Ruhuna Journal of Science is the official journal of Faculty of Science, University of Ruhuna, Sri Lanka. Official abbreviation: Ruhuna J. Sci. (Online) eISSN: 2536-8400 (Print version/ before 2014) ISSN: 1800-279X https://www.rjs.ruh.ac.lk
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List of Reviewers- Ruhuna J Science. Vol 14 - 2023
Microbial solutions for plastic pollutants: Caprolactam, Polyvinyl alcohol, and surgical face masks
Caprolactam and polyvinyl alcohol (PVA) are plastic pollutants that in excess concentrations affect the environment adversely. The purpose of this study was to identify the microorganisms with the potential to break down biodegradable polyvinyl alcohol synthetic plastic polymer caprolactam, and face masks. Caprolactam and PVA-degrading bacteria were isolated from the soil. The identification of the isolate was done using morphological, biochemical and 16S rRNA sequencing and identified as Pseudomonas aeruginosa. Colorimetric and reverse-phase high-performance liquid chromatography analysis revealed the degradation of 61 and 96 % caprolactam (1%) and PVA (0.1%) respectively by the isolate. The degradative product of caprolactam and polyvinyl alcohol was identified as adipic acid and fumaric acid based on the mass spectroscopic analysis. Field emission scanning electron microscopy of the control and bacterial-treated face mask was carried out to check the degradation potential of the strain. Microbial face mask degradation showed 97.89 % reduction in the diameter of fibers, which proved the potential use of Pseudomonas aeruginosa in the remediation of bioplastic, synthetic and microplastic polluted areas. Keywords: Caprolactam, face mask, microplastic, polyvinyl alcohol, Pseudomonas
Cytogenotoxicity and safe doses of Azadirachta indica L. (Neem tree) leaf extract obtained in Birnin Kebbi, Nigeria
Azadirachta indica (neem tree) is used to treat diseases in Nigeria, however, scarcity of documented information on the plant's toxicity exists in the country. Toxicity evaluation of medicinal plants in relation to geographical location is essential, as toxicity may vary due to differences in pollutants and environmental factors. This study assessed the phytochemical composition, heavy metal content, cytotoxic potential, and safe doses of methanolic leaf extracts of A. indica obtained from Birnin Kebbi, Nigeria. Twenty-one Allium cepa bulbs were divided equally into seven groups. The negative control (Group 1) and positive control (Group 2) bulbs were grown for five days over beakers containing distilled water and formaldehyde, respectively. Test groups (Groups 3–7) were grown over beakers containing A. indica extract solutions at concentrations of 0.25, 0.5, 1.0, 2.0, and 4.0 g, respectively. Phytochemical analysis revealed abundant flavonoids, phenols, and saponins, moderate levels of tannins, and trace amounts of quinones, cardiac glycosides, and terpenoids. Heavy metal analysis showed the presence of copper (3.8 mg/kg), lead (0.12 mg/kg), and cadmium (0.04 mg/kg), all of which exceeded the permissible limits established by WHO. Except for the 0.25 g group, the test groups exhibited dose-dependent (p ≤ 0.05) cytogenetic effects, including reduced root growth and mitotic index. Chromosomal abnormalities such as sticky, bridged, vagrant, laggard, and fragmented chromosomes were also observed. These findings suggest that A. indica may be safe at low concentrations but exhibits toxic effects at higher concentrations. The results provide a valuable baseline for further investigations into the plant's safety. Keywords: Azadirachta indica (neem tree), lead, mitotic index, saponins, vagrant chromosomes.
Effect of sub-lethal concentrations of urea on the development of endemic arboreal tree frog, Polypedatus cruciger (Amphibia: Racophoridae)
Amphibian decline has become a worldwide problem today. Climate change, UV radiation, diseases, contaminants, and fertilizers could be considered as the main reasons. The present study was carried out to investigate the effect of urea on the survival, growth, behaviour and morphology of the endemic arboreal tree frog Polypedatus cruciger (Anura: Ranidae). First, the Lethal Concentration 50 (LC50) of urea on 10 days old post-hatched tadpoles was determined. After the estimation of LC50, the tadpoles were exposed to three sub-lethal concentrations of urea, namely, 7.0 g/L, 7.5 g/L and 8.2 g/L. The effects were investigated from the age of 10 days until they became adults. The impact of sub-lethal concentrations of urea for the survivals, snout-vent length and weight showed significant differences (p<0.05), and a strong negative correlation existed when compared to the control. The tadpoles were very sensitive to urea as they showed several behavioural changes such as reduction in feeding, growth retardation and inability to grow up to the adult stage. The observed external morphological changes under the laboratory conditions included edema, abdominal lesions, colour change, tail deformations and rupturing of tadpoles. The impact of urea on the amphibians in the field may be severe due to the synergistic effects of different pollutants. This may adversely affect amphibians, as their life stages are associated with the agroecosystems and may cause a severe decline in amphibian fauna in Sri Lanka. Keywords: Amphibian fauna, Life stages, Pollutants, Synergistic effect, Tadpoles
Awareness and usage of food labelling in purchasing pattern of pre-packed foods in Ampara District, Sri Lanka
The awareness and attitude of the food label reading are related to the consumer's healthier food choices. The objective of this study was to evaluate the level of awareness and reading habits of food labels, and how these affect the consumers' food choices in Ampara district, Sri Lanka. The questionnaire study was employed to acquire data related to the socio-demographic details, degree of food label usage, awareness, and utilization of food labelling and nutrient labelling. There were 369 consumers in the Ampara district who participated in the questionnaire survey selected based on convenient sampling. The collected data were interpreted using descriptive statistics and a multinominal regression model. According to the results, most consumers (73.5%) bought the packet forms of pre-packed foods, and 52.4% preferred the box forms of pre-packed foods. The consumers (97.2%) read the food labels before purchasing, and most of them checked the label on every occasion (73.2%), followed by the few who occasionally checked (23.8%). Further, certain major tags were observed during the purchasing, including expiry/manufactured dates, price, ingredients, and brand in the packing. In addition, 56.7% of the consumers did not know about the traffic light labelling system. Consumers generally preferred products with moderate levels of sugar, salt, and fat. In conclusion, the analysis highlighted that socio-demographic factors played a significant role (p<0.05) in influencing the developed multinomial logistic model. These factors, including age, income, and education level, were found to shape both the understanding of information presented on food labels and the preferences for pre-packaged food products. The study revealed that most consumers in the Ampara district, Sri Lanka are aware of the importance of reading food labels before making purchases. Keywords: Awareness survey, Consumer knowledge, Food labels, Pre-packed food, Traffic light labelling.
