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Sampling effort and its allocation in the Lincoln–Petersen experiment: A hierarchical approach
No full textCapture-recapture methods are widely used for estimating population sizes in ecological and epidemiological studies, yet the optimal allocation of sampling effort often remains underexplored. This study explores sampling efforts in a hierarchical framework that subdivides each capture occasion in a Lincoln–Petersen experiment into multiple sub-occasions, allowing for flexible resource allocation. When detection probabilities are equal across occasions, an even split minimizes variance; when probabilities differ, maximizing the joint detection probability is essential. A pseudo-Bayesian approach is also proposed to address scenarios with unknown catchabilities. Detailed simulation studies validate the theoretical findings and demonstrate the framework’s robustness. The resulting guidelines offer practical insights for designing more efficient capture-recapture experiments and improving population size estimates
The effectiveness of the long-lasting insecticidal nets in controlling malaria vector: a meta-analysis of experimental hut studies
No full textBackground: Malaria is a life-threatening, preventable, and curable vector borne disease caused by parasites that are transmitted to people through the bites of infected female Anopheles. The WHO Global Report 2010-2016 reported insecticide resistance in malaria. The main objective of this study is to determine the effectiveness of new generation Long-Lasting Insecticidal Nets (LLIN) compared to standard LLIN and untreated nets in terms of the mortality rate of adult female Anopheles gambiae.Methods:
A comprehensive review of the literature was published in three databases (PubMed, Ovid, EBSCO Host) since 2010. Publications were searched with keywords including malaria, long-lasting treated bed net, long lasting insecticide-treated bed net, LLIN, and experimental hut. The search has identified 60 articles. Based on the PRISMA flowchart, 10 articles are qualified for data collection and analysis. The gathered data was analysed using Review Manager.Results: Following meta-analysis between subgroups, a risk difference of 0.31 between standard LLINs versus untreated net (p<0.001, I²=100% 95% CI:0.01,0.60). A comparison of upgraded LLINs with the untreated net has shown a significant difference with a pooled risk difference of 0.54 favours upgraded LLINs (p<0.001, I²=100% 95% CI: 0.54,0.84). Comparison between upgraded LLINs versus standard gave an overall risk difference of 0.24 (p < 0.001, I² = 100%, 95% CI: 0.10–0.39).Conclusion: Upgraded LLINs significantly increase Anopheles mortality compared to standard LLINs and untreated nets, suggesting their potential for improved malaria control. Thus, using upgraded nets in the field and translating them into malaria preventive programs would help achieve the target and improve health outcomes for those living in endemic areas
Integrative approaches in remote sensing and GIS for assessing climate change impacts across Malaysian ecosystems and societies
No full textClimate change presents significant problems to Malaysia, impacting its ecology and socio-economic structure through modified precipitation patterns, heightened flooding, coastal erosion, and agricultural susceptibility. This review methodically evaluates the utilization of remote sensing (RS) and geographic information systems (GISs) in comprehending these effects, employing a systematic approach following the PRISMA protocol. Through the examination of peer-reviewed papers from 2010 to 2024, we underscore the progress in remote sensing (RS) and geographic information system (GIS) technologies and their contribution to improving the spatial analysis of climate change impacts. Our research indicates considerable regional variations in the effects of climate change, highlighting the need for customized adaptation and mitigation efforts. The research Illustrates how advancements In remote sensing (RS) and geographic information systems (GISs) have enhanced forecasting skills and real-time surveillance, offering essential insights into ecosystem susceptibilities and socio-economic threats. This analysis underscores the necessity for cohesive policy strategies that leverage remote sensing and geographic information system insights to tackle the complex difficulties posed by climate change in Malaysia while pushing for additional research on the amalgamation of artificial intelligence and big data analytics to bolster climate resilience
List of Scolytinae and Platypodinae (COLEOPTERA: Curculionidae) captured by ethanol-baited traps in a tropical rainforest in southern Sabah, Malaysia
No full textBark beetles (sensu lato) are found in the two subfamilies (Scolytinae and Platypodinae) of the family Curculionidae (Coleoptera) and ecologically diverse and economically important groups. The subfamily Platypodinae includes c. 1,500 species and almost all of these are ambrosia beetles (Peris et al., 2021). On the other hand, c. 6,100 species have been recorded for the subfamily Scolytinae (Cognato et al., 2021), which includes many feeding guilds such as phloem feeders (bark beetles (sensu stricto)), fungal feeders (ambrosia beetles), pith feeders, fruit and seed feeders, and other
Optimizing decentralized exam timetabling with a discrete whale optimization algorithm
