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Enhanced adsorptional-photocatalytic degradation of chloramphenicol by reduced graphene oxide-zinc oxide nanocomposite
Improper discharge of waste dry cell batteries and untreated antibiotics laden effluents to the environment pose serious threat to the sustenance of the ecosystem. In this study, synthesis of reduced graphene oxide-ZnO (rGO-ZnO) nanocomposite was achieved via a bioreduction process using waste dry cell battery rod as graphene oxide (GO) precursor. The nanocomposite was applied in the ultraviolet photocatalytic degradation of chloramphenicol (CAP) at 290 nm in the presence of hydrogen peroxide. RGO-ZnO nanocomposite was characterized by SEM, TEM, XRD, BET and FTIR. TEM image of the nanocomposite revealed a polydispersed, quasi-spherical zinc oxide on a coarse reduced graphene oxide surface. XRD patterns showed sharp, prominent crystalline wurtzite hexagonal phases of ZnO and rGO. BET surface area of the nanocomposite was 722 m
2
/g with pore size of 2 nm and pore volume of 0.4 cc/g. % photo-removal efficiency increased with increasing irradiation time but diminished at higher pH, temperature and CAP concentration. Photocatalytic adsorption process fitted more accurately into the Freundlich model (R
2
= 0.99) indicating a multilayer adsorption mechanism. 92.74% reduction in chemical oxygen demand (COD) level of veterinary effluent was obtained after treatment with the nanocomposite thus affirming its effectiveness in real waste water samples.
Journal Article
Anaerobic digestion of gliricidia sepium co-digested with pig manure using automated and portable digester
Promoting biogas as a renewable energy source is strengthened by decentralized anaerobic digestion systems at the community level, providing an innovative approach to managing organic waste and sustaining energy. The anaerobic digestion of pig dung co-digested with
gliricidia sepium
were experimented with over 30 days all using both fabricated and automated digesters. This study used a mixing ratio of the substrate to an inoculum of 1:1 for a hydraulic retention time (HRT) of 30 days in triplicates. The physicochemical and microbial characteristics of the substrates and digestate were analyzed using standard procedures. A statistical analysis was conducted using ANOVA to assess the data. There was a reduction in cellulose concentration by 2% m.m
−1
after the thermo-alkaline pretreatment, which indicates a modification in the structure that aids the breakdown of the biomass during digestion Experimental results show that pig dung co-digested with
gliricidia sepium
produced a gas yield of 0.986772m
3
and 0.50845m
3
from the automated and fabricated digester respectively. When comparing treated and untreated
Gliricidia sepium
, the raw sepium had a higher C/N ratio, ranging from 7 to 8. Iron, zinc, aluminum, copper, Biological oxygen demand, Chemical oxygen demand as well as T.alkalinity, T.nitrogen, T.phosphate, T.carbon, potassium, sulfate, calcium, magnesium, and manganese well as total solids, volatile solids all showed an increase after pre-treatment. This research has shown that significant methane content of gas (58.26%) can be generated from
Gliricidia sepium
co-digested pig manure even at small-household levels.
Journal Article
Underwater Eden : saving the last coral wilderness on earth
\"'It was the first time I'd seen what the ocean may have looked like thousands of years ago.' That's conservation scientist Gregory S. Stone talking about his initial dive among the corals and sea life surrounding the Phoenix Islands in the South Pacific. Worldwide, the oceans are suffering. Corals are dying off at an alarming rate, victims of ocean warming and acidification--and their loss threatens more than 25 percent of all fish species, who depend on the food and shelter found in coral habitats. Yet in the waters off the Phoenix Islands, the corals were healthy, the fish populations pristine and abundant--and Stone and his companion on the dive, coral expert David Obura, determined that they were going to try their best to keep it that way. Underwater Eden tells the story of how they succeeded, against great odds, in making that dream come true, with the establishment in 2008 of the Phoenix Islands Protected Area (PIPA). It's a story of cutting-edge science, fierce commitment, and innovative partnerships rooted in a determination to find common ground among conservationists, business interests, and governments--all backed up by hard-headed economic analysis. Creating the world's largest (and deepest) UNESCO World Heritage Site was by no means easy or straightforward. Underwater Eden takes us from the initial dive, through four major scientific expeditions and planning meetings over the course of a decade, to high-level negotiations with the government of Kiribati--a small island nation dependent on the revenue from the surrounding fisheries. How could the people of Kiribati, and the fishing industry its waters supported, be compensated for the substantial income they would be giving up in favor of posterity? And how could this previously little-known wilderness be transformed into one of the highest-profile international conservation priorities? Step-by-step, conservation and its priorities won over the doubters, and Underwater Eden is the stunningly illustrated record of what was saved. Each chapter reveals--with eye-popping photographs--a different aspect of the science and conservation of the underwater and terrestrial life found in and around the Phoenix Islands' coral reefs. Written by scientists, politicians, and journalists who have been involved in the conservation efforts since the beginning, the chapters brim with excitement, wonder, and confidence--tempered with realism and full of lessons that the success of PIPA offers for other ambitious conservation projects worldwide. Simultaneously a valentine to the diversity, resilience, and importance of the oceans and a riveting account of how conservation really can succeed against the toughest obstacles, Underwater Eden is sure to enchant any ocean lover, whether ecotourist or armchair scuba diver.\"--book jacket.