Productivity income nexus in Nigeria: Empirical lessons from COVID-19 lockdown
In an attempt to control the coronavirus, governments worldwide imposed lockdown measures, yet the consequences on productivity income for microeconomic policy were not clearly known, especially in developing countries. This study examined the effect of the COVID-19 pandemic on the productivity and income of Nigerian households under strict lockdown during 2020 using a cross-section based online survey. Participants were sampled from Nigeria’s geopolitical zones via a snowball sampling method. A total of 467 household data were utilized for the analysis. Descriptive statistics, hierarchical and stepwise regression models were applied to the data. Results show that the COVID-19 lockdown negatively affected productivity by 71.3% and income by 58.2%. Younger populations were more affected (β = -0.159, p<0.05) as well as people with marital responsibilities (β = 0.617, p<0.05). The global pandemic had negative consequences on the productivity of young populations. The reducing effect of the pandemic on income had the potential to add a greater burden to the household welfare of family people. This study provides an empirical insight into the microeconomic effect of a pandemic on households in developing nations. Keywords: Cross-sectional study, global pandemic, household income.
Quantification of nitrogen leaching losses by paddy cultivation under controlled and continual runoff conditions
In Asia, paddy is an important food crop that requires a high level of nitrogen, which is provided by straight chemical fertilizers that contribute a single nutrient, mainly urea. A study was conducted to quantify the leaching loss of nitrogen (as NO3--N) under two water management practices: controlled runoff and continual runoff in paddy cultivation at Low Country Intermediate Zone, Sri Lanka from 2015 to 2016 for four consecutive cropping seasons. Urea (N 46%) was applied as a sole source of Nitrogen at the rate of 225 kg ha-1. A randomized complete block design was employed with triplicates by two factors and two levels (cropping seasons; Yala, Maha, gradients; upper, lower). Lysimeters were arranged to collect leached water. The leachate from the study plots was collected weekly throughout the cropping period and the total amount of leached NO3--N for each cropping season was quantified. The leaching losses of NO3--N accounted under controlled runoff and continual runoff conditions were 8.6 kg ha-1 and 3.0 kg ha-1 respectively throughout the cropping period. It contributed to 8% and 3% of Nitrogen out of the total amount of applied N fertilizers in the same order. The water management practices and gradient effects were significant with respect to nitrogen leaching losses from paddy fields while cropping season had no effect on nitrogen leaching. A significant amount of nitrogen leaching losses could occur under the root zone, even though a controlled runoff situation posing possible threats of surface and groundwater pollution. Keywords: Nitrogen leaching, chemical fertilizer, paddy, rice.
Acoustic and visual observations of Sperm Whales, Physeter macrocephalus, off the Southeast Coast of Sri Lanka, April 2013
An opportunistic study was carried out from a 113’ motor-sailing vessel along the southeast coast of Sri Lanka from April 11 to 19, 2013. Passive acoustic monitoring allowed pods of sperm whales (Physeter macrocephalus) to be detected and tracked before being sighted. Key observations included sightings of whales along the 1000 m drop-off, repeated breaching of whales on two separate occasions within 50 m of a driftnet, and the presence of a single bull male with mating-related behaviour and jaw-clapping. These observations and other visual observations during the ship’s voyages indicate that sperm whales are located in Sri Lanka waters for feeding, breeding and calving. Keywords: Bull, Calves, Clang, Driftnet, Jaw Clap
Machine learning approaches for forecasting inflation: empirical evidence from Sri Lanka
The aim of this study is to forecast the inflation rate using supervised machine learning models (SMLM). While SMLMs are widely used in various fields, they have also been widely applied to forecast inflation rates. Therefore, the main objective of this study is to identify the best model for forecasting inflation among four different SMLMs: LASSO regression (LR), Bayesian Ridge Regression (BRR), Support Vector Machine Regression (SVR), and Random Forest Regression (RFR) models. To achieve this objective, two different types of cross-validation techniques were used: K-fold cross-validation method (KCV) and walk forward validation (WFV) methods. These techniques were used to estimate the parameters and hyper-parameters for each machine learning model with the aid of root mean square error. The mean absolute percentage error (MAPE) was used to compare the performance of the different SMLMs. Empirical evidence from Sri Lanka between 1988 and 2021 was used to test the performance of the SMLMs in forecasting inflation rates. The results show that the LR model with walk forward validation is the best method for forecasting the future inflation rate of Sri Lanka based on the MAPE value. Overall, this study demonstrates the effectiveness of SMLMs in forecasting inflation rates under the critical conditions and highlights the importance of employing appropriate cross-validation techniques when using these SMLM models. The findings of this study can provide valuable insights for policymakers, investors, and researchers who are interested in forecasting inflation rates. Keywords: Cross-Validation, Hyper-parameter, Inflation Forecasting, Machine Learning Models.
