The Elusiveness of Light: The Difficulty With Harnessing the Omnipresent Solar Energy in Africa

The world is currently facing an energy crisis. Our dependency on oil and natural gas has led to many global problems, such as OPEC’s oil hikes which have disrupted economies everywhere and caused oil dependent countries to suffer. Our huge consumption of oil has also led to the global warming catastrophe that we currently must combat. The world must find a new energy source soon, or more environmental, political, social, and economic problems will occur. Solar energy’s potential has been recognized for many decades, and its abundant and limitless supply makes it the perfect new form of energy. Solar energy is especially plentiful in Africa where the sun shines all year round. Ironically, this seemingly cure-all solution has not yet been widely exploited in Africa. This situation seems illogical, and this paper strives to investigate the reasons why solar energy has not yet proliferated in Africa. If Africa can adopted solar energy, it will alleviate many economic, social, and political problems for its people and the environment. This paper argues that solar energy proliferation has been challenged by the lack of supply and demand in solar energy caused by extreme poverty and the composition of the African society, hindrances which political instability has only exacerbated. By pointing out the causes of why solar energy usage cannot grow in Africa, the world can change its methods and target the real reasons that are obstructing solar energy expansion. Hopefully shedding light on this riddle will make solar energy become a common source of energy in Africa and the world

Root Cause Analysis Frameworks for Information Systems

Telecommunications systems have evolved to include an ever-growing number of interdependent hardware and software components with complex interactions. This exponential increase in complexity affects the reliability and stability of network systems. This thesis provides two systematic approaches to improve the speed and quality of the Root Cause Analysis task in telecommunications systems. The first approach introduces a new fault analysis framework based on association rule mining and evaluates it for telecommunication systems. The approach describes a strategy using association rules to specifically target faults while improving runtime performance relative to the standard Apache Spark implementation. It also introduces a novel filtering strategy called Cover Set filtering that prunes and merges rule sets to produce high-quality, concise and interpretable results. The proposed framework is evaluated with real-world telecommunication datasets. Compared with other strategies, we demonstrate a better rule diversity in general and a sufficiently compact fault analysis. The second approach tackles Root Cause Analysis from the causal perspective. It is based on Counterfactuals and Nearest Neighbour Matching concepts to identify fault types and highlight the most fault contributing variables. The proposed framework is a proof of concept for finding the root cause of problems based on the causal learning technique. It is demonstrated to be highly compatible with numerical data and highly robust with noisy data. In conclusion, the proposed frameworks improve the quality and performance of fault troubleshooting tasks in telecommunication systems. Last but not least, the proposed frameworks can be adapted to other information systems with minor modifications

Evaluation of short-term toxicity of ammonia and nitrite on the survival of whiteleg shrimp, Litopenaeus vannamei juveniles

The effects of short-term toxicity of total ammonia nitrogen (TAN) and nitrite were estimated in juveniles of Litopenaeus vannamei under laboratory conditions. In the first experiment, L. vannamei juveniles were exposed to different concentrations of ammonia (0, 5, 10, 15, 20, 30, and 40 mg of TAN L-1) or nitrite (0, 5, 10, 20, 30, 40, and 50 mg of NO2--N L-1), using the static renewal method at a salinity of 20 ppt and pH 8.2. The survival rates of juveniles significantly decreased when exposed to increased concentrations of ammonia or nitrite during the 96 h bioassays. The 24, 48, 72, and 96 h LC50 values of TAN in juveniles were 45.5, 30.1, 13.8, and 6.3 mg L-1, respectively, while the LC50 values of NO2--N at 24, 48, 72, and 96 h were 37.6, 16.7, 8.8, and 4.8 mg L-1, respectively. Experiment 2 evaluated the tolerance of L. vannamei juveniles at various salinities (5, 10, 15, and 20 ppt) under a high concentration of ammonia or nitrite (5 mg L-1). Results showed that the survival rates of L. vannamei at 5 ppt and 10 ppt were significantly lower than those at 20 ppt after 72 h and 96 h of exposure

Evaluation of Pseudomonas stutzeri AM1 and Pseudomonas oleovorans ST1.1 isolated from shrimp pond sediments as probiotics for whiteleg shrimp, Litopenaeus vannamei culture