Book
Mathematical modelling and optimal cost-effective control of COVID-19 transmission dynamics
The novel coronavirus disease (COVID-19) caused by a new strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains the current global health challenge. In this paper, an epidemic model based on system of ordinary differential equations is formulated by taking into account the transmission routes from symptomatic, asymptomatic and hospitalized individuals. The model is fitted to the corresponding cumulative number of hospitalized individuals (active cases) reported by the Nigeria Centre for Disease Control (NCDC), and parameterized using the least squares method. The basic reproduction number which measures the potential spread of COVID-19 in the population is computed using the next generation operator method. Further, Lyapunov function is constructed to investigate the stability of the model around a disease-free equilibrium point. It is shown that the model has a globally asymptotically stable disease-free equilibrium if the basic reproduction number of the novel coronavirus transmission is less than one. Sensitivities of the model to changes in parameters are explored, and safe regions at certain threshold values of the parameters are derived. It is revealed further that the basic reproduction number can be brought to a value less than one in Nigeria, if the current effective transmission rate of the disease can be reduced by 50%. Otherwise, the number of active cases may get up to 2.5% of the total estimated population. In addition, two time-dependent control variables, namely preventive and management measures, are considered to mitigate the damaging effects of the disease using Pontryagin’s maximum principle. The most cost-effective control measure is determined through cost-effectiveness analysis. Numerical simulations of the overall system are implemented in
MatLab
®
for demonstration of the theoretical results.
Journal Article
To catch and reverse a quantum jump mid-flight
In quantum physics, measurements can fundamentally yield discrete and random results. Emblematic of this feature is Bohr’s 1913 proposal of quantum jumps between two discrete energy levels of an atom
1
. Experimentally, quantum jumps were first observed in an atomic ion driven by a weak deterministic force while under strong continuous energy measurement
2
–
4
. The times at which the discontinuous jump transitions occur are reputed to be fundamentally unpredictable. Despite the non-deterministic character of quantum physics, is it possible to know if a quantum jump is about to occur? Here we answer this question affirmatively: we experimentally demonstrate that the jump from the ground state to an excited state of a superconducting artificial three-level atom can be tracked as it follows a predictable ‘flight’, by monitoring the population of an auxiliary energy level coupled to the ground state. The experimental results demonstrate that the evolution of each completed jump is continuous, coherent and deterministic. We exploit these features, using real-time monitoring and feedback, to catch and reverse quantum jumps mid-flight—thus deterministically preventing their completion. Our findings, which agree with theoretical predictions essentially without adjustable parameters, support the modern quantum trajectory theory
5
–
9
and should provide new ground for the exploration of real-time intervention techniques in the control of quantum systems, such as the early detection of error syndromes in quantum error correction.
Experiment overturns Bohr’s view of quantum jumps, demonstrating that they possess a degree of predictability and when completed are continuous, coherent and even deterministic.
Journal Article
PostGIS in action
\"PostGIS in Action, Second Edition teaches you to solve real-world goedata problems. It first gives you a background in vector-, raster-, and topology-based GIS and then quickly moves into analyzing, viewing, and mapping data. You'll learn how to optimize queries for maximum speed, simplify geometrics for greater efficiency, and create custom functions for your own applications. You'll also learn how to apply your existing GIS knowledge to PostGIS and integrate with other GIS tools. What's Inside: An introduction to spatial databases -- geometry, geography, raster, and topology spatial types, functions, and queries -- Applying PostGIS to real-world problems -- Extending PostGIS to web and desktop applications -- Updated for PostGIS 2.x and PostgreSQL 9.x\"--Back cover.
Book
Significance of African Diets in Biotherapeutic Modulation of the Gut Microbiome
Diet plays an essential role in human development and growth, contributing to health and well-being. The socio-economic values, cultural perspectives, and dietary formulation in sub-Saharan Africa can influence gut health and disease prevention. The vast microbial ecosystems in the human gut frequently interrelate to maintain a healthy, well-coordinated cellular and humoral immune signalling to prevent metabolic dysfunction, pathogen dominance, and induction of systemic diseases. The diverse indigenous diets could differentially act as biotherapeutics to modulate microbial abundance and population characteristics. Such modulation could prevent stunted growth, malnutrition, induction of bowel diseases, attenuated immune responses, and mortality, particularly among infants. Understanding the associations between specific indigenous African diets and the predictability of the dynamics of gut bacteria genera promises potential biotherapeutics towards improving the prevention, control, and treatment of microbiome-associated diseases such as cancer, inflammatory bowel disease, obesity, type 2 diabetes, and cardiovascular disease. The dietary influence of many African diets (especially grain-base such as millet, maize, brown rice, sorghum, soya, and tapioca) promotes gut lining integrity, immune tolerance towards the microbiota, and its associated immune and inflammatory responses. A fibre-rich diet is a promising biotherapeutic candidate that could effectively modulate inflammatory mediators’ expression associated with immune cell migration, lymphoid tissue maturation, and signalling pathways. It could also modulate the stimulation of cytokines and chemokines involved in ensuring balance for long-term microbiome programming. The interplay between host and gut microbial digestion is complex; microbes using and competing for dietary and endogenous proteins are often attributable to variances in the comparative abundances of Enterobacteriaceae taxa. Many auto-inducers could initiate the process of quorum sensing and mammalian epinephrine host cell signalling system. It could also downregulate inflammatory signals with microbiota tumour taxa that could trigger colorectal cancer initiation, metabolic type 2 diabetes, and inflammatory bowel diseases. The exploitation of essential biotherapeutic molecules derived from fibre-rich indigenous diet promises food substances for the downregulation of inflammatory signalling that could be harmful to gut microbiota ecological balance and improved immune response modulation.
Journal Article