Utilization of elephant foot yam (Amorphophallus paeoniifolius) and Lasia stem (Lasia spinosa) replacers in burger patties
Many meat-based processed foods have been developed with plant-based fat replacers due to the adverse effects of cholesterol and unsaturated fatty acids in meat. Many underutilized plants have the potential to be used as fat replacers in processed meat-based products. In this study, different amounts of elephant foot yam (Amorphophallus paeoniifolius) flour and lasia (Lasia spinosa) stem flour were used as replacements for the chicken burger patty. The treatments were developed with the composition of elephant foot yam flour, lasia stem flour and chicken meat as T1 (30 %, 30 %, 40%), T2 (25 %, 25 %, 50 %), T3 (25 %, 15 %, 60 %), T4 (15 %, 25 %, 60 %) respectively, and T5 (100 % chicken) as a control treatment. The physico-chemical, cooking, and sensorial properties of the triplicated samples were then compared to those of a control group made with 100% chicken. Cooking properties such as cooking loss, cooking yield, water holding capacity, fat retention, moisture retention, and shrinkage have shown significant differences (p<0.05) among the treatments. Overall, 25% elephant foot yam flour and 15% lasia stem flour incorporated patties have shown optimum values for water holding capacity, cooking yield, fat retention, moisture retention, and cooking loss compared to control except shrinkage. The proximate analysis, such as moisture content, protein, fat, fiber content, and ash content had significant differences (p<0.05) among the treatments and 25 % elephant foot yam flour and 15 % lasia stem flour incorporated patties showed favorable values. Compared to the control, patties incorporated with elephant foot yam and lasia stem flour replacements have shown lower fat content and higher fiber content. However, the sensory attributes of the replaced burger patties were not different compared to 100% chicken meat burger patty except for colour and taste. Keywords: Burger patties, meat-replacers, proximate analysis, sensory attributes.
Open vehicle routing problem with moving shipments at the cross-docking terminal
In this study, one of the internal operations at the Cross-docking Terminal (CDT), moving shipments (MS) from receiving doors to shipping doors of CDT is integrated with Open Vehicle Routing Problem (OVRP) and the problem is indicated here as OVRPCD-MS. As an additional feature, asymmetric distance between any two customers is assigned by incorporating a characteristic of one-way routes between cities in real-life transportation. The objective is to minimize the total transportation cost which incurs travelling cost between customers, service cost at customer points, service cost at the receiving and shipping doors of CDT, cost of moving shipments inside the CDT and finally the cost of hiring fleets of vehicles. To solve the OVRPCD-MS problem, a Mixed Integer Linear Programming (MILP) model is developed. The programming models are implemented in LINGO (version 18) optimization software. Branch and Bound algorithm is employed to solve ten small-scale instances generated randomly. The applicability of the proposed MILP model is observed. The required fleets of vehicles to be hired and run time to reach the optimal solution are determined. The study revealed that the average run time is exponential for small-scale instances. Thus, it can be concluded that this proposed model can be used for last-time planning for small-scale instances. Also, the combinatorial nature of the vehicle routing problem makes OVRPCD-MS as NP-hard. Therefore, this study recommends that heuristic or meta-heuristic methods are more appropriate for the large-scale instances of OVRPCD-MS to reach near-optimum solutions. Keywords: Cross-docking, Moving shipments, Open vehicle routing.
