Rivers State University of Science and Technology

About: Rivers State University of Science and Technology is a education organization based out in Port Harcourt, Rivers, Nigeria. It is known for research contribution in the topics: Population & Threatened species. The organization has 1826 authors who have published 1833 publications receiving 15183 citations.

Exploratory Study of Crushed Periwinkle Shell as Partial Replacement for Fine Aggregates in Concrete

Abstract: An exploratory study of crushed periwinkle shell (CPWS) as partial replacement for fine aggregate in concrete was carried out. Mechanical and Physical properties of the (CPWS) and fine aggregate (river sand) were determined and compared. Concrete cubes of 1:2:4 and 1:3:6 by weight of cement, were prepared in the laboratory, using the following proportions, 0:100, 30:70, 50:50 and 100:0 CPWS to fine aggregate (river sand). 14, 21 and 28 days compressive strength test were carried out on the concrete cube. The CPWS had an average moisture content of approximately 11.65%, the highest amongst the aggregates. Physical examination of the CPWS particles showed that the grains were angular in shape with rough surface texture. The sieve analysis test revealed that the particle sizes were fine aggregates with about 98.8% passing through the British sieve No. 4 (4.75mm). The CPWS had a bulk density of 1504kg/m3, while that of the river sand was 1636kg/m3. The workability test revealed that the slump values decreased in the concrete mixture as the quantity of CPWS increased. It was also discovered that the compressive strength decreased with increased percentage of replacement of the river sand with CPWS. The control (highest) 28 days compressive strength of the concrete produced with zero percent CPWS and 100% river sand was 24.89N/mm2. 28 days compressive strength of concrete cubes with 50% CPWS and 50% river sand for mix proportion of 1:2:4 was 18.00N/mm2. From the results of this exploratory study, it can be safely concluded that CPWS can be used as a partial replacement of river sand in the production of light weight concrete in areas where the periwinkle shells are in abundance. The purpose of the study is to explore the possibility of turning waste to wealth. A significant factor is that concrete will be produced cheaper in areas with large population of periwinkle shells, while the environment that these periwinkle shells are usually dumped will become better protected.

Food Habits of a Pelomedusid Turtle, Pelomedusa subrufa, in Tropical Africa (Nigeria): The Effects of Sex, Body Size, Season, and Site

Abstract: The food habits of a freshwater pelomedusid turtle (Pelomedusa subrufa) were studied by fecal analysis and stomach flushing in 2 study areas in Nigeria. Males and females were predominantly carnivorous; they fed mainly on fish, tadpoles, and aquatic invertebrates but also on terrestrial vertebrates. Sexes overlapped highly in dietary habits during both wet and dry season. Body size clearly affected diet composition of turtles but did so only during the dry season (with smaller individuals feeding primarily on invertebrates and small vertebrates, and larger individuals on homeotherm vertebrates). There was a strong effect of season on diet composition, and turtles responded to increasing dryness with a shift from a diet based on aquatic organisms during the wet season to a diet based on terrestrial organisms, including small vertebrates, during the dry season.

Long-term, climate-change-related shifts in feeding frequencies of a Mediterranean snake population

Abstract: In a context of climate change, ecological and physiological adaptations of organisms are of central importance for determining the outcome of niche challenges (e.g., with potential competitors) and species persistence. Typically, long-term data on free-ranging populations are needed to investigate such phenomena. Here, long-term data on a free-ranging population of western whip snakes (Hierophis viridiflavus: Colubridae) from central Italy were used in order to test the hypothesis that snake feeding frequencies should increase in relation to climate warming, thus positively affecting individual performance because of longer annual activity period, increased daily activity and larger prey base. Data from 231 ‘female snake-years’ of records (including inter-annual recaptures) were collected were collected between 1990 and 2014. The frequency of fed snakes varied remarkably across the study period with a significant increase over the years. There was a significant positive effect of the mean annual temperature on the percentage of fed animals, whereas there was a non-significant relationship between yearly rainfall and percentage of fed animals. There was a positive relationship between mean annual temperature and yearly diversity-of-prey index. No other climatic variables were significantly correlated with yearly diversity-of-prey index. This study supported the hypothesis that global warming may be favorable for thermophilic species (such as H. viridiflavus), as it enhances their foraging performances and hence their feeding frequencies. The same may not be necessarily true for other species which have colder preferenda (e.g., Zamenis longissimus).