No full text—In recent years, there has been increasing interest in intelligent optimization algorithms, such as the Whale Optimization Algorithm (WOA). Initially proposed for continuous domains, WOA mimics the hunting behavior of humpback whales and has been adapted for discrete domains through modifications. This paper presents a novel discrete Whale Optimization Algorithm approach, integrating the strengths of population-based and local-search algorithms for addressing the examination timetabling problem, a significant challenge many educational institutions face. This problem remains an active area of research and, to the authors' knowledge, has not been adequately addressed by the WOA algorithm. The method was evaluated using real-world data from the first semester of 2023/2024 for faculties at the Universiti of Sarawak, Malaysia. The problem incorporates standard and faculty-specified constraints commonly encountered in realworld scenarios, accommodating online and physical assessments. These constraints include resource utilization, exam spread, splitting exams for shared and non-shared rooms, and period preferences, effectively addressing the diverse requirements of faculties. The proposed method begins by generating an initial solution using a constructive heuristic. Then, several search methods were employed for comparison during the improvement phase, including three Variable Neighborhood Descent (VND) variations and two modified WOA algorithms employing five distinct neighborhoods. These methods have been rigorously tested and compared against proprietary heuristicbased software and manual methods. Among all approaches, the WOA integrated with the iterative threshold-based VND approach outperforms the others. Furthermore, a comparative analysis of the current decentralized approach, decentralized with re-optimization, and centralized approaches underscores the advantages of centralized scheduling in enhancing performance and adaptability
“Wairon and Waimansusu”: war boat and trade boat of the Biak people in Papua Indonesia
No full textThis article discusses the traditional boat technology of the Wairon and Waimansusu, which were the main means of transport for the Biak tribe in shipping and trade on the north coast of Papua during the 8th to 19th centuries. Although Papua has various types of traditional boats with their own uniqueness, only a few are able to sail as far as the Maluku Islands. For the Biak Tribe, the Wairon and Waimansusu boats are not only functional, but also have artistic and symbolic value in the maritime history of the eastern region of the archipelago. Using a historical and ethnographic approach, this article reconstructs the manufacturing technology, cruising ability and carrying capacity of both types of boats in the context of voyaging, trading and hunting. Today, the manufacture of Wairon and Waimansusu is increasingly rare, despite their high cultural value and great potential to support the development of marine tourism in Cenderawasih Bay, Papua-Indonesia
Comparative analysis of microbial diversity in various kombucha starter cultures in Malaysia using the random amplified polymorphic DNA (RAPD) approach
No full textKombucha is sweetened black tea fermented with symbiotic culture of bacteria and yeasts (SCOBY) and has been widely consumed for its purported health benefits. The microbial consortium in kombucha is dominated by yeasts such as Brettanomyces sp. and Zygosaccharomyces sp., as well as acetic acid bacteria (AAB), Komagataeibacter sp. and Acetobacter sp. However, the source of SCOBY and substrates used may affect the microbial diversity as well as the biochemical, and flavour of the kombucha. Identifying the microbial population is important as the use of undefined starter cultures may lead to variable metabolite production and increase the risk of food pathogen contamination which can pose harm to human health. This study aims to isolate the microbes from kombucha in Malaysia for the future development of a new starter culture with specific species for the safe consumption of kombucha. Briefly, a total of 100 colonies were isolated from nine kombucha starter cultures with selective culture plates. Differences in colony morphology were observed based on their colours, surface texture, elevation, and margin. Their phenotypic morphology and genetic diversity were screened using microscopic examination, coupled with a catalase test and random amplified polymorphic DNA (RAPD), respectively. Based on the data, 51% of the isolates showed yeasts morphology under microscopic examination, while the rest were bacteria. Additionally, 55.79% of the isolates showed distinct banding profile patterns in the RAPD assessments. In conclusion, the data of this study shows that there is a diverse microbial consortium in different starter cultures of kombucha from Malaysia, mainly predominated by Gram-negative AAB and Gram-positive yeasts. Identification at the species level is to be conducted in the future. By understanding the microbiota diversity in kombucha, it contributes to the development and production of a safe functional drink
Inflation threshold effects on stock prices: Evidence from the plantation sector in Malaysia