Paleoenvironment and Diagenetic Aspects of the Limestone (Gboko Formation) around Igumale, Middle Benue Trough, Nigeria: Evidence from petrography
Limestones around Igumale-1 and Igumale-2 wells, Middle Benue Trough were petrographically studied in detail with a view to determine their paleo-depositional environment and diagenetic history. Petrographic examination of the limestone shows that the limestone comprised monocrystalline quartz, ferroan calcite (3% -15%), pelloids (3% -20%),ooids (7% -10%), micrite (33% - 48%) and sparites (10% -50%). Fossil fragments consisting of foraminifera and gastropods (17% -57%), and suggest subtidal to shallow marine environment. Four sedimentary facies (oobiosparite, biosparite, biopelmicrite, and biomicrite) were recorded and characterized by moldic and vuggy porosity. This study has provided a petrographic synopsis of the limestone for further considerations, and may have an impact on both exploration and development of the limestone. Keywords: Diagenetic; limestone; Gboko Formation; Benue; trough; marine; moldic; poor; perfomance
Qualitative mineralogical analysis of Barracuda exploration well in the offshore Mannar Basin (the Indian Ocean) using FTIR and XRD techniques
The Mannar Basin plays a vital role in petroleum exploration in Sri Lanka, and its Barracuda exploration well was drilled up to 4206 m in depth. The objective of the current study is to identify mineralogy using Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses. The FTIR and XRD analyses confirm the presence of quartz, feldspar, clay minerals (e.g. kaolinite, montmorillonite), calcite, and hematite in all marlstone and mudstones samples. These sedimentary rocks can be identified as potential petroleum source rocks in the Mannar Basin. Quartz, carbonate, and hematite cementations are directly reduced porosity and permeability, and thus primary migration of hydrocarbons from potential source rocks. Clay minerals act as a seal for hydrocarbon migrations in the Mannar Basin. A variety of dominant clay mineral assemblages allows the reconstruction of several paleo climatic chronozones in warm/wet and arid climates. In contrast, feldspar dissolution promotes the primary migration of hydrocarbon from potential petroleum source rocks. Consequently, this study concluded that common minerals such as quartz, carbonate, and hematite are associated with the trapping and binding processes of hydrocarbons. Keywords: Cementation, clay mineral, petroleum source rock, primary hydrocarbon migration
Meteorological data prediction over selected stations in Sub-Sahara Africa: Leveraging on Machine Learning Algorithm
This study investigated selected meteorological data prediction leveraging on a Machine Learning Algorithm Approach over five selected stations in Nigeria. The algorithm of Machine Learning was explored using weather parameters such as temperature, wind speed, wind direction and relative humidity to predict the rainfall rate. In the results, five Gaussian models (i.e., Rational Quadratic, Squared Exponential, Matern 5/2, Exponential and Optimized GPR) revealed different Root Mean Square Error (RMSE), Mean Square Error (MSE), and Mean Absolute Error (MAE) with prediction speeds ranging from 15000 to 26000 and the training time included 7.936, 1.8923, 2.3701, 3.267 and 282.19, respectively. The predicted response as against the true response for the two models shows a linear graph passing through the origin which confirmed a perfect regression model, where all the points lie on a diagonal line. Therefore, the relationship between MSE, MAE and RMSE for different models revealed that the optimized GPR has a better performance as compared to others. More so, visualizing the relationship between the output variable (rainfall) and each input variable reveals that some input variables (relative humidity, rainfall, pressure, wind speed and direction) have a strong correlation with the output variable (rainfall), with others having a noisy relationship which is not very clear. Keywords: Atmospheric Physics, Gaussian Model, Machine Learning, meteorological data, statistical model.
Diversity of Ferns and Lycophytes in the Mt. Malambo, Southern Philippines
This research was carried out to study the diversity and assess the conservation status and endemism of ferns and lycophytes in the Mt. Malambo, Datu Salumay, Southern Philippines. Repeated transect walks were done with 20 sampling plots delineated on the site. Specimens were collected, identified, and assessed for their conservation status and endemism. Data gathered were analyzed employing the Shannon-Weiner Index. The inventory revealed 215 species (202 species of ferns and 13 species of lycophytes) belonging to 74 genera and 23 families. Polypodiaceae, Aspleniaceae, Hymenophyllaceae, and Pteridaceae were the species-rich families collected. Asplenium nidus L., Pneumatopteris costata (Brackenr.) Holttum, and Asplenium thunbergii Kunze obtained the highest species importance values. Mt. Malambo has a diversity value of H’=1.83 which is higher compared to other mountains in Mindanao. This study reports 20 Philippine endemic and 19 threatened species of ferns and lycophytes in the area. Of these, one is critically endangered, 11 are endangered, five are vulnerable, and two are other threatened species. The presence of many threatened and endemic species in the area implies that high priority should be addressed in protecting and conserving these species of ferns and lycophytes in Mt. Malambo. Keywords: Diversity assessment, inventory, montane forest, pteridophytes, threatened species
Impact of freezing methods on the physicochemical and sensory qualities of frozen carrot (Daucus carota) (Cape Market variety) dices
Carrots (Daucus carota) are root vegetables that contain carotenoids, flavonoids, polyacetylenes, vitamins, and minerals. They are high in antioxidants, anticarcinogens, and immune enhancers making them excellent for the eyes. Carrots suffer from significant postharvest losses in Sri Lanka due to their perishable nature, as well as rejections due to their odd morphologies. Even though demand for carrot is high all around the country, losses are unavoidable. Freezing techniques play a vital role in maintaining freshness and avoiding deterioration simultaneously. The goal of the present study was to find the best freezing method among blast freezing (-30 °C) and conventional (-18 °C) freezing circumstances for a superior quality of frozen carrot dice. Blanched (90 °C for 3min) carrot dice (Cape market variety) were frozen and thawed, then physicochemical parameters like drip loss (%), pH and colour, and other aspects including length ratio, hardness and cutting shearing strength and sensory parameters like colour, odour, texture and overall quality changes during freezing were analyzed. The blast frozen-thawed carrot dices showed the best quality of fresh colour, 8.50 ± 2.83 of colour change, 5.573 ± 0.555 % of drip loss, 0.0333 ± 0.007 length ratio, 21.53 N ± 3.78 hardness, 0.1366 J ± 0.0361 cutting and shearing strength, and 5.6867 ± 0.01 pH than conventional frozen-thawed dices. Mann Whitney U test resulted that blast frozen carrot dices had significantly (p<0.05) higher consumer preference than conventionally treated samples during the sensory analysis. Keywords: Blast freezing, carrot deterioration, conventional freezing, frozen carrots, quality of carrots.