This study aimed to isolate the probiotic potential of nitrifying bacterial strains and to evaluate their effects on water quality and growth performance of the whiteleg shrimp, Litopenaeus vannamei. Based on an initial screening of 100 isolates identified from sediment samples, 12 strains could remove nitrogen compounds and two strains (Pseudomonas stutzeri AM1 and P. oleovorans ST1.1) showed highly efficient nitrogen removal ability. Within 96 h, total ammonia nitrogen (TAN) removal efficiency in the two strains was 28.0-31.6% and 21.5-24.9%, respectively. The water addition of 103 CFUmL-1 of P. stutzeri AM1 (T1) and P. oleovorans ST1.1 (T2) effectively reduced TAN, nitrite, nitrate, and total sulfide and increased the survival rate and biomass of shrimp. However, no significant differences were found between the control (T0) and treatment groups (T1 and T2) in the final weight, weight gain and specific growth rate of shrimp. Overall, P. stutzeri AM1 (T1) and P. oleovorans ST1.1 used as water supplements improved water quality and the survival rate of whiteleg shrimp

IMPLEMENT POLICIES ON TRAINING AND FOSTERING CADRES AND CIVIL SERVANTS OF KHMER IN THE MEKONG DELTA, VIETNAM

Cadres and civil servants who are ethnic Khmer people in the Mekong Delta have an essential position and role in implementing the Party's guidelines and guidelines, policies, and laws of the State to present with the people and directly manage society to achieve order, stability, and development. Cadres and civil servants who are ethnic Khmer people are the bridge between the Party, State, and the people, reflecting the people's legitimate thoughts and aspirations for the Party and State. Based on the method of document research, and secondary data, the paper outlines the characteristics of the Khmer people in the Mekong Delta; viewpoints and lines of the Party, policies, and laws of the State on training and retraining policies for cadres and civil servants who are ethnic Khmer people; On the basis of the actual situation of the policy, the thesis has proposed a number of solutions to improve the effectiveness of the policy on training and fostering cadres and civil servants who are ethnic Khmer people in the Mekong Delta.  Article visualizations

Study of Self-diffusion in GaAs Crystal: Temperature Dependence

The self-diffusion of Ga and As atoms in GaAs crystal with the zince-blende structure (ZnS) is investigated by using the statistical moment method (SMM). The activation energy $(Q)$, diffusion coefficient $(D)$, and pre-exponential factor ($D_0$) are expressed by analytical closed expressions. The present analytical formulas are including the anharmonic effects of the lattice vibrations. The obtained results  are applied to GaAs crystal and the SMM calculations of $Q, D$ and $D_0$  are in agreement with the experimental data

Youths’ word-of-mouth in a developing country: roles of green promotion and green brand loyalty

Purpose – This paper investigates the mediating role of green brand loyalty between green brand image and word-of-mouth (WoM) and the moderating role of green promotion and brand social responsibility among Vietnamese youth. Research methodology – Using an online questionnaire from 1st October 2022 to 31st December 2022, 740 valid responses were collected. Findings – The study reveals that green brand loyalty mediates the relationship between brand trust and WoM. Additionally, green promotion significantly moderates the relationship between brand trust and green brand loyalty. The study concludes that green promotion is vital in influencing consumers’ trust in the brand, subsequently increasing their loyalty. Research limitations – This study has not categorized the groups of environmentally friendly products used by young Vietnamese to see if there is a difference. Practical implications – These results provide significant implications for brand managers to enhance the effectiveness of WoM. Originality/Value – Green promotion is an effective strategy for brands to regain consumers’ loyalty and maintain a close relationship between consumers and green brands. Additionally, green brand loyalty emphasizes the significance of green promotion for developing green companies and can serve as a conduit between customers and brands

Fabrication and evaluation of some electrochemical properties of screen-printed electrodes for use in electrochemical analysis

Three types of conductive inks, including Ceres, Acheson carbon inks, and Ag/AgCl ink, were utilized to fabricate screen-printed electrodes (SPEs) on a 0.4 mm thick polyethylene terephthalate substrate using a screen-printing technique. To enhance the electrical conductivity, the printed electrodes were cured at 80°C for 90 minutes. The basic electrochemical properties of the self-made SPEs using these conductive inks were determined, evaluated, and compared with commercial SPEs from Metrohm. Although the electroactive surface areas of the self-made SPEs were not significantly different from those of the commercial SPEs, the heterogeneous electron transfer rates on the surfaces of self-made SPEs using Ceres and Acheson inks were inferior to those of the commercial SPEs. However, after pre-condition by applying a potential of +1.2 V for 180 s in a 2 M Na2CO3 solution, the electrochemical properties of the self-made SPEs, including the active surface areas and heterogeneous electron transfer rates, were significantly improved and became better than those of the commercial SPEs