No full textThis study aims to examine the threshold effect of inflation on stock prices in the Malaysian plantation sector. This study used earnings per share (EPS) and return on equity (ROE) as proxies for microeconomic variables, and inflation (INF which proxies for the consumer price index) as a proxy for macroeconomic variables. A panel dataset covering 32 listed companies in the plantation sector from 2008Q3 to 2023Q3 is used. The results of threshold analysis show that inflation has a nonlinear effect, with a threshold value of 4.6128%. This implies that when inflation crosses this value, it significantly alters the outcome of stock prices. Inflation consistently has a negative effect on stock prices across both regimes, although the impact slightly decreases under higher inflation. Higher inflation will increase the detrimental effects of ROE and reverses the significance effect of EPS and DTE to insignificant, while enhancing the positive contributions of revenue and operating cash flow
Analyzing the influence of macroeconomic variables on tourism receipts in OIC countries: A quantile analysis approach across varying income levels
No full textThis study examines the heterogeneous effects of macroeconomic variables on tourism receipts across income tiers in Organization of Islamic Cooperation (OIC) countries, addressing a critical gap in tourism economics literature. Employing a panel quantile regression approach on data from 34 OIC countries (1995–2020), the research analyzes how exchange rates, income per capita, inflation, and trade openness differentially influence tourism receipts at lower, middle, and upper quantiles of tourism spending. The methodology leverages quantile regression for panel data (QRPD) to account for non-linear relationships and income-level heterogeneity, offering a nuanced alternative to traditional linear models. Key findings reveal significant income-tiered disparities. Exchange rate depreciation enhances tourism receipts in most contexts, except in upper-middleincome countries, where volatility signals instability. Income per capita exhibits positive yet inelastic effects in low- and lower-middle-income nations, but adverse impacts in high-income countries, suggesting market saturation. Inflation erodes receipts in low-income economies but stimulates demand in high-income OIC states, reflecting divergent tourist price sensitivities. Trade openness consistently suppresses tourism across quantiles, with high-income countries experiencing the steepest declines. These results challenge the universality of the Tourism-Led Growth Hypothesis, emphasizing context-specific dynamics. Policy recommendations advocate for income-tiered strategies: low-income countries should prioritize exchange rate stabilization, inflation control, and infrastructure investments via Islamic finance instruments, while high-income nations must pivot to premium niches like halal and cultural tourism. Regional cooperation through unified visa policies and OICwide halal certification standards is critical to harnessing collective tourism potential. Policymakers are urged to balance trade liberalization with targeted tourism-sector incentives to mitigate resource diversion. By aligning interventions with macroeconomic realities, OIC countries can transform tourism into an engine of equitable growth, advancing Sustainable Development Goals (SDGs) on economic diversification and inclusive employment
Fresh and hardened properties of alkali-activated POFA-GGBFS pastes cured in ambient temperature – An initial mix design
Get PDFWeak soils are characterised by their high compressibility and low shear strength, which requires stabilisation to improve their compaction and strength characteristics before being used for construction projects. Recent trends in soil stabilisation show an increased interest in the application of waste-derived geopolymers as low-carbon materials to address the carbon emission problem related to cement production. This paper presents the preliminary findings of using Palm Oil Fuel Ash (POFA) and Ground Granulated Blast Furnace Slag (GGBFS) binary blends as geopolymer precursor materials. These binary waste material blends were activated using alkaline solutions, namely Sodium Hydroxide (NH) and Sodium Silicate (NS), to synthesise geopolymers at ambient temperatures. Three main factors were considered for the optimisation of the geopolymer mix design, as recommended by past research: alkali equivalent (8-11.5%), activator modulus (0-0.7), and slag replacement (fixed at 30%). Alkali equivalent and activator modulus parameters were varied and tested to establish its initial and final setting times, workability and strength properties, while the slag replacement percentage was set at 30%. This study aimed to determine the most influential parameters to produce the geopolymer material with the highest compressive strength and satisfactory setting times and workability. Single-source alkali activators (NH only) used on POFA-GGBFS produced specimens with smaller flow diameters, longer initial and final setting times, and lower compressive strength than specimens activated with NH and NS. Geopolymer specimens synthesised with NH and NS produce stiffer compounds possessing higher compressive strength values and explosive-type failure modes due to their higher silica content. At ambient temperatures, TM-Mix 2 (7% alkali equivalent and 0.7 activator modulus) produced the highest compressive strength value of 67.3 MPa at 28 days curing, flow diameter of 227 mm, with the initial and final setting time of 25 minutes and 45 minutes, respectively. Consequently, the results show that the preliminary POFA-GGBFS geopolymer mix design could produce sustainably sourced geopolymer compounds with adequate strength and acceptable setting time and workability. This study is part of a current investigation to further optimise the POFA-GGBFS mix design for the purpose of weak soil stabilisation