Temporal variation in flower visiting insects of Calotropis gigantea in the Southern Province of Sri Lanka
Calotropis gigantea (Giant milkweed) is a medicinal plant native to a few Asian countries including Sri Lanka. However, the plant is considered invasive in countries such as Australia, the USA and Brazil. It produces flowers throughout the year leading to massive fruit production, and pollination may directly influence the reproductive output of the plant. Knowledge of the insect flower visitors of C. gigantea is essential to cultivate them for experimental purposes, to conserve them in their native range, or to eradicate them in their introduced range. Though the plant is commonly distributed in Sri Lanka, information on its flower visitors is rare. Therefore, the objective of this study was to identify the flower-visiting insects of C. gigantea and their temporal abundance. Monthly field visits were made to eleven sites in Southern Province from August 2015 to August 2016. During sampling, flower visitor species, their abundance, and the number of Calotropis fruits in the selected plants were recorded. Danaus chrysippus, Xylocopa caerulea, Xylocopa fenestrate and Apis cerana were identified as flower visitors of C. gigantea. The most common was Xylocopa spp. and it was recorded in all sites, and during all studied months while Danaus chrysippus was uncommon. The abundance of Xylocopa spp. had a positive correlation with the abundance of C. gigantea fruits (r = 0.094, p<0.001) suggesting its likely role in the pollination of the latter. Monthly rainfall had a strong correlation (r = 0.806, p = 0.002) with the flower-visiting insect abundance of C. gigantea in the Matara district. Mean flower-visitor abundance was comparatively high in sites having the least anthropological impact. Keywords: Calotropis gigantea, flower visitors, Sri Lanka
Process optimization for the development of easy-to-cook jackfruit bulbs
Overproduction of jackfruit (Artocarpus heterophyllus) in harvesting seasons and its short post-harvest shelf life make it an underutilized fruit species. The present study was conducted to analyze the feasibility of preparing processed jackfruit products to enhance utilization and reduce wastage. Jackfruit bulbs were cut into 4.5 cm ± 0.5 cm in length and 0.5 cm ± 0.3 cm in width pieces. The two-factor factorial technique was used as the experimental design when developing the products. As factors, the freezing operation and dipping treatment were considered. Hot water extracts of A. heterophyllus leaves and Trachyspermum ammi leaves were used as two dipping treatments and sensory evaluation tests were carried out to determine which dipping treatment is better. T. ammi dipping treatment had better sensory acceptance, and hence continued as the selected dipping method. The effect of freezing (-18 °C for 12 h), pre-cooking time, and rehydration on cooking time was also investigated. Frozen and non-dipped jackfruit bulb pieces had the highest sensory acceptance, hence its proximate composition, DPPH, total phenolic acid, and colourimetric values were determined. Moisture, ash, fat, crude protein and carbohydrate content of the frozen non-dipped jackfruit bulbs were 8.08 ± 0.28 %, 0.88 ± 0.01 %, 0.31 ± 0.03 %, 3.93 ± 0.06 %, 81.09 ± 0.54 % respectively. The colourimetric values (L*, a*, and b*) of the frozen non-dipped jackfruit bulbs were 79.40 ± 0.61, 1.87 ± 0.35, 25.43 ± 1.33, 25.50 ± 1.35 respectively. The results revealed that the freezing operation significantly (P<0.05) reduce the cooking time of jackfruit bulbs. Based on the sensory evaluation results, jackfruit bulbs that were frozen without dipping the T. ammi leaf extract were identified as having the best sensory acceptability. The final processed product possesses a good nutritional profile concerning the ash, fat, crude protein, carbohydrate, mineral content, DPPH and total phenolic acid content. Keywords: Easy to cook food, jackfruit bulb, Proximate composition.
Guard hair micro-morphology of four non-human primates in Shasha Forest Reserve, Osun State, Nigeria
Mammalian guard hairs have been used for their identification and have been proved useful in wildlife population surveys and trafficking. The qualitative and quantitative features of the dorsal guard hairs of four non-human primates (NHPs) from Shasha Forest Reserve were studied using standard procedures to determine their differences. The NHPs were mona (MM), putty-nosed (PNM), and white-throated (WTM) monkeys, and red-capped mangabey (RCM). The qualitative features determined were medulla pattern, and structure, scale margin distance and type, and scale pattern. The quantitative values studied were scale length and width, shaft diameter (μm), medulla diameter, and medulla index and fraction. Continuous medulla pattern was the only qualitative feature common to all the species. The MM hair had the highest recorded values for all morphological characteristics except shaft diameter and scale width in which PNM had the highest value of 323.00 ± 58.37 and 630.55 ± 213.95μm respectively. The medullary diameter, index and fraction, and shaft diameter were highly significant (P<0.001) among all the species. Post-hoc comparison showed that the medullary diameter, index, and fraction of hairs of the MM was significantly different (Pâ‰¤0.001) from the other three NPHs. The shaft diameter of the MM was also significantly different from that of the PNM (Pâ‰¤0.001), and WTM (Pâ‰¤0.004). The scale width of RCM differed from PNM (Pâ‰¤0.01), and WTM (Pâ‰¤0.05). These empirically established morphological differences in guard hairs of the four NHPs in SFR would be useful in verifying their habitat occupancy and forensic evidence in case of illegal trafficking. Keywords. Dorsal hair, medulla hair pattern, mona monkey, non-invasive studies, qualitative hair features.
