Dengue virus is hyperendemic in Nigeria from 2009 to 2020: A contemporary systematic review

Backround: Data on Dengue virus (DENV) infection prevalence, geographic distribution and risk factors are necessary to direct appropriate utilization of existing and emerging control strategies. This study aimed to determine the pooled prevalence, risk factors of DENV infection and the circulating serotypes within Nigeria from January 1, 2009 to December 31, 2020. Materials and methods: Twenty-one studies out of 2,215 available articles were eligible and included for this systematic review. Relevant articles were searched, screened and included in this study according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) criteria. The risk of bias in primary studies was assessed by Cochrane's method. Heterogeneity of pooled prevalence was calculated using the chi-square test on Cochrane's Q statistic, which was quantified by I-square values. The random-effects analyses of proportions were used to determine the pooled prevalence of DENV antibodies, antigen and RNA from eligible studies. Results: Of these, 3 studies reported co-circulation of all the 4 serotypes, while 2 separately reported co-circulation of DENV-1 &2 and DENV-1 to -3. All the antibody-based studies had significantly high heterogeneity (I2 >90%, P 0.05). The pooled prevalence of DENV IgM, IgG, RNA, NS1 and neutralizing antibodies were 16.8%, 34.7%, 7.7%, 7.7% and 0.7%, respectively. Southeast Nigeria had the highest pooled DENV-IgG seropositivity, 77.1%. Marital status, gender, educational level and occupation status, the proximity of residence to refuse dumpsite, frequent use of trousers and long sleeve shirts were significantly associated with DENV IgG seropositivity (P <0.05). Conclusion: Based on these findings, it can be inferred that Nigeria is hyperendemic for Dengue fever and needs concerted efforts to control its spread within and outside the country

Soft error tolerance using Horizontal-Vertical-Double-Bit diagonal parity method

The likelihood of soft errors increase with system complexity, reduction in operational voltages, exponential growth in transistors per chip, increases in clock frequencies and device shrinking. As the memory bit-cell area is condensed, single event upset that would have formerly despoiled only a single bit-cell are now proficient of upsetting multiple contiguous memory bit-cells per particle strike. While these error types are beyond the error handling capabilities of the frequently used error correction codes (ECCs) for single bit, the overhead associated with moving to more sophisticated codes for multi-bit errors is considered to be too costly. To address this issue, this paper presents a new approach to detect and correct multi-bit soft error by using Horizontal-Vertical-Double-Bit-Diagonal (HVDD) parity bits with a comparatively low overhead

Soft error tolerance using HVDQ (Horizontal-Vertical-Diagonal-Queen parity method)

The likelihood of soft errors increases with system complexity, reduction in operational voltages, exponential growth in transistors per chip, increases in clock frequencies and device shrinking. As the memory bit-cell area is condensed, single event upset that would have corrupted only a single bit-cell are now capable of upsetting multiple adjacent memory bit-cells per particle strike. Many of the errors occur when information is transmitted from one node to another node. Detection and correction of these errors is a must for many systems e.g. safety critical systems. To address this issue, a new approach is proposed in this paper to detect and correct multiple bit errors by using Horizontal-Vertical-Diagonal-Queen parity method (HVDQ). The experimental analysis shows the validation of the effectiveness of this approach by comparing its performance with existing approaches

A new algorithm to measure relevance among Web pages

This paper proposes a new algorithm to measure relevance among Web pages (RWP) using a hybrid method of hyperlink analysis and content analysis. Here we used a new approach to Web searching where the input to the search process is not a set of query terms, rather the URL of a page, and the output is a set of related Web pages. A related Web page is one that addresses the same topic as the original page. Here, the proposed algorithm first uses only the connectivity information in the Web (i.e., the links between pages) and then the content of pages. To evaluate the performance, the algorithm is compared with existing algorithms. Experimental results show that RWP outperforms existing algorithms to find relevant Web pages. RWP increases the search efficiency effectively and enhances the application area of Web related research

An Efficient Soft Error Tolerant Approach to Enhance Reliability of TCAM

Ternary Content Addressable Memory (TCAM) is a kind of extraordinary memory which is used to search operations in routers, firewalls, network address translators, and entire content in a single clock cycle. It is a special kind of memory which is used in highly reliable network applications. These systems require high reliability since a single error may interrupt any computation which may cause total system failure. However, TCAM is facing serious reliability challenges due to soft errors. The probability of soft errors in TCAM is increasing progressively due to alpha-particle, cosmic rays, high-vitality particles, and ionizing impacts of barometrical neutron. In order to minimize the risks of soft errors in TCAM, a new idea is proposed in this paper where the search key is constructed in a tricky way and the contents of the TCAM are ordered in a sequential pattern. The proposed method provides soft error tolerance with a low data overhead. Experimental study shows how the proposed method outperforms the existing method to tolerate soft error

Mitigating soft error risks through protecting critical variables and blocks

Smaller feature size, higher clock frequency and lower power consumption are of core concerns of today's nano-technology, which has been resulted by continuous downscaling of CMOS technologies. The resultant 'device shrinking' reduces the soft error tolerance of the VLSI circuits, as very little energy is needed to change their states. Safety critical systems are very sensitive to soft errors. A bit flip due to soft error can change the value of critical variable and consequently the system control flow can completely be changed which leads to system failure. To minimize soft error risks, a novel methodology is proposed to detect and recover from soft errors considering only 'critical code blocks' and 'critical variables' rather than considering all variables and/or blocks in the whole program. The proposed method shortens space and time overhead in comparison to existing dominant approaches

Population genetic analysis reveals a low level of genetic diversity of \u2018Candidatus Phytoplasma aurantifolia\u2019 causing witches\u2019 broom disease in lime.

Witches\u2019 broom disease of lime (WBDL) is a serious phytoplasma disease of acid lime in Oman, the UAE and Iran. Despite efforts to study it, no systemic study attempted to characterize the relationship among the associated phytoplasma, \u2018Candidatus Phytoplasma aurantifolia\u2019, from the three countries. This study utilized sequences of the 16S rRNA, imp and secA genes to characterize 57 strains collected from Oman (38), the UAE (9) and Iran (10). Phylogenetic analysis based on the 16S rRNA gene showed that the 57 strains shared 98.5\u2013100 % nucleotide similarity to each other and to strains of \u2018Ca. P. aurantifolia\u2019 available in GenBank. The level of genetic diversity was low based on the 16S rRNA (0-0.011), imp (0\u20130.002) and secA genes (0\u20130.015). The presence of low level of diversity among phytoplasma strains from Oman, the UAE and Iran can be explained by the movement of infected lime seedlings from one country to another through trading and exchange of infected plants. The study discusses implication of the findings on WBDL spread and management