) embedded implementation by using single discrete time chaotic system. To overcome the traditional limitations that a chaotic system can only encrypt or decrypt one image, this paper initiates a new approach to design n-dimensional (n-D) discrete time chaotic controlled systems via some variables anticontrol, which can achieve multipath drive-response synchronization. To that end, the designed n-dimensional discrete time chaotic controlled systems are used for multi-images encryption and decryption. A generalized design principle and the corresponding implementation steps are also given. Based on the FPGA embedded hardware system working platform with XUP Virtex-II type, a chaotic secure communication system for three digital color images encryption and decryption by using a 7D discrete time chaotic system is designed, and the related system design and hardware implementation results are demonstrated, with the related mathematical problems analyzed

    Cryoballoon vs. laser balloon ablation for atrial fibrillation: a meta-analysis

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    BackgroundCryoballoon ablation (CBA) and laser balloon ablation (LBA) are two innovative ways for the treatment of atrial fibrillation (AF). This study aimed to evaluate the efficacy and safety of cryoballoon ablation and laser balloon ablation in patients with AF.MethodsWe searched Pubmed, Embase, Ovid, Web of Science and other databases for comparative trials comparing CB and LB ablation in the treatment of AF, from establishment of database to August, 2023.ResultsA total of 13 studies and 3,582 patients were included (CBA, n = 2,308; LBA, n = 1,274). There was no difference between CBA and LBA in acute PVI rate per vein, 12-months recurrence rate of AF, 12-months recurrence rate of atrial arrhythmia, occurrence rate of pericardial tamponade, occurrence rate of inguinal complications. LBA presented a lower acute PVI rate per patients (CBA 97.0% vs. LBA 93.4%, RR = 1.04, 95%CI: 1.01–1.07). Transient nerve palsy was more likely to occur after CBA (CBA 2.7% vs. LBA 0.7%, RR = 4.25, 95%CI: 2.06–8.76). However, the occurrence of persistent nerve palsy between CBA and LBA groups were similar (CB 1.4% vs. LB 1.0%, RR = 1.09, 95%CI: 0.55–2.14). In terms of procedural duration, the procedural time of CBA was shorter than that of LBA (WMD = −26.58, 95%CI: −36.71–16.46).ConclusionsCompared with LBA, CBA had a shorter procedural duration. There was a higher incidence of transient but not persistent phrenic nerve palsy after CBA.Systematic Review Registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?RecordID=272607 Identifier (CRD42021272607)

    Willingness, preferred ways and potential barriers to use pre-exposure prophylaxis for HIV prevention among men who have sex with men in China

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    Objective To explore willingness and preferred ways to use HIV pre-exposure prophylaxis (PrEP), factors associated with willingness, and potential barriers to PrEP use among men who have sex with men (MSM) in Changsha, China. Design A cross-sectional survey was conducted from 25 June to 31 August 2019. Two hundred and fifty-five MSM were recruited from three community-based organisations (CBOs) in Changsha City. Willingness and potential barriers to use PrEP were examined using researcher-created scales. Univariate and multivariate logistic regression was used to analyse the factors associated with willingness to use PrEP. P values <0.05 were considered significant. Setting Three MSM inclusive CBOs in Changsha, Hunan Province, China. Participants 255 HIV-negative MSM were recruited through their CBOs with snowball sampling. Results Less than half of the participants (43.1%) had heard of PrEP and 15.3% were willing to use PrEP. The participants reported higher willingness to use event-driven PrEP (3.70±0.07) than daily PrEP (2.65±0.07). Higher self-rated risk and fear of contracting HIV (OR: 14.47, 95% CI 2.19 to 95.53), awareness of PrEP (OR: 4.20, 95% CI 1.64 to 10.73), sharing one’s own sexual orientation with parents or siblings (OR: 2.52, 95% CI 1.54 to 7.20) and having a university education or above (OR:0.29, 95% CI 0.12 to 0.72) were associated with willingness to use PrEP. Only 12.2% of the sample was concerned about potential barriers to PrEP use. Conclusion Efforts to improve awareness and knowledge of PrEP, teach self-evaluation of HIV infection risk and provide social and emotional support for MSM are needed to scale up PrEP implementation in China
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