Zooplankton community structure of a tropical lake in a Northcentral State, Nigeria
One of the biological components that play a vital role in the ecological integrity of an aquatic ecosystem is zooplankton. These organisms are good indicators of stressors, especially anthropogenic stressors in their environment. Thus, there is a need to study the diversity in a diversified freshwater lake (Dangana Lake) in order to provide baseline information and knowledge on the status of the lake for proper and adequate water preservation and conservation. In addition to the zooplankton structure determination, the study also examined the physicochemical parameters of the Lake. Three sampling sites were identified with distinct characteristics where water and zooplankton samples were collected for physicochemical analyses and biotic identification using standard protocols. Sampling was conducted for a duration of eight months. The monitored physicochemical parameters, i.e., temperature, dissolved oxygen (DO), biochemical oxygen demand (BOD5) and pH revealed no significant difference (p>0.05) among sampling sites. However, significance (p<0.05) amongst sampling sites was recorded in electrical conductivity, nitrate and phosphate. Seasonally, there was a significant difference (p<0.05) among sampling months in all the monitored parameters. A total of ten species of zooplankton were recorded with four species each of rotifera and copepoda and two species of cladocera. The order of abundance of zooplankton population was rotifera (56.39%), copepoda (29.18%) and cladocera (14.42%). Zooplankton population was significantly (p<0.05) higher during the dry season than in the rainy season. The Canonical correspondence analysis (CCA) revealed a strong correlation between the zooplankton and physicochemical parameters. Ipso-facto, the lake exhibited spatiotemporal changes in zooplankton composition and physicochemical parameters during the sampling period. Keywords: Anthropogenic activities, Dangana Lake, Physicochemical parameters, Zooplankton
List of Reviewers- 2022 - Ruhuna Journal of Science
Attitudes and perceptions of farmers on the African grey parrot in Oba Hills National Park, Osun State, Nigeria
This study is focused on people’s perceptions and attitudes on the population decline of African Grey Parrots (Psittacus erithacus) in Osun state, Nigeria. Data was collected through a structured questionnaire. The population of the study area comprises 234 farmers from communities in the study area. Data were analyzed using descriptive statistics, T-test, Pearson Correlation, and Chi-square test. The results revealed that 78% of the respondents were male, while 22% were female. Majority (51%) of the farmers were between the age group of 41-59 years, Christians (54%), indigenes (76%), and Nigerian (69%). As revealed from the study, 77.5% of the farmers were familiar with the African Grey Parrot (Psittacus erithacus). The farmers showed great knowledge of the bird and the ecosystem services rendered, thus they have a positive perception and attitude about African Grey Parrot conservation. The study recommended that the bird conservation club be initiated by forest management which should include youths, adults, and school teachers in the area in order to enlist farmers in the bird conservation program. Keywords: Conservation, Ecosystem services, Knowledge and Perception
Nutritive and sensory value assessment of smoked dried catfishes from two indigenous markets in Benue state, Nigeria
Nutritional assessment of processed fish is needed to ensure that such products sold in the local communities are safe for human consumption. Present study aimed at evaluating the nutritional quality of selected catfishes, namely, Clarias gariepinus, Heterobranchus spp and Synodontis spp from Abinsi and Wadata fish markets in Benue State, Nigeria. Samples of smoked catfish each weighing approximately 500 g were sourced from Abinsi and Wadata fish markets, and packaged using foil paper and polythene bags. The smoked fish samples were analysed to determine organoleptic qualities, proximate and mineral composition. The results of the study revealed a significant (p<0.05) variation in proximate and mineral composition of the three smoked catfishes between the two markets. The percentage moisture content for the three species of catfish ranged from 8.19 ± 0.031 to 10.34 ± 0.035%. Synodontis spp. from Abinsi market had the least moisture content (8.19 ± 0.031%) while Heterobranchus spp. from Wadata market had the highest moisture content (10.34 ± 0.035%). Protein content of the three species ranged from 55.80 ± 0.060 to 68.97 ± 0.125%. C. gariepinus from Wadata market had the highest protein content (68.97 ± 0.125%). The lipid content of the fish ranged from 10.37 ± 0.023 to 22.68 ± 0.035. The most abundant mineral was Potassium (K) and was more abundant in C. gariepinus from Wadata market which had the highest K content (410.15 ± 0.895 mg/100 g). Heterobranchus spp. had the highest Calcium (Ca) content (395.48 ± 0.499 mg/100 g), Sodium (Na) (39.84 ± 0.045 mg/100 g) and Zinc (Zn) (0.80 ± 0.015 mg/100 g) while the highest concentration (12.0 ± 0.093 mg/100 g) of Iron (Fe) was recorded in Synodontis spp. The concentrations of Cu, Zn, and Fe in the three species across the markets were well above WHO permissible limits of 20-30 ppm, 30-100 ppm and 50-100 ppm respectively. The smoked catfishes retained good scores for taste, appearance, texture, and odour. However, there was significant (p < 0.05) differences in taste, appearance, texture, and odour for Heterobranchus spp., C. gariepinus and Synodontis spp in Abinsi and Wadata markets. Keywords: Mineral composition, organoleptic qualities, proximate analysis, smoked fish
