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Embryonic and Larval Development of Reciprocal Crosses between Clarias gariepinus (Burchell, 1822) and Clarias jaensis (Boulenger, 1909) in West Cameroon

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Agricultural Sciences 2024年第8期15卷 848-863页

作者： Justin Ntsoli Félix Meutchieye Algrient Nana towa Donatien Bishakabalya Lwendje Minette Eyango Tabi Tomedi Biotechnology and Bioinformatics Research Unit Department of Animal Science University of Dschang FASA Dschang Cameroon Department of Forestry Faculty of Agronomy and Agricultural Sciences University of Dschang Dschang Cameroon Institute of Fisheries and Aquatic Sciences of the University of Douala Douala Bassa

Establishing intraspecific breeding and hybridization programs and determining genetic variability are two important issues for aquaculture. However, interspecific hybridization to improve growth and feeding efficiency is limited. For this purpose, the embryonic and larval development of reciprocal crosses of Clarias gariepinus (Burchell, 1822) and Clarias jaensis (Boulenger, 1909) were studied under laboratory conditions. The fertilization rate varied from 63.33% to 92%, while the hatching rate ranged from 55.68% to 76% with the highest value in hybrids ♀Cg × ♂Cj. Crosses between ♀Cj × ♂Cj, ♀Cg × ♂Cj and ♀Cj × ♂Cg had embryonic stages similar to those of the pure sib ♀Cg x ♂Cg. All crosses, however, had different timing for the various embryological stages. Hatching occurred at 32 h 15 min and 38 h for ♀Cj × ♂Cj and ♀Cj × ♂Cg, and 23 h and 23 h 30 min, respectively, for ♀Cg × ♂Cg and ♀Cg × ♂Cj. However, both crosses produced viable larvae until the first external feeding. The external morphological features of the larvae were completely formed by the 10th day after hatching. The body forms of the crosses at this time were indistinguishable from the pure sib. This study thus laid the groundwork for further comparative studies on hybrid performance and characterization.

关键词： Embryonic Development Larval Development Interspecific Hybridization Clarias gariepinus Clarias jaensis

Effects of irrigation and weed-control methods on growth of weed and rice

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International Journal of Agricultural and Biological Engineering 2014年第5期7卷 22-33页

作者： Jacob Jeremiah towa Guo Xiangping Key Laboratory of High-Effective Irrigation and Drainage and Agricultural Water and Soil Environment in Southern China Ministry of EducationHohai UniversityNanjing 210098China Irrigation and Technical Services Division Ministry of AgricultureFood Security and CooperativeDar es Salaama9192Tanzania

A field experiment was conducted to study the effects of weeds control methods and an irrigation model on rice growth as well as water consumption and weed quantity in the paddy *** conventional paddy rice production,one of the most important irrigated crops,a significant amount of irrigation water is lost due to percolation and evaporation.A new irrigation model called the Rain-Catching and Controlled Irrigation(RCCI)model has been developed as a viable water-saving technology in the production of paddy *** this study the performance of the RCCI model has been analyzed under mulching,hand weeding and weedy conditions in Jiangsu Province of *** experiment was laid out in Randomized Complete Block Design(RCBD)with three replications and nine *** three replicates consisted of three water management regimes:high dry high flooding(HD-HF),high dry low flooding(HD-LF),and shallow and frequent irrigation(SF)water *** RCCI model was adopted in HD-HF and HD-LF while Flooding Irrigation(CFI)was adopted in SF as a *** nine treatments were equally divided under mulching,hand weeding and weedy *** lowest and maximum irrigation water delivery was 244.86 mm in mulching and 429.22 mm in hand weeding,respectively at *** the lowest and maximum irrigation water delivery was 300.1 mm in the mulching field and 680.72 mm under hand weeding,respectively at *** Nanjing 44 rice variety was *** was observed that weed density and dry weight were significantly influenced by the amount of irrigation water in all the mulching,hand weeding and weedy *** yield and the number of irrigations,the RCCI model produced better results than *** under RCCI was an effective method to control weeds and reduce labor *** addition,mulching decreases the use of herbicides and the risk of *** the other hand,mulching could improve yield and save water.

关键词： irrigation weed control mulching hand weeding RCCI weed population agronomy traits paddy rice

Farming Features of African Bonytongue Fish Heterotis niloticus in Cameroon, Central Africa

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Open Journal of Animal Sciences 2023年第2期13卷 232-248页

作者： Jeanne Wikondi Ema Patrick Jolly Ngono Algrient towa Nana Felix Meutchieye Minette Eyango Tabi Tomedi Department of Genetics and Biostatistics School of Veterinary Medicine and Sciences The University of Ngaoundere Ngaoundere Cameroon Applied Hydrobiology and Ichthyology Research Unit The University of Dschang Dschang Cameroon Department of Animal Science Biotechnology and Bioinformatics Research Unit The University of Dschang Dschang Cameroon Institute of Fisheries and Aquatic Sciences of the University of Douala Douala-Bassa Cameroon