Geochemical relations among elements in stream sediment samples from Siojan Prospecting Area, Iran using geostatistical methods
Stream sediment samples play an important role in identifying potential areas of metallic and non-metallic mineralization in mineral exploration studies. The relationship of geochemical elements with each other shows how the elements are distributed in the area. Also, by identifying related elements, sampling and targeted chemical analysis can be used in the next stages of exploration. The purpose of this study is to investigate the elements related to the copper element in the Siojan prospecting area, which is located in South-Khorasan province and 30 km northwest of Birjand city of Iran. In Siojan area, 120 stream sediment samples of a 60 square kilometer area were collected to detect geochemical anomalies and were consequently analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for 45 elements. Preliminary geological studies showed that the studied area has copper mineralization potential, and therefore, copper was selected as the target element in this study. Copper trace elements were identified in the area and the results were used to identify copper mineralized anomalies. For the elemental analysis data, methods of Principal Component Analysis (PCA), Factor Analysis (FA), Hierarchical Cluster Analysis (HCA) and K-Means Clustering were performed to identify the relevant elements and relationships among them. Statistical analysis of the concentration of geochemical elements in the region revealed that copper and cobalt elements were identified as two elements of the same family in terms of geochemical genetics. The average value for copper and cobalt elements in the analyzed samples was 27.2 ppm and 15.5 ppm, respectively. Finally, the relationship between copper and cobalt elements was modeled as an equation using the K-Means Clustering algorithm. Keywords: Anomaly separation, Clustering, Copper trace elements, PCA, Factor analysis
Gel properties of agar from two Gracilaria species in Sri Lanka and development of food jellies
Gracilaria species are found to be a rich source of natural hydrocolloid agar-agar but are currently under-exploited in Sri Lanka. The gel characteristics of agar extracted from Gracilaria corticata and Gracilaria edulis from Sri Lankan waters were investigated in this study. The agar yields (%, dry weight basis) obtained from G. corticata and G. edulis by hot-water extraction at 90℃ for 1 h, were 39.91 ± 0.17 and 67.52 ± 1.43, respectively. The gel properties of both agar gels (1.5%, w/v) such as pH, viscosity, gelling and melting temperatures, and syneresis were examined. The viscosity of agar gels (cP) at 80°C was lower than that at 70°C for both species, while G. edulis has shown higher viscosities at both temperatures (1.96 ± 0.06 and 2.76 ± 0.39, respectively). Moreover, the textural analysis revealed that G. corticata has a higher gel hardness (316.7 ± 20.8 g) than G. edulis (113.33 ± 12.58 g). Strawberry-flavored food jellies were developed from agar gels of two Gracilaria species with either artificial (Carmoisine, E122) or natural food color (Annato). Collectively, this study revealed that agar from both red seaweed species has the potential to be developed as plant-based food jellies, and G. edulis can be suggested as the best source to extract agar with higher yield compared to G. corticata. Keywords: Agar, food jellies, Gracilaria spp., red seaweeds, value-addition
Abundance and ecological classification of fish Species: A case study of Owalla Reservoir, Osun State, Nigeria
Globally, we are experiencing higher species extinction rates than ever before which can critically affect food and nutrition security. The ecological classification of fish species was assessed in Owalla reservoir, Okinni, Osun State, Nigeria. Fish landings of fishermen were sampled for 12 months from September 2019 to August 2020). The species were identified and grouped into herbivores, carnivores, and omnivores, and the fish abundance was recorded. The Forage-Carnivore ratio (F/C ratio) was calculated to express the ecological structure of the reservoir. A total of 15 fish species (n=1035 fish) were identified. In the dry and wet seasons, 15 species (692 fish) and 11 species (343 fish) were recorded, respectively, and herbivores were more abundant than carnivores. Chrysichthys nigrodigitatus (25.9%) was the most abundant species and Cichlidae (55.5%) was the most abundant family. The overall F/C ratio during the combined, dry and wet seasons were 1.35, 1.01 and 2.57, respectively. The ecological structure as indicated by the F/C ratio was unbalanced, but in the wet season, it was close to being balanced. We proposed management measures such as fishing across the trophic levels, efficient monitoring and surveillance, regulation of mesh sizes, and registration of fishermen in addition to routine data collection. Keywords: Feeding classification, fish abundance, fish composition, Owalla Reservoir, sustainability.
Classification of the level and the type of hearing loss based on the analysis of audiograms of workers exposed to high level of occupational noise
This paper presents some health effects of workers exposed to high occupational noise for a long period. The main objective of this study was to classify the level and the type of hearing loss of such workers plus to study the effects on their health. Out of a sample of 99 workers exposed to 85 dB(A) or more occupational noise, 73 (74%) workers who were exposed over 40 hours per week for five years or more were selected for this study. Their hearing levels were tested audio-metrically and audiograms of Air Conduction (AC) and Bone Conduction (BC) measurements were taken. Depending on the degree of Hearing Loss (HL) of audiograms, the sample was classified into Normal hearing (0-25 dB(A)) : 10.5%, Mild HL (26-40 dB(A)) : 67.0%, Moderate HL (41-55 dB(A)) : 21.75%, Moderate-to-severe HL (56-70 dB(A)) : 0.75%. None of these fall in to Severe HL or Profound HL categories. Based on the HL and the configuration of audiograms of AC and BC measurements, 89.5% of the sample was classified as Conductive Hearing Loss (CHL 2.25%), Sensorineural Hearing Loss (SNHL 85.75%), and Mixed Hearing Loss (MHL 1.5%). Some SNHL samples were identified as Meniere’s disease 19%, Acoustic Trauma 12%, and Noise-Induced Hearing Loss (NIHL) 6%. NIHL were recorded among highly exposed workers to noise in the frequency range 3000-6000 Hz. Percentage statistics of various levels of hearing levels along–with associated symptoms based on the response to the questionnaire are also presented. Keywords: Noise exposure, Health impacts, Audiometric hearing test, Hearing threshold shift
Characterization and risk evaluation of water samples collected from boreholes situated around a dumpsite in Obalende, Lagos, Nigeria
Dumpsites are used worldwide for waste disposal because they are cost-effective and have the capacity to contain enormous amounts of waste. However, concerns are rife about the impact of dumpsites on the quality of nearby groundwater. The present study assessed the quality of borehole water near a dumpsite in Obalende, Lagos, Nigeria. Heavy metal, physico-chemical, and microbiological tests were performed on the samples of the water using standard techniques, and the results were compared to the WHO permissible limits. The average daily oral ingestion (ADOI), average daily dermal ingestion (ADDI), and hazard quotient (HQ) of the heavy metals were also estimated. The heavy metal analysis revealed non-permissible levels of zinc, iron, lead, and manganese, while nickel, cadmium, and silicon were within the permissible limits. Physico-chemical analysis showed that turbidity, total suspended solids, total dissolved solids, nitrate, and phosphate were within the permissible limits, but not the pH, electrical conductivity, chloride ion, sulphate and dissolved oxygen. The microbiological examination indicated that the water had high levels of bacteria and coliform counts. The HQ of Zn, Fe, and Pb, mainly through dermal exposure was above the recommended limits (>1). Overall, the results suggest that the water may predispose consumers in the area to Zn, Fe, Pb, and Mn toxicities as well as microbial infections. Consequently, consumers are advised to treat the water before consuming it. Keywords: Average daily ingestion, bacteria, dumpsite, Lead, Nitrate
Generalized Stochastic Restricted LARS Algorithm
The Least Absolute Shrinkage and Selection Operator (LASSO) is used to tackle both the multicollinearity issue and the variable selection concurrently in the linear regression model. The Least Angle Regression (LARS) algorithm has been used widely to produce LASSO solutions. However, this algorithm is unreliable when high multicollinearity exists among regressor variables. One solution to improve the estimation of regression parameters when multicollinearity exists is adding preliminary information about the regression coefficient to the model as either exact linear restrictions or stochastic linear restrictions. Based on this solution, this article proposed a generalized version of the stochastic restricted LARS algorithm, which combines LASSO with existing stochastic restricted estimators. Further, we examined the performance of the proposed algorithm by employing a Monte Carlo simulation study and a numerical example. Keywords: LASSO, LARS, Stochastic Linear Restrictions
Analysis of Statistical Downscaling Model (SDSM) projected future rainfall in Northwestern, Western and Southern provinces of Sri Lanka
Even though an extensive amount of climate change studies have been carried out in different parts of the world, Sri Lanka is one of the least focused countries in this regard. Climate projections are important and encouraged to manage the futuristic adverse impacts. Identifying this research gap, future rainfall projections were carried out in three provinces in Sri Lanka, i.e. Northwestern (Puttalam and Kurunegala), Western (Katunayake and Colombo), and Southern province (Galle and Hambantota). The Canadian Earth System Model (CanESM2) under the Representation Concentration Pathways (RCP8.5) was downscaled using the Statistical DownScaling Model (SDSM). Non-parametric tests, including Mann-Kendall (MK) test and the Sen’s Slope estimator, were used to determine the significance of trends and magnitude of the slope of the historical trends (1990-2019) and future projected trends (2020-2100). The trends were analyzed for four major seasons in Sri Lanka, including First Inter-monsoon (FIM), Southwest monsoon (SWM), Second Inter-monsoon (SIM), and the Northeast monsoon (NEM). The standard error and model bias at rainfall stations were 0.014-0.034 mm and 1-1.1 respectively, which are acceptable when compared to previous studies. Several significant rainfall trends were identified, including positive trends in the mid-future (2041-2070), and negative trends in the far-future (2071-2100). In addition, rainfall indices, including Rx5day, R20mm, Consecutive dry days (CDD), and Consecutive wet days (CWD) were tested in future projected and historical rainfalls. The results of the present study will be useful for policymakers for decision-making processes in water resources management and agriculture. Keywords: Non-parametric tests, projected rainfall, rainfall indices, rainfall trends, Statistical Down Scaling Model (SDSM).