The characterization of African bonytongue Heterotis niloticus fish farming was conducted in the Bi-modal agro-ecological zone of Cameroon from January to May 2021, Thirty-two fish farmers were interviewed and SPSS 6.2 Version was used to analyse the data. The results showed that the majority of fish farmers (81%) are men above 51 years, all of whom are Christians with more than fifty percent of them married. About 43% of them have university level education, and more than 6% of them considered the farming of Heterotis niloticus as their main income-earning activity. The main objective of Heterotis niloticus farming is sales (50%) and the uses (56%) of waged labour. A majority of the farmers produced reared African bonytongue in a polyculture system and 65% of them raised Heterotis niloticus in derivation ponds.

关键词： Aquaculture Characterization African Bonytongue Cameroon Central Africa

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从钨渣中的提取钨,钪,铁和锰

南方冶院科技 1996年第2期 45-46页

作者： towa.,CV 李伟

本工艺适用于从钨渣中提取钨、钪、铁和锰。首先用足量的硫酸在８０℃以上，并在还原剂碳存在下充分溶解钨渣，然后将溶液和残渣分离。溶液中含大部分钪、铁和锰，残渣中含大部分钨。以三浣基伯为萃取剂，芳香酯为溶剂从溶液中萃取钪，... 详细信息

本工艺适用于从钨渣中提取钨、钪、铁和锰。首先用足量的硫酸在８０℃以上，并在还原剂碳存在下充分溶解钨渣，然后将溶液和残渣分离。溶液中含大部分钪、铁和锰，残渣中含大部分钨。以三浣基伯为萃取剂，芳香酯为溶剂从溶液中萃取钪，再用ＨＣｌ将有机萃取剂中的钪反萃下来。或以二尝基磷酸为萃取剂进行萃取，用碳酸铵溶液反萃钪。

关键词：钨钪铁锰提取钨渣

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两相流流过油嘴新相关式

采油工艺情报 1996年第3期 46-49页

作者：王国芬 towa.,Al

本文提出了确定的油井最佳油嘴直径的新经验相关式。它是采用中东１０个油田的３５５４个生产测试数据而得来的，适用于临界流条件。数据统计误差分析表明，此相关优于其它相关式。相关系数为０．９５３４。

关键词：两相流油嘴相关分析临界流动

Leg Atherosclerosis in Japanese COPD Patients: Prevalence of Undiagnosed Peripheral Artery Disease and Association between Leg Atherosclerosis and Clinical Indices

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Open Journal of Respiratory Diseases 2013年第1期3卷 25-30页

作者： Hirofumi Matsuoka Yusuke Matsumoto Kengo Kimura Midori Koyama towa Uzu Yasuko Koma Kensuke Fukumitsu Yoshitaka Kasai Nariyasu Nakashima Daiki Masuya Harukazu Yoshimatsu Yujiro Suzuki Department of Respiratory Medicine Shinko Hospital Kobe Japan

Introduction: Several studies have suggested that decreased FEV1 is associated with cardiovascular risk in COPD patients. Objective: To identify the prevalence of undiagnosed peripheral artery disease (PAD) and the relationship between leg atherosclerosis and clinical indices, which predict COPD mortality in Japanese COPD patients. Methods: We performed a cross-sectional study in 51 COPD patients and 51 age-matched, healthy control smokers. We measured ankle-brachial index (ABI) as a marker of atherosclerosis of the legs, pulmonary function, body mass index, modified Medical Research Council (MMRC) dyspnea scale, and smoking pack-years. We also calculated the ADO index (Age, Dyspnea, and Obstruction), an established predictor of mortality in COPD patients. Co-morbidities including diabetes mellitus, hypertension, and hypercholesterolemia were identified from blood laboratory tests and medical records. Results: Five subjects (9.8%) had an ABI 0.9. ABI was significantly lower in the COPD patients than in the healthy control smokers (p 0.05). The prevalence of PAD was marginally higher in COPD patients than in control smokers (p = 0.09), with the prevalence of ABI 1.0 being significantly higher in COPD patients than in control smokers (p = 0.04). In the COPD patients, ABI showed significant correlations with age (p = 0.006), FEV1 (p = 0.004), smoking pack-years (p = 0.047), MMRC dyspnea scale (p = 0.0005), SaO2 (p = 0.001), andADOindex (p 0.001). Multiple linear regression modeling showed the factors associated independently with ABI were age, FEV1, smoking pack-years, MMRC dyspnea scale, and SaO2. Conclusion: The risk of leg atherosclerosis in Japanese COPD patients is higher than in smokers without COPD. Leg atherosclerosis in COPD patients is associated with clinical indices that predict COPD mortality.

关键词： COPD Peripheral Artery Disease Leg Atherosclerosis Ankle-Brachial Index